KR20130064173A - System for treating organic wastewater having high nitrogen content - Google Patents

Abstract

The present invention provides an organic wastewater treatment system having a high nitrogen content, comprising: a methane fermentation tank for fermenting organic wastewater; An anaerobic tank for removing ammonia from the digestive leachate discharged from the methane fermentation tank; Electrolyte removal unit for removing nitrogen components by electrolysis of the treatment liquid discharged from the anaerobic tank; And it relates to an organic wastewater treatment system having a high nitrogen content to include a gas purification unit for purifying aeration gas generated from the anaerobic tank.
According to the present invention, by treating anaerobic wastewater with high nitrogen content, such as livestock wastewater and food waste wastewater, the digestive leachate (fermentation liquid) obtained in the methane fermentation process using anaerobic activated sludge method, especially ammonia state After the concentration of nitrogen is reduced, the removal of nitrogen components such as ammonia nitrogen and nitrogen nitrogen can be efficiently and reliably treated by an electrolytic denitrification method which is a post-treatment.

Description

System for treating organic wastewater having high nitrogen content

The present invention relates to an organic wastewater treatment system having a high nitrogen content, and more particularly, to treating a high concentration wastewater having a high nitrogen content such as a livestock wastewater and food waste wastewater, and treating anaerobic desorption liquid (fermented liquid) obtained in a methane fermentation treatment. The sludge method is used to reduce the amount of nitrogen in the methane fermentation solution, especially the concentration of ammonia nitrogen, and then to efficiently and reliably remove nitrogen components such as ammonia nitrogen and nitrogen acetate by the post-treatment electrolytic nitrogen removal method. It relates to an organic wastewater treatment system having a high content of nitrogen.

In general, the livestock wastewater discharged from livestock houses such as pigs and barns has a special characteristic that it has a lot of solid materials and high biochemical oxygen demand (dlgk, 'BOD') compared with the domestic wastewater discharged from a general household. A method using a treatment system combining a methane fermentation method suitable for high-load wastewater treatment such as livestock wastewater and an activated sludge method with excellent purification ability for livestock wastewater treatment has been proposed.

When methane fermentation is carried out by anaerobic microorganisms of organic wastes such as cattle and pigs, manure such as livestock waste and food waste, digested gas mainly composed of methane gas (CH ₄ ) and carbon dioxide gas (CO ₂ ), and fermentation residues. As a result, a treatment solution after fermentation of methane, that is, undigested organic matter, solid matter, suspended matter called SS, or suspended matter, that is, digestive desorption solution, is generated.

The methane fermentation method is mainly a method of decomposing organic matter into methane gas and carbon dioxide gas by the action of anaerobic microorganisms, and has the advantage that can be used as thermal energy by recovering methane gas, a decomposition product. Among these, digestive gas is utilized as energy useful for a gas use system, etc., but since the extinguishing leachate becomes an environmental pollutant except for the method used for liquid fertilization and compost, it is necessary to perform an appropriate purification treatment. In particular, in recent years, environmental pollution by nitrogen and phosphorus contained in the digestive desorbent has become serious, and it is urgent to establish a technology that can effectively treat the digestive detachment solution.

The activated sludge process continuously aerations the activated sludge, which is the flock of aerobic microorganisms, and the wastewater, and decomposes the organic matter in the wastewater into carbon gas and water by contacting the activated sludge with the wastewater, and has a low BOD value and high cleanness. There is an advantage in that a number can be obtained. However, the activated sludge method is not suitable for high-load treatment, and if the livestock wastewater of high concentration is treated as it is, there is a risk of reducing the activity of the activated sludge and killing microorganisms. In this case, if the digestion and decomposition of the livestock wastewater is advanced to some extent by the methane fermentation method suitable for high load wastewater treatment, the wastewater treatment utilizing the excellent purification ability of the activated sludge process can be realized.

1 is a block diagram showing a livestock wastewater treatment system according to the prior art.

As shown in FIG. 1, the conventional livestock wastewater treatment system 10 is a system for purifying digestive leachate by methane fermentation using an aerobic activated sludge method. The livestock wastewater discharged from livestock houses such as pig and barn After methane fermentation by the methane fermentation tank (11), the fermentation broth obtained by dehydration with the dehydrator (12) is stored in the fermentation broth (13), and the fermentation broth passing through the screen (14) is blown by the blower (15a). The aeration tank 15 to be supplied is purged with activated sludge while being aerated, and solids such as activated sludge are separated from the wastewater after the aeration treatment by sedimentation in the settling tank 16.

