WO2022153980A1 - Water treatment device and water treatment method - Google Patents

Water treatment device and water treatment method Download PDF

Info

Publication number
WO2022153980A1
WO2022153980A1 PCT/JP2022/000583 JP2022000583W WO2022153980A1 WO 2022153980 A1 WO2022153980 A1 WO 2022153980A1 JP 2022000583 W JP2022000583 W JP 2022000583W WO 2022153980 A1 WO2022153980 A1 WO 2022153980A1
Authority
WO
WIPO (PCT)
Prior art keywords
water
treated
concentrated
coagulation
reverse osmosis
Prior art date
Application number
PCT/JP2022/000583
Other languages
French (fr)
Japanese (ja)
Inventor
祐也 佐藤
猛志 辻
浩司 渕上
亮 功刀
彩 大里
拓也 江川
Original Assignee
Ｊｆｅエンジニアリング株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2021139894A external-priority patent/JP7168739B2/en
Application filed by Ｊｆｅエンジニアリング株式会社 filed Critical Ｊｆｅエンジニアリング株式会社
Publication of WO2022153980A1 publication Critical patent/WO2022153980A1/en

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/04—Feed pretreatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/58—Multistep processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities

Definitions

  • the present invention relates to a water treatment apparatus and a water treatment method.
  • so-called scaling occurs in which salts are precipitated, which causes clogging of the membrane.
  • Scaling is caused by low-solubility salts, and when scaling occurs, it causes a decrease in water permeability of the membrane and an increase in pressure loss on the supply side of raw water, making it difficult to continue the operation of the water treatment apparatus. Salts that cause scaling are components with low solubility.
  • Non-Patent Document 1 the scaling of silica is suppressed by removing calcium to some extent by coagulation precipitation, completely removing calcium by a water softener, and operating in an environment in which the water to be treated is made alkaline by an RO membrane.
  • the method is disclosed.
  • the technique described in Non-Patent Document 1 is used as a water treatment apparatus that suppresses Ca-based scale and silica scale.
  • the present invention has been made in view of the above, and an object of the present invention is a water treatment apparatus capable of improving the water recovery rate while suppressing the generation of scale when extracting water from water to be treated containing impurities. And to provide a water treatment method.
  • the water treatment apparatus is a water treatment apparatus that extracts water from water to be treated containing impurities containing silica, and is the subject. It has at least one of a normal osmotic film and a back permeable film capable of extracting water from a water-containing aqueous solution containing water as a solvent, and having a plurality of agglomerated sedimentation portions for aggregating and removing at least a part of the impurities from the treated water.
  • a first water extraction unit which is a part of the plurality of water extraction units, and a first water extraction unit, which are a part of the plurality of water extraction units, are placed after the first aggregation and sedimentation unit, which is a part of the plurality of coagulation and sedimentation units.
  • the second coagulation sedimentation part which is another part of the plurality of coagulation sedimentation portions, is in the latter stage, and the second water extraction part, which is the other part of the plurality of water extraction parts, is in the rear stage of the second coagulation sedimentation portion.
  • the first coagulation sedimentation section removes a part of the silica from the water to be treated, and then supplies the water to be treated to the first water extraction section.
  • the permeated water is extracted from the water to be treated from which a part of the silica has been removed, the concentrated water is discharged, and the concentrated water is supplied to the second coagulation sedimentation portion.
  • the concentrated water is supplied to the second water extraction unit, and the second water extraction unit has at least one of the normal permeable membrane and the back permeable membrane. Then, the permeated water is extracted from the concentrated water supplied from the second coagulation sedimentation portion, and the highly concentrated water obtained by further concentrating the concentrated water is discharged.
  • the water treatment apparatus is provided with a plurality of filtration units for filtering the water to be treated or the concentrated water, and the first one is provided along the flow direction of the water to be treated.
  • a first filtration section which is a part of the plurality of filtration sections, is provided after the coagulation sedimentation section and before the first water extraction section, and is after the second coagulation sedimentation section and in the second water extraction section.
  • a second filtration unit which is another portion of the plurality of filtration units, is provided in the previous stage.
  • the water treatment apparatus has a pH of 4 or more for the water to be treated supplied to the first filtration unit and the concentrated water supplied to the second filtration unit. It is characterized in that it is configured to be adjustable to 8 or less.
  • the first water extraction unit is composed of a low pressure reverse osmosis unit having a low pressure reverse osmosis membrane
  • the second water extraction unit is a high pressure reverse osmosis unit. It is characterized by comprising a high-pressure reverse osmosis portion having a membrane or a forward osmosis portion having the forward osmosis membrane.
  • the water treatment apparatus is purified water obtained by subjecting the highly concentrated water to at least one of distillation treatment and crystallization treatment in the subsequent stage of the second water extraction unit. It is characterized in that a distillation crystallization unit for discharging water is provided.
  • the impurities contain calcium
  • the first water extraction unit is located after the first coagulation sedimentation unit along the flow direction of the water to be treated.
  • a calcium removing portion capable of removing the calcium is provided at least one of the front stage of the above and the rear stage of the second coagulation sedimentation portion and the front stage of the second water extraction portion.
  • the impurities contain calcium, and calcium is dispersed in the water to be treated in the previous stage of the first water extraction unit along the flow direction of the water to be treated. It is characterized in that it is configured so that an agent can be added.
  • the flocculant that aggregates the silica in the coagulation sedimentation portion is polyaluminum chloride or aluminum chloride
  • the water to be treated is polyaluminum chloride or aluminum chloride. Is added and settled in the coagulation sedimentation portion, and the coagulation sedimentation sludge is contained.
  • the water treatment apparatus is characterized in that, in the above invention, the impurity contains magnesium.
  • the water treatment method is a water treatment method for extracting water from water to be treated containing impurities containing silica, and the silica contained in the impurities with respect to the water to be treated.
  • the permeated water is extracted from the water to be treated by at least one of a normal osmotic film and a back-permeation film, and the water to be treated is treated.
  • the balance of the silica contained in the impurities is aggregated with respect to the concentrated water.
  • the permeated water is extracted from the concentrated water by at least one of a normal osmotic membrane and a back-penetrating membrane, and the concentrated water is further concentrated. It is characterized by including a second water extraction step of discharging concentrated water.
  • the water treatment method according to one aspect of the present invention is characterized in that, in the above invention, the pH of the water to be treated is adjusted to 8 or more and 12 or less in the first coagulation / precipitation step and the second coagulation / precipitation step. And.
  • the water treatment method includes the first filtration step of filtering the water to be treated and the first filtration step after the first coagulation sedimentation step and before the first water extraction step. It is characterized by including a second filtration step of filtering the concentrated water after the second coagulation sedimentation step and before the second water extraction step.
  • the water treatment method adjusts the pH of the water to be treated in the first filtration step to 4 or more and 8 or less, and adjusts the pH of the concentrated water in the second filtration step to 4. It is characterized by adjusting to 8 or less.
  • the first water extraction step includes a low pressure reverse osmosis step of extracting the permeated water by a low pressure reverse osmosis membrane, and the second water extraction step.
  • the second water extraction step is characterized by including a high-pressure reverse osmosis step of extracting the permeated water by a high-pressure reverse osmosis membrane or a normal permeation step of extracting the permeated water by the normal osmosis membrane.
  • At least one of distillation treatment and crystallization treatment is performed on the highly concentrated water to discharge purified water. It is characterized by including a distillation crystallization step.
  • the impurities contain calcium, and after the first coagulation-precipitation step and before the first water extraction step, and in the second coagulation-precipitation step. It is characterized by including a calcium removing step of removing the calcium after and at least one of before and after the second water extraction step.
  • the water treatment method includes a calcium dispersion step in which the impurity contains calcium and a calcium dispersant is added to the water to be treated before the first water extraction step. It is characterized by that.
  • the flocculant that aggregates the silica in the first coagulation-precipitation step and the second coagulation-precipitation step is polyaluminum chloride or aluminum chloride, and the subject. It is characterized by containing a coagulated sedimentation sludge in which polyaluminum chloride or aluminum chloride is added to the treated water and coagulated and precipitated in at least one of the first coagulation sedimentation step and the second coagulation sedimentation step.
  • the water treatment method according to one aspect of the present invention is characterized in that, in the above invention, the impurity contains magnesium.
  • the water treatment apparatus and the water treatment method according to the present invention when water is extracted from the water to be treated containing impurities, it is possible to improve the water recovery rate while suppressing the generation of scale.
  • FIG. 1 is a block diagram schematically showing a water treatment apparatus according to the first embodiment of the present invention.
  • FIG. 2 is a block diagram schematically showing a water treatment apparatus according to a first modification of the first embodiment of the present invention.
  • FIG. 3 is a block diagram schematically showing a water treatment apparatus according to a prior art as a comparative example.
  • FIG. 4 is a block diagram schematically showing a water treatment apparatus according to a second embodiment of the present invention.
  • FIG. 5 is a block diagram schematically showing a water treatment apparatus according to a second modification of the second embodiment of the present invention.
  • FIG. 6 is a block diagram schematically showing a water treatment apparatus according to a third embodiment of the present invention.
  • FIG. 1 is a block diagram schematically showing a water treatment apparatus according to the first embodiment of the present invention.
  • FIG. 2 is a block diagram schematically showing a water treatment apparatus according to a first modification of the first embodiment of the present invention.
  • FIG. 3 is a block diagram schematically
  • FIG. 7 is a block diagram schematically showing a water treatment apparatus according to a third modification of the third embodiment of the present invention.
  • FIG. 8 is a block diagram schematically showing a water treatment apparatus according to a fourth embodiment of the present invention.
  • FIG. 9 is a block diagram schematically showing a water treatment apparatus according to a fourth modification of the fourth embodiment of the present invention.
  • FIG. 10 is a block diagram schematically showing a first configuration example of a coagulation sedimentation portion and a filtration portion according to an embodiment of the present invention.
  • FIG. 11 is a block diagram schematically showing a second configuration example of the coagulation sedimentation portion and the filtration portion according to the embodiment of the present invention.
  • FIG. 12 is a block diagram schematically showing a third configuration example of the coagulation sedimentation portion and the filtration portion according to the embodiment of the present invention.
  • FIG. 13 is a block diagram schematically showing a fourth configuration example of the coagulation sedimentation portion and the filtration portion according to the embodiment of the present invention.
  • FIG. 14 is a block diagram schematically showing an example of a first device of a forward osmosis device according to an embodiment of the present invention.
  • FIG. 15 is a block diagram schematically showing an example of a second device of the forward osmosis device according to the embodiment of the present invention.
  • FIG. 16 is a block diagram schematically showing an example of a third device of the forward osmosis device according to the embodiment of the present invention.
  • FIG. 17 is a block diagram schematically showing an example of a fourth device of the forward osmosis device according to the embodiment of the present invention.
  • the present invention in water treatment for obtaining fresh water by treating an aqueous solution such as blowdown water, seawater, river water, and industrial wastewater as water to be treated, fresh water is suppressed while suppressing scaling caused by calcium salts, silica, and the like.
  • the present invention relates to a technique for improving the recovery rate.
  • Salts that cause scaling are components with low solubility.
  • the causative substances that cause scaling are mainly sparingly soluble salts, such as silica (SiO 2 , silicon dioxide), calcium carbonate (CaCO 3 ), calcium sulfate (CaSO 4 ), and magnesium hydroxide (CaSO 4).
  • Mg (OH) 2 ), barium sulfate (BaSO 4 ), calcium fluoride (CaF 2 ) and the like can be mentioned.
  • Scaling suppression will be described below using CaSO 4 and silica as examples.
  • CaSO 4 is a sparingly soluble salt and does not dissolve in acids or alkalis, so it is difficult to remove it once it is precipitated. Therefore, when CaSO 4 is contained in the water to be treated that is concentrated using a membrane, as a method of preventing CaSO 4 from precipitating, a coagulation sedimentation portion is provided in front of the membrane or a water softener using a cation exchange resin is installed. There are known methods such as removing calcium (Ca) and suppressing the production of CaSO 4 by adding a drug such as a scale dispersant in the pre-stage of the membrane.
  • silica is a general term for substances composed of silicon dioxide or SiO 2 .
  • a pH adjuster such as sodium hydroxide (NaOH)
  • NaOH sodium hydroxide
  • the rate of crystallization decreases.
  • silica it may be possible to suppress the generation of scale consisting of. Further, in order to remove silica, a chemical such as a scale dispersant may be added to the front stage of the membrane as in the case of CaSO 4 .
  • the present inventor further studies, and after removing Ca and silica by further coagulating and precipitating the concentrated water obtained by using a membrane such as an RO membrane, a forward osmosis device or a high pressure is used.
  • a membrane such as an RO membrane, a forward osmosis device or a high pressure is used.
  • the embodiments described below have been devised based on the above-mentioned diligent studies of the present inventor.
  • FIG. 1 is a block diagram schematically showing the water treatment apparatus 1 according to the first embodiment. As shown in FIG.
  • the water treatment apparatus 1 includes a first coagulation sedimentation section 10, a first filtration section 20, a water softener 30, a low pressure reverse osmosis section 40, a second coagulation sedimentation section 50, and a second coagulation sedimentation section.
  • the filtration unit 60, the normal osmosis device 70, and the distillation crystallization unit 80 are provided.
  • the first coagulation-precipitating portion 10 as a part of the plurality of coagulation-precipitating portions is a treatment for coagulating and precipitating the scale component as sludge by adding a coagulant to the water to be treated containing the scale component such as silica and calcium. It is a department.
  • CaCO 3 and silica are removed as scale components.
  • an alkali such as NaOH or calcium hydroxide (Ca (OH) 2 ), sodium carbonate (Na 2 CO 3 ), and polyaluminum chloride (PAC: AlCl 3 ) are added. ..
  • aluminum chloride (AlCl 3 ) may be used instead of polyaluminum chloride.
  • the pH of the reaction vessel (not shown in FIG. 1) that causes coagulation-precipitation is preferably adjusted to 8 or more and 12 or less, for example, 10.5. Further, it is preferable that the concentration of Na 2 CO 3 is equivalent to Ca and the concentration of PAC is twice equivalent to SiO 2 , but it is not always limited.
  • the water to be treated which has been allowed to stand in the first coagulation sedimentation section 10 for, for example, 30 minutes or more, is supplied to the first filtration section 20 after the pH is adjusted to 4 or more and 8 or less, for example, about 6.5.
  • the pH of the water to be treated is adjusted to about 6.5, the aluminum (Al) caused by PAC contained in the water to be treated becomes insoluble.
  • the first filtration unit 20 as a part of the plurality of filtration units is composed of, for example, a sand filter or the like.
  • the first filtration unit 20 may be composed of a membrane filtration device using a predetermined membrane such as a microfiltration membrane (MF membrane) or an ultrafiltration membrane (UF membrane).
  • MF membrane microfiltration membrane
  • UF membrane ultrafiltration membrane
  • the supplied water to be treated containing PAC is allowed to stand for, for example, 30 minutes or more.
  • the unreacted PAC is removed in the first filtration unit 20.
  • the water to be treated from which the PAC has been removed is supplied to the water softener 30. Details of the first coagulation sedimentation section 10 and the filtration section 20 described above will be described later.
  • the water softener 30 as a calcium removing unit is a device that replaces cations such as Ca ions and magnesium (Mg) ions contained in the water to be treated with sodium (Na) ions by a cation exchange resin (cation exchange resin). Is.
  • cation exchange resin cation exchange resin
  • the water softener 30 is provided in front of the low pressure reverse osmosis unit 40, but is not necessarily limited.
  • the water softener 30 is preferably provided between the first coagulation sedimentation portion 10 or the second coagulation sedimentation portion 50 and an apparatus in which scaling is likely to occur. Further, since Mg can be removed by providing the water softener 30, the scale risk of Mg (OH) 2 is efficiently reduced when the low-pressure reverse osmosis portion 40 or the like provided in the subsequent stage is operated under alkaline conditions. can do.
  • an aqueous solution of sodium chloride (NaCl) is used for the regeneration of the water softener 30.
  • NaCl sodium chloride
  • ZLD zero wastewater process
  • the regenerated waste liquid can be treated in the distillation crystallization unit 80.
  • the scale risk of Mg (OH) 2 is high, but since Mg can be removed by the water softener 30, the scale risk in the low pressure reverse osmosis membrane and the high pressure reverse osmosis membrane is reduced. can.
  • a decarbonation tower or a decarbonation film (neither is shown) is installed after the water softener 30. By installing it, it is preferable to suppress the generation of scale consisting of CaCO 3 .
  • the low-pressure reverse osmosis section 40 as a part of the plurality of water extraction sections or the first water extraction section is configured to have a low-pressure reverse osmosis membrane (low-pressure RO membrane).
  • low-pressure RO membrane examples include the product names "ESPA2-LD”, “ESPA2 MAX”, or “ESPA1” (all manufactured by Hydranautics), and the product names "TMG20-400", “TMG20-440C”, or "TLF-400DG” (both manufactured by Toray Industries, Inc.) and the like are used.
  • the low-pressure reverse osmosis unit 40 obtains permeated water having a reduced impurity concentration from the water to be treated by reverse osmosis in which a low pressure of, for example, about 4 MPa is applied, and discharges concentrated water in which impurities are concentrated.
  • the obtained permeated water is recovered as reclaimed water.
  • the discharged concentrated water is supplied to the second coagulation sedimentation section 50.
  • the second coagulation sedimentation section 50 as another part of the plurality of coagulation sedimentation sections is the same as the first coagulation sedimentation section 10 in that the scale component contained in the concentrated water to be treated is coagulated and precipitated as sludge. ..
  • SiO 2 is removed as a scale component. Therefore, unlike the first coagulation sedimentation section 10, PAC is added as a coagulation agent to the concentrated water as the water to be treated of the second coagulation sedimentation section 50.
  • SiO 2 contained in the concentrated water is coagulated and precipitated as sludge and removed.
  • the concentrated water that has been allowed to stand in the second coagulation sedimentation section 50 for, for example, 30 minutes or more is supplied to the second filtration section 60 after the pH is adjusted to 4 or more and 8 or less, for example, about 6.5.
  • the pH of the concentrated water By adjusting the pH of the concentrated water to about 6.5, Al caused by PAC contained in the concentrated water becomes insoluble. It is also possible to adjust the pH of the concentrated water to about 5.
  • the second filtration unit 60 as another unit of the plurality of filtration units is configured in the same manner as the first filtration unit 20.
  • unreacted PAC is removed by allowing the supplied concentrated water to stand for, for example, 30 minutes or more.
  • the concentrated water from which the PAC has been removed is supplied from the second filtration unit 60 to the forward osmosis device 70.
  • the forward osmosis device 70 as the other part or the forward osmosis part of the plurality of water extraction units, for example, a forward osmosis treatment using a temperature-sensitive water absorbing agent is executed to obtain permeated water from the concentrated water, and the concentrated water is produced. It is further concentrated to obtain highly concentrated water (hereinafter referred to as highly concentrated water). In other words, highly concentrated water is concentrated water as opposed to concentrated water. The obtained permeated water is merged with the permeated water discharged from the low-pressure reverse osmosis unit 40 as reclaimed water. On the other hand, the highly concentrated water is supplied to the distillation crystallization unit 80.
  • the material of the forward osmosis (FO: Forward Osmosis) film (not shown in FIG. 1) provided in the forward osmosis apparatus 70 is cellulose acetate
  • cellulose acetate is vulnerable to alkali and can increase the solubility of silica.
  • the forward osmosis device 70 becomes difficult to operate. Therefore, as described above, the water to be treated in the forward osmosis apparatus 70 can be adjusted to neutral by removing silica by the second coagulation sedimentation portion 50 in the previous stage of the forward osmosis apparatus 70, so that the FO film made of cellulose acetate can be adjusted. It is possible to maintain the operation using. Further, in order to suppress the scale of silica, it is desirable to adjust the pH of the outlet on the raw water side of the forward osmosis device 70 to be about 5.5.
  • distillation crystallization unit 80 At least one of distillation treatment and crystallization treatment, that is, conventionally known, is applied to highly concentrated water by supplying predetermined energy, specifically steam (steam) or electric power. Is subjected to purification treatment such as distillation treatment and crystallization treatment, distillation treatment, or crystallization treatment.
  • the purified water purified in the distillation crystallization unit 80 is merged with the permeated water discharged from the low-pressure reverse osmosis unit 40 and recovered as reclaimed water.
  • the salt as a solid component separated from purified water is discarded to the outside. This makes it possible to achieve a zero drainage process (ZLD) that produces as little waste as possible other than solids.
  • ZLD zero drainage process
  • the flow rate of the water to be treated and each component introduced into the water treatment apparatus 1 are as follows. Flow rate: 1000 L / h, TDS (Total Dissolved Solids): 4022 mg / L, Ca: 266 mg / L, SiO 2 : 126 mg / L
  • the pH adjuster added to the water to be treated in the first coagulation sedimentation section 10 is, for example, at least one of NaOH and Ca (OH) 2 , that is, an alkali.
  • the alkali is not limited to these. Thereby, the pH of the water to be treated is adjusted to about 10.5.
  • the flocculants added to the water to be treated in the first coagulation sedimentation section 10 are, for example, Na 2 CO 3 and PAC. It is preferable, but not limited to, that Na 2 CO 3 added here is equivalent to Ca and PAC is added twice equivalent to SiO 2 .
  • the first coagulation-precipitating portion 10 is allowed to stand in this state for about 30 minutes.
  • at least a part of CaCO 3 and silica are aggregated and removed from the water to be treated as scale components.
  • Each component of the water to be treated discharged from the first coagulation sedimentation portion 10 is as follows.
  • TDS 4005 mg / L
  • Ca 50 mg / L
  • the supernatant water obtained by coagulating and precipitating the scale component in the first coagulation sedimentation section 10 is supplied to the first filtration section 20 as water to be treated, and the first filtration step is performed.
  • the pH is adjusted to about 6.5 by adding an acid such as sulfuric acid (H 2 SO 4 ) or HCl.
  • the water to be treated is allowed to stand for 30 minutes or more to remove unreacted PAC.
  • the water to be treated from which the PAC has been removed by the first filtration unit 20 is supplied to the water softener 30 to perform a calcium removal step.
  • Ca is removed from the water to be treated by, for example, a cation exchange resin.
  • the calcium removal step is preferably performed after the first coagulation-precipitation step and the second coagulation-precipitation step described later, and before the step in which scaling of the calcium salt or the like is likely to occur.
  • the water to be treated from which Ca has been removed in the water softener 30 is supplied to the low-pressure reverse osmosis unit 40, and a low-pressure reverse osmosis step as a water extraction step or a first water extraction step is performed.
  • a low-pressure reverse osmosis step as a water extraction step or a first water extraction step is performed.
  • 90% of the reclaimed water is recovered from the water to be treated by an RO membrane on which a predetermined pressure depending on TDS, for example, 4.0 MPa is applied, while 10% concentrated water is produced. It is discharged.
  • the recovery rate of reclaimed water by the low-pressure reverse osmosis section 40 can be improved to 90%.
  • Each component of reclaimed water is as follows. TDS: 40 mg / L, Ca: 0 mg / L, SiO 2 : 1 mg / L That is, in the low-pressure reverse osmosis section 40, TDS is reduced to (40/4030 ⁇ ) 0.01 times and SiO 2 is reduced to (1/10 ⁇ ) 0.1 times.
  • the concentrated water concentrated in the low-pressure reverse osmosis section 40 is supplied to the second coagulation sedimentation section 50 to perform the second coagulation sedimentation step.
  • Ca is removed from the water to be treated by the water softener 30, so that the coagulant added to the concentrated water of the second coagulation sedimentation portion 50 is, for example, PAC that coagulates SiO 2 . be.
  • the PAC added here is preferably added in an amount twice equivalent to SiO 2 .
  • the first coagulation-precipitating portion 10 is allowed to stand in this state for about 30 minutes.
  • at least a part of silica is aggregated and removed from the water to be treated as a scale component.
  • the concentrated water obtained by coagulating and precipitating silica as a scale component in the second coagulation sedimentation section 50 is supplied to the second filtration section 60 to perform the second filtration step.
  • the pH is adjusted to about 5 to 6.5 by adding an acid such as H 2 SO 4 or HCl.
  • the concentrated water is allowed to stand for 30 minutes or more to remove unreacted PAC.
  • Each component of the concentrated water discharged from the second filtration unit 60 is as follows.
  • TDS 40350 mg / L
  • Ca 0 mg / L
  • the concentrated water discharged from the second filtration unit 60 is supplied to the forward osmosis device 70 to perform a forward osmosis treatment step.
  • the forward osmosis device 70 reclaimed water is obtained from the concentrated water, and the highly concentrated water that is further concentrated is discharged.
  • (2/3 ⁇ ) 67% of reclaimed water is recovered from the concentrated water by the FO membrane, while (1/3 ⁇ ) 33% of highly concentrated water is discharged.
  • the water to be treated having a flow rate of 1000 L / h can be discharged as highly concentrated water having a flow rate of 33 L / h.
  • the flow rate of the concentrated water discharged is 250 L / h with respect to the water to be treated having a flow rate of 1000 L / h. That is, according to the water treatment apparatus 1 according to the first embodiment, the water to be treated can be further concentrated and discharged by about 7.6 times as compared with the conventional case, and the recovery rate of the reclaimed water can be significantly improved.
  • distillation crystallization step The highly concentrated water concentrated in the forward osmosis apparatus 70 is supplied to the distillation crystallization unit 80 to perform the distillation crystallization step.
  • the distillation crystallization unit 80 steam or electric power is supplied, and at least one of distillation treatment and crystallization treatment, that is, conventionally known distillation treatment and crystallization treatment, is performed on highly concentrated water at a temperature of, for example, about 120 ° C.
  • Purification treatments such as analysis treatment, distillation treatment, and crystallization treatment are performed.
  • the purification treatment is not limited to the distillation treatment and the crystallization treatment, and various treatments can be adopted as long as it is an evaporation solidification technique.
  • the purified water purified by the distillation crystallization unit 80 is recovered as reclaimed water.
  • the salt as a solid component separated from purified water is discarded to the outside.
  • 4 L / h of solid components are removed from the highly concentrated water having a flow rate of 33 L / h, and purified water having a flow rate of 29 L / h is recovered as reclaimed water.
  • the permeated water obtained from the above low-pressure reverse osmosis unit 40 is supplied with the permeated water obtained from the forward osmosis device 70 and the purified water obtained from the distillation crystallization unit 80 and recovered.
  • Each component of reclaimed water is as follows. TDS: 36 mg / L, Ca: 0 mg / L, SiO 2 : 1 mg / L
  • FIG. 2 is a block diagram schematically showing a water treatment apparatus according to a first modification of the first embodiment.
  • the water treatment device 2 according to the first modification is provided with a high-pressure reverse osmosis unit 90 instead of the forward osmosis device 70 of the water treatment device 1.
  • the high-pressure reverse osmosis section 90 as the other section of the plurality of water extraction sections or the second water extraction section is configured to have a high-pressure reverse osmosis membrane (high-pressure RO membrane).
  • high-pressure RO membrane for example, the product name is "SWC5-LD” or “SWC5 MAX” (both manufactured by Hydranautics), and the product names are "TM820M-440", “TM820R-440", or “TM820V-440". (Both made by Toray Industries, Inc.) are used.
  • the high-pressure reverse osmosis section 90 for example, permeated water having a reduced impurity concentration due to reverse osmosis applied with a high pressure of about 8 MPa is discharged, and highly concentrated water in which the concentrated water is further concentrated is discharged. ..
  • the discharged permeated water is merged with the permeated water discharged from the low-pressure reverse osmosis unit 40 as reclaimed water.
  • the discharged highly concentrated water is supplied to the distillation crystallization unit 80.
  • Other configurations are the same as in the first embodiment.
  • the high-pressure RO membrane when a polyamide-based material is used for the high-pressure RO membrane, it can be operated under alkaline conditions. Therefore, when the removal rate of silica is low in the second coagulation-precipitation section 50, scaling to a high-pressure RO membrane can be suppressed by operating the high-pressure reverse osmosis section 90 under alkaline conditions.
  • the pH similarly to the forward osmosis device 70 described above, the pH can be adjusted to be about 5.5 on the discharge side of the permeated water.
  • the concentrated water discharged from the second filtration section 60 is supplied to the high-pressure reverse osmosis section 90, and a high-pressure reverse osmosis step as a second water extraction step is performed.
  • a high-pressure reverse osmosis step as a second water extraction step is performed.
  • permeated water is obtained from the concentrated water, and more concentrated highly concentrated water is discharged.
  • Each component of highly concentrated water is as follows. TDS: 80700 mg / L, Ca: 0 mg / L, SiO 2 : 20 mg / L
  • highly concentrated water having a flow rate of 50 L / h is discharged from the water to be treated having a flow rate of 1000 L / h.
  • the flow rate of the concentrated water discharged is 250 L / h with respect to the water to be treated having a flow rate of 1000 L / h. That is, according to the water treatment apparatus 2 according to the second embodiment, the water to be treated can be further concentrated and discharged about 5 times as compared with the conventional case, and the recovery rate of the reclaimed water can be significantly improved.
  • distillation crystallization step The highly concentrated water concentrated in the high-pressure reverse osmosis unit 90 is supplied to the distillation crystallization unit 80 to perform the distillation crystallization step.
  • highly concentrated water is purified at a temperature of, for example, about 120 ° C., and the purified purified water is recovered as reclaimed water.
  • the salt as a solid component separated from purified water is discarded to the outside.
  • 4 L / h of solid components are removed from the highly concentrated water having a flow rate of 50 L / h, and purified water having a flow rate of 46 L / h is recovered as reclaimed water.
  • the permeated water obtained from the high-pressure reverse osmosis unit 40 and the purified water obtained from the distillation crystallization unit 80 are supplied to the permeated water obtained from the above low-pressure reverse osmosis unit 40 and recovered.
  • Each component of reclaimed water is as follows. TDS: 36 mg / L, Ca: 0 mg / L, SiO 2 : 1 mg / L
  • FIG. 3 is a block diagram schematically showing a water treatment apparatus according to a prior art as a comparative example described in Non-Patent Document 1.
  • the water treatment apparatus 100 includes a coagulation sedimentation section 110, a filtration section 120, a water softener 130, a low pressure reverse osmosis section 140, and a distillation crystallization section 180.
  • the coagulation sedimentation section 110 is configured to have a conventionally known coagulation sedimentation tank.
  • the filtration unit 120 is composed of a conventionally known sand filtration device.
  • the water softener 130, the low-pressure reverse osmosis unit 140, and the distillation crystallization unit 180 have the same configurations as the water softener 30, the low-pressure reverse osmosis unit 40, and the distillation crystallization unit 80 according to the first embodiment, respectively.
  • the supernatant water obtained by coagulating and precipitating CaCO 3 in the coagulation sedimentation section 110 is supplied to the filtration section 120 as water to be treated, and a filtration step is performed.
  • the water to be treated obtained from the filtration unit 120 is supplied to the water softener 130 to perform the calcium removal step.
  • Ca is removed from the water to be treated.
  • Each component of the water to be treated discharged from the water softener 130 is as follows. TDS: 4134 mg / L, Ca: 0 mg / L, SiO 2 : 126 mg / L
  • the water to be treated from which Ca has been removed in the water softener 130 is supplied to the low-pressure reverse osmosis unit 140 to perform a low-pressure reverse osmosis step.
  • the low-pressure reverse osmosis section 40 75% of the reclaimed water is recovered from the water to be treated by the RO membrane on which a pressure of about 4.0 MPa is applied, while 25% of the concentrated water is discharged.
  • the recovery rate of reclaimed water is at most 75% because the water to be treated supplied to the low-pressure reverse osmosis unit 140 contains silica.
  • Each component of reclaimed water is as follows. TDS: 40 mg / L, Ca: 0 mg / L, SiO 2 : 3 mg / L That is, in the low-pressure reverse osmosis section 140, TDS is reduced to (40/4134 ⁇ ) 0.01 times and SiO 2 is reduced to (3/126 ⁇ ) 0.02 times.
  • Each component of concentrated water is as follows. TDS: 16420 mg / L, Ca: 0 mg / L, SiO 2 : 495 mg / L That is, in the low-pressure reverse osmosis section 140, TDS is concentrated (16420/4134 ⁇ ) 3.9 times and SiO 2 is concentrated (495/126 ⁇ ) 3.9 times in the water to be treated.
  • the low-pressure reverse osmosis unit 140 is operated under alkaline conditions having a pH of about 10 to 10.5 with respect to the water to be treated from which Ca has been removed. Scaling is suppressed (see Non-Patent Document 1, HERO process).
  • the precipitation limit of the silica concentration is at most about 400 mg / L.
  • the concentration ratio by the low-pressure RO membrane is at most about 3 to 4 times.
  • distillation crystallization step The concentrated water obtained by the low-pressure reverse osmosis unit 140 is supplied to the distillation crystallization unit 180 to perform the distillation crystallization step.
  • steam or electric power is supplied to concentrate water at a temperature of about 120 ° C., and at least one of the distillation treatment and the crystallization treatment, that is, the conventionally known distillation treatment and crystallization treatment. , Distillation treatment, or purification treatment such as crystallization treatment.
  • the purified water purified by the distillation crystallization unit 80 is recovered as reclaimed water.
  • the salt as a solid component separated from purified water is discarded to the outside.
  • 4 L / h of solid components are removed from the concentrated water having a flow rate of 250 L / h, and purified water having a flow rate of 246 L / h is recovered as reclaimed water.
  • Each component of reclaimed water is as follows. TDS: 30 mg / L, Ca: 0 mg / L, SiO 2 : 2 mg / L
  • Table 1 shows the ratio of electricity, steam, and cost.
  • Table 2 shows the amount of electric power used and the amount of steam used per unit amount of wastewater in the water treatment devices 100, 1 and 2 adopted in the comparative example, the first embodiment, and the second embodiment.
  • the electric power in the water treatment devices 1 and 2 used in the first example and the second embodiment is 2.3 times and 2.0 times, respectively, as compared with the comparative example. ..
  • the number of the forward osmosis device 70 and the high-pressure reverse osmosis section 90 is increased as compared with the water treatment device 100.
  • the amount of steam used in the water treatment apparatus 100 is 0.23 times and 0, respectively, as compared with the comparative example. It can be seen that it is significantly reduced by 15 times. It is considered that this is because in the water treatment devices 1 and 2, the water to be treated is concentrated in the low pressure reverse osmosis section 40 at a higher concentration than that in the low pressure reverse osmosis section 140 of the water treatment device 100.
  • Distillation treatment and crystallization treatment consume a large amount of steam and electric power, and the cost required for equipment tends to be high. Therefore, it is desirable to reduce the size of the distillation crystallization unit 80. Further, since energy is required to generate steam, the total energy required for the operation of the water treatment devices 1 and 2 is compared with the total energy required for the operation of the water treatment device 100 by significantly reducing the amount of steam used. Can be significantly lowered. As a result, as shown in Table 1, according to the water treatment devices 1 and 2 according to the first embodiment, it is possible to reduce the cost required for equipment and operation by 35 to 40%.
  • Non-Patent Document 1 ZLD is realized by providing a treatment unit for distillation and crystallization in the final stage of the water treatment apparatus, but the required energy is increased. There was a problem. This problem also exists in the wastewater process in which concentrated wastewater other than ZLD is generated, and reduction of the required energy has been required.
  • the water treatment devices 1 and 2 and the water treatment can reduce the energy required while suppressing the generation of scale. A method can be provided.
  • the low-pressure RO film in the low-pressure reverse osmosis section 40 is formed by removing silica in addition to Ca in the first coagulation-precipitation section 10 in the previous stage of the low-pressure reverse osmosis section 40. It is possible to suppress the precipitation of silica generated in the above and suppress the occurrence of scaling. Thereby, the concentration ratio in the low pressure reverse osmosis unit 40 can be improved.
  • a second coagulation sedimentation section 50 is provided between the low pressure reverse osmosis section 40 and the forward osmosis device 70 or the high pressure reverse osmosis section 90, and the concentrated water to be treated is concentrated.
  • a water softener 30 is provided in front of the low-pressure reverse osmosis section 40, and Ca is further removed from the water to be treated in which Ca is partially removed in the first coagulation sedimentation section 10, so that the low-pressure reverse osmosis section 40 The occurrence of scaling due to Ca can be suppressed.
  • the conventional water treatment apparatus 100 for example, it is necessary to perform distillation treatment or crystallization treatment of concentrated water having a flow rate of 250 L / h, whereas water treatment according to the first embodiment and the first modification thereof.
  • water treatment according to the first embodiment and the first modification thereof since highly concentrated water having a flow rate of 33 to 50 L / h may be distilled or crystallized, the total energy can be reduced and the cost can be reduced.
  • Patent Document 3 discloses a technique using an alkali to suppress the scale generated by silica.
  • deterioration of the RO film and the FO film is likely to be promoted, and therefore it is not preferable for the RO film and the FO film to use an alkali in order to suppress the generation of scale.
  • coagulation and precipitation are performed in one step, silica is removed by coagulation and precipitation, and treated water is passed through the RO membrane and then through the FO membrane.
  • silica scale there is a limit to the improvement in enrichment.
  • coagulation and precipitation are performed in two stages, that is, the front stage of the RO membrane and the front stage of the FO membrane, and silica is removed in each of the coagulation precipitations, so that scale is generated in the desalted membrane. Can be significantly suppressed, and high concentration can be achieved.
  • FIG. 4 is a block diagram schematically showing the water treatment apparatus according to the second embodiment.
  • the water treatment device 3 according to the second embodiment is not provided with the water softener 30, and is discharged from the first filtration unit 20.
  • a mechanism (not shown) is provided in which the calcium dispersant is added to the water to be treated.
  • Other configurations are the same as those of the water treatment apparatus 1 according to the first embodiment.
  • a calcium dispersion step of suppressing the production of CaSO 4 is performed by adding a calcium dispersant to the water to be treated from which the PAC has been removed in the first filtration unit 20.
  • the amount of the calcium dispersant added depends on the type of the dispersant, but is preferably 1 mg / L or more and 100 mg / L or less.
  • H 2 SO 4 or HCl that adjusts the pH of the water to be treated from 6.5 to 5.0 is added in the first filtration unit 20. If it is an acidic solution, it is not necessarily limited to these. It is preferable that the calcium dispersion step is performed after the first coagulation-precipitation step and before the step in which scaling of the calcium salt or the like is likely to occur.
  • the water to be treated in which the formation of CaSO 4 is suppressed by the addition of the calcium dispersant, is supplied to the low-pressure reverse osmosis section 40 to perform the low-pressure reverse osmosis step.
  • 90% of reclaimed water is recovered from the water to be treated by a low-pressure RO membrane on which a predetermined pressure depending on TDS, for example, 4.0 MPa is applied, while 10% concentration is performed. Water is drained.
  • Each component of permeated water is as follows. TDS: 40 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L That is, in the low-pressure reverse osmosis section 40, TDS is reduced to (40/4005 ⁇ ) 0.01 times and SiO 2 is reduced to (1/10 ⁇ ) 0.1 times.
  • the concentrated water concentrated in the low-pressure reverse osmosis section 40 is supplied to the second coagulation sedimentation section 50 to perform the second coagulation sedimentation step.
  • the pH adjuster and the flocculant were added to the concentrated water of the second coagulation sedimentation section 50.
  • the pH adjuster added is NaOH or Ca (OH) 2 , similar to the pH adjuster added to the first coagulation sedimentation section 10, but is not necessarily limited.
  • the coagulants added are, for example, Na 2 CO 3 and PAC for aggregating Ca and silica.
  • the concentration of Na 2 CO 3 is equivalent to Ca and the concentration of PAC is twice equivalent to SiO 2 , but it is not always limited.
  • the concentration of Na 2 CO 3 is equivalent to Ca and the concentration of PAC is twice equivalent to SiO 2 , but it is not always limited.
  • the second coagulation sedimentation portion 50 it is allowed to stand in this state for about 30 minutes.
  • CaCO 3 and a part of silica are coagulated and removed from the water to be treated as scale components.
  • the concentrated water obtained by coagulating and precipitating CaCO 3 and silica as scale components in the second coagulation sedimentation section 50 is supplied to the second filtration section 60, and the second filtration step is performed.
  • an acid such as H 2 SO 4 or HCl is added to adjust the pH to about 5 to 6.5.
  • the concentrated water is allowed to stand for 30 minutes or more to remove unreacted PAC.
  • Each component of the concentrated water discharged from the second filtration unit 60 is as follows.
  • TDS 40,000 mg / L
  • Ca 50 mg / L
  • the concentrated water discharged from the second filtration unit 60 is supplied to the forward osmosis device 70 to perform a forward osmosis treatment step, and the reclaimed water is obtained from the concentrated water and the further concentrated highly concentrated water is discharged.
  • the forward osmosis apparatus 70 (2/3 ⁇ ) 67% of reclaimed water is recovered from the concentrated water by the FO membrane, while (1/3 ⁇ ) 33% of highly concentrated water is discharged.
  • Each component of highly concentrated water is as follows.
  • TDS 120,000 mg / L
  • Ca 150 mg / L
  • SiO 2 30 mg / L
  • highly concentrated water having a flow rate of 33 L / h can be discharged from the water to be treated having a flow rate of 1000 L / h. Therefore, according to the water treatment device 3 adopted in the third embodiment.
  • the water to be treated can be further concentrated and discharged about 7.6 times as compared with the conventional technique, and the recovery rate of reclaimed water can be significantly improved.
  • distillation crystallization step The highly concentrated water concentrated in the forward osmosis apparatus 70 is supplied to the distillation crystallization unit 80 in the same manner as in the first embodiment, and the distillation crystallization step is performed.
  • the purified water purified by the distillation crystallization unit 80 is recovered as reclaimed water.
  • the salt as a solid component separated from purified water is discarded to the outside.
  • 4 L / h of solid components are removed from the highly concentrated water having a flow rate of 33 L / h, and purified water having a flow rate of 29 L / h is recovered as reclaimed water.
  • the permeated water obtained from the above low-pressure reverse osmosis unit 40 is supplied with the permeated water obtained from the forward osmosis device 70 and the purified water obtained from the distillation crystallization unit 80 and recovered.
  • Each component of reclaimed water is as follows. TDS: 36 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
  • FIG. 5 is a block diagram schematically showing a water treatment apparatus according to a second modification.
  • the water treatment device 4 according to the second modification is provided with the same high-pressure reverse osmosis unit 90 as the first modification instead of the forward osmosis device 70 of the water treatment device 3.
  • the high-pressure reverse osmosis section 90 for example, permeated water having a reduced impurity concentration due to reverse osmosis applied with a high pressure of about 8 MPa is discharged, and highly concentrated water in which the concentrated water is further concentrated is discharged. ..
  • the discharged permeated water is merged with the permeated water discharged from the low-pressure reverse osmosis unit 40 as reclaimed water.
  • the discharged highly concentrated water is supplied to the distillation crystallization unit 80.
  • Other configurations are the same as in the second embodiment.
  • the water to be treated in the fourth embodiment is the same as the water to be treated in the first to third examples.
  • the first coagulation / precipitation step, the first filtration step, the calcium dispersion step, the low-pressure reverse osmosis step, the second coagulation / precipitation step, and the second filtration step are carried out in the third. Similar to the example.
  • the concentrated water discharged from the second filtration section 60 is supplied to the high-pressure reverse osmosis section 90 to perform the high-pressure reverse osmosis step.
  • the high-pressure reverse osmosis section 90 permeated water is obtained from the concentrated water, and more concentrated highly concentrated water is discharged.
  • Each component of highly concentrated water is as follows. TDS: 80,000 mg / L, Ca: 100 mg / L, SiO 2 : 20 mg / L
  • highly concentrated water having a flow rate of 50 L / h is discharged from the water to be treated having a flow rate of 1000 L / h.
  • the flow rate of the concentrated water discharged is 250 L / h with respect to the water to be treated having a flow rate of 1000 L / h. That is, according to the water treatment apparatus 2 according to the second embodiment, the water to be treated can be further concentrated and discharged about 5 times as compared with the conventional case, and the recovery rate of the reclaimed water can be significantly improved.
  • distillation crystallization step The highly concentrated water concentrated in the high-pressure reverse osmosis unit 90 is supplied to the distillation crystallization unit 80 to perform the distillation crystallization step.
  • highly concentrated water is purified at a temperature of, for example, about 120 ° C., and the purified purified water is recovered as reclaimed water.
  • the salt as a solid component separated from purified water is discarded to the outside.
  • 4 L / h of solid components are removed from the highly concentrated water having a flow rate of 50 L / h, and purified water having a flow rate of 46 L / h is recovered as reclaimed water.
  • the solid component of / h is removed.
  • Each component of the reclaimed water is as follows, as in the second embodiment. TDS: 36 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
  • silica is removed in addition to Ca in the first coagulation sedimentation section 10 in the previous stage of the low pressure reverse osmosis section 40, and the low pressure reverse osmosis section 40, the forward osmosis device 70, and the high pressure reverse osmosis section 40 are removed.
  • FIG. 6 is a block diagram schematically showing the water treatment apparatus according to the third embodiment.
  • the water treatment device 3 according to the third embodiment is not provided with the distillation crystallization unit 80 and is discharged from the forward osmosis device. Highly concentrated water is discarded as concentrated wastewater.
  • Other configurations are the same as those of the water treatment apparatus 3 according to the second embodiment.
  • the water to be treated introduced into the water treatment apparatus 5 in the fifth embodiment is the same as the water to be treated in the first to fourth embodiments. Further, in the water treatment method according to the fifth embodiment, the first coagulation sedimentation step, the first filtration step, the calcium dispersion step, the low pressure back permeation step, the second coagulation sedimentation step, the second filtration step, and the normal permeation treatment step. Is the same as in the third embodiment, but the distillation crystallization step is not performed.
  • the flow rate of the water to be treated discharged from the forward osmosis apparatus 70 in the forward osmosis treatment step is 33 L / h, and each component is as follows.
  • TDS 120,000 mg / L
  • Ca 150 mg / L
  • SiO 2 30 mg / L
  • Each component of highly concentrated water is as follows.
  • TDS 120,000 mg / L
  • Ca 150 mg / L
  • SiO 2 30 mg / L
  • highly concentrated water having a flow rate of 33 L / h can be discharged from the water to be treated having a flow rate of 1000 L / h. Therefore, according to the water treatment device 5 adopted in the fifth embodiment.
  • the water to be treated can be further concentrated and discharged about 7.6 times as compared with the conventional technique, and the recovery rate of reclaimed water can be significantly improved.
  • the highly concentrated water discharged from the forward osmosis device 70 is discarded, and the permeated water obtained from the forward osmosis device 70 is supplied to the permeated water obtained from the low pressure reverse osmosis unit 40 and recovered. Will be done.
  • Highly concentrated water of 33 L / h is discarded.
  • Each component of reclaimed water is as follows. TDS: 37 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
  • FIG. 7 is a block diagram schematically showing a water treatment apparatus according to a third modification.
  • the water treatment device 6 according to the third modification is provided with the same high-pressure reverse osmosis section 90 as the first and second modifications instead of the forward osmosis device 70 of the water treatment device 3.
  • the high-pressure reverse osmosis section 90 permeated water having a reduced impurity concentration was discharged from the concentrated water by reverse osmosis in which a high pressure of, for example, about 8 MPa was applied, and recovered as reclaimed water, and the concentrated water was further concentrated. Highly concentrated water is discarded as concentrated wastewater.
  • Other configurations are the same as in the third embodiment.
  • the water to be treated in the sixth embodiment is the same as the water to be treated in the first to fifth examples.
  • the first coagulation / precipitation step, the first filtration step, the calcium dispersion step, the low-pressure reverse osmosis step, the second coagulation / precipitation step, and the second filtration step are described in the third. It is the same as the embodiment.
  • the high pressure reverse osmosis step is the same as that of the first and second modified examples.
  • highly concentrated water having a flow rate of 50 L / h is discharged from the water to be treated having a flow rate of 1000 L / h.
  • the flow rate of the concentrated water discharged is 250 L / h with respect to the water to be treated having a flow rate of 1000 L / h. That is, according to the water treatment apparatus 6 according to the sixth embodiment, the water to be treated can be concentrated and discharged about 5 times as compared with the conventional case, and the recovery rate of the reclaimed water can be significantly improved.
  • the permeated water obtained from the high-pressure reverse osmosis unit 90 is supplied to the permeated water obtained from the above low-pressure reverse osmosis unit 40 and recovered.
  • the concentrated wastewater of / h is discarded. Since the flow rate of the permeated water recovered from the high-pressure reverse osmosis unit 90 is lower than the flow rate of the permeated water recovered from the forward osmosis device 70, the TDS becomes larger than that of the third embodiment. Therefore, each component of reclaimed water is as follows. TDS: 38 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
  • the first coagulation sedimentation section 10 is provided in front of the low pressure reverse osmosis section 40, and the low pressure reverse osmosis section 40 is located between the forward osmosis device 70 and the high pressure reverse osmosis section 90.
  • FIG. 8 is a block diagram schematically showing the water treatment apparatus according to the fourth embodiment.
  • the water treatment device 3 according to the fourth embodiment does not have the water softener 30 provided in front of the low pressure reverse osmosis unit 40.
  • Is provided in front of the forward osmosis device 70.
  • the water softener 30 is further provided after the second filtration unit 60.
  • Other configurations are the same as those of the water treatment apparatus 1 according to the first embodiment.
  • the water to be treated introduced into the water treatment apparatus 7 in the seventh embodiment is the same as the water to be treated in the first to sixth embodiments. Further, in the water treatment method according to the seventh embodiment, the first coagulation sedimentation step and the first filtration step are the same as those in the first embodiment.
  • Each component of the water to be treated after the first filtration step is as follows as in the first embodiment. TDS: 4005 mg / L, Ca: 50 mg / L, SiO 2 : 10 mg / L
  • the water to be treated from which the PAC has been removed in the first filtration unit 20 is supplied to the low-pressure reverse osmosis unit 40 to perform a low-pressure reverse osmosis step.
  • 90% of reclaimed water is recovered from the water to be treated by a low-pressure RO membrane on which a predetermined pressure depending on TDS, for example, a pressure of 4.0 MPa is applied, while 10% concentrated water is produced. It is discharged.
  • a predetermined pressure depending on TDS for example, a pressure of 4.0 MPa is applied
  • the concentrated water concentrated in the low-pressure reverse osmosis section 40 is supplied to the second coagulation sedimentation section 50 to perform the second coagulation sedimentation step.
  • a pH adjuster and a coagulant are added to the concentrated water of the second coagulation sedimentation section 50.
  • the pH adjuster added is, for example, NaOH or Ca (OH) 2 , like the pH adjuster added to the first coagulation sedimentation section 10, but is not necessarily limited.
  • the coagulants added are, for example, Na 2 CO 3 and PAC for aggregating Ca and silica.
  • the concentration of Na 2 CO 3 is equivalent to Ca and the concentration of PAC is twice equivalent to SiO 2 , but it is not always limited.
  • the second coagulation sedimentation portion 50 it is allowed to stand in this state for about 30 minutes.
  • CaCO 3 and a part of silica are coagulated and removed from the water to be treated as scale components.
  • the concentrated water obtained by coagulating and precipitating CaCO 3 and silica as scale components in the second coagulation sedimentation section 50 is supplied to the second filtration section 60, and the second filtration step is performed.
  • an acid such as H 2 SO 4 or HCl is added to adjust the pH to about 5 to 6.5.
  • the concentrated water is allowed to stand for 30 minutes or more to remove unreacted PAC.
  • Each component of the concentrated water discharged from the second filtration unit 60 is as follows.
  • TDS 40,000 mg / L
  • Ca 50 mg / L
  • the water to be treated from which the PAC has been removed in the second filtration unit 60 is supplied to the water softener 30 to perform a calcium removal step.
  • Ca is removed from the water to be treated by, for example, a cation exchange resin.
  • the concentrated water discharged from the water softener 30 is supplied to the forward osmosis device 70 to perform a forward osmosis treatment step.
  • the forward osmosis treatment step reclaimed water is obtained from the concentrated water, and further concentrated highly concentrated water is discharged.
  • the forward osmosis apparatus 70 (2/3 ⁇ ) 67% of reclaimed water is recovered from the concentrated water by the FO membrane, while (1/3 ⁇ ) 33% of highly concentrated water is discharged.
  • Each component of highly concentrated water is as follows. TDS: 211050 mg / L, Ca: 0 mg / L, SiO 2 : 30 mg / L
  • highly concentrated water having a flow rate of 33 L / h can be discharged from the water to be treated having a flow rate of 1000 L / h.
  • the water to be treated can be further concentrated and discharged by about 7.6 times as compared with the prior art as in the first embodiment, and the reclaimed water can be discharged.
  • the recovery rate can be significantly improved.
  • distillation crystallization step The distillation crystallization step after the forward osmosis treatment step is the same as in the first embodiment. That is, in the seventh embodiment, 4 L / h of solid components are removed from the highly concentrated water having a flow rate of 33 L / h, and purified water having a flow rate of 29 L / h is recovered as reclaimed water.
  • the permeated water obtained from the above low-pressure reverse osmosis unit 40 is supplied with the permeated water obtained from the forward osmosis device 70 and the purified water obtained from the distillation crystallization unit 80 and recovered.
  • Each component of reclaimed water is as follows. TDS: 36 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
  • FIG. 9 is a block diagram schematically showing a water treatment apparatus according to a fourth modification.
  • the water treatment device 8 according to the fourth modification is provided with a high-pressure reverse osmosis unit 90 similar to the first modification instead of the forward osmosis device 70 of the water treatment device 7 according to the fourth embodiment. Be done.
  • the permeated water having a reduced impurity concentration is discharged from the concentrated water, and the highly concentrated water in which the concentrated water is further concentrated is discharged.
  • the discharged permeated water is merged with the permeated water discharged from the low-pressure reverse osmosis unit 40 as reclaimed water.
  • the discharged highly concentrated water is supplied to the distillation crystallization unit 80.
  • the water softener 30 is provided in front of the high-pressure reverse osmosis section 90, so that the scale risk of Mg (OH) 2 is increased when the high-pressure reverse osmosis section 90 is operated under alkaline conditions. Can be reduced.
  • the water to be treated in the 8th example is the same as the water to be treated in the 1st to 7th examples.
  • the first coagulation sedimentation step, the first filtration step, the low pressure reverse osmosis step, the second coagulation sedimentation step, the second filtration step, and the calcium removal step are carried out in the seventh step. Similar to the example.
  • the concentrated water discharged from the water softener 30 is supplied to the high-pressure reverse osmosis unit 90, and the high-pressure reverse osmosis step is performed.
  • the high-pressure reverse osmosis section 90 permeated water is obtained from the concentrated water, and more concentrated highly concentrated water is discharged.
  • Highly concentrated water is discharged at the flow rate of h.
  • Each component of highly concentrated water is as follows. TDS: 80700 mg / L, Ca: 100 mg / L, SiO 2 : 20 mg / L
  • the highly concentrated water having a flow rate of 50 L / h is discharged from the water to be treated having a flow rate of 1000 L / h, and the water treatment apparatus 8 adopted in the eighth embodiment has a flow rate of 50 L / h. According to this, the water to be treated can be further concentrated and discharged about 5 times as compared with the conventional case, and the production efficiency of reclaimed water can be significantly improved.
  • distillation crystallization step The highly concentrated water concentrated in the high-pressure reverse osmosis unit 90 is supplied to the distillation crystallization unit 80 to perform the distillation crystallization step.
  • highly concentrated water is purified at a temperature of, for example, about 120 ° C., and the purified purified water is recovered as reclaimed water.
  • the salt as a solid component separated from purified water is discarded to the outside.
  • 4 L / h of solid components are removed from the highly concentrated water having a flow rate of 50 L / h, and purified water having a flow rate of 46 L / h is recovered as reclaimed water.
  • the solid component of / h is removed.
  • Each component of the reclaimed water is as follows, as in the fourth embodiment. TDS: 36 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
  • silica is removed in addition to Ca in the first coagulation sedimentation section 10 in the previous stage of the low pressure reverse osmosis section 40, and the low pressure reverse osmosis section 40, the forward osmosis device 70, and the high pressure reverse osmosis section 40 are removed.
  • the water softener 30 in front of the forward osmosis device 70 and the high-pressure reverse osmosis unit 90, it is possible to suppress the scaling of Ca that tends to occur in the FO film and the RO film, so that the water treatment devices 7 and 8 are to be treated.
  • the concentration rate of water can be improved as compared with the conventional water treatment apparatus.
  • the coagulation sedimentation section and the filtration section indicate at least one of the first coagulation sedimentation section 10 and the first filtration section 20 and the second coagulation sedimentation section 50 and the second filtration section 60.
  • silicate ion which is a causative substance of silica, takes various forms in water, and is a causative substance of scaling which is extremely difficult to remove from water containing a salt.
  • silicate ions SiO 4 4-
  • two methods have been studied, one is a removal method mainly using a resin or an adsorbent, and the other is a removal method by coprecipitation or coagulation precipitation by administration of a drug.
  • a method for removing silica using a resin or an adsorbent a method for removing silica using an ion exchange resin is known in the pure water production process.
  • the frequency of regeneration of the ion exchange resin increases, so that water treatment is expensive. It is not preferable because it becomes Further, in the vicinity of the exchange capacity of the ion exchange resin, there is a problem that the adsorbed silica is eluted and the silica concentration rapidly increases.
  • the first configuration example, the second configuration example, the third configuration example, and the fourth configuration of the coagulation sedimentation section and the filtration section (hereinafter collectively referred to as the coagulation sedimentation section) described below.
  • An example is a coagulation sedimentation portion that can reduce the amount of coagulant to be added when treating water to be treated.
  • FIG. 10 is a block diagram schematically showing a coagulation sedimentation portion according to the first configuration example.
  • the coagulation sedimentation portions 10A and 50A according to the first configuration example include a receiving tank 11, a reaction tank 12, a pH adjusting tank 13, a pump 14, a dehydrator 15, silica densitometers 16 and 17, and a filtration unit. 20 and 60 are provided.
  • the receiving tank 11 is a tank into which water to be treated, such as wastewater discharged from a cooling tower (not shown), flows into the receiving tank 11.
  • the silica concentration (SiO 2 concentration) in the receiving tank 11 is measured by the silica densitometer 51.
  • the water to be treated containing silica is stored in the receiving tank 11 and then supplied to the reaction tank 12.
  • a flocculant such as PAC that coagulates and precipitates silica and Na 2 CO 3 that coagulates and precipitates Ca is added to the reaction vessel 12.
  • the pH is adjusted to 8 or more and 12 or less, for example, about 10.5, and scale components such as Ca and silica are removed from the water to be treated.
  • the reaction tank 12 can be composed of a plurality of tanks such as two tanks and three tanks capable of inflowing the water to be treated in parallel, and the flow of the treated water can be configured as a plurality of series.
  • the supernatant water obtained in the reaction tank 12 is supplied to the pH adjusting tank 13 and adjusted to a pH of 4 or more and 8 or less, for example, about 6.5. This makes Al in the supernatant water insoluble.
  • the silica concentration in the pH adjusting tank 13 is measured by the silica densitometer 52.
  • the Al-containing water, which is the pH-adjusted water in the pH-adjusting tank 13, is supplied to the filtration units 20 and 60.
  • the filtration units 20 and 60 are configured to have sand filtration or a predetermined film. In the filtration units 20 and 60, a filtration treatment for removing Al from the adjusted water is performed to obtain treated water.
  • the reaction vessel 12 in the coagulation sedimentation portions 10A and 50A scale components including Ca and silica are removed. That is, for example, the water to be treated discharged from the cooling tower or the like is temporarily stored in the receiving tank 11 as the water to be treated containing Ca and silica, and then supplied to the reaction tank 12.
  • the initial state of the reaction vessel 12 is a state in which a part of sludge S as coagulated sludge remains after the coagulation and precipitation treatment has already been performed a plurality of times.
  • the pH of the reaction vessel 12 is adjusted to a pH showing basicity.
  • the reaction vessel 12 stirring is performed by a stirring unit (not shown) while injecting a chemical such as PAC or Na 2 CO 3 in order to remove the scale component, for example.
  • a chemical such as PAC or Na 2 CO 3
  • the agitated sludge S functions as a coagulant and mixes with the silica contained in the water to be treated, and a part of the silica precipitates.
  • the scale component mainly includes silica containing SiO 2 and a compound of Ca such as CaCO 3 , CaSO 4 , and CaF 2 .
  • a part of the sludge S is discharged from the reaction tank 12 in which the sludge has settled by the pump 14 and supplied to the dehydrator 15.
  • the amount of sludge S discharged is preferably the amount of increase in sludge S with respect to the amount of sludge S in the initial state.
  • the discharged sludge S is dehydrated by the dehydrator 15 to become a dehydrated cake, which is discarded or reused for a predetermined purpose.
  • the pH adjuster is added by a drug injection device (not shown) as a pH adjusting means, while stirring is performed by a stirring unit (not shown) as a stirring means.
  • a stirring unit not shown
  • the sludge S is stirred again and becomes a suspension state.
  • the suspended sludge S functions as a coagulant, and a part of silica is adsorbed by the sludge S from the water to be treated and is removed by precipitation.
  • PAC may be further added according to the silica concentration measured in the above-mentioned reaction tank 12.
  • the supernatant water is supplied to the pH adjusting tank 13 in the subsequent stage.
  • water treatment returns to inflow and drug injection.
  • sludge S which is a coagulated sediment sludge that functions as a coagulant.
  • silica contained in the water to be treated such as wastewater from a cooling tower, which flows into the reaction vessel 12, will be described.
  • silica is classified into soluble silica and insoluble colloidal silica in wastewater. According to the experiments of the present invention and the diligent studies accompanying the experiments, it is considered that the aggregated sludge flocs generated by the administration of the aluminum salt have the following effects on the soluble silica and the colloidal silica.
  • soluble silica which mainly contains silicate ions, is negatively charged under basic conditions with a pH of 8 or more and 12 or less.
  • soluble silica under basic conditions has a high reaction rate of polymerizing to insoluble silica.
  • the aggregated sludge floc containing an aluminum salt a positively charged portion derived from an aluminum ion is localized. Therefore, when the present inventor conducted an experiment to reuse the coagulated sediment sludge, the coagulated sludge floc captured more soluble silica than the ionic strength derived from the valence and the number of moles of aluminum ions. It turned out that.
  • the reaction mechanism of soluble silica to aggregated sludge flocs is considered as follows. That is, the negatively charged soluble silica is electrostatically attracted to and adsorbed to a positively charged portion (adsorption active point) such as aluminum ions in the aggregated sludge flocs. Under basic conditions, the rate of polymerization of silicate ions is high, so soluble silica is adsorbed on aggregated sludge flocs by polymerizing with other soluble silicas that are close to the site where silicate ions are adsorbed. To. Therefore, the amount of silica that can be adsorbed is larger than the amount derived from the valence of aluminum.
  • Stirring increases the probability of contact between the soluble silica and the adsorption active points in the aggregated sludge flocs, thus improving the silica removal rate. Further, by increasing the number of times the sludge S is used, that is, the number of cycles, it is possible to reduce the unused adsorption active sites.
  • the colloidal silica is obtained by polymerizing soluble silica with each other to have a size of several tens of nm to several 000 nm. In the case of colloid, the sedimentation property is extremely low because the particle size is small. Further, the colloidal silica under basic conditions is partially dissolved to form a form similar to that of soluble silica, and a reaction similar to the reaction mechanism described above occurs. Even in the undissolved colloidal silica, since the surface is negatively charged, it is electrostatically attracted to the positive charge of aluminum ions, and aggregates and polymerizes to improve the sedimentation property. As a result, silica is removed from the water to be treated.
  • the sludge S obtained by adding a coagulant such as PAC to the water to be treated can be reused a plurality of times, although the silica removal rate is lowered.
  • a coagulant such as PAC
  • the silica removal rate is about 97% to 70% with the number of cycles of sludge S. It turned out to be reduced to.
  • the silica removal rate is improved by about 2 to 2.6 times when the pH is set to 10.5 and the basicity is strengthened as compared with the case where the pH of the water to be treated in the reaction tank 12 is set to 8. did. Therefore, when the silica to be treated is removed from the water to be treated in the reaction vessel 12, the desired silica concentration is set by setting the pH of the water to be treated and the amount of PAC to be added when PAC is added. Will be able to be obtained.
  • sludge S which is coagulation-precipitation sludge generated during the removal of silica
  • sludge S is used again as an adsorption nucleus of silica, that is, as a coagulant.
  • the amount of chemicals such as PAC required for removing silica can be reduced.
  • the sludge S is used as a coagulant, the amount of sludge discharged can be reduced, so that the cost required for the post-treatment of the discharged sludge S can be reduced.
  • sludge S generated at at least one of the first coagulation sedimentation portion 10 and the second coagulation sedimentation portion 50 can be used.
  • FIG. 11 is a block diagram showing a coagulation sedimentation portion according to the second configuration example.
  • the coagulation sedimentation portions 10B and 50B according to the second configuration example include a receiving tank 11, a reaction tank 12, a pH adjusting tank 13, a pump 14, a dehydrator 15, silica densitometers 16 and 17, and a sludge storage tank. 18 and filtration units 20 and 60 are provided.
  • the receiving tank 11, the reaction tank 12, the pH adjusting tank 13, the pump 14, the dehydrator 15, the silica densitometers 16 and 17, and the filtration units 20 and 60 are the same as those in the first configuration example.
  • the sludge storage tank 18 is a tank for temporarily storing the sludge S discharged from the reaction tank 12 and then returning it to the reaction tank 12 by using the pump 14.
  • the scale component containing silica is removed. That is, the water to be treated is temporarily stored in the receiving tank 11 and then supplied to the reaction tank 12.
  • the initial state of the reaction vessel 12 is a state in which a part of sludge S as coagulated sludge remains after the coagulation and precipitation treatment has already been performed a plurality of times.
  • the pH of the reaction vessel 12 is adjusted to a pH showing basicity, for example, 10.5 of 8 or more and 12 or less.
  • stirring is performed by a stirring unit (not shown) while injecting a chemical such as Na 2 CO 3 for removing a compound such as Ca which is a scale component.
  • a stirring unit not shown
  • a chemical such as Na 2 CO 3 for removing a compound such as Ca which is a scale component.
  • a part of the sludge S stored in the sludge storage tank 18 is supplied to the dehydrator 15 for dehydration, while at least a part of the remaining sludge S is supplied to the reaction tank 12. do.
  • the sludge S stirred in the reaction vessel 12 functions as a coagulant and mixes with the silica in the water to be treated, and a part of the silica precipitates.
  • the amount of sludge S supplied to the dehydrator 15 among the sludge S stored in the sludge storage tank 18 is an increase amount increased with respect to the amount of sludge S in the initial state.
  • the sludge S is stirred again and becomes a suspension state.
  • the suspended sludge S functions as a coagulant, and a part of silica is adsorbed by the sludge S from the water to be treated and is removed by precipitation.
  • PAC may be further added according to the silica concentration measured by the above-mentioned silica densitometer. When PAC is added, the addition amount is preferably 1 equivalent or more and 2 equivalents or less of the silica concentration.
  • the supernatant water is supplied to the pH adjusting tank 13 in the subsequent stage.
  • Other configurations are the same as those of the first configuration example.
  • sludge S which is the coagulation sedimentation sludge obtained by the coagulation sedimentation treatment in the reaction tank 12
  • silica flocculant is used as a silica flocculant.
  • the same effect as the configuration example can be obtained.
  • at least a part, preferably all of the sludge S is discharged from the reaction tank 12 and temporarily stored in the sludge storage tank 18, thereby suppressing the reaction between the aluminum flocculant and impurities other than silica. Therefore, the amount of the drug used can be reduced, and the cost of the drug can be reduced.
  • FIG. 12 is a block diagram showing a coagulation sedimentation portion according to the third configuration example.
  • the coagulation and settling portions 10C and 50C according to the third configuration example are the first reaction tank 121, the second reaction tank 122, the settling tank 123, and the pH adjustment provided with the receiving tank 11 and the chemical injection device 19. It includes a tank 13, a pump 14, a dehydrator 15, silica densitometers 16 and 17, and filtration units 20 and 60.
  • the receiving tank 11, the pH adjusting tank 13, the pump 14, the dehydrator 15, the silica densitometers 16 and 17, and the filtration units 20 and 60 are the same as in the first configuration example, respectively.
  • the pH is adjusted by a pH adjustment unit (not shown) so that the water to be treated containing silica is basic, for example, 8 or more and 12 or less. , Preferably adjusted to about 10.5.
  • a flocculant such as Na 2 CO 3 is injected mainly as a scale component other than silica in order to remove a sparingly soluble salt of Ca.
  • stirring is executed by the stirring unit 121a, and the water to be treated is in a suspended state. The water to be treated overflows from the upper part of the first reaction tank 121 and is supplied to the lower part of the second reaction tank 122.
  • sludge S which is the coagulation sediment sludge collected in the sedimentation tank 123 in the subsequent stage
  • a coagulant addition part (not shown) provided in the second reaction tank 122 can be used as a coagulant, for example, PAC.
  • Aluminum salts such as are added.
  • the amount of PAC added to the second reaction vessel 122 is determined based on the measured value of the silica concentration measured by the silica densitometers 16 and 17.
  • the stirring unit 122a In the second reaction tank 122, stirring is executed by the stirring unit 122a, and the water to be treated is in a suspended state.
  • the water to be treated is supplied from the second reaction tank 122 to the settling tank 123. If the silica concentration measured by the silica densitometer 17 in the subsequent stage is equal to or less than the predetermined silica concentration, it is not necessary to add an aluminum salt such as PAC.
  • the agitated sludge S functions as a coagulant and mixes with the silica contained in the water to be treated to precipitate the sludge S containing silica. That is, in the second reaction tank 122, the suspended sludge S functions as a coagulant, and a part of silica is adsorbed on the sludge S from the water to be treated and is removed by precipitating in the settling tank 123.
  • the pH of the water to be treated may be adjusted to 8 or more and 12 or less, preferably about 10.5 by a pH adjusting unit (not shown).
  • At least a part of the sludge S settled in the settling tank 123 is pulled out by the pump 14 as a sludge transport unit.
  • the amount of sludge S extracted by the pump 14 may be substantially the total amount of sludge S in the settling tank 123.
  • the pump 14 supplies a part of the extracted sludge S, for example, 20% of the sedimentation amount of the sludge S, or the amount of sedimentation during the time of the extraction cycle to the dehydrator 15 such as a filter press. Can be done.
  • the pump 14 may pull out only a part of the sludge S in the settling tank 123.
  • the sludge S drawn by the pump 14 can be supplied to the dehydrator 15 with the sludge S having been in contact with the water to be treated a total of a predetermined number of times or more, for example, five times or more.
  • the pump 14 can adjust the withdrawal amount so that a substantially constant amount of sludge S remains in the settling tank 123.
  • the constant amount can be about five times the amount of sludge S that increases in the time for one cycle of pulling out the sludge S. Thereby, the function as a flocculant can be ensured in the sludge S.
  • a part of the sludge S extracted is supplied to the second reaction tank 122 by the pump 14.
  • the balance of the extracted sludge S is supplied to the dehydrator 15 to be dehydrated, and becomes a dehydrated cake for disposal or reuse for a predetermined purpose.
  • a silica densitometer 17 is provided on the outflow side of the water to be treated, which is the subsequent stage of the settling tank 123, and on the inflow side, which is the front stage of the pH adjustment tank 13.
  • the silica concentration meter 17 continuously measures the silica concentration of the supernatant water of the settling tank 123, for example, at intervals of 6 to 10 minutes.
  • the amount of aluminum salt added to the second reaction tank 122 is determined by feedback control based on the silica concentration measured by the silica densitometers 16 and 17.
  • the sludge S is added to the second reaction tank 122, and the suspended sludge S functions as a coagulant to remove silica in the water to be treated.
  • the amount of aluminum salt required for the silica concentration measured by the silica concentration meter 17 to be equal to or less than the desired silica concentration from the silica concentration measured by the silica concentration meter 16 is added to the amount of aluminum salt added.
  • the amount added is preferably 1 equivalent or more and 2 equivalents or less of the measured silica concentration. As a result, the amount of aluminum salt added can be reduced as compared with the conventional case.
  • a plurality of first reaction tanks 121, second reaction tanks 122, and settling tanks 123 are provided, respectively, from the first reaction tank 121, the second reaction tank 122, and the settling tank 123.
  • a plurality of water treatment series may be arranged in parallel to form a plurality of series such as two series or three series capable of treating the water to be treated.
  • At least one other reaction tank may be provided on the upstream side of the first reaction tank 121 along the flow direction of the water to be treated. Further, at least one other reaction tank may be provided between the first reaction tank 121 and the second reaction tank 122 along the flow direction of the water to be treated. In these cases, the second reaction tank 122 may be the most downstream reaction tank along the flow direction of the water to be treated among the plurality of reaction tanks constituting the reaction unit. Further, at least one reaction tank may be further provided on the downstream side of the second reaction tank 122 along the flow direction of the water to be treated.
  • the first reaction tank 121 may be the most upstream reaction tank along the flow direction of the water to be treated in a plurality of reaction tanks constituting the reaction unit. Furthermore, it is possible to combine these configurations. That is, the reaction unit is composed of a plurality of reaction tanks having three or more tanks, and one of these three or more reaction tanks is designated as the first reaction tank 121, and at least on the downstream side of the first reaction tank 121. One of the reaction tanks in one tank may be used as the second reaction tank 122.
  • first reaction tank 121 may be composed of a plurality of reaction tanks
  • second reaction tank 122 may be composed of a plurality of reaction tanks
  • the settling tank 123 constituting the settling portion may be composed of a plurality of settling tanks in which the water to be treated is transported in series.
  • the supernatant water obtained in the settling tank 123 is supplied to the pH adjusting tank 13 and adjusted to a pH of 4 or more and 8 or less, for example, about 6.5. As a result, Al in the supernatant water becomes insoluble and is removed.
  • the Al-containing water which is the pH-adjusted water in the pH-adjusting tank 13, is supplied to the filtration units 20 and 60. A part of the Al-containing water whose pH has been adjusted in the pH adjusting tank 13 may be returned to the second reaction tank 122.
  • a filtration process is performed to remove Al from the adjustment water supplied from the pH adjustment tank 13. As a result, treated water is obtained.
  • the aluminum salt is generated in the second reaction tank 122. It is possible to suppress consumption by substances other than silica.
  • the sludge S which is the coagulation sediment sludge settled in the sedimentation tank 123, is transferred to the reaction tank in the previous stage of the sedimentation tank 123, specifically, the second reaction tank 122.
  • the silica is removed from the water to be treated. That is, in the third configuration example, the sludge S coagulated and precipitated in the settling tank 123 is put into the second reaction tank 122 and used again as an adsorption nucleus of silica, that is, as a coagulant, so that the silica can be removed.
  • the amount of chemicals such as PAC required can be reduced.
  • the sludge S is used as a flocculant, the amount of the sludge S to be discharged can be reduced, so that the cost required for the post-treatment of the discharged sludge S can be reduced.
  • FIG. 13 is a block diagram showing a coagulation sedimentation portion according to the fourth configuration example.
  • the coagulation and settling portions 10D and 50D according to the fourth configuration example have the receiving tank 11, the first reaction tank 121, the second reaction tank 122, the settling tank 123, and the pH adjustment, similarly to the third configuration example. It includes a tank 13, a pump 14, a dehydrator 15, silica densitometers 16 and 17, a chemical injection device 19, and filtration units 20 and 60.
  • the agitated sludge S functions as a coagulant and is mixed with the silica contained in the water to be treated to contain silica.
  • Sludge S precipitates. At least a part of the settled sludge S is pulled out by the pump 14.
  • the amount of sludge S to be extracted is preferably, but is not limited to, the amount of increase in sludge S in the settling tank 123. In other words, in the settling tank 123, it is preferable to adjust the withdrawal amount so that a substantially constant amount of sludge S remains.
  • a part of the extracted sludge S is supplied to the first reaction tank 121 by the pump 14.
  • sludge S is transported and added to the first reaction tank 121 from the settling tank 123 in the subsequent stage.
  • a part of silica in the first reaction tank 121 is removed by the added sludge S.
  • the pH is adjusted so that the water to be treated is basic, for example, 8 or more and 12 or less, preferably about 10.5.
  • a Ca flocculant such as Na 2 CO 3 is injected mainly as a scale component other than silica in order to remove, for example, a sparingly soluble salt of Ca.
  • stirring is executed by the stirring unit 121a, and the water to be treated is in a suspended state.
  • the sparingly soluble salt of Ca is removed by the flocculant of Ca, and a part of silica is removed by the sludge S.
  • the suspended water to be treated overflows from the upper part of the first reaction tank 121 and is supplied to the lower part of the second reaction tank 122.
  • the silica concentration of the water to be treated is measured by a silica densitometer 16 provided in the subsequent stage of the first reaction tank 121 and in front of the second reaction tank 122.
  • the silica concentration of the water to be treated may be measured in the first reaction tank 121.
  • the subject in the second reaction tank 122 is based on the silica concentration of the water to be treated flowing out from the first reaction tank 121 and the silica concentration of the water to be treated flowing out from the settling tank 123.
  • the amount of aluminum salt added to the treated water is determined. That is, the silica concentration of the supernatant water of the settling tank 123 is continuously measured by the silica densitometer 17 at intervals of, for example, 6 to 10 minutes.
  • the silica concentration meter 16 measures the silica concentration of the water to be treated flowing out of the first reaction tank 121 at intervals of, for example, 6 to 10 minutes.
  • the amount of aluminum salt added to the second reaction vessel 122 is determined by feedback control based on the silica concentration measured by the silica densitometers 16 and 17.
  • Other configurations are the same as those of the third configuration example.
  • sludge S which is the coagulation sedimentation sludge obtained by the coagulation sedimentation treatment in the first reaction tank 121, the second reaction tank 122, and the sedimentation tank 123, is subjected to.
  • the sludge S functioning as a coagulant is charged into the first reaction tank 121, and the silica concentration is measured on the downstream side of the first reaction tank 121, whereby the sludge S is charged.
  • the amount of aluminum salt added in the second reaction vessel 122 can be optimized. Further, the water to be treated is injected from the receiving tank 11 to the lower part of the first reaction tank 121, and the water to be treated is overflowed from the upper part of the first reaction tank 121 and injected into the lower part of the second reaction tank 122. As a result, the amount of sludge S invading can be suppressed, so that the reaction between the newly injected aluminum salt such as PAC and sludge S can be suppressed, and the silica removal rate can be further improved as compared with the third configuration example.
  • the first coagulation sedimentation portion 10 and the second coagulation sedimentation portion 50 may have the same configuration or different configurations.
  • the chemicals used as the coagulant in the first to fourth constituent examples described above include a coagulant that causes coagulation and precipitation by adding to the water to be treated, and silica that coagulates and precipitates by the coagulant, and is to be treated. It is a chemical consisting of coagulated sediment sludge that is coagulated and precipitated by adding a coagulant to water.
  • the flocculant that causes coagulation / precipitation by adding to the water to be treated is composed of at least one compound selected from an aluminum salt, a magnesium salt, an iron salt, and a polymer-based flocculant.
  • the chemicals used as the coagulant in the above-mentioned first to fourth constitutional examples include a step of adding the coagulant to the water to be treated and a step of coagulating and precipitating silica contained in the water to be treated to generate coagulated sediment sludge. It can be manufactured by a manufacturing method including. At this time, it is preferable to adjust the pH of the water to be treated to 8 or more and 12 or less.
  • the energy consumption required for cooling and heating is suppressed while simplifying the piping structure, and the energy is reduced. It is a forward osmosis device that can stabilize the balance of energy.
  • FIG. 14 is a block diagram schematically showing a forward osmosis device according to the first device example.
  • the forward osmosis device 71 according to the first device example includes a membrane module 711, a heat exchanger 712, 713, a heater 714, a separation tank 715, and a final processing unit 716.
  • the membrane module 711 is, for example, a cylindrical or box-shaped container, and the inside is divided into two chambers by the semipermeable membrane 711a by installing the semipermeable membrane 711a as a forward osmosis membrane inside.
  • Examples of the form of the membrane module 711 include various forms such as a spiral module type, a laminated module type, and a hollow fiber module type.
  • As the membrane module 711 a known semipermeable membrane device can be used, and a commercially available product can also be used.
  • the semipermeable membrane 711a provided in the membrane module 711 is preferably one that can selectively permeate water, and an FO membrane is used, but an RO membrane may also be used.
  • the material of the separation layer of the semipermeable membrane 711a is not particularly limited, and examples thereof include materials such as cellulose acetate-based, polyamide-based, polyethyleneimine-based, polysulfone-based, and polybenzimidazole-based.
  • the semipermeable membrane 711a may be composed of only one type (one layer) of the material used for the separation layer, and has a support layer that physically supports the separation layer and does not substantially contribute to separation2. It may be composed of layers or more.
  • the support layer examples include materials such as polysulfone-based, polyketone-based, polyethylene-based, polyethylene terephthalate-based, and general non-woven fabric.
  • the form of the semipermeable membrane 711a is also not limited, and various forms of membranes such as flat membranes, tubular membranes, and hollow fibers can be used.
  • An aqueous solution containing an aqueous solution can be flowed into one chamber partitioned by the semipermeable membrane 711a inside the membrane module 711, and a draw solution which is an absorbing aqueous solution can be flowed into the other chamber.
  • the pressure for introducing the draw solution into the membrane module 711 is 0.1 MPa or more and 0.5 MPa or less, and in the first apparatus example, for example, 0.2 MPa.
  • the aqueous solution contains, for example, concentrated water, seawater, brackish water, brackish water, industrial wastewater, accompanying water, or sewage, or, if necessary, filtered treatment of these waters and contains water as a solvent.
  • a solution mainly composed of a temperature-sensitive water absorbing agent (polymer) having at least one cloud point is used.
  • a temperature-sensitive water absorbent is hydrophilic at low temperatures and dissolves well in water to increase the amount of water absorption.
  • the amount of water absorption decreases as the temperature rises, and when the temperature rises above a predetermined temperature, it becomes hydrophobic and the solubility decreases. It is a substance.
  • the polymer is preferably a block or random copolymer containing at least a hydrophobic part and a hydrophilic part
  • the basic skeleton contains at least one group consisting of ethylene oxide group and propylene oxide and butylene oxide.
  • the basic skeleton include a glycerin skeleton and a hydrocarbon skeleton.
  • an agent having a polymer of ethylene oxide and propylene oxide GE1000-BBPP (A3) or the like
  • the temperature at which water solubility and water insolubility change is called the cloud point.
  • the hydrophobic temperature-sensitive water absorbent aggregates and becomes cloudy.
  • the temperature-sensitive water absorbent is used as various surfactants, dispersants, emulsifiers and the like.
  • the draw solution is used as an attractant to attract water from the aqueous solution.
  • the membrane module 711 water is attracted from the aqueous solution to the draw solution, and the diluted draw solution (diluted draw solution) flows out.
  • the heat exchanger 712 is provided on the upstream side of the membrane module 711 along the flow direction of the aqueous solution.
  • the heat exchanger 712 is provided on the downstream side along the flow direction of the recycled draw solution (hereinafter referred to as the regenerated draw solution) flowing out from the separation tank 715, which will be described later, and the regenerated draw solution flowing out from the separation tank 715.
  • Heat exchange is performed between the surface and the aqueous solution supplied from the outside.
  • the flow rate of the aqueous solution flowing into the heat exchanger 712 is temperature-controlled so that the temperature of the regenerated draw solution supplied to the membrane module 711 becomes a predetermined temperature.
  • the temperature of the regenerated draw solution supplied to the membrane module 711 is controlled to a predetermined temperature of 25 ° C. or higher and 50 ° C. or lower, for example, about 40 ° C. If it is necessary to keep the temperature of the regenerated draw solution at a desired temperature and keep the flow rate of the aqueous solution supplied to the membrane module 711 constant, adjust the temperature between the membrane module 711 and the heat exchanger 712. It is desirable to provide a blow valve (not shown) as a valve.
  • the heat exchanger 713 is provided on the downstream side of the membrane module 711 along the flow direction of the diluted draw solution. Further, the heat exchanger 713 is provided on the downstream side along the flow direction of the water-rich solution flowing out from the separation tank 715, which will be described later, and is obtained by the diluted draw solution flowing out from the membrane module 711 and the separation tank 715. Heat exchange with the water-rich solution.
  • the heater 714 as a means for heating the draw solution is provided on the upstream side of the separation tank 715 along the flow direction of the draw solution.
  • the heater 714 heats the diluted draw solution that flows out of the membrane module 711 and is heat exchanged by the heat exchanger 713 above the cloud point temperature.
  • the diluted draw solution heated above the cloud point temperature by the heater 714 is phase-separated into polymer and water.
  • the diluted draw solution phase-separated by the heater 714 is separated into a water-rich solution mainly composed of water and a draw solution mainly composed of a polymer having a lower water content than the water-rich solution. Will be done.
  • the draw solution having a lower water content than the water-rich solution is supplied to the membrane module 711 as a regenerated draw solution via the heat exchanger 712.
  • the final treatment unit 716 as the separation treatment means is composed of, for example, a corelesser, an activated carbon adsorption unit, a UF membrane unit, a nanofiltration membrane (NF membrane) unit, or an RO membrane unit.
  • the final treatment unit 716 separates the remaining polymer from the water-rich solution in the water-rich solution flowing out of the separation tank 715 to produce fresh water as permeated water.
  • the polymer solution containing the polymer separated by the final treatment unit 716 may be discarded or introduced into the diluted draw solution at least upstream of the heater 714.
  • a part of the separated polymer solution and introduce the remaining polymer solution as a draw solution into a diluted draw solution at least on the upstream side of the heater 714 or the upstream side of the heat exchanger 713. ..
  • a method of introducing the polymer solution into the diluted draw solution not only a method of introducing the diluted draw solution into the pipe through which the diluted draw solution flows, but also a method of introducing the diluted draw solution into a tank (not shown) for temporarily storing the diluted draw solution, etc. , Various methods can be adopted.
  • the inflow side heat exchange step is performed. That is, the aqueous solution contained in the water treatment device 1 supplied from the outside is first supplied to the heat exchanger 712. On the other hand, the regenerated draw solution flowing out of the separation tank 715 is supplied to the heat exchanger 712. In the first device example, the regenerated draw solution is adjusted to a predetermined temperature, specifically, for example, about 40 ° C. by the heat exchanger 712. As will be described later, since the heated diluted draw solution flows into the separation tank 715, the temperature of the regenerated draw solution flowing out of the separation tank 715 is higher than that of the aqueous solution-containing solution.
  • the heat exchanger 712 lowers the temperature of the regenerated draw solution.
  • the flow rate of the aqueous solution containing water flowing into the heat exchanger 712 is adjusted in order to lower the temperature of the regenerated draw solution to a predetermined temperature. That is, in the heat exchanger 712, the regenerated draw solution is cooled by the regenerated aqueous solution, while the regenerated aqueous solution is heated by the regenerated draw solution.
  • a blow valve (not shown) as a regulating valve is provided between the membrane module 711 and the heat exchanger 712 to maintain the temperature of the regenerated draw solution at a desired temperature while supplying an aqueous solution to the membrane module 711. It is also possible to adjust the flow rate of.
  • the regenerated draw solution heated by heat exchange is supplied to the other chamber of the membrane module 711, and the aqueous solution containing heat exchanged and heated is supplied to one chamber of the membrane module 711. Ru.
  • the forward osmosis step as the second water extraction step is performed. That is, in the membrane module 711, when the aqueous solution and the regenerated draw solution are brought into contact with each other via the semipermeable membrane 711a, the water in the aqueous solution passes through the semipermeable membrane 711a and moves to the regenerated draw solution due to the osmotic pressure difference. .. Water moves from one of the chambers to which the aqueous solution is supplied, and the concentrated aqueous solution flows out. Water moves from the other chamber to which the regenerated draw solution is supplied and the diluted diluted draw solution flows out.
  • the heat exchanger 712 heat is exchanged between the aqueous solution and the regenerated draw solution, so that the aqueous solution containing substantially the same temperature and the regenerated draw solution are inside the membrane module 711. , Water is moved. Therefore, the temperature of the diluted draw solution flowing out from the membrane module 711 is substantially the same as the temperature of the regenerated draw solution.
  • Heating process In the heater 714 as a heating means, a heating step is performed. That is, the diluted draw solution diluted by moving water from the aqueous solution in the forward osmosis step is heated in the outflow side heat exchange step described later, and then heated to a temperature higher than the cloud point by the heater 714. , At least a portion of the polymer is agglomerated and phase separated.
  • the heating temperature in the heating step can be adjusted by controlling the heater 714.
  • the heating temperature is preferably 100 ° C. or lower, and in the first apparatus example, the heating temperature is, for example, 88 ° C., which is equal to or higher than the cloud point and 100 ° C. or lower.
  • a water separation step is performed. That is, in the separation tank 715, the diluted draw solution is separated into a water-rich solution containing a large amount of water and a concentrated regenerated draw solution containing a high concentration of polymer.
  • the pressure in the separation tank 715 is atmospheric pressure.
  • the phase separation between the water-rich solution and the regenerated draw solution can be performed by allowing the solution to stand at a liquid temperature equal to or higher than the cloud point. In the first apparatus example, the liquid temperature is, for example, 88 ° C., which is equal to or higher than the cloud point and 100 ° C. or lower.
  • the draw solution separated from the diluted draw solution and concentrated is supplied to the membrane module 711 as a regenerated draw solution.
  • the draw concentration of the regenerated draw solution is, for example, 60 to 95%.
  • the water-rich solution separated from the diluted draw solution is supplied to the final processing unit 716 via the heat exchanger 713.
  • the water-rich solution is, for example, 99% water and 1% draw concentration.
  • the outflow side heat exchange step is performed. That is, the diluted draw solution flowing out of the membrane module 711 is first supplied to the heat exchanger 713.
  • the water-rich solution obtained in the separation tank 715 is supplied to the heat exchanger 713.
  • the water-rich solution is adjusted to a predetermined temperature, specifically, for example, about 45 ° C. by the heat exchanger 713.
  • the water separation step is performed when the liquid temperature is above the cloud point and below 100 ° C.
  • the processing temperature in the final processing unit 716 in the subsequent stage is, for example, 20 ° C. or higher and 50 ° C. or lower, preferably 35 ° C. or higher and 45 ° C. or lower, and in the first apparatus example, for example, 45 ° C. Therefore, in the heat exchanger 713, the temperature is adjusted to lower the temperature of the water-rich solution to a predetermined temperature. That is, in the heat exchanger 713, the water-rich solution is cooled by the diluted draw solution, while the diluted draw solution is heated by the water-rich solution.
  • a final processing step as a separation processing step is performed. That is, the polymer may remain in the water-rich solution separated in the separation tank 715. Therefore, in the final treatment unit 716, permeated water such as fresh water can be obtained by separating the polymer solution to be the separation treatment draw solution from the water-rich solution.
  • the permeated water separated from the water-rich solution is supplied to the required external applications as the final product obtained from the aqueous solution.
  • the draw solution separated from the permeated water is a polymer solution having a draw concentration of about 0.5 to 25%, and is discarded to the outside, or at least the heater 714 or the heat exchanger 713. It is introduced into the diluted draw solution on the upstream side of. It is also possible to discard part of the polymer solution separated from the permeated water and introduce the remaining polymer solution into a diluted draw solution at least upstream of the heater 714 or upstream of the heat exchanger 713.
  • the forward osmosis device 71 configured as described above will be described.
  • a case where the forward osmosis device 71 is used to generate fresh water (permeated water) having a flow rate of 67 L / h from an aqueous solution (concentrated water) having a flow rate of 100 L / h will be described as an example. do.
  • heat exchange is performed with the concentrated water introduced from the outside into the forward osmosis apparatus 71 by the heat exchanger 712, and the concentrated water having a temperature of 40 ° C. is supplied to the membrane module 711.
  • the concentrated water concentrated by the membrane module 711 is discharged from the membrane module 711 at a flow rate of 33 L / h. That is, in the membrane module 711, water is moved at a flow rate of 67 L / h.
  • the regenerated draw solution having a temperature of 40 ° C. which has been heat-exchanged with concentrated water in the heat exchanger 712, is supplied to the membrane module 711, diluted, and flows out as a diluted draw solution.
  • the flow rate of the regenerated draw solution is 100 L / h.
  • the temperature of the diluted draw solution flowing out of the membrane module 711 is 40 ° C., and the flow rate is 167 L / h.
  • the diluted draw solution is heated by heat exchange with a water-rich solution at 88 ° C. in the heat exchanger 713, heated to a temperature of 40 ° C. to 52 ° C., and then supplied to the heater 714 to be further heated.
  • the temperature is raised from 52 ° C. to 88 ° C.
  • the diluted draw solution is supplied to the separation tank 715 and phase-separated into the regenerated draw solution and the water-rich solution.
  • the regenerated draw solution has a temperature of 88 ° C. and a flow rate of 100 L / h.
  • the water-rich solution has a temperature of 88 ° C. and a flow rate of 67 L / h.
  • the regenerated draw solution is supplied to the heat exchanger 712 and heat-exchanged with a low-temperature aqueous solution to lower the temperature from 88 ° C. to 40 ° C.
  • the water-rich solution is supplied to the heat exchanger 713, heat-exchanged with the diluted draw solution at 40 ° C., cooled from 88 ° C. to 45 ° C., and then supplied to the final treatment unit 716.
  • permeated water is obtained at a flow rate of 67 L / h.
  • the draw solution separated from the permeated water is not considered because it is a small amount.
  • permeated water having a flow rate of 67 L / h can be obtained from the concentrated water having a flow rate of 100 L / h.
  • the regenerated draw solution supplied to the membrane module 711 is adjusted to a desired temperature by using an aqueous solution containing concentrated water or the like flowing from the outside.
  • the temperatures of the aqueous solution and the draw solution in the membrane module 711 can be brought close to each other, so that the processing in the membrane module 711 can be stabilized.
  • the diluted draw solution supplied to the separation tank 715 by the heater 714 is above the cloud point. It is heated to a temperature of 100 ° C. or lower.
  • the temperature range for raising the temperature when the diluted draw solution is heated by the heater 714 can be reduced, so that the energy required for heating by the heater 714 can be reduced, and the energy consumed for heating in the forward osmosis device 71 can be reduced. Can be reduced. Further, the temperature of the diluted draw solution and the regenerated draw solution is adjusted by heat exchange without branching the diluted draw solution into two flow paths. As a result, the balance of the flow rate in the flow path can be easily adjusted, so that the energy balance can be stabilized by suppressing the energy consumption required for cooling and heating while simplifying the piping structure.
  • FIG. 15 is a block diagram schematically showing a forward osmosis device according to the second device example.
  • the forward osmosis device 72 according to the second device example includes a membrane module 721 having a semipermeable membrane 721a inside, a heat exchanger 722,723,724, a heater 725, a separation tank 726, and a separation tank 726. It is configured to include a final processing unit 727.
  • the membrane module 721, the semipermeable membrane 721a, the heat exchanger 722, 723, the heater 725, the separation tank 726, and the final processing unit 727 in the forward osmosis apparatus 72 are the membranes in the forward osmosis apparatus 71 according to the first apparatus example, respectively. This is the same as the module 711, the semipermeable membrane 711a, the heat exchangers 712 and 713, the heater 714, the separation tank 715, and the final processing unit 716.
  • the flow direction of the regenerated draw solution is on the downstream side of the heat exchanger 723 along the flow direction of the diluted draw solution and on the upstream side of the heater 725.
  • a heat exchanger 724 is provided on the downstream side of the separation tank 726 and on the upstream side of the heat exchanger 722 along the above.
  • the intermediate heat exchange step is performed by the heat exchanger 724 as the intermediate heat exchange means. That is, in the forward osmosis treatment step according to the second apparatus example, the diluted draw solution flowing out from the membrane module 721 is heated by heat exchange with the high-temperature water-rich solution in the heat exchanger 723.
  • the heat exchanger 724 heat is exchanged between the water-rich solution and the regenerated draw solution having a temperature similar to that of the water-rich solution, and the temperature is raised. Then, the diluted draw solution is heated to a temperature above the cloud point and below 100 ° C. by the heater 725.
  • Other configurations are the same as those of the first apparatus example.
  • the regenerated draw solution having a temperature of 40 ° C. which has been heat-exchanged with concentrated water in the heat exchanger 722, is supplied to the membrane module 721, diluted, and flows out as a diluted draw solution.
  • the flow rate of the regenerated draw solution is 100 L / h.
  • the diluted draw solution flowing out of the membrane module 721 has a temperature of 40 ° C. and a flow rate of 167 L / h.
  • the diluted draw solution is then heated by the heat exchanger 723 to a temperature of 52 ° C. and then supplied to the heat exchanger 724.
  • the diluted draw solution is heated by heat exchange with the regenerated draw solution at 88 ° C. by the heat exchanger 724, heated to a temperature of 52 ° C. to 71 ° C., and then supplied to the heater 725 for further heating. The temperature is raised from ° C to 88 ° C.
  • the diluted draw solution is supplied to the separation tank 726 and phase-separated into the regenerated draw solution and the water-rich solution.
  • the regenerated draw solution has a temperature of 88 ° C. and a flow rate of 100 L / h.
  • the water-rich solution has a temperature of 88 ° C. and a flow rate of 67 L / h.
  • the regenerated draw solution is cooled from 88 ° C. to 63.5 ° C. by the heat exchanger 724 and then from 63.5 ° C. to 40 ° C. by the heat exchanger 722.
  • the water-rich solution is supplied to the final treatment unit 727 after being cooled from 88 ° C. to 45 ° C. by the heat exchanger 723.
  • permeated water is obtained at a flow rate of 67 L / h.
  • the draw solution separated from the permeated water is not considered because it is a small amount.
  • permeated water having a flow rate of 67 L / h can be obtained from the concentrated water having a flow rate of 100 L / h.
  • the same effect as that of the first device example can be obtained by performing heat exchange by the heat exchangers 722 and 723. Further, the heat exchanger 724 lowers the temperature of the regenerated draw solution to be supplied to the membrane module 721 while raising the temperature of the diluted draw solution to be supplied to the separation tank 726. With 725, the temperature range for raising the temperature when heating the diluted draw solution can be further reduced. Therefore, the energy required for heating by the heater 725 can be further reduced, and the energy consumed for heating in the forward osmosis apparatus 72 can be further reduced.
  • FIG. 15 shows a forward osmosis device 73 according to the third device example.
  • the forward osmosis device 73 according to the third device example includes a membrane module 731 having a semipermeable membrane 731a inside, a heat exchanger 732, 733, 734, a heater 735, a separation tank 736, and a separation tank 736. It is configured to include a final processing unit 737.
  • the membrane module 731, the semipermeable membrane 731a, the heat exchanger 732, 733, the heater 735, the separation tank 736, and the final processing unit 737 in the forward osmosis apparatus 73 are the membranes in the forward osmosis apparatus 71 according to the first apparatus example, respectively. This is the same as the module 711, the semipermeable membrane 711a, the heat exchangers 712 and 713, the heater 714, the separation tank 715, and the final processing unit 716.
  • a heat exchanger 734 is provided on the downstream side of the separation tank 736 and on the upstream side of the heat exchanger 732 along the above.
  • the pre-stage heat exchange step is performed by the heat exchanger 734 as the pre-stage heat exchange means. That is, in the forward osmosis treatment step according to the third apparatus example, the diluted draw solution flowing out from the membrane module 731 first exchanges heat with the high-temperature regenerated draw solution supplied from the separation tank 736 in the heat exchanger 734.
  • the concentrated water introduced from the outside into the forward osmosis apparatus 73 is heat-exchanged by the heat exchanger 732, and the concentrated water having a temperature of 40 ° C. is supplied to the membrane module 731.
  • the concentrated water concentrated by the membrane module 731 is discharged from the membrane module 731 at a flow rate of 33 L / h. That is, in the membrane module 731, water is moved at a flow rate of 67 L / h.
  • the regenerated draw solution having a temperature of 40 ° C. which has been heat-exchanged with concentrated water in the heat exchanger 732, is supplied to the membrane module 731, diluted, and flows out as a diluted draw solution.
  • the flow rate of the regenerated draw solution is 100 L / h.
  • the diluted draw solution flowing out of the membrane module 731 has a temperature of 40 ° C. and a flow rate of 167 L / h.
  • the diluted draw solution is heated by heat exchange with the 88 ° C. regenerated draw solution supplied from the separation tank 736 in the heat exchanger 734 to raise the temperature to 52 ° C., and then into the heat exchanger 733. Be supplied.
  • the diluted draw solution is heat-exchanged with the water-rich solution at 88 ° C. supplied from the separation tank 736 in the heat exchanger 733 to be heated to a temperature of 61 ° C., and then supplied to the heater 735 to be further heated.
  • the temperature is raised from 61 ° C to 88 ° C.
  • the diluted draw solution is supplied to the separation tank 736 and phase-separated into the regenerated draw solution and the water-rich solution.
  • the regenerated draw solution has a temperature of 88 ° C. and a flow rate of 100 L / h.
  • the water-rich solution has a temperature of 88 ° C. and a flow rate of 67 L / h.
  • the regenerated draw solution is cooled from 88 ° C. to 72.4 ° C. by the heat exchanger 734 and then from 72.4 ° C. to 40 ° C. by the heat exchanger 732.
  • the water-rich solution is supplied to the final treatment unit 737 after being cooled from 88 ° C. to 57 ° C. by the heat exchanger 733.
  • the heat resistance of the final treatment unit 737 is low, such as when a membrane treatment device is used as the final treatment unit 737, further cooling means (FIG. 6) is provided between the heat exchanger 733 and the final treatment unit 737.
  • the water-rich solution may be cooled to a predetermined temperature by installing (not shown).
  • permeated water can be obtained at a flow rate of 67 L / h.
  • the draw solution separated from the permeated water is not considered because it is a small amount.
  • permeated water having a flow rate of 67 L / h can be obtained from the concentrated water having a flow rate of 100 L / h.
  • the same effect as that of the first device example can be obtained by performing heat exchange by the heat exchangers 732 and 733. Further, the heat exchanger 734 lowers the temperature of the regenerated draw solution for supplying to the membrane module 731 while raising the temperature of the diluted draw solution, thereby obtaining the same effect as that of the second apparatus example. be able to.
  • FIG. 17 is a block diagram schematically showing the forward osmosis device 74 according to the fourth device example.
  • the forward osmosis device 74 according to the fourth device example includes a membrane module 741 having a semipermeable membrane 741a, heat exchangers 742a, 742b, 742c, a pretreatment unit 743, a heater 744, and a separation tank 745.
  • the membrane module 741, the semipermeable membrane 741a, the heat exchangers 742a, 742b, 742c, the heater 744, the separation tank 745, and the final processing unit 746 in the forward osmosis apparatus 74 are each in the forward osmosis apparatus 72 according to the second apparatus example.
  • the pretreatment unit 743 as the pretreatment means is provided on the upstream side of the membrane module 741 along the flow direction of the aqueous solution.
  • the pretreatment unit 743 performs a treatment for removing impurities such as turbidity contained in the aqueous solution before introducing the aqueous solution supplied from the outside into the membrane module 741.
  • a conventionally known pretreatment device such as sand filtration or a pretreatment membrane such as an MF membrane or a UF membrane can be adopted.
  • the heat exchanger 742a is located on the upstream side of the membrane module 741 along the flow direction of the aqueous solution, and on the downstream side of the separation tank 745 along the flow direction of the regenerated draw solution that is discharged from the separation tank 745 and reused. It is provided in.
  • the heat exchanger 742a exchanges heat between the regenerated draw solution flowing out of the separation tank 745 and the aqueous solution containing water supplied from the outside.
  • thermometer 747a as the aqueous solution temperature measuring means is at least upstream of the film module 741 along the flow direction of the aqueous solution, and in the fourth apparatus example, upstream of the pretreatment unit 743 and the heat exchanger 742a. It is provided on the downstream side.
  • the thermometer 747a measures the temperature of the aqueous solution containing heat exchanged by the heat exchanger 742a, and supplies the measured value of the temperature to the control unit 750.
  • thermometer 747b as the draw solution temperature measuring means is at least upstream of the membrane module 741 along the flow direction of the regenerated draw solution and downstream of the heat exchanger 742a along the flow direction of the regenerated draw solution. Provided.
  • the thermometer 747b measures the temperature of the regenerated draw solution heat-exchanged by the heat exchanger 742a, and supplies the measured value of the temperature to the control unit 750.
  • the flow meter 748 as a flow rate measuring means is provided at least on the upstream side of the membrane module 741 along the flow direction of the aqueous solution.
  • the flow meter 748 measures the flow rate of the aqueous solution containing water flowing into the membrane module 741 and supplies the measured value of the flow rate to the control unit 750.
  • the control valve 749a is provided at least on the upstream side of the membrane module 741 along the flow direction of the aqueous solution, on the upstream side of the pretreatment unit 743 and on the downstream side of the heat exchanger 742a in the fourth device example.
  • the control valve 749a is a forward osmosis flow rate adjusting means for adjusting the flow rate of the aqueous solution flowing into the pretreatment unit 743 and the flow rate of the aqueous solution flowing into the membrane module 741.
  • the opening degree of the control valve 749a is controlled by the control unit 750 based on the measured value of the flow rate of the aqueous solution contained by the flow meter 748 and the measured value of the temperature by the thermometers 747a and 747b.
  • the opening degree of the control valve 749a is adjusted by the control unit 750 so that the flow rate of the aqueous solution containing water flowing into the pretreatment unit 743 becomes constant and the flow rate of the aqueous solution containing water flowing into the membrane module 741 becomes constant. Will be done.
  • the control valve 749b as the heat exchange flow rate adjusting means is provided in the bypass pipe as the bypass means.
  • the bypass pipe is configured to communicate with the heat exchanger 742c from the upstream side to the downstream side along the flow direction of the diluted draw solution so that the diluted draw solution can pass through. Thereby, by adjusting the opening degree of the control valve 749b, the flow rate of the diluted draw solution passing through the heat exchanger 742c as the intermediate heat exchange means can be adjusted.
  • the opening degree of the control valve 749b is 0 and the control valve 749b is fully closed, the entire amount of the diluted draw solution flowing out from the membrane module 741 passes through the heat exchanger 742c.
  • the opening degree of the control valve 749b is maximum and the control valve 749b is fully opened, the diluted draw solution flowing out from the membrane module 741 passes through the control valve 749b in an amount that can flow into the bypass pipe. In this case, the flow rate of the diluted draw solution passing through the heat exchanger 742c is minimized. In this way, the flow rate of the diluted draw solution to be heat-exchanged in the heat exchanger 742c can be adjusted according to the opening degree of the control valve 749b. Thereby, the temperature of the regenerated draw solution flowing out from the separation tank 745 can be adjusted according to the opening degree of the control valve 749b.
  • thermometer 747b It is desirable to adjust the temperature of the regenerated draw solution so that the temperature measured by the thermometer 747b is substantially constant, specifically, for example, about 40 ° C.
  • the opening degree of the control valve 749b so that the temperature of the regenerated draw solution supplied to the membrane module 741 is kept substantially constant at a predetermined temperature, heat exchange is performed in the entire forward osmosis device 74. Since the efficiency can be improved and the amount of waste of the aqueous solution contained through the control valve 749a can be reduced, the energy required for sending the blowdown water can be reduced.
  • the control unit 750 as a control means can use a device called a sequencer. Physically, it is an electronic circuit mainly composed of a well-known microcomputer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an interface.
  • the control unit 750 performs a calculation using the data input to the RAM and the data stored in the ROM or the like in advance, and outputs the calculation result as a command signal.
  • the control unit 750 loads the program held in the ROM into the RAM and executes it in the CPU to operate various devices of the normal penetration device 74 based on the control of the CPU, and also in the RAM or ROM as a recording unit. Reads data and writes to RAM.
  • the control unit 750 inputs the data of the measured values from the thermometers 747a and 747b and the flow meter 748, and controls the opening degree of the control valves 749a and 749b.
  • the forward osmosis treatment step using the forward osmosis apparatus 74 according to the fourth apparatus example will be described.
  • the forward osmosis treatment step according to the fourth apparatus example the forward osmosis step, the heating step, the water separation step, the outflow side heat exchange step, and the final treatment step are the same as those in the first apparatus example.
  • the pretreatment step is performed. That is, in the pretreatment unit 743, a treatment for removing impurities such as turbidity contained in the aqueous solution is performed on the aqueous solution supplied from the outside. The aqueous solution containing the pretreatment step is supplied to the membrane module 741.
  • the inflow side heat exchange step is performed by the heat exchanger 742a, the control valve 749b, and the control unit 750 as the inflow side heat exchange means. That is, the aqueous solution contained in the forward osmosis device 74 supplied from the outside is first supplied to the heat exchanger 742a.
  • the heat exchanger 742a is supplied with the regenerated draw solution that has flowed out of the separation tank 745 and passed through the heat exchanger 742c.
  • the heat exchanger 742a adjusts the temperatures of the regenerated draw solution and the aqueous solution-containing solution to a predetermined temperature, for example, about 40 ° C.
  • the inflow side heat exchange step of adjusting the temperature of the aqueous solution and the regenerated draw solution to a predetermined temperature in the fourth apparatus example will be described.
  • thermometer 747b the temperature on the downstream side of the heat exchanger 742a along the flow direction of the regenerated draw solution is measured by a thermometer 747b.
  • the measured value of the measured temperature is supplied to the control unit 750.
  • the thermometer 747a measures the temperature on the downstream side of the heat exchanger 742a along the flow direction of the aqueous solution.
  • the measured value of the measured temperature is supplied to the control unit 750.
  • the control unit 750 performs an intermediate heat exchange step based on the result of comparing the measured values supplied from the thermometers 747a and 747b with the predetermined temperature when the temperature is supplied to the preset membrane module 741.
  • a heat exchange flow rate adjusting step for adjusting the flow rate of the module is performed.
  • heat exchange flow rate adjustment process and intermediate heat exchange process In the heat exchanger 742c, an intermediate heat exchange step is performed in which heat exchange is performed between the diluted draw solution and the regenerated draw solution.
  • the control unit 750 performs a heat exchange flow rate adjusting step for adjusting the control valve 749b based on the measured values of the temperature supplied from the thermometers 747a and 747b to the control unit 750.
  • the control unit 750 adjusts the control valve 749a based on the measured value of the temperature supplied from the thermometers 747a and 747b to the control unit 750, if necessary.
  • control unit 750 controls the opening degrees of the control valves 749a and 749b, respectively, so that the temperatures measured by the thermometers 747a and 747b are maintained substantially constant. Further, the opening degrees of the control valves 749a and 749b are independently controlled by the control unit 750.
  • a control method for controlling the opening degree of the control valves 749a and 749b so as to maintain the temperature measured by the thermometers 747a and 747b substantially constant will be described.
  • the control method of the control valves 749a and 749b is not limited to the following method.
  • the control unit 750 controls to lower the temperature of the regenerated draw solution passing through the heat exchanger 742a. In this case, the control unit 750 reduces the flow rate of the diluted draw solution flowing through the bypass pipe by reducing the opening degree of the control valve 749b. Along with this, the flow rate of the diluted draw solution flowing through the heat exchanger 742c increases, and the amount of heat transferred from the regenerated draw solution to the diluted draw solution in the heat exchanger 742c increases.
  • the temperature of the regenerated draw solution passing through the heat exchanger 742a is lowered as compared with that before the opening degree of the control valve 749b is reduced, and the temperature rise of the aqueous solution-containing solution is also suppressed.
  • the control unit 750 controls to raise the temperature of the regenerated draw solution passing through the heat exchanger 742a. That is, the control unit 750 increases the flow rate of the diluted draw solution flowing through the bypass pipe by increasing the opening degree of the control valve 749b. Along with this, the flow rate of the diluted draw solution flowing through the heat exchanger 742c is reduced, and the amount of heat transferred from the regenerated draw solution to the diluted draw solution in the heat exchanger 742c is reduced. As a result, the temperature of the regenerated draw solution passing through the heat exchanger 742a rises as compared with that before the opening degree of the control valve 749b is reduced, and the temperature of the aqueous solution containing water also rises.
  • the heat exchanger 742a is supplied with a regenerated draw solution having a lower temperature than when the control valve 749b is fully open. To. At this time, since the amount of the aqueous solution supplied to the heat exchanger 742a in order to lower the temperature of the regenerated draw solution may be relatively small, in order to keep the aqueous solution supplied to the pretreatment unit 743 and the membrane module 741 constant. The amount of waste from the control valve 749a is reduced.
  • the control valve 749b when the control valve 749b is fully open or relatively open, the temperature of the regenerated draw solution supplied to the heat exchanger 742a is higher than when the control valve 749b is fully closed. At this time, in order to cool the regenerated draw solution and maintain the temperature of the aqueous solution contained by the thermometer 747a at a predetermined temperature, it is necessary to increase the amount of the aqueous solution supplied to the heat exchanger 742a. The amount of waste from valve 749a increases.
  • the opening degree of the control valve 747b is adjusted so that the temperature measured by the thermometer 747b is maintained at a predetermined temperature, for example, 40 ° C., and the temperature of the thermometer 747a is adjusted, for example, at a predetermined temperature.
  • the opening degree of the control valve 749b is adjusted so as to maintain the temperature at 40 ° C.
  • the temperature is further adjusted by adjusting the opening degree of the control valve 749a. Adjust the measured values of 747a and 747b so that they are both constant.
  • control unit 750 controls the opening degree of the control valves 749a and 749b based on the measured values of the thermometers 747a and 747b, so that the temperature of the aqueous solution and the temperature of the regenerated draw solution are substantially equal to each other. It is controlled to reach a predetermined temperature at the same temperature.
  • the regenerated draw solution that has been heated by heat exchange in the heat exchanger 742a is supplied to the other chamber of the membrane module 741, and the aqueous solution that has been heated by heat exchange is supplied to the pretreatment unit 743. It is fed and the turbidity is removed.
  • the aqueous solution flowing out of the pretreatment unit 743 passes through the flow meter 748 and is supplied to one chamber of the membrane module 741. Since the temperature of the aqueous solution containing water before being supplied to the membrane module 741 is raised, the amount of permeated water (m / day) of the membrane module 741 can be improved. Further, by keeping the temperature of the aqueous solution supplied to the membrane module 741 constant, the amount of permeated water in the membrane module 741 can be stabilized.
  • a forward osmosis flow rate adjusting step of adjusting the flow rate of the aqueous solution containing water flowing into the membrane module 741 is further performed by the flow meter 748, the control valve 749a, and the control unit 750.
  • the aqueous solution supplied from the outside to the forward osmosis device 74 is supplied to the membrane module 741 after the turbidity is removed by the pretreatment unit 743 via the heat exchanger 742a.
  • the flow meter 748 measures the flow rate on the upstream side of the membrane module 741 along the flow direction of the aqueous solution, and supplies the measured value to the control unit 750.
  • the control unit 750 compares the measured value supplied from the flow meter 748 with the predetermined flow rate when supplying to the preset membrane module 741. When the measured value is larger than the predetermined flow rate, the control unit 750 controls to reduce the flow rate of the aqueous solution containing water flowing into the membrane module 741.
  • control unit 750 increases the flow rate of the aqueous solution containing water to be discarded to the outside on the upstream side of the pretreatment unit 743 by increasing the opening degree of the control valve 749a. As a result, the flow rate of the aqueous solution supplied to the pretreatment unit 743 is reduced, and the flow rate of the aqueous solution supplied to the membrane module 741 is reduced. On the contrary, when the measured value is smaller than the predetermined flow rate, the control unit 750 controls to increase the flow rate of the aqueous solution containing the aqueous solution flowing into the membrane module 741.
  • control unit 750 reduces the flow rate of the aqueous solution containing water to be discarded to the outside on the upstream side of the pretreatment unit 743 by reducing the opening degree of the control valve 749a.
  • the flow rate of the aqueous solution supplied to the pretreatment unit 743 is increased, and the flow rate of the aqueous solution supplied to the membrane module 741 is increased. Therefore, the flow rate of the aqueous solution containing water flowing into the membrane module 741 can be maintained at a substantially constant predetermined flow rate.
  • heat exchange is performed by the heat exchanger 742a with respect to the blowdown water introduced from the outside into the forward osmosis device 74.
  • the blowdown water is heated to a temperature of 40 ° C. by the heat exchanger 742a and supplied to the pretreatment unit 743 and the membrane module 741.
  • the opening degree of the control valve 749b is controlled according to the temperature on the upstream side of the pretreatment unit 743 and the downstream side of the heat exchanger 742a along the flow direction of the aqueous solution, and passes through the heat exchanger 742c.
  • the flow rate of the diluted draw solution is controlled.
  • the amount of heat transferred from the regenerated draw solution to the diluted draw solution is controlled in the heat exchanger 742c, the temperature of the regenerated draw solution passing through the heat exchanger 742a is controlled, and the regenerated draw solution is transferred to the blowdown water.
  • the amount of heat is controlled.
  • the blowdown water concentrated by the membrane module 741 is discharged from the membrane module 741 at a flow rate of 33 L / h. That is, in the membrane module 741, water is moved at a flow rate of 67 L / h.
  • the temperature of the regenerated draw solution is adjusted by heat exchange with the blowdown water in the heat exchanger 742a, and the temperature is lowered to 40 ° C.
  • the regenerated draw solution is supplied to the membrane module 741 to be diluted and discharged as a diluted draw solution.
  • the flow rate of the regenerated draw solution is 100 L / h.
  • the diluted draw solution flowing out of the membrane module 741 has a temperature of 40 ° C. and a flow rate of 167 L / h.
  • the diluted draw solution is heated by heat exchange with the water-rich solution having a temperature of 88 ° C. in the heat exchanger 742b, and the temperature is raised from 40 ° C. to 52 ° C.
  • the diluted draw solution is supplied to the heat exchanger 742c for heat exchange.
  • the temperature of the diluted draw solution is controlled from 52 ° C. according to the opening degree of the control valve 749b, which is controlled according to the temperature on the upstream side of the membrane module 741 along the flow direction of the aqueous solution.
  • the temperature is raised to 52 ° C. or higher and 71 ° C. or lower. After that, it is supplied to the heater 744 and further heated to raise the temperature to 88 ° C.
  • the diluted draw solution is supplied to the separation tank 745 and phase-separated into the regenerated draw solution and the water-rich solution.
  • the regenerated draw solution flowing out of the separation tank 745 has a temperature of 88 ° C. and a flow rate of 1000 L / h.
  • the regenerated draw solution is supplied to the heat exchanger 742c to exchange heat with the low temperature diluted draw solution.
  • the temperature of the heat exchange in the heat exchanger 742c is controlled according to the opening degree of the control valve 749b, and the temperature is lowered from 88 ° C. to a temperature of 65 ° C. or higher and lower than 88 ° C.
  • the water-rich solution flowing out of the separation tank 745 has a temperature of 88 ° C. and a flow rate of 67 L / h.
  • the water-rich solution is supplied to the heat exchanger 742b for heat exchange with the diluted draw solution at 40 ° C., cooled from 88 ° C. to 45 ° C., and then supplied to the final treatment unit 746.
  • permeated water is obtained at a flow rate of 67 L / h.
  • the draw solution separated from the permeated water is not considered because it is a small amount.
  • permeated water having a flow rate of 67 L / h can be obtained from the blow-down water having a flow rate of 100 L / h.
  • a control valve 749b for adjusting the flow rate of the bypass pipe that bypasses the upstream side and the downstream side along the flow direction of the diluted draw solution in the heat exchanger 742c is provided, and a membrane is provided.
  • the opening degree of the control valve 749b according to the temperature of the aqueous solution flowing into the module 741, the heat exchange between the aqueous solution and the regenerated draw solution is controlled, so that the membrane module 741 is supplied.
  • the aqueous solution and the regenerated draw solution are adjusted to the desired temperature.
  • the temperatures of the aqueous solution and the draw solution in the membrane module 741 can be made extremely close to each other, so that the processing efficiency in the membrane module 741 can be stabilized.
  • control valve 749a is provided at least on the upstream side of the membrane module 741 along the flow direction of the aqueous solution, and the opening degree of the control valve 749a is adjusted according to the flow rate on the upstream side of the membrane module 741. Therefore, the aqueous solution supplied to the membrane module 741 can be maintained at a predetermined flow rate. Thereby, the processing efficiency in the membrane module 741 can be further stabilized.
  • the forward penetration device 74 may be configured without the heat exchanger 742b. That is, in the forward osmosis apparatus 74, a configuration in which heat exchange is not performed between the diluted draw solution and the water-rich solution is also possible. Further, in the forward osmosis device 74, the forward osmosis device 74 may be configured not to be provided with the pretreatment unit 743 or to be provided with neither the pretreatment unit 743 nor the heat exchanger 742b. In this case, a pretreatment for removing turbidity or the like from the aqueous solution is executed in the pre-stage of being introduced into the forward osmosis apparatus 74.
  • the present invention is not limited to the above-described embodiments, and various modifications based on the technical idea of the present invention are possible.
  • the numerical values given in the above-described embodiment are merely examples, and different numerical values may be used if necessary, and the present invention is based on the description and drawings which form a part of the disclosure of the present invention according to the present embodiment. Is not limited.
  • PAC is used as the silica flocculant, but a flocculant other than PAC can also be used, and sludge S precipitated in the reaction vessel can be used as the flocculant.
  • aluminum salts such as aluminum hydroxide (Al (OH) 3 ) and aluminum sulfate (Al 2 (SO 4 ) 3 ), such as Mg (OH) 2 and magnesium chloride (MgCl 2 ).
  • magnesium salts such as ferric chloride (FeCl 3 ), ferrous sulfate (Fe 2 (SO 4 ) 3 ), iron salts such as polysilica iron (PSI), and polymer flocculants such as polyacrylamides.
  • FeCl 3 ferric chloride
  • Fe 2 (SO 4 ) 3 ferrous sulfate
  • PSI polysilica iron
  • polymer flocculants such as polyacrylamides.
  • the water treatment devices 1 to 8 according to the first to fourth embodiments and the first to fourth modifications described above can be appropriately combined.
  • the present invention is suitable for application to a zero drainage process.
  • Second filtration unit 70 , 71, 72, 73, 74 Forward osmosis device 80 Distillation crystallization section 90

