WO2022153980A1 - Dispositif et procédé de traitement des eaux - Google Patents

Dispositif et procédé de traitement des eaux 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
English (en)
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/ja
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/fr

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 Of Suspended Particles By Flocculating Agents (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

Le but de la présente invention est d'améliorer le taux de récupération de l'eau tout en supprimant la génération de tartre dans le cas de l'extraction de l'eau provenant d'une eau cible de traitement comprenant des impuretés. Ce dispositif de traitement des eaux comprend : une pluralité de parties de floculation et de sédimentation pour floculer et éliminer au moins une partie des impuretés de l'eau cible de traitement ; et une pluralité de parties d'extraction d'eau comportant chacune une membrane d'osmose directe et/ou une membrane d'osmose inverse pouvant extraire l'eau d'une solution contenant de l'eau, renfermant de l'eau comme solvant, de manière à extraire l'eau osmosée de l'eau cible de traitement, et qui évacuent également l'eau concentrée obtenue à la suite de l'extraction de l'eau osmosée de l'eau cible de traitement. Dans la direction d'écoulement de l'eau cible de traitement, une première partie d'extraction d'eau est disposée à l'étage situé en aval d'une première partie de floculation et de sédimentation, une seconde partie de floculation et de sédimentation est disposée à l'étage situé en aval de la première partie d'extraction d'eau, et une seconde partie d'extraction d'eau est disposée à l'étage situé en aval de la seconde partie de floculation et de sédimentation. La seconde partie d'extraction d'eau extrait l'eau osmosée de l'eau concentrée évacuée de la première partie d'extraction d'eau, et évacue l'eau hautement concentrée qui est obtenue en concentrant davantage l'eau concentrée évacuée de la première partie d'extraction d'eau, tandis que la première partie de floculation et de sédimentation et la seconde partie de floculation et de sédimentation floculent et éliminent au moins une partie de la silice.
PCT/JP2022/000583 2021-01-13 2022-01-11 Dispositif et procédé de traitement des eaux WO2022153980A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2021003270 2021-01-13
JP2021-003270 2021-01-13
JP2021-139894 2021-08-30
JP2021139894A JP7168739B2 (ja) 2021-01-13 2021-08-30 水処理装置および水処理方法

Publications (1)

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

Family

ID=82446277

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/000583 WO2022153980A1 (fr) 2021-01-13 2022-01-11 Dispositif et procédé de traitement des eaux

Country Status (1)

Country Link
WO (1) WO2022153980A1 (fr)

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 (fr) * 2012-04-11 2013-10-17 Ｊｆｅエンジニアリング株式会社 Procédé et dispositif de traitement de l'eau associée issue d'un puits
JP2014233699A (ja) * 2013-06-04 2014-12-15 水ｉｎｇ株式会社 被処理水からシリカを除去する方法及び装置
WO2015002309A1 (fr) * 2013-07-05 2015-01-08 三菱重工業株式会社 Système de traitement d'eau, procédé de traitement d'eau, installation de réfrigération et installation de production d'énergie électrique
WO2016147414A1 (fr) * 2015-03-19 2016-09-22 三菱重工業株式会社 Système de traitement d'eau et appareil de production d'énergie électrique
JP2016193435A (ja) * 2011-07-12 2016-11-17 高砂熱学工業株式会社 フラッシング排水の処理方法
JP2018079425A (ja) * 2016-11-16 2018-05-24 オルガノ株式会社 排水処理方法及び排水処理装置
JP2019171309A (ja) * 2018-03-29 2019-10-10 水ｉｎｇ株式会社 凝集沈殿装置及び凝集沈殿方法
JP2020058963A (ja) * 2018-10-05 2020-04-16 オルガノ株式会社 水処理装置および水処理方法

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016193435A (ja) * 2011-07-12 2016-11-17 高砂熱学工業株式会社 フラッシング排水の処理方法
WO2013153587A1 (fr) * 2012-04-11 2013-10-17 Ｊｆｅエンジニアリング株式会社 Procédé et dispositif de traitement de l'eau associée issue d'un puits
JP2014233699A (ja) * 2013-06-04 2014-12-15 水ｉｎｇ株式会社 被処理水からシリカを除去する方法及び装置
WO2015002309A1 (fr) * 2013-07-05 2015-01-08 三菱重工業株式会社 Système de traitement d'eau, procédé de traitement d'eau, installation de réfrigération et installation de production d'énergie électrique
WO2016147414A1 (fr) * 2015-03-19 2016-09-22 三菱重工業株式会社 Système de traitement d'eau et appareil de production d'énergie électrique
JP2018079425A (ja) * 2016-11-16 2018-05-24 オルガノ株式会社 排水処理方法及び排水処理装置
JP2019171309A (ja) * 2018-03-29 2019-10-10 水ｉｎｇ株式会社 凝集沈殿装置及び凝集沈殿方法
JP2020058963A (ja) * 2018-10-05 2020-04-16 オルガノ株式会社 水処理装置および水処理方法

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 (fr) Dispositif et procédé de traitement des eaux
JP6495207B2 (ja) 正浸透水処理のための逆行溶解度溶質の回収
CN104692574B (zh) 一种高含盐废水的处理方法
CN108218078B (zh) 一种含盐废水的处理方法及系统
US9266762B2 (en) Membrane filtration process with high water recovery
CN105000737B (zh) 一种工业污水处理系统及污水处理方法
WO2012120912A1 (fr) Système de production d'eau douce
JPWO2013153587A1 (ja) 坑井からの随伴水処理方法および装置
WO2013134710A1 (fr) Procédés pour la concentration osmotique de flux hypersalins
CN105800846A (zh) 一种用于反渗透浓水处理与零排放的方法与装置
CN105198141A (zh) 一种高温高盐废水的零排放方法
KR101344784B1 (ko) 정삼투법과 석출법 및 역삼투법을 조합한 해수담수화 방법 및 장치
CN110759570A (zh) 染料中间体废水的处理方法以及处理系统
WO2019004281A1 (fr) Dispositif de traitement d'eau et procédé de traitement d'eau
JP6735830B2 (ja) 膜ろ過方法及び膜ろ過システム
CN102815810B (zh) 脱盐系统和方法
JP7212490B2 (ja) 水処理装置および水処理方法
JP7168739B2 (ja) 水処理装置および水処理方法
CN106904777A (zh) 全碱短流程节能高含盐工业废水的处理方法
CN110002654A (zh) 一种高盐废水排放处理系统
JP7228492B2 (ja) 水処理装置および水処理方法
WO2015087142A1 (fr) Procédé de traitement de saumure concentrée
CN212403765U (zh) 一种利用有机水溶液浓缩盐水并提取水的系统装置
JP7306074B2 (ja) 超純水製造装置及び超純水製造方法
JP7149129B2 (ja) シリカ含有水の処理方法および処理装置

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