JP2008238051A - Organic matter treatment method and organic matter treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain treated water of high quality by efficiently reducing the concentration of TOC in water simultaneously with performing long-term stable treatment by suppressing bio-fouling caused in a recovery system and preventing the lowering of the flux of an RO membrane by reducing organic matter using an RO membrane separator after the hardness component of organic matter-containing wastewater containing a large amount of the hardness component discharged from an electronic device manufacturing factory and other various fields is reduced without using an ion exchange resin column. <P>SOLUTION: After a sterilant is added to organic matter-containing water, the organic matter-containing water is passed through a first RO membrane separator 2 having a hardness component removing function and oxidation resistance and, after alkali is added to first RO treated water to adjust the pH thereof to 9.5 or above, tile left sterilant is removed by an activated carbon column 4 and the first RO treated water is subsequently passed through a second RO membrane separator 5 to be treated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an organic matter treatment method and an organic matter treatment apparatus that remove organic matter in water by passing organic substance-containing water through a reverse osmosis membrane (RO membrane) separator. Specifically, when wastewater containing high-concentration TOC or low-concentration TOC discharged from an electronic device manufacturing factory or the like is treated with an RO membrane separation device to collect treated water, biofouling in the collection system and RO membrane Treatment of wastewater containing organic matter that prevents permeation flux (flux) reduction due to blockage of organic matter and performs stable treatment over a long period of time, and at the same time efficiently reduces the TOC concentration in water to obtain high-quality treated water The present invention relates to a method and a processing apparatus.

  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, for the purpose of eliminating water shortage, advanced water treatment is desired in order to collect and reuse various wastewater.

  Under such circumstances, RO membrane separation treatment has been used in many fields in recent years because it can effectively remove impurities (ions, organic substances, fine particles, etc.) in water. I came. For example, when organic wastewater containing acetone, isopropyl alcohol, etc. discharged from the semiconductor manufacturing process is collected and reused, it is first biologically treated to sufficiently remove the TOC component and then purified by RO membrane treatment. A method is widely adopted (for example, JP-A-2002-336886).

  However, in recent years, when biological treatment wastewater is passed through an RO membrane separation device, there is a problem that the membrane surface of the RO membrane separation device is blocked by the biological metabolite produced by the decomposition of organic matter of microorganisms and the flux is reduced. It has begun to become.

On the other hand, when organic wastewater is directly passed through the RO membrane separator without performing biological treatment, the TOC concentration flowing into the RO membrane separator is high. Become.
Therefore, in order to suppress biofouling in the RO membrane separation device, a large amount of slime control agent is usually added, but since the slime control agent is expensive, cheaper biofouling is performed. There is a need for a ring suppression method.
In addition, non-ionic surfactants that may adhere to the membrane surface of the RO membrane separation device and reduce the flux may be mixed in the wastewater from the electronic device manufacturing factory. RO membrane treatment could not be applied to agent-containing wastewater.

  In order to improve the problems that occur when RO membrane treatment is performed on organic matter-containing water such as biological treatment wastewater, a scale dispersant is added to the organic matter-containing water at least 5 times the raw water calcium concentration, and the pH is 9. A system that reduces the decrease in the flux of the RO membrane by adjusting the RO membrane to 5 or more and enables stable supply of treated water has been proposed (Japanese Patent Laid-Open No. 2006-181397).

  In this system, when a large amount of hardness components are present in the raw water (for example, 10 mg / L or more in total hardness), an ion exchange resin tower (for example, a cation exchange resin tower) is used as a hardness removing means in the previous stage of the RO membrane separator. However, in this case, since organic substances are present in the raw water of the system, slime tends to propagate in the ion exchange resin tower. In addition, there is a problem that the RO security filter or the RO membrane installed in the subsequent stage is blocked by the biofilm peeled from the tower. Therefore, sterilization treatment is required in the front stage of the ion exchange resin tower, but if a bactericidal agent is added in the front stage of the ion exchange resin tower, the ion exchange resin may cause resin deterioration due to the bactericidal agent. Cannot be added.

