TWI387562B - Process and treatment device for water containing biological treatment water - Google Patents

Description

Water treatment method and treatment device containing biological treatment water

The present invention relates to a method and a treatment apparatus for treating water containing biologically treated water, and more particularly to a method for treating a water containing biological treatment water containing wastewater by using a reverse osmosis (RO) membrane, thereby preventing a decrease in the permeability of the reverse osmosis membrane, and capable of long-term, A method and a treatment apparatus for treating water containing biologically treated water which are stably treated.

Recently, the requirements for environmental standards and water quality standards have become increasingly stringent, and the discharged water also needs to be highly purified. On the other hand, in order to solve the problem of insufficient water resources, it is also necessary to recover various types of discharged water and use it after high-level water treatment.

In view of the above, the reverse osmosis membrane separation treatment can effectively remove impurities such as ions, organic substances, and fine particles in water, and has been used in many fields in recent years. For example, when recycling a high-concentration TOC or a low-concentration TOC wastewater containing acetone, isopropyl alcohol, etc. discharged from a semiconductor processing step, first biologically treating the TOC component and then using a reverse osmosis membrane separation process, A method of biological treatment water purification is widely used (for example, JP-A-2002-336886).

In the past, the reverse osmosis membrane used for the reverse osmosis membrane separation treatment is usually an aromatic crosslinked polyamide composite membrane (PA membrane) or a cellulose acetate membrane (CA membrane). In addition, in the reverse osmosis membrane separation treatment, in order to prevent a decrease in the permeability (Flux), stable treatment is performed, and the water to be treated (the supply water for the reverse osmosis membrane separation treatment) supplied to the reverse osmosis membrane treatment apparatus is provided with a standard. Preferably, the pollution index (FI) specified in JIS K 3802 is 4 or less. The smaller the value of the pollution index, the smaller the load of the reverse osmosis membrane, and the less the permeability is less likely to occur.

In the conventional reverse osmosis membrane, the aromatic polyamide composite membrane has a small amount of contaminating substances such as a surfactant, a glycolipid, or a protein adsorbed in the water to be treated, and the membrane is contaminated, resulting in a rapid decrease in the permeability. The disadvantage of stable reverse osmosis membrane separation treatment cannot be continued. The cellulose acetate film has good contamination resistance compared with the aromatic polyamide composite film, but has problems such as low desalination efficiency and high operating pressure.

In recent years, although a pollution-resistant film, that is, a reverse osmosis membrane which is less likely to be contaminated by eliminating the charge on the surface of the membrane and enhancing the hydrophilicity, has been developed, it contains a polysaccharide (sugar) such as biologically treated water. When water of a highly adhesive component such as a lipid or a protein is used, the antifouling effect is low, and there is still a problem that the permeability is lowered over time.

At present, there is a device for treating sewage from manure, which is a sewage treatment device which is not easy to block the membrane pores, has a small degree of liquid permeation reduction, and can improve water quality and significantly prolong the service life of the membrane. Japanese Laid-Open Patent Publication No. 7-55318). The device does not require a process of dehydrating the faecal sewage, a process of biological nitrification and denitrification of the separated water obtained by the dehydration process, a process of coagulation treatment of the biological treatment liquid obtained by the nitrification and denitrification process, and a process of coagulation treatment. The coagulation treatment liquid is subjected to a process such as solid-liquid separation, and the membrane separation is directly carried out. Further, Japanese Laid-Open Patent Publication No. 2000-288578 discloses a method of preventing the decrease in the permeability and preventing long-term stability when the biological treatment and membrane separation using Origotrophic Bacteria is performed on water containing a trace amount of organic matter. An effective treatment method maintains the dissolved oxygen concentration in the biological reaction tank at 2 mg/L or more.

In the reverse osmosis membrane separation treatment containing biologically treated water, as a method for preventing clogging of the membrane pores, there is a method of pre-filtering and removing the dirt having high adhesion such as protein or polymer polysaccharide. However, since these adhesive substances are very small, they are not filtered by a screening program such as gravity filtration or pressure filtration, and although they are pre-filtered, they flow into the reverse osmosis membrane device, causing clogging of the membrane pores. It has recently been found that when using a precision filtration membrane device having a pore diameter of 0.45 μm or less, the obtained membrane filtration water has a pollution index of 4 or less, which satisfies the supply water requirement of the reverse osmosis membrane, but still cannot control the reverse osmosis membrane permeability. The rate is reduced.

