WO2009119300A1 - Procédé de prétraitement employant une membrane d'osmose inverse pour séparation d'eau à traiter - Google Patents

Procédé de prétraitement employant une membrane d'osmose inverse pour séparation d'eau à traiter Download PDF

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Publication number
WO2009119300A1
WO2009119300A1 PCT/JP2009/054463 JP2009054463W WO2009119300A1 WO 2009119300 A1 WO2009119300 A1 WO 2009119300A1 JP 2009054463 W JP2009054463 W JP 2009054463W WO 2009119300 A1 WO2009119300 A1 WO 2009119300A1
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Prior art keywords
water
alkali
treated
reverse osmosis
membrane
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PCT/JP2009/054463
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English (en)
Japanese (ja)
Inventor
康弘 松井
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メタウォーター株式会社
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Priority to JP2010505515A priority Critical patent/JP5489982B2/ja
Publication of WO2009119300A1 publication Critical patent/WO2009119300A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
    • C02F5/02—Softening water by precipitation of the hardness
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/0012—Settling tanks making use of filters, e.g. by floating layers of particulate material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/0039—Settling tanks provided with contact surfaces, e.g. baffles, particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/01—Separation of suspended solid particles from liquids by sedimentation using flocculating agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/24—Feed or discharge mechanisms for settling tanks
    • B01D21/245—Discharge mechanisms for the sediments
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/30—Control equipment
    • B01D21/305—Control of chemical properties of a component, e.g. control of pH
    • 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
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • 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
    • C02F1/24—Treatment of water, waste water, or sewage by flotation
    • 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
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by 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
    • 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
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage

Definitions

  • the present invention relates to a pretreatment method for water to be used for membrane filtration of seawater and other water to be treated with a reverse osmosis membrane.
  • a microfiltration membrane or an ultrafiltration membrane When seawater or other treated water is subjected to membrane filtration with a reverse osmosis membrane, a microfiltration membrane or an ultrafiltration membrane is generally installed in the preceding stage. However, if the treated water is passed through the microfiltration membrane or ultrafiltration membrane without treatment, calcium and magnesium, etc. that are dissolved in the treated water and may form scale, floating substances, Microfiltration membranes and ultrafiltration membranes are clogged in a short time by organic substances, and continuous membrane filtration operation cannot be performed. Therefore, these are removed in advance before the microfiltration membrane and the ultrafiltration membrane to reduce the burden on the microfiltration membrane and the ultrafiltration membrane.
  • the organic film is inferior in acid resistance, when cleaning the causative substance of film fouling adhering to the film surface, it cannot be cleaned in a short time by immersing the film in strong acid, and the weak acid solution There was a problem that it was necessary to wash the film by immersing it in it for a long time.
  • Japanese Patent Application Laid-Open No. 2000-24673 introduces seawater to a fluidized calcium removal apparatus including a crystallization reaction tank and a treated water introduction tank, adds alkali, and removes calcium in the crystallization reaction tank. Thereafter, a pretreatment method for separation of seawater with a reverse osmosis membrane is disclosed, in which after coagulation precipitation is performed in a coagulation tank, solid-liquid separation is performed in a sand filtration device. In the method of Japanese Patent Laid-Open No.
  • the object of the present invention is to solve the above-mentioned problems of the prior art, perform membrane filtration at a much higher flux than before, and separate and remove floating substances and organic substances more reliably than before. Then, it is providing the pre-processing method for reverse osmosis membrane separation which can reduce the burden of a reverse osmosis membrane of a back
  • the reverse osmosis membrane separation can be used for various purposes including seawater desalination.
  • the pretreatment method for reverse osmosis membrane separation of the water to be treated according to the present invention made to solve the above-mentioned problems is performed by adding an alkaline agent to the water to be treated and adjusting the pH to 9.0 or more.
  • the components dissolved in the water to be treated and capable of forming scales are precipitated as insoluble substances, and a part of the precipitates produced by the alkali agglomeration operation is settled and separated, and then the pH is 9.0 or more.
  • the flocs are formed by adding the flocculant while maintaining the environment, and using the remaining precipitates as agglomeration nuclei, followed by filtration using an alkali-resistant and acid-resistant filter body to form a scale.
