JP2005218983A - Wastewater treatment method and apparatus using electrolytic oxidation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wastewater treatment method and apparatus using electrolytic oxidation, wherein even wastewater containing organic matter and nitrogenous matter in high concentrations can be treated in a high removal ratio and a high electric power efficiency. <P>SOLUTION: The wastewater treatment apparatus one comprising an electrolytic cell 10 partitioned with an ion-exchange membrane 13 into an anode zone 14 where a pollutant comprising organic matter and nitrogenous matter contained in raw wastewater is oxidatively decomposed with an electrolytically formed chlorine-ion-containing oxidizing substance and a cathode zone 15 where the treated water sent from the anode zone 14 and containing a residual oxidizing substance is reduced, wherein a membrane module 35 capable of separating chloride ions is provided downstream of the cathode zone 15, and a line 27 is provided to return the chlorine-ion-containing treated water separated from the water treated with the membrane module 35 to the anode zone 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wastewater treatment method for decomposing and removing pollutants such as BOD (biochemical oxygen consumption), COD (chemical oxygen consumption) and TN (total nitrogen) contained in wastewater by electrolysis. And an apparatus.

Domestic wastewater such as sewage, human waste, septic tank sludge, etc. or factory wastewater contains pollutants such as organic matter (BOD, COD) and nitrogen (TN), and these pollutants are environmental and ecosystem. Strict discharge standards are established because they affect
Various wastewater treatment technologies have been developed and put to practical use in order to satisfy this discharge standard, but the treatment technology by electrolytic oxidation is widely spread because it requires almost no chemicals and the treatment time is short.

Electrolytic treatment of wastewater is based on direct oxidation of organic matter on the electrode surface and indirect oxidation with the generated oxidizing substance by placing electrodes facing each other in an electrolytic cell storing wastewater and applying a voltage between the electrodes. The principle is to decompose and remove pollutants.
In the electrolytic treatment method, organic substances are decomposed and removed mainly by hypochlorous acid or hypochlorite ions having strong oxidizing power generated by electrolysis, and nitrogen content is nitrate nitrogen, nitrate nitrogen, nitrogen nitrite and nitrogen. The gas is decomposed and the waste water is purified (for example, Patent Document 1: Japanese Patent Laid-Open No. 7-110466).

Japanese Patent Application Laid-Open No. 9-155359 (Patent Document 2) discloses a method of electrolytically oxidizing COD-containing water using an electrolytic cell equipped with a diaphragm as shown in FIG.
The electrolytic cell 52 has a cathode chamber formed on the cathode 53 side and an anode chamber formed on the anode 55 side with a diaphragm 58 made of an MF membrane (microfiltration membrane), and contains COD introduced into the cathode chamber. After generating hydroxide ions from raw water by electrolysis, electrolytic oxidation is performed while supplying ozone in the anode chamber. Thereby, since the raw water has a high pH, oxidative decomposition in the anode chamber is promoted.
Furthermore, in JP-A-2001-79544 (Patent Document 3), after the treated water is filtered and ion exchange treated, the treated water mixed with hydrogen peroxide or sodium hypochlorite generated by electrolysis is irradiated with ultraviolet rays. Oxidative decomposition.

Japanese Patent Application Laid-Open No. 7-100466 Japanese Patent Laid-Open No. 9-155359 JP 2001-79544 A

However, when the concentration of organic substances and nitrogen contained in the wastewater is high, or when it is desired to improve the removal rate of these pollutants, the amount of oxidizing substances produced must be kept high, and the amount produced is high. As a result, there is a problem that oxidizing substances, that is, chlorine ions such as hypochlorite ions remain in the treated wastewater.
In the Japanese Patent Laid-Open No. 2001-79544, the salt produced by the ultraviolet irradiation is returned to the electrolytic cell and circulated. However, in this method, the salinity flowing out is separated from the treated water only by the salt recovery device. The load applied to the apparatus becomes large and the durability is poor, so it is not suitable for long-term continuous operation. In addition, the main component is oxidative decomposition by ultraviolet irradiation. However, the ultraviolet lamp consumes a large amount of power, and depending on the state of the waste water, it lacks permeability, so the decomposition efficiency is poor.