Further, in the reverse osmosis membrane separation treatment, in order to prevent the growth of microorganisms and the decrease in the permeability due to membrane fouling in the reverse osmosis membrane device, a slurry is generally added to the supply water of the reverse osmosis membrane. However, since the price of the sizing agent is high, there is an urgent need to prevent the occurrence of microbial growth in the reverse osmosis membrane device without adding such a sizing agent.

An object of the present invention is to provide a method for preventing a decrease in the permeability of a reverse osmosis membrane when a water containing biologically treated water is treated by a reverse osmosis (RO) membrane, capable of performing treatment for a long period of time, and without requiring a reverse osmosis membrane. A method and a treatment device for treating water containing biologically treated water to which a slurry is added to the feed water.

The water treatment method containing biologically treated water of the present invention is characterized in that the treated water containing the biologically treated water is brought into contact with the chelating resin, and after the metal ions are removed, the pH is adjusted to 9.5 or more, and the reverse osmosis membrane treatment is performed. .

The water treatment method containing biologically treated water of the present invention is characterized in that the water to be treated is brought into contact with the cation exchange resin before the water to be treated is brought into contact with the conjugated resin.

The water treatment method containing biologically treated water of the present invention is characterized in that a carbonic acid compound is added to the water to be treated to remove the hardness component before the water to be treated is brought into contact with the resin.

The biological treatment water-containing water treatment device according to the present invention includes: a metal ion removing device that removes metal ions from the treated water containing the biologically treated water and the chelating resin; and the metal ion removing device The pH adjusting device of the treated water is adjusted to a pH adjusting device of 9.5 or more; and the reverse osmosis membrane separating device for treating the water obtained by the pH adjusting device is filtered.

The water treatment apparatus containing biologically treated water of the present invention is characterized by further comprising means for bringing the water to be treated introduced into the metal ion removing apparatus into contact with the cation exchange resin.

The biological treatment water-containing water treatment device of the present invention is characterized by further comprising means for adding a carbonic acid compound to the water to be treated introduced into the metal ion removal device to remove the hardness portion thereof.

According to the method and the apparatus for treating water containing biologically treated water according to the present invention, when the water containing the biologically treated water is purified by the reverse osmosis membrane separation treatment method, the permeability of the reverse osmosis membrane can be prevented from being lowered, and the water can be prevented from being long-term, The treatment is carried out steadily, and the treated water having good water quality can be obtained efficiently.

That is, as described above, pre-filtration is performed before the reverse osmosis membrane separation treatment of the reverse osmosis membrane device, and water satisfying the condition of reverse osmosis water supply, that is, water having a pollution index of 4 or less can be obtained, but permeability still occurs. Problems that decrease over time. The inventors of the present invention conducted research on this problem, and found that the cause is the multi-metal ions contained in the biological treatment water of the wastewater, and the main substance causing the pores of the membrane pores when the water containing the biological treatment water is supplied as the reverse osmosis water. Proteins, high molecular weight polysaccharides and other highly adherent dirt act as a protective clip to help the adhesion of contaminants on the surface of the membrane.

In the present invention, since the multi-metal ions are adsorbed and removed by the chelating resin before the reverse osmosis treatment, the adhesion of the contaminant on the surface of the film is suppressed, and the problem of a decrease in the permeability due to clogging of the pores of the membrane can be prevented.

That is, the chelating resin can selectively adsorb and remove the multi-metal ions, and the multi-metal ions can be effectively removed even if a 1-membered cation is present in the water to be treated. Therefore, it is possible to remove a multi-component metal ion having a high adhesive dirt such as a protein or a polymer polysaccharide which is a main substance blocked by the reverse osmosis membrane to protect the sandwich.

