JP2007160233A - Organic matter-containing wastewater treatment apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable stabilization and efficiency improvement of advanced treatment, and efficient recovery of treated water of high quality by reducing the amount of biometabolites produced in a biological treatment process when treating organic matter-containing wastewater by biological treatment before the advanced treatment, such as membrane separation, to reduce the amount of an organic matter flowing into an advanced treatment process at the subsequent stage. <P>SOLUTION: Biologically treated water of No. 1 aeration tank 11 is subjected to coagulation treatment, and then subjected to solid-liquid separation in No. 1 settling tank 14. The obtained separated water is biologically treated in No. 2 aeration tank 21. The biologically treated water is subjected to coagulation treatment, and then subjected to solid-liquid separation in No. 2 settling tank 24. Subsequently membrane separation treatment is carried out in an RO membrane separator 40 as an advanced treatment means. Two stages of biological treatment and solid-liquid separation are carried out before the advanced treatment means, which removes the organic matter sufficiently, and makes treatment by the advanced treatment means stable and efficient. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a treatment apparatus and treatment method for organic matter-containing wastewater, and in particular, the amount of organic matter flowing into the advanced treatment step when wastewater containing organic matter is biologically treated and then subjected to advanced treatment to collect treated water. The present invention relates to an apparatus and a method for stabilizing and improving the efficiency of advanced treatment by reducing the amount of water and efficiently recovering high-quality treated water.

  In recent years, recycling of water resources has been regarded as important, and wastewater has been treated and collected actively. In particular, membrane separators with fine pore sizes, such as ultrafiltration (UF) membranes and reverse osmosis (RO) membranes, can remove high molecular weight organic substances and provide high quality treated water. Have been widely used. On the other hand, since these membrane separators have a small pore size, if the inflowing organic substance concentration increases, the organic substance tends to accumulate on the membrane surface, and the filtration resistance increases remarkably, making it difficult to pass water. Become. In such a case, it is effective for the stable treatment to install a biological treatment device in front of the membrane separation device and reduce the concentration of organic substances in the waste water prior to the membrane separation treatment.

  When biological treatment is performed before the membrane separation treatment as described above, for example, as shown in FIG. 2, the organic matter-containing wastewater is biologically treated in the aeration tank 11, and the flocculant is added to the biological treatment water by adding a flocculant. The agglomerated water is separated into solid and liquid in the sedimentation tank 14, the obtained separated water is filtered with the filtration device 30, and the filtered water is subjected to membrane separation treatment with the RO membrane separation device 40. Such an organic substance-containing wastewater treatment apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-238152.

  However, even if easily biodegradable organic substances are treated in the biological treatment process preceding the membrane separation treatment, metabolites of persistent microorganisms are produced in the order of several percent in the process of decomposing organic substances in the wastewater. This is included in the biologically treated water. These metabolites are mainly produced from the process in which microbial bodies produced by the decomposition of organic substances in raw water are decomposed by the food chain between microorganisms, but many of them are relatively high in molecular weight and have a high concentration. If it rises, it will cause the membrane surface of the membrane separator to be blocked. Therefore, even when a biological treatment device is installed in the front stage of the membrane separation device, the concentration of the produced biometabolite also increases as the organic substance concentration in the wastewater increases, so that stable operation of the membrane separation device gradually increases. There was a tendency to be difficult.

In addition, as an advanced treatment for water recovery, even when an organic substance is removed by ion exchange resin or oxidation treatment, the increase in the concentration of organic substances in the water used in the advanced treatment process is the resin used for the ion exchange resin. This was an element that hindered stabilization of the treatment, leading to an increase in the amount, an increase in the exchange frequency of the ion exchange resin, and an increase in the amount of oxidant used.
JP-A-2005-238152

  The present invention reduces the amount of biological metabolites generated in the biological treatment process when the biological treatment is performed before the advanced treatment such as membrane separation treatment to treat the wastewater containing organic matter, and flows into the advanced treatment process in the subsequent stage. An object of the present invention is to provide an organic matter-containing wastewater treatment apparatus and treatment method that can reduce the amount of organic matter to stabilize and improve the efficiency of advanced treatment and efficiently recover high-quality treated water.