Furthermore, in order to increase the production amount of the oxidizing substance, it is necessary to increase the electric power supplied to the electrolytic cell, which increases the power consumption and increases the running cost.
Therefore, in view of the problems of the prior art, the present invention is a wastewater treatment method using electrolytic oxidation that can achieve a high removal rate even in wastewater containing a high concentration of organic matter and nitrogen, and can improve power efficiency. And an apparatus.

Therefore, in order to solve this problem, the present invention provides:
The electrolytic cell is partitioned into an anode area and a cathode area by an ion exchange membrane, and organic substances contained in the water to be treated and pollutants consisting of nitrogen are oxidized by an oxidizing substance containing chlorine ions generated electrolytically in the anode area. A wastewater treatment method for decomposing and reducing an oxidizing substance remaining in the cathode region,
The treated water discharged from the cathode region is subjected to membrane separation by a membrane module capable of separating chlorine ions, and the separated chlorine ion-containing treated water is returned to the anode region.

According to this invention, since the anode region and the cathode region are divided by the ion exchange membrane, the reaction in the bipolar region is efficiently performed. Moreover, since the excess oxidizing substance which is not consumed by oxidative decomposition is reduced in the cathode region, the load on the membrane module provided in the subsequent stage can be reduced.
In addition, in the electrolytic production of oxidizing substances such as hypochlorite ions and hypochlorous acid, the higher the chloride ion concentration in the anode region, the higher the production efficiency. In the present invention, chloride ions separated by the membrane module are used. Since treated water containing chlorine-based ions such as hypochlorite ions is returned to the anode region and circulated, a large amount of oxidizing substances can be generated in the anode region.

Therefore, the present invention can be applied to wastewater having a high organic matter and nitrogen concentration, and also in the case where it is desired to improve the treatment aqueous state.
Furthermore, since the chlorine ion is separated from the treated water discharged out of the system by the membrane module, the influence on the environment can be reduced.
In addition, although the said membrane module can utilize a reverse osmosis membrane (RO membrane), ultrafiltration (UF membrane), etc., it is good to use a RO membrane suitably. Furthermore, it is preferable to adjust the conditions of the RO membrane so that the chlorine-based ion concentration in the anode region has a suitable value.

In addition, the treated water extracted from the anode region is guided to a second electrolytic cell, and after the pollutant is mainly oxidatively decomposed in the second electrolytic cell, the treated water is introduced into the cathode region of the electrolytic cell, It is characterized mainly by reduction of chlorine-based ions.
Furthermore, the voltage value applied to the electrolytic cell is set to a value suitable for electrolytic oxidation of the pollutant contained in the water to be treated, and the voltage value applied to the second electrolytic cell is used for the reduction reaction of the oxidizing material. It is good to control each to an appropriate value independently.

In general, the voltage suitable for electrolytic oxidation of the pollutant is different from the voltage suitable for reduction of chlorine-based ions. Therefore, if the treatment is performed simultaneously in a single electrolytic cell, either reaction may be insufficient. .
Therefore, the electrolytic cell that mainly performs the oxidative decomposition reaction of the pollutant as in the invention is different from the electrolytic cell that mainly performs the reduction reaction of the chlorine-based ions, and each has a voltage value suitable for these reactions. By independently controlling the above, the reaction can be sufficiently caused and the power consumption can be suppressed.

In addition, the electrolytic cell is partitioned into an anode region and a cathode region by an ion exchange membrane, and an organic substance contained in the water to be treated and a pollutant composed of nitrogen content by an oxidizing substance containing chlorine ions generated electrolytically in the anode area. A wastewater treatment method for reducing oxidative substances remaining in the cathode region,
A first step of introducing the water to be treated into an adsorption tower for selectively adsorbing and separating the pollutant, and introducing the pollutant into the anode region after adsorbing and separating the pollutant;
A treatment system comprising: a second step of introducing an oxidizing substance-containing treated water extracted from the anode region to the adsorption tower, and introducing the contaminated substance carried on the adsorption tower into the cathode area after oxidative decomposition. It is characterized by being repeated.

