JP2006204977A - Method and apparatus for treating biologically treated water-containing water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably treat biologically treated water-containing water over a long period when purifying it by RO membrane separation treatment by preventing lowering of a permeating flow bundle through an RO membrane, and to dispense with addition of an expensive slime control agent to RO membrane feed water. <P>SOLUTION: In this treatment method of biologically treated water-containing water, water to be treated containing biologically treated water is brought into contact with chelate resin to remove metal ions, then pH is adjusted to 9.5 or more to be subjected to reverse osmosis membrane separation treatment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and an apparatus for treating biologically treated water-containing water, and more specifically, the permeation flux of RO membranes when water containing biologically treated water of wastewater is subjected to membrane separation treatment by a reverse osmosis (RO) membrane. It is related with the processing method and processing apparatus of the biological treatment containing water which can prevent the fall of this and can perform a stable process over a long period of time.

  In recent years, environmental standards and water quality standards tend to be stricter, and it is desired that effluent water be highly purified. On the other hand, in order to recover and reuse various wastewaters for the purpose of eliminating water shortage, advanced water treatment is desired.

  Under such circumstances, RO membrane separation treatment has been used in many fields in recent years because it can effectively remove impurities such as ions, organic substances, and fine particles in water. It was. For example, when high-concentration TOC or low-concentration TOC wastewater containing acetone, isopropyl alcohol, etc. discharged from a semiconductor manufacturing process is recovered and reused, this is first biologically treated to remove TOC components, A method of purifying by RO membrane separation treatment is widely adopted (for example, Patent Document 1).

  Conventionally, as the RO membrane used for the RO membrane separation treatment, generally aromatic cross-linked polyamide composite membrane (PA membrane), cellulose acetate (CA membrane) and the like are provided. In RO membrane separation processing, in order to prevent permeation flux (Flux) from decreasing and perform stable treatment, there is a standard for water to be treated (water supply for RO membrane separation processing) supplied to the RO membrane separation device. The fouling index (FI) defined in JIS K 3802 is desired to be 4 or less. The smaller the value of the fouling index, the less the load on the RO membrane and the lower the permeation flux is less likely to occur.

  Among conventional RO membranes, PA membranes are contaminated with trace amounts of fouling substances such as surfactants, glycolipids, and proteins contained in the water to be treated, and the permeation flux rapidly decreases. There is a drawback that stable RO membrane separation treatment cannot be continued. The CA membrane has better contamination resistance than the PA membrane, but has a problem that the desalination rate is low and the operation pressure is high.

  In recent years, anti-contamination membranes have been developed as RO membranes that have made membranes less soilable by eliminating the chargeability of the membrane surface and improving hydrophilicity. Even with such anti-contamination membranes, When treating water containing relatively high viscosity components such as high molecular polysaccharides (glycolipids) and proteins, the contamination resistance is low, and the permeation flux decreases over time. is there.

  Conventionally, as for urine wastewater, as a wastewater treatment device that can improve the quality of treated water with less clogging of the membrane, without significantly reducing the amount of permeate, and significantly extending the operating life of the membrane, A means for dewatering system wastewater, a means for biologically nitrifying and denitrifying the separated water from the dewatering means, a means for coagulating the biological treatment liquid from the nitrifying and denitrifying means, and a solid-liquid separation of the aggregating treatment liquid from the aggregating means An apparatus for treating sewage sewage comprising means for performing membrane separation without any treatment has been proposed (Patent Document 2). In addition, when water containing a small amount of organic substances is treated by biological treatment with oligotrophic bacteria and membrane separation treatment, a method of performing stable and efficient treatment for a long period of time by preventing a decrease in the permeation flux of the membrane. A method for maintaining the dissolved oxygen concentration in the biological reaction tank at 2 mg / L or more has been proposed (Patent Document 3).