  The apparatus for treating organic matter-containing wastewater of the present invention (Claim 1) is a first biological treatment means for biologically treating organic matter-containing wastewater, and a first liquid-separated biologically treated water flowing out from the first biological treatment means. 1 solid-liquid separation means, second biological treatment means for biologically treating the separated water separated by the first solid-liquid separation means, and biologically treated water flowing out from the second biological treatment means It has the 2nd solid-liquid separation means to isolate | separate, and the high processing means which removes the dissolved substance contained in the separated water isolate | separated by this 2nd solid-liquid separation means, It is characterized by the above-mentioned.

  The organic substance-containing wastewater treatment apparatus according to claim 2 is characterized in that, in claim 1, the advanced treatment means is a membrane separation apparatus.

  An organic matter-containing wastewater treatment apparatus according to claim 3 is the organic matter-containing wastewater treatment apparatus according to claim 1 or 2, wherein the organic matter-containing wastewater is disposed between the first biological treatment means and the first solid-liquid separation means and / or the second biological treatment means. Between the 2nd solid-liquid separation means, it has a coagulation tank which adds a coagulant | flocculant to biological treatment water and performs a coagulation reaction, It is characterized by the above-mentioned.

  The method for treating organic matter-containing wastewater according to the present invention (Claim 4) is a first biological treatment step for biologically treating organic matter-containing wastewater, and a first method for solid-liquid separation of biologically treated water flowing out from the first biological treatment step. 1 solid-liquid separation step, a second biological treatment step for biologically treating the separated water separated in the first solid-liquid separation step, and a biologically treated water flowing out from the second biological treatment step It has the 2nd solid-liquid separation process to isolate | separate, and the advanced treatment process which removes the dissolved substance contained in the separated water isolate | separated by this 2nd solid-liquid separation process, It is characterized by the above-mentioned.

  The method for treating wastewater containing organic matter according to claim 5 is characterized in that, in claim 4, the advanced treatment step is a membrane separation step.

  The method for treating wastewater containing organic matter according to claim 6 is the method according to claim 4 or 5, wherein the first biological treatment step and the first solid-liquid separation step and / or the second biological treatment step. Between the 2nd solid-liquid separation process, it has the aggregation process which adds a flocculant to biological treatment water and performs aggregation reaction.

  According to the present invention, the microorganisms produced by the first biological treatment means are separated by the first solid-liquid separation means after most of the soluble organic substance is decomposed by the first biological treatment means. The separated water from which the body has been removed is further biologically treated by the second biological treatment means, and then the microbial bodies produced by the second biological treatment means are separated by the second solid-liquid separation means. Thus, by performing the two-stage treatment of biological treatment and solid-liquid separation, the amount of biological metabolites can be reduced, the concentration of organic substances flowing into the advanced treatment means can be reduced, and stable wastewater treatment can be performed.

  And the water from which the organic substance was fully removed can be further advanced to obtain treated water with good water quality. Since the treated water of this advanced treatment means has extremely good water quality, it can be recovered as it is as reused water or as raw water of pure water or ultrapure water.

  In addition, the advanced treatment means treats water with a sufficiently reduced concentration of organic substances, so the load of advanced treatment is reduced. If the advanced treatment means is a membrane separation device, membrane contamination is prevented and flux over time is reduced. Thus, stable treatment can be continued for a long time. In addition, in the case of an ion exchange device, it is possible to improve the quality of treated water, reduce the frequency of resin regeneration, and reduce the frequency of resin exchange by reducing organic load and organic contamination. In the case of an oxidizer, it is possible to reduce the amount of oxidant used and reduce the size of the device by reducing the organic load.