This invention introduces the water to be treated before being supplied to the electrolytic cell into the adsorption tower to previously adsorb and separate the pollutant, and oxidatively decomposes the remaining pollutant in the electrolytic cell, The treated water containing the substance is guided to the adsorption tower, and the polluted substance carried thereon is oxidized and decomposed by the oxidizing substance.
In the adsorption tower, for example, an inorganic adsorbent having a porous structure such as zeolite or silicate, an adsorbent in which a metal catalyst such as Ti or Cu is supported on the inorganic adsorbent, or activated carbon or activated carbon fiber, etc. An adsorbent having a catalyst supported on the surface of an organic adsorbent is preferably used.

  According to this, the oxidative decomposition treatment of the pollutant and the reduction treatment of the oxidizable substance can each be configured in two stages, and each reaction can be sufficiently performed and the load on the apparatus can be reduced. In addition, since the adsorption tower is regenerated by passing the oxidizing substance-containing treated water, it is possible to set a longer maintenance interval such as replacement of the adsorbent and cleaning.

Further, the treatment target water is introduced into a plurality of adsorption towers with a time difference, and waste water is continuously treated by simultaneously performing the first step and the second step in different adsorption towers. .
In this way, continuous processing is possible by alternately performing processing in a plurality of adsorption towers, and improvement in processing efficiency can be expected.
Further, it is preferable that the treated water discharged from the cathode region is subjected to membrane separation by a membrane module capable of separating chlorine ions, and the separated chlorine ion-containing treated water is returned to the anode region. Thereby, the outflow of the chlorine content outside the system can be prevented.

Furthermore, as an invention of an apparatus for suitably carrying out the invention,
An anode region in which the inside of the first electrolytic cell is partitioned by an ion exchange membrane, an organic substance contained in the water to be treated by an oxidizing substance containing chlorine-based ions generated electrolytically, and a pollutant consisting of nitrogen are oxidatively decomposed; A wastewater treatment apparatus for forming a cathode region for reducing the remaining oxidizing substances by introducing treated water from the region,
A membrane module capable of separating chlorine-based ions is provided on the downstream side of the cathode region, and a line is provided for returning the chlorine-based ion-containing treated water separated from the treated water by the membrane module to the anode region. And

In addition, a second electrolytic cell is provided on a line for supplying treated water from the anode region to the cathode region,
A voltage having a different voltage value is applied to the first electrolytic cell and the second electrolytic cell, the pollutant is mainly oxidized and decomposed in the second electrolytic cell, and the oxidized material is mainly oxidized in the first electrolytic cell. It is characterized in that each is set to a voltage value for reducing the active substance.
Means for controlling the voltage value applied to the first electrolytic cell to a value suitable for reduction of chlorine-based ions based on the chlorine-based ion concentration in the treated water discharged from the second electrolytic cell; And a means for controlling the voltage value applied to the second electrolytic cell to a value suitable for oxidative decomposition of the pollutant based on the concentration of organic matter in the treated water discharged from the second electrolytic cell. To do.

Further, the electrolytic cell is partitioned with an ion exchange membrane, and an anode region that oxidizes and decomposes organic matter contained in the water to be treated with an oxidizing substance containing chlorine-based ions generated electrolytically, and a pollutant composed of nitrogen, and the anode region A waste water treatment apparatus for forming a cathode region for reducing the remaining oxidizing substances by introducing treated water from
An adsorption tower group provided with a plurality of adsorption towers for selectively adsorbing and separating the contaminants;
A return line for introducing the treated water introduced into the anode region through the one adsorption tower to the other adsorption tower; a supply line for introducing the treated water introduced into the other adsorption tower to the cathode area; Provided,
The treatment target water is introduced into the plurality of adsorption towers with a time difference, and the pollutant material carried on the adsorption tower is oxidatively decomposed with the chlorine ion-containing treated water from the return line.