The conventional livestock wastewater treatment system 10 allows the organic solids in the wastewater to be digested to some extent in the methane fermentation tank 11 and extracts the fermentation broth from the dehydrator 12, and then once fermentation broth. After storage in the reservoir 13, the fermentation broth is transferred to the aeration tank 15 by a pump. Solids remaining in the fermentation broth are allowed to be removed from the screen 14. In addition, the wastewater purified by the activated sludge in the aeration tank 15 is guided to the settling tank 16 to settle and separate the mixed aerobic activated sludge and the like, and then discharge only the clean liquid above the settling tank 16. The activated sludge separated in the settling tank 16 is discharged by a pump, and the rest is discharged as surplus sludge.

However, the conventional livestock wastewater treatment system 10 has the following problems.

First, the methane fermentation liquid obtained in the methane fermentation process has a high ammonia concentration, there is a risk that may adversely affect the activity of the activated sludge present in the aeration tank. In general, the anaerobic treatment of proteins produces ammonia as a decomposition product, so that the ammonia nitrogen after methane fermentation increases more than the original wastewater. Livestock wastewater has a high concentration of 1,500 to 5,000mg / L of total nitrogen, and a high proportion of ammonia nitrogen derived from feces occupies the total nitrogen. For this reason, since the ammonia nitrogen concentration of the methane fermentation solution is very high, the ammonia inhibition effect in the aeration tank prevents the reduction of suspended solids concentration (SS) and BOD treatment by activated sludge.

Second, methane fermentation broth has a high total nitrogen content and a high ratio of BOD. For this reason, when the amount of air supplied from the aeration tank is excessive, the ammonia (NH ₃ ) is produced by acetic acid (NH ₃ ) and acetic acid (NO ₂ ) and acetic acid (NO ₃ ) by the microorganisms in the activated sludge. to above the denitrification to convert nitrogen gas (N _2), O occurs when the acetate and acetic acid accumulated in the aeration tank. As a result, there is a risk that the pH in the aeration tank is lower than the range suitable for the activity of the activated sludge, causing the wastewater to be treated poorly.

Third, the wastewater treatment capacity in the aeration tank is proportional to the amount of activated sludge. However, in the prior art, since the solid solution of the treated water flowing out of the aeration tank is treated by sedimentation in the sedimentation tank, in order to prevent deterioration of the clean liquid at the upper part of the sedimentation tank, the concentration of suspended solids (MLSS) in the aeration tank is too high. I can't. Originally, the MLSS of the aeration tank is set at about 2,000 to 5,000 mg / L. If this value is increased, the activated sludge increases, so that the processing capacity can be improved, but there is a possibility of adverse effects on the properties of the discharged clean liquid. have. Therefore, in order to increase the purification capability in the conventional treatment equipment, the capacity of the aeration tank must be increased.

Fourth, since the processing capacity of the aeration tank cannot be made too high, the BOD of the fermentation broth is very large, and when the concentration is high, it is necessary to dilute the fermentation broth in the aeration tank or before introducing into the aeration tank.

Fifth, the cleansing liquid obtained by solid-liquid separation by the sedimentation separation method in a sedimentation tank is easy to be affected by the inflow water amount of a sedimentation tank, and the property of activated sludge. That is, when the inflow of the sedimentation tank or the change in the properties of the activated sludge occurs, there is a risk of causing a poor treatment, such as an increase in the SS of the effluent.

Sixth, the discharged water discharged from the sedimentation tank contains a large amount of untreated ammonia nitrogen and acetic acid nitrogen, so that there is a sufficient risk of contaminating the environment.

In order to solve the conventional problems as described above, the present invention treats high concentration wastewater with high nitrogen content, such as livestock wastewater, food waste wastewater, etc., and uses the anaerobic activated sludge process as the digestive leachate (fermented liquid) obtained in the methane fermentation treatment. By reducing the amount of nitrogen in the methane fermentation solution, especially the concentration of ammonia nitrogen, the removal of nitrogen components such as ammonia nitrogen and nitric acid acetate is efficiently and reliably treated by post-treatment electrolytic nitrogen removal. Therefore, the present invention can efficiently treat ammonia stripping solution so that ammonia can be completely treated, and after treating the digestion stripping liquid by methane fermentation in an anaerobic tank with an ammonia stripping process, the ammonia nitrogen and Its purpose is to remove nitrogen acetate.