Landscapes

  • Engineering & Computer Science (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Organic Chemistry (AREA)
  • Nanotechnology (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Separation Of Suspended Particles By Flocculating Agents (AREA)

Abstract

The purpose of the present invention is to improve water recovery rate while suppressing generation of scale in the case of extracting water from treatment-target water including impurities. This water treatment device is provided with: a plurality of flocculation and sedimentation parts that flocculate and eliminate at least a portion of impurities from treatment-target water; and a plurality of water extraction parts that each have a forward osmosis membrane and/or a reverse osmosis membrane capable of extracting water from a water-containing solution, containing water as a solvent, so as to extract permeable water from the treatment-target water, and that also discharge concentrated water obtained as a result of extraction of the permeable water from the treatment-target water. Along the flow direction of the treatment-target water, a first water extraction part is disposed at the stage after a first flocculation and sedimentation part, a second flocculation and sedimentation part is disposed at the stage after the first water extraction part, and a second water extraction part is disposed at the stage after the second flocculation and sedimentation part. The second water extraction part extracts permeable water from the concentrated water discharged from the first water extraction part, and discharges highly concentrated water which is obtained by further concentrating the concentrated water discharged from the first water extraction part, whereas the first flocculation and sedimentation part and the second flocculation and sedimentation part flocculate and eliminate at least a portion of silica.