  Furthermore, a membrane module capable of separating chlorine ions is provided on the downstream side of the cathode region, and a line is provided for returning the chlorine ion-containing treated water separated from the treated water by the membrane module to the anode region. It is characterized by that.

As described above, according to the present invention, since the anode region and the cathode region are divided by the ion exchange membrane, the reaction in both electrode regions is efficiently performed. Moreover, since the excess oxidizing substance which is not consumed by oxidative decomposition in the cathode region is reduced, the load on the membrane module provided in the subsequent stage can be reduced.
In addition, by returning chlorine-based ions to the anode region, it becomes possible to produce a large amount of oxidizing substances in the anode region and to minimize the discharge of chlorine-based ions out of the system. The impact on the environment is small.

Moreover, in the cathode region, these reduction reactions are mainly performed due to the presence of hypochlorite ions or hypochlorous acid, and the electrolytic potential can be made lower than the hydrogen generation reaction that has been mainly performed on the cathode side. Efficiency is improved.
Furthermore, by providing the second electrolytic cell or the adsorption tower, the oxidative decomposition reaction or the reduction reaction can be configured in two stages, the load applied to each apparatus is reduced, and the apparatus life is extended.
Therefore, according to this invention, even in wastewater containing a high concentration of organic matter and nitrogen, a high removal rate can be achieved without leaking an oxidizing substance out of the system, and power efficiency can be increased.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

1 to 3 and FIG. 6 are system diagrams of a wastewater treatment apparatus according to first to fourth embodiments of the present invention, and FIGS. 4 and 5 are diagrams illustrating a flow of treated water of the wastewater treatment apparatus according to the third embodiment. FIG.
This embodiment is suitable for the treatment of domestic wastewater such as sewage and human waste, septic tank sludge, or organic factory wastewater, and removes organic matter (COD, BOD, etc.) and nitrogen (TN) in wastewater. The purpose is to purify.

As shown in FIG. 1, a wastewater treatment apparatus 100A according to Example 1 of the present invention includes an electrolytic cell 10 partitioned by an ion exchange membrane 13, and an anode member 11 and a cathode member 12 that are disposed to face each other in the electrolytic cell 10. The power source 34 connected to both electrodes and the membrane module 35 located on the downstream side of the electrolytic cell 10 are the main components.
The electrolytic cell 10 is divided into an anode region 14 and a cathode region 15 by the ion exchange membrane 13, and water to be treated is introduced into the anode region 14, and treated water that has passed through the anode region 14 is supplied by a supply line 26. It is fed to the cathode area 15.

Further, the treated water that has passed through the cathode region 15 is introduced into the membrane module 35, and the chlorine-based ion-containing treated water separated here is introduced into the anode region 14 together with the treatment target water through a return line 27.
The membrane module 14 has a function of separating at least chloride ions among separation membranes such as a reverse osmosis membrane (RO membrane) and an ultrafiltration membrane (MF), and an RO membrane is preferably used.

In Example 1, hypochlorite ions are generated mainly by the following reaction formula (1) in the anode region 14 into which the water to be treated is introduced.
Cl ⁻ + 2OH ⁻ → ClO ⁻ + H ₂ + H ₂ O + 2e ⁻ (1)
In the anode region 14, in addition to hypochlorite ions, oxidizing substances such as hypochlorous acid (HClO), hydrogen peroxide (H ₂ O ₂ ), and hydroxy radicals (OH.) Having strong oxidizing power are contained. Generate.

