KR20100007811A - Wastewater treatment method and system - Google Patents

Abstract

PURPOSE: A wastewater treatment method and a wastewater treatment system thereof are provided to treat change of water quality without an adjusting bath, and to process the drainage of the concentration by adjusting the water to be processed. CONSTITUTION: A wastewater treatment method includes the following steps: adjusting water(4) to be processed by mixing clean water(2) with drainage(1) which is not processed; detecting a concentration index of the water to be processed while setting up the missed amount of the clean water; and controlling the discharge amount of the clean water. The wastewater treatment method further includes a step for reducing the concentration index of the water with an oxidizer absorbed water(3), and a step for supplying an electrolyte to an oxidizer producing device(7).

Description

Wastewater treatment method and system

The present invention relates to wastewater treatment methods and systems that are particularly suitable for relatively high concentrations of wastewater.

Conventionally, there are drainage of a liquid crystal factory, kitchen drainage, and various other drainages. These drainages were originally clean water, but after use, they are contaminated with organic components or the like.

Like this, there are various kinds of drainages, but the quantity and quality of water fluctuate according to the day or time. For example, on the same day, depending on the time of day, the COD (chemical oxygen demand) is high, which is close to 2,000 ppm, and when it is low, it exceeds 1,000 ppm. Therefore, in the treatment, the adjustment tank (Patent Literature 1, Japanese Patent Laid-Open No. 11-347596) can be averaged and diluted to a predetermined concentration that can be treated (in the case of biological treatment, the COD is about 500 ppm). Gazette) is stored for a day. In other words, if the amount to be treated every day 1,000 tons, 1000 to + + size adjustment tank (feet) is installed and put there. In this way, even if the COD fluctuates from 1,000 to 2,000ppm, the water quality is gradually averaged during storage in the adjusting tank, so that the next day is about 1,500ppm at any position. In this way, if the treatment is averaged and then treated, the treatment can be stabilized by reducing the influence of up-down of the wastewater original water quality and water quality over time.

However, there is a problem that the adjustment tank requires a large pit in order to store the drainage, and there is a problem that even if the adjustment tank is used, the water quality at the time of treatment may fluctuate because of daily fluctuations.

It is an object of the present invention to provide a wastewater treatment method and system capable of absorbing daily fluctuations in water quality without necessarily requiring an adjustment tank.

In order to solve the above problems, the present invention has been made the following technical means.

(1) In the wastewater treatment method of the present invention, the clean water after the treatment is fed back to the wastewater before the treatment and mixed to adjust the water to be treated according to this treatment method, and the mixed amount of the clean water after the treatment to the wastewater before the treatment is the wastewater treatment. In the above aspect, while setting the concentration index and the flow rate of the water to be treated to be within a predetermined range suitable for the treatment, the concentration index of the water to be treated is detected by a sensor so that the concentration index of the water to be treated is within the predetermined range. It is characterized by controlling the amount of feedback of the clean water after the drainage treatment and the amount of discharge from the treatment system.

Here, as an aspect of wastewater treatment, a biological treatment, a treatment by electrolysis, a treatment of adding an oxidizing agent (sodium hypochlorite, etc.) can be exemplified. Examples of the concentration index include COD (chemical oxygen demand), BOD (biochemical oxygen demand), TOC, T-N, n-hexane, and the like.

According to this wastewater treatment method, the "clean water after treatment" (for example, COD 1000 to 2000 ppm) is fed back and mixed with the "clean water after treatment (for example, less than 5 ppm COD)", and the "treatment target" by the treatment method is used. Water is adjusted, and the mixed amount of "clean water after treatment" with respect to "drainage before treatment" is regarded as "water to be treated with respect to the aspect of the wastewater treatment (bio treatment or treatment by electrolysis). And the concentration indicators of "drainage before treatment", "clean water after treatment" and "water to be treated" are detected by a sensor (e.g., a COD system) while setting the concentration index and the flow rate within a predetermined range suitable for the treatment. The amount of gained amount of "clean water after treatment" in the "drainage before treatment" such that the concentration index of the "water to be treated" becomes a predetermined index (for example, COD 50 to 100 ppm in the treatment by electrolysis or addition of an oxidizing agent). And this processing system Because of the control to the discharge, and thereby reduce an effect of a treatment with a variation of a multiple of the original self-concentration to achieve a seamless process as hayeoseo feeding back the clean water after the treatment process can adjust the destination. In addition, clean water after treatment is used for adjustment, which can save water resources and contribute to environmental problems.