Description

水処理装置および水処理方法Water treatment equipment and water treatment method
　本発明は、水処理装置および水処理方法に関する。 The present invention relates to a water treatment apparatus and a water treatment method.
　近年、工場などからの排水量を減容させる技術が提案されている。具体的に、逆浸透膜（ＲＯ膜）などを用いて排水を濃縮して透過水を回収し、排水を減容化する方法などが提案されている。排水を減容する方法として、ＲＯ膜により濃縮された濃縮水をさらに蒸留または晶析させる方法によって、固形分以外の廃棄物を極力発生させないゼロ排水プロセス（ＺＬＤ：Zero　Liquid　Discharge）が知られている。 In recent years, techniques for reducing the amount of wastewater from factories have been proposed. Specifically, a method of concentrating wastewater using a reverse osmosis membrane (RO membrane) or the like to recover permeated water and reducing the volume of wastewater has been proposed. As a method for reducing the volume of wastewater, a zero wastewater process (ZLD: Zero Liquid Discharge) that does not generate waste other than solid content as much as possible by further distilling or crystallizing the concentrated water concentrated by the RO membrane is known. There is.
　ところで、ＲＯ膜などの膜を用いて水処理を行う過程における濃縮に伴って、膜の内部で溶解度を超えてしまうと、塩類が析出する、いわゆるスケーリングが生じ、膜の閉塞の原因になる。スケーリングは溶解度の低い塩類が原因であって、スケーリングが発生すると、膜の水透過性の低下や原水の供給側における圧力損失の上昇を引き起こし、水処理装置の運転の継続が困難になる。スケーリングを発生させる塩類は溶解度の低い成分である。 By the way, if the solubility is exceeded inside the membrane due to concentration in the process of water treatment using a membrane such as an RO membrane, so-called scaling occurs in which salts are precipitated, which causes clogging of the membrane. Scaling is caused by low-solubility salts, and when scaling occurs, it causes a decrease in water permeability of the membrane and an increase in pressure loss on the supply side of raw water, making it difficult to continue the operation of the water treatment apparatus. Salts that cause scaling are components with low solubility.
　非特許文献１には、凝集沈殿によってカルシウムをある程度除去した後に軟水器によってカルシウムを完全に除去し、さらにＲＯ膜によって被処理水をアルカリ性にした環境で運転することによって、シリカのスケーリングを抑制する方法が開示されている。非特許文献１に記載の技術は、Ｃａ系のスケールやシリカのスケールを抑制する水処理装置として用いられている。 In Non-Patent Document 1, the scaling of silica is suppressed by removing calcium to some extent by coagulation precipitation, completely removing calcium by a water softener, and operating in an environment in which the water to be treated is made alkaline by an RO membrane. The method is disclosed. The technique described in Non-Patent Document 1 is used as a water treatment apparatus that suppresses Ca-based scale and silica scale.
米国特許出願公開第２０１４／１５１２９５号明細書US Patent Application Publication No. 2014/151295 国際公開第２０１５／００２３０９号International Publication No. 2015/002309 特開２０２０－０１８９９２号公報Japanese Unexamined Patent Publication No. 2020-018992 特開２０２０－０５８９６３号公報Japanese Unexamined Patent Publication No. 2020-058963
　上述した特許文献１および非特許文献１に開示された従来技術による水処理方法においては、スケールの発生をある程度抑制することが可能になるが、特にＺＬＤにおいては、従来に比して大幅に高い濃縮を実現して水の回収率の向上が望まれていた。この要請は、ＺＬＤ以外の濃縮排水が生じる排水プロセスにおいても同様に求められ、スケールの発生を抑制しつつ濃縮排水をさらに濃縮させて、被処理水から回収する水の回収率を向上させる技術が求められていた。 In the water treatment method according to the prior art disclosed in Patent Document 1 and Non-Patent Document 1 described above, it is possible to suppress the generation of scale to some extent, but especially in ZLD, it is significantly higher than in the prior art. It has been desired to realize concentration and improve the water recovery rate. This requirement is also required for wastewater processes that generate concentrated wastewater other than ZLD, and a technique for further concentrating concentrated wastewater while suppressing the generation of scale to improve the recovery rate of water recovered from the water to be treated. I was asked.
　本発明は、上記に鑑みてなされたものであって、その目的は、不純物を含む被処理水から水を抽出する場合に、スケールの発生を抑制しつつ水の回収率を向上できる水処理装置および水処理方法を提供することにある。 The present invention has been made in view of the above, and an object of the present invention is a water treatment apparatus capable of improving the water recovery rate while suppressing the generation of scale when extracting water from water to be treated containing impurities. And to provide a water treatment method.
　上述した課題を解決し、目的を達成するために、本発明の一態様に係る水処理装置は、シリカを含有した不純物を含む被処理水から水を抽出する水処理装置であって、前記被処理水から前記不純物の少なくとも一部を凝集させて除去する複数の凝集沈殿部と、溶媒として水を含む含水溶液から水を抽出可能な正浸透膜および逆浸透膜の少なくとも一方を有して前記被処理水から透過水を抽出するとともに、前記被処理水から前記透過水が抽出されて得られた濃縮水を排出する複数の水抽出部と、を備え、前記被処理水の流れ方向に沿って、前記複数の凝集沈殿部のうちの一部である第１凝集沈殿部の後段に前記複数の水抽出部のうちの一部である第１水抽出部と、前記第１水抽出部の後段に前記複数の凝集沈殿部のうちの他部である第２凝集沈殿部と、前記第２凝集沈殿部の後段に前記複数の水抽出部のうちの他部である第２水抽出部とが設けられ、前記第１凝集沈殿部は、前記被処理水から前記シリカの一部を除去した後、前記被処理水を前記第１水抽出部に供給し、前記第１水抽出部は、前記シリカの一部が除去された前記被処理水から前記透過水を抽出するとともに前記濃縮水を排出して、前記濃縮水を前記第２凝集沈殿部に供給し、前記第２凝集沈殿部は、前記濃縮水から前記シリカの残部を除去した後、前記濃縮水を前記第２水抽出部に供給し、前記第２水抽出部は、前記正浸透膜および前記逆浸透膜の少なくとも一方を有し、前記第２凝集沈殿部から供給された前記濃縮水から透過水を抽出するとともに、前記濃縮水をさらに濃縮した高濃縮水を排出することを特徴とする。 In order to solve the above-mentioned problems and achieve the object, the water treatment apparatus according to one aspect of the present invention is a water treatment apparatus that extracts water from water to be treated containing impurities containing silica, and is the subject. It has at least one of a normal osmotic film and a back permeable film capable of extracting water from a water-containing aqueous solution containing water as a solvent, and having a plurality of agglomerated sedimentation portions for aggregating and removing at least a part of the impurities from the treated water. It is provided with a plurality of water extraction units for extracting the permeated water from the water to be treated and discharging the concentrated water obtained by extracting the permeated water from the water to be treated, along the flow direction of the water to be treated. A first water extraction unit, which is a part of the plurality of water extraction units, and a first water extraction unit, which are a part of the plurality of water extraction units, are placed after the first aggregation and sedimentation unit, which is a part of the plurality of coagulation and sedimentation units. The second coagulation sedimentation part, which is another part of the plurality of coagulation sedimentation portions, is in the latter stage, and the second water extraction part, which is the other part of the plurality of water extraction parts, is in the rear stage of the second coagulation sedimentation portion. Is provided, the first coagulation sedimentation section removes a part of the silica from the water to be treated, and then supplies the water to be treated to the first water extraction section. The permeated water is extracted from the water to be treated from which a part of the silica has been removed, the concentrated water is discharged, and the concentrated water is supplied to the second coagulation sedimentation portion. After removing the balance of the silica from the concentrated water, the concentrated water is supplied to the second water extraction unit, and the second water extraction unit has at least one of the normal permeable membrane and the back permeable membrane. Then, the permeated water is extracted from the concentrated water supplied from the second coagulation sedimentation portion, and the highly concentrated water obtained by further concentrating the concentrated water is discharged.
　本発明の一態様に係る水処理装置は、上記の発明において、前記被処理水または前記濃縮水のろ過を行うろ過部が複数設けられ、前記被処理水の流れ方向に沿って、前記第１凝集沈殿部の後段かつ前記第１水抽出部の前段に、前記複数のろ過部の一部である第１ろ過部が設けられ、前記第２凝集沈殿部の後段かつ前記第２水抽出部の前段に、前記複数のろ過部の他部である第２ろ過部が設けられていることを特徴とする。 In the above invention, the water treatment apparatus according to one aspect of the present invention is provided with a plurality of filtration units for filtering the water to be treated or the concentrated water, and the first one is provided along the flow direction of the water to be treated. A first filtration section, which is a part of the plurality of filtration sections, is provided after the coagulation sedimentation section and before the first water extraction section, and is after the second coagulation sedimentation section and in the second water extraction section. A second filtration unit, which is another portion of the plurality of filtration units, is provided in the previous stage.
　本発明の一態様に係る水処理装置は、上記の発明において、前記第１ろ過部に供給される前記被処理水、および前記第２ろ過部に供給される前記濃縮水のｐＨを、４以上８以下に調整可能に構成されていることを特徴とする。 In the above invention, the water treatment apparatus according to one aspect of the present invention has a pH of 4 or more for the water to be treated supplied to the first filtration unit and the concentrated water supplied to the second filtration unit. It is characterized in that it is configured to be adjustable to 8 or less.
　本発明の一態様に係る水処理装置は、上記の発明において、前記第１水抽出部が、低圧逆浸透膜を有する低圧逆浸透部からなるとともに、前記第２水抽出部が、高圧逆浸透膜を有する高圧逆浸透部または前記正浸透膜を有する正浸透部からなることを特徴とする。 In the water treatment apparatus according to one aspect of the present invention, in the above invention, the first water extraction unit is composed of a low pressure reverse osmosis unit having a low pressure reverse osmosis membrane, and the second water extraction unit is a high pressure reverse osmosis unit. It is characterized by comprising a high-pressure reverse osmosis portion having a membrane or a forward osmosis portion having the forward osmosis membrane.
　本発明の一態様に係る水処理装置は、上記の発明において、前記第２水抽出部の後段に、前記高濃縮水に対して蒸留処理および晶析処理の少なくとも一方の処理を行って精製水を排出する蒸留晶析部が設けられていることを特徴とする。 In the above invention, the water treatment apparatus according to one aspect of the present invention is purified water obtained by subjecting the highly concentrated water to at least one of distillation treatment and crystallization treatment in the subsequent stage of the second water extraction unit. It is characterized in that a distillation crystallization unit for discharging water is provided.
　本発明の一態様に係る水処理装置は、上記の発明において、前記不純物がカルシウムを含み、前記被処理水の流れ方向に沿って、前記第１凝集沈殿部の後段かつ前記第１水抽出部の前段と、前記第２凝集沈殿部の後段かつ前記第２水抽出部の前段との少なくとも一方に、前記カルシウムを除去可能なカルシウム除去部が設けられていることを特徴とする。 In the water treatment apparatus according to one aspect of the present invention, in the above invention, the impurities contain calcium, and the first water extraction unit is located after the first coagulation sedimentation unit along the flow direction of the water to be treated. A calcium removing portion capable of removing the calcium is provided at least one of the front stage of the above and the rear stage of the second coagulation sedimentation portion and the front stage of the second water extraction portion.
　本発明の一態様に係る水処理装置は、上記の発明において、前記不純物がカルシウムを含み、前記被処理水の流れ方向に沿った前記第１水抽出部の前段における前記被処理水にカルシウム分散剤を添加可能に構成されていることを特徴とする。 In the water treatment apparatus according to one aspect of the present invention, in the above invention, the impurities contain calcium, and calcium is dispersed in the water to be treated in the previous stage of the first water extraction unit along the flow direction of the water to be treated. It is characterized in that it is configured so that an agent can be added.
　本発明の一態様に係る水処理装置は、上記の発明において、前記凝集沈殿部において前記シリカを凝集させる凝集剤が、ポリ塩化アルミニウムまたは塩化アルミニウムと、前記被処理水にポリ塩化アルミニウムまたは塩化アルミニウムが添加されて前記凝集沈殿部に沈殿された凝集沈殿汚泥と、を含むことを特徴とする。 In the water treatment apparatus according to one aspect of the present invention, in the above invention, the flocculant that aggregates the silica in the coagulation sedimentation portion is polyaluminum chloride or aluminum chloride, and the water to be treated is polyaluminum chloride or aluminum chloride. Is added and settled in the coagulation sedimentation portion, and the coagulation sedimentation sludge is contained.
　本発明の一態様に係る水処理装置は、上記の発明において、前記不純物がマグネシウムを含むことを特徴とする。 The water treatment apparatus according to one aspect of the present invention is characterized in that, in the above invention, the impurity contains magnesium.
　本発明の一態様に係る水処理方法は、シリカを含有した不純物を含む被処理水から水を抽出する水処理方法であって、前記被処理水に対して、前記不純物に含まれる前記シリカの一部を凝集させて除去する第１凝集沈殿工程と、前記第１凝集沈殿工程の後に、正浸透膜および逆浸透膜の少なくとも一方によって前記被処理水から透過水を抽出するとともに、前記被処理水から前記透過水を抽出して得られた濃縮水を排出する第１水抽出工程と、前記第１水抽出工程の後に、前記濃縮水に対して前記不純物に含まれる前記シリカの残部を凝集させて除去する第２凝集沈殿工程と、前記第２凝集沈殿工程の後に、正浸透膜および逆浸透膜の少なくとも一方によって前記濃縮水から透過水を抽出するとともに、前記濃縮水をさらに濃縮した高濃縮水を排出する第２水抽出工程と、を含むことを特徴とする。 The water treatment method according to one aspect of the present invention is a water treatment method for extracting water from water to be treated containing impurities containing silica, and the silica contained in the impurities with respect to the water to be treated. After the first coagulation-sedimentation step of coagulating and removing a part of the water, and the first coagulation-precipitation step, the permeated water is extracted from the water to be treated by at least one of a normal osmotic film and a back-permeation film, and the water to be treated is treated. After the first water extraction step of extracting the permeated water from water and discharging the concentrated water obtained, and the first water extraction step, the balance of the silica contained in the impurities is aggregated with respect to the concentrated water. After the second coagulation-precipitation step and the second coagulation-precipitation step, the permeated water is extracted from the concentrated water by at least one of a normal osmotic membrane and a back-penetrating membrane, and the concentrated water is further concentrated. It is characterized by including a second water extraction step of discharging concentrated water.
　本発明の一態様に係る水処理方法は、上記の発明において、前記第１凝集沈殿工程および前記第２凝集沈殿工程において、前記被処理水のｐＨを、８以上１２以下に調整することを特徴とする。 The water treatment method according to one aspect of the present invention is characterized in that, in the above invention, the pH of the water to be treated is adjusted to 8 or more and 12 or less in the first coagulation / precipitation step and the second coagulation / precipitation step. And.
　本発明の一態様に係る水処理方法は、上記の発明において、前記第１凝集沈殿工程の後かつ前記第１水抽出工程の前に、前記被処理水をろ過する第１ろ過工程と、前記第２凝集沈殿工程の後かつ前記第２水抽出工程の前に、前記濃縮水をろ過する第２ろ過工程と、を含むことを特徴とする。 In the above invention, the water treatment method according to one aspect of the present invention includes the first filtration step of filtering the water to be treated and the first filtration step after the first coagulation sedimentation step and before the first water extraction step. It is characterized by including a second filtration step of filtering the concentrated water after the second coagulation sedimentation step and before the second water extraction step.
　本発明の一態様に係る水処理方法は、この構成において、前記第１ろ過工程における前記被処理水のｐＨを４以上８以下に調整し、前記第２ろ過工程における前記濃縮水のｐＨを４以上８以下に調整することを特徴とする。 In this configuration, the water treatment method according to one aspect of the present invention adjusts the pH of the water to be treated in the first filtration step to 4 or more and 8 or less, and adjusts the pH of the concentrated water in the second filtration step to 4. It is characterized by adjusting to 8 or less.
　本発明の一態様に係る水処理方法は、上記の発明において、前記第１水抽出工程が、低圧逆浸透膜によって前記透過水を抽出する低圧逆浸透工程を含むとともに、前記第２水抽出工程が、高圧逆浸透膜によって前記透過水を抽出する高圧逆浸透工程、または前記正浸透膜によって前記透過水を抽出する正浸透工程を含むことを特徴とする。 In the water treatment method according to one aspect of the present invention, in the above invention, the first water extraction step includes a low pressure reverse osmosis step of extracting the permeated water by a low pressure reverse osmosis membrane, and the second water extraction step. However, it is characterized by including a high-pressure reverse osmosis step of extracting the permeated water by a high-pressure reverse osmosis membrane or a normal permeation step of extracting the permeated water by the normal osmosis membrane.
　本発明の一態様に係る水処理方法は、上記の発明において、前記第２水抽出工程の後に、前記高濃縮水に対して蒸留処理および晶析処理の少なくとも一方を行って精製水を排出する蒸留晶析工程を含むことを特徴とする。 In the water treatment method according to one aspect of the present invention, in the above invention, after the second water extraction step, at least one of distillation treatment and crystallization treatment is performed on the highly concentrated water to discharge purified water. It is characterized by including a distillation crystallization step.
　本発明の一態様に係る水処理方法は、上記の発明において、前記不純物がカルシウムを含み、前記第１凝集沈殿工程の後かつ前記第１水抽出工程の前と、前記第２凝集沈殿工程の後かつ前記第２水抽出工程の前との少なくとも一方において、前記カルシウムを除去するカルシウム除去工程を含むことを特徴とする。 According to the water treatment method according to one aspect of the present invention, in the above invention, the impurities contain calcium, and after the first coagulation-precipitation step and before the first water extraction step, and in the second coagulation-precipitation step. It is characterized by including a calcium removing step of removing the calcium after and at least one of before and after the second water extraction step.
　本発明の一態様に係る水処理方法は、上記の発明において、前記不純物がカルシウムを含み、前記第１水抽出工程の前に、前記被処理水にカルシウム分散剤を添加するカルシウム分散工程を含むことを特徴とする。 In the above invention, the water treatment method according to one aspect of the present invention includes a calcium dispersion step in which the impurity contains calcium and a calcium dispersant is added to the water to be treated before the first water extraction step. It is characterized by that.
　本発明の一態様に係る水処理方法は、上記の発明において、前記第１凝集沈殿工程および前記第２凝集沈殿工程において前記シリカを凝集させる凝集剤が、ポリ塩化アルミニウムまたは塩化アルミニウムと、前記被処理水にポリ塩化アルミニウムまたは塩化アルミニウムが添加されて前記第１凝集沈殿工程および前記第２凝集沈殿工程の少なくとも一方において凝集沈殿された凝集沈殿汚泥と、を含むことを特徴とする。 In the water treatment method according to one aspect of the present invention, in the above invention, the flocculant that aggregates the silica in the first coagulation-precipitation step and the second coagulation-precipitation step is polyaluminum chloride or aluminum chloride, and the subject. It is characterized by containing a coagulated sedimentation sludge in which polyaluminum chloride or aluminum chloride is added to the treated water and coagulated and precipitated in at least one of the first coagulation sedimentation step and the second coagulation sedimentation step.
　本発明の一態様に係る水処理方法は、上記の発明において、前記不純物がマグネシウムを含むことを特徴とする。 The water treatment method according to one aspect of the present invention is characterized in that, in the above invention, the impurity contains magnesium.
　本発明に係る水処理装置および水処理方法によれば、不純物を含む被処理水から水を抽出する場合に、スケールの発生を抑制しつつ水の回収率を向上することが可能になる。 According to the water treatment apparatus and the water treatment method according to the present invention, when water is extracted from the water to be treated containing impurities, it is possible to improve the water recovery rate while suppressing the generation of scale.
図１は、本発明の第１の実施形態による水処理装置を模式的に示すブロック図である。FIG. 1 is a block diagram schematically showing a water treatment apparatus according to the first embodiment of the present invention. 図２は、本発明の第１の実施形態の第１変形例による水処理装置を模式的に示すブロック図である。FIG. 2 is a block diagram schematically showing a water treatment apparatus according to a first modification of the first embodiment of the present invention. 図３は、比較例としての従来技術による水処理装置を模式的に示すブロック図である。FIG. 3 is a block diagram schematically showing a water treatment apparatus according to a prior art as a comparative example. 図４は、本発明の第２の実施形態による水処理装置を模式的に示すブロック図である。FIG. 4 is a block diagram schematically showing a water treatment apparatus according to a second embodiment of the present invention. 図５は、本発明の第２の実施形態の第２変形例による水処理装置を模式的に示すブロック図である。FIG. 5 is a block diagram schematically showing a water treatment apparatus according to a second modification of the second embodiment of the present invention. 図６は、本発明の第３の実施形態による水処理装置を模式的に示すブロック図である。FIG. 6 is a block diagram schematically showing a water treatment apparatus according to a third embodiment of the present invention. 図７は、本発明の第３の実施形態の第３変形例による水処理装置を模式的に示すブロック図である。FIG. 7 is a block diagram schematically showing a water treatment apparatus according to a third modification of the third embodiment of the present invention. 図８は、本発明の第４の実施形態による水処理装置を模式的に示すブロック図である。FIG. 8 is a block diagram schematically showing a water treatment apparatus according to a fourth embodiment of the present invention. 図９は、本発明の第４の実施形態の第４変形例による水処理装置を模式的に示すブロック図である。FIG. 9 is a block diagram schematically showing a water treatment apparatus according to a fourth modification of the fourth embodiment of the present invention. 図１０は、本発明の実施形態による凝集沈殿部およびろ過部の第１構成例を模式的に示すブロック図である。FIG. 10 is a block diagram schematically showing a first configuration example of a coagulation sedimentation portion and a filtration portion according to an embodiment of the present invention. 図１１は、本発明の実施形態による凝集沈殿部およびろ過部の第２構成例を模式的に示すブロック図である。FIG. 11 is a block diagram schematically showing a second configuration example of the coagulation sedimentation portion and the filtration portion according to the embodiment of the present invention. 図１２は、本発明の実施形態による凝集沈殿部およびろ過部の第３構成例を模式的に示すブロック図である。FIG. 12 is a block diagram schematically showing a third configuration example of the coagulation sedimentation portion and the filtration portion according to the embodiment of the present invention. 図１３は、本発明の実施形態による凝集沈殿部およびろ過部の第４構成例を模式的に示すブロック図である。FIG. 13 is a block diagram schematically showing a fourth configuration example of the coagulation sedimentation portion and the filtration portion according to the embodiment of the present invention. 図１４は、本発明の実施形態による正浸透装置の第１装置例を模式的に示すブロック図である。FIG. 14 is a block diagram schematically showing an example of a first device of a forward osmosis device according to an embodiment of the present invention. 図１５は、本発明の実施形態による正浸透装置の第２装置例を模式的に示すブロック図である。FIG. 15 is a block diagram schematically showing an example of a second device of the forward osmosis device according to the embodiment of the present invention. 図１６は、本発明の実施形態による正浸透装置の第３装置例を模式的に示すブロック図である。FIG. 16 is a block diagram schematically showing an example of a third device of the forward osmosis device according to the embodiment of the present invention. 図１７は、本発明の実施形態による正浸透装置の第４装置例を模式的に示すブロック図である。FIG. 17 is a block diagram schematically showing an example of a fourth device of the forward osmosis device according to the embodiment of the present invention.
　以下、本発明の実施形態について図面を参照しつつ説明する。なお、以下の実施形態の全図においては、同一または対応する部分には同一の符号を付す。また、本発明は以下に説明する実施形態によって限定されるものではない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings of the following embodiments, the same or corresponding parts are designated by the same reference numerals. Further, the present invention is not limited to the embodiments described below.
　本発明は、被処理水としてブローダウン水、海水、河川水、工業排水などの含水溶液を処理して淡水を得る水処理において、カルシウム塩やシリカなどに起因するスケーリングを抑制しつつ、淡水の回収率を向上する技術に関する。 According to the present invention, in water treatment for obtaining fresh water by treating an aqueous solution such as blowdown water, seawater, river water, and industrial wastewater as water to be treated, fresh water is suppressed while suppressing scaling caused by calcium salts, silica, and the like. The present invention relates to a technique for improving the recovery rate.
　まず、本発明の理解を容易にするために、本発明者が行った鋭意検討について以下に説明する。上述したように、逆浸透（ＲＯ：Reverse　Osmosis）膜などの膜を用いて水処理を行う過程における濃縮に伴って膜の内部で溶解度を超えてしまうと、スケーリングが生じ、膜の閉塞の原因になる。スケーリングが発生すると、膜の水透過性の低下や原水の供給側における圧力損失の上昇を引き起こし、水処理装置の運転の継続が困難になる。 First, in order to facilitate the understanding of the present invention, the diligent studies conducted by the present inventor will be described below. As described above, if the solubility is exceeded inside the membrane due to concentration in the process of water treatment using a membrane such as a reverse osmosis (RO) membrane, scaling occurs, which causes blockage of the membrane. become. When scaling occurs, the water permeability of the membrane decreases and the pressure loss on the raw water supply side increases, making it difficult to continue the operation of the water treatment apparatus.
　スケーリングを発生させる塩類は溶解度の低い成分である。具体的に、スケーリングを発生させる原因物質は、主として難溶性の塩であって、例えば、シリカ（ＳｉＯ2、二酸化ケイ素）、炭酸カルシウム（ＣａＣＯ3）、硫酸カルシウム（ＣａＳＯ4）、水酸化マグネシウム（Ｍｇ（ＯＨ）2）、硫酸バリウム（ＢａＳＯ4）、およびフッ化カルシウム（ＣａＦ2）などが挙げられる。以下に、ＣａＳＯ4およびシリカを例にスケーリングの抑制について説明する。 Salts that cause scaling are components with low solubility. Specifically, the causative substances that cause scaling are mainly sparingly soluble salts, such as silica (SiO 2 , silicon dioxide), calcium carbonate (CaCO 3 ), calcium sulfate (CaSO 4 ), and magnesium hydroxide (CaSO 4). Mg (OH) 2 ), barium sulfate (BaSO 4 ), calcium fluoride (CaF 2 ) and the like can be mentioned. Scaling suppression will be described below using CaSO 4 and silica as examples.
　まず、ＣａＳＯ4は難溶性の塩であって、酸やアルカリに溶解しないことから、一度析出すると除去が困難である。そこで、膜を用いて濃縮する被処理水にＣａＳＯ4が含まれている場合、ＣａＳＯ4を析出させない方法として、膜の前段に凝集沈殿部を設けたりカチオン交換樹脂を用いた軟水器を設置したりすることによって、カルシウム（Ｃａ）を除去する方法や、膜の前段においてスケール分散剤などの薬剤を添加してＣａＳＯ4の生成を抑制する方法などが知られている。 First, CaSO 4 is a sparingly soluble salt and does not dissolve in acids or alkalis, so it is difficult to remove it once it is precipitated. Therefore, when CaSO 4 is contained in the water to be treated that is concentrated using a membrane, as a method of preventing CaSO 4 from precipitating, a coagulation sedimentation portion is provided in front of the membrane or a water softener using a cation exchange resin is installed. There are known methods such as removing calcium (Ca) and suppressing the production of CaSO 4 by adding a drug such as a scale dispersant in the pre-stage of the membrane.
　本発明者は種々検討を行い、シリカも難溶性の塩であることから、膜の前段に凝集沈殿部を設けてシリカを除去する方法を案出した。なお、本明細書において、シリカとは、二酸化ケイ素、またはＳｉＯ2によって構成される物質の総称である。ここで、シリカはアルカリ性においては溶解度が大幅に上昇する。そのため、水酸化ナトリウム（ＮａＯＨ）などのｐＨ調整剤を凝集沈殿部に添加して、被処理水をアルカリ性にすることによって、シリカからなるスケールの発生を抑制できるが、膜がアルカリに対して耐性を有する必要がある。また、シリカは酸性において溶解度の変化が微小であるものの、結晶化の速度が低下するため、ｐＨ調整剤として塩酸（ＨＣｌ）や硫酸（Ｈ2ＳＯ4）などの酸を添加することによって、シリカからなるスケールの発生を抑制できる場合がある。また、シリカを除去するために、ＣａＳＯ4の場合と同様に、膜の前段にスケール分散剤などの薬剤を添加する場合もある。 The present inventor has conducted various studies and devised a method for removing silica by providing a coagulation-precipitating portion in front of the film because silica is also a poorly soluble salt. In the present specification, silica is a general term for substances composed of silicon dioxide or SiO 2 . Here, the solubility of silica is significantly increased in alkalinity. Therefore, by adding a pH adjuster such as sodium hydroxide (NaOH) to the coagulated precipitate to make the water to be treated alkaline, the generation of scale composed of silica can be suppressed, but the film is resistant to alkali. Must have. In addition, although the change in solubility of silica is small in acidity, the rate of crystallization decreases. Therefore, by adding an acid such as hydrochloric acid (HCl) or sulfuric acid (H 2 SO 4 ) as a pH adjuster, silica It may be possible to suppress the generation of scale consisting of. Further, in order to remove silica, a chemical such as a scale dispersant may be added to the front stage of the membrane as in the case of CaSO 4 .
　また、本発明者はさらに検討を進め、ＲＯ膜などによる膜を用いて得られた濃縮水に対してさらに凝集沈殿処理を行うことにより、Ｃａやシリカを除去した上で、正浸透装置や高圧逆浸透膜などによって濃縮水をさらに濃縮させる方法を案出した。以下に説明する実施形態は、以上の本発明者の鋭意検討に基づいて、案出されたものである。 In addition, the present inventor further studies, and after removing Ca and silica by further coagulating and precipitating the concentrated water obtained by using a membrane such as an RO membrane, a forward osmosis device or a high pressure is used. We devised a method to further concentrate the concentrated water with a reverse osmosis membrane or the like. The embodiments described below have been devised based on the above-mentioned diligent studies of the present inventor.
　（第１の実施形態）
　（水処理装置）
　まず、本発明の第１の実施形態による水処理装置について説明する。以下に説明する第１の実施形態による水処理装置１は、例えば、冷却塔などから排出されたブローダウン水を被処理水として、再利用可能な再生水および廃棄物となる高濃縮塩水または固体の塩を得る装置である。図１は、第１の実施形態による水処理装置１を模式的に示すブロック図である。図１に示すように、第１の実施形態による水処理装置１は、第１凝集沈殿部１０、第１ろ過部２０、軟水器３０、低圧逆浸透部４０、第２凝集沈殿部５０、第２ろ過部６０、正浸透装置７０、および蒸留晶析部８０を備えて構成される。 (First Embodiment)
(Water treatment equipment)
First, the water treatment apparatus according to the first embodiment of the present invention will be described. In the water treatment apparatus 1 according to the first embodiment described below, for example, the blowdown water discharged from a cooling tower or the like is used as the water to be treated, and the reclaimed reclaimed water and the highly concentrated salt water or solid as waste are used. It is a device for obtaining salt. FIG. 1 is a block diagram schematically showing the water treatment apparatus 1 according to the first embodiment. As shown in FIG. 1, the water treatment apparatus 1 according to the first embodiment includes a first coagulation sedimentation section 10, a first filtration section 20, a water softener 30, a low pressure reverse osmosis section 40, a second coagulation sedimentation section 50, and a second coagulation sedimentation section. 2 The filtration unit 60, the normal osmosis device 70, and the distillation crystallization unit 80 are provided.
　複数の凝集沈殿部の一部としての第１凝集沈殿部１０は、シリカやカルシウムなどのスケール成分を含む被処理水に対して凝集剤を添加することにより、スケール成分をスラッジとして凝集沈殿させる処理部である。第１凝集沈殿部１０においては、スケール成分として、ＣａＣＯ3およびシリカを除去する。第１凝集沈殿部１０には、例えばＮａＯＨまたは水酸化カルシウム（Ｃａ(ＯＨ)2）などのアルカリと、炭酸ナトリウム（Ｎａ2ＣＯ3）と、ポリ塩化アルミニウム（ＰＡＣ：ＡｌＣｌ3）とを添加する。なお、ポリ塩化アルミニウムの代わりに、塩化アルミニウム（ＡｌＣｌ3）を用いても良い。 The first coagulation-precipitating portion 10 as a part of the plurality of coagulation-precipitating portions is a treatment for coagulating and precipitating the scale component as sludge by adding a coagulant to the water to be treated containing the scale component such as silica and calcium. It is a department. In the first coagulation sedimentation section 10, CaCO 3 and silica are removed as scale components. To the first coagulation-precipitated portion 10, for example, an alkali such as NaOH or calcium hydroxide (Ca (OH) 2 ), sodium carbonate (Na 2 CO 3 ), and polyaluminum chloride (PAC: AlCl 3 ) are added. .. In addition, aluminum chloride (AlCl 3 ) may be used instead of polyaluminum chloride.
　ここで、第１凝集沈殿部１０において、凝集沈殿を生じさせる反応槽（図１中、図示せず）のｐＨは、８以上１２以下の例えば１０．５に調整することが好ましい。また、Ｎａ2ＣＯ3の濃度はＣａに対して当量とし、ＰＡＣの濃度はＳｉＯ2に対して２倍当量とすることが好ましいが、必ずしも限定されない。 Here, in the first coagulation-precipitation section 10, the pH of the reaction vessel (not shown in FIG. 1) that causes coagulation-precipitation is preferably adjusted to 8 or more and 12 or less, for example, 10.5. Further, it is preferable that the concentration of Na 2 CO 3 is equivalent to Ca and the concentration of PAC is twice equivalent to SiO 2 , but it is not always limited.
　第１凝集沈殿部１０において例えば３０分間以上静置された被処理水は、ｐＨが４以上８以下の例えば６．５程度に調整された後、第１ろ過部２０に供給される。被処理水のｐＨが６．５程度に調整されることにより、被処理水に含まれるＰＡＣに起因するアルミニウム（Ａｌ）が不溶性になる。 The water to be treated, which has been allowed to stand in the first coagulation sedimentation section 10 for, for example, 30 minutes or more, is supplied to the first filtration section 20 after the pH is adjusted to 4 or more and 8 or less, for example, about 6.5. By adjusting the pH of the water to be treated to about 6.5, the aluminum (Al) caused by PAC contained in the water to be treated becomes insoluble.
　複数のろ過部の一部としての第１ろ過部２０は、例えば砂ろ過器などから構成される。第１ろ過部２０は、精密ろ過膜（ＭＦ膜）や限外ろ過膜（ＵＦ膜）などの所定の膜を用いた膜ろ過装置から構成しても良い。第１ろ過部２０においては、供給されたＰＡＣを含む被処理水が例えば３０分間以上静置される。これにより、第１ろ過部２０において、未反応のＰＡＣが除去される。ＰＡＣが除去された被処理水は、軟水器３０に供給される。上述した第１凝集沈殿部１０およびろ過部２０の詳細については、後述する。 The first filtration unit 20 as a part of the plurality of filtration units is composed of, for example, a sand filter or the like. The first filtration unit 20 may be composed of a membrane filtration device using a predetermined membrane such as a microfiltration membrane (MF membrane) or an ultrafiltration membrane (UF membrane). In the first filtration unit 20, the supplied water to be treated containing PAC is allowed to stand for, for example, 30 minutes or more. As a result, the unreacted PAC is removed in the first filtration unit 20. The water to be treated from which the PAC has been removed is supplied to the water softener 30. Details of the first coagulation sedimentation section 10 and the filtration section 20 described above will be described later.
　カルシウム除去部としての軟水器３０は、被処理水に含まれるＣａイオンやマグネシウム（Ｍｇ）イオンなどの陽イオンを、陽イオン交換樹脂（カチオン交換樹脂）によって、ナトリウム（Ｎａ）イオンに置換する装置である。被処理水において、ＨＣＯ3やＳＯ4などの濃度が高い状態であって、Ｃａを含むスケール成分のスケールリスクが高い場合、第１凝集沈殿部１０による凝集沈殿で低減されたＣａ濃度では不十分な場合がある。このような場合に、軟水器３０を用いてＣａを除去することが好ましい。 The water softener 30 as a calcium removing unit is a device that replaces cations such as Ca ions and magnesium (Mg) ions contained in the water to be treated with sodium (Na) ions by a cation exchange resin (cation exchange resin). Is. When the concentration of HCO 3 or SO 4 is high in the water to be treated and the scale risk of the scale component containing Ca is high, the Ca concentration reduced by the coagulation sedimentation by the first coagulation sedimentation portion 10 is insufficient. In some cases. In such a case, it is preferable to remove Ca using a water softener 30.
　第１の実施形態において軟水器３０は、低圧逆浸透部４０の前段に設けられているが、必ずしも限定されない。軟水器３０は、第１凝集沈殿部１０や第２凝集沈殿部５０と、スケーリングが発生しやすい装置との間に設けることが好ましい。また、軟水器３０を設けることによって、Ｍｇを除去できるので、後段に設けられた低圧逆浸透部４０などをアルカリ性の条件下で運転する場合に、Ｍｇ（ＯＨ）2のスケールリスクを効率良く低減することができる。 In the first embodiment, the water softener 30 is provided in front of the low pressure reverse osmosis unit 40, but is not necessarily limited. The water softener 30 is preferably provided between the first coagulation sedimentation portion 10 or the second coagulation sedimentation portion 50 and an apparatus in which scaling is likely to occur. Further, since Mg can be removed by providing the water softener 30, the scale risk of Mg (OH) 2 is efficiently reduced when the low-pressure reverse osmosis portion 40 or the like provided in the subsequent stage is operated under alkaline conditions. can do.
　ここで、軟水器３０の再生には、塩化ナトリウム（ＮａＣｌ）水溶液が用いられる。また、ゼロ排水プロセス（ＺＬＤ）の場合、再生廃液は、蒸留晶析部８０において処理できる。また、ＲＯ膜をアルカリ性の条件下で使用する場合、Ｍｇ(ＯＨ)2のスケールリスクが高いが、軟水器３０によってＭｇを除去できるので、低圧逆浸透膜や高圧逆浸透膜におけるスケールリスクを低減できる。さらに、軟水器３０から微量のＣａがリークして、ＣａＣＯ3からなるスケールが生じる可能性がある場合には、軟水器３０の後段に脱炭酸塔や脱炭酸膜（いずれも図示せず）を設置することによって、ＣａＣＯ3からなるスケールの発生を抑制することが好ましい。 Here, an aqueous solution of sodium chloride (NaCl) is used for the regeneration of the water softener 30. Further, in the case of the zero wastewater process (ZLD), the regenerated waste liquid can be treated in the distillation crystallization unit 80. Further, when the RO membrane is used under alkaline conditions, the scale risk of Mg (OH) 2 is high, but since Mg can be removed by the water softener 30, the scale risk in the low pressure reverse osmosis membrane and the high pressure reverse osmosis membrane is reduced. can. Furthermore, if there is a possibility that a small amount of Ca leaks from the water softener 30 and a scale consisting of CaCO 3 is generated, a decarbonation tower or a decarbonation film (neither is shown) is installed after the water softener 30. By installing it, it is preferable to suppress the generation of scale consisting of CaCO 3 .
　複数の水抽出部の一部または第１水抽出部としての低圧逆浸透部４０は、低圧逆浸透膜（低圧ＲＯ膜）を有して構成される。低圧ＲＯ膜としては、例えば商品名が「ＥＳＰＡ２－ＬＤ」、「ＥＳＰＡ２　ＭＡＸ」、または「ＥＳＰＡ１」（いずれもHydranautics社製）や、商品名が「ＴＭＧ２０－４００」、「ＴＭＧ２０－４４０Ｃ」、または「ＴＬＦ－４００ＤＧ」（いずれも東レ社製）などが用いられる。低圧逆浸透部４０は、例えば４ＭＰａ程度の低圧力を作用させた逆浸透によって被処理水から不純物濃度が低下された透過水を得るとともに、不純物が濃縮された濃縮水を排出する。得られた透過水は再生水として回収される。一方、排出された濃縮水は第２凝集沈殿部５０に供給される。 The low-pressure reverse osmosis section 40 as a part of the plurality of water extraction sections or the first water extraction section is configured to have a low-pressure reverse osmosis membrane (low-pressure RO membrane). Examples of the low-pressure RO membrane include the product names "ESPA2-LD", "ESPA2 MAX", or "ESPA1" (all manufactured by Hydranautics), and the product names "TMG20-400", "TMG20-440C", or "TLF-400DG" (both manufactured by Toray Industries, Inc.) and the like are used. The low-pressure reverse osmosis unit 40 obtains permeated water having a reduced impurity concentration from the water to be treated by reverse osmosis in which a low pressure of, for example, about 4 MPa is applied, and discharges concentrated water in which impurities are concentrated. The obtained permeated water is recovered as reclaimed water. On the other hand, the discharged concentrated water is supplied to the second coagulation sedimentation section 50.
　複数の凝集沈殿部の他部としての第２凝集沈殿部５０は、被処理水である濃縮水に含まれるスケール成分をスラッジとして凝集沈殿させる点については、第１凝集沈殿部１０と同様である。第２凝集沈殿部５０においては、スケール成分としてＳｉＯ2を除去する。そのため、第１凝集沈殿部１０と異なり、第２凝集沈殿部５０の被処理水としての濃縮水には、凝集剤としてＰＡＣが添加される。これにより、濃縮水に含まれるＳｉＯ2がスラッジとして凝集沈殿されて、除去される。 The second coagulation sedimentation section 50 as another part of the plurality of coagulation sedimentation sections is the same as the first coagulation sedimentation section 10 in that the scale component contained in the concentrated water to be treated is coagulated and precipitated as sludge. .. In the second coagulation sedimentation section 50, SiO 2 is removed as a scale component. Therefore, unlike the first coagulation sedimentation section 10, PAC is added as a coagulation agent to the concentrated water as the water to be treated of the second coagulation sedimentation section 50. As a result, SiO 2 contained in the concentrated water is coagulated and precipitated as sludge and removed.
　第２凝集沈殿部５０において例えば３０分間以上静置された濃縮水は、ｐＨが４以上８以下の例えば６．５程度に調整された後、第２ろ過部６０に供給される。濃縮水のｐＨが６．５程度に調整されることにより、濃縮水に含まれるＰＡＣに起因するＡｌが不溶性になる。なお、濃縮水のｐＨを５程度に調整することも可能である。 The concentrated water that has been allowed to stand in the second coagulation sedimentation section 50 for, for example, 30 minutes or more is supplied to the second filtration section 60 after the pH is adjusted to 4 or more and 8 or less, for example, about 6.5. By adjusting the pH of the concentrated water to about 6.5, Al caused by PAC contained in the concentrated water becomes insoluble. It is also possible to adjust the pH of the concentrated water to about 5.
　複数のろ過部の他部としての第２ろ過部６０は、第１ろ過部２０と同様に構成される。第２ろ過部６０においては、供給された濃縮水を例えば３０分間以上静置させることによって、未反応のＰＡＣが除去される。ＰＡＣが除去された濃縮水は、第２ろ過部６０から正浸透装置７０に供給される。 The second filtration unit 60 as another unit of the plurality of filtration units is configured in the same manner as the first filtration unit 20. In the second filtration unit 60, unreacted PAC is removed by allowing the supplied concentrated water to stand for, for example, 30 minutes or more. The concentrated water from which the PAC has been removed is supplied from the second filtration unit 60 to the forward osmosis device 70.
　複数の水抽出部の他部または正浸透部としての正浸透装置７０においては、例えば温度感応性吸水剤を用いた正浸透処理が実行され、濃縮水から透過水が得られるとともに、濃縮水がさらに濃縮されて高濃度濃縮水（以下、高濃縮水）とされる。換言すると、高濃縮水は濃縮水に対する濃縮水である。得られた透過水は再生水として、低圧逆浸透部４０から排出される透過水に合流される。一方、高濃縮水は、蒸留晶析部８０に供給される。 In the forward osmosis device 70 as the other part or the forward osmosis part of the plurality of water extraction units, for example, a forward osmosis treatment using a temperature-sensitive water absorbing agent is executed to obtain permeated water from the concentrated water, and the concentrated water is produced. It is further concentrated to obtain highly concentrated water (hereinafter referred to as highly concentrated water). In other words, highly concentrated water is concentrated water as opposed to concentrated water. The obtained permeated water is merged with the permeated water discharged from the low-pressure reverse osmosis unit 40 as reclaimed water. On the other hand, the highly concentrated water is supplied to the distillation crystallization unit 80.
　なお、正浸透装置７０に設けられる正浸透（ＦＯ：Forward　Osmosis）膜（図１中、図示せず）の材質が酢酸セルロースの場合、酢酸セルロースはアルカリに弱く、シリカの溶解度を上げることができるアルカリ性の条件下では、正浸透装置７０の運転が困難になる。そのため、上述したように、正浸透装置７０の前段の第２凝集沈殿部５０によってシリカを除去することにより、正浸透装置７０における被処理水を中性に調整できるので、酢酸セルロースからなるＦＯ膜を用いた運転を維持できる。さらに、シリカのスケールを抑制するためには、正浸透装置７０における原水側の出口のｐＨを５．５程度になるように調整することが望ましい。 When the material of the forward osmosis (FO: Forward Osmosis) film (not shown in FIG. 1) provided in the forward osmosis apparatus 70 is cellulose acetate, cellulose acetate is vulnerable to alkali and can increase the solubility of silica. Under alkaline conditions, the forward osmosis device 70 becomes difficult to operate. Therefore, as described above, the water to be treated in the forward osmosis apparatus 70 can be adjusted to neutral by removing silica by the second coagulation sedimentation portion 50 in the previous stage of the forward osmosis apparatus 70, so that the FO film made of cellulose acetate can be adjusted. It is possible to maintain the operation using. Further, in order to suppress the scale of silica, it is desirable to adjust the pH of the outlet on the raw water side of the forward osmosis device 70 to be about 5.5.
　蒸留晶析部８０においては、所定のエネルギー、具体的にはスチーム（蒸気）や、電力を供給することによって、高濃縮水に対して、蒸留処理および晶析処理の少なくとも一方、すなわち、従来公知の、蒸留処理および晶析処理、蒸留処理、または晶析処理などの精製処理を行う。蒸留晶析部８０において精製された精製水は、低圧逆浸透部４０から排出される透過水に合流されて再生水として回収される。精製水から分離された固形成分としての塩は、外部に廃棄される。これにより、固形分以外の廃棄物を極力発生させないゼロ排水プロセス（ＺＬＤ）を達成することができる。 In the distillation crystallization unit 80, at least one of distillation treatment and crystallization treatment, that is, conventionally known, is applied to highly concentrated water by supplying predetermined energy, specifically steam (steam) or electric power. Is subjected to purification treatment such as distillation treatment and crystallization treatment, distillation treatment, or crystallization treatment. The purified water purified in the distillation crystallization unit 80 is merged with the permeated water discharged from the low-pressure reverse osmosis unit 40 and recovered as reclaimed water. The salt as a solid component separated from purified water is discarded to the outside. This makes it possible to achieve a zero drainage process (ZLD) that produces as little waste as possible other than solids.
　（第１実施例）
　（水処理方法）
　次に、以上のように構成された第１の実施形態による水処理装置１を用いた水処理方法の第１実施例について説明する。なお、第１実施例においては、冷却塔などから排出されたブローダウン水を被処理水とし、単位時間当たり、１０００Ｌ（１０００Ｌ／ｈ）の被処理水から９９６Ｌ（９９６Ｌ／ｈ）の再生水を得るとともに、４Ｌ（４Ｌ／ｈ）分に相当する塩を排出する場合を例に説明する。 (First Example)
(Water treatment method)
Next, a first embodiment of the water treatment method using the water treatment apparatus 1 according to the first embodiment configured as described above will be described. In the first embodiment, the blowdown water discharged from the cooling tower or the like is used as the water to be treated, and 996 L (996 L / h) of reclaimed water is obtained from 1000 L (1000 L / h) of the water to be treated per unit time. In addition, a case where salt corresponding to 4 L (4 L / h) is discharged will be described as an example.
　まず、水処理装置１に導入される被処理水の流量および各成分は以下のようになる。
　流量：１０００Ｌ／ｈ、ＴＤＳ（総溶解固形分：Total　Dissolved　Solids）：４０２２ｍｇ／Ｌ、Ｃａ：２６６ｍｇ／Ｌ、ＳｉＯ2：１２６ｍｇ／Ｌ First, the flow rate of the water to be treated and each component introduced into the water treatment apparatus 1 are as follows.
Flow rate: 1000 L / h, TDS (Total Dissolved Solids): 4022 mg / L, Ca: 266 mg / L, SiO 2 : 126 mg / L
　（第１凝集沈殿工程）
　被処理水が水処理装置１に導入されると第１凝集沈殿部１０に供給されて、第１凝集沈殿工程が行われる。第１凝集沈殿部１０の被処理水に添加されるｐＨ調整剤は、例えばＮａＯＨおよびＣａ（ＯＨ）2の少なくとも一方、すなわちアルカリである。なお、アルカリとしては、これらに限定されない。これにより、被処理水のｐＨは１０．５程度に調整される。 (First coagulation sedimentation step)
When the water to be treated is introduced into the water treatment apparatus 1, it is supplied to the first coagulation sedimentation section 10 to perform the first coagulation sedimentation step. The pH adjuster added to the water to be treated in the first coagulation sedimentation section 10 is, for example, at least one of NaOH and Ca (OH) 2 , that is, an alkali. The alkali is not limited to these. Thereby, the pH of the water to be treated is adjusted to about 10.5.
　第１凝集沈殿部１０の被処理水に添加される凝集剤は、例えばＮａ2ＣＯ3およびＰＡＣである。ここで添加するＮａ2ＣＯ3はＣａに対して当量、ＰＡＣはＳｉＯ2に対して２倍当量加えることが好ましいが限定されない。第１凝集沈殿部１０においては、この状態で３０分程度静置される。第１凝集沈殿部１０においては、被処理水からスケール成分として、ＣａＣＯ3およびシリカの少なくとも一部が凝集されて除去される。第１凝集沈殿部１０から排出される被処理水の各成分は以下のようになる。
　ＴＤＳ：４００５ｍｇ／Ｌ、Ｃａ：５０ｍｇ／Ｌ、ＳｉＯ2：１０ｍｇ／Ｌ
　すなわち、第１凝集沈殿部１０において、Ｃａが（２６６－５０＝）２１６ｍｇ／Ｌ、ＳｉＯ2が（１２６－１０＝）１１６ｍｇ／Ｌだけ、除去される。 The flocculants added to the water to be treated in the first coagulation sedimentation section 10 are, for example, Na 2 CO 3 and PAC. It is preferable, but not limited to, that Na 2 CO 3 added here is equivalent to Ca and PAC is added twice equivalent to SiO 2 . The first coagulation-precipitating portion 10 is allowed to stand in this state for about 30 minutes. In the first coagulation sedimentation section 10, at least a part of CaCO 3 and silica are aggregated and removed from the water to be treated as scale components. Each component of the water to be treated discharged from the first coagulation sedimentation portion 10 is as follows.
TDS: 4005 mg / L, Ca: 50 mg / L, SiO 2 : 10 mg / L
That is, in the first coagulation sedimentation section 10, Ca is removed by (266-50 =) 216 mg / L and SiO 2 is removed by (126-10 =) 116 mg / L.
　（第１ろ過工程）
　第１凝集沈殿部１０においてスケール成分が凝集沈殿されて得られた上澄み水は、被処理水として第１ろ過部２０に供給されて、第１ろ過工程が行われる。第１ろ過部２０においては、硫酸（Ｈ2ＳＯ4）またはＨＣｌなどの酸を添加することにより、ｐＨが６．５程度に調整される。第１ろ過部２０においては、被処理水が３０分間以上静置されて、未反応のＰＡＣが除去される。 (1st filtration step)
The supernatant water obtained by coagulating and precipitating the scale component in the first coagulation sedimentation section 10 is supplied to the first filtration section 20 as water to be treated, and the first filtration step is performed. In the first filtration unit 20, the pH is adjusted to about 6.5 by adding an acid such as sulfuric acid (H 2 SO 4 ) or HCl. In the first filtration unit 20, the water to be treated is allowed to stand for 30 minutes or more to remove unreacted PAC.
　（カルシウム除去工程）
　第１ろ過部２０においてＰＡＣが除去された被処理水は、軟水器３０に供給されてカルシウム除去工程が行われる。軟水器３０においては、例えば、カチオン交換樹脂などによって被処理水からＣａが除去される。なお、カルシウム除去工程は、第１凝集沈殿工程や後述する第２凝集沈殿工程の後であって、カルシウム塩などのスケーリングが発生しやすい工程の前に行うことが好ましい。軟水器３０から排出される被処理水の各成分は以下のようになる。
　ＴＤＳ：４０３０ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：１０ｍｇ／Ｌ
　すなわち、軟水器３０において、Ｃａが略（５０－０＝）５０ｍｇ／Ｌ（全量）除去される。 (Calcium removal process)
The water to be treated from which the PAC has been removed by the first filtration unit 20 is supplied to the water softener 30 to perform a calcium removal step. In the water softener 30, Ca is removed from the water to be treated by, for example, a cation exchange resin. The calcium removal step is preferably performed after the first coagulation-precipitation step and the second coagulation-precipitation step described later, and before the step in which scaling of the calcium salt or the like is likely to occur. Each component of the water to be treated discharged from the water softener 30 is as follows.
TDS: 4030 mg / L, Ca: 0 mg / L, SiO 2 : 10 mg / L
That is, in the water softener 30, Ca is substantially (50-0 =) 50 mg / L (total amount) removed.
　（低圧逆浸透工程）
　軟水器３０においてＣａが除去された被処理水は、低圧逆浸透部４０に供給されて水抽出工程または第１水抽出工程としての低圧逆浸透工程が行われる。低圧逆浸透部４０においては、ＴＤＳに依存する所定の圧力、ここでは例えば４．０ＭＰａの圧力を作用させたＲＯ膜によって被処理水から９０％の再生水を回収する一方、１０％の濃縮水が排出される。ここで、第１凝集沈殿部１０においてシリカが除去されていることにより、低圧逆浸透部４０による再生水の回収率を９０％まで向上させることができる。 (Low pressure reverse osmosis process)
The water to be treated from which Ca has been removed in the water softener 30 is supplied to the low-pressure reverse osmosis unit 40, and a low-pressure reverse osmosis step as a water extraction step or a first water extraction step is performed. In the low-pressure reverse osmosis section 40, 90% of the reclaimed water is recovered from the water to be treated by an RO membrane on which a predetermined pressure depending on TDS, for example, 4.0 MPa is applied, while 10% concentrated water is produced. It is discharged. Here, since silica is removed in the first coagulation-precipitation section 10, the recovery rate of reclaimed water by the low-pressure reverse osmosis section 40 can be improved to 90%.
　第１実施例においては、低圧逆浸透部４０から（１０００Ｌ／ｈ×９０％＝）９００Ｌ／ｈの流量で被処理水が排出されて再生水として回収される。再生水の各成分は以下のようになる。
　ＴＤＳ：４０ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：１ｍｇ／Ｌ
　すなわち、低圧逆浸透部４０において、ＴＤＳが（４０／４０３０≒）０．０１倍、ＳｉＯ2が（１／１０≒）０．１倍まで低減される。 In the first embodiment, the water to be treated is discharged from the low pressure reverse osmosis unit 40 at a flow rate of (1000 L / h × 90% =) 900 L / h and recovered as reclaimed water. Each component of reclaimed water is as follows.
TDS: 40 mg / L, Ca: 0 mg / L, SiO 2 : 1 mg / L
That is, in the low-pressure reverse osmosis section 40, TDS is reduced to (40/4030≈) 0.01 times and SiO 2 is reduced to (1/10≈) 0.1 times.
　また、低圧逆浸透部４０から（１０００Ｌ／ｈ×１０％＝）１００Ｌ／ｈの流量で濃縮水が排出される。濃縮水の各成分は以下のようになる。
　ＴＤＳ：３９９４０ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：９１ｍｇ／Ｌ
　すなわち、被処理水は低圧逆浸透部４０において、ＴＤＳが（３９９４０／４０３０≒）９．９倍、ＳｉＯ2が（９１／１０＝）９．１倍に濃縮される。 Further, concentrated water is discharged from the low-pressure reverse osmosis unit 40 at a flow rate of 100 L / h (1000 L / h × 10% =). Each component of concentrated water is as follows.
TDS: 39940 mg / L, Ca: 0 mg / L, SiO 2 : 91 mg / L
That is, in the low-pressure reverse osmosis section 40, TDS is concentrated (39940/4030≈) 9.9 times and SiO 2 is concentrated (91/10 =) 9.1 times in the water to be treated.
　（第２凝集沈殿工程）
　低圧逆浸透部４０において濃縮された濃縮水は、第２凝集沈殿部５０に供給されて第２凝集沈殿工程が行われる。なお、第１実施例においては、軟水器３０によって被処理水からＣａが除去されているため、第２凝集沈殿部５０の濃縮水に添加される凝集剤は、ＳｉＯ2を凝集させる例えばＰＡＣである。ここで添加するＰＡＣはＳｉＯ2に対して２倍当量加えることが好ましい。第１凝集沈殿部１０においては、この状態で３０分程度静置される。第１凝集沈殿部１０においては、被処理水からスケール成分として、シリカの少なくとも一部が凝集されて除去される。 (Second coagulation sedimentation step)
The concentrated water concentrated in the low-pressure reverse osmosis section 40 is supplied to the second coagulation sedimentation section 50 to perform the second coagulation sedimentation step. In the first embodiment, Ca is removed from the water to be treated by the water softener 30, so that the coagulant added to the concentrated water of the second coagulation sedimentation portion 50 is, for example, PAC that coagulates SiO 2 . be. The PAC added here is preferably added in an amount twice equivalent to SiO 2 . The first coagulation-precipitating portion 10 is allowed to stand in this state for about 30 minutes. In the first coagulation sedimentation section 10, at least a part of silica is aggregated and removed from the water to be treated as a scale component.
　（第２ろ過工程）
　第２凝集沈殿部５０においてスケール成分としてシリカが凝集沈殿されて得られた濃縮水は、第２ろ過部６０に供給されて、第２ろ過工程が行われる。第２ろ過部６０においては、Ｈ2ＳＯ4またはＨＣｌなどの酸を添加することにより、ｐＨが５～６．５程度に調整される。第２ろ過部６０においては、濃縮水が３０分間以上静置されて、未反応のＰＡＣが除去される。
　第２ろ過部６０から排出される濃縮水の各成分は以下のようになる。
　ＴＤＳ：４０３５０ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：１０ｍｇ／Ｌ
　すなわち、第２凝集沈殿部５０および第２ろ過部６０によって、ＳｉＯ2が（９１－１０＝）８１ｍｇ／Ｌ除去される。 (Second filtration step)
The concentrated water obtained by coagulating and precipitating silica as a scale component in the second coagulation sedimentation section 50 is supplied to the second filtration section 60 to perform the second filtration step. In the second filtration unit 60, the pH is adjusted to about 5 to 6.5 by adding an acid such as H 2 SO 4 or HCl. In the second filtration unit 60, the concentrated water is allowed to stand for 30 minutes or more to remove unreacted PAC.
Each component of the concentrated water discharged from the second filtration unit 60 is as follows.
TDS: 40350 mg / L, Ca: 0 mg / L, SiO 2 : 10 mg / L
That is, (91-10 =) 81 mg / L of SiO 2 is removed by the second coagulation sedimentation section 50 and the second filtration section 60.
　（正浸透処理工程）
　次に、第２ろ過部６０から排出された濃縮水は、正浸透装置７０に供給されて正浸透処理工程が行われる。正浸透装置７０においては、濃縮水から再生水が得られるとともにさらに濃縮された高濃縮水が排出される。具体的に、正浸透装置７０においては、ＦＯ膜によって濃縮水から（２／３≒）６７％の再生水を回収する一方、（１／３≒）３３％の高濃縮水が排出される。 (Forward osmosis treatment process)
Next, the concentrated water discharged from the second filtration unit 60 is supplied to the forward osmosis device 70 to perform a forward osmosis treatment step. In the forward osmosis device 70, reclaimed water is obtained from the concentrated water, and the highly concentrated water that is further concentrated is discharged. Specifically, in the forward osmosis apparatus 70, (2/3 ≈) 67% of reclaimed water is recovered from the concentrated water by the FO membrane, while (1/3 ≈) 33% of highly concentrated water is discharged.
　第１実施例においては、正浸透装置７０から（１００Ｌ／ｈ×６７％＝）６７Ｌ／ｈの流量で再生水として排出されて回収される。一方、正浸透装置７０から（１００Ｌ／ｈ×３３％＝）３３Ｌ／ｈの流量で高濃縮水が排出される。高濃縮水の各成分は以下のようになる。
　ＴＤＳ：１２１０５０ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：３０ｍｇ／Ｌ
　すなわち、濃縮水は、正浸透装置７０において、ＴＤＳが（１２１１０５０／４０３５０＝）３倍、ＳｉＯ2が（３０／１０＝）３倍に濃縮される。すなわち、第１実施例において、流量が１０００Ｌ／ｈの被処理水は、流量が３３Ｌ／ｈの高濃縮水として排出できることになる。一方、従来技術においては、流量が１０００Ｌ／ｈの被処理水に対して、排出される濃縮水の流量が２５０Ｌ／ｈである。すなわち、第１実施例による水処理装置１によれば、従来に比して被処理水をさらに７．６倍程度濃縮して排出でき、再生水の回収率を大幅に向上できる。 In the first embodiment, the reclaimed water is discharged and recovered from the forward osmosis device 70 at a flow rate of (100 L / h × 67% =) 67 L / h. On the other hand, highly concentrated water is discharged from the forward osmosis device 70 at a flow rate of (100 L / h × 33% =) 33 L / h. Each component of highly concentrated water is as follows.
TDS: 211050 mg / L, Ca: 0 mg / L, SiO 2 : 30 mg / L
That is, in the concentrated water, TDS is concentrated (1211050/40350 =) 3 times and SiO 2 is concentrated (30/10 =) 3 times in the forward osmosis apparatus 70. That is, in the first embodiment, the water to be treated having a flow rate of 1000 L / h can be discharged as highly concentrated water having a flow rate of 33 L / h. On the other hand, in the prior art, the flow rate of the concentrated water discharged is 250 L / h with respect to the water to be treated having a flow rate of 1000 L / h. That is, according to the water treatment apparatus 1 according to the first embodiment, the water to be treated can be further concentrated and discharged by about 7.6 times as compared with the conventional case, and the recovery rate of the reclaimed water can be significantly improved.
　（蒸留晶析工程）
　正浸透装置７０において濃縮された高濃縮水は、蒸留晶析部８０に供給されて蒸留晶析工程が行われる。蒸留晶析部８０においては、スチームや電力が供給されて、例えば１２０℃程度の温度で高濃縮水に対して、蒸留処理および晶析処理の少なくとも一方、すなわち、従来公知の、蒸留処理および晶析処理、蒸留処理、または晶析処理などの精製処理が行われる。なお、精製処理は、蒸留処理や晶析処理に限定されるものではなく、蒸発固化技術であれば種々の処理を採用できる。蒸留晶析部８０によって精製された精製水は再生水として回収される。精製水から分離された固形成分としての塩は、外部に廃棄される。第１実施例においては、流量が３３Ｌ／ｈの高濃縮水から、４Ｌ／ｈ分の固形成分が除去されて、流量が２９Ｌ／ｈの精製水が再生水として回収される。 (Distillation crystallization step)
The highly concentrated water concentrated in the forward osmosis apparatus 70 is supplied to the distillation crystallization unit 80 to perform the distillation crystallization step. In the distillation crystallization unit 80, steam or electric power is supplied, and at least one of distillation treatment and crystallization treatment, that is, conventionally known distillation treatment and crystallization treatment, is performed on highly concentrated water at a temperature of, for example, about 120 ° C. Purification treatments such as analysis treatment, distillation treatment, and crystallization treatment are performed. The purification treatment is not limited to the distillation treatment and the crystallization treatment, and various treatments can be adopted as long as it is an evaporation solidification technique. The purified water purified by the distillation crystallization unit 80 is recovered as reclaimed water. The salt as a solid component separated from purified water is discarded to the outside. In the first embodiment, 4 L / h of solid components are removed from the highly concentrated water having a flow rate of 33 L / h, and purified water having a flow rate of 29 L / h is recovered as reclaimed water.
　以上の低圧逆浸透部４０から得られる透過水に、正浸透装置７０から得られる透過水および蒸留晶析部８０から得られる精製水が供給されて回収される。これにより、第１の実施形態による水処理装置１によって、流量が１０００Ｌ／ｈの被処理水から、流量が（９００＋６７＋２９＝）９９６Ｌ／ｈの再生水が回収されるとともに、４Ｌ／ｈ分の固形成分が除去される。再生水の各成分は以下のようになる。
　ＴＤＳ：３６ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：１ｍｇ／Ｌ The permeated water obtained from the above low-pressure reverse osmosis unit 40 is supplied with the permeated water obtained from the forward osmosis device 70 and the purified water obtained from the distillation crystallization unit 80 and recovered. As a result, the water treatment apparatus 1 according to the first embodiment recovers the reclaimed water having a flow rate of (900 + 67 + 29 =) 996 L / h from the water to be treated having a flow rate of 1000 L / h, and a solid component of 4 L / h. Is removed. Each component of reclaimed water is as follows.
TDS: 36 mg / L, Ca: 0 mg / L, SiO 2 : 1 mg / L
　（第１変形例）
　次に、上述した第１の実施形態による水処理装置の第１変形例について説明する。図２は、第１の実施形態の第１変形例による水処理装置を模式的に示すブロック図である。図２に示すように、第１変形例による水処理装置２は、水処理装置１の正浸透装置７０の代わりに高圧逆浸透部９０が設けられる。 (First modification)
Next, a first modification of the water treatment apparatus according to the first embodiment described above will be described. FIG. 2 is a block diagram schematically showing a water treatment apparatus according to a first modification of the first embodiment. As shown in FIG. 2, the water treatment device 2 according to the first modification is provided with a high-pressure reverse osmosis unit 90 instead of the forward osmosis device 70 of the water treatment device 1.
　複数の水抽出部の他部または第２水抽出部としての高圧逆浸透部９０は、高圧逆浸透膜（高圧ＲＯ膜）を有して構成される。高圧ＲＯ膜としては例えば、商品名が「ＳＷＣ５－ＬＤ」または「ＳＷＣ５　ＭＡＸ」（いずれもHydranautics社製）や、商品名が「ＴＭ８２０Ｍ－４４０」、「ＴＭ８２０Ｒ－４４０」、または「ＴＭ８２０Ｖ－４４０」（いずれも東レ社製）などが用いられる。高圧逆浸透部９０においては、例えば８ＭＰａ程度の高圧力を作用させた逆浸透によって濃縮水から不純物濃度が低下された透過水を排出するとともに、濃縮水がさらに濃縮された高濃縮水を排出する。排出された透過水は再生水として、低圧逆浸透部４０から排出される透過水に合流される。一方、排出された高濃縮水は、蒸留晶析部８０に供給される。その他の構成は、第１の実施形態と同様である。 The high-pressure reverse osmosis section 90 as the other section of the plurality of water extraction sections or the second water extraction section is configured to have a high-pressure reverse osmosis membrane (high-pressure RO membrane). As the high-pressure RO membrane, for example, the product name is "SWC5-LD" or "SWC5 MAX" (both manufactured by Hydranautics), and the product names are "TM820M-440", "TM820R-440", or "TM820V-440". (Both made by Toray Industries, Inc.) are used. In the high-pressure reverse osmosis section 90, for example, permeated water having a reduced impurity concentration due to reverse osmosis applied with a high pressure of about 8 MPa is discharged, and highly concentrated water in which the concentrated water is further concentrated is discharged. .. The discharged permeated water is merged with the permeated water discharged from the low-pressure reverse osmosis unit 40 as reclaimed water. On the other hand, the discharged highly concentrated water is supplied to the distillation crystallization unit 80. Other configurations are the same as in the first embodiment.
　また、高圧ＲＯ膜にポリアミド系素材を用いる場合、アルカリ性の条件下での運転が可能になる。そのため、第２凝集沈殿部５０においてシリカの除去率が低い場合に、高圧逆浸透部９０をアルカリ性の条件下で運転することにより、高圧ＲＯ膜へのスケーリングを抑制することができる。この場合、上述した正浸透装置７０と同様に、透過水の排出側においてｐＨを５．５程度になるように調整できる。 Also, when a polyamide-based material is used for the high-pressure RO membrane, it can be operated under alkaline conditions. Therefore, when the removal rate of silica is low in the second coagulation-precipitation section 50, scaling to a high-pressure RO membrane can be suppressed by operating the high-pressure reverse osmosis section 90 under alkaline conditions. In this case, similarly to the forward osmosis device 70 described above, the pH can be adjusted to be about 5.5 on the discharge side of the permeated water.
　（第２実施例）
　（水処理方法）
　次に、以上のように構成された第１の変形例による水処理装置２を用いた水処理方法の第２実施例について説明する。なお、第２実施例における被処理水の条件については、第１実施例における被処理水と同様である。まず、第２実施例による水処理方法においては、第１凝集沈殿工程、第１ろ過工程、カルシウム除去工程、逆浸透工程、第２凝集沈殿工程、および第２ろ過工程については、第１実施例と同様である。 (Second Example)
(Water treatment method)
Next, a second embodiment of the water treatment method using the water treatment apparatus 2 according to the first modification configured as described above will be described. The conditions of the water to be treated in the second embodiment are the same as those in the water to be treated in the first embodiment. First, in the water treatment method according to the second embodiment, the first aggregation and precipitation step, the first filtration step, the calcium removal step, the reverse osmosis step, the second aggregation and precipitation step, and the second filtration step are described in the first embodiment. Is similar to.
　（高圧逆浸透工程）
　次に、第２ろ過工程に続いて、第２ろ過部６０から排出された濃縮水は、高圧逆浸透部９０に供給されて第２水抽出工程としての高圧逆浸透工程が行われる。高圧逆浸透部９０においては、濃縮水から透過水が得られるとともにさらに濃縮された高濃縮水が排出される。具体的に、高圧逆浸透部９０においては、高圧逆浸透膜（高圧ＲＯ膜）によって濃縮水から（１／２＝）５０％の再生水を回収される一方、（１／２＝）５０％の高濃縮水が排出される。 (High pressure reverse osmosis process)
Next, following the second filtration step, the concentrated water discharged from the second filtration section 60 is supplied to the high-pressure reverse osmosis section 90, and a high-pressure reverse osmosis step as a second water extraction step is performed. In the high-pressure reverse osmosis section 90, permeated water is obtained from the concentrated water, and more concentrated highly concentrated water is discharged. Specifically, in the high-pressure reverse osmosis section 90, (1/2 =) 50% of reclaimed water is recovered from the concentrated water by the high-pressure reverse osmosis membrane (high-pressure RO membrane), while (1/2 =) 50%. Highly concentrated water is discharged.
　第１実施例においては、高圧逆浸透部９０から（１００Ｌ／ｈ×５０％＝）５０Ｌ／ｈの流量で透過水が排出されて再生水として回収される。一方、高圧逆浸透部９０から（１００Ｌ／ｈ×５０％＝）５０Ｌ／ｈの流量で高濃縮水が排出される。高濃縮水の各成分は以下のようになる。
　ＴＤＳ：８０７００ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：２０ｍｇ／Ｌ In the first embodiment, the permeated water is discharged from the high-pressure reverse osmosis unit 90 at a flow rate of (100 L / h × 50% =) 50 L / h and recovered as reclaimed water. On the other hand, highly concentrated water is discharged from the high-pressure reverse osmosis unit 90 at a flow rate of (100 L / h × 50% =) 50 L / h. Each component of highly concentrated water is as follows.
TDS: 80700 mg / L, Ca: 0 mg / L, SiO 2 : 20 mg / L
　すなわち、濃縮水は、高圧逆浸透部９０によって、ＴＤＳが（８０７００／４０３５０＝）２倍、ＳｉＯ2が（２０／１０＝）２倍に濃縮される。これにより、第２実施例において、流量が１０００Ｌ／ｈの被処理水から、流量が５０Ｌ／ｈの高濃縮水が排出されることになる。一方、従来技術においては、流量が１０００Ｌ／ｈの被処理水に対して、排出される濃縮水の流量が２５０Ｌ／ｈである。すなわち、第２実施例による水処理装置２によれば、従来に比して被処理水をさらに５倍程度濃縮して排出でき、再生水の回収率を大幅に向上できる。 That is, in the concentrated water, TDS is concentrated (80700/40350 =) twice and SiO 2 is concentrated (20/10 =) twice by the high-pressure reverse osmosis unit 90. As a result, in the second embodiment, highly concentrated water having a flow rate of 50 L / h is discharged from the water to be treated having a flow rate of 1000 L / h. On the other hand, in the prior art, the flow rate of the concentrated water discharged is 250 L / h with respect to the water to be treated having a flow rate of 1000 L / h. That is, according to the water treatment apparatus 2 according to the second embodiment, the water to be treated can be further concentrated and discharged about 5 times as compared with the conventional case, and the recovery rate of the reclaimed water can be significantly improved.
　（蒸留晶析工程）
　高圧逆浸透部９０において濃縮された高濃縮水は、蒸留晶析部８０に供給されて蒸留晶析工程が行われる。蒸留晶析部８０においては、高濃縮水に対して、例えば１２０℃程度の温度で精製処理が行われ、精製された精製水は再生水として回収される。精製水から分離された固形成分としての塩は、外部に廃棄される。第２実施例においては、流量が５０Ｌ／ｈの高濃縮水から、４Ｌ／ｈ分の固形成分が除去されて、流量が４６Ｌ／ｈの精製水が再生水として回収される。 (Distillation crystallization step)
The highly concentrated water concentrated in the high-pressure reverse osmosis unit 90 is supplied to the distillation crystallization unit 80 to perform the distillation crystallization step. In the distillation crystallization unit 80, highly concentrated water is purified at a temperature of, for example, about 120 ° C., and the purified purified water is recovered as reclaimed water. The salt as a solid component separated from purified water is discarded to the outside. In the second embodiment, 4 L / h of solid components are removed from the highly concentrated water having a flow rate of 50 L / h, and purified water having a flow rate of 46 L / h is recovered as reclaimed water.
　以上の低圧逆浸透部４０から得られる透過水に、高圧逆浸透部９０から得られる透過水および蒸留晶析部８０から得られる精製水が供給されて回収される。これにより、第１変形例による水処理装置２によって、流量が１０００Ｌ／ｈの被処理水から、流量が（９００＋５０＋４６＝）９９６Ｌ／ｈの再生水が回収されるとともに、４Ｌ／ｈ分の固形成分が除去される。再生水の各成分は以下のようになる。
　ＴＤＳ：３６ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：１ｍｇ／Ｌ The permeated water obtained from the high-pressure reverse osmosis unit 40 and the purified water obtained from the distillation crystallization unit 80 are supplied to the permeated water obtained from the above low-pressure reverse osmosis unit 40 and recovered. As a result, the water treatment apparatus 2 according to the first modification recovers the reclaimed water having a flow rate of (900 + 50 + 46 =) 996 L / h from the water to be treated having a flow rate of 1000 L / h, and the solid component of 4 L / h is released. Will be removed. Each component of reclaimed water is as follows.
TDS: 36 mg / L, Ca: 0 mg / L, SiO 2 : 1 mg / L
　（従来技術による水処理装置）
　次に、以上説明した水処理装置１，２による効果を説明するために、従来技術による水処理装置について説明する。図３は、非特許文献１に記載された比較例としての従来技術による水処理装置を模式的に示すブロック図である。 (Water treatment equipment by conventional technology)
Next, in order to explain the effects of the water treatment devices 1 and 2 described above, the water treatment device according to the prior art will be described. FIG. 3 is a block diagram schematically showing a water treatment apparatus according to a prior art as a comparative example described in Non-Patent Document 1.
　図３に示すように、従来技術による水処理装置１００は、凝集沈殿部１１０、ろ過部１２０、軟水器１３０、低圧逆浸透部１４０、および蒸留晶析部１８０を有して構成される。凝集沈殿部１１０は、従来公知の凝集沈殿槽を有して構成される。ろ過部１２０は、従来公知の砂ろ過装置から構成される。軟水器１３０、低圧逆浸透部１４０、および蒸留晶析部１８０はそれぞれ、第１の実施形態による軟水器３０、低圧逆浸透部４０、および蒸留晶析部８０と同様の構成を有する。 As shown in FIG. 3, the water treatment apparatus 100 according to the prior art includes a coagulation sedimentation section 110, a filtration section 120, a water softener 130, a low pressure reverse osmosis section 140, and a distillation crystallization section 180. The coagulation sedimentation section 110 is configured to have a conventionally known coagulation sedimentation tank. The filtration unit 120 is composed of a conventionally known sand filtration device. The water softener 130, the low-pressure reverse osmosis unit 140, and the distillation crystallization unit 180 have the same configurations as the water softener 30, the low-pressure reverse osmosis unit 40, and the distillation crystallization unit 80 according to the first embodiment, respectively.
　（水処理方法）
　（比較例）
　次に、比較例として、従来技術による水処理装置１００を用いた水処理方法について説明する。なお、比較例における被処理水の条件は、第１および第２実施例における被処理水と同様であり、水処理装置１００に導入される被処理水の流量および各成分は以下のようになる。
　流量：１０００Ｌ／ｈ、ＴＤＳ：４０２２ｍｇ／Ｌ、Ｃａ：２６６ｍｇ／Ｌ、ＳｉＯ2：１２６ｍｇ／Ｌ (Water treatment method)
(Comparison example)