In the anode region 14, the oxidizing substance reacts with the organic substance and nitrogen to convert the organic substance into carbon dioxide gas etc. according to the following reaction formula (2) and the like, and nitrogen is harmless according to the following reaction formula (3) and the like. Nitrogen gas is used to reduce the organic matter content and nitrogen content in the treated water.
2C ₆ H ₅ NH ₂ + 31ClO ⁻ → N ₂ + 7H ₂ O + 12CO ₂ + 31Cl ⁻
... (2)
2NH ₃ + 3ClO ⁻ → N ₂ + 3H ₂ O + 3Cl ⁻ (3)

Further, the oxidizing substance generated in the anode region 14 and not consumed by the oxidative decomposition is introduced to the cathode region 15 through the supply line 26 while being contained in the treated water. In the cathode region 15, for example, the following reaction formula (4) Reduced to chloride ions.
ClO ⁻ + H ₂ O + 2e ⁻ → Cl ⁻ + 2OH ⁻ (4)
Then, the chloride ion-containing treated water discharged from the cathode region 15 is introduced into the membrane module 35, and the chlorine ion-containing treated water is separated and discharged out of the system.
On the other hand, the chlorine ion-containing treated water is returned to the anode region 14 through a return line 27.

As a result, the chlorine ion concentration in the anode region 14 can be maintained high, the production efficiency of oxidizing substances such as hypochlorite ions and hypochlorous acid can be improved, and chlorine to the outside of the system can be improved. Prevent outflow of system ions.
In addition, hydrogen is usually generated in the cathode region 15, but when hypochlorite ions or hypochlorous acid is present, these reduction reactions are mainly performed together with nitric acid and nitrite ions. Since the potential of the reduction reaction of hypochlorite ions occurs at a lower potential than that of the hydrogen production reaction, the electrolysis voltage can be lowered and the energy efficiency is improved.
In addition, it is preferable to set the conditions of the membrane module 14 so that the anode region 14 has a chlorine ion concentration that efficiently generates an oxidizing substance.

FIG. 2 shows a wastewater treatment apparatus 100B according to a second embodiment of the present invention, and this apparatus has a configuration in which the electrolytic cells 10 shown in the first embodiment are arranged in multiple stages.
The electrolytic cells 10a and 10b have the same configuration, and are partitioned by ion exchange membranes 13a and 13b, and cathode regions including anode regions 14a and 14b having anode members 11a and 11b and cathode members 12a and 12b. A first electrolysis apparatus A and a second electrolysis apparatus B are formed from 15a and 15b.

The water to be treated is first introduced into the anode region 14a of the first electrolysis apparatus A, and after performing the electrolytic generation reaction of the oxidizing substance and the oxidative decomposition reaction of the pollutant substance, the anode of the second electrolysis apparatus B is obtained. It leads to the zone 14b and performs the same reaction. Then, the treated water extracted from the anode region 14b is introduced into the cathode region 15b of the second electrolytic cell B through the supply line 28, and the oxidizing substance remaining in the treated water is reduced.
The treated water discharged from the cathode region 15b is returned to the cathode region 15a of the first electrolysis apparatus A through the return line 29, where the oxidizing substance is reduced again.
The treated water that has been subjected to a series of treatments in this way is discharged after separating chlorine ions via the membrane module 25. On the other hand, the separated chlorine ion-containing treated water is returned to the anode region 14a of the first electrolysis apparatus A.

In addition, the wastewater treatment apparatus 100B includes, on the supply line 28, a TOC detection means 31 that measures the TOC (total organic carbon content) concentration of treated water discharged from the anode region 14b of the second electrolysis apparatus B; A control device 30 is provided for controlling the voltage value applied to the second electrolysis device B based on the measured TOC concentration.
Furthermore, on the return line 29, chloride ion detecting means 33 for measuring the chloride ion concentration discharged from the cathode region 15b of the second electrolysis apparatus B, and the first ion concentration based on the measured chloride ion concentration. A control device 32 for controlling the voltage value applied to the electrolysis device A is provided.