In particular, when a large portion of the hardness component is removed by pretreatment such as a cation exchange resin or a carbonate compound, the remaining hardness component (Ca ^{2 +} ion, Mg ^{2 +} ion, etc.) and other plural components are further removed using a chelating resin. Metal ion removal can effectively reduce the load and remove multi-metal ions.

Further, in the present invention, since the pH of the metal ion-removed water is adjusted to 9.5 or more and supplied to the reverse osmosis membrane, the following effects can be obtained.

(1) Since microorganisms cannot survive in an alkaline environment, the water supplied to the reverse osmosis membrane is adjusted to pH 9.5 or higher, and an environment in which microorganisms cannot survive without a nutrient source can be created. Furthermore, there is no need to add an expensive pasting agent of the past.

(2) A highly adherent stain such as a protein or a polymer polysaccharide which is a main substance blocked by the reverse osmosis membrane, and it is not known that it is less likely to adhere to the membrane surface at a pH of 9.5 or more. Therefore, by adjusting the reverse osmosis membrane supply water to an alkalinity of pH 9.5 or more, it is possible to further effectively suppress the clogging of the membrane surface.

Further, in such a strongly alkaline environment, when the reverse osmosis membrane is supplied with a very small amount of multi-metal ions in the water, if calcium ions are contained, calcium rust such as calcium carbonate or calcium phosphate may be precipitated on the surface of the reverse osmosis membrane. However, in the present invention, the multi-metal ions in the raw water are previously removed to a very low concentration by the chelating resin, so that precipitation of rust in the above-mentioned strongly alkaline environment can be suppressed.

In the present invention, before the metal ion is removed by the chelating resin, the cation exchange resin treatment can reduce the load of the conjugated resin, improve the efficiency of adsorbing the multi-metal ion by the chelating resin, and reduce the frequency of regeneration and long-term stability. deal with.

That is, if the biologically treated water is directly treated with the chelating resin, the chelating resin quickly loses its adsorption capacity and needs to be regenerated frequently. Therefore, before the use of the chelating resin, the hardness component is almost removed in advance by the cation exchange resin treatment method, whereby the efficiency of the adsorption of the multi-metal ion by the conjugated resin can be improved, and the frequency of regeneration can be reduced.

In the present invention, before the metal ion is removed by the chelating resin, the carbonic acid compound is added, and the hardness component is almost completely removed in advance, the load of the conjugated resin can be reduced, and the efficiency of adsorbing the multi-metal ion by the chelating resin can be improved and reduced. Its reproduction frequency.

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

Water containing biologically treated water suitable for use in the present invention includes electronic equipment industries such as semiconductors or liquid crystals, machinery manufacturing industries such as automobiles and home appliances, industrial materials manufacturing industries such as steel, cement, resins or films, and foods such as cold drinks, wine, and dairy products. Wastewater discharged from the processing industry, such as standard sludge method, anaerobic aerobic method, loop-type nitrification and denitrification method, oxidation tank, fractional activated sludge method, plankton method, microbial fixation method, scattered water bed Method, rotary disk method, contact oxidation method, biological filtration method, biological deodorization method, etc., aerobic treatment such as aerobic treatment, or anaerobic treatment, anaerobic treatment, or the like Water discharge water, etc.

The present invention is particularly applicable to biologically treated water containing organic carbon (TOC) discharged from a semiconductor production process or water containing biologically treated water such as integrated drainage (including domestic drainage) into which the biologically treated water flows.

The water content of the biologically treated water to be used in the present invention is not particularly limited, and preferably the TOC concentration is 0.5 to 20 mg/L, and the concentration of the multicomponent metal ion contained in the water containing the biologically treated water is preferably 10 to 1000 mg/ L is more preferably 20 mg or more and 500 mg or less, and 100 mg or more is most preferable.

Further, the multi-metal ion concentration represents a total of calcium ions, magnesium ions, aluminum ions (dissolved aluminum), and iron ions (dissolved iron).

The water containing biologically treated water suitable for use in the present invention preferably contains a large amount of multi-metal ions to contribute to organic contamination of the reverse osmosis membrane, for example, an agglomeration treatment containing an inorganic coagulant such as calcium sulphate, PAC or iron HCl. Inorganic wastewater. The water containing biologically treated water treated by the present invention preferably has a calcium ion concentration of 50 mg/L or more, and most preferably 100 to 500 mg/L. The present invention is very useful for such water containing biologically treated water with calcium ions. effective.