Other objects of the present invention will be readily understood through the following description of the embodiments.

In order to achieve the above object, according to an aspect of the present invention, the organic wastewater treatment system having a high nitrogen content, methane fermentation tank for fermenting the organic wastewater; An anaerobic tank for removing ammonia from the digestion leachate discharged from the methane fermentation tank; Electrolyte removal unit for removing nitrogen components by electrolysis of the treatment liquid discharged from the anaerobic tank; And a gas purifying unit for purifying aeration gas generated from the anaerobic tank, wherein the organic wastewater treatment system having a high nitrogen content is provided.

The gas purification unit may further include a purified gas recycling supply unit supplying the purified gas to the anaerobic tank to be used as an aeration gas in the ammonia stripping process.

The electrolytic chlorine removing unit may use hypochlorous acid (HClO) to remove ammonia nitrogen and nitric acetate.

The gas purification unit may receive the digestion gas discharged from the methane fermentation tank together with the aeration gas discharged from the anaerobic tank to purify together.

The refinery gas recycling supply unit may further include a refinery gas supply line for supplying refinery gas to the anaerobic tank from a discharge line through which the refined gas purified from the gas purification unit is discharged; A refinery gas flow meter installed to measure a flow rate of the refinery gas in the refinery gas supply line; And a flow rate control valve installed in the refinery gas supply line to adjust the flow rate of the refinery gas, and the ammonia in the process solution by an ammonia concentration meter installed in a transfer line to supply the process solution from the anaerobic tank to the electrolytic deoxidation unit. Receives a detection value, receives a flow rate measurement of the refinery gas output from the refinery gas flow meter, and controls the amount of refinery gas supply to the anaerobic tank by controlling the flow control valve so that the ammonia detection value corresponds to a predetermined target value or a range of target values. The control unit may further include a.

According to the organic wastewater treatment system having a high nitrogen content according to the present invention, the wastewater having a high concentration of nitrogen such as animal wastewater and food waste wastewater is treated, and the digestive desorption liquid (fermented liquid) obtained in the methane fermentation treatment is used for the anaerobic activated sludge process. By reducing the amount of nitrogen in the methane fermentation solution, in particular, the concentration of ammonia nitrogen, the removal of nitrogen components such as ammonia nitrogen and nitrogen acetate can be efficiently and reliably treated by post-treatment electrolytic nitrogen removal.

1 is a block diagram showing a livestock wastewater treatment system according to the prior art,
2 is a block diagram showing an organic wastewater treatment system having a high nitrogen content according to an embodiment of the present invention,
3 is a block diagram showing an electrolyte deoxidation unit of an organic wastewater treatment system having a high nitrogen content according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but is to be understood to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention, And the scope of the present invention is not limited to the following examples.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant explanations thereof will be omitted.

2 is a block diagram showing an organic wastewater treatment system having a high nitrogen content according to an embodiment of the present invention.

As shown in FIG. 2, the organic wastewater treatment system 100 having a high nitrogen content according to an embodiment of the present invention includes a methane fermentation tank 110, an anaerobic tank 120, an electrolyte dechlorination unit 130, and a gas. It may include a purification unit 140.

The methane fermentation tank 110 to ferment the organic wastewater, the organic wastewater includes the organic waste. Livestock waste such as cattle and pigs, and organic waste such as food waste are separated or pulverized and slurried as necessary, and then introduced into the methane fermentation tank 110 using a pump or the like to start methane fermentation. The methane fermentation tank 110 is provided with a fixed block filled with immobilized microorganisms to which anaerobic microorganisms, such as methane, are attached. The methane fermentation of the slurry is performed, and organic waste is decomposed by anaerobic microorganisms.

The methane fermentation tank 110 may have a methane fermentation temperature of 50 to 60 ° C., but the fermentation by high temperature methane bacteria is performed by the methane fermentation temperature to further improve the decomposition rate of organic waste. In the interior, a stirring treatment device is installed, and stirring of the slurry which is an organic waste is performed. Here, the stirring method of the slurry may be a circulation of the slurry by the pump, and in addition, a part of the extinguishing gas may be blown to the lower portion of the methane fermentation tank 110 by the pump and stirred by bubbling. In addition, the methane fermentation tank 110 may be configured such that the slurry and the same amount of the digestion desorbent supplied every time are discharged from the methane fermentation tank 110 through a pipe, and the methane fermentation tank 110 is always filled with a certain amount of slurry. It may be.