In the second embodiment, the oxidative decomposition reaction of the pollutant is performed mainly in the second electrolysis apparatus B, and the reduction reaction of the oxidizing substance contained in the treated water before the discharge is focused in the first electrolysis apparatus A. It is configured to perform automatically.
Therefore, the TOC detection means 31 grasps the state of pollutant decomposition, and the control device 30 controls the power supply voltage of the second electrolysis apparatus B so as to obtain the desired treated water quality, while the chloride ion detection means. The reduction state of the chlorine ion is grasped by 33, and the power supply voltage of the first electrolyzer A is controlled so that the chlorine ion concentration in the treated water becomes a predetermined value or less. Thereby, while being able to produce reaction enough, since only the voltage required for each reaction is applied independently, power consumption can be suppressed.

3 to 5 show a wastewater treatment apparatus 100C according to Embodiment 3 of the present invention.
As shown in FIG. 3, the wastewater treatment apparatus 100 </ b> C includes an electrolytic cell 10 in which an anode region 14 and a cathode region 15 are formed by an ion exchange membrane 13 as in the first and second embodiments, and the electrolytic cell 10. The main components are the anode member 11 and the cathode member 12, which are disposed to face each other, a power source 34 connected to these electrodes, and two or more adsorption towers 16A and 16B arranged in parallel on the upstream side of the electrolytic cell 10. . For the adsorption towers 16A and 16B, for example, an inorganic adsorbent in which a zeolite or silicate is formed in a porous structure, an adsorbent in which a metal catalyst such as Ti or Cu is supported on the inorganic adsorbent, or activated carbon or activated carbon An adsorbent having a catalyst supported on the surface of an organic adsorbent such as fiber is preferably used.

  Further, valves 18 and 19 provided on a line for branching the water to be treated and supplying it to the adsorption towers 16A and 16B, and the treated water that has passed through the adsorption tower 16A are fed into the anode region 14 and the cathode region 15 of the electrolytic cell 10. The valves 20 and 21 provided on the line 26 to be branched and introduced, and the valves 22 and 23 similarly provided on the line for branching and introducing the treated water from the adsorption tower 16B to the electrolytic cell 10; And valves 24 and 25 provided on a line for returning the treated water extracted from the anode region 14 to the adsorption towers 16A and 16B.

Next, the treatment flow of the water to be treated in the wastewater treatment apparatus 100C will be described based on FIG. 4 and FIG.
In the treatment process shown in FIG. 4, first, the valve 19 is closed and the valve 18 is opened to supply water to be treated to the adsorption tower 16A, and a part of the pollutant in the treated water is adsorbed by passing through the adsorption tower 16A. Then, the valve 21 is closed and the valve 20 is opened to introduce the treated water into the anode region 14 of the electrolytic cell 10.
After the pollutant is decomposed and removed by the oxidizing substance generated electrolytically in the anode region 14, the valve 24 is closed, the valve 25 is opened, and the treated water extracted from the anode region 14 is returned to the adsorption tower 16B.

  The adsorbing tower 16B holds the pollutant by passing through the water to be treated in advance, and the pollutant is oxidized by the oxidizing power of the oxidizing substance remaining in the treated water by passing the return treated water through. Decomposes and reduces oxidizing substances. Then, the valve 22 is closed, the valve 23 is opened, and the treated water that has passed through the adsorption tower 16B is supplied to the cathode region 15, and after reducing the oxidizing substance in the cathode region 15, it is discharged.

After a predetermined time has passed after performing such processing steps, the processing steps are switched to the processing steps shown in FIG. First, the valve 19 is opened, the valve 18 is closed and the water to be treated is introduced into the adsorption tower 16B, and the pollutant adsorbed during the treatment step shown in FIG. 4 is oxidized and decomposed, and the adsorbent is reduced and regenerated. The valve 23 is closed, the valve 22 is opened, and the treated water that has passed through the adsorption tower 16 </ b> B is supplied to the anode region 14.
Then, the pollutant is decomposed and removed while electrolytically generating the oxidizing substance in the anode region 14, the valve 24 is opened, the valve 25 is closed, and the treated water extracted from the anode region 14 is returned to the adsorption tower 16A.