In this case, when the sensor detects the concentration index of the wastewater before treatment and the clean water after the treatment in addition to the water to be treated, the concentration index of the original wastewater and the clean water discharged from the treatment system can be grasped. .

By the way, when the treatment mode is electrolysis, electrolytes such as salts are dissolved in the drainage to provide an appropriate conductivity so that the electric current flows as necessary, and the oxidation of the anodic oxidation and the generated OH radicals is performed. The COD is reduced by oxidatively decomposing the organic components contained in the drainage, for example. The pH at the time of treatment (treatment) of the water to be treated is adjusted to a range in which oxidation action such as hypochlorous acid generated by electrolysis is strong. The treatment according to this electrolysis is different from the biological treatment, so there is an advantage that sludge (sludge) does not come out while oxidative decomposition takes place in an instant.

(2) an oxidizing agent generating electrolytic apparatus for generating hypohalogenic acid by electrolyzing water containing an electrolyte, and reducing the concentration index by bringing the oxidant-containing water generated by the oxidizing agent producing electrolytic apparatus to the water to be treated; The electrolyte separated from the clean water after the treatment and fed back to the wastewater before treatment may be supplied to the oxidizer generating electrolytic apparatus.

Here, sodium chloride (salt), sodium bromide, etc. can be illustrated as said electrolyte. As water containing the electrolyte, for example, seawater can be used. Examples of the hypohalogen acid include hypochlorous acid and hypobromic acid. As means for separating the electrolyte, an RO membrane, an ion exchange resin, an electrodialysis, or an ion separator can be used.

In this manner, the oxidant-containing electrolysed water generated by the oxidant-producing electrolyzer is passed to the water to be treated, and the concentration indicator is reduced. Then, the electrolyte is separated from the clean water after the treatment and fed back to the wastewater before treatment. As a result, the electrolyte is separated from the clean water after the treatment which is fed back into the waste water before the treatment, and the concentration of the electrolyte can be avoided from accumulating and increasing during the treatment. Since the separated and recovered electrolyte is supplied to the oxidant generating electrolyzer, the electrolyte contained in the oxidant-containing water can be circulated to the oxidant generating mechanism and used effectively.

(3) The wastewater treatment system of the present invention includes a treatment tank for treating wastewater and a return passage for feeding back clean water after the treatment, and feeds and mixes clean water after treatment in the treatment tank via the return passage to the wastewater before treatment. Adjust the number of treatment targets, and set the mixing amount of the clean water after the treatment to the wastewater before treatment so that the concentration index and the flow rate of the treatment target water are within a predetermined range suitable for the treatment with respect to the aspect of the wastewater treatment. The concentration index is detected by a sensor, and the feedback amount of the clean water after the treatment to the drainage channel before the treatment and the discharge amount from the treatment system are controlled so that the concentration index of the water to be treated is within a predetermined range.

This wastewater treatment system has the same function as the wastewater treatment method. Here, in the treated water tank which supplies the waste water and performs the treatment, tap water (or clean water after the last treatment) may be stored at the start of the treatment (because it is not the clean water after the treatment).

The present invention consists of the configuration as described above has the following effects.

Adjusting the treated water by feeding back the purified water after treatment can reduce the effect on the treatment due to the fluctuations in the concentrations of the original drainage, and thus, the adjustment tank is not necessary and also absorbs the daily fluctuations in the water quality. can do.

There are plant drainage, kitchen drainage and other various wastewaters, and the treatment methods include biotreatment, flocculation sedimentation, electrolysis treatment, treatment with addition of an oxidizing agent (sodium hypochlorite, etc.) and the degree of contamination of the drainage. Concentration indicators for evaluating BOD (biochemical oxygen demand), COD (chemical oxygen demand), TOC, TN, n-hexane and the like.