Digestion and desorption liquid, which is the methane fermentation waste liquid discharged from the methane fermentation tank 110, is sent to the anaerobic tank 120 through a pipe, and the digestion gas generated by the methane fermentation removes harmful components such as ammonia nitrogen from the gas purification unit 140. In addition, the purified gas may be stored in a gas storage tank (not shown) through a pipe to be used as a fuel of a generator and a boiler such as a fuel cell generator and a gas engine.

The anaerobic tank 120 removes ammonia from the digestive leachate discharged from the methane fermentation tank 110.

The electrolytic deoxidation unit 130 removes nitrogen by electrolyzing the treatment liquid discharged from the anaerobic tank 120.

Gas purification unit 140 is to purify the aeration gas generated from the anaerobic tank 120, the aeration gas discharged from the anaerobic tank 120 with the digestion gas discharged from the methane fermentation tank 110 can be purified together. It is possible to use as long as it can remove harmful components such as ammonia nitrogen, and for example, an apparatus in which materials such as iron oxide and activated carbon are filled is suitable.

Organic wastewater treatment system 100 having a high nitrogen content according to an embodiment of the present invention is to supply the purified gas from the gas purification unit 140 to the anaerobic tank 120 to use as aeration gas in the ammonia stripping process It may further include a purified gas recycling supply unit 150 to.

The purified gas recycling supply unit 150 is a purified gas supply line for supplying purified gas to the anaerobic tank 120 from the discharge line 142 from which the purified gas purified by the blower 141 is discharged from the gas purification unit 140 ( 151, a refinery gas flow meter 152 which is installed in the refinery gas supply line 151 to measure the flow rate of refinery gas, and a flow rate control valve which is installed to regulate the flow rate of refinery gas in the refinery gas supply line 151 ( 153).

By the purified gas recycling supply unit 150, a part or all of the gas purified by the gas purification unit 140 is transferred to the anaerobic tank 120 through the refinery gas supply line 151 to process aeration with decomposition of organic matter. do. The ammonia in the digestion desorbent is accompanied by the digestion gas and is separated from the extinguishing detachment solution and introduced into the gas purification unit 140 together with the digestion gas directly derived from the methane fermentation tank 110 to remove the ammonia.

Ammonia concentration meter 132 for measuring the ammonia concentration for the anaerobic treated water may be installed in the transfer line 131 for transferring the treatment liquid, that is, anaerobic treated water from the anaerobic tank 120, to be supplied to the electrolytic denitrification unit 130. have. Therefore, the ammonia concentration meter 132 monitors the ammonia concentration in the anaerobic treated water to control the flow rate control valve 153 of the purified gas recycle supply unit 150, thereby adjusting the flow rate of the aeration gas by the purified gas flow meter 152. It becomes possible.

That is, the ammonia concentration meter 132 outputs the detected ammonia value in the anaerobic treated water, and compares the detected upper limit value with the target upper limit or the lower limit of the ammonia concentration in the anaerobic treated water to increase or decrease the flow rate of the aeration gas. Decide For example, when the detected value is larger than the upper limit of the target value, the flow rate control valve 153 is opened to increase the flow rate of the aeration gas. The aeration treatment by the aeration gas may be preferentially treated to reduce the ammonia concentration of the anaerobic treated water. On the other hand, when the detected value is smaller than the lower limit of the target value, the flow rate control valve 153 is tightened to reduce the flow rate of the aeration gas. The flow rate of the aeration gas is suppressed to the minimum necessary, the amount of digestion gas is increased, and can be effectively used as a gas utilization system such as power generation.

The target value for adjusting the flow rate of the aeration gas by the flow rate control valve 153, that is, the target value of the ammonia concentration in the anaerobic treated water is preferably 100 to 400 mgN / L. If the lower limit of the target value is less than 100 mgN / L, the effect of increasing the flow rate of the aeration gas is not suitable. In addition, such a target value does not necessarily need to have a fixed width between an upper limit value and a lower limit value, and may be one boundary value. It is preferable that the flow rate of the aeration gas supplied to the anaerobic tank 120 be 100 to 1,000 times by volume ratio with respect to the discharge 1 of the anaerobic treatment water.