In the adsorption tower 16A, the pre-supported pollutant is oxidatively decomposed with an oxidizing substance contained in the treated water, and after reducing and regenerating the adsorbent, the valve 21 is opened and the valve 20 is closed. Treated water discharged from 16A is introduced into the cathode region 15. The treated water introduced into the cathode region 15 is discharged after reducing the contained oxidizing substance.
Such processing steps are continuously performed by alternately performing with a time difference.
Thereby, the oxidative decomposition treatment of the pollutant and the reduction treatment of the oxidizing substance can each be configured in two stages, and each reaction can be sufficiently performed and the load on the apparatus can be reduced. In addition, since the adsorption tower is regenerated by the flow of the oxidizing substance-containing treated water, it is possible to set a long maintenance interval such as replacement of the adsorbent and cleaning.

Moreover, it is good also as a structure which comprised the membrane module 35 in the wastewater treatment apparatus 100C which has the structure similar to the said Example 3 like Example 4 of this invention shown by FIG. In the wastewater treatment apparatus 100D, the description of the parts having the same configuration as in the third embodiment is omitted.
The wastewater treatment apparatus 100D is provided with a membrane module 35 on the downstream side of the cathode region 15, discharges treated water from which chlorine ions have been separated by the membrane module 35, and treats the treated water containing the chlorine ions as described above. It is configured to return to the anode region 14.
As a result, the outflow of chlorine ions to the outside of the system can be minimized, and further, the chlorine ion concentration in the anode region 14 can be kept high, so that the generation efficiency of the oxidizing substance is improved. The pollutant can be treated with a high removal rate.

  Although this embodiment is suitable for the treatment of wastewater containing a large amount of organic matter (COD, BOD, etc.) and nitrogen (TN), conventional solid-liquid separation devices, biological treatment devices, advanced water treatment devices, etc. Can be applied to the treatment of wastewater having various harmful substances.

It is a systematic diagram of the waste water treatment apparatus concerning Example 1 of this invention. It is a systematic diagram of the waste water treatment apparatus concerning Example 2 of this invention. It is a systematic diagram of the wastewater treatment apparatus concerning Example 3 of this invention. It is explanatory drawing which shows the process of the waste water treatment apparatus which concerns on FIG. It is explanatory drawing which shows another process process of FIG. It is a systematic diagram of the wastewater treatment apparatus concerning Example 4 of this invention. It is a block diagram which shows the conventional electrolysis tank.

Explanation of symbols

10, 10a, 10b Electrolytic cell 11, 11a, 11b Anode member 12, 12a, 12b Cathode member 13, 13a, 13b Ion exchange membrane 14, 14a, 14b Anode region 15, 15a, 15b Cathode region 16A, 16B Adsorption tower 30, 32 Control device 31 TOC detection means 33 Chloride ion detection means 34 Power supply 35 Membrane module

Claims (11)