For this reason, in the above system, it is difficult to remove the hardness component in the raw water at the front stage of the RO membrane separator.
JP 2002-336886 A JP 2006-181397 A

  The present invention solves such a conventional problem, for example, an organic substance-containing wastewater containing a large amount of hardness components (for example, 10 to 20 mg / L in total hardness) discharged from an electronic device manufacturing factory and other various fields. After reducing the hardness component without using an ion exchange resin tower, organic substances are reduced by using an RO membrane separator, thereby suppressing slime reproduction (biofouling) that occurs in the recovery system system, and the RO membrane An object of the present invention is to provide a method and an apparatus for preventing a decrease in flux and performing a stable treatment over a long period of time, and at the same time, efficiently reducing the TOC concentration in water to obtain a high-quality treated water.

  As a result of earnestly examining the method for removing the hardness component in the organic substance-containing water, the present invention adds a bactericide to the organic substance-containing water and then treats it with an oxidation-resistant RO membrane having a hardness component removing function. This treatment water is made alkaline with a pH of 9.5 or more, and the remaining bactericides are removed and then treated with the RO membrane. It was found that it can be removed, and the present invention was completed.

  That is, the organic matter treatment method of the present invention includes a disinfectant addition step of adding a disinfectant to the organic matter-containing water in the organic matter treatment method of removing the organic matter in the water by passing the organic matter-containing water through the RO membrane separator. The first RO membrane treatment step for passing the treated water that has undergone the disinfectant addition step through the first RO membrane separation device having a hardness component removal function and oxidation resistance, and the first RO membrane treatment step An alkali addition step of adding alkali to the treated water that has undergone the treatment to bring the pH to 9.5 or higher, a bactericide removal step that removes the bactericide remaining in the treated water that has undergone the alkali addition step, and the bactericide removal step And a second RO membrane treatment step of treating the treated water with the RO membrane.

  The organic matter treatment apparatus of the present invention is an organic matter treatment apparatus that removes organic matter in the water by passing the organic matter-containing water through the RO membrane separation device, and a disinfectant addition means for adding a disinfectant to the organic matter-containing water. The first RO membrane separation device having a hardness component removal function and oxidation resistance through which the treated water of the disinfectant adding means is passed, and alkali is added to the treated water of the first RO membrane separation device The alkali addition means for setting the pH to 9.5 or higher, the bactericidal agent removal means for removing the bactericidal agent remaining in the treated water of the alkali addition means, and the treated water of the bactericidal agent removal means are passed through And an RO membrane separation apparatus.

In the present invention, a bactericide is added to organic substance-containing water (raw water), and first, the hardness component in the raw water is removed with an oxidizing first RO membrane having a hardness component removing function. Generally, RO membranes that exhibit oxidation resistance, such as cellulose acetate membranes, have high removability to scale factor substances such as calcium and magnesium, but RO membranes that do not exhibit oxidation resistance, such as organic matter removal rate. Extremely low compared to polyamide RO membrane. Therefore, in the present invention, although the hardness component in the raw water is eliminated by the first RO membrane, the treated water of the first RO membrane (permeated water, hereinafter referred to as “first RO treated water”). ) Contains a large amount of organic matter, which may cause slime contamination in the subsequent apparatus. Therefore, in the present invention, an alkaline agent such as sodium hydroxide is added to the first RO treated water to adjust the pH to 9.5 or higher. The reason why the pH is adjusted to 9.5 or higher is as follows.
That is, microorganisms cannot live in the alkaline region. Therefore, by adjusting the pH to 9.5 or more, it is possible to create an environment in which nutrient sources such as N, P, trace metals, organic matter, etc. exist in water but microorganisms cannot live. For this reason, biofouling is prevented in a subsequent apparatus such as the second RO membrane through which water having a pH of 9.5 or higher is passed.
In addition, it is known that nonionic surfactants that may reduce the flux of the RO membrane are desorbed from the membrane surface in the alkaline region. By increasing the pH to 9.5 or more, the membrane surface of these components It becomes possible to suppress adhesion to the surface.