  In order to prevent clogging of the membrane in the RO membrane separation treatment of the biological treatment-containing water, it is conceivable to remove by filtration in advance a relatively high-fouling substance such as a protein or a polymer polysaccharide. However, since these fouling substances are very small, they are not captured by a filter such as a gravity filter or a pressure filter. Inflow and cause clogging of the membrane. When membrane filtration is performed with a microfiltration membrane device having a pore size of 0.45 μm or less, the fouling index of the membrane filtration water obtained is 4 or less, and the water supply conditions to the RO membrane are satisfied. In recent years, it has become clear that the decrease in permeation flux cannot be suppressed.

By the way, in general, in RO membrane separation treatment, a slime control agent is added to the RO membrane water supply in order to prevent membrane contamination caused by the growth of microorganisms in the RO membrane separation device and decrease in permeation flux due to membrane contamination. However, since the slime control agent is expensive, it is desired to prevent the growth of microorganisms in the RO membrane separation apparatus without adding such a slime control agent.
JP 2002-336886 A Japanese Patent Publication No. 7-55318 JP 2000-288578 A

  In the present invention, when water containing biologically treated water is subjected to membrane separation treatment using an RO membrane, the permeation flux of the RO membrane can be prevented from being lowered, and stable treatment can be performed over a long period of time. It aims at providing the processing method and processing apparatus of the biological treatment water containing water which can make the addition of the slime control agent to feed water unnecessary.

  In the method for treating biologically treated water-containing water of the present invention (Claim 1), the treated water containing biologically treated water is contacted with a chelate resin to remove metal ions, and then the pH is adjusted to 9.5 or higher. And reverse osmosis membrane separation treatment.

  The method for treating water containing biologically treated water according to claim 2 is characterized in that, in claim 1, prior to bringing the water to be treated into contact with the chelate resin, the water to be treated is brought into contact with the cation exchange resin.

  The method for treating biologically treated water-containing water according to claim 3 is that in claim 1, prior to bringing the treated water into contact with the chelate resin, a carbonate compound is added to the treated water to remove the hardness component. Features.

  The apparatus for treating biological water containing biological treatment water according to the present invention (Claim 4) includes metal ion removing means for removing metal ions by bringing water to be treated containing biological treated water into contact with a chelate resin, and the metal ion removing means. PH adjusting means for adjusting the treated water to pH 9.5 or higher, and a reverse osmosis membrane separation apparatus into which the treated water of the pH adjusting means is introduced.

  According to a fifth aspect of the present invention, there is provided the biological treatment water-containing water treatment apparatus according to the fourth aspect, further comprising means for bringing the water to be treated introduced into the metal ion removing means into contact with a cation exchange resin.

  The biological treatment water-containing water treatment apparatus according to claim 6 is characterized in that in claim 1, the treatment apparatus includes means for removing a hardness component by adding a carbonate compound to the water to be treated introduced into the metal ion removal means. To do.

  According to the biological treatment water-containing water treatment method and treatment apparatus of the present invention, when the biological treatment water-containing water is purified by RO membrane separation treatment, a decrease in the permeation flux of the RO membrane can be prevented for a long period of time. High quality water can be efficiently obtained by performing stable treatment. Further, it is not necessary to add an expensive slime control agent to the RO membrane water supply.

  That is, as described above, by performing the filtration process prior to the RO membrane separation process of the RO membrane separation apparatus, water satisfying the RO water supply condition of the fouling index 4 or less can be obtained. There was a problem of time-lapse deterioration of the bundle. As a result of intensive studies on the cause of this problem, the inventors of the present invention have found that the polyvalent metal ions contained in the wastewater containing biologically treated water contain the RO membrane when the wastewater containing biologically treated water is used as the RO water supply. It has been found that it is a binder factor for fouling substances such as proteins and polymer polysaccharides that are causative substances, and causes the adhesion of contaminants to the film surface. It was.

  In the present invention, prior to the RO membrane separation treatment, the polyvalent metal ions are adsorbed and removed by the chelate resin to suppress the adhesion of such contaminants to the membrane surface, thereby allowing permeation due to membrane clogging. A decrease in flux can be prevented.