  • the floating substances and organic substances in the water to be treated are also taken into the floc and removed. That is, according to the pretreatment method of the present invention, floating substances and organic substances are removed from the water to be treated together with calcium and magnesium. Therefore, it is possible to reduce the filtration resistance in the subsequent filter body in the aggregation step. Further, according to this pretreatment method, it is possible to remove calcium, magnesium, floating substances and organic substances from the water to be treated, and to reduce the burden on the reverse osmosis membrane in the subsequent stage of the filter body.
  • alkaline aggregation is an operation sometimes referred to as alkali coagulation, and refers to the addition of an alkali agent to precipitate calcium and magnesium.
  • aggregation simply refers to forming flocs using a flocculant.
  • a filter refers to a membrane or non-membrane filter medium having a pore diameter of 2 nm or more and 10 ⁇ m or less, and is a concept including a filtration membrane.
  • the alkali-resistant and acid-resistant filter is a ceramic filter, and has a flux of 6 m 3 / m 2 / day or more. It is preferable to filter with a membrane.
  • Membrane filtration flux may be 6 m 3 / m 2 / day or more if a strong ceramic filter body is used as an alkali and acid resistant filter body compared to organic filter bodies. Because it can. And by increasing the membrane filtration flux, the membrane area required for filtration after alkali flocculation and flocculation using a flocculating agent can be reduced compared to organic membranes, and the pretreatment equipment can be made more compact Because it becomes possible.
  • ASTM Standard Test Method for Silent Density Index of Water D4189-95
  • SDI 15 (1-T 0 / T 15 ) ⁇ 100/15 T 0 : Time (seconds) required to filter 500 ml of the initial sample when the sample is filtered at a pressure of 206 kPa using a membrane filter having a pore diameter of 0.45 ⁇ m and a diameter of 47 mm T 15 : The time (seconds) required to filter 500 ml of the sample after 15 minutes of filtration
  • water to be treated with a large SDI has a tendency to increase the filtration resistance, and the microfiltration membrane or the like is blocked earlier.
  • the SDI value of the water supplied to a reverse osmosis membrane is 4 or less.
  • an acid having a pH of 2 or less is used against fouling accompanied by an increase in membrane pressure difference of the alkali-resistant and acid-resistant filter. It is preferable to perform acid cleaning of the filter body. This is because by performing acid cleaning of the filter using a strong acid having a pH of 2 or less, such as hydrochloric acid, scales accumulated on the filter surface of the filter and iron-based fouling substances can be quickly eluted. And by eluting scales and fouling substances promptly, it is possible to shorten the time required for acid cleaning and increase the operating rate of the pretreatment equipment. In addition, since the filter body which comprises this invention has acid resistance, a filter body is not damaged by the acid washing by strong acid below pH2.
  • ferric chloride which exhibits a high coagulation effect in the alkaline region of pH 9.0 to 11, is used as the coagulant, precipitates generated as a result of alkali coagulation are used as coagulation nuclei to effectively float floating substances and organic substances. It is because it can be made.
  • the alkali aggregation operation is performed using an upward flow contact method.
  • an upward flow method in which the water to be treated and the alkaline agent flow upward, the alkali agent and the nuclear particles having a specific gravity greater than that of the water to be treated are brought into contact with the alkaline agent, the alkali-aggregated core particles and the water to be treated.
  • An example of a pretreatment method for reverse osmosis membrane separation of water to be treated according to the present invention includes, as shown in FIG. 1, an alkali flocculation step using an alkali flocculation device 1, a flocculation step using a flocculation mixing tank 2, A membrane filtration step using a filter body (ceramic membrane) 3 having alkali resistance and acid resistance.
  • seawater can be mentioned as the to-be-processed water processed by an example of this pre-processing method.
  • Seawater, pH 8 before and after, the hardness Ca 2+ concentration of about 20 meq / L has a high water.
  • the water to be treated (seawater) is introduced and the alkali agent is injected, and the seawater and the alkali agent are mixed.
  • the introduction of seawater as water to be treated is performed at the lower part of the alkali flocculation apparatus 1, and the alkali agent is injected at the upper part of the alkali flocculation apparatus 1.
  • seawater and an alkaline agent are mixed using an upward flow contact method. That is, in the alkali aggregating apparatus 1, seawater extruded from the lower part and an alkaline agent having a large specific gravity to be settled from the upper part efficiently come into contact with each other.