By the way, the amount of water and water quality fluctuate fluently depending on time and time. For example, in the case of a LCD television manufacturing plant, the operating conditions of the production facilities vary greatly depending on the demand environment of the society such as sales. Even if the planned production is performed, a large amount of drainage occurs at 100% operation. In some cases, the situation may be almost closed. In addition, the amount of drainage varies considerably even during times of high water usage and low times of water usage due to the large number of people. Here, a large pit is excavated as a storage tank for drainage (a considerable site area is required), and drainage is stored in this pit to achieve as much as possible averaging and equalizing the quantity and quality of water. Water quality is surprisingly variable. Therefore, in actual treatment, the BOD concentration or the COD concentration was too high or too low to perform proper treatment. In other words, the drainage was not completely purified.

For this reason, a large number of large evaporators are installed side by side, each of them drains again to liquefy by evaporating (high concentration organic components are concentrated rather than evaporated) and then again liquefied (high concentration organic components are reduced). While the COD is reduced to some extent, the disposal of the evaporated wastes as wastes is being carried out while the biological treatment is carried out. Is required.

This wastewater treatment method and system was conceived based on the premise that the quantity and water quality of the waste water fluctuate, and how to reduce and absorb the fluctuation.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

Embodiment 1

This wastewater treatment method feeds back the mixed wastewater before treatment (COD 1000 to 2000 ppm) 1 and clean water after the treatment (less than 5 ppm COD, preferably almost 0 ppm) (2), and mixes this treatment method (oxidant-containing water ( (3) is adjusted to oxidatively decompose by adding sodium hypochlorite. Furthermore, in this embodiment, although the wastewater of 1000-2000 ppm of COD was processed, the wastewater of any density | concentration, for example, high concentration wastewater, such as COD 300000 ppm, is applicable.

On the other hand, this wastewater treatment system is a device of the above-described wastewater treatment method, and includes a treatment water tank 5 to treat wastewater and a return passage 6 for feeding back clean water 2 after the treatment, and draining water before treatment. In step (1), the purified water 2 after the treatment in the treated water tank 5 is fed back through the return flow path 6 to be mixed to adjust the water to be treated 4. The purified water 2 after the treatment is fed back and mixed with the wastewater 1 before the treatment to adjust the treated water 4, but external clean water such as tap water may be mixed together (not shown).

The mixed amount of the clean water 2 after the treatment with respect to the waste water 1 before the treatment is treated with water (4) with respect to the aspect of the wastewater treatment (addition of oxidizing agent, electrolytic treatment, biological treatment, etc.). The concentration index (COD) of the wastewater 1 before the treatment, the clean water 2 after the treatment, and the water to be treated 4 are set so that the concentration index (COD) and the flow rate are set to a predetermined range suitable for the treatment. The concentration index of the water to be treated (4) can be set to a predetermined range (for example, COD of 50 to 100 ppm in the treatment by electrolysis or addition of an oxidant, and in the case of biological treatment, about 400 to 600 ppm is preferable. The feedback amount A of the clean water 2 after treatment to the wastewater 1 before treatment and the discharge amount B from the treatment system are controlled. In addition, the sensor of the density | concentration indicator of the waste water 1 before processing is shown by S1, the sensor of the density | concentration indicator of the clean water 2 after processing is shown by S2, and the sensor of the density | concentration indicator of the water to be treated 4 is represented by S3.

By the way, the predetermined range in which the concentration index (COD) and the flow rate of the water to be treated 4 are suitable for the treatment is specified in the specific specifications of the treatment apparatus (electrolysis or oxidizing agent) or treatment facility (biotreatment or flocculation sedimentation). Therefore it is different. In other words, in the treatment by the electrolysis or the addition of the oxidizing agent, the range of COD 10-20 ppm other than the above COD is suitable, depending on the specification and the accident method of the apparatus. That is, when the predetermined range of the concentration index of the water to be treated (4) is set to a low concentration range (COD 10 to 20 ppm), there is an advantage that it is possible to further reduce and absorb variations such as water quality of the waste water. On the other hand, when the predetermined range of the concentration index of the water to be treated (4) is set to 50 to 100 ppm COD, there is an advantage that the total amount of processing can be reduced by reducing the feedback amount of the clean water (2) after treatment. Even so, there is clearly a predetermined range in which the concentration index (COD) and the flow rate of the water to be treated (4) are suitable for the treatment in consideration of the specifications or the way of thinking of the treatment apparatus or treatment facility.