  In addition, since the disinfectant remaining in the first RO treated water is removed before the second RO membrane, deterioration of the RO membrane due to the disinfectant is prevented.

  According to the present invention, an ion exchange resin tower is used for drainage containing organic matter containing a large amount of hardness components, for example, about 10 to 20 mg / L in total hardness, discharged from an electronic device manufacturing factory and other various fields. After reducing the amount of hardness component without reducing the organic matter using the RO membrane separator, it prevents the slime breeding (biofouling) that occurs in the recovery system system, and prevents the RO membrane flux from decreasing. At the same time as performing a stable treatment over a long period, high-quality treated water can be obtained by efficiently reducing the TOC concentration in water (claims 1 and 6).

  In the present invention, the pH condition in the first RO membrane treatment suppresses degradation due to hydrolysis of the RO membrane and suppresses scale formation on the membrane surface, and also removes cations as shown in FIG. 2 described later. From the viewpoint of properties, pH 4 to 6, particularly about pH 4.5 to 5 is preferable. Therefore, prior to the first RO membrane treatment, it is preferable to adjust the pH to 4 to 6 by adding a pH adjuster to the raw water (claims 2 and 7).

  In addition, it is preferable to remove suspended substances in the raw water after adding the bactericide to the raw water (claims 3 and 8).

  In addition, the first RO membrane used in the present invention is not particularly limited as long as it has antibacterial resistance, but it is long-term operation to use a cellulose acetate membrane excellent in oxidation resistance and contamination resistance. It is preferable from the viewpoint of stability (claims 4 and 9).

Moreover, in this invention, it is preferable to add the scale inhibitor 5 weight times or more of the calcium ion in water to 1st RO treated water, and to let water flow to a 2nd RO membrane. .
That is, when the hardness component concentration in the raw water is high (for example, when the total hardness is 20 mg / L or more), the hardness component removal by the first RO membrane becomes insufficient, and the hardness component (especially calcium) in the first RO treated water. May remain. If the hardness component concentration in the first RO treated water that is passed through the second RO membrane is 5 mg / L or more in total hardness, scale failure may occur in the latter stage. In such a case, the scale dispersant Is preferably added.
Here, the reason for adding a scale inhibitor at least 5 times the weight of calcium ions in water to be passed through the second RO membrane is as follows.
That is, in the present invention, since the alkali is added to the first RO treated water so as to have a pH of 9.5 or higher, the pH of the water passed through the second RO membrane is 9.5 or higher. Under the RO operating condition of pH, even if a very small amount of calcium ions is mixed, a scale such as calcium carbonate is generated and the RO membrane is immediately blocked. Accordingly, a scale inhibitor is added for the purpose of suppressing the clogging of the membrane surface due to such scale. However, if the added amount of the scale inhibitor is less than 5 times the calcium ion concentration, the addition effect is not sufficient. More than 5 times the ion concentration.

Embodiments of an organic matter processing method and an organic matter processing apparatus according to the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a system diagram showing an embodiment of an organic matter processing method and an organic matter processing apparatus of the present invention.

  In FIG. 1, after adding a bactericidal agent and a pH adjuster to organic substance-containing water (raw water) in the raw water tank 1, the water is passed through the first RO membrane separator 2.

Here, as bactericides to be added to raw water, chlorine-based bactericides such as hypochlorous acid (HClO), sodium hypochlorite (NaClO), potassium hypochlorite (KClO), chlorine dioxide (ClO ₂ ), etc. Can be suitably used.
These bactericides may be used alone or in combination of two or more.
The amount of the bactericide added depends on the quality of the raw water, but usually the concentration of free chlorine remaining in the treated water of the first RO membrane separation device 2 in the subsequent stage is about 0.3 to 1 mg-Cl ₂ / L. It is preferable to add.