  Embodiments of the organic matter-containing wastewater treatment apparatus and the organic matter-containing wastewater treatment method of the present invention will be described in detail below.

[Organic wastewater]
In the present invention, the organic matter-containing wastewater to be treated is not particularly limited as long as it is an organic matter-containing wastewater that is normally biologically treated. Examples thereof include electronic industrial wastewater, chemical factory wastewater, and food factory wastewater. Can be mentioned. For example, in the electronic component manufacturing process, a large amount of various organic wastewater is generated from the development process, peeling process, etching process, cleaning process, etc., and the wastewater can be recovered and purified to a pure water level for reuse. As desired, these wastewaters are suitable as the wastewater to be treated in the present invention.

  Examples of such organic wastewater include organic wastewater containing isopropyl alcohol and ethyl alcohol, organic nitrogen such as monoethanolamine (MEA) and tetramethylammonium hydroxide (TMAH), and ammonia nitrogen. Organic waste water and organic waste water containing organic sulfur compounds such as dimethyl sulfoxide (DMSO) can be mentioned.

[Biological treatment]
Any biological treatment means for biologically treating the wastewater may be used as long as it is excellent in the decomposition efficiency of organic matter, and a known aerobic or anaerobic biological treatment type biological reaction tank can be used. For example, a floating method for holding activated sludge in a suspended state in a tank, a biofilm method for holding activated sludge attached to a carrier, and the like can be employed. The biofilm method may be any microbial bed method such as a fixed bed method, a fluidized bed method, and a developed bed method, and as the carrier, any of activated carbon, various plastic carriers, sponge carriers, and the like can be used.

  A sponge carrier is preferable as the carrier, and microorganisms can be maintained at a high concentration if the sponge carrier is used. The sponge material is not particularly limited, but ester polyurethane is preferable. There is no particular limitation on the amount of the carrier to be charged, but usually it is preferably about 10 to 50%, particularly preferably about 30 to 50% in terms of the apparent capacity of the carrier relative to the volume of the biological reaction tank.

  As an aerobic biological reaction tank that microbially decomposes organic matter in an aerobic state, an aeration tank provided with oxygen gas supply means such as an air diffuser for supplying oxygen (air) into the tank and an aerator is used. be able to.

  On the other hand, as an anaerobic biological reaction tank that microbially decomposes organic matter in an anaerobic state, an anaerobic tank holding a carrier and granular sludge can be used.

  The biological reaction tank may be an aerobic biological reaction tank or an anaerobic biological reaction tank, or an aerobic biological reaction tank and / or a multi-tank type anaerobic biological reaction tank. A partition wall may be provided. That is, in the present invention, multi-tank type ones can be used as the first biological treatment means and the second biological treatment means, respectively.

[Aggregation treatment]
The biologically treated water obtained by biologically treating the organic wastewater is preferably subjected to an agglomeration treatment prior to the solid-liquid separation in order to surely remove the microorganisms and the macromolecular organic material by the solid-liquid separation means at the subsequent stage. A normal aggregating apparatus is used for the agglomeration treatment of biologically treated water. The aggregation tank of this aggregation processing apparatus may be only one tank or two or more tanks may be provided in multiple stages.

  The agglomeration apparatus is generally composed of a rapid agitation tank for sufficiently bringing the aggregating agent into contact with the water to be treated and a slow agitation tank for growing the agglomeration floc. Accordingly, when two or more flocculation tanks are provided in multiple stages, it is preferable that the preceding flocculation tank be a rapid stirring tank and the latter flocculation tank be a slow stirring tank.

  Examples of the inorganic flocculant used in the agglomeration treatment include iron-based flocculants such as ferric chloride and polyiron sulfate, and aluminum-based flocculants such as aluminum sulfate, aluminum chloride, and polyaluminum chloride. Is preferably an iron-based flocculant. These inorganic flocculants may be used individually by 1 type, and may use 2 or more types together.