The controller 160 may further include a controller 160 to automatically control the ammonia detection value measured by the ammonia concentration meter 132 to correspond to a target value or a range of the target value. Here, the control unit 160 receives the ammonia detection value in the treatment liquid by the ammonia concentration meter 132 installed in the transfer line 131 for the treatment liquid, that is, anaerobic treatment water is supplied to the electrolytic deoxidation unit 130 from the anaerobic tank 120. Receiving the flow rate measurement value of the refinery gas output from the refinery gas flow meter 152, and controlling the flow rate control valve 153 so that the ammonia detection value corresponds to a predetermined target value or a range of the target value, thereby supplying the refined gas supply amount to the anaerobic tank 20. Take control.

The electrolyte deoxidation unit 130 may discharge the processing liquid after the anaerobic treatment by the anaerobic tank 120, but since the predetermined amount of ammonia nitrogen component remains in the processing liquid, the electrolytic deoxidation unit 130 is an electrolysis device. To handle it perfectly. On the other hand, the anaerobic tank 120 can be used as long as the organic matter in the digestive lysate is decomposable by anaerobic bacteria.

The electrolyte chlorine removal unit 130 may use hypochlorous acid (HClO) to remove ammonia nitrogen and nitrate acetate, which will be described below with reference to the accompanying drawings.

As shown in FIG. 3, the electrolytic cell removing unit 130 includes an electrolytic cell 133 which accommodates the treatment liquid treated by the anaerobic tank 120 as the water to be treated, and an anode electrode 134 provided in the electrolytic cell 133. ) And a cathode electrode 135, and a power supply unit 136 for supplying power so that a current flows between the anode electrode 134 and the cathode electrode 135. Therefore, an electric current flows between the anode electrode 134 and the cathode electrode 135 to perform an electrolytic treatment on the water to be treated in the electrolytic cell 133.

In the electrolytic cell 133, a current flows between the anode electrode 134 and the cathode electrode 135 to generate a reaction as shown in Chemical Formulas 1 and 2 below.

First, chlorine ions contained in the water to be treated are oxidized on the anode side to form chlorine gas, as shown in the formula (1), and a part of the chlorine gas is hydrated as shown in formula (2) to form hypochlorous acid.

[Formula 1]

_{^{2Cl - ⇒ Cl 2 ↑ + 2e}} -

[Formula 2]

Cl ₂ + H ₂ O ⇒ HCl + HClO

In addition, ammonia in the water to be treated is reacted with hypochlorous acid as shown in the following Chemical Formula 3 to form nitrogen gas and is removed from the water to be treated.

(3)

2 / 3NH ₃ + HClO ⇒ 1 / 3N ₂ ↑ + HCl + H ₂ O

In addition, the ammonium ions in the water to be treated are reacted with hypochlorous acid as shown in Chemical Formula 4 below to be converted into nitrogen gas and removed from the water.

[Formula 4]

2NH ₄ ⁺ + 4HClO + 2e ^- ⇒ N ₂ ↑ + 4HCl + 4H ₂ O

The electrolyte deoxidation unit 130 is preferably provided with a mechanism for adding a substance for supplying chlorine ions to the treated water, that is, sodium chloride (NaCl) when the concentration of chlorine ion in the treated water is low. In addition, when acetic acid ions are included in the water to be introduced into the electrolytic cell 133, the acetic acid ions are reduced to ammonia as shown in the following Chemical Formulas 5 and 6 via the acetic acid ion on the cathode surface.

[Chemical Formula 5]

^{_{NO 3 - + H 2 O +}} 2e - ⇒ NO 2 - + 2OH -

[Formula 6]

^{_{NO 2 - + 5H 2 O +}} 6e - ⇒ NH 3 + 7OH -

The ammonia produced by the formula (6) is removed from the water to be treated by the formula (3) by reacting with the hypochlorous acid produced by the formula (2).

A series of reactions of Chemical Formula 1 to Chemical Formula 6 are continuously generated in the electrolyzer 133 to completely remove ammonia nitrogen, nitrogen acetate, and nitrogen acetate from the treated water.

As described above, according to the present invention, the organic waste is introduced into the methane fermentation tank 110 to be methane fermented by anaerobic microorganisms and discharged into the digestive gas and the extinguishing liquid. After the gas purification process of removing impurities such as ammonia from the digested gas generated in the methane fermentation tank 110 to make a purified gas, the anaerobic tank 120 is aerated using some or all of the purified gas as an aeration gas. The gas after the aeration treatment is further processed by the gas purification unit 140. Then, the concentration of ammonia in the extinguishing solution or the amount of ammonia in the treated water after the aeration treatment is measured, and the supply amount of the aeration gas is controlled in accordance with this measurement value, so that the concentration of ammonia can be kept below a predetermined value.