For such water containing biologically treated water, the present invention is first contacted with a chelating resin to remove metal ions, especially multi-metal ions, prior to the reverse osmosis membrane treatment.

The chelating resin used herein may be any chelating resin for removing metal ions, and any resin may be used, for example, a conjugated resin obtained by combining a crosslinked styrene substrate with imino (di)acetic acid.

The method of contacting the conjugated resin with the water to be treated is not particularly limited, and the treated water is passed through a ruthenium resin column filled with a ruthenium resin, or passed through a cation exchange in the column as shown in Fig. 1 to be described later. The resin layer and the ion exchange column of the kneading resin layer may be used. At this time, the water passage mode of the kneading resin column or the ion exchange column may be either a downward flow or an upward flow. Further, there is no particular limitation on the type of the tower such as a fixed bed or a fluidized bed. The water-passing SV is preferably 5 to 50 hr-1, more preferably 10 to 30 hr-1.

After the metal ions contained in the biological treatment water are adsorbed and removed by using a chelating resin, hydrazine or the like is added to adjust the pH to 9.5 or more, preferably to pH 10 to 11, and then subjected to reverse osmosis membrane treatment. Here, if the pH of the reverse osmosis membrane supply water is less than 9.5, the effects of the above (1) and (2) are not obtained. When the pH is too high, a large amount of hydrazine is required, and a large amount of acid is required at the pH adjustment after the reverse osmosis membrane separation treatment. Therefore, the above range is preferred.

The reverse osmosis membrane used for the reverse osmosis membrane separation treatment may be an alkali-resistant membrane such as a polyetheramide composite membrane, a polyvinyl alcohol composite membrane, or an aromatic polyamide composite membrane. There are no special restrictions. In the present invention, the aromatic crosslinked polyamide composite film is particularly effective in the case where the film is easily contaminated by a microadhesive substance such as a surfactant, a glycolipid or a protein.

The reverse osmosis membrane separation treatment is not limited to one layer treatment using one reverse osmosis membrane device. Two or more reverse osmosis membrane separation apparatuses may be arranged in a plurality of layers in series, and subjected to a high-pressure treatment by a multi-layer reverse osmosis membrane separation treatment.

In the present invention, as described above, it is preferable to remove the metal ions using a chelating resin before the reverse osmosis membrane separation treatment, so that the supply water of the reverse osmosis membrane separation device contains a polyhydric metal ion concentration of 10 μg/L or less. When the concentration of the multi-metal ions is higher than this range, there is a possibility that rust is formed on the reverse osmosis membrane.

Further, when the water recovery rate of the reverse osmosis membrane device is increased, the multi-metal ions and the organic binder are concentrated, and it is easy to cause the combination of the two and the adhesion to the membrane. Therefore, the water recovery rate of the reverse osmosis membrane separation device is preferably 80% by weight or less, for example, 60 to 80% by weight.

For the present invention, the metal ion can also be removed by using a cation exchange resin before the metal ion is removed using the chelating resin. As the cation exchange resin, a Na-type strong cation exchange resin or a weak cation exchange resin is preferably used.

After treatment with a Na-type strong cation exchange resin, treatment with a chelating agent has the following advantages.

That is, if an H-type strong cation exchange resin is used, the treated water is acidic, and when the pH of the reverse osmosis membrane feed water is subsequently adjusted to 9.5 or more, it is necessary to add more hydrazine. Further, in water containing biologically treated water, a large amount of sodium ions are often contained. Therefore, when a strong cation exchange resin of type H is used, a hardness component such as calcium or magnesium which is a main substance of rust is generated due to sodium ions. The amount of adsorption is lowered, and the regeneration process has to be performed frequently. When a Na-type strong cation exchange resin is used, the pH of the treated water is neutral and there is no problem that the amount of adsorption of the hardness component caused by the sodium ions is lowered.