  Further, as shown in an experimental example to be described later, the hardness component removal rate in the first RO membrane separation device 2 may be referred to as water that is passed through the first RO membrane separation device 2 (hereinafter referred to as “first RO water supply”). ) Is 4 to 6, particularly about 4.5 to 5, good results can be obtained. To the raw water, if necessary, a pH adjusting agent such as acid or alkali is added, Adjust to pH 4-6, preferably pH 4.5-5.

  Note that either the bactericide or the pH adjuster may be added first, or both may be added simultaneously to the raw water.

  In FIG. 1, the concentrated water of the second RO membrane separation device 5 at the subsequent stage is returned to the raw water tank 1 and circulated. Thus, the water recovery rate can be increased by circulating the concentrated water of the second RO membrane separation device 5 having relatively good water quality.

  The water to which the pH adjusting agent and the bactericidal agent are added in the raw water tank 1 is subjected to RO membrane treatment in the first RO membrane separation device 2, the concentrated water is discharged out of the system, and the permeated water (first RO treated water) is treated water. It is fed to the tank 3.

  In the present invention, as the RO membrane of the first RO membrane separation device 2, an oxidation resistant membrane having a hardness component removing function is used. Although there is no restriction | limiting in particular as this RO membrane, It is preferable to use a cellulose acetate membrane from being excellent in oxidation resistance and contamination resistance.

  In the first RO membrane separation device 2, the hardness components (calcium and magnesium) in the raw water are removed by the RO membrane having the hardness component removal function.

The first RO treated water is adjusted to pH 9.5 or higher by adding an alkali such as sodium hydroxide or potassium hydroxide, and then sequentially passed through the treated water tank 3 to the activated carbon tower 4 and the second RO membrane separator 5. Watered.
Here, when the pH of water (hereinafter sometimes referred to as “second RO feed water”) passed through the activated carbon tower 4 and the second RO membrane separation device 5 is lower than 9.5, the activated carbon tower 4 and the second RO Biofouling in the membrane separator 5 or the like cannot be prevented. Therefore, the first RO treated water is adjusted to pH 9.5 or more, preferably pH 10.5 to 11 by addition of alkali.

In the activated carbon tower 4, the disinfectant remaining in the first RO treated water is decomposed and removed.
In the present invention, the disinfectant removing means is not particularly limited as long as it can remove the disinfectant, and the addition of a reducing agent such as sodium hydrogen sulfite (NaHSO ₃ ) or the use of activated carbon, activated carbon filter or the like. it can.

The activated carbon used in the activated carbon tower 4 is not particularly limited as long as it can remove the bactericide such as coal-based or coconut shell-based. Further, the water flow method may be either an upward flow or a downward flow, and the water flow SV is not particularly limited, but is preferably ¹ to 40 hr ⁻¹ .

The water from which the residual disinfectant has been removed by the activated carbon tower 4 is passed through the second RO membrane separation device 5 under the condition of pH 9.5 or higher, whereby the TOC is removed.
The RO membrane of the second RO membrane separation device 5 is not particularly limited as long as it has excellent alkali resistance, such as a polyetheramide composite membrane, a polyvinyl alcohol composite membrane, and an aromatic polyamide membrane.

  The concentrated water of the second RO membrane separation device 5 is circulated to the raw water tank 1, and the permeated water (hereinafter sometimes referred to as "second RO treated water") is usually adjusted to pH 4-8 by adding an acid, If necessary, the product is further treated with activated carbon and then reused or discharged. There is no restriction | limiting in particular as an acid used here, Mineral acids, such as hydrochloric acid and a sulfuric acid, are mentioned.

  As shown in FIG. 1, a bactericide is added to raw water and the pH is adjusted to 4 to 6 and treated with the first RO membrane separation device 2, and then adjusted to pH 9.5 or higher, and then activated carbon treatment and RO membrane separation are performed. By processing, without causing a decrease in the flux in the second RO membrane separation device 5, and preventing biofouling of the activated carbon tower 4 and the RO membrane separation device 5, performing a stable treatment over a long period of time, High quality treated water from which TOC has been removed can be obtained.