When the concentration range (COD) of the water to be treated (4) and the predetermined range suitable for the treatment are C0D 50 to 100 ppm, the basic setting is the amount of wastewater (1000 to 2000 ppm) 1 before treatment (1). The amount of the treated water (COD50 to 100 ppm) (4) was adjusted by feeding back the amount 19 of the treated clean water (preferably less than 5 ppm of COD, preferably almost 0 ppm) (2), and adding hypochlorous acid. The amount 1 of the clean water 2 after the oxidative decomposition treatment in (5) is discharged out of the treatment system, but the feedback amount A and the discharge amount B from the treatment system are variably controlled in accordance with the change in the water quality. That is, when the concentration indicator COD of the water to be treated (4) is detected to be higher than the predetermined concentration range (50 to 100 ppm) by the COD system as a sensor, the amount of feedback (A) is increased while reducing the discharge amount (B) from the processing system. To control. On the contrary, if the concentration index COD of the water to be treated 4 is detected to be lower than the predetermined concentration range 50 to 100, the control unit is controlled to increase the discharge amount B from the processing system while reducing the feedback amount A. FIG.

In addition, this embodiment uses a treatment method of adding sodium hypochlorite (oxidizing agent) as described above, and includes an oxidizing agent generating electrolytic mechanism 7 which generates hypohalogenous acid by electrolyzing water containing an electrolyte. (8) is an electrolytic electrode. Then, the oxidant-containing electrolyzer 7 causes the oxidant-containing water 3 to reach the treated water 4 (in this embodiment, to be injected into the return flow path 6) to reduce the concentration index. In the electrolyte separation means 9 is fed back to the separation of the electrolyte from the clean water 2 after the treatment, and mixed with the drainage 1 before the treatment, and the separated and recovered electrolyte is supplied to the oxidant generating electrolysis apparatus 7. Do it. Since the amount of water supplied to the oxidant generating electrolytic apparatus 7 as the electrolyte is reduced in the clean water 2 after the treatment, the tap water may be replenished with the return flow path 6 so as to replenish the loss.

Examples of the electrolyte include sodium chloride (salt), sodium bromide, and the like. As water containing the electrolyte, for example, seawater can be used. Examples of the hypohalogen acid include hypochlorous acid and hypobromic acid. As the electrolyte separation means 9, an RO membrane, an ion exchange resin, an electrodialysis, or an ion separator may be used.

In the treated water tank 5 which performs the drainage treatment, since the purified water 2 does not yet exist at the start of treatment, the tap water or the clean water 2 after the previous treatment may be stored. In the case where ss components and the like are mixed in the drainage, filtration is performed in advance by a sand filtration device or the like.

Next, the state of use of the wastewater treatment method and system of this embodiment will be described.

According to this wastewater treatment method and system, the wastewater before treatment (COD 1000 to 2000 ppm) 1 is fed back and mixed with clean water 2 (after COD less than 5 ppm, preferably almost 0 ppm) after the treatment (oxidant). The water to be treated 4 is adjusted by the addition of phosphorus sodium hypochlorite and subjected to oxidative decomposition, and the mixed amount of the clean water 2 after the treatment with respect to the waste water 1 before the treatment is the aspect of the wastewater treatment (addition of oxidizing agent). Method, electrolytic treatment, biological treatment method, etc.), while setting the concentration index and the flow rate of the water to be treated within a predetermined range suitable for the treatment, the concentration index of the water to be treated 4 is measured by the sensor. Feedback amount A of clean water 2 after treatment to the wastewater 1 before treatment so that the concentration index of the water to be treated 4 is detected by (COD system) to be within a predetermined range (COD 50 to 100 ppm) and the treatment Because we let you control discharge (B) from system By adjusting the treatment target water 4 by feeding back the clean water 2 of Lihu, the adjustment tank is not necessarily necessary and the water treatment can be performed smoothly by reducing the influence of the treatment due to the variation of the concentration of the original drainage itself. It has the advantage of being able to absorb daily fluctuations. In addition, the clean water (2) after treatment is used for the adjustment, which can save water resources and contribute to environmental problems.