During the flocculation treatment, a pH adjusting agent is added as necessary to adjust the pH to be suitable for the inorganic flocculating agent used. That is, as a pH condition, for example, it is effective to react at a pH of 5.5 or less with an iron-based flocculant, and after reacting at a pH of 5.0 or less with an aluminum-based flocculant, the pH is adjusted to 6.0 or higher. Since it is effective, it is preferable to adjust the pH by adding an acid such as hydrochloric acid (HCl) or sulfuric acid (H ₂ SO ₄ ) or an alkali such as sodium hydroxide (NaOH) as necessary. Although the details of the reason why a good quality of treated water can be obtained by the aggregation treatment under such pH conditions are not clear, it is related to the neutralization of the charge of the protein component in the biological metabolite. Presumed.

  By the coagulation treatment, soluble organic matter and suspension in the biologically treated water are flocked. In order to grow this coagulation floc, an inorganic coagulant may be added in the first coagulation tank and a polymer coagulant may be added in the second coagulation tank.

[Solid-liquid separation]
The solid-liquid separation means of the agglomerated treated water obtained by agglomerating the biologically treated water, preferably the agglomerated treated water is not particularly limited, such as a sedimentation tank, a flotation tank, a centrifuge, etc. A pressure levitation tank is particularly preferable because it is easy to separate and an apparatus with a smaller area than the precipitation tank may be used. In particular, membrane separation means such as an immersion membrane may be used as the second solid-liquid separation means.

[Advanced processing]
The advanced treatment means may further remove dissolved organic matter remaining in the treated water obtained by removing the organic matter in the wastewater by the first and second biological treatment means and the first and second solid-liquid separation means. Moreover, the solvent salt contained in the treated water may be removed, or both may be removed.

Examples of advanced processing means include the following.
Membrane separator: RO, NF (nanofiltration), UF membrane, for example, for organic substance removal and desalting
Separation device, etc. Ion exchange device: for example, anion exchange resin tower, cation for desalting and organic matter removal
Ion exchange resin tower, mixed packing of cation exchange resin and anion exchange resin
Mixed bed tower, electric desalination equipment, etc. Oxidation equipment: For example, ozone oxidation equipment, hydrogen peroxide oxidation equipment, salt for organic matter removal
An oxygen oxidizer, an ultraviolet oxidizer or the like, or an oxidizer using both of them. In addition
In general, an apparatus such as ion exchange or membrane separation is provided downstream of the oxidation apparatus.
It is often done.

  These advanced processing means can be used in combination of two or more as appropriate. Moreover, you may further add other processing apparatuses, such as a filtration apparatus and an activated carbon processing apparatus, as some advanced treatment means.

  In particular, when an RO membrane separation device is used as the advanced treatment means, it is preferable to provide a filtration device in front of the RO membrane separation device to remove SS in the water. As the filtration device, a packed bed type filtration device filled with a filter medium such as sand or anthracite, a membrane filtration device using a membrane such as a microfiltration (MF) membrane, an ultrafiltration (UF) membrane, or the like can be used. .

[Organic wastewater treatment equipment]
An example of the organic matter-containing wastewater treatment apparatus of the present invention will be described below with reference to the drawings.

  FIG. 1 is a system diagram showing an embodiment of the organic matter-containing wastewater treatment apparatus of the present invention. In addition, FIG. 1 is an example of the processing apparatus of the organic substance containing waste_water | drain of this invention, Comprising: The processing apparatus of the organic substance containing waste_water | drain of this invention is not limited to what is shown in FIG. For example, the advanced treatment means is not limited to the RO membrane separation apparatus, but may be an ion exchange apparatus or an oxidation apparatus, and the biological treatment means is not limited to the aeration tank but may be an anaerobic biological reaction tank.