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.
For example, when the concentration of suspended solids in the raw water is high, it is preferable to remove the suspended solids in the raw water by adding a bactericide to the raw water and then performing a coagulation filtration treatment or the like. In this case, the coagulation filtration means is not particularly limited as long as it can remove suspended substances contained in the raw water, such as pressure filtration, gravity filtration, microfiltration, ultrafiltration, pressurized flotation, and precipitation.

  Moreover, after adding a scale inhibitor to the first RO treated water, it may be passed through the second RO membrane separation device 5. In this case, the scale inhibitor used is likely to dissociate in the alkaline region and form a complex. Chelate scale inhibitors such as ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) are preferably used, but other (meth) acrylic acid polymers and salts thereof, maleic acid polymers and salts thereof, etc. Molecular weight polymers, ethylenediaminetetramethylenephosphonic acid and its salts, hydroxyethylidene diphosphonic acid and its salts, nitrilotrimethylenephosphonic acid and its salts, phosphonobutanetricarboxylic acid and its salts, phosphonic acids and phosphonates, hexametaphosphoric acid and its Inorganic polymerized phosphoric acid and inorganic weight such as salt, tripolyphosphoric acid and its salt It can be used as phosphates. These may be used alone or in combination of two or more.

  Further, the addition position of the scale inhibitor is not particularly limited as long as it is the latter stage of the first RO membrane separation device 2, but when activated carbon is used as the disinfectant removing means, the scale inhibitor is adsorbed on the activated carbon, and the second RO membrane. Since the scale dispersion effect in the separation device 5 may be reduced, it is preferable to add a scale inhibitor after the disinfectant removing means.

  When a scale inhibitor is added to the first RO-treated water, the amount of the scale inhibitor added is preferably 5 times or more, particularly 5 to 50 times the weight of calcium ions in water. If the addition amount of the scale inhibitor is too small, a sufficient addition effect cannot be obtained, and an effect commensurate with an excessive chemical cost cannot be expected.

  Such an organic matter treatment method and an organic matter treatment apparatus according to the present invention include water containing a large amount of hardness components, for example, the hardness component concentration is 10 to 20 mg / L in total hardness, and since it contains organic matter, It is suitable for the treatment of general waste water and the like where fouling is likely to occur.

  Hereinafter, the present invention will be described in more detail with reference to experimental examples, examples and comparative examples.

<Experimental example 1>
In the present invention, in order to investigate the preferred pH condition of the cellulose acetate membrane suitably used as the first RO membrane, hydrochloric acid (HCl) is added to the coagulation filtration treated water obtained in the same manner as in Example 1 described later. ) Or sodium hydroxide (NaOH) and adjusted to a different pH in the range of pH 4-8, and in the same manner as in Example 1, the RO membrane separator loaded with the cellulose acetate membrane was 80 L / hr, recovered. The removal rate of magnesium (Mg) and sodium (Na) when water was passed at a rate of 75% was examined, and the relationship with pH is shown in FIG.
From FIG. 2, it can be seen that in the RO membrane treatment with the cellulose acetate membrane, an excellent hardness component removal rate can be achieved by operating at a feed water pH of 4 to 6, particularly pH of 4.5 to 5. Here, only the magnesium removal rate is taken as an example, but the hardness removal rate in the first RO membrane is the same for both magnesium and calcium.