  That is, the chelate resin is capable of selectively adsorbing and removing polyvalent metal ions, and efficiently removes polyvalent metal ions even if monovalent cations are present in the water to be treated. Polyvalent metal ions that can act as binders for relatively sticky fouling substances such as proteins and polymer polysaccharides that are the main causative substances of RO membrane occlusion in biologically treated water-containing water Can be removed to a low level.

In particular, by removing most of the hardness component in the pretreatment by adding a cation exchange resin or a carbonate compound, the chelate resin removes the remaining hardness components (Ca ²⁺ ions, Mg ²⁺ ions, etc.) and other polyvalent metal ions. It is sufficient to remove the metal ions, and the load is reduced and the metal ions can be removed to a low level.

Further, in the present invention, the water from which metal ions have been removed in this way is adjusted to pH 9.5 or higher to provide RO membrane water supply, so the following effects are exhibited.
(1) Microorganisms cannot live in alkaline areas. Therefore, by adjusting the pH of the RO membrane water supply to 9.5 or higher, it is possible to create an environment where there are nutrients but microorganisms cannot live, and the addition of an expensive slime control agent as in the past is unnecessary. .
(2) It is known that fouling substances with relatively high tack, such as proteins and high molecular weight polysaccharides that are the main cause of RO membrane occlusion, are less likely to adhere to the membrane surface at pH 9.5 or higher. Therefore, by making the RO membrane water supply alkaline with a pH of 9.5 or higher, it is possible to more effectively suppress the membrane surface blockage in the RO membrane separation apparatus.

  In such a highly alkaline region, even if a small amount of polyvalent metal ions are present in the RO membrane water supply, for example, calcium ions, calcium-based scales such as calcium carbonate or calcium phosphate are deposited on the RO membrane surface. However, in the present invention, since the polyvalent metal ions in the raw water can be removed to a very low concentration with a chelate resin in advance, it is possible to suppress the precipitation of scale in such a highly alkaline region. Become.

  According to claims 2 and 5, by treating with a cation exchange resin prior to the removal of metal ions by the chelate resin, the load on the chelate resin is reduced, and the polyvalent metal ion adsorption efficiency by the chelate resin is increased and regenerated. The frequency can be reduced and stable processing can be performed for a long time.

  That is, when biologically treated water is directly treated with a chelate resin, the chelate resin saturates the adsorption capacity at an early stage, and therefore it is necessary to frequently regenerate it. Therefore, prior to treatment with the chelate resin, treatment with a cation exchange resin to remove most of the hardness components in advance increases the multivalent metal ion adsorption efficiency by the chelate resin and reduces its regeneration frequency. be able to.

  According to claims 3 and 6, prior to the treatment with the chelate resin, the carbonic acid compound is added to remove most of the hardness components in advance, and then the remaining metal ions are removed with the chelate resin, thereby reducing the load. This can be reduced to increase the polyvalent metal ion adsorption efficiency by the chelate resin, and to reduce the regeneration frequency of the chelate resin.

  Hereinafter, embodiments of the method and apparatus for treating biologically treated water-containing water according to the present invention will be described in detail.

  Biologically treated water-containing water to which the present invention is applied includes the manufacturing of electronic devices such as semiconductors and liquid crystals, the manufacturing of machinery such as automobiles and home appliances, the manufacture of industrial materials such as steel, cement, resins and films, soft drinks, and sake Wastewater from food processing industries such as dairy products, standard activated sludge method, anaerobic aerobic method, circulating nitrification denitrification method, oxidation ditch, batch activated sludge method, microorganism fixing method, watering Biological treatment obtained by anaerobic treatment such as fixed bed method such as filter bed method, rotating disk method, contact oxidation method, biological filtration method, biological deodorization method and anaerobic treatment such as anaerobic digestion method Examples thereof include water and wastewater containing these biologically treated water.