  This organic matter-containing wastewater treatment apparatus is equipped with an aeration tank (hereinafter referred to as “No. 1 aeration tank”) 11 as a first biological treatment means. A coagulation tank (hereinafter referred to as “No. 1-1 coagulation tank”) 12 and a coagulation tank (hereinafter referred to as “No. 1-2 coagulation tank”) that coagulate the biologically treated water from one aeration tank 11. No. 13). 1-2 First-stage treatment apparatus 10 comprising a precipitation tank (hereinafter referred to as “No. 1 precipitation tank”) 14 as a first solid-liquid separation means for solid-liquid separation of the agglomerated water from the agglomeration tank 13. No. which is treated water of the first stage treatment apparatus 10. An aeration tank (hereinafter referred to as “No. 2 aeration tank”) 21 as a second biological treatment means into which the separated water of the 1 sedimentation tank 14 is introduced. 2 Coagulation tanks (hereinafter referred to as “No. 2-1 coagulation tanks”) 22 and coagulation tanks (hereinafter referred to as “No. 2-2 coagulation tanks) arranged in two stages for coagulating the biologically treated water from the aeration tank 21. No. 23), No. 23. 2-2 Second-stage treatment apparatus 20 comprising a precipitation tank (hereinafter referred to as “No. 2 precipitation tank”) 24 as a second solid-liquid separation means for solid-liquid separation of the coagulated water from the coagulation tank 23. No. which is the treated water of the second stage treatment apparatus 20. 2 It is comprised with the filtration apparatus 30 into which the separation water of the sedimentation tank 24 is introduce | transduced, and RO membrane separation apparatus 40 as an advanced process means into which the filtration water of the filtration apparatus 30 is introduce | transduced.

  Raw water (organic matter-containing wastewater) is no. 1 It introduce | transduces into the aeration tank 11, and aerobic biological treatment is carried out under the aeration from the diffuser 11A. This No. In the 1 aeration tank 11, the concentration of the soluble organic substance flowing into the second aeration tank 21 in the subsequent stage is reduced by removing most of the soluble organic substance (S-TOC) in the raw water. Since the first aeration tank 11 is the first biological treatment tank, the BOD load amount per microorganism amount in the tank becomes high, and thus the progress of self-decomposition by the food chain between microorganisms is suppressed.

  No. Although the preferable operation mode of the 1 aeration tank 11 is slightly different depending on the decomposability of the organic substance contained in the raw water, the load amount from which 60 to 95%, more preferably 70 to 90% of the soluble organic matter in the raw water is removed. Is good. Further, from the viewpoint of suppressing the self-degradation of microorganisms, the value of SRT, which is a value obtained by dividing the amount of microorganisms retained by the amount of generation, is 5 days or less, more preferably 3 days or less, particularly 1 to 3 days. Good. The BOD sludge load for obtaining the above conditions is usually 0.5 to 10 Kg-BOD / Kg-VSS / day, more preferably 1.0 to 5.0 Kg-BOD / Kg-VSS / day.

No. When such a high-load operation is performed in one aeration tank 11, it is difficult to form a microorganism floc with good sedimentation. Therefore, as shown in the figure, it is preferable to introduce the carrier 11b into the tank so that the amount of microorganisms can be stably maintained. . The amount of retained sludge when the carrier is added differs depending on the carrier and the filling rate, but when the general sponge-like carrier is filled in an apparent volume of 30 to 50% of the tank volume, the sludge retention amount per aeration tank is 2500. Since it is about ˜6000 mg-VSS / L, 1.5-60 Kg-BOD / m ³ / day, particularly 2-30 Kg-BOD / m ³ / day is preferable as the tank load.

  No. The biologically treated water from the 1 aeration tank 11 is then No. 1. 1-1 After an inorganic flocculant was added in the flocculant tank 12 and the flocculant was treated, In the 1-2 coagulation tank 13, the pH adjusting agent and / or the polymer coagulant is added to coarsen the floc. 1 It feeds to the settling tank 14, and the aggregation floc is solid-liquid separated.