Then, the oxidant-containing electrolyzer 7 causes the oxidant-containing water 3 to reach the water to be treated 4 to reduce the concentration index, and then clean water after treatment in the electrolyte separation means 9. Since the electrolyte was separated from (2) and fed back into the wastewater 1 before treatment, the electrolyte was separated from the clean water 2 after treatment to be fed back and mixed into the wastewater 1 before treatment. It can be avoided that the electrolyte concentration of the object water 4 increases cumulatively during the treatment. Since the separated and recovered electrolyte is supplied to the oxidizer generating electrolyzer 7, there is an advantage that the electrolyte contained in the oxidant-containing water 3 can be circulated to the oxidant generating mechanism to effectively use the oxidant.

In addition, since the clean water 2 after treatment is reduced in the concentration of the pollution assessment index as described above (COD 5 ppm), it can be reused for various purposes, which has the advantage of contributing to environmental problems through the provision of water resources. . In addition, there is an advantage that can be directly processed in real time without collecting the waste water 1 before the treatment tank.

Embodiment 2

In this embodiment, the embodiment of the drainage treatment is electrolysis (not shown), and when necessary, such as when the conductivity of the drainage is low, the electrolyte, such as salt, is dissolved in the drainage so as to impart an appropriate conductivity so that a current flows and the anodic oxidation thereof. The organic component contained in the waste water is oxidatively decomposed according to the oxidative action of the generated OH radical or the like to reduce the COD. The pH at the time of treatment (treatment) of the water to be treated is adjusted to a range in which oxidation action such as hypochlorous acid generated by electrolysis is strong.

Specifically, an electrolytic electrode is inserted into the treatment tank so that the electrolysis can be directly electrolyzed by adding an electrolyte such as a salt to the electrolysis degree of the treatment water. The treatment by the electrolysis is different from the biological treatment, there is an advantage that the residue does not come out while oxidative decomposition is carried out instantaneously.

The adjustment tank is not necessary because the feed water is fed back to the treated water and the treated water is adjusted to reduce the effects of the fluctuations in the concentrations of the original drainage itself. It can be absorbed and applied and applied to water treatment of liquid crystal plant drainage, kitchen drainage and other various drainages.

1 is a flowchart illustrating an embodiment of a wastewater treatment system of the present invention.

*** Description of the symbols for the main parts of the drawings ***

One; Drain before treatment

2; Clean water after treatment

3; Oxidant-containing water

4; Number of treatment

5; Treatment tank

6; Return euro

7; Oxidizing agent

Claims (3)

The purified water 2 after the treatment is fed back to the wastewater 1 before the treatment and mixed to adjust the treated water 4 according to this wastewater treatment method, and the purified water 2 after the treatment with respect to the wastewater 1 before the treatment. The mixing amount of is set so that the concentration index of the water to be treated 4 and the flow rate are in a predetermined range suitable for the treatment with respect to the aspect of the drainage treatment, and the concentration index of the water to be treated 4 is detected by the sensor. A wastewater treatment method characterized by controlling the amount of feedback of clean water (2) after treatment to wastewater (1) before treatment and the discharge amount from the treatment system so that the concentration index of water (4) falls within a predetermined range. The oxidant-containing water (3) produced by the oxidant generating electrolytic apparatus (7) is provided with an oxidant generating electrolytic mechanism (7) for electrolytically decomposing water containing an electrolyte to produce hypohalogenate. The electrolyte that was separated and recovered while mixing with the wastewater 1 before the treatment by feeding back the treated water to the treated water 4 and reducing the concentration index thereof, and feeding back the separation of the electrolyte from the purified water 2 after the treatment. A wastewater treatment method for supplying to a production electrolyzer (7). And a return flow passage 6 for feeding back the treated water tank 5 for treating the waste water and the purified water 2 after the treatment, and the purified water 2 after the treatment in the treated water tank 5 is disposed in the waste water 1 before the treatment. The amount of the treated water 4 is adjusted by feeding back through the return flow path 6 to mix, and the mixed amount of the clean water 2 after the treatment with respect to the waste water 1 before the treatment is the amount of treated water with respect to the aspect of the waste water treatment. While setting the concentration index and flow rate of (4) to be within a predetermined range suitable for processing, the concentration index of the water to be treated 4 is detected by a sensor so that the concentration index of the water to be treated 4 is within a predetermined range. A wastewater treatment system characterized by controlling the amount of feedback of clean water (2) after treatment to wastewater (1) before treatment and the amount of discharge from the treatment system.

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