In addition, since the supply amount of the aeration gas can be controlled according to the measurement value of the ammonia concentration, the optimum amount of the aeration gas can be supplied, and the extinguishing gas can be efficiently used. In addition, since the gas after the aeration treatment can be processed once again in the gas purification unit 140, it is possible to simply configure the device without the need for a catalytic combustion device such as an ammonia stripping process.

Since the digestion gas after the purification process of the gas purification unit 140 is used as the aeration gas, impurities such as ammonia are removed from the aeration gas. This makes it possible to further increase the ammonia removal efficiency from the digestive sorbent.

In addition, it is suitable to introduce the digestive desorption liquid and the aeration gas discharged from the methane fermentation tank 110 into the anaerobic tank 120 to decompose the organic matter in the digestive desorption liquid in the anaerobic tank 120 and simultaneously perform aeration treatment. In this way, since the decomposition and aeration of organic matter can be simultaneously performed in the anaerobic tank 120, it is not necessary to separately install the anaerobic tank and the aeration tank as in the conventional microbial treatment process, and ammonia is more convenient than the conventional microbial treatment process. Can be processed. Meanwhile, ammonia nitrogen and nitric acid acetate, which are not removed in the ammonia sheeting process of the anaerobic tank 10, remain in the treatment liquid that is processed in the anaerobic tank 120 and then transferred to the electrolytic deoxidation unit 130. Such ammonia nitrogen and acetic acid nitrogen are reliably treated by electrolysis in the electrolyte denitrification unit 130.

Although the present invention has been described with reference to the accompanying drawings, it is to be understood that various changes and modifications may be made without departing from the spirit of the invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the following claims.

110: methane fermentation tank 120: anaerobic tank
130: electrolyte deoxidation unit 131: transfer line
132: ammonia concentration meter 133: electrolytic cell
134: anode electrode 135: cathode electrode
136: power supply 137: drain line
138: on-off valve 140: gas purification unit
141: blower 142: discharge line
150: purified gas recycling supply unit 151: purified gas supply line
152: refined gas flow meter 153: flow control valve
160:

Claims (5)

In organic wastewater treatment system with high nitrogen content,
Methane fermentation tank for fermenting organic wastewater;
An anaerobic tank for removing ammonia from the digestion leachate discharged from the methane fermentation tank;
Electrolyte removal unit for removing nitrogen components by electrolysis of the treatment liquid discharged from the anaerobic tank; And
Organic wastewater treatment system having a high nitrogen content, characterized in that it comprises a gas purification unit for purifying the aeration gas generated from the anaerobic tank. The organic gas of claim 1, further comprising a purified gas recycling supply unit configured to supply the purified gas purified by the gas purification unit to the anaerobic tank to be used as an aeration gas in an ammonia stripping process. Wastewater treatment system. The method of claim 1, wherein the electrolyte deoxidation unit,
An organic wastewater treatment system having a high nitrogen content, characterized in that hypochlorous acid (HClO) is used to remove ammonia nitrogen and acetic acid nitrogen. The gas purifying unit according to claim 1 or 2,
The organic wastewater treatment system having a high nitrogen content, characterized in that the digestion gas discharged from the methane fermentation tank is supplied with the aeration gas discharged from the anaerobic tank. The method of claim 2, wherein the purified gas recycling supply unit,
A refinery gas supply line for supplying refinery gas to the anaerobic tank from a discharge line through which the refined gas purified from the gas purification unit is discharged;
A refinery gas flow meter installed to measure a flow rate of the refinery gas in the refinery gas supply line; And
It includes a flow control valve installed to adjust the flow rate of the purified gas in the purified gas supply line,
Receive the detection value of ammonia in the treatment liquid, the flow rate measurement of the purified gas output from the purified gas flow meter by the ammonia concentration meter installed in the transfer line for supplying the treatment liquid from the anaerobic tank to the electrolyte deoxidation unit, the ammonia And a control unit for controlling the amount of purified gas supplied to the anaerobic tank by controlling the flow regulating valve so that the detected value corresponds to a predetermined target value or a range of the target value.

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