  The present invention is particularly applicable to biologically treated water-containing water such as organic carbon (TOC) -containing water discharged from semiconductor manufacturing processes and general wastewater (including domestic wastewater) into which this biologically treated water flows. It can be suitably applied.

  Although there is no restriction | limiting in particular in the quality of the biological treatment water containing water to which this invention is applied, It is preferable that a TOC density | concentration is 0.5-20 mg / L. The polyvalent metal ion concentration of the biologically treated water-containing water is 10 to 1000 mg / L, particularly 20 mg / L or more and 500 mg / L or less, and particularly preferably 100 mg / L or more.

  Here, the polyvalent metal ion concentration can be represented by the sum of calcium ions, magnesium ions, aluminum ions (soluble aluminum), and iron ions (dissolved iron).

  Biologically treated water-containing water to which the present invention is applied contains a large amount of polyvalent metal ions and significantly promotes organic matter contamination of the RO membrane. For example, an inorganic flocculant such as calcium chloride, PAC, iron chloride is added. It is preferable to contain the inorganic waste water etc. which performed the aggregation process. The biologically treated water-containing water to be treated in the present invention preferably has a calcium ion concentration of 50 mg / L or more, particularly 100 to 500 mg / L. The invention can be applied effectively.

  In the present invention, prior to such RO membrane separation treatment of biologically treated water-containing water, metal ions, particularly polyvalent metal ions, are removed by contacting with a chelate resin.

  As the chelate resin used here, any resin can be used as long as it is a metal-removing chelate resin. For example, a chelate resin in which an iminodiacetic acid group is bound to a crosslinked styrene substrate can be suitably used.

The method for contacting the chelate resin and the water to be treated is not particularly limited, and the water to be treated may be passed through a chelate resin tower filled with the chelate resin, and as shown in FIG. Water may be passed through an ion exchange tower in which a cation exchange resin and a chelate resin layer are formed. In this case, the water flow system to the chelate resin tower or the ion exchange tower may be either a downward flow or an upward flow, and there is no particular limitation on the tower type such as a fixed bed or a fluidized bed. Passing water SV is preferably 5~50hr ^-1, especially 10～30Hr ^-1 are preferred.

  Water from which metal ions in biologically treated water-containing water are adsorbed and removed with a chelate resin is then adjusted to pH 9.5 or higher, preferably pH 10-11 by adding an alkali such as NaOH, and then passed through an RO membrane separator. RO membrane separation treatment. Here, when the pH in the RO membrane water supply is less than 9.5, the effects (1) and (2) described above cannot be obtained effectively. Even if the adjusted pH is excessively high, a large amount of alkali is required, and a large amount of acid is required for pH adjustment after the RO membrane separation treatment.

  The RO membrane used for the RO membrane separation treatment is not particularly limited as long as it is excellent in alkali resistance such as polyetheramide composite membrane, polyvinyl alcohol composite membrane, aromatic polyamide membrane, etc. This is effective for a wholly aromatic cross-linked polyamide composite membrane in which the membrane is easily contaminated by adsorption of a trace amount of fouling substances such as surfactants, glycolipids, and proteins.

  RO membrane separation processing is not limited to one-stage processing using one RO membrane separation device, and RO membrane separation devices can be arranged in series in two or more stages to perform advanced processing by multi-stage RO membrane separation processing. It is.

  In the present invention, prior to such RO membrane separation treatment, metal ions are removed using a chelate resin so that the total polyvalent metal ion concentration of the feed water of the RO membrane separation device is 10 μg / L or less. It is preferable to make it. If the polyvalent metal ion concentration is higher than this range, the RO membrane may be scaled.

  Further, when the water recovery rate of the RO membrane separation device is increased, the polyvalent metal ions and the organic fouling substance are concentrated, and the binding and adhesion of the both to the membrane easily occur. Is preferably operated at a water recovery rate of 80% by weight or less, for example 60-80% by weight.