The electrolytic cell is partitioned into an anode area and a cathode area by an ion exchange membrane, and organic substances contained in the water to be treated and pollutants consisting of nitrogen are oxidized by an oxidizing substance containing chlorine ions generated electrolytically in the anode area. A wastewater treatment method for decomposing and reducing an oxidizing substance remaining in the cathode region,
Utilizing electrolytic oxidation, characterized in that treated water discharged from the cathode region is subjected to membrane separation by a membrane module capable of separating chlorine ions, and the separated chlorine ion-containing treated water is returned to the anode region Wastewater treatment method.   The treated water extracted from the anode region is guided to a second electrolytic cell, and after the pollutant is mainly oxidatively decomposed in the second electrolytic cell, the treated water is introduced into the cathode region of the electrolytic cell and mainly chlorine. The wastewater treatment method using electrolytic oxidation according to claim 1, wherein the reduction of system ions is performed.   The voltage value applied to the electrolytic cell is suitable for the electrolytic oxidation of the pollutant contained in the water to be treated, and the voltage value applied to the second electrolytic cell is suitable for the reduction reaction of the oxidizing substance. 3. The wastewater treatment method using electrolytic oxidation according to claim 2, wherein each value is controlled independently. The electrolytic cell is partitioned into an anode area and a cathode area by an ion exchange membrane, and organic substances contained in the water to be treated and pollutants consisting of nitrogen are oxidized by an oxidizing substance containing chlorine ions generated electrolytically in the anode area. A wastewater treatment method for decomposing and reducing an oxidizing substance remaining in the cathode region,
A first step of introducing the water to be treated into an adsorption tower for selectively adsorbing and separating the pollutant, and introducing the pollutant into the anode region after adsorbing and separating the pollutant;
A treatment system comprising: a second step of introducing an oxidizing substance-containing treated water extracted from the anode region to the adsorption tower, and introducing the contaminated substance carried on the adsorption tower into the cathode area after oxidative decomposition. A wastewater treatment method using electrolytic oxidation, which is performed repeatedly.   The treatment water is introduced into a plurality of adsorption towers with a time difference, and waste water is continuously treated by simultaneously performing the first step and the second step in different adsorption towers. 4. A wastewater treatment method using electrolytic oxidation according to 4.   5. The treated water discharged from the cathode region is subjected to membrane separation by a membrane module capable of separating chlorine ions, and the separated chlorine ion-containing treated water is returned to the anode region. Wastewater treatment method using electrolytic oxidation of An anode region in which the inside of the first electrolytic cell is partitioned by an ion exchange membrane, an organic substance contained in the water to be treated by an oxidizing substance containing chlorine-based ions generated electrolytically, and a pollutant consisting of nitrogen are oxidatively decomposed; A wastewater treatment apparatus for forming a cathode region for reducing the remaining oxidizing substances by introducing treated water from the region,
A membrane module capable of separating chlorine-based ions is provided on the downstream side of the cathode region, and a line is provided for returning the chlorine-based ion-containing treated water separated from the treated water by the membrane module to the anode region. Wastewater treatment equipment using electrolytic oxidation. A second electrolytic cell is provided on a line for supplying treated water from the anode region to the cathode region,
A voltage having a different voltage value is applied to the first electrolytic cell and the second electrolytic cell, the pollutant is mainly oxidized and decomposed in the second electrolytic cell, and the oxidized material is mainly oxidized in the first electrolytic cell. The wastewater treatment apparatus using electrolytic oxidation according to claim 7, wherein each is set to a voltage value for reducing the active substance.   Means for controlling the voltage value applied to the first electrolytic cell to a value suitable for reduction of chlorine ion based on the chlorine ion concentration in the treated water discharged from the second electrolytic cell; And a means for controlling the voltage value applied to the electrolytic cell to a value suitable for oxidative decomposition of the pollutant based on the concentration of organic matter in the treated water discharged from the second electrolytic cell. Item 9. A wastewater treatment apparatus using electrolytic oxidation according to Item 8. The inside of the electrolytic cell is partitioned by an ion exchange membrane, and an anode region that oxidizes and decomposes organic matter contained in the water to be treated by the oxidizing substance containing chlorine-based ions generated by electrolysis and a pollutant composed of nitrogen, and from the anode region A wastewater treatment apparatus for forming a cathode region for introducing treated water and reducing remaining oxidizing substances,
An adsorption tower group provided with a plurality of adsorption towers for selectively adsorbing and separating the contaminants;
A return line for introducing the treated water introduced into the anode region through the one adsorption tower to the other adsorption tower; a supply line for introducing the treated water introduced into the other adsorption tower to the cathode area; Provided,
Utilizes electrolytic oxidation, which introduces water to be treated into multiple adsorption towers with a time lag, and oxidizes and decomposes pollutants carried on the adsorption tower with chlorine ion-containing treated water from the return line. Wastewater treatment equipment.   A membrane module capable of separating chlorine-based ions is provided on the downstream side of the cathode region, and a line is provided for returning the chlorine-based ion-containing treated water separated from the treated water by the membrane module to the anode region. A wastewater treatment apparatus using electrolytic oxidation according to claim 10.

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