  • NaOH slaked lime Ca (OH) 2 , sodium carbonate (Na 2 CO 3 ), or the like
  • the reason why calcium carbonate crystallizes in this way is that the solubility of calcium carbonate decreases due to an increase in pH and becomes supersaturated, and a part of dissolved calcium in seawater becomes insoluble.
  • a treatment operation for causing such a reaction to the treated water is referred to as an alkali agglomeration operation.
  • a mixing method of the water to be treated and the alkaline agent in the alkali aggregating apparatus 1 in addition to the upward flow method, a water flow stirring method in which a multistage bypass wall is provided, a stirring blade or the like in the device, and the like. You may use the mechanical stirring system which provides a stirring means.
  • the addition amount of the alkaline agent in the alkali flocculation apparatus 1 is set so that the pH of the effluent water from the alkali flocculation apparatus 1 is 9.0 or more.
  • the pH of the effluent water is less than 9.0, precipitation and flocculation of calcium and magnesium in the alkali flocculation apparatus 1 become insufficient, and calcium and magnesium dissolved in water to be treated having high hardness such as seawater are supersaturated.
  • the alkali flocculation apparatus 1 and the flocculation / mixing tank 2 reach the subsequent stage filter in the state.
  • the water to be treated whose pH is set to 9.0 or more by the alkali flocculation in the alkali flocculation apparatus 1 flows down into the flocculation mixing tank 2. Therefore, in the flocculation mixing tank 2, a flocculating agent that exhibits a flocculating effect in this environment is added to the water to be treated.
  • an aggregating agent for example, ferric chloride is used.
  • flocs are formed in which fine particles precipitated by alkali flocculation in the alkali flocculation apparatus 1 are formed as flocculation nuclei.
  • floating substances or organic substances in the water to be treated are taken into the floc.
  • seawater since seawater has low turbidity, a sufficient coagulation effect cannot be obtained even if the coagulant is directly injected. Therefore, it is effective to form aggregated nuclei by performing alkali aggregation before the aggregation process as in the present invention.
  • the water to be treated that has passed through the flocculation / mixing tank 2 is sent to the alkali- and acid-resistant filter body 3 and subjected to membrane filtration.
  • the alkali-resistant and acid-resistant filter body 3 for example, a ceramic monolith membrane having a membrane pore diameter of 0.1 ⁇ m can be used.
  • the membrane shape of the filter body 3 is not necessarily limited to the monolith membrane, and may be a flat membrane or a tubular membrane.
  • floating substances and organic substances are membrane-separated by the alkali- and acid-resistant filter 3.
  • the membrane filtered water obtained by filtration with the filter body 3 has an SDI of about 3.0, and can be supplied to the reverse osmosis membrane.
  • the inflowing water flowing into the alkali-resistant and acid-resistant filter 3 has a certain degree of hardness reduced by the alkali flocculation process in the alkali flocculation apparatus 1 and the flocculation process in the flocculation mixing tank 2, but it still generates scale. Is remaining and is alkaline. Therefore, it is inevitable that a scale such as calcium carbonate is formed on the filtration surface of the alkali-resistant and acid-resistant filter body 3 by membrane filtration of the influent water. For this reason, if the filtration operation is continued, the membrane surface of the alkali-resistant and acid-resistant filter body 3 is agglomerated by the addition of ferric chloride in the agglomeration and mixing tank 2 due to this scale formation. Things derived from things (floc) gradually accumulate as fouling substances.
  • the alkali-resistant and acid-resistant filter body 3 is periodically acid-washed according to the increase in the membrane differential pressure due to the accumulation of fouling substances.
  • this acid cleaning accumulated fouling substances are dissolved and removed.
  • the filter body 3 used in the present invention is excellent in acid resistance, there is no film deterioration even when acid cleaning with a known strong acid having a pH of 2 or less is performed. Therefore, membrane fouling can be eliminated in a short time by acid cleaning using a strong acid having a pH of 2 or lower.
  • stable operation over a long period of time is possible while quickly recovering the increase in membrane differential pressure. That is, according to the present invention, the quality of the pretreated water does not deteriorate for a long time.
