KR100992463B1 - Apparatus and method for waste-water treatment with phosphorous filtering tank and submerged membrane module - Google Patents

Abstract

The present invention improves the efficiency of denitrification and dephosphorization by maintaining the concentration of organic matter in the wastewater at a constant level, and improves the membrane separation device of the MBR tank to reduce maintenance costs. And a method for treating wastewater using a phosphorus filtration tank and a membrane separation device according to the present invention include a total denitrification tank for denitrifying nitrite nitrogen and nitrate nitrogen contained in the wastewater and the return sludge, and the inflow water from the total denitrification tank. An anaerobic tank receiving phosphorus and releasing phosphorus contained in the influent, a phosphorus filtering tank provided at the end of the anaerobic tank to recover phosphorus discharged from the anaerobic tank, and a first intermittent aeration tank provided sequentially at the rear end of the phosphorus filtering tank; It consists of two intermittent aeration tank, the filter medium is filled in the phosphorus filtration tank Said, the filter medium is characterized in that the number of adsorption released from the anaerobic tank.

Description

Apparatus and method for waste-water treatment with phosphorous filtering tank and submerged membrane module

The present invention relates to a wastewater treatment apparatus and method using a phosphorus filtration tank and a membrane separation device, and more particularly, to maintain the concentration of organic matter in the wastewater at a constant level, to double the efficiency of denitrification and dephosphorization, and to provide a membrane separation apparatus of an MBR tank. The present invention relates to a wastewater treatment apparatus and method using a phosphorus filtration tank and a membrane separation apparatus that can reduce maintenance costs by improving.

At present, the most widely used wastewater advanced treatment process is an A2O process consisting of an anaerobic tank, an anoxic tank, and a membrane separation tank, and many modification processes are applied. The biggest limiting factor of the A2O process is that the removal efficiency of nitrogen and phosphorus is lowered when the concentration of organic matter contained in the sewage is lower than that of nitrogen and phosphorus. In order to solve this problem, various types of modified advanced treatment processes have been developed, but they cannot fundamentally solve the problem of denitrification and dephosphorization efficiency due to the lack of organic matter.

For example, the method of increasing the concentration of organic matter in the influent by adding manure or food waste leachate, etc. has another problem in the wastewater itself, rather it causes problems in the whole high-treatment process. The most common way to solve this problem is to supply the organic deficiency to methanol, etc. when denitrification or to give up the biological removal part such as MLE (Modified Ludjack Ettinger) method and to set up the process for nitrogen removal only. Phosphorus is agglomerated and removed and discharged.

Meanwhile, as the expectation for the advanced treatment process increases and the demand for reuse of the treated water increases, MBR (Membrane bio-reactor) method for replacing the sedimentation tank with a membrane separator has been developed and used. The MBR method has a small installation area, easy to operate automatically, and does not require a separate settling tank to solve problems such as sludge bulking. In addition, the amount of excess sludge generated is much smaller than the conventional method. However, the MBR process is not easy to maintain the membrane separator. Frequent membrane cleaning is necessary to eliminate membrane blockage, which shortens membrane life and increases maintenance costs. Therefore, in the MBR method, it is important that the membrane separator be combined with a high performance process, which is excellent in performance, but the smooth operation and membrane life of the membrane separator are also important.

The present invention has been made to solve the above problems, by maintaining the concentration of organic matter in the sewage water to a certain level to increase the efficiency of denitrification, dephosphorization and improve the membrane separation device of the MBR tank to lower the maintenance cost It is an object of the present invention to provide a wastewater treatment apparatus and method using a phosphorus filtration tank and a membrane separation device.

The wastewater treatment apparatus using the phosphorus filtration tank and the membrane separation apparatus according to the present invention for achieving the above object is a total denitrification tank for denitrifying nitrite and nitrate nitrogen contained in the wastewater and the return sludge, and from the total denitrification tank An anaerobic tank receiving influent and releasing phosphorus contained in the influent, a phosphorus filtering tank provided at the end of the anaerobic tank to recover phosphorus discharged from the anaerobic tank, and a first intermittent aeration tank sequentially provided at a rear end of the phosphorus filtering tank; And a second intermittent aeration tank, wherein <phosphoride discharged sludge> and <phosphate accumulated effluent> in the anaerobic tank are supplied to the phosphorus filtration tank, and the media for adsorbing and recovering phosphorus in the phosphorus filtration tank is provided. It is characterized by.