Next, as a comparative example, a water treatment method using the water treatment apparatus 100 according to the prior art will be described. The conditions of the water to be treated in the comparative example are the same as those of the water to be treated in the first and second examples, and the flow rate of the water to be treated and each component introduced into the water treatment apparatus 100 are as follows. ..
Flow rate: 1000 L / h, TDS: 4022 mg / L, Ca: 266 mg / L, SiO 2 : 126 mg / L
　（凝集沈殿工程）
　被処理水が水処理装置１００に導入されると凝集沈殿部１１０に供給されて、凝集沈殿工程が行われる。凝集沈殿部１１０の被処理水に添加されるｐＨ調整剤は、ＮａＯＨおよびＣａ（ＯＨ）2の少なくとも一方である。これにより被処理水のｐＨは、１０～１０．５程度に調整される。また、凝集沈殿部１１０の被処理水には、Ｃａを凝集沈殿させるＮａ2ＣＯ3であり、Ｎａ2ＣＯ3はＣａに対して当量だけ加えられる。凝集沈殿部１１０においては、被処理水からＣａＣＯ3が凝集されて除去される。凝集沈殿部１１０から排出される被処理水の各成分は以下のようになる。
　ＴＤＳ：４０２７ｍｇ／Ｌ、Ｃａ：５０ｍｇ／Ｌ、ＳｉＯ2：１２６ｍｇ／Ｌ
　すなわち、凝集沈殿部１１０においては、第１実施例と同様に、Ｃａが（２６６－５０＝）２１６ｍｇ／Ｌだけ、除去される。 (Coagulation sedimentation process)
When the water to be treated is introduced into the water treatment apparatus 100, it is supplied to the coagulation sedimentation section 110 to perform the coagulation sedimentation step. The pH adjuster added to the water to be treated in the coagulation sedimentation portion 110 is at least one of NaOH and Ca (OH) 2 . Thereby, the pH of the water to be treated is adjusted to about 10 to 10.5. Further , Na 2 CO 3 that coagulates and precipitates Ca is added to the water to be treated of the coagulation sedimentation portion 110 in an amount equivalent to Ca. In the coagulation sedimentation section 110, CaCO 3 is coagulated and removed from the water to be treated. Each component of the water to be treated discharged from the coagulation sedimentation portion 110 is as follows.
TDS: 4027 mg / L, Ca: 50 mg / L, SiO 2 : 126 mg / L
That is, in the coagulation sedimentation portion 110, Ca is removed by (266-50 =) 216 mg / L as in the first embodiment.
　（ろ過工程）
　凝集沈殿部１１０においてＣａＣＯ3が凝集沈殿されて得られた上澄み水は、被処理水としてろ過部１２０に供給されて、ろ過工程が行われる。 (Filtration process)
The supernatant water obtained by coagulating and precipitating CaCO 3 in the coagulation sedimentation section 110 is supplied to the filtration section 120 as water to be treated, and a filtration step is performed.
　（カルシウム除去工程）
　ろ過部１２０から得られた被処理水は、軟水器１３０に供給されてカルシウム除去工程が行われる。軟水器１３０においては被処理水からＣａが除去される。軟水器１３０から排出される被処理水の各成分は以下のようになる。
　ＴＤＳ：４１３４ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：１２６ｍｇ／Ｌ (Calcium removal process)
The water to be treated obtained from the filtration unit 120 is supplied to the water softener 130 to perform the calcium removal step. In the water softener 130, Ca is removed from the water to be treated. Each component of the water to be treated discharged from the water softener 130 is as follows.
TDS: 4134 mg / L, Ca: 0 mg / L, SiO 2 : 126 mg / L
　（低圧逆浸透工程）
　軟水器１３０においてＣａが除去された被処理水は、低圧逆浸透部１４０に供給されて低圧逆浸透工程が行われる。低圧逆浸透部４０においては、４．０ＭＰａ程度の圧力を作用させたＲＯ膜によって被処理水から７５％の再生水を回収する一方、２５％の濃縮水が排出される。なお、本発明者の知見によれば、低圧逆浸透部１４０に供給される被処理水にはシリカが含有されていることにより、再生水の回収率は高々７５％である。 (Low pressure reverse osmosis process)
The water to be treated from which Ca has been removed in the water softener 130 is supplied to the low-pressure reverse osmosis unit 140 to perform a low-pressure reverse osmosis step. In the low-pressure reverse osmosis section 40, 75% of the reclaimed water is recovered from the water to be treated by the RO membrane on which a pressure of about 4.0 MPa is applied, while 25% of the concentrated water is discharged. According to the findings of the present inventor, the recovery rate of reclaimed water is at most 75% because the water to be treated supplied to the low-pressure reverse osmosis unit 140 contains silica.
　比較例においては、低圧逆浸透部１４０から（１０００Ｌ／ｈ×７５％＝）７５０Ｌ／ｈの流量で被処理水が排出されて再生水として回収される。再生水の各成分は以下のようになる。
　ＴＤＳ：４０ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：３ｍｇ／Ｌ
　すなわち、低圧逆浸透部１４０において、ＴＤＳが（４０／４１３４≒）０．０１倍、ＳｉＯ2が（３／１２６≒）０．０２倍まで低減される。 In the comparative example, the water to be treated is discharged from the low-pressure reverse osmosis unit 140 at a flow rate of (1000 L / h × 75% =) 750 L / h and recovered as reclaimed water. Each component of reclaimed water is as follows.
TDS: 40 mg / L, Ca: 0 mg / L, SiO 2 : 3 mg / L
That is, in the low-pressure reverse osmosis section 140, TDS is reduced to (40/4134≈) 0.01 times and SiO 2 is reduced to (3/126≈) 0.02 times.
　一方、低圧逆浸透部１４０から（１０００Ｌ／ｈ×２５％＝）２５０Ｌ／ｈの流量で濃縮水が排出される。濃縮水の各成分は以下のようになる。
　ＴＤＳ：１６４２０ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：４９５ｍｇ／Ｌ
　すなわち、被処理水は低圧逆浸透部１４０において、ＴＤＳが（１６４２０／４１３４≒）３．９倍、ＳｉＯ2が（４９５／１２６≒）３．９倍に濃縮される。 On the other hand, concentrated water is discharged from the low-pressure reverse osmosis unit 140 at a flow rate of (1000 L / h × 25% =) 250 L / h. Each component of concentrated water is as follows.
TDS: 16420 mg / L, Ca: 0 mg / L, SiO 2 : 495 mg / L
That is, in the low-pressure reverse osmosis section 140, TDS is concentrated (16420/4134≈) 3.9 times and SiO 2 is concentrated (495/126≈) 3.9 times in the water to be treated.
　すなわち、従来技術による水処理装置１００においては、凝集沈殿部１１０によってＣａの一部を除去し、軟水器１３０によってＣａを完全に除去している。その上で、水処理装置１００においては、Ｃａが除去された被処理水に対して、低圧逆浸透部１４０をｐＨが１０～１０．５程度のアルカリ性の条件下で運転させることによって、シリカのスケーリングを抑制している（非特許文献１参照、ＨＥＲＯプロセス）。しかしながら、本発明者の知見によれば、低圧逆浸透部１４０をｐＨが１０～１０．５程度のアルカリ性の条件下で運転させても、シリカ濃度の析出限界は高々４００ｍｇ／Ｌ程度であって、低圧ＲＯ膜による濃縮倍率は、高々３～４倍程度である。 That is, in the water treatment apparatus 100 according to the prior art, a part of Ca is removed by the coagulation sedimentation portion 110, and Ca is completely removed by the water softener 130. Then, in the water treatment apparatus 100, the low-pressure reverse osmosis unit 140 is operated under alkaline conditions having a pH of about 10 to 10.5 with respect to the water to be treated from which Ca has been removed. Scaling is suppressed (see Non-Patent Document 1, HERO process). However, according to the findings of the present inventor, even if the low-pressure reverse osmosis unit 140 is operated under alkaline conditions having a pH of about 10 to 10.5, the precipitation limit of the silica concentration is at most about 400 mg / L. The concentration ratio by the low-pressure RO membrane is at most about 3 to 4 times.
　（蒸留晶析工程）
　低圧逆浸透部１４０によって得られた濃縮水は、蒸留晶析部１８０に供給されて蒸留晶析工程が行われる。蒸留晶析部１８０においては、スチームや電力が供給されて、１２０℃程度の温度で濃縮水に対して、蒸留処理および晶析処理の少なくとも一方、すなわち、従来公知の、蒸留処理および晶析処理、蒸留処理、または晶析処理などの精製処理が行われる。蒸留晶析部８０によって精製された精製水は再生水として回収される。精製水から分離された固形成分としての塩は、外部に廃棄される。比較例においては、流量が２５０Ｌ／ｈの濃縮水から、４Ｌ／ｈ分の固形成分が除去されて、流量が２４６Ｌ／ｈの精製水が再生水として回収される。 (Distillation crystallization step)
The concentrated water obtained by the low-pressure reverse osmosis unit 140 is supplied to the distillation crystallization unit 180 to perform the distillation crystallization step. In the distillation crystallization unit 180, steam or electric power is supplied to concentrate water at a temperature of about 120 ° C., and at least one of the distillation treatment and the crystallization treatment, that is, the conventionally known distillation treatment and crystallization treatment. , Distillation treatment, or purification treatment such as crystallization treatment. The purified water purified by the distillation crystallization unit 80 is recovered as reclaimed water. The salt as a solid component separated from purified water is discarded to the outside. In the comparative example, 4 L / h of solid components are removed from the concentrated water having a flow rate of 250 L / h, and purified water having a flow rate of 246 L / h is recovered as reclaimed water.
　以上により従来技術による水処理装置１００においては、流量が１０００Ｌ／ｈの被処理水から、流量が（７５０＋２４６＝）９９６Ｌ／ｈの再生水が回収されるとともに、４Ｌ／ｈ分の固形成分が除去される。再生水の各成分は以下のようになる。
　ＴＤＳ：３０ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：２ｍｇ／Ｌ As described above, in the water treatment apparatus 100 according to the prior art, the reclaimed water having a flow rate of (750 + 246 =) 996 L / h is recovered from the water to be treated having a flow rate of 1000 L / h, and the solid component of 4 L / h is removed. To. Each component of reclaimed water is as follows.
TDS: 30 mg / L, Ca: 0 mg / L, SiO 2 : 2 mg / L
　ここで、比較例で採用した水処理装置１００における電力、蒸気、およびコストをそれぞれ基準「１００」とした場合の、第１実施例および第２実施例でそれぞれ採用した水処理装置１，２における電力、蒸気、およびコストの比率を表１に示す。また、比較例、第１実施例、および第２実施例で採用した水処理装置１００，１，２における、単位排水量あたりの電力の使用量および蒸気の使用量を表２に示す。 Here, in the water treatment devices 1 and 2 adopted in the first embodiment and the second embodiment, respectively, when the electric power, steam, and cost in the water treatment device 100 adopted in the comparative example are set to the reference "100". Table 1 shows the ratio of electricity, steam, and cost. Table 2 shows the amount of electric power used and the amount of steam used per unit amount of wastewater in the water treatment devices 100, 1 and 2 adopted in the comparative example, the first embodiment, and the second embodiment.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１および表２から、第１実施例および第２実施例で使用した水処理装置１，２における電力がそれぞれ、比較例に比して２．３倍および２．０倍であることが分かる。これは、水処理装置１，２においては、水処理装置１００と比較して、正浸透装置７０や高圧逆浸透部９０が増加していることに起因している。一方、表１および表２から、水処理装置１，２においては、水処理装置１００と比較して、使用される蒸気の使用量がそれぞれ、比較例に比して０．２３倍および０．１５倍と大幅に低減されていることが分かる。これは、水処理装置１，２においては、低圧逆浸透部４０において、水処理装置１００の低圧逆浸透部１４０よりも被処理水が高濃度に濃縮されていることに起因すると考えられる。 From Tables 1 and 2, it can be seen that the electric power in the water treatment devices 1 and 2 used in the first example and the second embodiment is 2.3 times and 2.0 times, respectively, as compared with the comparative example. .. This is because in the water treatment devices 1 and 2, the number of the forward osmosis device 70 and the high-pressure reverse osmosis section 90 is increased as compared with the water treatment device 100. On the other hand, from Tables 1 and 2, in the water treatment appliances 1 and 2, the amount of steam used in the water treatment apparatus 100 is 0.23 times and 0, respectively, as compared with the comparative example. It can be seen that it is significantly reduced by 15 times. It is considered that this is because in the water treatment devices 1 and 2, the water to be treated is concentrated in the low pressure reverse osmosis section 40 at a higher concentration than that in the low pressure reverse osmosis section 140 of the water treatment device 100.
　蒸留処理や晶析処理は、蒸気や電力の消費量が大きい上に設備に要する費用も高コスト化しやすいため、蒸留晶析部８０は小型化することが望ましい。また、蒸気の生成にはエネルギーを要することから、蒸気の使用量を大幅に低減することによって、水処理装置１，２の運転に要する総エネルギーを水処理装置１００の運転に要する総エネルギーに比して大幅に低くできる。その結果、表１に示すように、第１の実施形態による水処理装置１，２によれば、設備や運転に要するコストを３５～４０％低減することが可能となる。 Distillation treatment and crystallization treatment consume a large amount of steam and electric power, and the cost required for equipment tends to be high. Therefore, it is desirable to reduce the size of the distillation crystallization unit 80. Further, since energy is required to generate steam, the total energy required for the operation of the water treatment devices 1 and 2 is compared with the total energy required for the operation of the water treatment device 100 by significantly reducing the amount of steam used. Can be significantly lowered. As a result, as shown in Table 1, according to the water treatment devices 1 and 2 according to the first embodiment, it is possible to reduce the cost required for equipment and operation by 35 to 40%.
　すなわち、従来技術による水処理方法においては、スケールの発生をある程度抑制することが可能になるが、特にＺＬＤにおいては、従来に比して大幅に高い濃縮を実現する必要があった。上述した従来技術（非特許文献１参照）においては、水処理装置の最終段に蒸留や晶析を行う処理部を設けることによって、ＺＬＤを実現しているが、必要となるエネルギーが大きくなるという問題があった。この問題は、ＺＬＤ以外の濃縮排水が生じる排水プロセスにおいても同様に存在する問題であり、必要となるエネルギーの低減が求められていた。これに対し、第１の実施形態によれば、不純物を含む被処理水から水を抽出する場合に、スケールの発生を抑制しつつ必要となるエネルギーを低減できる水処理装置１，２および水処理方法を提供することができる。 That is, in the water treatment method by the conventional technique, it is possible to suppress the generation of scale to some extent, but especially in ZLD, it is necessary to realize a significantly higher concentration than in the conventional method. In the above-mentioned prior art (see Non-Patent Document 1), ZLD is realized by providing a treatment unit for distillation and crystallization in the final stage of the water treatment apparatus, but the required energy is increased. There was a problem. This problem also exists in the wastewater process in which concentrated wastewater other than ZLD is generated, and reduction of the required energy has been required. On the other hand, according to the first embodiment, when water is extracted from the water to be treated containing impurities, the water treatment devices 1 and 2 and the water treatment can reduce the energy required while suppressing the generation of scale. A method can be provided.
　以上説明した第１の実施形態によれば、低圧逆浸透部４０の前段の第１凝集沈殿部１０において、Ｃａに加えてシリカを除去していることにより、低圧逆浸透部４０における低圧ＲＯ膜に生じるシリカの析出を抑制して、スケーリングの発生を抑制できる。これにより、低圧逆浸透部４０における濃縮倍率を向上できる。 According to the first embodiment described above, the low-pressure RO film in the low-pressure reverse osmosis section 40 is formed by removing silica in addition to Ca in the first coagulation-precipitation section 10 in the previous stage of the low-pressure reverse osmosis section 40. It is possible to suppress the precipitation of silica generated in the above and suppress the occurrence of scaling. Thereby, the concentration ratio in the low pressure reverse osmosis unit 40 can be improved.
　また、第１の実施形態によれば、低圧逆浸透部４０と正浸透装置７０や高圧逆浸透部９０との間に第２凝集沈殿部５０を設け、被処理水が濃縮された濃縮水からシリカを除去していることにより、正浸透装置７０や高圧逆浸透部９０におけるスケーリングの発生を抑制でき、濃縮倍率をさらに向上できる。また、低圧逆浸透部４０の前段に軟水器３０を設け、第１凝集沈殿部１０においてＣａが一部除去された被処理水からさらにＣａを除去していることにより、低圧逆浸透部４０におけるＣａに起因するスケーリングの発生を抑制できる。 Further, according to the first embodiment, a second coagulation sedimentation section 50 is provided between the low pressure reverse osmosis section 40 and the forward osmosis device 70 or the high pressure reverse osmosis section 90, and the concentrated water to be treated is concentrated. By removing the silica, the occurrence of scaling in the forward osmosis device 70 and the high-pressure reverse osmosis unit 90 can be suppressed, and the concentration ratio can be further improved. Further, a water softener 30 is provided in front of the low-pressure reverse osmosis section 40, and Ca is further removed from the water to be treated in which Ca is partially removed in the first coagulation sedimentation section 10, so that the low-pressure reverse osmosis section 40 The occurrence of scaling due to Ca can be suppressed.
　また、従来の水処理装置１００においては、例えば流量が２５０Ｌ／ｈの濃縮水を蒸留処理や晶析処理する必要があったのに対し、第１の実施形態およびその第１変形例による水処理装置１，２においては、流量が３３～５０Ｌ／ｈの高濃縮水を蒸留処理や晶析処理すれば良いので、総エネルギーの低減およびコストの低減が可能になる。 Further, in the conventional water treatment apparatus 100, for example, it is necessary to perform distillation treatment or crystallization treatment of concentrated water having a flow rate of 250 L / h, whereas water treatment according to the first embodiment and the first modification thereof. In the devices 1 and 2, since highly concentrated water having a flow rate of 33 to 50 L / h may be distilled or crystallized, the total energy can be reduced and the cost can be reduced.
　さらに、例えば特許文献２に記載の従来技術においては、２段階で凝集沈殿を行っているが、１段目においては分散剤を用いており、シリカを除去していないため、本発明に比して分散剤のコストが嵩む上、スケールの発生を抑制する能力が低く、高濃縮が困難であるという問題を有している。すなわち、特許文献２に記載の技術においては、シリカに起因したスケールの抑制のために分散剤を用いているが、分散剤は高コスト化しやすい問題点を有し、スケールの発生を抑制する効果が限定的であるという問題がある。 Further, for example, in the prior art described in Patent Document 2, coagulation and precipitation are performed in two steps, but in the first step, a dispersant is used and silica is not removed, so that the present invention is compared with the present invention. As a result, the cost of the dispersant is high, the ability to suppress the generation of scale is low, and high concentration is difficult. That is, in the technique described in Patent Document 2, a dispersant is used for suppressing scale caused by silica, but the dispersant has a problem that the cost tends to be high, and has an effect of suppressing the generation of scale. Has the problem of being limited.
　特許文献３に記載の従来技術においては、凝集沈殿を１段階で行っており、アルカリを用いてスケールの生成を抑制した後に凝集沈殿によってシリカを除去している。すなわち、特許文献３には、シリカにより発生するスケールを抑制するためにアルカリを用いる技術が開示されている。しかしながら、高アルカリ性の環境下においては、ＲＯ膜やＦＯ膜の劣化が促進されやすいことから、スケールの発生を抑制するためにアルカリを用いることはＲＯ膜やＦＯ膜にとっては好ましくない。また、後段に蒸発器が設けられている場合には、蒸発器において多量のシリカが固化する可能性が高く、蒸発缶にシリカが付着しやすくなって、蒸発器の負荷が高くなるという問題が生じる。 In the prior art described in Patent Document 3, coagulation precipitation is performed in one step, and silica is removed by coagulation precipitation after suppressing scale formation using alkali. That is, Patent Document 3 discloses a technique using an alkali to suppress the scale generated by silica. However, in a highly alkaline environment, deterioration of the RO film and the FO film is likely to be promoted, and therefore it is not preferable for the RO film and the FO film to use an alkali in order to suppress the generation of scale. Further, when an evaporator is provided in the subsequent stage, there is a high possibility that a large amount of silica is solidified in the evaporator, and silica is likely to adhere to the evaporator, which causes a problem that the load on the evaporator is increased. Occurs.
　特許文献４に記載の従来技術においては、凝集沈殿を１段階で行っており、凝集沈殿によってシリカを除去し、処理水をＲＯ膜に通水した後にＦＯ膜に通水させているため、ＦＯ膜におけるシリカスケールのリスクがあり，濃縮の向上には限界がある。これに対し、本発明においては、凝集沈殿をＲＯ膜の前段とＦＯ膜の前段との２段階で行い、いずれの凝集沈殿においてもシリカを除去していることにより、脱塩膜におけるスケールの発生を大幅に抑制でき、高濃縮を実現することが可能になる。 In the prior art described in Patent Document 4, coagulation and precipitation are performed in one step, silica is removed by coagulation and precipitation, and treated water is passed through the RO membrane and then through the FO membrane. There is a risk of silica scale in the membrane and there is a limit to the improvement in enrichment. On the other hand, in the present invention, coagulation and precipitation are performed in two stages, that is, the front stage of the RO membrane and the front stage of the FO membrane, and silica is removed in each of the coagulation precipitations, so that scale is generated in the desalted membrane. Can be significantly suppressed, and high concentration can be achieved.
　さらに、濃縮を行っていく過程で濃縮水量が極端に少なくなる場合には、高圧ＲＯ膜やＦＯ膜に最低濃縮水量を流すことが困難になる。濃縮流量を確保するために循環系を設けることがあるが、必要とするエネルギーが増加してしまうという問題が生じる。さらに、最低濃縮水量以下で運用しようとすると、飽和溶解度以下であっても、濃度分極の影響によってスケールの発生する可能性が高くなる。この点からも、上述した第１の実施形態による水処理装置１による２段階の凝集沈殿によってシリカを除去することが好ましい。 Furthermore, if the amount of concentrated water becomes extremely small in the process of concentration, it becomes difficult to flow the minimum amount of concentrated water through the high-pressure RO membrane or FO membrane. A circulatory system may be provided to secure the concentration flow rate, but there is a problem that the required energy increases. Furthermore, if an attempt is made to operate with a minimum concentration of water or less, there is a high possibility that scale will be generated due to the influence of concentration polarization even if the solubility is less than the saturated solubility. From this point as well, it is preferable to remove silica by two-step coagulation precipitation by the water treatment apparatus 1 according to the first embodiment described above.
　（第２の実施形態）
　次に、本発明の第２の実施形態による水処理装置について説明する。図４は、第２の実施形態による水処理装置を模式的に示すブロック図である。図４に示すように、第２の実施形態による水処理装置３は、第１の実施形態による水処理装置１と異なり、軟水器３０が設けられておらず、第１ろ過部２０から排出された被処理水に対してカルシウム分散剤が添加される機構（図示せず）が設けられる。その他の構成は、第１の実施形態による水処理装置１と同様である。 (Second embodiment)
Next, the water treatment apparatus according to the second embodiment of the present invention will be described. FIG. 4 is a block diagram schematically showing the water treatment apparatus according to the second embodiment. As shown in FIG. 4, unlike the water treatment device 1 according to the first embodiment, the water treatment device 3 according to the second embodiment is not provided with the water softener 30, and is discharged from the first filtration unit 20. A mechanism (not shown) is provided in which the calcium dispersant is added to the water to be treated. Other configurations are the same as those of the water treatment apparatus 1 according to the first embodiment.
　（水処理方法）
　（第３実施例）
　次に、以上のように構成された第２の実施形態による水処理装置３を用いた水処理方法の第３実施例について説明する。なお、第３実施例において水処理装置３に導入される被処理水については、第１，第２実施例における被処理水と同様である。また、第３実施例による水処理方法においては、第１凝集沈殿工程および第１ろ過工程については、第１実施例と同様である。
　第１ろ過工程後の被処理水の各成分は第１実施例と同様に以下のようになる。
　ＴＤＳ：４００５ｍｇ／Ｌ、Ｃａ：５０ｍｇ／Ｌ、ＳｉＯ2：１０ｍｇ／Ｌ (Water treatment method)
(Third Example)
Next, a third embodiment of the water treatment method using the water treatment apparatus 3 according to the second embodiment configured as described above will be described. The water to be treated introduced into the water treatment apparatus 3 in the third embodiment is the same as the water to be treated in the first and second embodiments. Further, in the water treatment method according to the third embodiment, the first coagulation sedimentation step and the first filtration step are the same as those in the first embodiment.
Each component of the water to be treated after the first filtration step is as follows as in the first embodiment.
TDS: 4005 mg / L, Ca: 50 mg / L, SiO 2 : 10 mg / L
　（カルシウム分散工程）
　第１ろ過部２０においてＰＡＣが除去された被処理水に対して、カルシウム分散剤を添加することによって、ＣａＳＯ4の生成を抑制するカルシウム分散工程が行われる。カルシウム分散剤の添加量は、分散剤の種類に依存するが、１ｍｇ／Ｌ以上１００ｍｇ／Ｌ以下が好ましい。なお、カルシウム分散剤以外にも、第１ろ過部２０において被処理水のｐＨを６．５から５．０に調整するＨ2ＳＯ4またはＨＣｌを添加する。なお、酸性溶液であれば、必ずしもこれらに限定されない。なお、カルシウム分散工程は、第１凝集沈殿工程の後であって、カルシウム塩などのスケーリングが発生しやすい工程の前に行うことが好ましい。 (Calcium dispersion process)
A calcium dispersion step of suppressing the production of CaSO 4 is performed by adding a calcium dispersant to the water to be treated from which the PAC has been removed in the first filtration unit 20. The amount of the calcium dispersant added depends on the type of the dispersant, but is preferably 1 mg / L or more and 100 mg / L or less. In addition to the calcium dispersant, H 2 SO 4 or HCl that adjusts the pH of the water to be treated from 6.5 to 5.0 is added in the first filtration unit 20. If it is an acidic solution, it is not necessarily limited to these. It is preferable that the calcium dispersion step is performed after the first coagulation-precipitation step and before the step in which scaling of the calcium salt or the like is likely to occur.
　（低圧逆浸透工程）
　カルシウム分散剤の添加によってＣａＳＯ4の生成が抑制された被処理水は、低圧逆浸透部４０に供給されて低圧逆浸透工程が行われる。低圧逆浸透部４０においては、ＴＤＳに依存する所定の圧力、ここでは例えば４．０ＭＰａの圧力を作用させた低圧ＲＯ膜によって被処理水から９０％の再生水が回収される一方、１０％の濃縮水が排出される。 (Low pressure reverse osmosis process)
The water to be treated, in which the formation of CaSO 4 is suppressed by the addition of the calcium dispersant, is supplied to the low-pressure reverse osmosis section 40 to perform the low-pressure reverse osmosis step. In the low-pressure reverse osmosis section 40, 90% of reclaimed water is recovered from the water to be treated by a low-pressure RO membrane on which a predetermined pressure depending on TDS, for example, 4.0 MPa is applied, while 10% concentration is performed. Water is drained.
　第３実施例においては、低圧逆浸透部４０から（１０００Ｌ／ｈ×９０％＝）９００Ｌ／ｈの流量で透過水が排出されて再生水として回収される。透過水の各成分は以下のようになる。
　ＴＤＳ：４０ｍｇ／Ｌ、Ｃａ：１ｍｇ／Ｌ未満、ＳｉＯ2：１ｍｇ／Ｌ
　すなわち、低圧逆浸透部４０において、ＴＤＳが（４０／４００５≒）０．０１倍、ＳｉＯ2が（１／１０≒）０．１倍まで低減される。 In the third embodiment, the permeated water is discharged from the low-pressure reverse osmosis unit 40 at a flow rate of (1000 L / h × 90% =) 900 L / h and recovered as reclaimed water. Each component of permeated water is as follows.
TDS: 40 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
That is, in the low-pressure reverse osmosis section 40, TDS is reduced to (40/4005≈) 0.01 times and SiO 2 is reduced to (1/10≈) 0.1 times.
　また、低圧逆浸透部４０から（１０００Ｌ／ｈ×１０％＝）１００Ｌ／ｈの流量で濃縮水が排出される。濃縮水の各成分は以下のようになる。
　ＴＤＳ：４００５０ｍｇ／Ｌ、Ｃａ：５００ｍｇ／Ｌ、ＳｉＯ2：１００ｍｇ／Ｌ
　すなわち、被処理水は低圧逆浸透部４０において、ＴＤＳが（４００５０／４００５＝）１０倍、Ｃａが（５００／５０＝）１０倍、ＳｉＯ2が（１００／１０＝）１０倍に濃縮される。 Further, concentrated water is discharged from the low-pressure reverse osmosis unit 40 at a flow rate of 100 L / h (1000 L / h × 10% =). Each component of concentrated water is as follows.
TDS: 40050 mg / L, Ca: 500 mg / L, SiO 2 : 100 mg / L
That is, the water to be treated is concentrated with TDS (40050/4005 =) 10 times, Ca (500/50 =) 10 times, and SiO 2 (100/10 =) 10 times in the low-pressure reverse osmosis unit 40. ..
　（第２凝集沈殿工程）
　低圧逆浸透部４０において濃縮された濃縮水は、第２凝集沈殿部５０に供給されて第２凝集沈殿工程が行われる。なお、第３実施例においては、被処理水にカルシウム分散剤が添加されてＣａが残存していることから、第２凝集沈殿部５０の濃縮水には、ｐＨ調整剤および凝集剤が添加される。添加されるｐＨ調整剤は第１凝集沈殿部１０に添加されたｐＨ調整剤と同様に、ＮａＯＨまたはＣａ（ＯＨ）2であるが、必ずしも限定されない。添加される凝集剤は、Ｃａおよびシリカを凝集させるために例えば、Ｎａ2ＣＯ3およびＰＡＣである。また、Ｎａ2ＣＯ3の濃度はＣａに対して当量とし、ＰＡＣの濃度はＳｉＯ2に対して２倍当量とすることが好ましいが、必ずしも限定されない。第２凝集沈殿部５０においては、この状態で３０分程度静置される。第２凝集沈殿部５０においては、被処理水からスケール成分として、ＣａＣＯ3およびシリカの一部が凝集されて除去される。 (Second coagulation sedimentation step)
The concentrated water concentrated in the low-pressure reverse osmosis section 40 is supplied to the second coagulation sedimentation section 50 to perform the second coagulation sedimentation step. In the third embodiment, since the calcium dispersant was added to the water to be treated and Ca remained, the pH adjuster and the flocculant were added to the concentrated water of the second coagulation sedimentation section 50. To. The pH adjuster added is NaOH or Ca (OH) 2 , similar to the pH adjuster added to the first coagulation sedimentation section 10, but is not necessarily limited. The coagulants added are, for example, Na 2 CO 3 and PAC for aggregating Ca and silica. Further, it is preferable that the concentration of Na 2 CO 3 is equivalent to Ca and the concentration of PAC is twice equivalent to SiO 2 , but it is not always limited. In the second coagulation sedimentation portion 50, it is allowed to stand in this state for about 30 minutes. In the second coagulation sedimentation section 50, CaCO 3 and a part of silica are coagulated and removed from the water to be treated as scale components.
　（第２ろ過工程）
　第２凝集沈殿部５０においてスケール成分としてＣａＣＯ3およびシリカが凝集沈殿されて得られた濃縮水は、第２ろ過部６０に供給されて、第２ろ過工程が行われる。第２ろ過部６０においては、Ｈ2ＳＯ4またはＨＣｌなどの酸が添加されて、ｐＨが５～６．５程度に調整される。第２ろ過部６０においては、濃縮水が３０分間以上静置されて、未反応のＰＡＣが除去される。
　第２ろ過部６０から排出される濃縮水の各成分は以下のようになる。
　ＴＤＳ：４００００ｍｇ／Ｌ、Ｃａ：５０ｍｇ／Ｌ、ＳｉＯ2：１０ｍｇ／Ｌ
　すなわち、第２凝集沈殿部５０および第２ろ過部６０によって、Ｃａが（５００－５０＝）４５０ｍｇ／Ｌ、ＳｉＯ2が（１００－１０＝）９０ｍｇ／Ｌ除去される。 (Second filtration step)
The concentrated water obtained by coagulating and precipitating CaCO 3 and silica as scale components in the second coagulation sedimentation section 50 is supplied to the second filtration section 60, and the second filtration step is performed. In the second filtration unit 60, an acid such as H 2 SO 4 or HCl is added to adjust the pH to about 5 to 6.5. In the second filtration unit 60, the concentrated water is allowed to stand for 30 minutes or more to remove unreacted PAC.
Each component of the concentrated water discharged from the second filtration unit 60 is as follows.
TDS: 40,000 mg / L, Ca: 50 mg / L, SiO 2 : 10 mg / L
That is, Ca is removed (500-50 =) 450 mg / L and SiO 2 is removed (100-10 =) 90 mg / L by the second coagulation sedimentation section 50 and the second filtration section 60.
　（正浸透処理工程）
　次に、第２ろ過部６０から排出された濃縮水は、正浸透装置７０に供給されて正浸透処理工程が行われ、濃縮水から再生水が得られるとともにさらに濃縮された高濃縮水が排出される。具体的に、正浸透装置７０においては、ＦＯ膜によって濃縮水から（２／３≒）６７％の再生水を回収する一方、（１／３≒）３３％の高濃縮水が排出される。 (Forward osmosis treatment process)
Next, the concentrated water discharged from the second filtration unit 60 is supplied to the forward osmosis device 70 to perform a forward osmosis treatment step, and the reclaimed water is obtained from the concentrated water and the further concentrated highly concentrated water is discharged. To. Specifically, in the forward osmosis apparatus 70, (2/3 ≈) 67% of reclaimed water is recovered from the concentrated water by the FO membrane, while (1/3 ≈) 33% of highly concentrated water is discharged.
　第３実施例においては、正浸透装置７０から（１００Ｌ／ｈ×６７％＝）６７Ｌ／ｈの流量で透過水が排出されて再生水として回収される。一方、正浸透装置７０から（１００Ｌ／ｈ×３３％＝）３３Ｌ／ｈの流量で高濃縮水が排出される。高濃縮水の各成分は以下のようになる。
　ＴＤＳ：１２００００ｍｇ／Ｌ、Ｃａ：１５０ｍｇ／Ｌ、ＳｉＯ2：３０ｍｇ／Ｌ
　すなわち、濃縮水は、正浸透装置７０において、ＴＤＳが（１２００００／４００００＝）３倍、Ｃａが（１５０／５０＝）３倍、ＳｉＯ2が（３０／１０＝）３倍に濃縮される。また、第３実施例において、流量が１０００Ｌ／ｈの被処理水からは、流量が３３Ｌ／ｈの高濃縮水が排出できることになるので、第３実施例において採用した水処理装置３によれば、従来技術に比して被処理水をさらに７．６倍程度濃縮して排出でき、再生水の回収率を大幅に向上できる。 In the third embodiment, the permeated water is discharged from the forward osmosis device 70 at a flow rate of (100 L / h × 67% =) 67 L / h and recovered as reclaimed water. On the other hand, highly concentrated water is discharged from the forward osmosis device 70 at a flow rate of (100 L / h × 33% =) 33 L / h. Each component of highly concentrated water is as follows.
TDS: 120,000 mg / L, Ca: 150 mg / L, SiO 2 : 30 mg / L
That is, in the concentrated water, TDS is concentrated (120,000/40000 =) 3 times, Ca is concentrated (150/50 =) 3 times, and SiO 2 is concentrated (30/10 =) 3 times in the forward osmosis apparatus 70. Further, in the third embodiment, highly concentrated water having a flow rate of 33 L / h can be discharged from the water to be treated having a flow rate of 1000 L / h. Therefore, according to the water treatment device 3 adopted in the third embodiment. The water to be treated can be further concentrated and discharged about 7.6 times as compared with the conventional technique, and the recovery rate of reclaimed water can be significantly improved.
　（蒸留晶析工程）
　正浸透装置７０において濃縮された高濃縮水は、第１実施例と同様に蒸留晶析部８０に供給されて蒸留晶析工程が行われる。蒸留晶析部８０によって精製された精製水は再生水として回収される。精製水から分離された固形成分としての塩は、外部に廃棄される。第３実施例においては、流量が３３Ｌ／ｈの高濃縮水から、４Ｌ／ｈ分の固形成分が除去されて、流量が２９Ｌ／ｈの精製水が再生水として回収される。 (Distillation crystallization step)
The highly concentrated water concentrated in the forward osmosis apparatus 70 is supplied to the distillation crystallization unit 80 in the same manner as in the first embodiment, and the distillation crystallization step is performed. The purified water purified by the distillation crystallization unit 80 is recovered as reclaimed water. The salt as a solid component separated from purified water is discarded to the outside. In the third embodiment, 4 L / h of solid components are removed from the highly concentrated water having a flow rate of 33 L / h, and purified water having a flow rate of 29 L / h is recovered as reclaimed water.
　以上の低圧逆浸透部４０から得られる透過水に、正浸透装置７０から得られる透過水および蒸留晶析部８０から得られる精製水が供給されて回収される。これにより、第３実施例においては、第２の実施形態による水処理装置３によって、流量が１０００Ｌ／ｈの被処理水から、流量が（９００＋６７＋２９＝）９９６Ｌ／ｈの再生水が回収されるとともに、４Ｌ／ｈ分の固形成分が除去される。再生水の各成分は以下のようになる。
　ＴＤＳ：３６ｍｇ／Ｌ、Ｃａ：１ｍｇ／Ｌ未満、ＳｉＯ2：１ｍｇ／Ｌ The permeated water obtained from the above low-pressure reverse osmosis unit 40 is supplied with the permeated water obtained from the forward osmosis device 70 and the purified water obtained from the distillation crystallization unit 80 and recovered. As a result, in the third embodiment, the water treatment apparatus 3 according to the second embodiment recovers the reclaimed water having a flow rate of (900 + 67 + 29 =) 996 L / h from the water to be treated having a flow rate of 1000 L / h. 4 L / h of solid components are removed. Each component of reclaimed water is as follows.
TDS: 36 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
　（第２変形例）
　次に、上述した第２の実施形態による水処理装置の第２変形例について説明する。図５は、第２変形例による水処理装置を模式的に示すブロック図である。図５に示すように、第２変形例による水処理装置４は、水処理装置３の正浸透装置７０の代わりに第１変形例と同様の高圧逆浸透部９０が設けられる。 (Second modification)
Next, a second modification of the water treatment apparatus according to the second embodiment described above will be described. FIG. 5 is a block diagram schematically showing a water treatment apparatus according to a second modification. As shown in FIG. 5, the water treatment device 4 according to the second modification is provided with the same high-pressure reverse osmosis unit 90 as the first modification instead of the forward osmosis device 70 of the water treatment device 3.
　高圧逆浸透部９０においては、例えば８ＭＰａ程度の高圧力を作用させた逆浸透によって濃縮水から不純物濃度が低下された透過水を排出するとともに、濃縮水がさらに濃縮された高濃縮水を排出する。排出された透過水は再生水として、低圧逆浸透部４０から排出される透過水に合流される。一方、排出された高濃縮水は、蒸留晶析部８０に供給される。その他の構成は、第２の実施形態と同様である。 In the high-pressure reverse osmosis section 90, for example, permeated water having a reduced impurity concentration due to reverse osmosis applied with a high pressure of about 8 MPa is discharged, and highly concentrated water in which the concentrated water is further concentrated is discharged. .. The discharged permeated water is merged with the permeated water discharged from the low-pressure reverse osmosis unit 40 as reclaimed water. On the other hand, the discharged highly concentrated water is supplied to the distillation crystallization unit 80. Other configurations are the same as in the second embodiment.
　（水処理方法）
　（第４実施例）
　次に、以上のように構成された第２変形例による水処理装置４を用いた水処理方法の第４実施例について説明する。なお、第４実施例における被処理水は、第１～第３実施例における被処理水と同様である。まず、第４実施例による水処理方法においては、第１凝集沈殿工程、第１ろ過工程、カルシウム分散工程、低圧逆浸透工程、第２凝集沈殿工程、および第２ろ過工程については、第３実施例と同様である。 (Water treatment method)
(Fourth Example)
Next, a fourth embodiment of the water treatment method using the water treatment device 4 according to the second modification configured as described above will be described. The water to be treated in the fourth embodiment is the same as the water to be treated in the first to third examples. First, in the water treatment method according to the fourth embodiment, the first coagulation / precipitation step, the first filtration step, the calcium dispersion step, the low-pressure reverse osmosis step, the second coagulation / precipitation step, and the second filtration step are carried out in the third. Similar to the example.
　（高圧逆浸透工程）
　次に、第２ろ過工程に続いて、第２ろ過部６０から排出された濃縮水は、高圧逆浸透部９０に供給されて高圧逆浸透工程が行われる。高圧逆浸透部９０においては、濃縮水から透過水が得られるとともにさらに濃縮された高濃縮水が排出される。 (High pressure reverse osmosis process)
Next, following the second filtration step, the concentrated water discharged from the second filtration section 60 is supplied to the high-pressure reverse osmosis section 90 to perform the high-pressure reverse osmosis step. In the high-pressure reverse osmosis section 90, permeated water is obtained from the concentrated water, and more concentrated highly concentrated water is discharged.
　具体的に、高圧逆浸透部９０においては、高圧逆浸透膜（高圧ＲＯ膜）によって濃縮水から（１／２＝）５０％の透過水が再生水として回収される一方、（１／２＝）５０％の高濃縮水が排出される。第４実施例においては、高圧逆浸透部９０から（１００Ｌ／ｈ×５０％＝）５０Ｌ／ｈの流量で透過水が排出されて再生水として回収される。一方、高圧逆浸透部９０から（１００Ｌ／ｈ×５０％＝）５０Ｌ／ｈの流量で高濃縮水が排出される。高濃縮水の各成分は以下のようになる。
　ＴＤＳ：８００００ｍｇ／Ｌ、Ｃａ：１００ｍｇ／Ｌ、ＳｉＯ2：２０ｍｇ／Ｌ Specifically, in the high-pressure reverse osmosis section 90, (1/2 =) 50% of permeated water is recovered as reclaimed water from the concentrated water by the high-pressure reverse osmosis membrane (high-pressure RO membrane), while (1/2 =). 50% highly concentrated water is discharged. In the fourth embodiment, the permeated water is discharged from the high-pressure reverse osmosis unit 90 at a flow rate of (100 L / h × 50% =) 50 L / h and recovered as reclaimed water. On the other hand, highly concentrated water is discharged from the high-pressure reverse osmosis unit 90 at a flow rate of (100 L / h × 50% =) 50 L / h. Each component of highly concentrated water is as follows.
TDS: 80,000 mg / L, Ca: 100 mg / L, SiO 2 : 20 mg / L
　すなわち、濃縮水は、高圧逆浸透部９０によって、ＴＤＳが（８００００／４００００＝）２倍、Ｃａが（１００／５０＝）２倍、ＳｉＯ2が（２０／１０＝）２倍に濃縮される。これにより、第４実施例において、流量が１０００Ｌ／ｈの被処理水から、流量が５０Ｌ／ｈの高濃縮水が排出されることになる。一方、従来技術においては、流量が１０００Ｌ／ｈの被処理水に対して、排出される濃縮水の流量が２５０Ｌ／ｈである。すなわち、第２実施例による水処理装置２によれば、従来に比して被処理水をさらに５倍程度濃縮して排出でき、再生水の回収率を大幅に向上できる。 That is, in the concentrated water, TDS is (80,000 / 40,000 =) twice, Ca is (100/50 =) twice, and SiO 2 is (20/10 =) twice concentrated by the high-pressure reverse osmosis unit 90. .. As a result, in the fourth embodiment, highly concentrated water having a flow rate of 50 L / h is discharged from the water to be treated having a flow rate of 1000 L / h. On the other hand, in the prior art, the flow rate of the concentrated water discharged is 250 L / h with respect to the water to be treated having a flow rate of 1000 L / h. That is, according to the water treatment apparatus 2 according to the second embodiment, the water to be treated can be further concentrated and discharged about 5 times as compared with the conventional case, and the recovery rate of the reclaimed water can be significantly improved.
　（蒸留晶析工程）
　高圧逆浸透部９０において濃縮された高濃縮水は、蒸留晶析部８０に供給されて蒸留晶析工程が行われる。蒸留晶析部８０においては、高濃縮水に対して、例えば１２０℃程度の温度で精製処理が行われ、精製された精製水は再生水として回収される。精製水から分離された固形成分としての塩は、外部に廃棄される。第２実施例においては、流量が５０Ｌ／ｈの高濃縮水から、４Ｌ／ｈ分の固形成分が除去されて、流量が４６Ｌ／ｈの精製水が再生水として回収される。 (Distillation crystallization step)
The highly concentrated water concentrated in the high-pressure reverse osmosis unit 90 is supplied to the distillation crystallization unit 80 to perform the distillation crystallization step. In the distillation crystallization unit 80, highly concentrated water is purified at a temperature of, for example, about 120 ° C., and the purified purified water is recovered as reclaimed water. The salt as a solid component separated from purified water is discarded to the outside. In the second embodiment, 4 L / h of solid components are removed from the highly concentrated water having a flow rate of 50 L / h, and purified water having a flow rate of 46 L / h is recovered as reclaimed water.
　以上の低圧逆浸透部４０から得られる透過水に、高圧逆浸透部９０から得られる透過水および蒸留晶析部８０から得られる精製水が供給されて回収される。これにより、第４実施例においては、第２変形例による水処理装置４によって、流量が１０００Ｌ／ｈの被処理水から、流量が（９００＋５０＋４６＝）９９６Ｌ／ｈの再生水が回収されるとともに、４Ｌ／ｈ分の固形成分が除去される。再生水の各成分は第２の実施形態と同様に、以下のようになる。
　ＴＤＳ：３６ｍｇ／Ｌ、Ｃａ：１ｍｇ／Ｌ未満、ＳｉＯ2：１ｍｇ／Ｌ The permeated water obtained from the high-pressure reverse osmosis unit 40 and the purified water obtained from the distillation crystallization unit 80 are supplied to the permeated water obtained from the above low-pressure reverse osmosis unit 40 and recovered. As a result, in the fourth embodiment, the water treatment apparatus 4 according to the second modification recovers the reclaimed water having a flow rate of (900 + 50 + 46 =) 996 L / h from the water to be treated having a flow rate of 1000 L / h, and 4 L. The solid component of / h is removed. Each component of the reclaimed water is as follows, as in the second embodiment.
TDS: 36 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
　以上説明した第２の実施形態によれば、低圧逆浸透部４０の前段の第１凝集沈殿部１０において、Ｃａに加えてシリカを除去し、低圧逆浸透部４０と正浸透装置７０や高圧逆浸透部９０との間に第２凝集沈殿部５０を設け、被処理水が濃縮された濃縮水からシリカを除去していることにより、第１の実施形態と同様の効果を得ることができる。 According to the second embodiment described above, silica is removed in addition to Ca in the first coagulation sedimentation section 10 in the previous stage of the low pressure reverse osmosis section 40, and the low pressure reverse osmosis section 40, the forward osmosis device 70, and the high pressure reverse osmosis section 40 are removed. By providing the second coagulation sedimentation portion 50 between the permeation portion 90 and removing silica from the concentrated water in which the water to be treated is concentrated, the same effect as in the first embodiment can be obtained.
　（第３の実施形態）
　次に、本発明の第３の実施形態による水処理装置について説明する。図６は、第３の実施形態による水処理装置を模式的に示すブロック図である。図３に示すように、第３の実施形態による水処理装置３は、第２の実施形態による水処理装置３と異なり、蒸留晶析部８０が設けられておらず、正浸透装置から排出される高濃縮水は、濃縮排水として廃棄される。その他の構成は、第２の実施形態による水処理装置３と同様である。 (Third Embodiment)
Next, the water treatment apparatus according to the third embodiment of the present invention will be described. FIG. 6 is a block diagram schematically showing the water treatment apparatus according to the third embodiment. As shown in FIG. 3, unlike the water treatment device 3 according to the second embodiment, the water treatment device 3 according to the third embodiment is not provided with the distillation crystallization unit 80 and is discharged from the forward osmosis device. Highly concentrated water is discarded as concentrated wastewater. Other configurations are the same as those of the water treatment apparatus 3 according to the second embodiment.
　（第５実施例）
　（水処理方法）
　次に、以上のように構成された第３の実施形態による水処理装置５を用いた水処理方法の第５実施例について説明する。なお、第５実施例において水処理装置５に導入される被処理水については、第１～第４実施例における被処理水と同様である。また、第５実施例による水処理方法においては、第１凝集沈殿工程、第１ろ過工程、カルシウム分散工程、低圧逆浸透工程、第２凝集沈殿工程、第２ろ過工程、および正浸透処理工程については、第３実施例と同様である一方、蒸留晶析工程が行われない。 (Fifth Example)
(Water treatment method)
Next, a fifth embodiment of the water treatment method using the water treatment apparatus 5 according to the third embodiment configured as described above will be described. The water to be treated introduced into the water treatment apparatus 5 in the fifth embodiment is the same as the water to be treated in the first to fourth embodiments. Further, in the water treatment method according to the fifth embodiment, the first coagulation sedimentation step, the first filtration step, the calcium dispersion step, the low pressure back permeation step, the second coagulation sedimentation step, the second filtration step, and the normal permeation treatment step. Is the same as in the third embodiment, but the distillation crystallization step is not performed.
　第５実施例においては、正浸透処理工程において正浸透装置７０から排出される被処理水の流量は３３Ｌ／ｈであり、各成分は以下のようになる。
　ＴＤＳ：１２００００ｍｇ／Ｌ、Ｃａ：１５０ｍｇ／Ｌ、ＳｉＯ2：３０ｍｇ／Ｌ In the fifth embodiment, the flow rate of the water to be treated discharged from the forward osmosis apparatus 70 in the forward osmosis treatment step is 33 L / h, and each component is as follows.
TDS: 120,000 mg / L, Ca: 150 mg / L, SiO 2 : 30 mg / L
　第５実施例においては、正浸透装置７０から（１００Ｌ／ｈ×６７％＝）６７Ｌ／ｈの流量で透過水が排出されて再生水として回収される。一方、正浸透装置７０から（１００Ｌ／ｈ×３３％＝）３３Ｌ／ｈの流量で高濃縮水が排出される。高濃縮水の各成分は以下のようになる。
　ＴＤＳ：１２００００ｍｇ／Ｌ、Ｃａ：１５０ｍｇ／Ｌ、ＳｉＯ2：３０ｍｇ／Ｌ
　すなわち、濃縮水は、正浸透装置７０において、ＴＤＳが（１２００００／４００００＝）３倍、Ｃａが（１５０／５０＝）３倍、ＳｉＯ2が（３０／１０＝）３倍に濃縮される。また、第５実施例において、流量が１０００Ｌ／ｈの被処理水からは、流量が３３Ｌ／ｈの高濃縮水が排出できることになるので、第５実施例において採用した水処理装置５によれば、従来技術に比して被処理水をさらに７．６倍程度濃縮して排出でき、再生水の回収率を大幅に向上できる。 In the fifth embodiment, the permeated water is discharged from the forward osmosis device 70 at a flow rate of (100 L / h × 67% =) 67 L / h and recovered as reclaimed water. On the other hand, highly concentrated water is discharged from the forward osmosis device 70 at a flow rate of (100 L / h × 33% =) 33 L / h. Each component of highly concentrated water is as follows.
TDS: 120,000 mg / L, Ca: 150 mg / L, SiO 2 : 30 mg / L
That is, in the concentrated water, TDS is concentrated (120,000/40000 =) 3 times, Ca is concentrated (150/50 =) 3 times, and SiO 2 is concentrated (30/10 =) 3 times in the forward osmosis apparatus 70. Further, in the fifth embodiment, highly concentrated water having a flow rate of 33 L / h can be discharged from the water to be treated having a flow rate of 1000 L / h. Therefore, according to the water treatment device 5 adopted in the fifth embodiment. The water to be treated can be further concentrated and discharged about 7.6 times as compared with the conventional technique, and the recovery rate of reclaimed water can be significantly improved.
　また、第５実施例においては、正浸透装置７０から排出された高濃縮水は廃棄され、低圧逆浸透部４０から得られる透過水に、正浸透装置７０から得られる透過水が供給されて回収される。これにより、第５実施例においては、第３の実施形態による水処理装置５によって、流量が１０００Ｌ／ｈの被処理水から、流量が（９００＋６７＝）９６７Ｌ／ｈの再生水が回収されるとともに、３３Ｌ／ｈの高濃縮水が廃棄される。再生水の各成分は以下のようになる。
　ＴＤＳ：３７ｍｇ／Ｌ、Ｃａ：１ｍｇ／Ｌ未満、ＳｉＯ2：１ｍｇ／Ｌ Further, in the fifth embodiment, the highly concentrated water discharged from the forward osmosis device 70 is discarded, and the permeated water obtained from the forward osmosis device 70 is supplied to the permeated water obtained from the low pressure reverse osmosis unit 40 and recovered. Will be done. As a result, in the fifth embodiment, the water treatment apparatus 5 according to the third embodiment recovers the reclaimed water having a flow rate of (900 + 67 =) 967 L / h from the water to be treated having a flow rate of 1000 L / h. Highly concentrated water of 33 L / h is discarded. Each component of reclaimed water is as follows.
TDS: 37 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
　（第３変形例）
　次に、上述した第３の実施形態による水処理装置の第３変形例について説明する。図７は、第３変形例による水処理装置を模式的に示すブロック図である。図７に示すように、第３変形例による水処理装置６は、水処理装置３の正浸透装置７０の代わりに第１，第２変形例と同様の高圧逆浸透部９０が設けられる。高圧逆浸透部９０においては、例えば８ＭＰａ程度の高圧力を作用させた逆浸透によって濃縮水から不純物濃度が低下された透過水を排出して再生水として回収されるとともに、濃縮水がさらに濃縮された高濃縮水は濃縮排水として廃棄される。その他の構成は、第３の実施形態と同様である。 (Third modification example)
Next, a third modification of the water treatment apparatus according to the third embodiment described above will be described. FIG. 7 is a block diagram schematically showing a water treatment apparatus according to a third modification. As shown in FIG. 7, the water treatment device 6 according to the third modification is provided with the same high-pressure reverse osmosis section 90 as the first and second modifications instead of the forward osmosis device 70 of the water treatment device 3. In the high-pressure reverse osmosis section 90, permeated water having a reduced impurity concentration was discharged from the concentrated water by reverse osmosis in which a high pressure of, for example, about 8 MPa was applied, and recovered as reclaimed water, and the concentrated water was further concentrated. Highly concentrated water is discarded as concentrated wastewater. Other configurations are the same as in the third embodiment.
　（水処理方法）
　（第６実施例）
　次に、以上のように構成された第３変形例による水処理装置６を用いた水処理方法の第６実施例について説明する。なお、第６実施例における被処理水は、第１～第５実施例における被処理水と同様である。まず、第６実施例による水処理方法においては、第１凝集沈殿工程、第１ろ過工程、カルシウム分散工程、低圧逆浸透工程、第２凝集沈殿工程、および第２ろ過工程については、第３の実施形態と同様である。また、第６実施例による水処理方法においては、高圧逆浸透工程については、第１，第２変形例と同様である。 (Water treatment method)
(6th Example)
Next, a sixth embodiment of the water treatment method using the water treatment apparatus 6 according to the third modification configured as described above will be described. The water to be treated in the sixth embodiment is the same as the water to be treated in the first to fifth examples. First, in the water treatment method according to the sixth embodiment, the first coagulation / precipitation step, the first filtration step, the calcium dispersion step, the low-pressure reverse osmosis step, the second coagulation / precipitation step, and the second filtration step are described in the third. It is the same as the embodiment. Further, in the water treatment method according to the sixth embodiment, the high pressure reverse osmosis step is the same as that of the first and second modified examples.
　第６実施例においては、流量が１０００Ｌ／ｈの被処理水から、流量が５０Ｌ／ｈの高濃縮水が排出される。一方、従来技術においては、流量が１０００Ｌ／ｈの被処理水に対して、排出される濃縮水の流量が２５０Ｌ／ｈである。すなわち、第６実施例による水処理装置６によれば、従来に比して被処理水を５倍程度濃縮して排出でき、再生水の回収率を大幅に向上できる。 In the sixth embodiment, highly concentrated water having a flow rate of 50 L / h is discharged from the water to be treated having a flow rate of 1000 L / h. On the other hand, in the prior art, the flow rate of the concentrated water discharged is 250 L / h with respect to the water to be treated having a flow rate of 1000 L / h. That is, according to the water treatment apparatus 6 according to the sixth embodiment, the water to be treated can be concentrated and discharged about 5 times as compared with the conventional case, and the recovery rate of the reclaimed water can be significantly improved.
　以上の低圧逆浸透部４０から得られる透過水に、高圧逆浸透部９０から得られる透過水が供給されて回収される。これにより、第６実施例においては、第３変形例による水処理装置６によって、流量が１０００Ｌ／ｈの被処理水から、流量が（９００＋５０＝）９５０Ｌ／ｈの再生水が回収されるとともに、５０Ｌ／ｈの濃縮排水が廃棄される。高圧逆浸透部９０から回収される透過水の流量が、正浸透装置７０から回収される透過水の流量より低いことにより、ＴＤＳは第３の実施形態に比して大きくなる。そのため、再生水の各成分は以下のようになる。
　ＴＤＳ：３８ｍｇ／Ｌ、Ｃａ：１ｍｇ／Ｌ未満、ＳｉＯ2：１ｍｇ／Ｌ The permeated water obtained from the high-pressure reverse osmosis unit 90 is supplied to the permeated water obtained from the above low-pressure reverse osmosis unit 40 and recovered. As a result, in the sixth embodiment, the water treatment apparatus 6 according to the third modification recovers the reclaimed water having a flow rate of (900 + 50 =) 950 L / h from the water to be treated having a flow rate of 1000 L / h, and 50 L. The concentrated wastewater of / h is discarded. Since the flow rate of the permeated water recovered from the high-pressure reverse osmosis unit 90 is lower than the flow rate of the permeated water recovered from the forward osmosis device 70, the TDS becomes larger than that of the third embodiment. Therefore, each component of reclaimed water is as follows.
TDS: 38 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
　以上説明した第３の実施形態によれば、低圧逆浸透部４０の前段に第１凝集沈殿部１０を設け、低圧逆浸透部４０と正浸透装置７０や高圧逆浸透部９０との間に第２凝集沈殿部５０を設けていることにより、第１および第２の実施形態と同様の効果を得ることができる。 According to the third embodiment described above, the first coagulation sedimentation section 10 is provided in front of the low pressure reverse osmosis section 40, and the low pressure reverse osmosis section 40 is located between the forward osmosis device 70 and the high pressure reverse osmosis section 90. By providing the two coagulation sedimentation portions 50, the same effects as those of the first and second embodiments can be obtained.
　（第４の実施形態）
　次に、本発明の第４の実施形態による水処理装置について説明する。図８は、第４の実施形態による水処理装置を模式的に示すブロック図である。図８に示すように、第４の実施形態による水処理装置３は、第１の実施形態による水処理装置１と異なり、軟水器３０が、低圧逆浸透部４０の前段に設けられておらず、正浸透装置７０の前段に設けられている。なお、第４の実施形態において軟水器３０はさらに、第２ろ過部６０の後段に設けられている。その他の構成は、第１の実施形態による水処理装置１と同様である。 (Fourth Embodiment)
Next, the water treatment apparatus according to the fourth embodiment of the present invention will be described. FIG. 8 is a block diagram schematically showing the water treatment apparatus according to the fourth embodiment. As shown in FIG. 8, unlike the water treatment device 1 according to the first embodiment, the water treatment device 3 according to the fourth embodiment does not have the water softener 30 provided in front of the low pressure reverse osmosis unit 40. , Is provided in front of the forward osmosis device 70. In the fourth embodiment, the water softener 30 is further provided after the second filtration unit 60. Other configurations are the same as those of the water treatment apparatus 1 according to the first embodiment.
　（水処理方法）
　（第７実施例）
　次に、以上のように構成された第４の実施形態による水処理装置７を用いた水処理方法の第７実施例について説明する。なお、第７実施例において水処理装置７に導入される被処理水については、第１～第６実施例における被処理水と同様である。また、第７実施例による水処理方法においては、第１凝集沈殿工程および第１ろ過工程については、第１実施例と同様である。
　第１ろ過工程後の被処理水の各成分は第１実施例と同様に以下のようになる。
　ＴＤＳ：４００５ｍｇ／Ｌ、Ｃａ：５０ｍｇ／Ｌ、ＳｉＯ2：１０ｍｇ／Ｌ (Water treatment method)
(7th Example)
Next, a seventh embodiment of the water treatment method using the water treatment apparatus 7 according to the fourth embodiment configured as described above will be described. The water to be treated introduced into the water treatment apparatus 7 in the seventh embodiment is the same as the water to be treated in the first to sixth embodiments. Further, in the water treatment method according to the seventh embodiment, the first coagulation sedimentation step and the first filtration step are the same as those in the first embodiment.
Each component of the water to be treated after the first filtration step is as follows as in the first embodiment.
TDS: 4005 mg / L, Ca: 50 mg / L, SiO 2 : 10 mg / L
　（低圧逆浸透工程）
　第１ろ過部２０においてＰＡＣが除去された被処理水は、低圧逆浸透部４０に供給されて低圧逆浸透工程が行われる。低圧逆浸透部４０においては、ＴＤＳに依存する所定の圧力、例えば４．０ＭＰａの圧力を作用させた低圧ＲＯ膜によって被処理水から９０％の再生水が回収される一方、１０％の濃縮水が排出される。ここで、第１凝集沈殿部１０においてシリカが除去されていることにより、低圧逆浸透部４０による再生水の回収率を９０％まで向上させることができる。 (Low pressure reverse osmosis process)
The water to be treated from which the PAC has been removed in the first filtration unit 20 is supplied to the low-pressure reverse osmosis unit 40 to perform a low-pressure reverse osmosis step. In the low-pressure reverse osmosis section 40, 90% of reclaimed water is recovered from the water to be treated by a low-pressure RO membrane on which a predetermined pressure depending on TDS, for example, a pressure of 4.0 MPa is applied, while 10% concentrated water is produced. It is discharged. Here, since silica is removed in the first coagulation-precipitation section 10, the recovery rate of reclaimed water by the low-pressure reverse osmosis section 40 can be improved to 90%.
　第７実施例においては、低圧逆浸透部４０から（１０００Ｌ／ｈ×９０％＝）９００Ｌ／ｈの流量で透過水が排出されて再生水として回収される。透過水の各成分は以下のようになる。
　ＴＤＳ：４０ｍｇ／Ｌ、Ｃａ：１ｍｇ／Ｌ未満、ＳｉＯ2：１ｍｇ／Ｌ
　すなわち、低圧逆浸透部４０によって、ＴＤＳが（４０／４００５≒）０．０１倍、Ｃａが（１／５０＝）０．０２倍、ＳｉＯ2が（１／１０≒）０．１倍まで低減される。 In the seventh embodiment, the permeated water is discharged from the low-pressure reverse osmosis unit 40 at a flow rate of (1000 L / h × 90% =) 900 L / h and recovered as reclaimed water. Each component of permeated water is as follows.
TDS: 40 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
That is, the low-pressure reverse osmosis unit 40 reduces TDS to (40/4005 ≈) 0.01 times, Ca to (1/50 =) 0.02 times, and SiO 2 to (1/10 ≈) 0.1 times. Will be done.
　また、低圧逆浸透部４０から（１０００Ｌ／ｈ×１０％＝）１００Ｌ／ｈの流量で濃縮水が排出される。濃縮水の各成分は以下のようになる。
　ＴＤＳ：４００５０ｍｇ／Ｌ、Ｃａ：５００ｍｇ／Ｌ、ＳｉＯ2：１００ｍｇ／Ｌ
　すなわち、被処理水は低圧逆浸透部４０において、ＴＤＳが（４００５０／４００５＝）１０倍、Ｃａが（５００／５０＝）１０倍、ＳｉＯ2が（１００／１０＝）１０倍に濃縮される。 Further, concentrated water is discharged from the low-pressure reverse osmosis unit 40 at a flow rate of 100 L / h (1000 L / h × 10% =). Each component of concentrated water is as follows.
TDS: 40050 mg / L, Ca: 500 mg / L, SiO 2 : 100 mg / L
That is, the water to be treated is concentrated with TDS (40050/4005 =) 10 times, Ca (500/50 =) 10 times, and SiO 2 (100/10 =) 10 times in the low-pressure reverse osmosis unit 40. ..
　（第２凝集沈殿工程）
　低圧逆浸透部４０において濃縮された濃縮水は、第２凝集沈殿部５０に供給されて第２凝集沈殿工程が行われる。なお、第７実施例においては、被処理水にＣａが残存していることから、第２凝集沈殿部５０の濃縮水には、ｐＨ調整剤および凝集剤が添加される。添加されるｐＨ調整剤は第１凝集沈殿部１０に添加されたｐＨ調整剤と同様に、例えばＮａＯＨまたはＣａ（ＯＨ）2であるが、必ずしも限定されない。添加される凝集剤は、Ｃａおよびシリカを凝集させるために、例えばＮａ2ＣＯ3およびＰＡＣである。Ｎａ2ＣＯ3の濃度はＣａに対して当量とし、ＰＡＣの濃度はＳｉＯ2に対して２倍当量とすることが好ましいが、必ずしも限定されない。第２凝集沈殿部５０においては、この状態で３０分程度静置される。第２凝集沈殿部５０においては、被処理水からスケール成分として、ＣａＣＯ3およびシリカの一部が凝集されて除去される。 (Second coagulation sedimentation step)
The concentrated water concentrated in the low-pressure reverse osmosis section 40 is supplied to the second coagulation sedimentation section 50 to perform the second coagulation sedimentation step. In the seventh embodiment, since Ca remains in the water to be treated, a pH adjuster and a coagulant are added to the concentrated water of the second coagulation sedimentation section 50. The pH adjuster added is, for example, NaOH or Ca (OH) 2 , like the pH adjuster added to the first coagulation sedimentation section 10, but is not necessarily limited. The coagulants added are, for example, Na 2 CO 3 and PAC for aggregating Ca and silica. It is preferable that the concentration of Na 2 CO 3 is equivalent to Ca and the concentration of PAC is twice equivalent to SiO 2 , but it is not always limited. In the second coagulation sedimentation portion 50, it is allowed to stand in this state for about 30 minutes. In the second coagulation sedimentation section 50, CaCO 3 and a part of silica are coagulated and removed from the water to be treated as scale components.
　（第２ろ過工程）
　第２凝集沈殿部５０においてスケール成分としてＣａＣＯ3およびシリカが凝集沈殿されて得られた濃縮水は、第２ろ過部６０に供給されて、第２ろ過工程が行われる。第２ろ過部６０においては、Ｈ2ＳＯ4またはＨＣｌなどの酸が添加されて、ｐＨが５～６．５程度に調整される。第２ろ過部６０においては、濃縮水が３０分間以上静置されて、未反応のＰＡＣが除去される。
　第２ろ過部６０から排出される濃縮水の各成分は以下のようになる。
　ＴＤＳ：４００００ｍｇ／Ｌ、Ｃａ：５０ｍｇ／Ｌ、ＳｉＯ2：１０ｍｇ／Ｌ
　すなわち、第２凝集沈殿部５０および第２ろ過部６０によって、Ｃａが（５００－５０＝）４５０ｍｇ／Ｌ、ＳｉＯ2が（１００－１０＝）９０ｍｇ／Ｌ除去される。 (Second filtration step)
The concentrated water obtained by coagulating and precipitating CaCO 3 and silica as scale components in the second coagulation sedimentation section 50 is supplied to the second filtration section 60, and the second filtration step is performed. In the second filtration unit 60, an acid such as H 2 SO 4 or HCl is added to adjust the pH to about 5 to 6.5. In the second filtration unit 60, the concentrated water is allowed to stand for 30 minutes or more to remove unreacted PAC.
Each component of the concentrated water discharged from the second filtration unit 60 is as follows.
TDS: 40,000 mg / L, Ca: 50 mg / L, SiO 2 : 10 mg / L
That is, Ca is removed (500-50 =) 450 mg / L and SiO 2 is removed (100-10 =) 90 mg / L by the second coagulation sedimentation section 50 and the second filtration section 60.
　（カルシウム除去工程）
　第２ろ過部６０においてＰＡＣが除去された被処理水は、軟水器３０に供給されてカルシウム除去工程が行われる。軟水器３０においては、例えば、カチオン交換樹脂などによって被処理水からＣａが除去される。軟水器３０から排出される被処理水の各成分は以下のようになる。
　ＴＤＳ：４０３５０ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：１０ｍｇ／Ｌ
　すなわち、軟水器３０において、Ｃａが（５０－０＝）５０ｍｇ／Ｌ（全量）除去される。 (Calcium removal process)
The water to be treated from which the PAC has been removed in the second filtration unit 60 is supplied to the water softener 30 to perform a calcium removal step. In the water softener 30, Ca is removed from the water to be treated by, for example, a cation exchange resin. Each component of the water to be treated discharged from the water softener 30 is as follows.
TDS: 40350 mg / L, Ca: 0 mg / L, SiO 2 : 10 mg / L
That is, in the water softener 30, Ca is removed (50-0 =) 50 mg / L (total amount).
　（正浸透処理工程）
　次に、軟水器３０から排出された濃縮水は、正浸透装置７０に供給されて正浸透処理工程が行われる。正浸透処理工程においては、濃縮水から再生水が得られるとともに、さらに濃縮された高濃縮水が排出される。 (Forward osmosis treatment process)
Next, the concentrated water discharged from the water softener 30 is supplied to the forward osmosis device 70 to perform a forward osmosis treatment step. In the forward osmosis treatment step, reclaimed water is obtained from the concentrated water, and further concentrated highly concentrated water is discharged.
　具体的に、正浸透装置７０においては、ＦＯ膜によって濃縮水から（２／３≒）６７％の再生水が回収される一方、（１／３≒）３３％の高濃縮水が排出される。第７実施例においては、正浸透装置７０から（１００Ｌ／ｈ×６７％＝）６７Ｌ／ｈの流量で透過水が排出されて再生水として回収される。一方、正浸透装置７０から（１００Ｌ／ｈ×３３％＝）３３Ｌ／ｈの流量で高濃縮水が排出される。高濃縮水の各成分は以下のようになる。
　ＴＤＳ：１２１０５０ｍｇ／Ｌ、Ｃａ：０ｍｇ／Ｌ、ＳｉＯ2：３０ｍｇ／Ｌ Specifically, in the forward osmosis apparatus 70, (2/3 ≈) 67% of reclaimed water is recovered from the concentrated water by the FO membrane, while (1/3 ≈) 33% of highly concentrated water is discharged. In the seventh embodiment, the permeated water is discharged from the forward osmosis device 70 at a flow rate of (100 L / h × 67% =) 67 L / h and recovered as reclaimed water. On the other hand, highly concentrated water is discharged from the forward osmosis device 70 at a flow rate of (100 L / h × 33% =) 33 L / h. Each component of highly concentrated water is as follows.
TDS: 211050 mg / L, Ca: 0 mg / L, SiO 2 : 30 mg / L
　すなわち、濃縮水は、正浸透装置７０において、ＴＤＳが（１２１０５／４００００≒）約３倍、ＳｉＯ2が（３０／１０＝）３倍に濃縮される。また、第７実施例において、流量が１０００Ｌ／ｈの被処理水からは、流量が３３Ｌ／ｈの高濃縮水が排出できることになる。これにより、第７実施例において採用した水処理装置７によれば、第１実施例と同様に、従来技術に比して被処理水をさらに７．６倍程度濃縮して排出でき、再生水の回収率を大幅に向上できる。 That is, in the concentrated water, TDS is concentrated (12105/40000≈) about 3 times and SiO 2 is concentrated (30/10 =) 3 times in the forward osmosis apparatus 70. Further, in the seventh embodiment, highly concentrated water having a flow rate of 33 L / h can be discharged from the water to be treated having a flow rate of 1000 L / h. As a result, according to the water treatment apparatus 7 adopted in the seventh embodiment, the water to be treated can be further concentrated and discharged by about 7.6 times as compared with the prior art as in the first embodiment, and the reclaimed water can be discharged. The recovery rate can be significantly improved.
　（蒸留晶析工程）
　正浸透処理工程後の蒸留晶析工程は、第１実施例と同様である。すなわち、第７実施例においては、流量が３３Ｌ／ｈの高濃縮水から、４Ｌ／ｈ分の固形成分が除去されて、流量が２９Ｌ／ｈの精製水が再生水として回収される。 (Distillation crystallization step)
The distillation crystallization step after the forward osmosis treatment step is the same as in the first embodiment. That is, in the seventh embodiment, 4 L / h of solid components are removed from the highly concentrated water having a flow rate of 33 L / h, and purified water having a flow rate of 29 L / h is recovered as reclaimed water.
　以上の低圧逆浸透部４０から得られる透過水に、正浸透装置７０から得られる透過水および蒸留晶析部８０から得られる精製水が供給されて回収される。これにより、第７実施例においては、第４の実施形態による水処理装置７によって、流量が１０００Ｌ／ｈの被処理水から、流量が（９００＋６７＋２９＝）９９６Ｌ／ｈの再生水が回収されるとともに、４Ｌ／ｈ分の固形成分が除去される。再生水の各成分は以下のようになる。
　ＴＤＳ：３６ｍｇ／Ｌ、Ｃａ：１ｍｇ／Ｌ未満、ＳｉＯ2：１ｍｇ／Ｌ The permeated water obtained from the above low-pressure reverse osmosis unit 40 is supplied with the permeated water obtained from the forward osmosis device 70 and the purified water obtained from the distillation crystallization unit 80 and recovered. As a result, in the seventh embodiment, the water treatment apparatus 7 according to the fourth embodiment recovers the reclaimed water having a flow rate of (900 + 67 + 29 =) 996 L / h from the water to be treated having a flow rate of 1000 L / h. 4 L / h of solid components are removed. Each component of reclaimed water is as follows.
TDS: 36 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
　（第４変形例）
　次に、上述した第４の実施形態による水処理装置の第４変形例について説明する。図９は、第４変形例による水処理装置を模式的に示すブロック図である。図９に示すように、第４変形例による水処理装置８は、第４の実施形態による水処理装置７の正浸透装置７０の代わりに第１変形例と同様の高圧逆浸透部９０が設けられる。 (Fourth modification)
Next, a fourth modification of the water treatment apparatus according to the fourth embodiment described above will be described. FIG. 9 is a block diagram schematically showing a water treatment apparatus according to a fourth modification. As shown in FIG. 9, the water treatment device 8 according to the fourth modification is provided with a high-pressure reverse osmosis unit 90 similar to the first modification instead of the forward osmosis device 70 of the water treatment device 7 according to the fourth embodiment. Be done.
　高圧逆浸透部９０においては、濃縮水から不純物濃度が低下された透過水を排出するとともに、濃縮水がさらに濃縮された高濃縮水を排出する。排出された透過水は再生水として、低圧逆浸透部４０から排出される透過水に合流される。一方、排出された高濃縮水は、蒸留晶析部８０に供給される。その他の構成は、第４の実施形態と同様である。第４変形例においては、軟水器３０を高圧逆浸透部９０の前段に設けていることにより、高圧逆浸透部９０をアルカリ性の条件下で運転する場合に、Ｍｇ（ＯＨ）2のスケールリスクを低減することができる。 In the high-pressure reverse osmosis section 90, the permeated water having a reduced impurity concentration is discharged from the concentrated water, and the highly concentrated water in which the concentrated water is further concentrated is discharged. The discharged permeated water is merged with the permeated water discharged from the low-pressure reverse osmosis unit 40 as reclaimed water. On the other hand, the discharged highly concentrated water is supplied to the distillation crystallization unit 80. Other configurations are the same as those in the fourth embodiment. In the fourth modification, the water softener 30 is provided in front of the high-pressure reverse osmosis section 90, so that the scale risk of Mg (OH) 2 is increased when the high-pressure reverse osmosis section 90 is operated under alkaline conditions. Can be reduced.
　（水処理方法）
　（第８実施例）
　次に、以上のように構成された第４変形例による水処理装置８を用いた水処理方法の第８実施例について説明する。なお、第８実施例における被処理水は、第１～第７実施例における被処理水と同様である。まず、第８実施例による水処理方法においては、第１凝集沈殿工程、第１ろ過工程、低圧逆浸透工程、第２凝集沈殿工程、第２ろ過工程、およびカルシウム除去工程については、第７実施例と同様である。 (Water treatment method)
(8th Example)
Next, an eighth embodiment of the water treatment method using the water treatment apparatus 8 according to the fourth modification configured as described above will be described. The water to be treated in the 8th example is the same as the water to be treated in the 1st to 7th examples. First, in the water treatment method according to the eighth embodiment, the first coagulation sedimentation step, the first filtration step, the low pressure reverse osmosis step, the second coagulation sedimentation step, the second filtration step, and the calcium removal step are carried out in the seventh step. Similar to the example.
　（高圧逆浸透工程）
　次に、カルシウム除去工程に続いて、軟水器３０から排出された濃縮水は、高圧逆浸透部９０に供給されて高圧逆浸透工程が行われる。高圧逆浸透部９０においては、濃縮水から透過水が得られるとともにさらに濃縮された高濃縮水が排出される。 (High pressure reverse osmosis process)
Next, following the calcium removal step, the concentrated water discharged from the water softener 30 is supplied to the high-pressure reverse osmosis unit 90, and the high-pressure reverse osmosis step is performed. In the high-pressure reverse osmosis section 90, permeated water is obtained from the concentrated water, and more concentrated highly concentrated water is discharged.
　具体的に、高圧逆浸透部９０においては、高圧ＲＯ膜によって濃縮水から（１／２＝）５０％の透過水が再生水として回収される一方、（１／２＝）５０％の高濃縮水が排出される。第８実施例においては、高圧逆浸透部９０から（１００Ｌ／ｈ×５０％＝）５０Ｌ／ｈの流量で透過水が排出されて再生水として回収され、（１００Ｌ／ｈ×５０％＝）５０Ｌ／ｈの流量で高濃縮水が排出される。高濃縮水の各成分は以下のようになる。
　ＴＤＳ：８０７００ｍｇ／Ｌ、Ｃａ：１００ｍｇ／Ｌ、ＳｉＯ2：２０ｍｇ／Ｌ Specifically, in the high-pressure reverse osmosis section 90, (1/2 =) 50% of permeated water is recovered as reclaimed water from the concentrated water by the high-pressure RO membrane, while (1/2 =) 50% of highly concentrated water is recovered. Is discharged. In the eighth embodiment, the permeated water is discharged from the high-pressure reverse osmosis unit 90 at a flow rate of (100 L / h × 50% =) 50 L / h and recovered as reclaimed water, and (100 L / h × 50% =) 50 L /. Highly concentrated water is discharged at the flow rate of h. Each component of highly concentrated water is as follows.
TDS: 80700 mg / L, Ca: 100 mg / L, SiO 2 : 20 mg / L
　すなわち、濃縮水は、高圧逆浸透部９０によって、ＴＤＳが（８０７００／４０３５０＝）２倍、ＳｉＯ2が（２０／１０＝）２倍に濃縮される。これにより、第８実施例において、流量が１０００Ｌ／ｈの被処理水から、流量が５０Ｌ／ｈの高濃縮水が排出されることになり、第８実施例で採用された水処理装置８によれば、従来に比して被処理水をさらに５倍程度濃縮して排出でき、再生水の生成効率を大幅に向上できる。 That is, in the concentrated water, TDS is concentrated (80700/40350 =) twice and SiO 2 is concentrated (20/10 =) twice by the high-pressure reverse osmosis unit 90. As a result, in the eighth embodiment, the highly concentrated water having a flow rate of 50 L / h is discharged from the water to be treated having a flow rate of 1000 L / h, and the water treatment apparatus 8 adopted in the eighth embodiment has a flow rate of 50 L / h. According to this, the water to be treated can be further concentrated and discharged about 5 times as compared with the conventional case, and the production efficiency of reclaimed water can be significantly improved.
　（蒸留晶析工程）
　高圧逆浸透部９０において濃縮された高濃縮水は、蒸留晶析部８０に供給されて蒸留晶析工程が行われる。蒸留晶析部８０においては、高濃縮水に対して、例えば１２０℃程度の温度で精製処理が行われ、精製された精製水は再生水として回収される。精製水から分離された固形成分としての塩は、外部に廃棄される。第２実施例においては、流量が５０Ｌ／ｈの高濃縮水から、４Ｌ／ｈ分の固形成分が除去されて、流量が４６Ｌ／ｈの精製水が再生水として回収される。 (Distillation crystallization step)
The highly concentrated water concentrated in the high-pressure reverse osmosis unit 90 is supplied to the distillation crystallization unit 80 to perform the distillation crystallization step. In the distillation crystallization unit 80, highly concentrated water is purified at a temperature of, for example, about 120 ° C., and the purified purified water is recovered as reclaimed water. The salt as a solid component separated from purified water is discarded to the outside. In the second embodiment, 4 L / h of solid components are removed from the highly concentrated water having a flow rate of 50 L / h, and purified water having a flow rate of 46 L / h is recovered as reclaimed water.