Although a cation exchange resin is used for the treatment, a hardness component of several hundred μg/L to several mg is generally leaked. Therefore, after treatment with a Na-type strong cation exchange resin, in order to remove the hardness of the multi-metal ion, water is passed through the chelating resin having a good property of selectively adsorbing the multi-metal ion, thereby allowing the biological treatment water to be contained. It is possible to reduce the amount of multi-metal ions contained in water to an infinitely low level.

It can also be treated with a H-type strong cation exchange resin and then treated with a chelating resin. However, since the chelating resin is liable to cause a decrease in the ability to adsorb hardness components in an acidic environment, the use of a Na-type strong cation exchange resin is relatively In the case, the frequency of reproduction will become high.

Further, after treatment with a weak cation exchange resin, treatment with a chelating agent has the following advantages.

The weak cation exchange resin is the same as the Na type strong cation exchange resin, and the pH of the treated water is neutral. However, when the water is treated, the concentration of the leaked hardness component in the reverse osmosis membrane device cannot fully suppress the occurrence of rust. . Here, by treating with a weak cation exchange resin and then treating with a chelating resin, the polyvalent metal ions contained in the water containing the biologically treated water can be reduced to an extremely low level.

Further, a method of supplying water to the resin may be a method of passing water through a packed column filled with a Na-type strong cation exchange resin or a weak cation exchange resin, and then passing through a packed column filled with a bismuth resin; or A method in which a water collecting plate is provided in a charging tower and a filling tower of two kinds of resins is filled with water. The water passing SV of the filling tower is preferably 5 to 50 hr-1, more preferably 10 to 30 hr-1, and the water passing method may be downward flow, upward flow, fixed bed, fluidized bed, or the like, without particular limitation.

The resin regeneration method in this case is as follows.

In the method of using water to pass through a Na-type strong cation exchange resin and then passing water to the chelating resin, there is a method of sequentially regenerating or individually regenerating in a sequence of a sulphuric acid resin or a Na-type strong cation exchange resin using a NaCl aqueous solution; The order of the resin and the Na-type strong cation exchange resin is followed by the formation of the H-type by acid, and then conversion to the Na-type by using NaCl or NaOH; or the regeneration of the ruthenium resin by the acid, The order of the Na type strong cation exchange resin is a method of converting to a Na type by using NaCl or NaOH.

In the method of using water to the weak cation exchange resin and then passing the water to the chelating resin, in the order of the hydrazine resin and the weak cation exchange resin, after the H form is sequentially formed by the acid, only the chelating resin is used for NaCl. Or a method in which NaOH is converted into a Na type; or a method in which a weak cation exchange resin is used as an acid, and a chelating resin is separately regenerated by using NaCl or NaOH.

The regeneration method includes cocurrent regeneration and countercurrent regeneration, but it is preferable to use countercurrent regeneration because of high regeneration efficiency.

Further, in the present invention, a carbonic acid compound may be added to water containing biologically treated water to remove the hardness component before the metal ion is removed by the chelating resin. That is, a carbonic acid compound is added to water containing biologically treated water, and a hardness component such as calcium is precipitated as a carbonate, and then separated.

In the above case, a carbonate such as sodium carbonate or sodium hydrogencarbonate is added to water containing biologically treated water or carbonated gas is poured thereinto to precipitate a metal carbonate such as calcium carbonate. The precipitated metal carbonate is removed by a filtration device such as sand filtration, precision filtration, ultrafiltration, nanofiltration or the like. It is also possible to combine two or more of the above filtration devices for filtration. The TOC component contained in the water containing the biologically treated water can be removed by the above-described carbonate precipitation and filtration removal. Further, the amount of the carbonic acid compound to be added is preferably 1 to 3 times the equivalent of the metal ion, and when the multicomponent metal ion of the chelating agent or the dispersing agent is mixed, it is necessary to increase the amount of addition. After filtering the carbonate, it is possible to carry out a pH adjustment (pH 5 to 6.5) and/or a treatment for removing residual carbonic acid components by gas explosion or the like as necessary.