  In the present invention, metal ions may be removed with a cation exchange resin prior to removal of metal ions with a chelate resin. As this cation exchange resin, Na-type strong cation exchange resin or weak cation exchange resin is preferably used.

  The advantages of treating with a chelating agent after treating with Na type strong cation exchange resin are as follows.

  That is, in the H-type strong cation exchange resin, the treated water becomes acidic, so that the amount of alkali injection for adjusting the pH of the RO membrane water supply to 9.5 or higher in the subsequent stage increases. In addition, since the biologically treated water-containing water often contains a large amount of sodium ions, when H-type strong cation exchange resin is used, calcium or magnesium, which is a scale-generating factor, is used for sodium ions. Thus, the amount of adsorption of the hardness component must be reduced, and the regeneration process must be performed frequently. On the other hand, when the Na-type strong cation exchange resin is used, the pH of the treated water becomes neutral, and there is no problem of reducing the amount of hardness component adsorbed by sodium ions.

  However, even if the treatment is performed with a cation exchange resin, a hardness component of about several hundred μg / L to several mg / L always leaks. Therefore, after treatment with Na-type strong cation exchange resin, water is passed through a chelate resin excellent in selective adsorption performance for polyvalent metal ions to remove the hardness of polyvalent metal ions. It becomes possible to reduce polyvalent metal ions to an infinitely low level.

  Although it is possible to treat with a chelate resin after treating with an H-type strong cation exchange resin, the chelate resin has a lower adsorption capacity for hardness components on the acidic side. Will be more.

  Moreover, the advantage by processing with a chelate resin after processing with a weak cation exchange resin is as follows.

  The weak cation exchange resin, like the Na-type strong cation resin, has a neutral pH of the treated water, but the concentration of the hardness component leaking into the treated water is not sufficient to suppress the scale in the RO membrane separator. Absent. Therefore, after treating with a weak cation exchange resin, it is possible to reduce the hardness component from the biologically treated water-containing water to an infinitely low level by treating with a chelate resin having strong selectivity with polyvalent metal ions. .

The water passing through these resins is a method of passing water through a packed tower packed with Na-type strong cation or weak cation resin and then passing through the packed tower packed with a chelate resin, or collecting in the packed tower. There is a method in which a water plate is provided, and two kinds of resins are filled in the same packed tower to pass water. Such water passing SV to the packed column is preferably 5~50hr ^-1, 10~30hr ^-1 is more preferable. The water flow method is not particularly limited, such as downward flow, upward flow, fixed bed, fluidized bed.

  The resin regeneration method in this case is as follows.

  In the method of passing water through the Na-type strong cation exchange resin and then passing through the chelate resin, a method of sequentially regenerating the chelate resin and the Na-type strong cation exchange resin sequentially or using an aqueous NaCl solution; A method in which acid is used in order of Na type strong cation exchange resin and then regenerated to H type, and then converted to Na type using NaCl or NaOH; or after regenerating only chelate resin with acid, chelate resin, A method of converting to Na type using NaCl or NaOH in the order of Na type strong cation exchange resin may be mentioned.

  In the method of passing water through a weak cation exchange resin and then passing through a chelate resin, the acid is used to sequentially regenerate the chelate resin and the weak cation exchange resin in the order of H type, and then the chelate is used using NaCl or NaOH. A method in which only the resin is converted to Na type; or a method in which the weak cation exchange resin is acid and the chelate resin is individually regenerated with NaCl or NaOH.

  Examples of the regeneration method include cocurrent regeneration or countercurrent regeneration, but it is preferable to employ countercurrent regeneration because of its high regeneration efficiency.

  In the present invention, prior to the removal of metal ions by the chelate resin, the hardness component may be removed by adding a carbonic acid compound to the biologically treated water-containing water. That is, a carbonate compound may be added to biologically treated water-containing water to precipitate a hardness component such as calcium as a carbonate, which may be separated.