<Example 1>
After adding sodium hypochlorite (NaClO) as a free chlorine to 0.5 mg-Cl ₂ / L to waste water with a TOC concentration of 10 mg / L and a calcium concentration of 5 mg / L, an addition amount of polyaluminum chloride (PAC) Aggregation filtration treatment was performed by passing water through a filter under the conditions of 20 mg / L and pH 6.5. After adjusting the pH to 5 by adding hydrochloric acid (HCl) to this coagulated filtration treated water, water was passed through the first RO membrane separator loaded with a cellulose acetate membrane at 80 L / hr and a recovery rate of 75%. Free chlorine 0.5 mg-Cl ₂ / L was detected from the first RO-treated water. Sodium hydroxide (NaOH) was added to the first RO-treated water to adjust the pH to 10, and then water was passed through the activated carbon tower under the condition of SV20hr- ¹ . The activated carbon-treated water was then passed through a second RO membrane separation apparatus loaded with a polyamide membrane under conditions of 60 L / hr and a recovery rate of 92% (the pH of the second RO feed water was 9.5). In addition, the safety filter was provided in the front | former stage of the 1st RO membrane separator.

<Comparative Example 1>
In the same manner as in Example 1, NaClO was added to the waste water, and then the water was passed through a filter in the same manner, and the water subjected to the coagulation filtration was passed through the activated carbon tower under the condition of SV20hr- ^1. After performing the desterilizing agent treatment, the decalcification treatment was performed by passing water through the softening tower under the condition of SV16hr- ¹ . After NaOH was added to the softening tower treated water to adjust the pH to 9.5, water was passed through the RO membrane separator filled with the polyamide membrane under the conditions of 73 L / hr and a recovery rate of 75%. A safety filter was provided at the front stage of the RO membrane separator.

<Comparative Examples 2 and 3>
In Example 1, the first RO treated water pH was adjusted to 6 (Comparative Example 2) or 8.5 (Comparative Example 3), that is, the pH of the second RO feed water was 6 (Comparative Example 2) or 8.5. The treatment was performed under the same conditions as in Example 1 except that (Comparative Example 3) was used.

<Viable count>
The number of viable bacteria at each point in the treatment of Example 1 and Comparative Examples 1 to 3 was examined, and the results are shown in Table 1.

From Table 1, the following is clear.
In Example 1, while the number of viable cells is not observed at all measurement points, 10 ⁵ cells / ml with activated charcoal column treatment water in Comparative Example 1, ¹⁰⁶ at the softening column treated water / ml and slime breeding is doing. Further, it has been observed viable cells 10 about ⁴ cells / ml at the 2RO membrane treatment steps later, the activated carbon column as a de fungicides processing means has become a breeding ground for slime breeding in Comparative Examples 2 and 3 Became clear.

<Differential pressure of security filter>
In the process of Example 1, the change over time of the differential pressure between the safety filter provided in the previous stage of the first RO membrane separation apparatus and the safety filter provided in the previous stage of the RO membrane separation apparatus in the process of Comparative Example 1 was examined. Is shown in FIG.
As is apparent from FIG. 3, in Example 1, no increase in the differential pressure of the safety filter was observed.
On the other hand, in Comparative Example 1, the differential pressure reached about 0.2 MPa in 7 days of water flow, and the safety filter replacement frequency had to be frequently changed once / week. Also, slime adhesion was observed from the blocked security filter.

<Differential pressure of the second RO membrane>
Changes over time in the differential pressure of the RO membrane of the second RO membrane separation apparatus in the processing of Example 1 and Comparative Examples 2 and 3 were examined, and the results are shown in FIG.
As is clear from FIG. 4, in Example 1, an increase in the differential pressure of the second RO membrane is not observed. On the other hand, in Comparative Examples 2 and 3, a differential pressure of about 0.3 MPa occurred in one month of water flow.

<Processed water quality>
The water quality (TOC) of the treated water obtained in Example 1 and Comparative Examples 1 to 3 was as shown in Table 2.

  From Table 2, it turns out that there is no big difference in Example 1 and Comparative Examples 1-3 about the quality of the treated water.