  • FIG. 2 shows a first embodiment of a pretreatment apparatus used in a pretreatment method for reverse osmosis membrane separation of water to be treated according to the present invention.
  • the pretreatment device of the first embodiment includes a flocculation / separation device 10 and a filter body 22. And the water (pretreatment water) processed with this pretreatment apparatus is filtered with the reverse osmosis membrane which is not illustrated, and is separated into permeated water and concentrated water.
  • the water to be treated to be treated by this pretreatment device for example, high-hardness water having a total hardness concentration of 300 mg / L (CaCO 3 equivalent concentration) or more, such as seawater or brine.
  • the total hardness concentration can be determined by calculating the sum of calcium and magnesium concentrations in water using ICP emission spectroscopic analysis in accordance with JIS K0101.
  • the aggregating and separating apparatus 10 has a cylindrical shape, and the water to be treated can flow between the alkali aggregating tank 11, the aggregating and sedimenting tank 12 provided above the alkali aggregating tank 11, and the alkali aggregating tank 11 and the agglomerating and sedimenting tank 12. And a partition plate 15 for partitioning.
  • the alkali flocculation tank 11 corresponds to the alkali flocculation apparatus 1 of the above example
  • the flocculation settling tank 12 corresponds to the flocculation mixing tank 2 of the above example.
  • the alkali agglomeration tank 11 is provided with a treated water inlet 13 as treated water injection means and an alkaline inlet 14 as alkaline agent injection means.
  • the water to be treated that has flowed from the water to be treated inlet 13 and the alkali agent injected through the alkali inlet 14 come into contact with each other, and the water is stirred in an upward flow. That is, an upward flow contact method is realized. Therefore, in the alkali flocculation tank 11, the pH of the water to be treated is increased, and calcium and magnesium in the water to be treated are precipitated as white turbid substances (carbonates or hydroxides).
  • an alkaline agent sodium hydroxide, sodium carbonate, etc.
  • water flow stirring refers to stirring using the flow (water flow) itself of water flowing into the apparatus, not mechanical stirring using a stirrer or the like. Specifically, by setting the cross-sectional area of the tank with respect to the design inflow of the water to be treated and the alkaline agent so that the Reynolds number, which is an indicator of hydraulic disturbance in the tank, is 10,000 or more, Water agitation can be realized. If it does in this way, the pre-process of high hardness raw
  • the partition plate 15 has a plurality of nozzles 16 protruding toward the coagulation sedimentation tank 12 side. Then, the water to be treated and the cloudy substance precipitated in the alkali coagulation tank 11 flow from the alkali coagulation tank 11 to the coagulation sedimentation tank 12 through the nozzle 16.
  • a coagulant injection port 18 as a coagulant injection means, a water outlet to be treated, and a stirrer 21 are provided in the upper part of the coagulation sedimentation tank 12.
  • the sludge discharge port 20 is provided in the upper part of the coagulation sedimentation tank 12.
  • a coagulant such as ferric chloride with respect to the mixture of the water to be treated and the cloudy substance flowing from the alkali coagulation tank 11 has a concentration of, for example, 1 to 6 mg / L (iron equivalent) ) And mixed.
  • the white turbid substance flowing in from the alkali flocculation tank 11 flows from the lower part to the upper part of the flocculation settling tank 12 and comes into contact with the flocculant added at the upper part to form a floc, but a part of the white turbid substance flows to the upper part. Settling in between. In this floc formation process, floating substances and organic substances contained in the water to be treated are also taken into the floc.
  • a part of the floc formed by adding the flocculant settles in the flocculent sedimentation tank 12 and accumulates in the accumulating portion 17 on the partition plate 15 together with the cloudy substance that settles while flowing from the lower part to the upper part of the flocculent sedimentation tank 12. .
  • the accumulated floc and cloudy substance are periodically withdrawn from the sludge discharge port 20 as a mud discharge means.
  • it can be appropriately discharged by intermittently opening or closing a gate valve (not shown) provided on the rear stage side of the sludge discharge port 20 or by continuous opening.
  • waste mud may be performed using a water head difference, and may be performed using a drainage pump.
  • the filter body 22 provided in the back
  • FIG. Therefore, pretreatment water from which components (calcium and magnesium), floatable substances and organic substances that may form a scale can be obtained by sedimentation separation in the flocculation separation apparatus 10 and filtration through the filter 22 can be obtained.