By the above treatment, the metal ions contained in the water containing the biologically treated water can be precipitated as carbonate, and the precipitates can be removed. However, in general, the concentration of the multi-metal ion of the treated water is still high in the range of several mg/L to several tens of mg/L, and in order to completely control the problem of the formation of rust in the reverse osmosis membrane, it is necessary to carry out the treatment of the resin.

In the present invention, before the step of removing metal ions, pretreatment of removing suspended matter in raw water by pressure filtration, gravity filtration, precision filtration, ultrafiltration, pressurized floating, precipitation, or the like may be performed. Thereby, the rise in the differential pressure of the resin-filled tower can be controlled. In addition, an activated carbon column can be disposed to adsorb and remove organic matter, and reduce the TOC concentration of water flowing into the kneading resin filling tower and the reverse osmosis membrane separation device.

Fig. 1 is one of the embodiments of the water treatment apparatus containing biologically treated water of the present invention. As shown in Fig. 1, the water containing the biologically treated water is sent to the ion exchange column 1, and the cation exchange resin 1A and the chelating resin 1B are sequentially treated in the ion exchange column 1 to remove the water containing the biologically treated water. Contains metal ions. After the treated water of the ion exchange column 1 passes through the tank 2, hydrazine or the like is added thereto to adjust the pH to 9.5 or more, and the pump P is introduced into the reverse osmosis membrane separation device 3 to carry out reverse osmosis membrane treatment. The permeated water that has passed through the reverse osmosis membrane separation device 3 is extracted as the final treated water. If concentrated water is required, it may be subjected to evaporation concentration treatment or activated carbon treatment according to its water quality, and then discharged into a river or a sewer.

1 is one of the embodiments of the present invention, and the present invention is not limited to any of the drawings without departing from the scope of the invention. That is, as described above, a pretreatment apparatus such as a filtration device or activated carbon can be provided before the ion exchange column. Further, the reverse osmosis membrane device may be a multilayer of two or more layers. Further, instead of the hardness component, a chromatographic resin column may be used instead of the ion exchange column filled with the cation exchange resin and the chelating resin, and a carbonic acid added to the water containing the biological treatment water may be provided in the front stage of the conjugated resin column. A stirring tank for separating metal carbonate by salt or carbonic acid gas; and a filtering device for filtering water flowing out of the stirring tank.

The invention will now be described more specifically by way of examples and comparative examples. However, the present invention is not limited to the following embodiments within the scope of not exceeding the scope of the invention.

Example 1

The organic waste water discharged from the semiconductor factory and biologically treated by the biological filtration device and the integrated drainage containing the hydrofluoric acid drainage combined with the agglutination treatment are used as the water containing the biological treatment water, and the same is shown in FIG. The device is processed. The integrated drainage has a TOC concentration of 5 mg/L, a total hardness of 300 mg/Las CaCO3, a Na+ concentration of 200 mg/L, and a multicomponent metal ion concentration of 320 mg/L. In the order of the Na-type strong cation exchange resin ("SKIB" manufactured by Mitsubishi Chemical Corporation) and the layer of imide (di)acetic acid-based resin ("CR11" manufactured by Mitsubishi Chemical Corporation), SV30 hr-1 water.

The water quality of the obtained treated water is shown in Table 1. After adding NaOH to the treated water to adjust the pH to 10.5, a reverse osmosis membrane separation apparatus ("ES-20" manufactured by Nitto Denko Corporation) was used, and the operating pressure was 0.75 MPa and the water recovery rate was 80%. The reverse osmosis membrane separation process was carried out.

The result of observing the time change of the permeability of the reverse osmosis membrane separation device at this time is shown in Fig. 2 . Moreover, the water quality of the reverse osmosis membrane permeating water and concentrated water is shown in Table 1.

Comparative example 1

The reverse osmosis membrane separation treatment was carried out under the same conditions as in Example 1 except that the pH of the reverse osmosis membrane feed water was 7, and a 3 mg/L slurry ("EC-503" manufactured by Kurida Co., Ltd.) was added. The result of investigation of the change in the permeability of the reverse osmosis membrane separation apparatus in this case was as shown in Fig. 2 .