  In this case, carbonates such as calcium carbonate are precipitated by adding carbonates such as sodium carbonate and sodium hydrogen carbonate to the biologically treated water-containing water or blowing carbon dioxide. The precipitated metal carbonate is removed by a filtration device such as sand filtration, microfiltration, ultrafiltration, or nanofiltration. You may perform this filtration apparatus combining 2 or more. By such carbonate precipitation and filtration removal, the TOC component in the biologically treated water-containing water can also be removed. The addition amount of the carbonic acid compound is suitably equivalent to 3 to 3 equivalents of the metal ion to be removed. However, if a chelating agent or dispersant for the polyvalent metal ion is mixed, it is necessary to increase the amount used. There is. After the filtration of the metal carbonate, the residual carbonate component may be removed by adjusting the pH (pH 5 to 6.5) and / or aeration, if necessary.

  Thus, even if the metal ions in the biologically treated water-containing water are precipitated as carbonates and the precipitates are removed, the concentration of polyvalent metal ions in the treated water is usually about several mg / L to several tens mg / L. Therefore, in order to completely suppress scale generation in the RO membrane separation device, subsequent treatment with a chelate resin is required.

  In the method of the present invention, pressure filtration, gravity filtration, microfiltration, ultrafiltration, pressurized flotation, precipitation, etc. are performed before these metal ion removal means to remove suspended substances contained in the raw water. A pretreatment may be performed, and thereby an increase in the differential pressure in the chelate resin packed tower can be suppressed. Further, an activated carbon tower may be installed to adsorb and remove organic substances to reduce the TOC concentration of water flowing into the chelate resin packed tower and the RO membrane separation device.

  In FIG. 1, an example of embodiment of the processing apparatus of the biologically treated water containing water of this invention is shown. In FIG. 1, the biologically treated water-containing water is sent to the ion exchange tower 1, and in the ion exchange tower 1, it is sequentially treated with the cation exchange resin 1A and the chelate resin 1B to remove the metal ions contained in the biologically treated water-containing water. The The treated water of the ion exchange tower 1 is added with an alkali such as NaOH through the tank 2 and adjusted to pH 9.5 or higher, and then introduced into the RO membrane separation device 3 by the pump P and subjected to RO membrane separation treatment. The permeated water of the RO membrane separation device 3 is taken out as final treated water, and the concentrated water is subjected to evaporative concentration treatment or subjected to activated carbon treatment according to the water quality and then discharged into rivers and sewage.

  FIG. 1 shows an example of an embodiment of the present invention, and the present invention is not limited to the illustrated one as long as the gist thereof is not exceeded. That is, as described above, pretreatment means such as a filtration apparatus and an activated carbon tower may be provided in the front stage of the ion exchange tower, and the RO membrane separation apparatus may be provided in two or more stages. Furthermore, a chelate resin tower is provided instead of an ion exchange tower filled with a cation exchange resin and a chelate resin, and carbonate or carbon dioxide gas is added to biologically treated water-containing water as means for removing hardness components in the previous stage of the chelate resin tower. Then, a stirring tank for depositing metal carbonate and a filtration device for filtering water flowing out of the stirring tank may be provided.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

Example 1
As the biologically treated water-containing water, treated with the equipment shown in Fig. 1 using the combined wastewater treated with the organic filtration wastewater from the semiconductor factory and treated with the biological filter and the flocculated water containing hydrofluoric acid. Went. The total wastewater had a TOC concentration of 5 mg / L, a total hardness of 300 mg / L as CaCO ₃ , a Na ⁺ concentration of 200 mg / L, and a polyvalent metal ion concentration of 320 mg / L. This general waste water is passed through the Na-type strong cation exchange resin (“SKIB” manufactured by Mitsubishi Chemical Corporation) layer and the iminodiacetic acid-based chelate resin (“CR11” manufactured by Mitsubishi Chemical Corporation) layer sequentially with water SV30h- ^1. did.