No. Next, the solid-liquid separated water in the settling tank 14 is No. 2 It is introduced into the aeration tank 21 and is subjected to aerobic biological treatment under aeration from the diffuser 12A. This No. In the 2 aeration tank 21, the soluble organic material remaining in the first-stage biological treatment is decomposed. This No. In the two-aeration tank 21, it is desirable that reliable decomposition proceeds so as to reduce the concentration of organic matter flowing into the RO membrane separation device 40, which is an advanced processing means in the subsequent stage, as much as possible. A preferable BOD sludge load is 0.01 to 0.30 Kg-BOD / Kg-VSS / day, and more preferably 0.05 to 0.2 Kg-BOD / Kg-VSS / day. This No. 2 The aeration tank 21 is preferably one that holds the carrier 22B in the tank so that the amount of microorganisms can be stably maintained even at a low load. This No. Bath load of 2 aeration tank ^{0.03~1.8Kg-BOD / m 3 / day} , particularly ^{0.15~1.2Kg-BOD} / m 3 / day is preferred. Moreover, it is preferable that SRT is 5 to 50 days.

  No. 2 The biologically treated water from the aeration tank 21 is then No. 2-1, after an inorganic flocculant was added in the agglomeration tank 22 for agglomeration treatment, In the 2-2 coagulation tank 23, a pH adjuster and / or a polymer coagulant is added to coarsen the floc. 2 The flocculated floc is fed to the settling tank 24 and separated into solid and liquid.

  No. 2 The solid-liquid separation water in the settling tank 24 is then subjected to RO membrane separation treatment by the RO membrane separation device 40 after the residual SS is removed by the filtration device 30, and the permeated water is taken out as treated water.

  In the apparatus of FIG. 1, high-quality treated water can be obtained by performing two stages of biological treatment and solid-liquid separation at the front stage of the RO membrane separation apparatus 40, and water with a low FI value can be separated by RO membrane separation. Since water can be supplied to the device 40, it is possible to suppress the decrease in membrane flux of the RO membrane separation device and to obtain treated water stably for a long period of time.

  The FI value is used as an index for determining whether or not the quality of water supplied to the RO membrane separation device when water is passed through the RO membrane separation device for deionization is suitable for the RO membrane treatment. Is. Even if the amount of dissolved organic matter and SS in the water is approximately the same, when the RO membrane treatment is performed, the membrane flux may or may not decrease early. In such a case, there is a difference in the FI value of the RO water supply. Has occurred.

  The FI value is obtained by performing an operation of measuring the time required to pass a sample amount of water through a membrane filter having a predetermined pore size and filtering a predetermined amount. It is used to determine whether the water quality is likely to cause membrane contamination or membrane clogging or is unlikely to occur. In general, water quality with an FI value of 5 or less may be permitted as RO water supply, but it is usually desired that the water quality has an FI value of 3 or less. Therefore, in the present invention, when an RO membrane separation device is used as an advanced treatment means, it is preferable to obtain water having an FI value of 3 or less by two-stage biological treatment and solid-liquid separation, and use this as water supply for the RO membrane separation device. .

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

[Example 1, Comparative Example 1]
Using the apparatus shown in FIG. 1 (Example 1) or FIG. 2 (Comparative Example 1), the following water quality factory effluent mainly composed of IPA (isopropyl alcohol) was used as raw water, and the treatment was performed at a treatment water amount of 1000 L / day. . In addition, since the shortage of nitrogen and phosphorus was assumed in this biological treatment of raw water, ammonium sulfate and phosphoric acid were added to the raw water so that TOC: N: P = 100: 15: 3. .
<Raw water quality>
S-TOC: 457 mg / L
Kj-N: 11.5mg / L
PO ₄ -P: 1.5 mg / L

Table 1 shows the specifications and processing conditions of the apparatuses used in Example 1 and Comparative Example 1.
Table 2 shows the water quality of each part, and Table 3 shows the daily change in the flux reduction rate of the RO membrane separator.
Table 4 shows the reaction tank area (assuming that the water depth of the aeration tank, the coagulation tank, and the precipitation tank is 4 m) per 1000 m ³ / day of treated water.