<Discussion>
From the above results, according to the present invention, even in the organic matter-containing wastewater containing a large amount of hardness component, after reducing the hardness component without using the ion exchange resin tower, the organic matter is reduced using the RO membrane separator. By doing so, it prevents the slime breeding (biofouling) that occurs in the recovery system and prevents the RO membrane flux from decreasing, and at the same time performs stable treatment at the same time, and effectively reduces the TOC concentration in water. It can be seen that high quality treated water can be obtained.

It is a systematic diagram which shows embodiment of the organic substance processing method and organic substance processing apparatus of this invention. It is a graph which shows the relationship between the pH of 1st RO water supply of Experimental example 1, and Mg and Na removal rate. It is a graph which shows the time-dependent change of the differential pressure | voltage of the safety filter of Example 1 and Comparative Example 1. It is a graph which shows the daily change of the differential pressure | voltage of the 2nd RO membrane of Example 1 and Comparative Examples 2 and 3. FIG.

Explanation of symbols

1 Raw Water Tank 2 First RO Membrane Separator 3 Treated Water Tank 4 Activated Carbon Tower 5 Second RO Membrane Separator

Claims (10)

In the organic matter processing method of removing organic matter in the water by passing the organic matter-containing water through the RO membrane separator,
A bactericidal agent addition step of adding a bactericidal agent to water containing organic matter,
A first RO membrane treatment step of passing the treated water that has undergone the disinfectant addition step through a first RO membrane separation device having a hardness component removal function and oxidation resistance;
An alkali addition step of adding an alkali to the treated water that has undergone the first RO membrane treatment step to bring the pH to 9.5 or higher;
A disinfectant removing step for removing a disinfectant remaining in the treated water that has undergone the alkali addition step;
A second RO membrane treatment step of treating the treated water that has undergone the disinfectant removal step with an RO membrane treatment method.   2. The organic matter treatment method according to claim 1, further comprising a pH adjustment step of adjusting the pH to 4 to 6 by adding a pH adjuster to the organic matter-containing water before the first RO membrane treatment step.   3. The organic matter treatment method according to claim 1 or 2, further comprising a suspended matter removing step of removing suspended matter in the organic matter-containing water after the disinfectant adding step.   4. The organic material treatment method according to claim 1, wherein the RO membrane of the first RO membrane separation device is a cellulose acetate membrane.   5. The scale inhibitor addition step according to claim 1, wherein a scale inhibitor is added to the treated water that has undergone the first RO membrane treatment step at least 5 times the amount of calcium ions in the treated water. And the organic substance processing method characterized by processing the water to which the scale inhibitor was added in a 2nd RO membrane processing process. In an organic matter processing apparatus that removes organic matter in the water by passing the organic substance-containing water through the RO membrane separator,
A disinfectant addition means for adding a disinfectant to water containing organic matter,
A first RO membrane separation device having hardness component removal function and oxidation resistance, through which treated water of the disinfectant addition means is passed;
An alkali addition means for adding an alkali to the treated water of the first RO membrane separation device to bring the pH to 9.5 or higher;
A bactericidal agent removing means for removing a bactericidal agent remaining in the treated water of the alkali adding means;
An organic matter processing apparatus comprising: a second RO membrane separation device through which treated water of the disinfectant removing means is passed.   7. The organic substance processing apparatus according to claim 6, further comprising a pH adjusting means for adjusting the pH to 4 to 6 by adding a pH adjusting agent to the organic substance-containing water before the first RO membrane processing means.   8. The organic matter processing apparatus according to claim 6 or 7, further comprising a suspended substance removing unit that removes suspended matter in the organic substance-containing water after the disinfectant adding unit.   9. The organic matter processing apparatus according to claim 6, wherein the RO membrane of the first RO membrane separation device is a cellulose acetate membrane.   In any 1 item | term of the Claims 6 thru | or 9, It has a scale inhibitor addition means to add the scale inhibitor more than 5 weight times of the calcium ion in this treated water to the treated water of a 1st RO membrane separator. An organic substance processing apparatus, wherein water to which a scale inhibitor is added is processed by a second RO membrane separation apparatus.

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