  • the filter body 22 for example, an alkali-resistant and acid-resistant microfiltration membrane or an ultrafiltration membrane can be used.
  • FIG. 3 shows a second embodiment of the pretreatment apparatus used in the pretreatment method for reverse osmosis membrane separation of water to be treated according to the present invention.
  • the pretreatment device of the second embodiment includes a flocculation / separation tank 30 having an alkali flocculation tank and a flocculation / mixing tank, and a filter body 36. And the water (pretreatment water) processed with this pretreatment apparatus is filtered with the reverse osmosis membrane which is not illustrated, and is separated into permeated water and concentrated water.
  • the flocculation / separation tank 30 includes a treated water storage tank 31, an alkali flocculation tank 32, and an agglomeration mixing tank 33. It communicates with. Therefore, the water to be treated that has flowed into the flocculation / separation tank 30 is stored in the water to be treated 31 and then flows from the lower part of the water to be treated 31 into the alkali flocculation tank 32.
  • the alkali flocculation tank 32 corresponds to the alkali flocculation apparatus 1 of the above example
  • the flocculation mixing tank 33 corresponds to the flocculation / mixing tank 2 of the above example.
  • the alkali flocculation tank 32 in this embodiment includes a stirrer 34.
  • an alkali agent such as sodium hydroxide is added to the water to be treated, and the water to be treated and the alkali agent are mixed by the stirrer 34.
  • pH of to-be-processed water rises and calcium and magnesium in to-be-processed water precipitate as a cloudy substance (carbonate or hydroxide).
  • the injection amount of the alkaline agent can be adjusted by a known means so that the pH of the water flowing out from the coagulation / separation tank 30 becomes 9.0 or more.
  • the cloudy substance precipitated in the alkali flocculation tank 32 is settled and separated in the alkali flocculation tank 32.
  • the cloudy substance that has not settled in the alkali coagulation tank 32 and the water to be treated flow into the coagulation mixing tank 33 from the lower part of the alkali coagulation tank 32.
  • a coagulant such as ferric chloride is added to the water to be treated and the cloudy substance flowing from the alkali coagulation tank 32, and the water to be treated, the cloudy substance and the flocculant are mixed by the stirrer 35.
  • the cloudy substance aggregates to form flocs by the addition of the flocculant.
  • floating substances and organic substances contained in the water to be treated are also taken into the floc.
  • pretreatment water from which components (calcium and magnesium), floatable substances and organic substances that may form scales are removed is obtained by sedimentation separation in the alkali coagulation tank 32 and filtration in the filter body 36.
  • a ceramic membrane can be used as the filter body 36.
  • a membrane having acid resistance is used as the filter body. Therefore, when the filter body is clogged, the pH is 2 or less. Can be washed with strong acid. That is, in the pretreatment devices of the first and second embodiments, fouling can be eliminated in a short time.
  • Example 1 Seawater having a pH of around 8 was treated using the pretreatment apparatus shown in FIG. Specifically, seawater was caused to flow through the flocculation / separation apparatus 10 in FIG. 2 in an upward flow with a linear velocity of 10 m / hr or more, and NaOH was added to the seawater as an alkaline agent. And the alkali aggregation was performed on the conditions from which pH of the seawater after alkali agent addition was set to 9.0 or more. Thereafter, ferric chloride as a coagulant is 1 to 6 mg / L (converted value of iron) into seawater (total dissolved component (TDS) concentration 3.5%) introduced into the coagulation sedimentation tank 12 through the alkali coagulation tank 11. As)).
  • ferric chloride as a coagulant is 1 to 6 mg / L (converted value of iron) into seawater (total dissolved component (TDS) concentration 3.5%) introduced into the coagulation sedimentation tank 12 through the alkali coagulation tank 11. As)).
  • the seawater to which the flocculant was added was filtered through a ceramic monolith membrane 3 (microfiltration ceramic membrane) having a membrane pore diameter of 0.1 ⁇ m.
  • the filtration flux at that time was 6 to 8 m 3 / m 2 / day, and no increase in the differential pressure exceeding 100 KPa was observed even after 2000 hours.
  • the TDS can be determined by measuring the weight of the residue when the sample (seawater) is heated at 110 ° C. to remove moisture.