Comparative example 2

The reverse osmosis membrane separation treatment was carried out under the same conditions as in Example 1 except that the treatment of the bismuth resin was not carried out, and the time change of the permeability of the reverse osmosis membrane separation device in this case was investigated as shown in Fig. 2 . Shown.

Comparative example 3

To the above-mentioned integrated water, 3 mg/L of a sizing agent ("EC-503" manufactured by Kurida Co., Ltd.) and a hexa-phosphate rust dispersing agent (10 mils of Pritar Chemical Co., Ltd.) L401"), after adjusting the pH to 7, the water was supplied as a reverse osmosis membrane, and the reverse osmosis membrane treatment was performed under the same conditions as in Example 1. The results of investigation of the temporal change in the permeability of the reverse osmosis membrane separation device at this time are shown in Fig. 2 .

As can be seen from Fig. 2, in Example 1, after the removal of the metal ions, the reverse osmosis membrane treatment was carried out under high pH conditions, and the permeability decreased slowly with respect to Comparative Examples 1 to 3, and the water flow started for 60 hours. After that, 0.2 to 0.4 m ³ /m ² appeared compared with Comparative Examples 1 to 3. The degree of permeability of d is poor.

Further, in the surface of the reverse osmosis membrane after the water was passed, in Comparative Example 1, the gelatinous organic matter and the calcium carbonate rust were adhered, in Comparative Example 2, the calcium carbonate rust was adhered, and in Comparative Example 3, the gel was adhered. Organic matter. On the other hand, in Example 1, almost no adhesive was observed on the surface of the reverse osmosis membrane.

1. . . Ion exchange tower

1A. . . Cation exchange resin

1B. . . Compound resin

2. . . tank

3. . . Reverse osmosis membrane separation device

Fig. 1 is a system diagram showing an embodiment of a water treatment apparatus containing biologically treated water according to the present invention.

Fig. 2 is a graph showing the temporal change of the permeability of the reverse osmosis membrane separation apparatus of Example 1 and Comparative Examples 1 to 3.

1‧‧‧Ion Exchange Tower

1A‧‧‧cation exchange resin

1B‧‧‧Combined resin

2‧‧‧cans

3‧‧‧Reverse osmosis membrane separation device

Claims (4)

A method for treating water containing biologically treated water, wherein the treated water containing the biologically treated water is brought into contact with the chelating resin, and after removing the metal ions, the pH is adjusted to 9.5 or more, and the reverse osmosis membrane is treated. Before contacting the treated water with the conjugated resin, the treated water is brought into contact with the Na-type strong cation exchange resin to remove the hardness component, and the residual hardness component and the other multi-metal ion are further passed through the chelating resin. Remove. A method for treating water containing biologically treated water, wherein the treated water containing the biologically treated water is brought into contact with the chelating resin, and after removing the metal ions, the pH is adjusted to 9.5 or more, and the reverse osmosis membrane is treated. Before the treated water is brought into contact with the conjugated resin, a carbonic acid compound is added to the water to be treated to remove the hardness component, and the residual hardness component and the other multi-metal ions are removed by the chelating resin. A water treatment device containing biologically treated water, comprising: a metal ion removing device for contacting a treated water containing biologically treated water with a chelating resin to remove metal ions; and a pH of the treated water obtained from the metal ion removing device a pH adjusting device whose value is adjusted to 9.5 or more; a reverse osmosis membrane separating device for filtering treated water obtained from the pH adjusting device, characterized in that it comprises a treated water and Na introduced into the metal ion removing device The apparatus for contacting the strong cation exchange resin to remove the hardness component removes the residual hardness component and other multi-metal ions by the metal ion removing device. A water treatment device containing biologically treated water, comprising: a metal ion removing device for contacting a treated water containing biologically treated water with a chelating resin to remove metal ions; and a pH of the treated water obtained from the metal ion removing device a pH adjusting device whose value is adjusted to 9.5 or more; a reverse osmosis membrane separating device for filtering treated water obtained from the pH adjusting device, characterized in that it comprises adding carbonic acid to the water to be treated introduced into the metal ion removing device The compound, which removes the hardness portion thereof, removes the residual hardness component and other multi-metal ions by the metal ion removing device.