  The quality of the treated water obtained was as shown in Table 1. After adding NaOH to this treated water and adjusting the pH to 10.5, using RO membrane separator (“ES-20” manufactured by Nitto Denko Corporation), operating pressure 0.75 MPa, water recovery rate 80 RO membrane separation treatment was performed under the condition of%.

  The time-dependent change of the permeation flux (Flux) of the RO membrane separation device at this time was examined, and the result is shown in FIG. The quality of the permeated water and concentrated water of the RO membrane was as shown in Table 1.

Comparative Example 1
The RO membrane water supply was adjusted to 7 and the RO membrane was separated under the same conditions as in Example 1 except that 3 mg / L of a slime control agent ("EC-503" manufactured by Kurita Kogyo Co., Ltd.) was added. The change over time in the permeation flux of the RO membrane separation apparatus was examined, and the results are shown in FIG.

Comparative Example 2
The RO membrane separation treatment was performed under the same conditions as in Example 1 except that the treatment with the chelate resin was not performed. The change with time in the permeation flux of the RO membrane separation device at this time was examined, and the results are shown in FIG.

Comparative Example 3
3 mg / L of slime control agent ("EC-503" manufactured by Kurita Kogyo Co., Ltd.) and 10 mg / L of hexametaphosphate scale dispersant ("Mizclean L401" manufactured by Kurita Kogyo Co., Ltd.) RO membrane separation treatment was performed under the same conditions as in Example 1 using water adjusted to pH 7 as RO membrane water supply. The change with time in the permeation flux of the RO membrane separation device at this time was examined, and the results are shown in FIG.

As is clear from FIG. 2, in Example 1 in which the RO membrane separation treatment was performed under high pH conditions after removing the metal ions, the permeation flux decreased more slowly than in Comparative Examples 1 to 3, and the flow of water started 60 After a time, a difference in permeation flux of about 0.2 to 0.4 m ³ / m ² · d was observed with respect to Comparative Examples 1 to ³ .

  In addition, in the comparative example 1, the gel-like organic substance and the calcium carbonate scale are attached to the RO membrane surface after the water flow, the calcium carbonate scale is attached in the comparative example 2, and the gel in the comparative example 3 In the example 1, almost no deposits were observed on the RO membrane surface.

It is a systematic diagram which shows embodiment of the processing apparatus of the biological treatment water containing water of this invention. It is a graph which shows the time-dependent change of the permeation | transmission flux of the RO membrane separation apparatus in Example 1 and Comparative Examples 1-3.

Explanation of symbols

1 Ion Exchange Tower 1A Cation Exchange Resin 1B Chelate Resin 2 Tank 3 RO Membrane Separator

Claims (6)

  Water to be treated containing biologically treated water is contacted with a chelating resin to remove metal ions, and then subjected to reverse osmosis membrane separation treatment by adjusting the pH to 9.5 or higher. Processing method.   The method for treating biological treatment water-containing water according to claim 1, wherein the water to be treated is brought into contact with a cation exchange resin before the water to be treated is brought into contact with the chelate resin.   The method for treating biological treatment water-containing water according to claim 1, wherein, prior to bringing the water to be treated into contact with the chelate resin, a carbonate compound is added to the water to be treated to remove a hardness component.   Metal ion removing means for removing metal ions by contacting treated water containing biologically treated water with a chelate resin, pH adjusting means for adjusting treated water of the metal ion removing means to pH 9.5 or higher, and the pH A treatment apparatus for water containing biologically treated water, comprising: a reverse osmosis membrane separation apparatus into which treated water of adjusting means is introduced.   The apparatus for treating biologically treated water-containing water according to claim 4, further comprising means for bringing water to be treated introduced into the metal ion removing means into contact with a cation exchange resin.   The treatment apparatus for water containing biologically treated water according to claim 1, further comprising means for removing a hardness component by adding a carbonate compound to the water to be treated introduced into the metal ion removing means.

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