  • Example 2 Using the apparatus shown in FIG. 3, seawater was treated by changing the pH after the alkali flocculation operation. Specifically, when seawater is treated with a membrane filtration flux of 7 m 3 / m 2 / day, the change in transmembrane pressure difference between the case where the pH after alkali aggregation is 7.8 and the case where it is 9.5. was measured. The same flocculant as that used in Example 1 was used. The transmembrane pressure difference was determined by measuring the operating pressure on the primary side and the secondary side of the membrane with a pressure gauge and calculating the difference. The results are shown in FIG.

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

Abstract

L’invention concerne un procédé de prétraitement pour séparation employant une membrane d'osmose inverse. Dans ledit procédé, une filtration sur membrane peut être réalisée à une vitesse d'écoulement de loin supérieure à celles obtenues avec les procédés classiques, et les matières solides en suspension et les substances organiques peuvent être séparées/éliminées plus efficacement qu'avec les procédés classiques, ce qui atténue les contraintes devant être subies par une membrane d'osmose inverse à une étape ultérieure. Le procédé de prétraitement se caractérise par: l'adjonction d'un alcali à l'eau brute à traiter et le réglage du pH de cette dernière à une valeur d'au moins 9,0 pour précipiter, en tant que substance insoluble, un constituant dissous dans l'eau brute et susceptible de former un dépôt de tartre; la décantation et la séparation d'une partie du précipité généré par la floculation de l'alcali; l'adjonction subséquente d'un floculant à l'eau avec maintien des conditions de pH à la valeur d'au moins 9,0 pour former des flocons avec le précipité restant utilisé comme noyau de floculation; puis la filtration de l'eau à travers un milieu filtrant résistant aux alcalis et aux acides afin d'éliminer le constituant susceptible de former un dépôt de tartre, les matières solides en suspension et les substances organiques.
PCT/JP2009/054463 2008-03-24 2009-03-09 Procédé de prétraitement employant une membrane d'osmose inverse pour séparation d'eau à traiter WO2009119300A1 (fr)

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Cited By (10)

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JP2010253424A (ja) * 2009-04-27 2010-11-11 Nishimatsu Constr Co Ltd 濁水浄化処理システム
JP2012061402A (ja) * 2010-09-15 2012-03-29 Toshiba Corp 淡水化システム
JP2013104723A (ja) * 2011-11-11 2013-05-30 Kurita Water Ind Ltd Ｓｒ含有水の処理方法及び処理装置
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JP2012061402A (ja) * 2010-09-15 2012-03-29 Toshiba Corp 淡水化システム
JP2013104723A (ja) * 2011-11-11 2013-05-30 Kurita Water Ind Ltd Ｓｒ含有水の処理方法及び処理装置
JP2013202582A (ja) * 2012-03-29 2013-10-07 Kurita Water Ind Ltd カルシウム・マグネシウム含有水の処理方法及び処理装置
JP2014144433A (ja) * 2013-01-29 2014-08-14 Panasonic Corp ホウ素含有排水処理方法およびホウ素含有排水処理システム
JP2016187791A (ja) * 2015-03-30 2016-11-04 栗田工業株式会社 カルシウムイオン及び無機炭素含有水の処理方法
JPWO2017154624A1 (ja) * 2016-03-09 2019-01-10 住友電気工業株式会社 高硬度排水の処理方法
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TWI711587B (zh) * 2016-03-09 2020-12-01 日商住友電氣工業股份有限公司 高硬度排水之處理方法
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JPWO2017159303A1 (ja) * 2016-03-14 2019-01-17 住友電気工業株式会社 高硬度排水の処理方法
TWI711588B (zh) * 2016-03-14 2020-12-01 日商住友電氣工業股份有限公司 高硬度排水之處理方法
JP2017170275A (ja) * 2016-03-18 2017-09-28 栗田工業株式会社 高アルカリ度水中のカルシウム除去方法
CN106362515B (zh) * 2016-11-25 2018-08-21 鲁东大学 一种可净化空气中雾霾的微孔炭-金属复合膜制备方法
CN106362515A (zh) * 2016-11-25 2017-02-01 鲁东大学 一种可净化空气中雾霾的微孔炭‑金属复合膜制备方法

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