  From the above results, the following is clear.

  In Example 1, No. 1 in the previous stage was used. In the 1 aeration tank, most of the organic matter in the raw water was removed, and before the autolysis proceeded, the fungus body was designated as SS. It can be removed by solid-liquid separation in one precipitation tank. And No. 1 Separate the separated water from the sedimentation tank. 2 The remaining organic matter is decomposed to a higher degree by treating in an aeration tank and 2 By removing SS in the sedimentation tank, as a result, the total capacity of No. 2 smaller than the aeration tank capacity of Comparative Example 1 was obtained. Treated water with low S-TOC and SS can be obtained in 1 and 2 aeration tanks. In addition, since the coagulation treatment can be sufficiently performed in the coagulation tank with a small amount of coagulant added, The total amount of flocculant added in the 1 and 2 flocculants is also the same as in Comparative Example 1, and treated water suitable for membrane separation can be obtained. That is, the S-TOC value is low, and it is an index of the coagulation treatment effect, and treated water having a low FI value that serves as an index of the feed water quality of the membrane separation device is obtained and supplied to the RO membrane separation device. Treated water can be obtained.

It is a systematic diagram which shows embodiment of the processing apparatus of the organic substance containing waste_water | drain of this invention. It is a systematic diagram showing a conventional method.

Explanation of symbols

10 1st stage processing apparatus 11 No. 1 Aeration tank 12 No. 1-1 Coagulation tank 13 No. 1-2 Coagulation tank 14 No. 1 sedimentation tank 20 2nd stage processing apparatus 21 No. 2 Aeration tank 22 2-1. Coagulation tank 23 No. 2-2 Coagulation tank 24 No. 2 Precipitation tank 30 Filtration device 40 RO membrane separation device

Claims (6)

A first biological treatment means for biologically treating organic matter-containing wastewater;
First solid-liquid separation means for solid-liquid separation of biologically treated water flowing out of the first biological treatment means;
A second biological treatment means for biologically treating the separated water separated by the first solid-liquid separation means;
Second solid-liquid separation means for solid-liquid separation of biologically treated water flowing out from the second biological treatment means;
An organic matter-containing wastewater treatment apparatus comprising: an advanced treatment means for removing dissolved substances contained in the separated water separated by the second solid-liquid separation means.   2. The apparatus for treating organic matter-containing wastewater according to claim 1, wherein the advanced treatment means is a membrane separation device.   In claim 1 or 2, between the first biological treatment means and the first solid-liquid separation means and / or between the second biological treatment means and the second solid-liquid separation means, An apparatus for treating organic matter-containing wastewater, comprising a flocculation tank for adding a flocculant to biologically treated water to cause a flocculation reaction. A first biological treatment process for biologically treating organic matter-containing wastewater;
A first solid-liquid separation step for solid-liquid separation of the biologically treated water flowing out of the first biological treatment step;
A second biological treatment step for biologically treating the separated water separated in the first solid-liquid separation step;
A second solid-liquid separation step for solid-liquid separation of the biologically treated water flowing out of the second biological treatment step;
And an advanced treatment step of removing dissolved substances contained in the separated water separated in the second solid-liquid separation step.   5. The method for treating organic matter-containing wastewater according to claim 4, wherein the advanced treatment step is a membrane separation step.   In claim 4 or 5, between the first biological treatment step and the first solid-liquid separation step and / or between the second biological treatment step and the second solid-liquid separation step, An organic matter-containing wastewater treatment method comprising a coagulation step in which a coagulant is added to biologically treated water to cause an aggregation reaction.

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