　以上の低圧逆浸透部４０から得られる透過水に、高圧逆浸透部９０から得られる透過水および蒸留晶析部８０から得られる精製水が供給されて回収される。これにより、第８実施例においては、第２変形例による水処理装置４によって、流量が１０００Ｌ／ｈの被処理水から、流量が（９００＋５０＋４６＝）９９６Ｌ／ｈの再生水が回収されるとともに、４Ｌ／ｈ分の固形成分が除去される。再生水の各成分は第４の実施形態と同様に、以下のようになる。
　ＴＤＳ：３６ｍｇ／Ｌ、Ｃａ：１ｍｇ／Ｌ未満、ＳｉＯ2：１ｍｇ／Ｌ The permeated water obtained from the high-pressure reverse osmosis unit 40 and the purified water obtained from the distillation crystallization unit 80 are supplied to the permeated water obtained from the above low-pressure reverse osmosis unit 40 and recovered. As a result, in the eighth embodiment, the water treatment apparatus 4 according to the second modification recovers the reclaimed water having a flow rate of (900 + 50 + 46 =) 996 L / h from the water to be treated having a flow rate of 1000 L / h, and 4 L. The solid component of / h is removed. Each component of the reclaimed water is as follows, as in the fourth embodiment.
TDS: 36 mg / L, Ca: less than 1 mg / L, SiO 2 : 1 mg / L
　以上説明した第４の実施形態によれば、低圧逆浸透部４０の前段の第１凝集沈殿部１０において、Ｃａに加えてシリカを除去し、低圧逆浸透部４０と正浸透装置７０や高圧逆浸透部９０との間に第２凝集沈殿部５０を設け、被処理水が濃縮された濃縮水からシリカを除去していることにより、第１～第３の実施形態と同様の効果を得ることができる。さらに、正浸透装置７０や高圧逆浸透部９０の前段に軟水器３０を設けていることにより、ＦＯ膜やＲＯ膜に生じやすいＣａのスケーリングを抑制できるので、水処理装置７，８による被処理水の濃縮率を、従来の水処理装置に比して向上できる。 According to the fourth embodiment described above, silica is removed in addition to Ca in the first coagulation sedimentation section 10 in the previous stage of the low pressure reverse osmosis section 40, and the low pressure reverse osmosis section 40, the forward osmosis device 70, and the high pressure reverse osmosis section 40 are removed. By providing the second coagulation sedimentation portion 50 between the permeation portion 90 and removing silica from the concentrated water in which the water to be treated is concentrated, the same effect as that of the first to third embodiments can be obtained. Can be done. Further, by providing the water softener 30 in front of the forward osmosis device 70 and the high-pressure reverse osmosis unit 90, it is possible to suppress the scaling of Ca that tends to occur in the FO film and the RO film, so that the water treatment devices 7 and 8 are to be treated. The concentration rate of water can be improved as compared with the conventional water treatment apparatus.
　（凝集沈殿部およびろ過部）
　次に、第１～第４の実施形態による水処理装置１～８に採用される凝集沈殿部およびろ過部の構成について説明する。なお、凝集沈殿部およびろ過部は、第１凝集沈殿部１０および第１ろ過部２０と、第２凝集沈殿部５０および第２ろ過部６０との少なくとも一方を示す。 (Coagulation sedimentation section and filtration section)
Next, the configurations of the coagulation sedimentation section and the filtration section adopted in the water treatment devices 1 to 8 according to the first to fourth embodiments will be described. The coagulation sedimentation section and the filtration section indicate at least one of the first coagulation sedimentation section 10 and the first filtration section 20 and the second coagulation sedimentation section 50 and the second filtration section 60.
　従来、特にシリカの原因物質であるケイ酸イオン（ＳｉＯ4 4-）は水中において種々の形態をとることが知られており、塩を含有する水からの除去が極めて困難なスケーリングの原因物質の１つである。ケイ酸イオン（ＳｉＯ4 4-）を除去するためには、主として樹脂や吸着剤を利用した除去方法と、薬剤投与による共沈または凝集沈殿による除去方法との２つの方法が検討されている。 Conventionally, it is known that silicate ion (SiO 4 4- ), which is a causative substance of silica, takes various forms in water, and is a causative substance of scaling which is extremely difficult to remove from water containing a salt. There is one. In order to remove silicate ions (SiO 4 4- ), two methods have been studied, one is a removal method mainly using a resin or an adsorbent, and the other is a removal method by coprecipitation or coagulation precipitation by administration of a drug.
　これらのうちの樹脂や吸着剤を利用したシリカの除去方法として、純水製造プロセスにおいてはイオン交換樹脂を利用したシリカの除去方法が知られている。ところが、高濃度のシリカ含有排水や、シリカ以外の陰イオンが多く存在する陰イオンリッチな高塩濃度の排水においては、イオン交換樹脂の再生頻度が増加することになるため、水処理が高コスト化するため好ましくない。また、イオン交換樹脂の交換容量の近傍においては、吸着していたシリカが溶出して、シリカ濃度が急激に上昇するという問題も生じる。この場合、不可逆的なシリカによるスケールが突然発生することになるため、半透膜を用いた水処理プロセスにおいて大きな問題になる。そこで、凝集剤を投与することによってシリカを除去する方法を採用すると、凝集剤の高コスト化が問題になることから、被処理水を処理する際の凝集剤の使用量の低減が求められていた。 Among these, as a method for removing silica using a resin or an adsorbent, a method for removing silica using an ion exchange resin is known in the pure water production process. However, in high-concentration silica-containing wastewater and wastewater with high salt concentration rich in anions in which many anions other than silica are present, the frequency of regeneration of the ion exchange resin increases, so that water treatment is expensive. It is not preferable because it becomes Further, in the vicinity of the exchange capacity of the ion exchange resin, there is a problem that the adsorbed silica is eluted and the silica concentration rapidly increases. In this case, irreversible silica scale is suddenly generated, which poses a big problem in the water treatment process using a semipermeable membrane. Therefore, if a method of removing silica by administering a coagulant is adopted, the cost of the coagulant becomes high. Therefore, it is required to reduce the amount of the coagulant used when treating the water to be treated. rice field.
　上述した問題を解決するために、以下に説明する凝集沈殿部およびろ過部（以下、まとめて凝集沈殿部と称する）の第１構成例、第２構成例、第３構成例、および第４構成例は、被処理水を処理する際に、添加する凝集剤の使用量を低減できる凝集沈殿部である。 In order to solve the above-mentioned problems, the first configuration example, the second configuration example, the third configuration example, and the fourth configuration of the coagulation sedimentation section and the filtration section (hereinafter collectively referred to as the coagulation sedimentation section) described below. An example is a coagulation sedimentation portion that can reduce the amount of coagulant to be added when treating water to be treated.
　（凝集沈殿部）
　（第１構成例）
　まず、本発明の実施形態による水処理装置１～８の凝集沈殿部の第１構成例について説明する。図１０は、第１構成例による凝集沈殿部を模式的に示すブロック図である。図１０に示すように、第１構成例による凝集沈殿部１０Ａ，５０Ａは、受入槽１１、反応槽１２、ｐＨ調整槽１３、ポンプ１４、脱水機１５、シリカ濃度計１６，１７、およびろ過部２０，６０を備える。 (Coagulation sedimentation part)
(First configuration example)
First, a first configuration example of the coagulation-precipitation portion of the water treatment devices 1 to 8 according to the embodiment of the present invention will be described. FIG. 10 is a block diagram schematically showing a coagulation sedimentation portion according to the first configuration example. As shown in FIG. 10, the coagulation sedimentation portions 10A and 50A according to the first configuration example include a receiving tank 11, a reaction tank 12, a pH adjusting tank 13, a pump 14, a dehydrator 15, silica densitometers 16 and 17, and a filtration unit. 20 and 60 are provided.
　受入槽１１は、例えば冷却塔（図示せず）などから排出される排水などの被処理水が流入される槽である。受入槽１１におけるシリカ濃度（ＳｉＯ2濃度）はシリカ濃度計５１により計測される。シリカを含む被処理水は、受入槽１１に貯留された後に反応槽１２に供給される。反応槽１２には、シリカを凝集沈殿させる例えばＰＡＣ、およびＣａを凝集沈殿させる例えばＮａ2ＣＯ3などの凝集剤が添加される。これとともに反応槽１２においては、ｐＨが８以上１２以下の例えば１０．５程度に調整されて、被処理水からＣａやシリカなどのスケール成分が除去される。なお、反応槽１２は、並列して被処理水を流入可能な２槽や３槽などの複数の槽から構成して、処理水の流れを複数系列として構成することが可能である。 The receiving tank 11 is a tank into which water to be treated, such as wastewater discharged from a cooling tower (not shown), flows into the receiving tank 11. The silica concentration (SiO 2 concentration) in the receiving tank 11 is measured by the silica densitometer 51. The water to be treated containing silica is stored in the receiving tank 11 and then supplied to the reaction tank 12. A flocculant such as PAC that coagulates and precipitates silica and Na 2 CO 3 that coagulates and precipitates Ca is added to the reaction vessel 12. At the same time, in the reaction vessel 12, the pH is adjusted to 8 or more and 12 or less, for example, about 10.5, and scale components such as Ca and silica are removed from the water to be treated. The reaction tank 12 can be composed of a plurality of tanks such as two tanks and three tanks capable of inflowing the water to be treated in parallel, and the flow of the treated water can be configured as a plurality of series.
　反応槽１２において得られた上澄み水は、ｐＨ調整槽１３に供給されてｐＨが４以上８以下の例えば６．５程度に調整される。これにより、上澄み水のＡｌが不溶性になる。ｐＨ調整槽１３におけるシリカ濃度は、シリカ濃度計５２により計測される。ｐＨ調整槽１３においてｐＨが調整された調整水であるＡｌ含有水は、ろ過部２０，６０に供給される。ろ過部２０，６０は砂ろ過または所定の膜を有して構成される。ろ過部２０，６０においては、調整水からＡｌを除去するろ過処理が行われ、処理水が得られる。 The supernatant water obtained in the reaction tank 12 is supplied to the pH adjusting tank 13 and adjusted to a pH of 4 or more and 8 or less, for example, about 6.5. This makes Al in the supernatant water insoluble. The silica concentration in the pH adjusting tank 13 is measured by the silica densitometer 52. The Al-containing water, which is the pH-adjusted water in the pH-adjusting tank 13, is supplied to the filtration units 20 and 60. The filtration units 20 and 60 are configured to have sand filtration or a predetermined film. In the filtration units 20 and 60, a filtration treatment for removing Al from the adjusted water is performed to obtain treated water.
　上述したように凝集沈殿部１０Ａ，５０Ａにおける反応槽１２においては、Ｃａおよびシリカを含むスケール成分が除去される。すなわち、例えば冷却塔などから排出された被処理水はＣａおよびシリカを含む被処理水として受入槽１１に一時的に貯留された後、反応槽１２に供給される。反応槽１２の初期状態としては、すでに複数回の凝集沈殿処理が行われた後における、凝集汚泥としてのスラッジＳの一部が残留した状態とする。反応槽１２のｐＨは、塩基性を示すｐＨに調整される。 As described above, in the reaction vessel 12 in the coagulation sedimentation portions 10A and 50A, scale components including Ca and silica are removed. That is, for example, the water to be treated discharged from the cooling tower or the like is temporarily stored in the receiving tank 11 as the water to be treated containing Ca and silica, and then supplied to the reaction tank 12. The initial state of the reaction vessel 12 is a state in which a part of sludge S as coagulated sludge remains after the coagulation and precipitation treatment has already been performed a plurality of times. The pH of the reaction vessel 12 is adjusted to a pH showing basicity.
　次に、反応槽１２において、例えばスケール成分を除去するために、ＰＡＣや例えばＮａ2ＣＯ3などの薬剤を注入しながら、攪拌部（図示せず）によって撹拌が実行される。第１構成例においては、攪拌されたスラッジＳが凝集剤として機能して、被処理水に含有されたシリカと混合して、シリカの一部が沈殿する。なお、スケール成分としては、主としてＳｉＯ2を含むシリカ、および例えばＣａＣＯ3、ＣａＳＯ4、およびＣａＦ2などのＣａの化合物が含まれる。 Next, in the reaction vessel 12, stirring is performed by a stirring unit (not shown) while injecting a chemical such as PAC or Na 2 CO 3 in order to remove the scale component, for example. In the first configuration example, the agitated sludge S functions as a coagulant and mixes with the silica contained in the water to be treated, and a part of the silica precipitates. The scale component mainly includes silica containing SiO 2 and a compound of Ca such as CaCO 3 , CaSO 4 , and CaF 2 .
　スラッジが沈降した反応槽１２から、ポンプ１４によってスラッジＳの一部を排出させて、脱水機１５に供給する。スラッジＳの排出量としては、初期状態におけるスラッジＳの量に対して、増加したスラッジＳの増加量分とすることが好ましい。排出されたスラッジＳは、脱水機１５によって脱水されて脱水ケーキとなって、廃棄または所定の用途に再利用される。 A part of the sludge S is discharged from the reaction tank 12 in which the sludge has settled by the pump 14 and supplied to the dehydrator 15. The amount of sludge S discharged is preferably the amount of increase in sludge S with respect to the amount of sludge S in the initial state. The discharged sludge S is dehydrated by the dehydrator 15 to become a dehydrated cake, which is discarded or reused for a predetermined purpose.
　次に、反応槽１２において、ｐＨ調整手段としての薬剤注入装置（図示せず）によってｐＨ調整剤を添加する一方、攪拌手段としての攪拌部（図示せず）によって攪拌を行う。これにより、スラッジＳが再度攪拌されて懸濁状態となる。第１構成例においては、懸濁状態となったスラッジＳが凝集剤として機能して、被処理水からシリカの一部がスラッジＳに吸着され、沈殿することによって除去される。なお、上述した反応槽１２において計測されたシリカ濃度に応じて、ＰＡＣをさらに添加しても良い。スラッジＳが沈殿した後、上澄み水は、後段のｐＨ調整槽１３に供給される。また、水処理は、流入・薬剤注入に復帰する。 Next, in the reaction tank 12, the pH adjuster is added by a drug injection device (not shown) as a pH adjusting means, while stirring is performed by a stirring unit (not shown) as a stirring means. As a result, the sludge S is stirred again and becomes a suspension state. In the first configuration example, the suspended sludge S functions as a coagulant, and a part of silica is adsorbed by the sludge S from the water to be treated and is removed by precipitation. In addition, PAC may be further added according to the silica concentration measured in the above-mentioned reaction tank 12. After the sludge S has settled, the supernatant water is supplied to the pH adjusting tank 13 in the subsequent stage. In addition, water treatment returns to inflow and drug injection.
　（凝集沈殿汚泥）
　次に、凝集剤として機能する凝集沈殿汚泥であるスラッジＳについて説明する。まず、反応槽１２に流入される例えば冷却塔からの排水などの被処理水に含まれるシリカについて、本発明者が行った鋭意検討について説明する。 (Coagulation sediment sludge)
Next, sludge S, which is a coagulated sediment sludge that functions as a coagulant, will be described. First, the diligent study conducted by the present inventor on silica contained in the water to be treated, such as wastewater from a cooling tower, which flows into the reaction vessel 12, will be described.
　すなわち、本発明者の知見によれば、シリカは、排水中で溶解性シリカと非溶解性のコロイド状シリカに分類される。本発明者の実験および実験に伴う鋭意検討によれば、溶解性シリカおよびコロイド状シリカに対して、アルミニウム塩の投与によって発生する凝集汚泥フロックは、次のような効果を示すと考えられる。 That is, according to the findings of the present inventor, silica is classified into soluble silica and insoluble colloidal silica in wastewater. According to the experiments of the present invention and the diligent studies accompanying the experiments, it is considered that the aggregated sludge flocs generated by the administration of the aluminum salt have the following effects on the soluble silica and the colloidal silica.
　まず、主としてケイ酸イオンを含む溶解性シリカは、ｐＨが８以上１２以下の塩基性条件下において負の電荷を帯びている。一般に、塩基性条件下における溶解性シリカは、重合して不溶性のシリカとなる反応速度が速いことが知られている。一方、アルミニウム塩を含んだ凝集汚泥フロックは、アルミニウムイオンに由来する正の電荷を帯びた部位が局在している。そこで、本発明者が、凝集沈殿汚泥を再使用する実験を行ったところ、凝集汚泥フロックは、アルミニウムイオンの価数およびモル数から導出されるイオン強度よりも、多くの溶解性シリカを捕捉していることが判明した。 First, soluble silica, which mainly contains silicate ions, is negatively charged under basic conditions with a pH of 8 or more and 12 or less. In general, it is known that soluble silica under basic conditions has a high reaction rate of polymerizing to insoluble silica. On the other hand, in the aggregated sludge floc containing an aluminum salt, a positively charged portion derived from an aluminum ion is localized. Therefore, when the present inventor conducted an experiment to reuse the coagulated sediment sludge, the coagulated sludge floc captured more soluble silica than the ionic strength derived from the valence and the number of moles of aluminum ions. It turned out that.
　そこで、溶解性シリカの凝集汚泥フロックに対する反応機構は、次の通りに考えられる。すなわち、負に帯電した溶解性シリカは、凝集汚泥フロック中におけるアルミニウムイオンのような正に帯電した部分（吸着活性点）に静電気的に引き寄せられて吸着する。塩基性条件下においては、ケイ酸イオンの重合速度が大きいことから、溶解性シリカは、ケイ酸イオンが吸着したサイトの近傍に接近した他の溶解性シリカと重合して凝集汚泥フロックに吸着される。このため、吸着可能なシリカの量は、アルミニウムの価数から導き出される量より大きくなる。攪拌を行うことにより、溶解性シリカと凝集汚泥フロック中の吸着活性点との接触確率が増加することから、シリカの除去率が向上する。さらに、スラッジＳの使用回数、すなわちサイクル回数を多くすることによって、未活用の吸着活性点を低減することが可能となる。 Therefore, the reaction mechanism of soluble silica to aggregated sludge flocs is considered as follows. That is, the negatively charged soluble silica is electrostatically attracted to and adsorbed to a positively charged portion (adsorption active point) such as aluminum ions in the aggregated sludge flocs. Under basic conditions, the rate of polymerization of silicate ions is high, so soluble silica is adsorbed on aggregated sludge flocs by polymerizing with other soluble silicas that are close to the site where silicate ions are adsorbed. To. Therefore, the amount of silica that can be adsorbed is larger than the amount derived from the valence of aluminum. Stirring increases the probability of contact between the soluble silica and the adsorption active points in the aggregated sludge flocs, thus improving the silica removal rate. Further, by increasing the number of times the sludge S is used, that is, the number of cycles, it is possible to reduce the unused adsorption active sites.
　また、コロイド状シリカは、溶解性シリカが互いに重合して数１０ｎｍ～数ｌ００ｎｍの大きさになったものである。コロイド状の場合、粒子径が小さいため沈降性が極めて低い。また、塩基性条件下におけるコロイド状シリカは、一部が溶解して溶解性シリカと同様の形態になり、上述した反応機構と同様の反応が生じる。溶解しなかったコロイド状シリカにおいても、表面が負の電荷を帯びていることから、アルミニウムイオンの正の電荷に静電気的に引き寄せられ、凝集および重合して沈降性が向上する。これにより、被処理水からシリカが除去される。 Further, the colloidal silica is obtained by polymerizing soluble silica with each other to have a size of several tens of nm to several 000 nm. In the case of colloid, the sedimentation property is extremely low because the particle size is small. Further, the colloidal silica under basic conditions is partially dissolved to form a form similar to that of soluble silica, and a reaction similar to the reaction mechanism described above occurs. Even in the undissolved colloidal silica, since the surface is negatively charged, it is electrostatically attracted to the positive charge of aluminum ions, and aggregates and polymerizes to improve the sedimentation property. As a result, silica is removed from the water to be treated.
　以上のようにして、被処理水に対してＰＡＣなどの凝集剤を添加することによって得られたスラッジＳは、シリカ除去率は低下するものの、複数回再利用することが可能である。本発明者が反応槽１２におけるｐＨに応じたシリカ除去率について実験を行ったところ、反応槽１２内の被処理水のｐＨを８とした場合には、スラッジＳのサイクル回数に伴って、シリカ除去率が４７％程度から２７％程度まで低減することが判明した。さらに、本発明者が反応槽１２内の被処理水のｐＨを１０．５とした場合には、シリカ除去率がスラッジＳのサイクル回数に伴って、シリカ除去率が９７％程度から７０％程度まで低減することが判明した。すなわち、反応槽１２内の被処理水のｐＨを８とした場合に比して、ｐＨを１０．５としてより塩基性を強くした場合には、シリカ除去率が２～２．６倍程度向上した。そのため、反応槽１２内の被処理水に対するシリカの除去処理を行った場合に、被処理水のｐＨ、およびＰＡＣを添加する場合にはＰＡＣの添加量を設定することによって、所望とするシリカ濃度を得ることが可能になる。 As described above, the sludge S obtained by adding a coagulant such as PAC to the water to be treated can be reused a plurality of times, although the silica removal rate is lowered. When the present inventor conducted an experiment on the silica removal rate according to the pH in the reaction vessel 12, when the pH of the water to be treated in the reaction vessel 12 was 8, the silica was increased with the number of cycles of sludge S. It was found that the removal rate was reduced from about 47% to about 27%. Further, when the present inventor sets the pH of the water to be treated in the reaction vessel 12 to 10.5, the silica removal rate is about 97% to 70% with the number of cycles of sludge S. It turned out to be reduced to. That is, the silica removal rate is improved by about 2 to 2.6 times when the pH is set to 10.5 and the basicity is strengthened as compared with the case where the pH of the water to be treated in the reaction tank 12 is set to 8. did. Therefore, when the silica to be treated is removed from the water to be treated in the reaction vessel 12, the desired silica concentration is set by setting the pH of the water to be treated and the amount of PAC to be added when PAC is added. Will be able to be obtained.
　以上説明したように凝集沈殿部の第１構成例によれば、シリカの除去の際に発生した凝集沈殿汚泥であるスラッジＳを、改めてシリカの吸着核、すなわち凝集剤として使用しているので、シリカの除去に要するＰＡＣなどの薬剤の添加量を低減できる。さらに、スラッジＳを凝集剤として使用していることにより、排出する汚泥の量を低減できるので、排出されたスラッジＳの後処理に要するコストを低減することが可能になる。なお、凝集沈殿汚泥としては、第１凝集沈殿部１０および第２凝集沈殿部５０の少なくとも一方で生成されたスラッジＳを用いることができる。 As described above, according to the first configuration example of the coagulation-sedimentation portion, sludge S, which is coagulation-precipitation sludge generated during the removal of silica, is used again as an adsorption nucleus of silica, that is, as a coagulant. The amount of chemicals such as PAC required for removing silica can be reduced. Further, since the sludge S is used as a coagulant, the amount of sludge discharged can be reduced, so that the cost required for the post-treatment of the discharged sludge S can be reduced. As the coagulation sedimentation sludge, sludge S generated at at least one of the first coagulation sedimentation portion 10 and the second coagulation sedimentation portion 50 can be used.
　（第２構成例）
　次に、凝集沈殿部の第２構成例について説明する。図１１は、第２構成例による凝集沈殿部を示すブロック図である。図１１に示すように、第２構成例による凝集沈殿部１０Ｂ，５０Ｂは、受入槽１１、反応槽１２，ｐＨ調整槽１３、ポンプ１４、脱水機１５、シリカ濃度計１６，１７、汚泥貯留槽１８、およびろ過部２０，６０を備える。受入槽１１、反応槽１２，ｐＨ調整槽１３、ポンプ１４、脱水機１５、シリカ濃度計１６，１７、およびろ過部２０，６０については、第１構成例と同様である。汚泥貯留槽１８は、ポンプ１４を用いて、反応槽１２から排出させたスラッジＳを一時的に貯留した後に反応槽１２に戻すための槽である。 (Second configuration example)
Next, a second configuration example of the coagulation sedimentation portion will be described. FIG. 11 is a block diagram showing a coagulation sedimentation portion according to the second configuration example. As shown in FIG. 11, the coagulation sedimentation portions 10B and 50B according to the second configuration example include a receiving tank 11, a reaction tank 12, a pH adjusting tank 13, a pump 14, a dehydrator 15, silica densitometers 16 and 17, and a sludge storage tank. 18 and filtration units 20 and 60 are provided. The receiving tank 11, the reaction tank 12, the pH adjusting tank 13, the pump 14, the dehydrator 15, the silica densitometers 16 and 17, and the filtration units 20 and 60 are the same as those in the first configuration example. The sludge storage tank 18 is a tank for temporarily storing the sludge S discharged from the reaction tank 12 and then returning it to the reaction tank 12 by using the pump 14.
　凝集沈殿部１０Ｂ，５０Ｂにおける反応槽１２においては、シリカを含むスケール成分が除去される。すなわち、被処理水は、受入槽１１に一時的に貯留された後に、反応槽１２に供給される。反応槽１２の初期状態としては、すでに複数回の凝集沈殿処理が行われた後における、凝集汚泥としてのスラッジＳの一部が残留した状態とする。反応槽１２のｐＨは、塩基性を示すｐＨに調整され、例えば８以上１２以下の１０．５に調整される。 In the reaction vessel 12 in the coagulation sedimentation portions 10B and 50B, the scale component containing silica is removed. That is, the water to be treated is temporarily stored in the receiving tank 11 and then supplied to the reaction tank 12. The initial state of the reaction vessel 12 is a state in which a part of sludge S as coagulated sludge remains after the coagulation and precipitation treatment has already been performed a plurality of times. The pH of the reaction vessel 12 is adjusted to a pH showing basicity, for example, 10.5 of 8 or more and 12 or less.
　次に、反応槽１２において、スケール成分である例えばＣａの化合物などを除去するための例えばＮａ2ＣＯ3などの薬剤を注入しながら、攪拌部（図示せず）によって撹拌が実行される。ここで、第２構成例においては、汚泥貯留槽１８に貯留されたスラッジＳの一部を脱水機１５に供給して脱水を行う一方、スラッジＳの残部の少なくとも一部を反応槽１２に供給する。これにより、反応槽１２内で攪拌されたスラッジＳは凝集剤として機能して、被処理水におけるシリカと混合して、シリカの一部が沈殿する。 Next, in the reaction vessel 12, stirring is performed by a stirring unit (not shown) while injecting a chemical such as Na 2 CO 3 for removing a compound such as Ca which is a scale component. Here, in the second configuration example, a part of the sludge S stored in the sludge storage tank 18 is supplied to the dehydrator 15 for dehydration, while at least a part of the remaining sludge S is supplied to the reaction tank 12. do. As a result, the sludge S stirred in the reaction vessel 12 functions as a coagulant and mixes with the silica in the water to be treated, and a part of the silica precipitates.
　スラッジＳが沈降した反応槽１２から、ポンプ１４によってスラッジＳの少なくとも一部、好適には全部を汚泥貯留槽１８に供給する。ここで、汚泥貯留槽１８に貯留されたスラッジＳのうちの脱水機１５に供給されるスラッジＳの量は、初期状態におけるスラッジＳの量に対して増加した増加量分とすることが好ましい。 From the reaction tank 12 in which the sludge S has settled, at least a part, preferably all of the sludge S is supplied to the sludge storage tank 18 by the pump 14. Here, it is preferable that the amount of sludge S supplied to the dehydrator 15 among the sludge S stored in the sludge storage tank 18 is an increase amount increased with respect to the amount of sludge S in the initial state.
　次に、反応槽１２において、ｐＨ調整剤を添加する一方、攪拌部（図示せず）によって攪拌を行う。これにより、スラッジＳが再度攪拌されて懸濁状態となる。第２構成例においては、懸濁状態となったスラッジＳが凝集剤として機能して、被処理水からシリカの一部がスラッジＳに吸着され、沈殿することによって除去される。なお、上述したシリカ濃度計によって計測されたシリカ濃度に応じて、ＰＡＣをさらに添加しても良い。ＰＡＣを添加する場合、添加量はシリカ濃度の１当量以上２当量以下が好ましい。スラッジＳが沈殿した後、上澄み水は、後段のｐＨ調整槽１３に供給される。その他の構成は、第１構成例と同様である。 Next, in the reaction tank 12, while adding a pH adjuster, stirring is performed by a stirring unit (not shown). As a result, the sludge S is stirred again and becomes a suspension state. In the second configuration example, the suspended sludge S functions as a coagulant, and a part of silica is adsorbed by the sludge S from the water to be treated and is removed by precipitation. In addition, PAC may be further added according to the silica concentration measured by the above-mentioned silica densitometer. When PAC is added, the addition amount is preferably 1 equivalent or more and 2 equivalents or less of the silica concentration. After the sludge S has settled, the supernatant water is supplied to the pH adjusting tank 13 in the subsequent stage. Other configurations are the same as those of the first configuration example.
　以上説明したように凝集沈殿部の第２構成例によれば、反応槽１２における凝集沈殿処理によって得られた凝集沈殿汚泥であるスラッジＳを、シリカの凝集剤として用いていることにより、第１構成例と同様の効果を得ることができる。さらに、反応槽１２からスラッジＳの少なくとも一部、好適には全部を排出させて汚泥貯留槽１８に一時的に貯留していることにより、アルミニウム凝集剤とシリカ以外の夾雑物との反応を抑制することが可能になるので、使用する薬剤の量を低減でき、薬剤のコストが低減できる。 As described above, according to the second configuration example of the coagulation sedimentation portion, sludge S, which is the coagulation sedimentation sludge obtained by the coagulation sedimentation treatment in the reaction tank 12, is used as a silica flocculant. The same effect as the configuration example can be obtained. Further, at least a part, preferably all of the sludge S is discharged from the reaction tank 12 and temporarily stored in the sludge storage tank 18, thereby suppressing the reaction between the aluminum flocculant and impurities other than silica. Therefore, the amount of the drug used can be reduced, and the cost of the drug can be reduced.
　（第３構成例）
　次に、凝集沈殿部の第３構成例について説明する。図１２は、第３構成例による凝集沈殿部を示すブロック図である。図１２に示すように、第３構成例による凝集沈殿部１０Ｃ，５０Ｃは、受入槽１１、薬注装置１９が設けられた第１反応槽１２１、第２反応槽１２２、沈殿槽１２３、ｐＨ調整槽１３、ポンプ１４、脱水機１５、シリカ濃度計１６，１７、およびろ過部２０，６０を備える。受入槽１１、ｐＨ調整槽１３、ポンプ１４、脱水機１５、シリカ濃度計１６，１７、およびろ過部２０，６０はそれぞれ、第１構成例と同様である。 (Third configuration example)
Next, a third configuration example of the coagulation-precipitation portion will be described. FIG. 12 is a block diagram showing a coagulation sedimentation portion according to the third configuration example. As shown in FIG. 12, the coagulation and settling portions 10C and 50C according to the third configuration example are the first reaction tank 121, the second reaction tank 122, the settling tank 123, and the pH adjustment provided with the receiving tank 11 and the chemical injection device 19. It includes a tank 13, a pump 14, a dehydrator 15, silica densitometers 16 and 17, and filtration units 20 and 60. The receiving tank 11, the pH adjusting tank 13, the pump 14, the dehydrator 15, the silica densitometers 16 and 17, and the filtration units 20 and 60 are the same as in the first configuration example, respectively.
　（反応工程）
　反応部を構成する反応槽としての第１反応槽１２１においては、シリカを含む被処理水を塩基性とするように、ｐＨ調整部（図示せず）によってｐＨが調整され、例えば８以上１２以下、好適には１０．５程度に調整される。第１反応槽１２１においては、主としてシリカ以外のスケール成分として、Ｃａの難溶性塩などを除去するために、例えばＮａ2ＣＯ3などの凝集剤が注入される。第１反応槽１２１においては、攪拌部１２１ａによって撹拌が実行され、被処理水は懸濁状態となる。被処理水は、第１反応槽１２１の上部から越流させて第２反応槽１２２の下部に供給される。 (Reaction process)
In the first reaction tank 121 as a reaction tank constituting the reaction unit, the pH is adjusted by a pH adjustment unit (not shown) so that the water to be treated containing silica is basic, for example, 8 or more and 12 or less. , Preferably adjusted to about 10.5. In the first reaction vessel 121, a flocculant such as Na 2 CO 3 is injected mainly as a scale component other than silica in order to remove a sparingly soluble salt of Ca. In the first reaction tank 121, stirring is executed by the stirring unit 121a, and the water to be treated is in a suspended state. The water to be treated overflows from the upper part of the first reaction tank 121 and is supplied to the lower part of the second reaction tank 122.
　被処理水が第２反応槽１２２に供給されると、第２反応槽１２２には、凝集剤として、後段の沈殿槽１２３において採取された凝集沈殿汚泥であるスラッジＳが添加される。他方、反応部を構成する反応槽としての第２反応槽１２２には、必要に応じて、第２反応槽１２２に設けられた凝集剤添加部（図示せず）によって、凝集剤として、例えばＰＡＣなどのアルミニウム塩が添加される。第２反応槽１２２に添加されるＰＡＣの添加量は、シリカ濃度計１６，１７により計測されたシリカ濃度の計測値に基づいて決定される。第２反応槽１２２においては、攪拌部１２２ａによって撹拌が実行され、被処理水は懸濁状態となる。被処理水は、第２反応槽１２２から沈殿槽１２３に供給される。なお、後段のシリカ濃度計１７により計測されたシリカ濃度が所定のシリカ濃度以下であれば、ＰＡＣなどのアルミニウム塩を添加しなくても良い。 When the water to be treated is supplied to the second reaction tank 122, sludge S, which is the coagulation sediment sludge collected in the sedimentation tank 123 in the subsequent stage, is added to the second reaction tank 122 as a coagulant. On the other hand, in the second reaction tank 122 as a reaction tank constituting the reaction unit, if necessary, a coagulant addition part (not shown) provided in the second reaction tank 122 can be used as a coagulant, for example, PAC. Aluminum salts such as are added. The amount of PAC added to the second reaction vessel 122 is determined based on the measured value of the silica concentration measured by the silica densitometers 16 and 17. In the second reaction tank 122, stirring is executed by the stirring unit 122a, and the water to be treated is in a suspended state. The water to be treated is supplied from the second reaction tank 122 to the settling tank 123. If the silica concentration measured by the silica densitometer 17 in the subsequent stage is equal to or less than the predetermined silica concentration, it is not necessary to add an aluminum salt such as PAC.
　（沈殿工程）
　沈殿槽１２３においては、被処理水が静置されることより、攪拌されたスラッジＳが凝集剤として機能し、被処理水に含有されたシリカと混合してシリカを含むスラッジＳが沈殿する。すなわち、第２反応槽１２２において、懸濁状態となったスラッジＳが凝集剤として機能して、被処理水からシリカの一部がスラッジＳに吸着され、沈殿槽１２３において沈殿することによって除去される。なお、沈殿槽１２３において、ｐＨ調整部（図示せず）によって、被処理水のｐＨを、８以上１２以下、好適には１０．５程度に調整しても良い。 (Precipitation process)
In the settling tank 123, since the water to be treated is allowed to stand, the agitated sludge S functions as a coagulant and mixes with the silica contained in the water to be treated to precipitate the sludge S containing silica. That is, in the second reaction tank 122, the suspended sludge S functions as a coagulant, and a part of silica is adsorbed on the sludge S from the water to be treated and is removed by precipitating in the settling tank 123. To. In the settling tank 123, the pH of the water to be treated may be adjusted to 8 or more and 12 or less, preferably about 10.5 by a pH adjusting unit (not shown).
　（汚泥輸送工程）
　沈殿槽１２３において沈殿したスラッジＳの少なくとも一部は、汚泥輸送部としてのポンプ１４によって引き抜かれる。ポンプ１４によって引き抜くスラッジＳの量は、沈殿槽１２３内におけるスラッジＳの略全量としても良い。この場合、ポンプ１４は、引き抜いたスラッジＳの一部、例えばスラッジＳの沈殿量の２０％や、引き抜く周期の時間において沈殿した量の分を、例えばフィルタープレスなどの脱水機１５に供給することができる。この場合、沈殿槽１２３に沈殿しているスラッジＳの全沈殿量の８０％分や、引き抜く周期の時間において沈殿した分と略同量の古いスラッジＳを除いた残部が、第２反応槽１２２に投入される。 (Sludge transportation process)
At least a part of the sludge S settled in the settling tank 123 is pulled out by the pump 14 as a sludge transport unit. The amount of sludge S extracted by the pump 14 may be substantially the total amount of sludge S in the settling tank 123. In this case, the pump 14 supplies a part of the extracted sludge S, for example, 20% of the sedimentation amount of the sludge S, or the amount of sedimentation during the time of the extraction cycle to the dehydrator 15 such as a filter press. Can be done. In this case, 80% of the total amount of sludge S settled in the settling tank 123 and the balance excluding the old sludge S, which is substantially the same amount as the amount settled during the time of the withdrawal cycle, are the second reaction tank 122. Is thrown into.
　また、ポンプ１４は、沈殿槽１２３内におけるスラッジＳの一部だけ引き抜くようにしても良い。この場合、ポンプ１４によって引き抜かれたスラッジＳにおいて、被処理水との接触が累計で所定回数以上、例えば５回以上となったスラッジＳを脱水機１５に供給することも可能である。また、ポンプ１４は、沈殿槽１２３においては、略一定量のスラッジＳが残留するように引き抜き量を調整することも可能である。ここで、一定量は、スラッジＳを引き抜く１周期分の時間において増加するスラッジＳの量の５倍程度とすることができる。これにより、スラッジＳにおいて凝集剤としての機能を確保できる。 Further, the pump 14 may pull out only a part of the sludge S in the settling tank 123. In this case, the sludge S drawn by the pump 14 can be supplied to the dehydrator 15 with the sludge S having been in contact with the water to be treated a total of a predetermined number of times or more, for example, five times or more. Further, the pump 14 can adjust the withdrawal amount so that a substantially constant amount of sludge S remains in the settling tank 123. Here, the constant amount can be about five times the amount of sludge S that increases in the time for one cycle of pulling out the sludge S. Thereby, the function as a flocculant can be ensured in the sludge S.
　引き抜かれたスラッジＳの一部は、ポンプ１４によって第２反応槽１２２に供給される。引き抜かれたスラッジＳの残部は、脱水機１５に供給されて脱水され、脱水ケーキとなって廃棄または所定の用途に再利用される。 A part of the sludge S extracted is supplied to the second reaction tank 122 by the pump 14. The balance of the extracted sludge S is supplied to the dehydrator 15 to be dehydrated, and becomes a dehydrated cake for disposal or reuse for a predetermined purpose.
　沈殿槽１２３の後段である被処理水の流出側で、ｐＨ調整槽１３の前段である流入側に、シリカ濃度計１７が設けられている。シリカ濃度計１７によって、例えば６分～１０分の間隔で継続して沈殿槽１２３の上澄み水のシリカ濃度が計測される。その後、シリカ濃度計１６，１７によって計測されたシリカ濃度に基づいたフィードバック制御によって、第２反応槽１２２におけるアルミニウム塩の添加量が決定される。具体的に、第２反応槽１２２にスラッジＳが添加されて、懸濁状態のスラッジＳが凝集剤として機能することにより、被処理水中のシリカが除去される。続いて、シリカ濃度計１７によって計測されたシリカ濃度が、シリカ濃度計１６によって計測されたシリカ濃度から所望とするシリカ濃度以下になるために必要なアルミニウム塩の量を、アルミニウム塩の添加量に決定する。アルミニウム塩としてＰＡＣを添加する場合、添加量は、計測されたシリカ濃度の１当量以上２当量以下が好ましい。これにより、従来に比して、アルミニウム塩の添加量を低減できる。 A silica densitometer 17 is provided on the outflow side of the water to be treated, which is the subsequent stage of the settling tank 123, and on the inflow side, which is the front stage of the pH adjustment tank 13. The silica concentration meter 17 continuously measures the silica concentration of the supernatant water of the settling tank 123, for example, at intervals of 6 to 10 minutes. After that, the amount of aluminum salt added to the second reaction tank 122 is determined by feedback control based on the silica concentration measured by the silica densitometers 16 and 17. Specifically, the sludge S is added to the second reaction tank 122, and the suspended sludge S functions as a coagulant to remove silica in the water to be treated. Subsequently, the amount of aluminum salt required for the silica concentration measured by the silica concentration meter 17 to be equal to or less than the desired silica concentration from the silica concentration measured by the silica concentration meter 16 is added to the amount of aluminum salt added. decide. When PAC is added as an aluminum salt, the amount added is preferably 1 equivalent or more and 2 equivalents or less of the measured silica concentration. As a result, the amount of aluminum salt added can be reduced as compared with the conventional case.
　なお、上述した凝集沈殿部１０Ｃ，５０Ｃにおいて、第１反応槽１２１、第２反応槽１２２、および沈殿槽１２３をそれぞれ複数設け、第１反応槽１２１、第２反応槽１２２、および沈殿槽１２３からなる水処理系列を複数並列させて、被処理水を処理可能な２系列や３系列などの複数系列から構成しても良い。 In the coagulation and settling portions 10C and 50C described above, a plurality of first reaction tanks 121, second reaction tanks 122, and settling tanks 123 are provided, respectively, from the first reaction tank 121, the second reaction tank 122, and the settling tank 123. A plurality of water treatment series may be arranged in parallel to form a plurality of series such as two series or three series capable of treating the water to be treated.
　また、上述した凝集沈殿部１０Ｃ，５０Ｃにおいて、被処理水の流れ方向に沿って第１反応槽１２１の上流側に、少なくとも１槽の他の反応槽を設けても良い。また、被処理水の流れ方向に沿った第１反応槽１２１と第２反応槽１２２の間に、さらに少なくとも１槽の他の反応槽を設けても良い。これらの場合、第２反応槽１２２を、反応部を構成する複数の反応槽のうちの、被処理水の流れ方向に沿った最下流の反応槽としても良い。また、被処理水の流れ方向に沿って第２反応槽１２２の下流側に、さらに少なくとも１槽の反応槽が設けられていても良い。この場合、第１反応槽１２１を、反応部を構成する複数の反応槽において、被処理水の流れ方向に沿った最上流の反応槽としても良い。さらに、これらの構成を組み合わせることも可能である。すなわち、反応部を３槽以上の複数の反応槽から構成し、これらの３槽以上の反応槽のうちの１つの反応槽を第１反応槽１２１とし、第１反応槽１２１より下流側の少なくとも１槽の反応槽のうちの１つの反応槽を第２反応槽１２２としても良い。 Further, in the coagulation sedimentation portions 10C and 50C described above, at least one other reaction tank may be provided on the upstream side of the first reaction tank 121 along the flow direction of the water to be treated. Further, at least one other reaction tank may be provided between the first reaction tank 121 and the second reaction tank 122 along the flow direction of the water to be treated. In these cases, the second reaction tank 122 may be the most downstream reaction tank along the flow direction of the water to be treated among the plurality of reaction tanks constituting the reaction unit. Further, at least one reaction tank may be further provided on the downstream side of the second reaction tank 122 along the flow direction of the water to be treated. In this case, the first reaction tank 121 may be the most upstream reaction tank along the flow direction of the water to be treated in a plurality of reaction tanks constituting the reaction unit. Furthermore, it is possible to combine these configurations. That is, the reaction unit is composed of a plurality of reaction tanks having three or more tanks, and one of these three or more reaction tanks is designated as the first reaction tank 121, and at least on the downstream side of the first reaction tank 121. One of the reaction tanks in one tank may be used as the second reaction tank 122.
　また、第１反応槽１２１を複数の反応槽から構成しても良く、第２反応槽１２２を複数の反応槽から構成しても良い。同様に、沈殿部を構成する沈殿槽１２３を、被処理水が直列に輸送される複数の沈殿槽から構成しても良い。 Further, the first reaction tank 121 may be composed of a plurality of reaction tanks, and the second reaction tank 122 may be composed of a plurality of reaction tanks. Similarly, the settling tank 123 constituting the settling portion may be composed of a plurality of settling tanks in which the water to be treated is transported in series.
　（アルミニウム除去工程）
　沈殿槽１２３において得られた上澄み水は、ｐＨ調整槽１３に供給されてｐＨが４以上８以下の例えば６．５程度に調整される。これにより、上澄み水のＡｌが不溶性になって除去される。ｐＨ調整槽１３においてｐＨが調整された調整水であるＡｌ含有水は、ろ過部２０，６０に供給される。なお、ｐＨ調整槽１３においてｐＨが調整されたＡｌ含有水の一部を第２反応槽１２２に戻すようにしても良い。 (Aluminum removal process)
The supernatant water obtained in the settling tank 123 is supplied to the pH adjusting tank 13 and adjusted to a pH of 4 or more and 8 or less, for example, about 6.5. As a result, Al in the supernatant water becomes insoluble and is removed. The Al-containing water, which is the pH-adjusted water in the pH-adjusting tank 13, is supplied to the filtration units 20 and 60. A part of the Al-containing water whose pH has been adjusted in the pH adjusting tank 13 may be returned to the second reaction tank 122.
　ろ過部２０，６０においては、ｐＨ調整槽１３から供給された調整水からＡｌを除去するろ過処理が行われる。これにより、処理水が得られる。 In the filtration units 20 and 60, a filtration process is performed to remove Al from the adjustment water supplied from the pH adjustment tank 13. As a result, treated water is obtained.
　上述したように、シリカの処理槽である第２反応槽１２２の前段に、シリカ以外の夾雑物を除去する第１反応槽１２１を設けていることにより、第２反応槽１２２において、アルミニウム塩がシリカ以外の物質によって消費されるのを抑制することが可能となる。 As described above, by providing the first reaction tank 121 for removing impurities other than silica in the front stage of the second reaction tank 122 which is a silica treatment tank, the aluminum salt is generated in the second reaction tank 122. It is possible to suppress consumption by substances other than silica.
　以上説明したように凝集沈殿部の第３構成例によれば、沈殿槽１２３において沈殿した凝集沈殿汚泥であるスラッジＳを、沈殿槽１２３の前段の反応槽、具体的には第２反応槽１２２に再度投入して被処理水からシリカを除去している。すなわち、第３構成例においては、沈殿槽１２３において凝集沈殿したスラッジＳを、第２反応槽１２２に投入して、改めてシリカの吸着核、すなわち凝集剤として使用しているので、シリカの除去に要するＰＡＣなどの薬剤の添加量を低減できる。さらに、スラッジＳを凝集剤として使用していることにより、排出するスラッジＳの量を低減できるので、排出されたスラッジＳの後処理に要するコストを低減することが可能となる。 As described above, according to the third configuration example of the coagulation sedimentation portion, the sludge S, which is the coagulation sediment sludge settled in the sedimentation tank 123, is transferred to the reaction tank in the previous stage of the sedimentation tank 123, specifically, the second reaction tank 122. The silica is removed from the water to be treated. That is, in the third configuration example, the sludge S coagulated and precipitated in the settling tank 123 is put into the second reaction tank 122 and used again as an adsorption nucleus of silica, that is, as a coagulant, so that the silica can be removed. The amount of chemicals such as PAC required can be reduced. Further, since the sludge S is used as a flocculant, the amount of the sludge S to be discharged can be reduced, so that the cost required for the post-treatment of the discharged sludge S can be reduced.
　（第４構成例）
　次に、第４構成例による凝集沈殿部について説明する。図１３は、第４構成例による凝集沈殿部を示すブロック図である。図１３に示すように、第４構成例による凝集沈殿部１０Ｄ，５０Ｄは、第３構成例と同様に、受入槽１１、第１反応槽１２１、第２反応槽１２２、沈殿槽１２３，ｐＨ調整槽１３、ポンプ１４、脱水機１５、シリカ濃度計１６，１７、薬注装置１９、およびろ過部２０，６０を備える。 (Fourth configuration example)
Next, the coagulation-precipitation portion according to the fourth configuration example will be described. FIG. 13 is a block diagram showing a coagulation sedimentation portion according to the fourth configuration example. As shown in FIG. 13, the coagulation and settling portions 10D and 50D according to the fourth configuration example have the receiving tank 11, the first reaction tank 121, the second reaction tank 122, the settling tank 123, and the pH adjustment, similarly to the third configuration example. It includes a tank 13, a pump 14, a dehydrator 15, silica densitometers 16 and 17, a chemical injection device 19, and filtration units 20 and 60.
　第４構成例においては、沈殿槽１２３において、被処理水が静置されることより、攪拌されたスラッジＳが凝集剤として機能し、被処理水に含有されたシリカと混合してシリカを含むスラッジＳが沈殿する。沈殿したスラッジＳの少なくとも一部は、ポンプ１４によって引き抜かれる。引き抜くスラッジＳの量は、沈殿槽１２３内におけるスラッジＳの増加量分とすることが好ましいが限定されない。換言すると、沈殿槽１２３においては、略一定量のスラッジＳが残留するように引き抜き量を調整することが好ましい。第４構成例においては、第３構成例と異なり、引き抜かれたスラッジＳの一部は、ポンプ１４によって第１反応槽１２１に供給される。これにより、第１反応槽１２１には、後段の沈殿槽１２３からスラッジＳが輸送されて添加される。添加されたスラッジＳによって第１反応槽１２１内のシリカの一部が除去される。 In the fourth configuration example, since the water to be treated is allowed to stand in the settling tank 123, the agitated sludge S functions as a coagulant and is mixed with the silica contained in the water to be treated to contain silica. Sludge S precipitates. At least a part of the settled sludge S is pulled out by the pump 14. The amount of sludge S to be extracted is preferably, but is not limited to, the amount of increase in sludge S in the settling tank 123. In other words, in the settling tank 123, it is preferable to adjust the withdrawal amount so that a substantially constant amount of sludge S remains. In the fourth configuration example, unlike the third configuration example, a part of the extracted sludge S is supplied to the first reaction tank 121 by the pump 14. As a result, sludge S is transported and added to the first reaction tank 121 from the settling tank 123 in the subsequent stage. A part of silica in the first reaction tank 121 is removed by the added sludge S.
　一方、第１反応槽１２１においては、被処理水を塩基性とするようにｐＨが調整され、例えば８以上１２以下、好適には１０．５程度に調整される。また、第１反応槽１２１においては、主としてシリカ以外のスケール成分として、例えばＣａの難溶性塩などを除去するために、例えばＮａ2ＣＯ3などのＣａの凝集剤が注入される。第１反応槽１２１においては、攪拌部１２１ａによって撹拌が実行され、被処理水は懸濁状態となる。これによって、第１反応槽１２１内においては、Ｃａの凝集剤によってＣａの難溶性塩などが除去されるとともに、スラッジＳによってシリカの一部が除去される。 On the other hand, in the first reaction tank 121, the pH is adjusted so that the water to be treated is basic, for example, 8 or more and 12 or less, preferably about 10.5. Further, in the first reaction tank 121, a Ca flocculant such as Na 2 CO 3 is injected mainly as a scale component other than silica in order to remove, for example, a sparingly soluble salt of Ca. In the first reaction tank 121, stirring is executed by the stirring unit 121a, and the water to be treated is in a suspended state. As a result, in the first reaction tank 121, the sparingly soluble salt of Ca is removed by the flocculant of Ca, and a part of silica is removed by the sludge S.
　懸濁状態の被処理水は、第１反応槽１２１の上部から越流させて第２反応槽１２２の下部に供給される。被処理水のシリカ濃度は、第１反応槽１２１の後段で第２反応槽１２２の前段に設けられたシリカ濃度計１６により計測される。なお、第１反応槽１２１において被処理水のシリカ濃度を計測しても良い。 The suspended water to be treated overflows from the upper part of the first reaction tank 121 and is supplied to the lower part of the second reaction tank 122. The silica concentration of the water to be treated is measured by a silica densitometer 16 provided in the subsequent stage of the first reaction tank 121 and in front of the second reaction tank 122. The silica concentration of the water to be treated may be measured in the first reaction tank 121.
　第４構成例においては、第１反応槽１２１から流出された被処理水のシリカ濃度と、沈殿槽１２３から流出された被処理水のシリカ濃度とに基づいて、第２反応槽１２２内の被処理水に添加する、例えばＰＡＣなどのアルミニウム塩の添加量が決定される。すなわち、シリカ濃度計１７によって、例えば６分～１０分の間隔で継続して沈殿槽１２３の上澄み水のシリカ濃度が計測される。同様にして、シリカ濃度計１６によって、例えば６分～１０分の間隔で第１反応槽１２１から流出された被処理水のシリカ濃度が計測される。シリカ濃度計１６，１７によって計測されたシリカ濃度に基づいたフィードバック制御によって、第２反応槽１２２におけるアルミニウム塩の添加量が決定される。その他の構成は、第３構成例と同様である。 In the fourth configuration example, the subject in the second reaction tank 122 is based on the silica concentration of the water to be treated flowing out from the first reaction tank 121 and the silica concentration of the water to be treated flowing out from the settling tank 123. The amount of aluminum salt added to the treated water, such as PAC, is determined. That is, the silica concentration of the supernatant water of the settling tank 123 is continuously measured by the silica densitometer 17 at intervals of, for example, 6 to 10 minutes. Similarly, the silica concentration meter 16 measures the silica concentration of the water to be treated flowing out of the first reaction tank 121 at intervals of, for example, 6 to 10 minutes. The amount of aluminum salt added to the second reaction vessel 122 is determined by feedback control based on the silica concentration measured by the silica densitometers 16 and 17. Other configurations are the same as those of the third configuration example.
　以上説明したように凝集沈殿部の第４構成例によれば、第１反応槽１２１、第２反応槽１２２、および沈殿槽１２３における凝集沈殿処理によって得られた凝集沈殿汚泥であるスラッジＳを、シリカの凝集剤として用いていることにより、第１～第３構成例と同様の効果を得ることができる。さらに、第４構成例によれば、第１反応槽１２１に凝集剤として機能するスラッジＳを投入して、第１反応槽１２１の下流側においてシリカ濃度を計測していることにより、スラッジＳに吸着するシリカの濃度をより正確に計測することができるので、第２反応槽１２２において添加するアルミニウム塩の添加量を最適化できる。また、受入槽１１から第１反応槽１２１の下部に被処理水を注入し、第１反応槽１２１の上部から被処理水を越流させて第２反応槽１２２の下部に注入していることにより、スラッジＳの侵入量を抑制できるので、新たに注入するＰＡＣなどのアルミニウム塩とスラッジＳとの反応を抑制でき、第３構成例に比してシリカの除去率をさらに向上できる。 As described above, according to the fourth configuration example of the coagulation sedimentation portion, sludge S, which is the coagulation sedimentation sludge obtained by the coagulation sedimentation treatment in the first reaction tank 121, the second reaction tank 122, and the sedimentation tank 123, is subjected to. By using it as a dispersant for silica, the same effect as that of the first to third constituent examples can be obtained. Further, according to the fourth configuration example, the sludge S functioning as a coagulant is charged into the first reaction tank 121, and the silica concentration is measured on the downstream side of the first reaction tank 121, whereby the sludge S is charged. Since the concentration of silica adsorbed can be measured more accurately, the amount of aluminum salt added in the second reaction vessel 122 can be optimized. Further, the water to be treated is injected from the receiving tank 11 to the lower part of the first reaction tank 121, and the water to be treated is overflowed from the upper part of the first reaction tank 121 and injected into the lower part of the second reaction tank 122. As a result, the amount of sludge S invading can be suppressed, so that the reaction between the newly injected aluminum salt such as PAC and sludge S can be suppressed, and the silica removal rate can be further improved as compared with the third configuration example.
　上述した第１～第４構成例による凝集沈殿部およびろ過部については、第１凝集沈殿部１０と第２凝集沈殿部５０とを同様の構成としても良く、互いに異なる構成としても良い。 Regarding the coagulation sedimentation portion and the filtration portion according to the above-mentioned first to fourth configuration examples, the first coagulation sedimentation portion 10 and the second coagulation sedimentation portion 50 may have the same configuration or different configurations.
　上述した第１～第４構成例において凝集剤として用いる薬剤は、被処理水に添加することによって凝集沈殿を生じさせる凝集剤と、この凝集剤によって凝集沈殿されたシリカと、を含み、被処理水に凝集剤を添加して凝集沈殿した凝集沈殿汚泥からなる薬剤である。ここで、被処理水に添加することによって凝集沈殿を生じさせる凝集剤とは、アルミニウム塩、マグネシウム塩、鉄塩、およびポリマー系凝集剤から選ばれた少なくとも１種類の化合物から構成される。 The chemicals used as the coagulant in the first to fourth constituent examples described above include a coagulant that causes coagulation and precipitation by adding to the water to be treated, and silica that coagulates and precipitates by the coagulant, and is to be treated. It is a chemical consisting of coagulated sediment sludge that is coagulated and precipitated by adding a coagulant to water. Here, the flocculant that causes coagulation / precipitation by adding to the water to be treated is composed of at least one compound selected from an aluminum salt, a magnesium salt, an iron salt, and a polymer-based flocculant.
　また、上述した第１～第４構成例において凝集剤として用いる薬剤は、被処理水に凝集剤を添加する工程と、被処理水に含まれるシリカを凝集沈殿させて凝集沈殿汚泥を生成する工程と、含む製造方法によって製造可能である。この際、被処理水のｐＨを８以上１２以下に調整することが好ましい。 Further, the chemicals used as the coagulant in the above-mentioned first to fourth constitutional examples include a step of adding the coagulant to the water to be treated and a step of coagulating and precipitating silica contained in the water to be treated to generate coagulated sediment sludge. It can be manufactured by a manufacturing method including. At this time, it is preferable to adjust the pH of the water to be treated to 8 or more and 12 or less.
　（正浸透装置）
　次に、第１～第４の実施形態による水処理装置１～８に採用される正浸透装置の構成について説明する。 (Forward osmosis device)
Next, the configuration of the forward osmosis device adopted in the water treatment devices 1 to 8 according to the first to fourth embodiments will be described.
　まず、従来の正浸透装置においては、水分離ドロー溶液を正浸透装置におけるドロー溶液として循環させて用いると、高温の再生ドロー溶液の冷却が不十分になるという問題があった。そこで、高温のドロー溶液を冷却するための冷却機構を設ける方法が考えられるが、冷却機構を新たに設けると水処理装置に要するエネルギーが増加してランニングコストが増加するという問題が生じる。そのため、正浸透装置において、配管構造を可能な限り簡素化しつつ、冷却や加熱に要する消費エネルギーを抑制して、エネルギーの収支を安定化できる技術が求められていた。以下に説明する正浸透装置の第１装置例、第２装置例、第３装置例、および第４装置例は、配管構造を簡素にしつつ、冷却や加熱に要する消費エネルギーを抑制して、エネルギーの収支を安定化できる正浸透装置である。 First, in the conventional forward osmosis device, when the water-separated draw solution is circulated and used as the draw solution in the forward osmosis device, there is a problem that the cooling of the high-temperature regenerated draw solution becomes insufficient. Therefore, a method of providing a cooling mechanism for cooling the high-temperature draw solution can be considered, but if a cooling mechanism is newly provided, there arises a problem that the energy required for the water treatment device increases and the running cost increases. Therefore, in the forward osmosis device, there has been a demand for a technique capable of stabilizing the energy balance by suppressing the energy consumption required for cooling and heating while simplifying the piping structure as much as possible. In the first device example, the second device example, the third device example, and the fourth device example of the forward osmosis device described below, the energy consumption required for cooling and heating is suppressed while simplifying the piping structure, and the energy is reduced. It is a forward osmosis device that can stabilize the balance of energy.
　（第１装置例による正浸透装置）
　まず、本発明の実施形態による水処理装置１～８の正浸透装置７０の第１装置例について説明する。図１４は、第１装置例による正浸透装置を模式的に示すブロック図である。図１４に示すように、第１装置例による正浸透装置７１は、膜モジュール７１１、熱交換器７１２，７１３、加熱器７１４、分離槽７１５、および最終処理ユニット７１６を備えて構成される。 (Forward osmosis device according to the first device example)
First, an example of the first device of the forward osmosis device 70 of the water treatment devices 1 to 8 according to the embodiment of the present invention will be described. FIG. 14 is a block diagram schematically showing a forward osmosis device according to the first device example. As shown in FIG. 14, the forward osmosis device 71 according to the first device example includes a membrane module 711, a heat exchanger 712, 713, a heater 714, a separation tank 715, and a final processing unit 716.
　膜モジュール７１１は、例えば円筒形または箱形の容器であって、内部に正浸透膜としての半透膜７１１ａが設置されることによって、内部が半透膜７１１ａによって２つの室に仕切られる。膜モジュール７１１の形態は、例えばスパイラルモジュール型、積層モジュール型、中空糸モジュール型などの種々の形態を挙げることができる。膜モジュール７１１としては、公知の半透膜装置を用いることができ、市販品を用いることもできる。 The membrane module 711 is, for example, a cylindrical or box-shaped container, and the inside is divided into two chambers by the semipermeable membrane 711a by installing the semipermeable membrane 711a as a forward osmosis membrane inside. Examples of the form of the membrane module 711 include various forms such as a spiral module type, a laminated module type, and a hollow fiber module type. As the membrane module 711, a known semipermeable membrane device can be used, and a commercially available product can also be used.
　膜モジュール７１１に設けられた半透膜７１１ａは、水を選択的に透過できるものが好ましく、ＦＯ膜が用いられるが、ＲＯ膜を用いても良い。半透膜７１１ａの分離層の材質は、特に限定されるものではなく、例えば、酢酸セルロース系、ポリアミド系、ポリエチレンイミン系、ポリスルホン系、またはポリベンゾイミダゾール系などの材質を挙げることができる。半透膜７１１ａの構成は、分離層に用いられる材質を１種類（１層）のみから構成しても良く、分離層を物理的に支持して実質的に分離に寄与しない支持層を有する２層以上から構成しても良い。支持層としてはポリスルホン系、ポリケトン系、ポリエチレン系、ポリエチレンテレフタラート系、一般的な不織布などの材質を挙げることができる。なお、半透膜７１１ａの形態についても限定されるものではなく、平膜、管状膜、または中空糸など種々の形態の膜を用いることができる。 The semipermeable membrane 711a provided in the membrane module 711 is preferably one that can selectively permeate water, and an FO membrane is used, but an RO membrane may also be used. The material of the separation layer of the semipermeable membrane 711a is not particularly limited, and examples thereof include materials such as cellulose acetate-based, polyamide-based, polyethyleneimine-based, polysulfone-based, and polybenzimidazole-based. The semipermeable membrane 711a may be composed of only one type (one layer) of the material used for the separation layer, and has a support layer that physically supports the separation layer and does not substantially contribute to separation2. It may be composed of layers or more. Examples of the support layer include materials such as polysulfone-based, polyketone-based, polyethylene-based, polyethylene terephthalate-based, and general non-woven fabric. The form of the semipermeable membrane 711a is also not limited, and various forms of membranes such as flat membranes, tubular membranes, and hollow fibers can be used.
　膜モジュール７１１の内部において半透膜７１１ａによって仕切られた一方の室に、含水溶液を流すことができ、他方の室に吸水溶液であるドロー溶液を流すことができる。ドロー溶液の膜モジュール７１１への導入圧力は、０．１ＭＰａ以上０．５ＭＰａ以下、第１装置例においては例えば０．２ＭＰａである。含水溶液は、例えば濃縮水、海水、かん水、汽水、工業排水、随伴水、もしくは下水、または必要に応じてこれらの水に対してろ過処理を施した、溶媒として水を含む含水溶液である。 An aqueous solution containing an aqueous solution can be flowed into one chamber partitioned by the semipermeable membrane 711a inside the membrane module 711, and a draw solution which is an absorbing aqueous solution can be flowed into the other chamber. The pressure for introducing the draw solution into the membrane module 711 is 0.1 MPa or more and 0.5 MPa or less, and in the first apparatus example, for example, 0.2 MPa. The aqueous solution contains, for example, concentrated water, seawater, brackish water, brackish water, industrial wastewater, accompanying water, or sewage, or, if necessary, filtered treatment of these waters and contains water as a solvent.
　ドロー溶液としては、少なくとも１つの曇点を有する温度感応性吸水剤（ポリマー）を主体とする溶液が用いられる。温度感応性吸水剤とは、低温においては親水性で水に良く溶けて吸水量が多くなる一方、温度の上昇にしたがって吸水量が低下して、所定温度以上になると疎水性化し溶解度が低下する物質である。 As the draw solution, a solution mainly composed of a temperature-sensitive water absorbing agent (polymer) having at least one cloud point is used. A temperature-sensitive water absorbent is hydrophilic at low temperatures and dissolves well in water to increase the amount of water absorption. On the other hand, the amount of water absorption decreases as the temperature rises, and when the temperature rises above a predetermined temperature, it becomes hydrophobic and the solubility decreases. It is a substance.
　第１装置例においてポリマーは、少なくとも疎水部および親水部が含まれ、基本骨格にエチレンオキシド群とプロピレンオキシドおよびブチレンオキシドからなる少なくとも一方の群とを含む、ブロックまたはランダム共重合体が好ましい。基本骨格は例えば、グリセリン骨格や炭化水素骨格などが挙げられる。この一実施形態においてポリマーは、例えばエチレンオキサイドおよびプロピレンオキサイドの重合体を有する薬剤（ＧＥ１０００－ＢＢＰＰ（Ａ３）など）が用いられる。このようなポリマーにおいて、水溶性と水不溶性とが変化する温度は、曇点と呼ばれる。ドロー溶液の温度が曇点に達すると疎水性化した温度感応性吸水剤が凝集して白濁が生じる。温度感応性吸水剤は、各種界面活性剤、分散剤、または乳化剤などとして利用される。第１装置例において、ドロー溶液は、含水溶液から水を誘引する誘引物質として用いられる。膜モジュール７１１においては、含水溶液からドロー溶液に水が誘引されて、希釈されたドロー溶液（希釈ドロー溶液）が流出される。 In the first apparatus example, the polymer is preferably a block or random copolymer containing at least a hydrophobic part and a hydrophilic part, and the basic skeleton contains at least one group consisting of ethylene oxide group and propylene oxide and butylene oxide. Examples of the basic skeleton include a glycerin skeleton and a hydrocarbon skeleton. In this one embodiment, as the polymer, for example, an agent having a polymer of ethylene oxide and propylene oxide (GE1000-BBPP (A3) or the like) is used. In such polymers, the temperature at which water solubility and water insolubility change is called the cloud point. When the temperature of the draw solution reaches the cloud point, the hydrophobic temperature-sensitive water absorbent aggregates and becomes cloudy. The temperature-sensitive water absorbent is used as various surfactants, dispersants, emulsifiers and the like. In the first device example, the draw solution is used as an attractant to attract water from the aqueous solution. In the membrane module 711, water is attracted from the aqueous solution to the draw solution, and the diluted draw solution (diluted draw solution) flows out.
　熱交換器７１２は、膜モジュール７１１に対して含水溶液の流れ方向に沿った上流側に設けられる。熱交換器７１２は、後述する分離槽７１５から流出される再利用されるドロー溶液（以下、再生ドロー溶液）の流れ方向に沿った下流側に設けられ、分離槽７１５から流出される再生ドロー溶液と外部から供給される含水溶液との間で熱交換を行う。熱交換器７１２に流入される含水溶液の流量は、膜モジュール７１１に供給される再生ドロー溶液の温度が所定温度になるように温度制御される。膜モジュール７１１に供給される再生ドロー溶液は、２５℃以上５０℃以下の、例えば４０℃程度の所定温度に温度制御される。なお、再生ドロー溶液の温度を所望温度に維持しつつ、膜モジュール７１１に供給する含水溶液の流量を一定にする必要がある場合には、膜モジュール７１１と熱交換器７１２との間に、調整弁としてのブロー弁（図示せず）を設けることが望ましい。 The heat exchanger 712 is provided on the upstream side of the membrane module 711 along the flow direction of the aqueous solution. The heat exchanger 712 is provided on the downstream side along the flow direction of the recycled draw solution (hereinafter referred to as the regenerated draw solution) flowing out from the separation tank 715, which will be described later, and the regenerated draw solution flowing out from the separation tank 715. Heat exchange is performed between the surface and the aqueous solution supplied from the outside. The flow rate of the aqueous solution flowing into the heat exchanger 712 is temperature-controlled so that the temperature of the regenerated draw solution supplied to the membrane module 711 becomes a predetermined temperature. The temperature of the regenerated draw solution supplied to the membrane module 711 is controlled to a predetermined temperature of 25 ° C. or higher and 50 ° C. or lower, for example, about 40 ° C. If it is necessary to keep the temperature of the regenerated draw solution at a desired temperature and keep the flow rate of the aqueous solution supplied to the membrane module 711 constant, adjust the temperature between the membrane module 711 and the heat exchanger 712. It is desirable to provide a blow valve (not shown) as a valve.
　熱交換器７１３は、膜モジュール７１１に対して、希釈ドロー溶液の流れ方向に沿った下流側に設けられている。また、熱交換器７１３は、後述する分離槽７１５から流出される水リッチ溶液の流れ方向に沿った下流側に設けられ、膜モジュール７１１から流出された希釈ドロー溶液と、分離槽７１５によって得られた水リッチ溶液との間で、熱交換を行う。 The heat exchanger 713 is provided on the downstream side of the membrane module 711 along the flow direction of the diluted draw solution. Further, the heat exchanger 713 is provided on the downstream side along the flow direction of the water-rich solution flowing out from the separation tank 715, which will be described later, and is obtained by the diluted draw solution flowing out from the membrane module 711 and the separation tank 715. Heat exchange with the water-rich solution.
　ドロー溶液の加熱手段としての加熱器７１４は、ドロー溶液の流れ方向に沿って分離槽７１５の上流側に設けられる。加熱器７１４は、膜モジュール７１１から流出して熱交換器７１３によって熱交換された希釈ドロー溶液を、曇点の温度以上に加熱する。加熱器７１４によって曇点の温度以上に加熱された希釈ドロー溶液は、ポリマーと水とに分相される。 The heater 714 as a means for heating the draw solution is provided on the upstream side of the separation tank 715 along the flow direction of the draw solution. The heater 714 heats the diluted draw solution that flows out of the membrane module 711 and is heat exchanged by the heat exchanger 713 above the cloud point temperature. The diluted draw solution heated above the cloud point temperature by the heater 714 is phase-separated into polymer and water.
　水分離手段としての分離槽７１５においては、加熱器７１４によって分相された希釈ドロー溶液が、水を主体とする水リッチ溶液とポリマーを主体として水リッチ溶液より含水率が低いドロー溶液とに分離される。水リッチ溶液より含水率が低いドロー溶液は、再生ドロー溶液として、熱交換器７１２を介して膜モジュール７１１に供給される。 In the separation tank 715 as a water separation means, the diluted draw solution phase-separated by the heater 714 is separated into a water-rich solution mainly composed of water and a draw solution mainly composed of a polymer having a lower water content than the water-rich solution. Will be done. The draw solution having a lower water content than the water-rich solution is supplied to the membrane module 711 as a regenerated draw solution via the heat exchanger 712.
　分離処理手段としての最終処理ユニット７１６は、例えばコアレッサー、活性炭吸着ユニット、ＵＦ膜ユニット、ナノろ過膜（ＮＦ膜）ユニット、またはＲＯ膜ユニットから構成される。最終処理ユニット７１６は、分離槽７１５から流出した水リッチ溶液において、残存するポリマーを水リッチ溶液から分離させて、透過水としての淡水を生成する。最終処理ユニット７１６によって分離されたポリマーを含むポリマー溶液は、廃棄したり、加熱器７１４の少なくとも上流側において希釈ドロー溶液に導入したりしても良い。さらに、分離されたポリマー溶液の一部を廃棄し、残りのポリマー溶液をドロー溶液として、少なくとも加熱器７１４の上流側または熱交換器７１３の上流側における希釈ドロー溶液に導入することも可能である。ここで、ポリマー溶液を希釈ドロー溶液に導入する方法としては、希釈ドロー溶液が流れる配管に導入する方法のみならず、希釈ドロー溶液を一時的に貯留するタンク（図示せず）に導入する方法など、種々の方法を採用することが可能である。 The final treatment unit 716 as the separation treatment means is composed of, for example, a corelesser, an activated carbon adsorption unit, a UF membrane unit, a nanofiltration membrane (NF membrane) unit, or an RO membrane unit. The final treatment unit 716 separates the remaining polymer from the water-rich solution in the water-rich solution flowing out of the separation tank 715 to produce fresh water as permeated water. The polymer solution containing the polymer separated by the final treatment unit 716 may be discarded or introduced into the diluted draw solution at least upstream of the heater 714. Further, it is also possible to discard a part of the separated polymer solution and introduce the remaining polymer solution as a draw solution into a diluted draw solution at least on the upstream side of the heater 714 or the upstream side of the heat exchanger 713. .. Here, as a method of introducing the polymer solution into the diluted draw solution, not only a method of introducing the diluted draw solution into the pipe through which the diluted draw solution flows, but also a method of introducing the diluted draw solution into a tank (not shown) for temporarily storing the diluted draw solution, etc. , Various methods can be adopted.
　（正浸透処理工程）
　次に、第１装置例による正浸透装置７１を用いた正浸透処理工程について説明する。 (Forward osmosis treatment process)
Next, the forward osmosis treatment step using the forward osmosis apparatus 71 according to the first apparatus example will be described.
　（流入側熱交換工程）
　流入側熱交換手段としての熱交換器７１２においては、流入側熱交換工程が行われる。すなわち、外部から水処理装置１に供給される含水溶液は、まず、熱交換器７１２に供給される。一方、熱交換器７１２には、分離槽７１５から流出された再生ドロー溶液が供給される。第１装置例においては、熱交換器７１２によって、再生ドロー溶液を所定温度、具体的に例えば４０℃程度の温度に調整する。後述するように、分離槽７１５には、加熱された希釈ドロー溶液が流入されるため、分離槽７１５から流出する再生ドロー溶液の温度は含水溶液よりも高温である。そこで、熱交換器７１２によって、再生ドロー溶液を降温させる。再生ドロー溶液を所定温度に降温させるために、熱交換器７１２に流入される含水溶液の流量が調整される。すなわち、熱交換器７１２において、再生ドロー溶液は含水溶液によって冷却される一方、含水溶液は再生ドロー溶液によって加熱される。なお、膜モジュール７１１と熱交換器７１２との間に調整弁としてのブロー弁（図示せず）を設けて、再生ドロー溶液の温度を所望温度に維持しつつ、膜モジュール７１１に供給する含水溶液の流量を一定に調整することも可能である。熱交換が行われて降温された再生ドロー溶液は膜モジュール７１１の他方の室に供給されるとともに、熱交換が行われて昇温された含水溶液は、膜モジュール７１１における一方の室に供給される。 (Inflow side heat exchange process)
In the heat exchanger 712 as the inflow side heat exchange means, the inflow side heat exchange step is performed. That is, the aqueous solution contained in the water treatment device 1 supplied from the outside is first supplied to the heat exchanger 712. On the other hand, the regenerated draw solution flowing out of the separation tank 715 is supplied to the heat exchanger 712. In the first device example, the regenerated draw solution is adjusted to a predetermined temperature, specifically, for example, about 40 ° C. by the heat exchanger 712. As will be described later, since the heated diluted draw solution flows into the separation tank 715, the temperature of the regenerated draw solution flowing out of the separation tank 715 is higher than that of the aqueous solution-containing solution. Therefore, the heat exchanger 712 lowers the temperature of the regenerated draw solution. The flow rate of the aqueous solution containing water flowing into the heat exchanger 712 is adjusted in order to lower the temperature of the regenerated draw solution to a predetermined temperature. That is, in the heat exchanger 712, the regenerated draw solution is cooled by the regenerated aqueous solution, while the regenerated aqueous solution is heated by the regenerated draw solution. A blow valve (not shown) as a regulating valve is provided between the membrane module 711 and the heat exchanger 712 to maintain the temperature of the regenerated draw solution at a desired temperature while supplying an aqueous solution to the membrane module 711. It is also possible to adjust the flow rate of. The regenerated draw solution heated by heat exchange is supplied to the other chamber of the membrane module 711, and the aqueous solution containing heat exchanged and heated is supplied to one chamber of the membrane module 711. Ru.
　（正浸透工程）
　正浸透手段としての膜モジュール７１１においては、第２水抽出工程としての正浸透工程が行われる。すなわち、膜モジュール７１１において、含水溶液と再生ドロー溶液とを半透膜７１１ａを介して接触させることによって、浸透圧差により含水溶液中の水が半透膜７１１ａを通過して再生ドロー溶液に移動する。含水溶液が供給される一方の室からは、水が移動して濃縮された濃縮含水溶液が流出する。再生ドロー溶液が供給される他方の室からは水が移動して希釈された希釈ドロー溶液が流出する。ここで、熱交換器７１２において、含水溶液と再生ドロー溶液との間で熱交換されていることにより、膜モジュール７１１の内部においては、互いに略同温度の含水溶液と再生ドロー溶液との間で、水が移動される。そのため、膜モジュール７１１から流出される希釈ドロー溶液の温度は、再生ドロー溶液の温度と略同程度の温度である。 (Forward penetration process)
In the membrane module 711 as the forward osmosis means, the forward osmosis step as the second water extraction step is performed. That is, in the membrane module 711, when the aqueous solution and the regenerated draw solution are brought into contact with each other via the semipermeable membrane 711a, the water in the aqueous solution passes through the semipermeable membrane 711a and moves to the regenerated draw solution due to the osmotic pressure difference. .. Water moves from one of the chambers to which the aqueous solution is supplied, and the concentrated aqueous solution flows out. Water moves from the other chamber to which the regenerated draw solution is supplied and the diluted diluted draw solution flows out. Here, in the heat exchanger 712, heat is exchanged between the aqueous solution and the regenerated draw solution, so that the aqueous solution containing substantially the same temperature and the regenerated draw solution are inside the membrane module 711. , Water is moved. Therefore, the temperature of the diluted draw solution flowing out from the membrane module 711 is substantially the same as the temperature of the regenerated draw solution.
　（加熱工程）
　加熱手段としての加熱器７１４においては、加熱工程が行われる。すなわち、正浸透工程によって含水溶液から水が移動して希釈された希釈ドロー溶液を、後述する流出側熱交換工程において昇温した後に、加熱器７１４によってさらに曇点以上の温度まで加熱することにより、ポリマーの少なくとも一部を凝集させて、相分離させる。加熱工程における加熱温度は、加熱器７１４を制御することによって調整可能である。なお、加熱温度は、１００℃以下が好ましく、第１装置例において加熱温度は、曇点以上１００℃以下の例えば８８℃である。 (Heating process)
In the heater 714 as a heating means, a heating step is performed. That is, the diluted draw solution diluted by moving water from the aqueous solution in the forward osmosis step is heated in the outflow side heat exchange step described later, and then heated to a temperature higher than the cloud point by the heater 714. , At least a portion of the polymer is agglomerated and phase separated. The heating temperature in the heating step can be adjusted by controlling the heater 714. The heating temperature is preferably 100 ° C. or lower, and in the first apparatus example, the heating temperature is, for example, 88 ° C., which is equal to or higher than the cloud point and 100 ° C. or lower.
　（水分離工程）
　分離槽７１５においては、水分離工程が行われる。すなわち、分離槽７１５において、希釈ドロー溶液は、水分を多く含有する水リッチ溶液と、ポリマーを高濃度に含む濃縮された再生ドロー溶液とに分離される。なお、分離槽７１５における圧力は大気圧である。水リッチ溶液と再生ドロー溶液との相分離は、曇点以上の液温で静置することによって行うことができる。第１装置例において液温は、曇点以上１００℃以下の例えば８８℃である。希釈ドロー溶液から分離されて濃縮されたドロー溶液は、再生ドロー溶液として膜モジュール７１１に供給される。再生ドロー溶液のドロー濃度は、例えば６０～９５％である。一方、希釈ドロー溶液から分離された水リッチ溶液は、熱交換器７１３を介して最終処理ユニット７１６に供給される。水リッチ溶液は例えば、水が９９％、ドロー濃度が１％である。 (Water separation process)
In the separation tank 715, a water separation step is performed. That is, in the separation tank 715, the diluted draw solution is separated into a water-rich solution containing a large amount of water and a concentrated regenerated draw solution containing a high concentration of polymer. The pressure in the separation tank 715 is atmospheric pressure. The phase separation between the water-rich solution and the regenerated draw solution can be performed by allowing the solution to stand at a liquid temperature equal to or higher than the cloud point. In the first apparatus example, the liquid temperature is, for example, 88 ° C., which is equal to or higher than the cloud point and 100 ° C. or lower. The draw solution separated from the diluted draw solution and concentrated is supplied to the membrane module 711 as a regenerated draw solution. The draw concentration of the regenerated draw solution is, for example, 60 to 95%. On the other hand, the water-rich solution separated from the diluted draw solution is supplied to the final processing unit 716 via the heat exchanger 713. The water-rich solution is, for example, 99% water and 1% draw concentration.
　（流出側熱交換工程）
　流出側熱交換手段としての熱交換器７１３においては、流出側熱交換工程が行われる。すなわち、膜モジュール７１１から流出した希釈ドロー溶液は、まず、熱交換器７１３に供給される。一方、熱交換器７１３には、分離槽７１５において得られた水リッチ溶液が供給される。第１装置例においては、熱交換器７１３によって、水リッチ溶液を所定温度、具体的に例えば４５℃程度の温度に調整する。上述したように、分離槽７１５においては液温が曇点以上１００℃以下で水分離工程が行われる。そのため、分離槽７１５から流出する水リッチ溶液は、熱交換器７１２において降温された後に膜モジュール７１１から流出する希釈ドロー溶液よりも高温である。一方、後段の最終処理ユニット７１６における処理温度は、例えば２０℃以上５０℃以下、好適には３５℃以上４５℃以下、第１装置例においては、例えば４５℃である。そこで、熱交換器７１３において、水リッチ溶液を所定温度まで降温させる温度調整が行われる。すなわち、熱交換器７１３において、水リッチ溶液は希釈ドロー溶液によって冷却される一方、希釈ドロー溶液は水リッチ溶液によって加熱される。 (Outflow side heat exchange process)
In the heat exchanger 713 as the outflow side heat exchange means, the outflow side heat exchange step is performed. That is, the diluted draw solution flowing out of the membrane module 711 is first supplied to the heat exchanger 713. On the other hand, the water-rich solution obtained in the separation tank 715 is supplied to the heat exchanger 713. In the first device example, the water-rich solution is adjusted to a predetermined temperature, specifically, for example, about 45 ° C. by the heat exchanger 713. As described above, in the separation tank 715, the water separation step is performed when the liquid temperature is above the cloud point and below 100 ° C. Therefore, the water-rich solution flowing out of the separation tank 715 is hotter than the diluted draw solution flowing out of the membrane module 711 after being cooled in the heat exchanger 712. On the other hand, the processing temperature in the final processing unit 716 in the subsequent stage is, for example, 20 ° C. or higher and 50 ° C. or lower, preferably 35 ° C. or higher and 45 ° C. or lower, and in the first apparatus example, for example, 45 ° C. Therefore, in the heat exchanger 713, the temperature is adjusted to lower the temperature of the water-rich solution to a predetermined temperature. That is, in the heat exchanger 713, the water-rich solution is cooled by the diluted draw solution, while the diluted draw solution is heated by the water-rich solution.
　（最終処理工程）
　最終処理ユニット７１６においては、分離処理工程としての最終処理工程が行われる。すなわち、分離槽７１５において分離された水リッチ溶液においては、ポリマーが残存している可能性がある。そこで、最終処理ユニット７１６において、水リッチ溶液から分離処理ドロー溶液となるポリマー溶液を分離することによって、淡水などの透過水が得られる。 (Final processing process)
In the final processing unit 716, a final processing step as a separation processing step is performed. That is, the polymer may remain in the water-rich solution separated in the separation tank 715. Therefore, in the final treatment unit 716, permeated water such as fresh water can be obtained by separating the polymer solution to be the separation treatment draw solution from the water-rich solution.
　水リッチ溶液から分離された透過水は、含水溶液から得られた最終生成物として、外部の必要な用途に供給される。なお、最終処理ユニット７１６において、透過水と分離されたドロー溶液は、ドロー濃度が０．５～２５％程度のポリマー溶液であり、外部に廃棄されるか、少なくとも加熱器７１４または熱交換器７１３の上流側における希釈ドロー溶液に導入される。また、透過水と分離されたポリマー溶液の一部を廃棄し、残りのポリマー溶液を少なくとも加熱器７１４の上流側または熱交換器７１３の上流側における希釈ドロー溶液に導入することも可能である。 The permeated water separated from the water-rich solution is supplied to the required external applications as the final product obtained from the aqueous solution. In the final treatment unit 716, the draw solution separated from the permeated water is a polymer solution having a draw concentration of about 0.5 to 25%, and is discarded to the outside, or at least the heater 714 or the heat exchanger 713. It is introduced into the diluted draw solution on the upstream side of. It is also possible to discard part of the polymer solution separated from the permeated water and introduce the remaining polymer solution into a diluted draw solution at least upstream of the heater 714 or upstream of the heat exchanger 713.
　（第１装置実施例）
　次に、以上のように構成された正浸透装置７１の第１装置実施例について説明する。なお、第１装置実施例においては、正浸透装置７１を用いて、流量が１００Ｌ／ｈの含水溶液（濃縮水）から流量が６７Ｌ／ｈの淡水（透過水）を生成する場合を例に説明する。 (Example of the first apparatus)
Next, a first device embodiment of the forward osmosis device 71 configured as described above will be described. In the first embodiment, a case where the forward osmosis device 71 is used to generate fresh water (permeated water) having a flow rate of 67 L / h from an aqueous solution (concentrated water) having a flow rate of 100 L / h will be described as an example. do.
　第１装置実施例においては、正浸透装置７１に外部から導入された濃縮水に対して熱交換器７１２によって熱交換を行い、４０℃の温度の濃縮水を膜モジュール７１１に供給する。膜モジュール７１１によって濃縮された濃縮水は、３３Ｌ／ｈの流量で膜モジュール７１１から排出される。すなわち、膜モジュール７１１において、６７Ｌ／ｈの流量で水の移動が行われる。 In the first embodiment, heat exchange is performed with the concentrated water introduced from the outside into the forward osmosis apparatus 71 by the heat exchanger 712, and the concentrated water having a temperature of 40 ° C. is supplied to the membrane module 711. The concentrated water concentrated by the membrane module 711 is discharged from the membrane module 711 at a flow rate of 33 L / h. That is, in the membrane module 711, water is moved at a flow rate of 67 L / h.
　一方、熱交換器７１２において濃縮水によって熱交換された４０℃の温度の再生ドロー溶液は、膜モジュール７１１に供給されて希釈され、希釈ドロー溶液として流出する。ここで、再生ドロー溶液の流量は１００Ｌ／ｈである。膜モジュール７１１から流出される希釈ドロー溶液の温度は、４０℃であり、流量は１６７Ｌ／ｈである。その後、希釈ドロー溶液は、熱交換器７１３において８８℃の水リッチ溶液と熱交換されて加熱され、４０℃から５２℃の温度まで昇温された後、加熱器７１４に供給されてさらに加熱され、５２℃から８８℃の温度まで昇温される。希釈ドロー溶液は、分離槽７１５に供給されて、再生ドロー溶液と水リッチ溶液とに相分離される。 On the other hand, the regenerated draw solution having a temperature of 40 ° C., which has been heat-exchanged with concentrated water in the heat exchanger 712, is supplied to the membrane module 711, diluted, and flows out as a diluted draw solution. Here, the flow rate of the regenerated draw solution is 100 L / h. The temperature of the diluted draw solution flowing out of the membrane module 711 is 40 ° C., and the flow rate is 167 L / h. Then, the diluted draw solution is heated by heat exchange with a water-rich solution at 88 ° C. in the heat exchanger 713, heated to a temperature of 40 ° C. to 52 ° C., and then supplied to the heater 714 to be further heated. , The temperature is raised from 52 ° C. to 88 ° C. The diluted draw solution is supplied to the separation tank 715 and phase-separated into the regenerated draw solution and the water-rich solution.
　再生ドロー溶液は、温度が８８℃、流量が１００Ｌ／ｈである。水リッチ溶液は、温度が８８℃、流量が６７Ｌ／ｈである。再生ドロー溶液は、熱交換器７１２に供給されて低温の含水溶液と熱交換されて、８８℃から４０℃まで降温される。 The regenerated draw solution has a temperature of 88 ° C. and a flow rate of 100 L / h. The water-rich solution has a temperature of 88 ° C. and a flow rate of 67 L / h. The regenerated draw solution is supplied to the heat exchanger 712 and heat-exchanged with a low-temperature aqueous solution to lower the temperature from 88 ° C. to 40 ° C.
　水リッチ溶液は、熱交換器７１３に供給されて４０℃の希釈ドロー溶液と熱交換されて、８８℃から４５℃まで降温された後に、最終処理ユニット７１６に供給される。最終処理ユニット７１６においては、６７Ｌ／ｈの流量で透過水が得られる。なお、最終処理ユニット７１６において、透過水から分離されるドロー溶液については、少量であることから考慮していない。以上により、１００Ｌ／ｈの流量の濃縮水から、６７Ｌ／ｈの流量の透過水が得られる。 The water-rich solution is supplied to the heat exchanger 713, heat-exchanged with the diluted draw solution at 40 ° C., cooled from 88 ° C. to 45 ° C., and then supplied to the final treatment unit 716. In the final treatment unit 716, permeated water is obtained at a flow rate of 67 L / h. In the final treatment unit 716, the draw solution separated from the permeated water is not considered because it is a small amount. As described above, permeated water having a flow rate of 67 L / h can be obtained from the concentrated water having a flow rate of 100 L / h.
　以上説明したように第１装置例によれば、外部から流入する濃縮水などの含水溶液を用いて、膜モジュール７１１に供給する再生ドロー溶液を所望の温度に調整している。これにより、膜モジュール７１１において含水溶液およびドロー溶液の温度を近い温度にできるので、膜モジュール７１１における処理を安定させることができる。また、分離槽７１５から流出した高温の水リッチ溶液を用いて、膜モジュール７１１から流出した希釈ドロー溶液を昇温させた後に、加熱器７１４によって分離槽７１５に供給する希釈ドロー溶液を曇点以上１００℃以下の温度に加熱している。これにより、加熱器７１４によって希釈ドロー溶液を加熱する際に昇温させる温度幅を小さくできるので、加熱器７１４による加熱に必要なエネルギーを低減でき、正浸透装置７１において、加熱に消費するエネルギーを低減できる。さらに、希釈ドロー溶液を２つの流路に分岐させることなく、熱交換によって希釈ドロー溶液および再生ドロー溶液の温度調整を行っている。これにより、流路における流量のバランスを容易に調整できるので、配管構造を簡素にしつつ、冷却や加熱に要する消費エネルギーを抑制して、エネルギーの収支を安定化できる。 As described above, according to the example of the first apparatus, the regenerated draw solution supplied to the membrane module 711 is adjusted to a desired temperature by using an aqueous solution containing concentrated water or the like flowing from the outside. As a result, the temperatures of the aqueous solution and the draw solution in the membrane module 711 can be brought close to each other, so that the processing in the membrane module 711 can be stabilized. Further, after raising the temperature of the diluted draw solution flowing out from the membrane module 711 using the high-temperature water-rich solution flowing out from the separation tank 715, the diluted draw solution supplied to the separation tank 715 by the heater 714 is above the cloud point. It is heated to a temperature of 100 ° C. or lower. As a result, the temperature range for raising the temperature when the diluted draw solution is heated by the heater 714 can be reduced, so that the energy required for heating by the heater 714 can be reduced, and the energy consumed for heating in the forward osmosis device 71 can be reduced. Can be reduced. Further, the temperature of the diluted draw solution and the regenerated draw solution is adjusted by heat exchange without branching the diluted draw solution into two flow paths. As a result, the balance of the flow rate in the flow path can be easily adjusted, so that the energy balance can be stabilized by suppressing the energy consumption required for cooling and heating while simplifying the piping structure.
　（第２装置例）
　（正浸透装置および正浸透処理工程）
　まず、本発明の実施形態による水処理装置１～８の正浸透装置７０の第２装置例について説明する。図１５は、第２装置例による正浸透装置を模式的に示すブロック図である。図１５に示すように、第２装置例による正浸透装置７２は、内部に半透膜７２１ａが設けられた膜モジュール７２１、熱交換器７２２，７２３，７２４、加熱器７２５、分離槽７２６、および最終処理ユニット７２７を備えて構成される。正浸透装置７２における、膜モジュール７２１、半透膜７２１ａ、熱交換器７２２，７２３、加熱器７２５、分離槽７２６、および最終処理ユニット７２７はそれぞれ、第１装置例による正浸透装置７１における、膜モジュール７１１、半透膜７１１ａ、熱交換器７１２，７１３、加熱器７１４、分離槽７１５、および最終処理ユニット７１６と同様である。 (Example of second device)
(Forward osmosis device and forward osmosis treatment process)
First, a second device example of the forward osmosis device 70 of the water treatment devices 1 to 8 according to the embodiment of the present invention will be described. FIG. 15 is a block diagram schematically showing a forward osmosis device according to the second device example. As shown in FIG. 15, the forward osmosis device 72 according to the second device example includes a membrane module 721 having a semipermeable membrane 721a inside, a heat exchanger 722,723,724, a heater 725, a separation tank 726, and a separation tank 726. It is configured to include a final processing unit 727. The membrane module 721, the semipermeable membrane 721a, the heat exchanger 722, 723, the heater 725, the separation tank 726, and the final processing unit 727 in the forward osmosis apparatus 72 are the membranes in the forward osmosis apparatus 71 according to the first apparatus example, respectively. This is the same as the module 711, the semipermeable membrane 711a, the heat exchangers 712 and 713, the heater 714, the separation tank 715, and the final processing unit 716.
　第２装置例による正浸透装置７２においては、第１装置例と異なり、希釈ドロー溶液の流れ方向に沿った熱交換器７２３の下流側で加熱器７２５の上流側、かつ再生ドロー溶液の流れ方向に沿った分離槽７２６の下流側で熱交換器７２２の上流側に、熱交換器７２４が設けられている。中間熱交換手段としての熱交換器７２４によって、中間熱交換工程が行われる。すなわち、第２装置例による正浸透処理工程においては、膜モジュール７２１から流出した希釈ドロー溶液は、熱交換器７２３において高温の水リッチ溶液との間で熱交換が行われて昇温された後に、さらに熱交換器７２４において水リッチ溶液と同程度の温度の再生ドロー溶液との間で熱交換が行われて昇温される。その後、加熱器７２５によって、希釈ドロー溶液は、曇点以上１００℃以下の温度にまで加熱される。その他の構成は、第１装置例と同様である。 In the normal permeation device 72 according to the second device example, unlike the first device example, the flow direction of the regenerated draw solution is on the downstream side of the heat exchanger 723 along the flow direction of the diluted draw solution and on the upstream side of the heater 725. A heat exchanger 724 is provided on the downstream side of the separation tank 726 and on the upstream side of the heat exchanger 722 along the above. The intermediate heat exchange step is performed by the heat exchanger 724 as the intermediate heat exchange means. That is, in the forward osmosis treatment step according to the second apparatus example, the diluted draw solution flowing out from the membrane module 721 is heated by heat exchange with the high-temperature water-rich solution in the heat exchanger 723. Further, in the heat exchanger 724, heat is exchanged between the water-rich solution and the regenerated draw solution having a temperature similar to that of the water-rich solution, and the temperature is raised. Then, the diluted draw solution is heated to a temperature above the cloud point and below 100 ° C. by the heater 725. Other configurations are the same as those of the first apparatus example.
　（第２装置実施例）
　第２装置実施例においては、正浸透装置７２に外部から導入された濃縮水に対して熱交換器７２２によって熱交換を行い、４０℃の温度の濃縮水を膜モジュール７２１に供給する。膜モジュール７２１によって濃縮された濃縮水は、３３Ｌ／ｈの流量で膜モジュール７２１から排出される。すなわち、膜モジュール７２１において、６７Ｌ／ｈの流量で水の移動が行われる。 (Example of the second device)
In the second embodiment, heat exchange is performed with the concentrated water introduced from the outside into the forward osmosis apparatus 72 by the heat exchanger 722, and the concentrated water having a temperature of 40 ° C. is supplied to the membrane module 721. The concentrated water concentrated by the membrane module 721 is discharged from the membrane module 721 at a flow rate of 33 L / h. That is, in the membrane module 721, water is moved at a flow rate of 67 L / h.
　一方、熱交換器７２２において濃縮水によって熱交換された４０℃の温度の再生ドロー溶液は、膜モジュール７２１に供給されて希釈され、希釈ドロー溶液として流出する。ここで、再生ドロー溶液の流量は１００Ｌ／ｈである。膜モジュール７２１から流出される希釈ドロー溶液は、温度が４０℃、流量が１６７Ｌ／ｈである。その後、希釈ドロー溶液は、熱交換器７２３によって加熱されて５２℃の温度まで昇温された後、熱交換器７２４に供給される。 On the other hand, the regenerated draw solution having a temperature of 40 ° C., which has been heat-exchanged with concentrated water in the heat exchanger 722, is supplied to the membrane module 721, diluted, and flows out as a diluted draw solution. Here, the flow rate of the regenerated draw solution is 100 L / h. The diluted draw solution flowing out of the membrane module 721 has a temperature of 40 ° C. and a flow rate of 167 L / h. The diluted draw solution is then heated by the heat exchanger 723 to a temperature of 52 ° C. and then supplied to the heat exchanger 724.
　希釈ドロー溶液は、熱交換器７２４によって８８℃の再生ドロー溶液と熱交換されて加熱され、５２℃から７１℃の温度まで昇温された後、加熱器７２５に供給されてさらに加熱され、７１℃から８８℃の温度まで昇温される。希釈ドロー溶液は、分離槽７２６に供給されて、再生ドロー溶液と水リッチ溶液とに相分離される。 The diluted draw solution is heated by heat exchange with the regenerated draw solution at 88 ° C. by the heat exchanger 724, heated to a temperature of 52 ° C. to 71 ° C., and then supplied to the heater 725 for further heating. The temperature is raised from ° C to 88 ° C. The diluted draw solution is supplied to the separation tank 726 and phase-separated into the regenerated draw solution and the water-rich solution.
　再生ドロー溶液は、温度が８８℃、流量が１００Ｌ／ｈである。水リッチ溶液は、温度が８８℃、流量が６７Ｌ／ｈである。再生ドロー溶液は、熱交換器７２４により８８℃から６３．５℃まで降温された後、熱交換器７２２により６３．５℃から４０℃まで降温される。 The regenerated draw solution has a temperature of 88 ° C. and a flow rate of 100 L / h. The water-rich solution has a temperature of 88 ° C. and a flow rate of 67 L / h. The regenerated draw solution is cooled from 88 ° C. to 63.5 ° C. by the heat exchanger 724 and then from 63.5 ° C. to 40 ° C. by the heat exchanger 722.
　水リッチ溶液は、熱交換器７２３によって８８℃から４５℃まで降温された後に、最終処理ユニット７２７に供給される。最終処理ユニット７２７においては、６７Ｌ／ｈの流量で透過水が得られる。なお、最終処理ユニット７２７において、透過水から分離されるドロー溶液については、少量であることから考慮していない。以上により、１００Ｌ／ｈの流量の濃縮水から、６７Ｌ／ｈの流量の透過水が得られる。 The water-rich solution is supplied to the final treatment unit 727 after being cooled from 88 ° C. to 45 ° C. by the heat exchanger 723. In the final treatment unit 727, permeated water is obtained at a flow rate of 67 L / h. In the final treatment unit 727, the draw solution separated from the permeated water is not considered because it is a small amount. As described above, permeated water having a flow rate of 67 L / h can be obtained from the concentrated water having a flow rate of 100 L / h.
　以上説明した第２装置例によれば、熱交換器７２２，７２３によって熱交換を行っていることにより、第１装置例と同様の効果を得ることができる。また、熱交換器７２４によって、膜モジュール７２１に供給するための再生ドロー溶液の温度を降温させつつ、分離槽７２６に供給するための希釈ドロー溶液の温度を昇温させていることにより、加熱器７２５によって希釈ドロー溶液を加熱する際に昇温させる温度幅をさらに小さくできる。したがって、加熱器７２５による加熱に必要なエネルギーをさらに低減でき、正浸透装置７２において、加熱に消費するエネルギーをより一層低減できる。 According to the second device example described above, the same effect as that of the first device example can be obtained by performing heat exchange by the heat exchangers 722 and 723. Further, the heat exchanger 724 lowers the temperature of the regenerated draw solution to be supplied to the membrane module 721 while raising the temperature of the diluted draw solution to be supplied to the separation tank 726. With 725, the temperature range for raising the temperature when heating the diluted draw solution can be further reduced. Therefore, the energy required for heating by the heater 725 can be further reduced, and the energy consumed for heating in the forward osmosis apparatus 72 can be further reduced.
　（第３装置例）
　（正浸透装置および正浸透処理工程）
　次に、本発明の第３装置例について説明する。図１５は、第３装置例による正浸透装置７３を示す。図１５に示すように、第３装置例による正浸透装置７３は、内部に半透膜７３１ａが設けられた膜モジュール７３１、熱交換器７３２，７３３，７３４、加熱器７３５、分離槽７３６、および最終処理ユニット７３７を備えて構成される。正浸透装置７３における、膜モジュール７３１、半透膜７３１ａ、熱交換器７３２，７３３、加熱器７３５、分離槽７３６、および最終処理ユニット７３７はそれぞれ、第１装置例による正浸透装置７１における、膜モジュール７１１、半透膜７１１ａ、熱交換器７１２，７１３、加熱器７１４、分離槽７１５、および最終処理ユニット７１６と同様である。 (Example of third device)
(Forward osmosis device and forward osmosis treatment process)
Next, an example of the third device of the present invention will be described. FIG. 15 shows a forward osmosis device 73 according to the third device example. As shown in FIG. 15, the forward osmosis device 73 according to the third device example includes a membrane module 731 having a semipermeable membrane 731a inside, a heat exchanger 732, 733, 734, a heater 735, a separation tank 736, and a separation tank 736. It is configured to include a final processing unit 737. The membrane module 731, the semipermeable membrane 731a, the heat exchanger 732, 733, the heater 735, the separation tank 736, and the final processing unit 737 in the forward osmosis apparatus 73 are the membranes in the forward osmosis apparatus 71 according to the first apparatus example, respectively. This is the same as the module 711, the semipermeable membrane 711a, the heat exchangers 712 and 713, the heater 714, the separation tank 715, and the final processing unit 716.
　第３装置例による正浸透装置７３においては、第１装置例と異なり、希釈ドロー溶液の流れ方向に沿った膜モジュール７３１の下流側で熱交換器７３３の上流側、かつ再生ドロー溶液の流れ方向に沿った分離槽７３６の下流側で熱交換器７３２の上流側に、熱交換器７３４が設けられている。前段熱交換手段としての熱交換器７３４によって、前段熱交換工程が行われる。すなわち、第３装置例による正浸透処理工程においては、膜モジュール７３１から流出した希釈ドロー溶液は、まず、熱交換器７３４において分離槽７３６から供給された高温の再生ドロー溶液との間で熱交換が行われて昇温される。続けて、さらに熱交換器７３３において分離槽７３６から供給された高温の水リッチ溶液との間で熱交換が行われて昇温される。その後、加熱器７３５によって、希釈ドロー溶液は、曇点以上１００℃以下の温度にまで加熱される。その他の構成は、第１装置例と同様である。 In the forward osmosis apparatus 73 according to the third apparatus example, unlike the first apparatus example, the downstream side of the membrane module 731 along the flow direction of the diluted draw solution, the upstream side of the heat exchanger 733, and the flow direction of the regenerated draw solution. A heat exchanger 734 is provided on the downstream side of the separation tank 736 and on the upstream side of the heat exchanger 732 along the above. The pre-stage heat exchange step is performed by the heat exchanger 734 as the pre-stage heat exchange means. That is, in the forward osmosis treatment step according to the third apparatus example, the diluted draw solution flowing out from the membrane module 731 first exchanges heat with the high-temperature regenerated draw solution supplied from the separation tank 736 in the heat exchanger 734. Is performed and the temperature is raised. Subsequently, heat exchange is further performed with the high-temperature water-rich solution supplied from the separation tank 736 in the heat exchanger 733 to raise the temperature. Then, the diluted draw solution is heated to a temperature above the cloud point and below 100 ° C. by the heater 735. Other configurations are the same as those of the first apparatus example.
　（第３装置実施例）
　第３装置実施例においては、正浸透装置７３に外部から導入された濃縮水に対して熱交換器７３２によって熱交換を行い、４０℃の温度の濃縮水を膜モジュール７３１に供給する。膜モジュール７３１によって濃縮された濃縮水は、３３Ｌ／ｈの流量で膜モジュール７３１から排出される。すなわち、膜モジュール７３１において、６７Ｌ／ｈの流量で水の移動が行われる。 (Example of the third device)
In the third apparatus embodiment, the concentrated water introduced from the outside into the forward osmosis apparatus 73 is heat-exchanged by the heat exchanger 732, and the concentrated water having a temperature of 40 ° C. is supplied to the membrane module 731. The concentrated water concentrated by the membrane module 731 is discharged from the membrane module 731 at a flow rate of 33 L / h. That is, in the membrane module 731, water is moved at a flow rate of 67 L / h.
　一方、熱交換器７３２において濃縮水によって熱交換された４０℃の温度の再生ドロー溶液は、膜モジュール７３１に供給されて希釈され、希釈ドロー溶液として流出する。ここで、再生ドロー溶液の流量は１００Ｌ／ｈである。膜モジュール７３１から流出される希釈ドロー溶液は、温度が４０℃、流量が１６７Ｌ／ｈである。 On the other hand, the regenerated draw solution having a temperature of 40 ° C., which has been heat-exchanged with concentrated water in the heat exchanger 732, is supplied to the membrane module 731, diluted, and flows out as a diluted draw solution. Here, the flow rate of the regenerated draw solution is 100 L / h. The diluted draw solution flowing out of the membrane module 731 has a temperature of 40 ° C. and a flow rate of 167 L / h.
　その後、希釈ドロー溶液は、熱交換器７３４において分離槽７３６から供給された８８℃の再生ドロー溶液と熱交換を行って加熱されて５２℃の温度まで昇温された後、熱交換器７３３に供給される。希釈ドロー溶液は、熱交換器７３３において分離槽７３６から供給された８８℃の水リッチ溶液と熱交換されて６１℃の温度まで昇温された後、加熱器７３５に供給されてさらに加熱され、６１℃から８８℃の温度まで昇温される。希釈ドロー溶液は、分離槽７３６に供給されて、再生ドロー溶液と水リッチ溶液とに相分離される。 Then, the diluted draw solution is heated by heat exchange with the 88 ° C. regenerated draw solution supplied from the separation tank 736 in the heat exchanger 734 to raise the temperature to 52 ° C., and then into the heat exchanger 733. Be supplied. The diluted draw solution is heat-exchanged with the water-rich solution at 88 ° C. supplied from the separation tank 736 in the heat exchanger 733 to be heated to a temperature of 61 ° C., and then supplied to the heater 735 to be further heated. The temperature is raised from 61 ° C to 88 ° C. The diluted draw solution is supplied to the separation tank 736 and phase-separated into the regenerated draw solution and the water-rich solution.
　再生ドロー溶液は、温度が８８℃、流量が１００Ｌ／ｈである。水リッチ溶液は、温度が８８℃、流量が６７Ｌ／ｈである。再生ドロー溶液は、熱交換器７３４により８８℃から７２．４℃まで降温された後、熱交換器７３２により７２．４℃から４０℃まで降温される。 The regenerated draw solution has a temperature of 88 ° C. and a flow rate of 100 L / h. The water-rich solution has a temperature of 88 ° C. and a flow rate of 67 L / h. The regenerated draw solution is cooled from 88 ° C. to 72.4 ° C. by the heat exchanger 734 and then from 72.4 ° C. to 40 ° C. by the heat exchanger 732.
　水リッチ溶液は、熱交換器７３３によって８８℃から５７℃まで降温された後に、最終処理ユニット７３７に供給される。なお、最終処理ユニット７３７として膜処理装置を用いる場合などのように、最終処理ユニット７３７における耐熱性が低い場合には、熱交換器７３３と最終処理ユニット７３７との間に、さらに冷却手段（図示せず）を設置することによって、水リッチ溶液を所定の温度まで冷却しても良い。 The water-rich solution is supplied to the final treatment unit 737 after being cooled from 88 ° C. to 57 ° C. by the heat exchanger 733. When the heat resistance of the final treatment unit 737 is low, such as when a membrane treatment device is used as the final treatment unit 737, further cooling means (FIG. 6) is provided between the heat exchanger 733 and the final treatment unit 737. The water-rich solution may be cooled to a predetermined temperature by installing (not shown).
　最終処理ユニット７３７においては、６７Ｌ／ｈの流量で透過水が得られる。なお、最終処理ユニット７３７において、透過水から分離されるドロー溶液については、少量であることから考慮していない。以上により、１００Ｌ／ｈの流量の濃縮水から、６７Ｌ／ｈの流量の透過水が得られる。 In the final treatment unit 737, permeated water can be obtained at a flow rate of 67 L / h. In the final treatment unit 737, the draw solution separated from the permeated water is not considered because it is a small amount. As described above, permeated water having a flow rate of 67 L / h can be obtained from the concentrated water having a flow rate of 100 L / h.
　以上説明したように第３装置例によれば、熱交換器７３２，７３３によって熱交換を行っていることにより、第１装置例と同様の効果を得ることができる。また、熱交換器７３４によって、膜モジュール７３１に供給するための再生ドロー溶液の温度を降温させつつ、希釈ドロー溶液の温度を昇温させていることにより、第２装置例と同様の効果を得ることができる。 As described above, according to the third device example, the same effect as that of the first device example can be obtained by performing heat exchange by the heat exchangers 732 and 733. Further, the heat exchanger 734 lowers the temperature of the regenerated draw solution for supplying to the membrane module 731 while raising the temperature of the diluted draw solution, thereby obtaining the same effect as that of the second apparatus example. be able to.
　（第４装置例）
　（正浸透装置および正浸透処理工程）
　次に、本発明の第４装置例による正浸透装置について説明する。図１７は、第４装置例による正浸透装置７４を模式的に示すブロック図である。図１７に示すように、第４装置例による正浸透装置７４は、半透膜７４１ａを有する膜モジュール７４１、熱交換器７４２ａ，７４２ｂ，７４２ｃ、前処理ユニット７４３、加熱器７４４、分離槽７４５、最終処理ユニット７４６、温度計７４７ａ，７４７ｂ、流量計７４８、調節弁７４９ａ，７４９ｂ、および制御部７５０を備えて構成される。正浸透装置７４における、膜モジュール７４１、半透膜７４１ａ、熱交換器７４２ａ，７４２ｂ，７４２ｃ、加熱器７４４、分離槽７４５、および最終処理ユニット７４６はそれぞれ、第２装置例による正浸透装置７２における、膜モジュール７２１、半透膜７２１ａ、熱交換器７２２，７２３，７２４、加熱器７２５、分離槽７２６、および最終処理ユニット７２７と同様である。 (Example of 4th device)
(Forward osmosis device and forward osmosis treatment process)
Next, the forward osmosis apparatus according to the fourth apparatus example of the present invention will be described. FIG. 17 is a block diagram schematically showing the forward osmosis device 74 according to the fourth device example. As shown in FIG. 17, the forward osmosis device 74 according to the fourth device example includes a membrane module 741 having a semipermeable membrane 741a, heat exchangers 742a, 742b, 742c, a pretreatment unit 743, a heater 744, and a separation tank 745. It includes a final processing unit 746, thermometers 747a and 747b, a flow meter 748, control valves 749a and 749b, and a control unit 750. The membrane module 741, the semipermeable membrane 741a, the heat exchangers 742a, 742b, 742c, the heater 744, the separation tank 745, and the final processing unit 746 in the forward osmosis apparatus 74 are each in the forward osmosis apparatus 72 according to the second apparatus example. , Membrane module 721, semipermeable membrane 721a, heat exchanger 722,723,724, heater 725, separation tank 726, and final treatment unit 727.
　前処理手段としての前処理ユニット７４３は、含水溶液の流れ方向に沿って、膜モジュール７４１の上流側に設けられる。前処理ユニット７４３は、外部から供給される含水溶液を膜モジュール７４１に導入する前に、含水溶液に含まれる濁質などの不純物を除去する処理を行う。前処理ユニット７４３としては、砂ろ過や、ＭＦ膜またはＵＦ膜などの前処理膜など、従来公知の前処理装置を採用することができる。 The pretreatment unit 743 as the pretreatment means is provided on the upstream side of the membrane module 741 along the flow direction of the aqueous solution. The pretreatment unit 743 performs a treatment for removing impurities such as turbidity contained in the aqueous solution before introducing the aqueous solution supplied from the outside into the membrane module 741. As the pretreatment unit 743, a conventionally known pretreatment device such as sand filtration or a pretreatment membrane such as an MF membrane or a UF membrane can be adopted.
　熱交換器７４２ａは、膜モジュール７４１に対して含水溶液の流れ方向に沿った上流側、かつ分離槽７４５から流出されて再利用される再生ドロー溶液の流れ方向に沿った分離槽７４５の下流側に設けられる。熱交換器７４２ａは、分離槽７４５から流出される再生ドロー溶液と外部から供給される含水溶液との間で熱交換を行う。 The heat exchanger 742a is located on the upstream side of the membrane module 741 along the flow direction of the aqueous solution, and on the downstream side of the separation tank 745 along the flow direction of the regenerated draw solution that is discharged from the separation tank 745 and reused. It is provided in. The heat exchanger 742a exchanges heat between the regenerated draw solution flowing out of the separation tank 745 and the aqueous solution containing water supplied from the outside.
　含水溶液温度計測手段としての温度計７４７ａは、膜モジュール７４１に対して含水溶液の流れ方向に沿った少なくとも上流側、第４装置例においては、前処理ユニット７４３の上流側かつ熱交換器７４２ａの下流側に設けられる。温度計７４７ａは、熱交換器７４２ａによって熱交換された含水溶液の温度を計測し、温度の計測値を制御部７５０に供給する。 The thermometer 747a as the aqueous solution temperature measuring means is at least upstream of the film module 741 along the flow direction of the aqueous solution, and in the fourth apparatus example, upstream of the pretreatment unit 743 and the heat exchanger 742a. It is provided on the downstream side. The thermometer 747a measures the temperature of the aqueous solution containing heat exchanged by the heat exchanger 742a, and supplies the measured value of the temperature to the control unit 750.
　ドロー溶液温度計測手段としての温度計７４７ｂは、膜モジュール７４１に対して、再生ドロー溶液の流れ方向に沿った少なくとも上流側、かつ再生ドロー溶液の流れ方向に沿った熱交換器７４２ａの下流側に設けられる。温度計７４７ｂは、熱交換器７４２ａによって熱交換された再生ドロー溶液の温度を計測し、温度の計測値を制御部７５０に供給する。 The thermometer 747b as the draw solution temperature measuring means is at least upstream of the membrane module 741 along the flow direction of the regenerated draw solution and downstream of the heat exchanger 742a along the flow direction of the regenerated draw solution. Provided. The thermometer 747b measures the temperature of the regenerated draw solution heat-exchanged by the heat exchanger 742a, and supplies the measured value of the temperature to the control unit 750.
　流量計測手段としての流量計７４８は、膜モジュール７４１に対して含水溶液の流れ方向に沿った少なくとも上流側に設けられる。流量計７４８は、膜モジュール７４１に流入する含水溶液の流量を計測し、流量の計測値を制御部７５０に供給する。 The flow meter 748 as a flow rate measuring means is provided at least on the upstream side of the membrane module 741 along the flow direction of the aqueous solution. The flow meter 748 measures the flow rate of the aqueous solution containing water flowing into the membrane module 741 and supplies the measured value of the flow rate to the control unit 750.
　調節弁７４９ａは、膜モジュール７４１に対して含水溶液の流れ方向に沿った少なくとも上流側、第４装置例においては、前処理ユニット７４３の上流側かつ熱交換器７４２ａの下流側に設けられる。調節弁７４９ａは、前処理ユニット７４３に流入する含水溶液の流量、ひいては膜モジュール７４１に流入する含水溶液の流量を調整するための正浸透流量調節手段である。調節弁７４９ａは、流量計７４８による含水溶液の流量の計測値や、温度計７４７ａ，７４７ｂによる温度の計測値に基づいて、制御部７５０によって開度が制御される。具体的に、前処理ユニット７４３に流入する含水溶液の流量が一定になって、膜モジュール７４１に流入する含水溶液の流量が一定になるように、制御部７５０によって調節弁７４９ａの開度が調整される。 The control valve 749a is provided at least on the upstream side of the membrane module 741 along the flow direction of the aqueous solution, on the upstream side of the pretreatment unit 743 and on the downstream side of the heat exchanger 742a in the fourth device example. The control valve 749a is a forward osmosis flow rate adjusting means for adjusting the flow rate of the aqueous solution flowing into the pretreatment unit 743 and the flow rate of the aqueous solution flowing into the membrane module 741. The opening degree of the control valve 749a is controlled by the control unit 750 based on the measured value of the flow rate of the aqueous solution contained by the flow meter 748 and the measured value of the temperature by the thermometers 747a and 747b. Specifically, the opening degree of the control valve 749a is adjusted by the control unit 750 so that the flow rate of the aqueous solution containing water flowing into the pretreatment unit 743 becomes constant and the flow rate of the aqueous solution containing water flowing into the membrane module 741 becomes constant. Will be done.
　熱交換流量調節手段としての調節弁７４９ｂは、バイパス手段としてのバイパス配管に設けられている。バイパス配管は、希釈ドロー溶液の流れ方向に沿って熱交換器７４２ｃの上流側から下流側に連通させて、希釈ドロー溶液を通過可能に構成されている。これにより、調節弁７４９ｂの開度を調整することによって、中間熱交換手段としての熱交換器７４２ｃを通過する希釈ドロー溶液の流量を調節可能に構成される。 The control valve 749b as the heat exchange flow rate adjusting means is provided in the bypass pipe as the bypass means. The bypass pipe is configured to communicate with the heat exchanger 742c from the upstream side to the downstream side along the flow direction of the diluted draw solution so that the diluted draw solution can pass through. Thereby, by adjusting the opening degree of the control valve 749b, the flow rate of the diluted draw solution passing through the heat exchanger 742c as the intermediate heat exchange means can be adjusted.
　すなわち、調節弁７４９ｂの開度が０であって、全閉の場合、膜モジュール７４１から流出した希釈ドロー溶液は全量、熱交換器７４２ｃを通過する。一方、調節弁７４９ｂの開度が最大であって全開の場合、膜モジュール７４１から流出した希釈ドロー溶液は、バイパス配管に流れ得る量だけ調節弁７４９ｂを通過する。この場合、熱交換器７４２ｃを通過する希釈ドロー溶液の流量は最小になる。このように、調節弁７４９ｂの開度に応じて、熱交換器７４２ｃにおいて熱交換される希釈ドロー溶液の流量を調整可能に構成される。これにより、調節弁７４９ｂの開度に応じて、分離槽７４５から流出した再生ドロー溶液の温度を調整することができる。 That is, when the opening degree of the control valve 749b is 0 and the control valve 749b is fully closed, the entire amount of the diluted draw solution flowing out from the membrane module 741 passes through the heat exchanger 742c. On the other hand, when the opening degree of the control valve 749b is maximum and the control valve 749b is fully opened, the diluted draw solution flowing out from the membrane module 741 passes through the control valve 749b in an amount that can flow into the bypass pipe. In this case, the flow rate of the diluted draw solution passing through the heat exchanger 742c is minimized. In this way, the flow rate of the diluted draw solution to be heat-exchanged in the heat exchanger 742c can be adjusted according to the opening degree of the control valve 749b. Thereby, the temperature of the regenerated draw solution flowing out from the separation tank 745 can be adjusted according to the opening degree of the control valve 749b.
　再生ドロー溶液の温度の調整は、温度計７４７ｂにより計測される温度が略一定、具体的に例えば４０℃程度になるように行うことが望ましい。このように、膜モジュール７４１に供給される再生ドロー溶液の温度を所定温度で略一定に維持するように、調節弁７４９ｂの開度を制御することによって，正浸透装置７４の全体において、熱交換効率を向上でき、調節弁７４９ａを通じて行われる含水溶液の廃棄量を削減できるので、ブローダウン水の送水に要するエネルギーを低減できる。 It is desirable to adjust the temperature of the regenerated draw solution so that the temperature measured by the thermometer 747b is substantially constant, specifically, for example, about 40 ° C. In this way, by controlling the opening degree of the control valve 749b so that the temperature of the regenerated draw solution supplied to the membrane module 741 is kept substantially constant at a predetermined temperature, heat exchange is performed in the entire forward osmosis device 74. Since the efficiency can be improved and the amount of waste of the aqueous solution contained through the control valve 749a can be reduced, the energy required for sending the blowdown water can be reduced.
　制御手段としての制御部７５０は、シーケンサーと呼ばれる機器を用いることができる。物理的には、ＣＰＵ（Central　Processing　Unit）、ＲＡＭ（Random　Access　Memory）やＲＯＭ（Read　Only　Memory）およびインターフェースなどを含む周知のマイクロコンピュータを主体とする電子回路である。制御部７５０は、ＲＡＭに入力されたデータおよびあらかじめＲＯＭなどに記憶されているデータを使用して演算を行い、その演算結果を指令信号として出力する。制御部７５０は、ＲＯＭに保持されるプログラムをＲＡＭにロードしてＣＰＵで実行することで、ＣＰＵの制御に基づいて正浸透装置７４の各種装置を動作させるとともに、記録部としてのＲＡＭやＲＯＭにおけるデータの読み出しおよびＲＡＭへの書き込みを行う。制御部７５０は、温度計７４７ａ，７４７ｂおよび流量計７４８から計測値のデータが入力されるとともに、調節弁７４９ａ，７４９ｂの開度を制御する。 The control unit 750 as a control means can use a device called a sequencer. Physically, it is an electronic circuit mainly composed of a well-known microcomputer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an interface. The control unit 750 performs a calculation using the data input to the RAM and the data stored in the ROM or the like in advance, and outputs the calculation result as a command signal. The control unit 750 loads the program held in the ROM into the RAM and executes it in the CPU to operate various devices of the normal penetration device 74 based on the control of the CPU, and also in the RAM or ROM as a recording unit. Reads data and writes to RAM. The control unit 750 inputs the data of the measured values from the thermometers 747a and 747b and the flow meter 748, and controls the opening degree of the control valves 749a and 749b.
　次に、第４装置例による正浸透装置７４を用いた正浸透処理工程について説明する。第４装置例による正浸透処理工程において、正浸透工程、加熱工程、水分離工程、流出側熱交換工程、および最終処理工程は、第１装置実施例と同様である。 Next, the forward osmosis treatment step using the forward osmosis apparatus 74 according to the fourth apparatus example will be described. In the forward osmosis treatment step according to the fourth apparatus example, the forward osmosis step, the heating step, the water separation step, the outflow side heat exchange step, and the final treatment step are the same as those in the first apparatus example.
　（前処理工程）
　前処理手段としての前処理ユニット７４３においては、前処理工程が行われる。すなわち、前処理ユニット７４３においては、外部から供給される含水溶液に対して、含水溶液に含まれる濁質などの不純物を除去する処理が行われる。前処理工程が行われた含水溶液は、膜モジュール７４１に供給される。 (Pretreatment process)
In the pretreatment unit 743 as the pretreatment means, the pretreatment step is performed. That is, in the pretreatment unit 743, a treatment for removing impurities such as turbidity contained in the aqueous solution is performed on the aqueous solution supplied from the outside. The aqueous solution containing the pretreatment step is supplied to the membrane module 741.
　（流入側熱交換工程）
　第４装置例においては、流入側熱交換手段としての熱交換器７４２ａ、調節弁７４９ｂ、および制御部７５０によって、流入側熱交換工程が行われる。すなわち、外部から正浸透装置７４に供給される含水溶液は、まず、熱交換器７４２ａに供給される。一方、熱交換器７４２ａには、分離槽７４５から流出されて熱交換器７４２ｃを通過した再生ドロー溶液が供給される。第４装置例においては、熱交換器７４２ａによって、再生ドロー溶液および含水溶液の温度が所定温度、例えば４０℃程度に調整される。ここで、第４装置例における、含水溶液および再生ドロー溶液の温度を所定温度に調整する流入側熱交換工程について説明する。 (Inflow side heat exchange process)
In the fourth device example, the inflow side heat exchange step is performed by the heat exchanger 742a, the control valve 749b, and the control unit 750 as the inflow side heat exchange means. That is, the aqueous solution contained in the forward osmosis device 74 supplied from the outside is first supplied to the heat exchanger 742a. On the other hand, the heat exchanger 742a is supplied with the regenerated draw solution that has flowed out of the separation tank 745 and passed through the heat exchanger 742c. In the fourth device example, the heat exchanger 742a adjusts the temperatures of the regenerated draw solution and the aqueous solution-containing solution to a predetermined temperature, for example, about 40 ° C. Here, the inflow side heat exchange step of adjusting the temperature of the aqueous solution and the regenerated draw solution to a predetermined temperature in the fourth apparatus example will be described.
　まず、温度計７４７ｂによって、再生ドロー溶液の流れ方向に沿った熱交換器７４２ａの下流側での温度を計測する。計測された温度の計測値は、制御部７５０に供給される。一方、温度計７４７ａによって、含水溶液の流れ方向に沿った熱交換器７４２ａの下流側での温度を計測する。計測された温度の計測値は、制御部７５０に供給される。制御部７５０は、温度計７４７ａ，７４７ｂから供給された計測値と、あらかじめ設定された膜モジュール７４１に供給する際の所定温度とを比較した結果に基づいて、中間熱交換工程を行う希釈ドロー溶液の流量を調節する熱交換流量調節工程を行う。 First, the temperature on the downstream side of the heat exchanger 742a along the flow direction of the regenerated draw solution is measured by a thermometer 747b. The measured value of the measured temperature is supplied to the control unit 750. On the other hand, the thermometer 747a measures the temperature on the downstream side of the heat exchanger 742a along the flow direction of the aqueous solution. The measured value of the measured temperature is supplied to the control unit 750. The control unit 750 performs an intermediate heat exchange step based on the result of comparing the measured values supplied from the thermometers 747a and 747b with the predetermined temperature when the temperature is supplied to the preset membrane module 741. A heat exchange flow rate adjusting step for adjusting the flow rate of the module is performed.
　（熱交換流量調節工程および中間熱交換工程）
　熱交換器７４２ｃにおいては、希釈ドロー溶液と再生ドロー溶液との間で熱交換が行われる中間熱交換工程が行われる。制御部７５０は、温度計７４７ａ，７４７ｂから制御部７５０に供給される温度の計測値に基づいて、調節弁７４９ｂを調整する熱交換流量調整工程を行う。制御部７５０は、必要に応じて、温度計７４７ａ，７４７ｂから制御部７５０に供給される温度の計測値に基づいて調節弁７４９ａを調節する。 (Heat exchange flow rate adjustment process and intermediate heat exchange process)
In the heat exchanger 742c, an intermediate heat exchange step is performed in which heat exchange is performed between the diluted draw solution and the regenerated draw solution. The control unit 750 performs a heat exchange flow rate adjusting step for adjusting the control valve 749b based on the measured values of the temperature supplied from the thermometers 747a and 747b to the control unit 750. The control unit 750 adjusts the control valve 749a based on the measured value of the temperature supplied from the thermometers 747a and 747b to the control unit 750, if necessary.
　すなわち、制御部７５０は、温度計７４７ａ，７４７ｂにより計測される温度が、それぞれ略一定に維持されるように、調節弁７４９ａ，７４９ｂの開度をそれぞれ制御する。また、調節弁７４９ａ，７４９ｂの開度は、制御部７５０によって独立に制御される。以下に、温度計７４７ａ，７４７ｂが計測する温度を、それぞれ略一定に維持するように、調節弁７４９ａ，７４９ｂの開度をそれぞれ制御する制御方法の一例について説明する。なお、調節弁７４９ａ，７４９ｂの制御方法は以下の方法に限定されるものではない。 That is, the control unit 750 controls the opening degrees of the control valves 749a and 749b, respectively, so that the temperatures measured by the thermometers 747a and 747b are maintained substantially constant. Further, the opening degrees of the control valves 749a and 749b are independently controlled by the control unit 750. Hereinafter, an example of a control method for controlling the opening degree of the control valves 749a and 749b so as to maintain the temperature measured by the thermometers 747a and 747b substantially constant will be described. The control method of the control valves 749a and 749b is not limited to the following method.
　まず、温度計７４７ａによる計測値が所定温度より高い場合、制御部７５０は、熱交換器７４２ａを通過する再生ドロー溶液の温度を低下させる制御を行う。この場合、制御部７５０は、調節弁７４９ｂの開度を小さくすることによって、バイパス配管を流れる希釈ドロー溶液の流量を低減させる。これに伴って、熱交換器７４２ｃを流れる希釈ドロー溶液の流量が増加して、熱交換器７４２ｃにおいて再生ドロー溶液から希釈ドロー溶液に移動する熱量が増加する。これにより、熱交換器７４２ａを通過する再生ドロー溶液の温度は、調節弁７４９ｂの開度を小さくする前に比して低下して、含水溶液の温度の上昇も抑制される。 First, when the value measured by the thermometer 747a is higher than the predetermined temperature, the control unit 750 controls to lower the temperature of the regenerated draw solution passing through the heat exchanger 742a. In this case, the control unit 750 reduces the flow rate of the diluted draw solution flowing through the bypass pipe by reducing the opening degree of the control valve 749b. Along with this, the flow rate of the diluted draw solution flowing through the heat exchanger 742c increases, and the amount of heat transferred from the regenerated draw solution to the diluted draw solution in the heat exchanger 742c increases. As a result, the temperature of the regenerated draw solution passing through the heat exchanger 742a is lowered as compared with that before the opening degree of the control valve 749b is reduced, and the temperature rise of the aqueous solution-containing solution is also suppressed.
　反対に、温度計７４７ａによる計測値が所定温度より低い場合、制御部７５０は、熱交換器７４２ａを通過する再生ドロー溶液の温度を上昇させる制御を行う。すなわち、制御部７５０は、調節弁７４９ｂの開度を大きくすることによって、バイパス配管を流れる希釈ドロー溶液の流量を増加させる。これに伴って、熱交換器７４２ｃを流れる希釈ドロー溶液の流量が低減して、熱交換器７４２ｃにおいて再生ドロー溶液から希釈ドロー溶液に移動する熱量が低減する。これにより、熱交換器７４２ａを通過する再生ドロー溶液の温度は、調節弁７４９ｂの開度を小さくする前に比して上昇して、含水溶液の温度も上昇される。 On the contrary, when the value measured by the thermometer 747a is lower than the predetermined temperature, the control unit 750 controls to raise the temperature of the regenerated draw solution passing through the heat exchanger 742a. That is, the control unit 750 increases the flow rate of the diluted draw solution flowing through the bypass pipe by increasing the opening degree of the control valve 749b. Along with this, the flow rate of the diluted draw solution flowing through the heat exchanger 742c is reduced, and the amount of heat transferred from the regenerated draw solution to the diluted draw solution in the heat exchanger 742c is reduced. As a result, the temperature of the regenerated draw solution passing through the heat exchanger 742a rises as compared with that before the opening degree of the control valve 749b is reduced, and the temperature of the aqueous solution containing water also rises.
　また、具体的に、調節弁７４９ｂが全閉の場合や比較的絞られている場合、熱交換器７４２ａには、調節弁７４９ｂが全開の場合に比して低い温度の再生ドロー溶液が供給される。この際、再生ドロー溶液の温度を低下させるために熱交換器７４２ａに供給される含水溶液は比較的少なくて良いため、前処理ユニット７４３や膜モジュール７４１に供給される含水溶液を一定にするための調節弁７４９ａからの廃棄量は低減される。 Specifically, when the control valve 749b is fully closed or relatively throttled, the heat exchanger 742a is supplied with a regenerated draw solution having a lower temperature than when the control valve 749b is fully open. To. At this time, since the amount of the aqueous solution supplied to the heat exchanger 742a in order to lower the temperature of the regenerated draw solution may be relatively small, in order to keep the aqueous solution supplied to the pretreatment unit 743 and the membrane module 741 constant. The amount of waste from the control valve 749a is reduced.
　一方、調節弁７４９ｂが全開の場合や比較的開けられている場合、熱交換器７４２ａに供給される再生ドロー溶液の温度は、調節弁７４９ｂが全閉の場合に比して高くなる。この際、再生ドロー溶液を冷却するとともに、温度計７４７ａにより計測される含水溶液の温度を所定温度に維持するために、熱交換器７４２ａに供給される含水溶液を多くする必要があるため、調節弁７４９ａからの廃棄量は増加する。 On the other hand, when the control valve 749b is fully open or relatively open, the temperature of the regenerated draw solution supplied to the heat exchanger 742a is higher than when the control valve 749b is fully closed. At this time, in order to cool the regenerated draw solution and maintain the temperature of the aqueous solution contained by the thermometer 747a at a predetermined temperature, it is necessary to increase the amount of the aqueous solution supplied to the heat exchanger 742a. The amount of waste from valve 749a increases.
　以上の制御原理に基づいて、温度計７４７ｂにより計測される温度を所定温度の例えば４０℃に維持するように、調節弁７４９ｂの開度を調節するとともに、温度計７４７ａの温度を所定温度の例えば４０℃に維持するように、調節弁７４９ｂの開度を調節する。ここで、調節弁７４９ｂの開度の調整のみで温度計７４７ａ，７４７ｂの計測値をいずれも一定に維持することが困難な場合には、さらに調節弁７４９ａの開度を調整することによって、温度計７４７ａ，７４７ｂの計測値をともに一定になるように調整する。 Based on the above control principle, the opening degree of the control valve 747b is adjusted so that the temperature measured by the thermometer 747b is maintained at a predetermined temperature, for example, 40 ° C., and the temperature of the thermometer 747a is adjusted, for example, at a predetermined temperature. The opening degree of the control valve 749b is adjusted so as to maintain the temperature at 40 ° C. Here, when it is difficult to keep the measured values of the thermometers 747a and 747b constant only by adjusting the opening degree of the control valve 749b, the temperature is further adjusted by adjusting the opening degree of the control valve 749a. Adjust the measured values of 747a and 747b so that they are both constant.
　以上のようにして、制御部７５０は、温度計７４７ａ，７４７ｂの計測値に基づいて調節弁７４９ａ，７４９ｂの開度を制御することによって、含水溶液の温度と再生ドロー溶液の温度とが互いに略同じ温度で所定温度になるように制御する。熱交換器７４２ａにおいて熱交換が行われて降温された再生ドロー溶液は膜モジュール７４１の他方の室に供給されるとともに、熱交換が行われて昇温された含水溶液は、前処理ユニット７４３に供給されて、濁質が除去される。前処理ユニット７４３から流出した含水溶液は、流量計７４８を通過して膜モジュール７４１における一方の室に供給される。膜モジュール７４１に供給される前の含水溶液が昇温されていることにより、膜モジュール７４１の透過水量（ｍ／日）を向上させることができる。また、膜モジュール７４１に供給される含水溶液の温度を一定に維持することによって、膜モジュール７４１における透過水量を安定化させることができる。 As described above, the control unit 750 controls the opening degree of the control valves 749a and 749b based on the measured values of the thermometers 747a and 747b, so that the temperature of the aqueous solution and the temperature of the regenerated draw solution are substantially equal to each other. It is controlled to reach a predetermined temperature at the same temperature. The regenerated draw solution that has been heated by heat exchange in the heat exchanger 742a is supplied to the other chamber of the membrane module 741, and the aqueous solution that has been heated by heat exchange is supplied to the pretreatment unit 743. It is fed and the turbidity is removed. The aqueous solution flowing out of the pretreatment unit 743 passes through the flow meter 748 and is supplied to one chamber of the membrane module 741. Since the temperature of the aqueous solution containing water before being supplied to the membrane module 741 is raised, the amount of permeated water (m / day) of the membrane module 741 can be improved. Further, by keeping the temperature of the aqueous solution supplied to the membrane module 741 constant, the amount of permeated water in the membrane module 741 can be stabilized.
　（正浸透流量調節工程）
　第４装置例においては、さらに、流量計７４８、調節弁７４９ａ、および制御部７５０によって、膜モジュール７４１に流入する含水溶液の流量を調節する正浸透流量調節工程が行われる。 (Forward osmosis flow rate adjustment process)
In the fourth device example, a forward osmosis flow rate adjusting step of adjusting the flow rate of the aqueous solution containing water flowing into the membrane module 741 is further performed by the flow meter 748, the control valve 749a, and the control unit 750.
　すなわち、外部から正浸透装置７４に供給される含水溶液は、熱交換器７４２ａを介し、前処理ユニット７４３によって濁質が除去された後、膜モジュール７４１に供給される。流量計７４８は、含水溶液の流れ方向に沿って膜モジュール７４１の上流側の流量を計測して、計測値を制御部７５０に供給する。 That is, the aqueous solution supplied from the outside to the forward osmosis device 74 is supplied to the membrane module 741 after the turbidity is removed by the pretreatment unit 743 via the heat exchanger 742a. The flow meter 748 measures the flow rate on the upstream side of the membrane module 741 along the flow direction of the aqueous solution, and supplies the measured value to the control unit 750.
　制御部７５０は、流量計７４８から供給された計測値と、あらかじめ設定された膜モジュール７４１に供給する際の所定流量とを比較する。計測値が所定流量より大きい場合、制御部７５０は、膜モジュール７４１に流入する含水溶液の流量を低減する制御を行う。 The control unit 750 compares the measured value supplied from the flow meter 748 with the predetermined flow rate when supplying to the preset membrane module 741. When the measured value is larger than the predetermined flow rate, the control unit 750 controls to reduce the flow rate of the aqueous solution containing water flowing into the membrane module 741.
　すなわち、制御部７５０は、調節弁７４９ａの開度を大きくすることによって、前処理ユニット７４３の上流側において、外部に廃棄する含水溶液の流量を増加させる。これにより、前処理ユニット７４３に供給される含水溶液の流量が減少して、膜モジュール７４１に供給される含水溶液の流量が低減される。反対に、計測値が所定流量より小さい場合、制御部７５０は、膜モジュール７４１に流入する含水溶液の流量を増加させる制御を行う。すなわち、制御部７５０は、調節弁７４９ａの開度を小さくすることによって、前処理ユニット７４３の上流側において、外部に廃棄する含水溶液の流量を減少させる。これにより、前処理ユニット７４３に供給される含水溶液の流量が増加して、膜モジュール７４１に供給される含水溶液の流量が増加される。したがって、膜モジュール７４１に流入する含水溶液の流量を略一定の所定流量に維持することができる。 That is, the control unit 750 increases the flow rate of the aqueous solution containing water to be discarded to the outside on the upstream side of the pretreatment unit 743 by increasing the opening degree of the control valve 749a. As a result, the flow rate of the aqueous solution supplied to the pretreatment unit 743 is reduced, and the flow rate of the aqueous solution supplied to the membrane module 741 is reduced. On the contrary, when the measured value is smaller than the predetermined flow rate, the control unit 750 controls to increase the flow rate of the aqueous solution containing the aqueous solution flowing into the membrane module 741. That is, the control unit 750 reduces the flow rate of the aqueous solution containing water to be discarded to the outside on the upstream side of the pretreatment unit 743 by reducing the opening degree of the control valve 749a. As a result, the flow rate of the aqueous solution supplied to the pretreatment unit 743 is increased, and the flow rate of the aqueous solution supplied to the membrane module 741 is increased. Therefore, the flow rate of the aqueous solution containing water flowing into the membrane module 741 can be maintained at a substantially constant predetermined flow rate.
　（第４装置実施例）
　次に、以上のように構成された正浸透装置７４の第４装置実施例について説明する。なお、第４実施例においては、正浸透装置７４を用いて、１００Ｌ／ｈの流量のブローダウン水から６７Ｌ／ｈの透過水を生成する場合を例に説明する。 (Example of the fourth apparatus)
Next, a fourth device embodiment of the forward osmosis device 74 configured as described above will be described. In the fourth embodiment, a case where the forward osmosis device 74 is used to generate 67 L / h of permeated water from blow-down water having a flow rate of 100 L / h will be described as an example.
　第４実施例においては、正浸透装置７４に外部から導入されたブローダウン水に対して熱交換器７４２ａによって熱交換が行われる。ブローダウン水は、熱交換器７４２ａによって、４０℃の温度に昇温されて前処理ユニット７４３および膜モジュール７４１に供給される。 In the fourth embodiment, heat exchange is performed by the heat exchanger 742a with respect to the blowdown water introduced from the outside into the forward osmosis device 74. The blowdown water is heated to a temperature of 40 ° C. by the heat exchanger 742a and supplied to the pretreatment unit 743 and the membrane module 741.
　ここで、含水溶液の流れ方向に沿った前処理ユニット７４３の上流側、かつ熱交換器７４２ａの下流側の温度に応じて、調節弁７４９ｂの開度が制御され、熱交換器７４２ｃに通過する希釈ドロー溶液の流量が制御される。これにより、熱交換器７４２ｃにおいて再生ドロー溶液から希釈ドロー溶液に移動する熱量が制御されて、熱交換器７４２ａを通過する再生ドロー溶液の温度が制御され、再生ドロー溶液からブローダウン水に移動する熱量が制御される。膜モジュール７４１によって濃縮されたブローダウン水は、３３Ｌ／ｈの流量で膜モジュール７４１から排出される。すなわち、膜モジュール７４１において、６７Ｌ／ｈの流量で水の移動が行われる。 Here, the opening degree of the control valve 749b is controlled according to the temperature on the upstream side of the pretreatment unit 743 and the downstream side of the heat exchanger 742a along the flow direction of the aqueous solution, and passes through the heat exchanger 742c. The flow rate of the diluted draw solution is controlled. As a result, the amount of heat transferred from the regenerated draw solution to the diluted draw solution is controlled in the heat exchanger 742c, the temperature of the regenerated draw solution passing through the heat exchanger 742a is controlled, and the regenerated draw solution is transferred to the blowdown water. The amount of heat is controlled. The blowdown water concentrated by the membrane module 741 is discharged from the membrane module 741 at a flow rate of 33 L / h. That is, in the membrane module 741, water is moved at a flow rate of 67 L / h.
　一方、再生ドロー溶液は、熱交換器７４２ａにおけるブローダウン水との熱交換によって温度調整が行われ、４０℃の温度に降温される。再生ドロー溶液は、膜モジュール７４１に供給されて希釈され、希釈ドロー溶液として流出する。ここで、再生ドロー溶液の流量は１００Ｌ／ｈである。膜モジュール７４１から流出される希釈ドロー溶液は、温度が４０℃であり、流量が１６７Ｌ／ｈである。その後、希釈ドロー溶液は、熱交換器７４２ｂにおいて温度が８８℃の水リッチ溶液と熱交換されて加熱され、４０℃から５２℃の温度まで昇温される。 On the other hand, the temperature of the regenerated draw solution is adjusted by heat exchange with the blowdown water in the heat exchanger 742a, and the temperature is lowered to 40 ° C. The regenerated draw solution is supplied to the membrane module 741 to be diluted and discharged as a diluted draw solution. Here, the flow rate of the regenerated draw solution is 100 L / h. The diluted draw solution flowing out of the membrane module 741 has a temperature of 40 ° C. and a flow rate of 167 L / h. Then, the diluted draw solution is heated by heat exchange with the water-rich solution having a temperature of 88 ° C. in the heat exchanger 742b, and the temperature is raised from 40 ° C. to 52 ° C.
　続いて、希釈ドロー溶液は、熱交換器７４２ｃに供給されて熱交換が行われる。熱交換器７４２ｃにおいて希釈ドロー溶液は、含水溶液の流れ方向に沿った膜モジュール７４１の上流側の温度に応じて制御される調節弁７４９ｂの開度に対応して温度が制御され、５２℃から５２℃以上７１℃以下の温度に昇温される。その後、加熱器７４４に供給されてさらに加熱され、８８℃の温度まで昇温される。 Subsequently, the diluted draw solution is supplied to the heat exchanger 742c for heat exchange. In the heat exchanger 742c, the temperature of the diluted draw solution is controlled from 52 ° C. according to the opening degree of the control valve 749b, which is controlled according to the temperature on the upstream side of the membrane module 741 along the flow direction of the aqueous solution. The temperature is raised to 52 ° C. or higher and 71 ° C. or lower. After that, it is supplied to the heater 744 and further heated to raise the temperature to 88 ° C.
　希釈ドロー溶液は、分離槽７４５に供給されて、再生ドロー溶液と水リッチ溶液とに相分離される。分離槽７４５から流出される再生ドロー溶液は、温度が８８℃、流量が１０００Ｌ／ｈである。再生ドロー溶液は、熱交換器７４２ｃに供給されて低温の希釈ドロー溶液と熱交換される。熱交換器７４２ｃにおける熱交換は、調節弁７４９ｂの開度に応じて温度が制御され、８８℃から６５℃以上８８℃未満の温度に降温される。 The diluted draw solution is supplied to the separation tank 745 and phase-separated into the regenerated draw solution and the water-rich solution. The regenerated draw solution flowing out of the separation tank 745 has a temperature of 88 ° C. and a flow rate of 1000 L / h. The regenerated draw solution is supplied to the heat exchanger 742c to exchange heat with the low temperature diluted draw solution. The temperature of the heat exchange in the heat exchanger 742c is controlled according to the opening degree of the control valve 749b, and the temperature is lowered from 88 ° C. to a temperature of 65 ° C. or higher and lower than 88 ° C.
　分離槽７４５から流出される水リッチ溶液は、温度が８８℃、流量が６７Ｌ／ｈである。水リッチ溶液は、熱交換器７４２ｂに供給されて４０℃の希釈ドロー溶液と熱交換されて、８８℃から４５℃まで降温された後に、最終処理ユニット７４６に供給される。最終処理ユニット７４６においては、６７Ｌ／ｈの流量で透過水が得られる。なお、最終処理ユニット７４６において、透過水から分離されるドロー溶液については、少量であることから考慮していない。以上により、１００Ｌ／ｈの流量のブローダウン水から、６７Ｌ／ｈの流量の透過水が得られる。 The water-rich solution flowing out of the separation tank 745 has a temperature of 88 ° C. and a flow rate of 67 L / h. The water-rich solution is supplied to the heat exchanger 742b for heat exchange with the diluted draw solution at 40 ° C., cooled from 88 ° C. to 45 ° C., and then supplied to the final treatment unit 746. In the final treatment unit 746, permeated water is obtained at a flow rate of 67 L / h. In the final treatment unit 746, the draw solution separated from the permeated water is not considered because it is a small amount. As described above, permeated water having a flow rate of 67 L / h can be obtained from the blow-down water having a flow rate of 100 L / h.
　以上説明したように第４装置例によれば、熱交換器７４２ｃにおける希釈ドロー溶液の流れ方向に沿った上流側と下流側とをバイパスするバイパス配管の流量を調整する調節弁７４９ｂを設け、膜モジュール７４１に流入する含水溶液の温度に応じて、調節弁７４９ｂの開度を制御することによって、含水溶液と再生ドロー溶液との熱交換を制御していることにより、膜モジュール７４１に供給する含水溶液および再生ドロー溶液を所望の温度に調整している。これにより、膜モジュール７４１において含水溶液およびドロー溶液の温度を極めて近い温度にできるので、膜モジュール７４１における処理効率を安定化できる。 As described above, according to the fourth apparatus example, a control valve 749b for adjusting the flow rate of the bypass pipe that bypasses the upstream side and the downstream side along the flow direction of the diluted draw solution in the heat exchanger 742c is provided, and a membrane is provided. By controlling the opening degree of the control valve 749b according to the temperature of the aqueous solution flowing into the module 741, the heat exchange between the aqueous solution and the regenerated draw solution is controlled, so that the membrane module 741 is supplied. The aqueous solution and the regenerated draw solution are adjusted to the desired temperature. As a result, the temperatures of the aqueous solution and the draw solution in the membrane module 741 can be made extremely close to each other, so that the processing efficiency in the membrane module 741 can be stabilized.
　第４装置例によれば、含水溶液の流れ方向に沿った少なくとも膜モジュール７４１の上流側に調節弁７４９ａを設け、膜モジュール７４１の上流側の流量に応じて調節弁７４９ａの開度を調節していることにより、膜モジュール７４１に供給される含水溶液を所定流量に維持することができる。これにより、膜モジュール７４１における処理効率をより一層安定化することができる。 According to the fourth device example, the control valve 749a is provided at least on the upstream side of the membrane module 741 along the flow direction of the aqueous solution, and the opening degree of the control valve 749a is adjusted according to the flow rate on the upstream side of the membrane module 741. Therefore, the aqueous solution supplied to the membrane module 741 can be maintained at a predetermined flow rate. Thereby, the processing efficiency in the membrane module 741 can be further stabilized.
　なお、正浸透装置７４において、熱交換器７４２ｂを設けない構成も可能である。すなわち、正浸透装置７４において、希釈ドロー溶液と水リッチ溶液との間で熱交換を行わない構成も可能である。また、正浸透装置７４において、正浸透装置７４において、前処理ユニット７４３を設けない構成や、前処理ユニット７４３および熱交換器７４２ｂをいずれも設けない構成も可能である。この場合、正浸透装置７４に導入される前段階において、含水溶液に対して濁質などを除去する前処理が実行される。 It should be noted that the forward penetration device 74 may be configured without the heat exchanger 742b. That is, in the forward osmosis apparatus 74, a configuration in which heat exchange is not performed between the diluted draw solution and the water-rich solution is also possible. Further, in the forward osmosis device 74, the forward osmosis device 74 may be configured not to be provided with the pretreatment unit 743 or to be provided with neither the pretreatment unit 743 nor the heat exchanger 742b. In this case, a pretreatment for removing turbidity or the like from the aqueous solution is executed in the pre-stage of being introduced into the forward osmosis apparatus 74.
　以上、本発明の実施形態について具体的に説明したが、本発明は、上述の実施形態に限定されるものではなく、本発明の技術的思想に基づく各種の変形が可能である。例えば、上述の実施形態において挙げた数値はあくまでも例に過ぎず、必要に応じてこれと異なる数値を用いても良く、本実施形態による本発明の開示の一部をなす記述および図面により本発明は限定されることはない。 Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications based on the technical idea of the present invention are possible. For example, the numerical values given in the above-described embodiment are merely examples, and different numerical values may be used if necessary, and the present invention is based on the description and drawings which form a part of the disclosure of the present invention according to the present embodiment. Is not limited.
　例えば、上述した実施形態においては、シリカの凝集剤として、ＰＡＣを用いているが、ＰＡＣ以外の凝集剤を用いることも可能であり、反応槽に沈殿したスラッジＳを凝集剤として使用することが可能である。具体的に、ＰＡＣ以外にも、例えば水酸化アルミニウム（Ａｌ（ＯＨ）3）、硫酸アルミニウム（Ａｌ2（ＳＯ4）3）などのアルミニウム塩、例えばＭｇ（ＯＨ）2、塩化マグネシウム（ＭｇＣｌ2）などのマグネシウム塩、例えば塩化第二鉄（ＦｅＣｌ3）、硫酸第二鉄（Ｆｅ2（ＳＯ4）3）、ポリシリカ鉄（ＰＳＩ）などの鉄塩、ならびに例えばポリアクリルアミド系などポリマー系凝集剤から選ばれた少なくとも１種類の凝集剤、または上述した凝集剤を２つ以上組み合わせた凝集剤においても、上述と同様の反応機構を経ることによって、ＰＡＣの場合と同様の効果を得ることが可能である。 For example, in the above-described embodiment, PAC is used as the silica flocculant, but a flocculant other than PAC can also be used, and sludge S precipitated in the reaction vessel can be used as the flocculant. It is possible. Specifically, in addition to PAC, aluminum salts such as aluminum hydroxide (Al (OH) 3 ) and aluminum sulfate (Al 2 (SO 4 ) 3 ), such as Mg (OH) 2 and magnesium chloride (MgCl 2 ). From magnesium salts such as ferric chloride (FeCl 3 ), ferrous sulfate (Fe 2 (SO 4 ) 3 ), iron salts such as polysilica iron (PSI), and polymer flocculants such as polyacrylamides. Even in the case of at least one selected coagulant or a coagulant in which two or more of the above-mentioned coagulants are combined, the same effect as in the case of PAC can be obtained by going through the same reaction mechanism as described above. be.
　上述した第１～第４の実施形態および第１～第４変形例による水処理装置１～８は適宜組み合わせることができる。例えば、第１の実施形態による第１凝集沈殿部１０の後段の軟水器３０と、第４の実施形態による第２凝集沈殿部５０の後段の軟水器３０とをともに設けることも可能である。 The water treatment devices 1 to 8 according to the first to fourth embodiments and the first to fourth modifications described above can be appropriately combined. For example, it is also possible to provide both the water softener 30 in the subsequent stage of the first coagulation and sedimentation portion 10 according to the first embodiment and the water softener 30 in the subsequent stage of the second coagulation and sedimentation portion 50 according to the fourth embodiment.
　本発明は、ゼロ排水プロセスに適用して好適なものである。 The present invention is suitable for application to a zero drainage process.
１，２，３，４，５，６，７，８　水処理装置
１０　第１凝集沈殿部
１０Ａ，１０Ｂ，１０Ｃ，１０Ｄ，５０Ａ，５０Ｂ，５０Ｃ，５０Ｄ　凝集沈殿部
１１　受入槽
１２　反応槽
１３　ｐＨ調整槽
１４　ポンプ
１５　脱水機
１６，１７，５１，５２　シリカ濃度計
１８　汚泥貯留槽
１９　薬注装置
２０　第１ろ過部
３０　軟水器
４０　低圧逆浸透部
５０　第２凝集沈殿部
６０　第２ろ過部
７０，７１，７２，７３，７４　正浸透装置
８０　蒸留晶析部
９０　高圧逆浸透部
１２１　第１反応槽
１２１ａ，１２２ａ　攪拌部
１２２　第２反応槽
１２３　沈殿槽
７１１，７２１，７３１，７４１　膜モジュール
７１１ａ，７２１ａ，７３１ａ，７４１ａ　半透膜
７１２，７１３，７２２，７２３，７２４，７３２，７３３，７３４，７４２ａ，７４２ｂ，７４２ｃ　熱交換器
７１４，７２５，７３５，７４４　加熱器
７１５，７２６，７３６，７４５　分離槽
７１６，７２７，７３７，７４６　最終処理ユニット
７４３　前処理ユニット
７４７ａ，７４７ｂ　温度計
７４８　流量計
７４９ａ，７４９ｂ　調節弁
７５０　制御部
Ｓ　スラッジ 1,2,3,4,5,6,7,8 Water treatment equipment 10 First coagulation sedimentation section 10A, 10B, 10C, 10D, 50A, 50B, 50C, 50D Coagulation sedimentation section 11 Receiving tank 12 Reaction tank 13 pH Adjustment tank 14 Pump 15 Dehydrator 16, 17, 51, 52 Silica concentration meter 18 Sewage storage tank 19 Chemical injection device 20 First filtration unit 30 Water softener 40 Low pressure reverse osmosis unit 50 Second coagulation sedimentation unit 60 Second filtration unit 70 , 71, 72, 73, 74 Forward osmosis device 80 Distillation crystallization section 90 High-pressure reverse osmosis section 121 First reaction tank 121a, 122a Stirring section 122 Second reaction tank 123 Sedimentation tank 711,721,731,741 Film module 711a, 721a, 731a, 741a Semipermeable membrane 712,713,722,723,724,732,733,734,742a, 742b, 742c Heat exchanger 714,725,735,744 Heater 715,726,736,745 Separation tank 716, 727, 737, 746 Final processing unit 743 Pretreatment unit 747a, 747b Thermometer 748 Flow meter 749a, 749b Control valve 750 Control unit S sludge

Claims (19)

  1. 　シリカを含有した不純物を含む被処理水から水を抽出する水処理装置であって、
    　前記被処理水から前記不純物の少なくとも一部を凝集させて除去する複数の凝集沈殿部と、
    　溶媒として水を含む含水溶液から水を抽出可能な正浸透膜および逆浸透膜の少なくとも一方を有して前記被処理水から透過水を抽出するとともに、前記被処理水から前記透過水が抽出されて得られた濃縮水を排出する複数の水抽出部と、を備え、
    　前記被処理水の流れ方向に沿って、前記複数の凝集沈殿部のうちの一部である第１凝集沈殿部の後段に前記複数の水抽出部のうちの一部である第１水抽出部と、前記第１水抽出部の後段に前記複数の凝集沈殿部のうちの他部である第２凝集沈殿部と、前記第２凝集沈殿部の後段に前記複数の水抽出部のうちの他部である第２水抽出部とが設けられ、
    　前記第１凝集沈殿部は、前記被処理水から前記シリカの一部を除去した後、前記被処理水を前記第１水抽出部に供給し、
    　前記第１水抽出部は、前記シリカの一部が除去された前記被処理水から前記透過水を抽出するとともに前記濃縮水を排出して、前記濃縮水を前記第２凝集沈殿部に供給し、
    　前記第２凝集沈殿部は、前記濃縮水から前記シリカの残部を除去した後、前記濃縮水を前記第２水抽出部に供給し、
    　前記第２水抽出部は、前記正浸透膜および前記逆浸透膜の少なくとも一方を有し、前記第２凝集沈殿部から供給された前記濃縮水から透過水を抽出するとともに、前記濃縮水をさらに濃縮した高濃縮水を排出する
    　ことを特徴とする水処理装置。     A water treatment device that extracts water from water to be treated containing impurities containing silica.
    A plurality of coagulated sedimentation portions that agglomerate and remove at least a part of the impurities from the water to be treated.
    The permeated water is extracted from the water to be treated by having at least one of a normal osmosis membrane and a reverse osmosis membrane capable of extracting water from an aqueous solution containing water as a solvent, and the permeated water is extracted from the water to be treated. It is equipped with a plurality of water extraction units that discharge the concentrated water obtained.
    Along the flow direction of the water to be treated, a first water extraction unit which is a part of the plurality of water extraction parts is placed after the first coagulation sedimentation part which is a part of the plurality of coagulation sedimentation parts. The second coagulation sedimentation section, which is the other part of the plurality of coagulation sedimentation sections, is located after the first water extraction section, and the other of the plurality of water extraction sections is behind the second coagulation sedimentation section. A second water extraction unit, which is a unit, is provided.
    The first coagulation sedimentation section removes a part of the silica from the water to be treated, and then supplies the water to be treated to the first water extraction section.
    The first water extraction unit extracts the permeated water from the water to be treated from which a part of the silica has been removed, discharges the concentrated water, and supplies the concentrated water to the second coagulation sedimentation unit. ,
    The second coagulation sedimentation section removes the remainder of the silica from the concentrated water, and then supplies the concentrated water to the second water extraction section.
    The second water extraction unit has at least one of the forward osmosis membrane and the reverse osmosis membrane, extracts permeated water from the concentrated water supplied from the second coagulation sedimentation unit, and further extracts the concentrated water. A water treatment device characterized by discharging highly concentrated water.
  2. 　前記被処理水または前記濃縮水のろ過を行うろ過部が複数設けられ、
    　前記被処理水の流れ方向に沿って、
    　前記第１凝集沈殿部の後段かつ前記第１水抽出部の前段に、前記複数のろ過部の一部である第１ろ過部が設けられ、
    　前記第２凝集沈殿部の後段かつ前記第２水抽出部の前段に、前記複数のろ過部の他部である第２ろ過部が設けられている
    　ことを特徴とする請求項１記載の水処理装置。     A plurality of filtration units for filtering the water to be treated or the concentrated water are provided.
    Along the flow direction of the water to be treated,
    A first filtration unit, which is a part of the plurality of filtration units, is provided after the first coagulation sedimentation unit and before the first water extraction unit.
    The water treatment according to claim 1, wherein a second filtration part, which is another part of the plurality of filtration parts, is provided after the second coagulation sedimentation part and before the second water extraction part. Device.
  3. 　前記第１ろ過部に供給される前記被処理水、および前記第２ろ過部に供給される前記濃縮水のｐＨを、４以上８以下に調整可能に構成されている
    　ことを特徴とする請求項２に記載の水処理装置。     The claim is characterized in that the pH of the water to be treated supplied to the first filtration unit and the concentrated water supplied to the second filtration unit can be adjusted to 4 or more and 8 or less. 2. The water treatment apparatus according to 2.
  4. 　前記第１水抽出部が、低圧逆浸透膜を有する低圧逆浸透部からなるとともに、前記第２水抽出部が、高圧逆浸透膜を有する高圧逆浸透部または前記正浸透膜を有する正浸透部からなる
    　ことを特徴とする請求項１～３のいずれか１項に記載の水処理装置。     The first water extraction unit is composed of a low-pressure reverse osmosis portion having a low-pressure reverse osmosis membrane, and the second water extraction unit is a high-pressure reverse osmosis portion having a high-pressure reverse osmosis membrane or a forward osmosis portion having the forward osmosis membrane. The water treatment apparatus according to any one of claims 1 to 3, wherein the water treatment apparatus comprises.
  5. 　前記第２水抽出部の後段に、前記高濃縮水に対して蒸留処理および晶析処理の少なくとも一方の処理を行って精製水を排出する蒸留晶析部が設けられている
    　ことを特徴とする請求項１～４のいずれか１項に記載の水処理装置。     A distillation crystallization section is provided after the second water extraction section, in which the highly concentrated water is subjected to at least one of a distillation treatment and a crystallization treatment to discharge purified water. The water treatment apparatus according to any one of claims 1 to 4.
  6. 　前記不純物がカルシウムを含み、
    　前記被処理水の流れ方向に沿って、
    　前記第１凝集沈殿部の後段かつ前記第１水抽出部の前段と、前記第２凝集沈殿部の後段かつ前記第２水抽出部の前段との少なくとも一方に、前記カルシウムを除去可能なカルシウム除去部が設けられている
    　ことを特徴とする請求項１～５のいずれか１項に記載の水処理装置。     The impurities contain calcium
    Along the flow direction of the water to be treated,
    Calcium removal capable of removing calcium in at least one of the latter stage of the first coagulation sedimentation portion and the front stage of the first water extraction portion and the latter stage of the second coagulation sedimentation portion and the front stage of the second water extraction portion. The water treatment apparatus according to any one of claims 1 to 5, wherein the unit is provided.
  7. 　前記不純物がカルシウムを含み、
    　前記被処理水の流れ方向に沿った前記第１水抽出部の前段における前記被処理水にカルシウム分散剤を添加可能に構成されている
    　ことを特徴とする請求項１～６のいずれか１項に記載の水処理装置。     The impurities contain calcium
    Any one of claims 1 to 6, wherein a calcium dispersant can be added to the water to be treated in the previous stage of the first water extraction unit along the flow direction of the water to be treated. The water treatment apparatus according to.
  8. 　前記凝集沈殿部において前記シリカを凝集させる凝集剤が、ポリ塩化アルミニウムまたは塩化アルミニウムと、前記被処理水にポリ塩化アルミニウムまたは塩化アルミニウムが添加されて前記凝集沈殿部に沈殿された凝集沈殿汚泥と、を含む
    　ことを特徴とする請求項１～７のいずれか１項に記載の水処理装置。     The coagulant that coagulates the silica in the coagulation sedimentation portion is polyaluminum chloride or aluminum chloride, and coagulation sedimentation sludge in which polyaluminum chloride or aluminum chloride is added to the water to be treated and precipitated in the coagulation sedimentation portion. The water treatment apparatus according to any one of claims 1 to 7, wherein the water treatment apparatus comprises.
  9. 　前記不純物がマグネシウムを含む
    　ことを特徴とする請求項１～８のいずれか１項に記載の水処理装置。     The water treatment apparatus according to any one of claims 1 to 8, wherein the impurity contains magnesium.
  10. 　シリカを含有した不純物を含む被処理水から水を抽出する水処理方法であって、
    　前記被処理水に対して、前記不純物に含まれる前記シリカの一部を凝集させて除去する第１凝集沈殿工程と、
    　前記第１凝集沈殿工程の後に、正浸透膜および逆浸透膜の少なくとも一方によって前記被処理水から透過水を抽出するとともに、前記被処理水から前記透過水を抽出して得られた濃縮水を排出する第１水抽出工程と、
    　前記第１水抽出工程の後に、前記濃縮水に対して前記不純物に含まれる前記シリカの残部を凝集させて除去する第２凝集沈殿工程と、
    　前記第２凝集沈殿工程の後に、正浸透膜および逆浸透膜の少なくとも一方によって前記濃縮水から透過水を抽出するとともに、前記濃縮水をさらに濃縮した高濃縮水を排出する第２水抽出工程と、を含む
    　ことを特徴とする水処理方法。     A water treatment method for extracting water from water to be treated containing impurities containing silica.
    A first coagulation-precipitation step of coagulating and removing a part of the silica contained in the impurities with respect to the water to be treated.
    After the first coagulation sedimentation step, the permeated water is extracted from the water to be treated by at least one of the forward osmosis membrane and the reverse osmosis membrane, and the concentrated water obtained by extracting the permeated water from the water to be treated is used. The first water extraction process to be discharged and
    After the first water extraction step, a second coagulation-sedimentation step of agglomerating and removing the remainder of the silica contained in the impurities with respect to the concentrated water.
    After the second coagulation sedimentation step, a second water extraction step of extracting permeated water from the concentrated water by at least one of a forward osmosis membrane and a reverse osmosis membrane and discharging highly concentrated water obtained by further concentrating the concentrated water. A water treatment method comprising ,.
  11. 　前記第１凝集沈殿工程および前記第２凝集沈殿工程において、前記被処理水のｐＨを、８以上１２以下に調整する
    　ことを特徴とする請求項１０に記載の水処理方法。     The water treatment method according to claim 10, wherein the pH of the water to be treated is adjusted to 8 or more and 12 or less in the first coagulation-sedimentation step and the second coagulation-sedimentation step.
  12. 　前記第１凝集沈殿工程の後かつ前記第１水抽出工程の前に、前記被処理水をろ過する第１ろ過工程と、
    　前記第２凝集沈殿工程の後かつ前記第２水抽出工程の前に、前記濃縮水をろ過する第２ろ過工程と、を含む
    　ことを特徴とする請求項１０または１１に記載の水処理方法。     After the first coagulation sedimentation step and before the first water extraction step, a first filtration step of filtering the water to be treated and a first filtration step.
    The water treatment method according to claim 10 or 11, further comprising a second filtration step of filtering the concentrated water after the second coagulation-sedimentation step and before the second water extraction step.
  13. 　前記第１ろ過工程における前記被処理水のｐＨを４以上８以下に調整し、
    　前記第２ろ過工程における前記濃縮水のｐＨを４以上８以下に調整する
    　ことを特徴とする請求項１２に記載の水処理方法。     The pH of the water to be treated in the first filtration step is adjusted to 4 or more and 8 or less.
    The water treatment method according to claim 12, wherein the pH of the concentrated water in the second filtration step is adjusted to 4 or more and 8 or less.
  14. 　前記第１水抽出工程が、低圧逆浸透膜によって前記透過水を抽出する低圧逆浸透工程を含むとともに、前記第２水抽出工程が、高圧逆浸透膜によって前記透過水を抽出する高圧逆浸透工程、または前記正浸透膜によって前記透過水を抽出する正浸透工程を含む
    　ことを特徴とする請求項１０～１３のいずれか１項に記載の水処理方法。     The first water extraction step includes a low-pressure reverse osmosis step of extracting the permeated water with a low-pressure reverse osmosis membrane, and the second water extraction step is a high-pressure reverse osmosis step of extracting the permeated water with a high-pressure reverse osmosis membrane. The water treatment method according to any one of claims 10 to 13, further comprising a reverse osmosis step of extracting the permeated water by the reverse osmosis membrane.
  15. 　前記第２水抽出工程の後に、前記高濃縮水に対して蒸留処理および晶析処理の少なくとも一方を行って精製水を排出する蒸留晶析工程を含む
    　ことを特徴とする請求項１０～１４のいずれか１項に記載の水処理方法。     Claims 10 to 14 include, after the second water extraction step, a distillation crystallization step of discharging purified water by performing at least one of a distillation treatment and a crystallization treatment on the highly concentrated water. The water treatment method according to any one item.
  16. 　前記不純物がカルシウムを含み、
    　前記第１凝集沈殿工程の後かつ前記第１水抽出工程の前と、前記第２凝集沈殿工程の後かつ前記第２水抽出工程の前との少なくとも一方において、前記カルシウムを除去するカルシウム除去工程を含む
    　ことを特徴とする請求項１０～１５のいずれか１項に記載の水処理方法。     The impurities contain calcium
    A calcium removal step of removing calcium at least after the first coagulation-precipitation step and before the first water extraction step, after the second coagulation-sedimentation step and before the second water extraction step. The water treatment method according to any one of claims 10 to 15, wherein the water treatment method comprises.
  17. 　前記不純物がカルシウムを含み、
    　前記第１水抽出工程の前に、前記被処理水にカルシウム分散剤を添加するカルシウム分散工程を含む
    　ことを特徴とする請求項１０～１６のいずれか１項に記載の水処理方法。     The impurities contain calcium
    The water treatment method according to any one of claims 10 to 16, further comprising a calcium dispersion step of adding a calcium dispersant to the water to be treated before the first water extraction step.
  18. 　前記第１凝集沈殿工程および前記第２凝集沈殿工程において前記シリカを凝集させる凝集剤が、ポリ塩化アルミニウムまたは塩化アルミニウムと、前記被処理水にポリ塩化アルミニウムまたは塩化アルミニウムが添加されて前記第１凝集沈殿工程および前記第２凝集沈殿工程の少なくとも一方において凝集沈殿された凝集沈殿汚泥と、を含む
    　ことを特徴とする請求項１０～１７のいずれか１項に記載の水処理方法。     The coagulant that agglomerates the silica in the first coagulation-precipitation step and the second coagulation-sedimentation step is polyaluminum chloride or aluminum chloride, and polyaluminum chloride or aluminum chloride is added to the water to be treated to form the first coagulation. The water treatment method according to any one of claims 10 to 17, wherein the coagulated sedimentation sludge that has been coagulated and precipitated in at least one of the precipitation step and the second coagulation sedimentation step is included.
  19. 　前記不純物がマグネシウムを含む
    　ことを特徴とする請求項１０～１８のいずれか１項に記載の水処理方法。     The water treatment method according to any one of claims 10 to 18, wherein the impurity contains magnesium.
PCT/JP2022/000583 2021-01-13 2022-01-11 Water treatment device and water treatment method WO2022153980A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2021003270 2021-01-13
JP2021-003270 2021-01-13
JP2021139894A JP7168739B2 (en) 2021-01-13 2021-08-30 Water treatment device and water treatment method
JP2021-139894 2021-08-30

Publications (1)

Publication Number Publication Date
WO2022153980A1 true WO2022153980A1 (en) 2022-07-21

Family

ID=82446277

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/000583 WO2022153980A1 (en) 2021-01-13 2022-01-11 Water treatment device and water treatment method

Country Status (1)

Country Link
WO (1) WO2022153980A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11795071B2 (en) 2019-08-22 2023-10-24 Saline Water Conversion Corporation Multi-valent ion concentration using multi-stage nanofiltration
US11806668B2 (en) 2021-12-14 2023-11-07 Saline Water Conversion Corporation Method and system for extraction of minerals based on divalent cations from brine
US11884567B2 (en) 2019-04-01 2024-01-30 Saline Water Conversion Corporation Desalination brine concentration system and method

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013153587A1 (en) * 2012-04-11 2013-10-17 Ｊｆｅエンジニアリング株式会社 Method and device for treating accompanying water from well
JP2014233699A (en) * 2013-06-04 2014-12-15 水ｉｎｇ株式会社 Method and apparatus for removing silica from treatment target water
WO2015002309A1 (en) * 2013-07-05 2015-01-08 三菱重工業株式会社 Water treatment system, water treatment method, cooling facility and power generating facility
WO2016147414A1 (en) * 2015-03-19 2016-09-22 三菱重工業株式会社 Water treatment system and power generation apparatus
JP2016193435A (en) * 2011-07-12 2016-11-17 高砂熱学工業株式会社 Flushing wastewater treatment method
JP2018079425A (en) * 2016-11-16 2018-05-24 オルガノ株式会社 Method and device for treating waste water
JP2019171309A (en) * 2018-03-29 2019-10-10 水ｉｎｇ株式会社 Coagulation sedimentation apparatus and coagulation sedimentation method
JP2020058963A (en) * 2018-10-05 2020-04-16 オルガノ株式会社 Water treatment device and water treatment method

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016193435A (en) * 2011-07-12 2016-11-17 高砂熱学工業株式会社 Flushing wastewater treatment method
WO2013153587A1 (en) * 2012-04-11 2013-10-17 Ｊｆｅエンジニアリング株式会社 Method and device for treating accompanying water from well
JP2014233699A (en) * 2013-06-04 2014-12-15 水ｉｎｇ株式会社 Method and apparatus for removing silica from treatment target water
WO2015002309A1 (en) * 2013-07-05 2015-01-08 三菱重工業株式会社 Water treatment system, water treatment method, cooling facility and power generating facility
WO2016147414A1 (en) * 2015-03-19 2016-09-22 三菱重工業株式会社 Water treatment system and power generation apparatus
JP2018079425A (en) * 2016-11-16 2018-05-24 オルガノ株式会社 Method and device for treating waste water
JP2019171309A (en) * 2018-03-29 2019-10-10 水ｉｎｇ株式会社 Coagulation sedimentation apparatus and coagulation sedimentation method
JP2020058963A (en) * 2018-10-05 2020-04-16 オルガノ株式会社 Water treatment device and water treatment method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11884567B2 (en) 2019-04-01 2024-01-30 Saline Water Conversion Corporation Desalination brine concentration system and method
US11795071B2 (en) 2019-08-22 2023-10-24 Saline Water Conversion Corporation Multi-valent ion concentration using multi-stage nanofiltration
US11806668B2 (en) 2021-12-14 2023-11-07 Saline Water Conversion Corporation Method and system for extraction of minerals based on divalent cations from brine

Similar Documents

Publication Publication Date Title
WO2022153980A1 (en) Water treatment device and water treatment method
JP6495207B2 (en) Recovery of retrograde solubility solutes for forward osmosis water treatment
CN108218078B (en) Method and system for treating salt-containing wastewater
CN104692574B (en) Treatment method of high saline wastewater
US9266762B2 (en) Membrane filtration process with high water recovery
CN105000737B (en) A kind of Industrial sewage treatment system and sewage water treatment method
WO2012120912A1 (en) System for producing fresh water
JPH10503414A (en) Reverse osmosis for water treatment enhanced by microfiltration
JPWO2013153587A1 (en) Method and apparatus for treatment of associated water from a well
WO2013134710A1 (en) Methods for osmotic concentration of hyper saline streams
CN105198141A (en) High-temperature high-salinity wastewater zero-discharging method
KR101344784B1 (en) Seawater desalination method and apparatus combining forward osmosis, precipitation and reverse osmosis
CN110759570A (en) Treatment method and treatment system for dye intermediate wastewater
CN106904777A (en) The processing method of full alkali short route energy-conservation saliferous industrial wastewater high
WO2019004281A1 (en) Water treatment device and water treatment method
JP6735830B2 (en) Membrane filtration method and membrane filtration system
JP2014184403A (en) Water treatment apparatus
JP7212490B2 (en) Water treatment device and water treatment method
JP7168739B2 (en) Water treatment device and water treatment method
CN110002654A (en) A kind of high-salt wastewater discharge treating system
JP7228492B2 (en) Water treatment device and water treatment method
US20150158748A1 (en) Process for treating concentrated brine
CN212403765U (en) System device for concentrating saline water and extracting water by using organic aqueous solution
TWI771476B (en) Processing device and processing method for silica-containing water
JP7306074B2 (en) Ultrapure water production device and ultrapure water production method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22739387

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 22739387

Country of ref document: EP

Kind code of ref document: A1