In addition, the wastewater treatment apparatus using the phosphorus filtration tank and the membrane separation device according to the present invention is a total denitrification tank for denitrifying nitrite nitrogen and nitrate nitrogen contained in the wastewater and the return sludge, and the influent water is supplied from the total denitrification tank An anaerobic tank for discharging phosphorus contained therein, a phosphorus filtering tank provided at the end of the anaerobic tank for recovering phosphorus released from the anaerobic tank, and a first intermittent aeration tank and a second intermittent aeration tank sequentially provided at the rear ends of the phosphorus filtering tank; Raw water in the anaerobic tank is separated into <sludge discharged phosphorus> and <supernatant accumulated phosphorus> by the solid-liquid separation process, <slurry discharged phosphorus> under the anaerobic tank is the first intermittent aeration tank <Supernatant accumulated phosphorus> in the upper anaerobic tank is supplied to the phosphorus filtering tank, the phosphorus is adsorbed, ash in the phosphorus filtering tank And that the filter material to be provided with other features.

The filter medium in the phosphorus filtration tank may be composed of ocher filter media.

Each of the first intermittent aeration tank and the second intermittent aeration tank is alternately operated in abandonment and aeration states, and the operating states of the first intermittent aeration tank and the second intermittent aeration tank are opposite to each other. In addition, the second intermittent aeration tank is further provided with an immersion type membrane separation device, the immersion type membrane separation device may be configured to include a flat membrane or hollow fiber membrane filtration membrane, and a nonwoven fabric provided on the outer surface of the filtration membrane. have.

The immersion type membrane separation device operates only in the abandoned state of the second intermittent aeration tank to produce treated water, and sludge in the second intermittent aeration tank is returned to the total denitrification tank, and the conveyance of the sludge is carried out in the second intermittent aeration tank. Only in abandonment state.

The first intermittent aeration tank and the second intermittent aeration tank convert organic nitrogen and ammonia nitrogen to nitrite and nitrate nitrogen in aeration state, and reduce nitrite and nitrate nitrogen to nitrogen gas in an aeration state. Meanwhile, a membrane separation tank may be further provided at a rear end of the second intermittent aeration tank, and an immersion type membrane separation device may be provided in the membrane separation tank.

In the wastewater treatment method using a phosphorus filtration tank and a membrane separation device according to the present invention, in the wastewater treatment method using a wastewater treatment apparatus in which a total denitrification tank, an anaerobic tank, a phosphorus filtration tank, a first intermittent aeration tank, and a second intermittent aeration tank are sequentially disposed, In the state where the wastewater and the return sludge are supplied to the total denitrification tank, the denitrification process of nitrite nitrogen and nitrate nitrogen proceeds, and the inflow water is supplied from the total denitrification tank to the anaerobic tank, and the phosphorus in the inflow water is discharged. And supplying <phosphorus discharged sludge> and <phosphate accumulated effluent> in the anaerobic tank to the phosphorus filtration tank, and the first intermittent aeration tank and the second intermittent aeration tank are alternately operated in aeration state and aeration state. In the abandoned state, organic nitrogen and ammonia nitrogen are converted to nitrous and nitrate nitrogen, and in aerobic state, nitrous and nitrate nitrogen are nitrogen gas. It characterized in that comprises a step of reduction.

In addition, the wastewater treatment method using a phosphorus filtration tank and a membrane separation device according to the present invention is a wastewater treatment method using a wastewater treatment apparatus in which a total denitrification tank, an anaerobic tank, a phosphorus filtration tank, a first intermittent aeration tank, and a second intermittent aeration tank are sequentially disposed. In the state, the wastewater and the return sludge is supplied to the total denitrification tank, the denitrification process of nitrite nitrogen and nitrate nitrogen is in progress, the inflow water is supplied from the total denitrification tank to the anaerobic tank, the phosphorus in the inlet water is discharged And the sludge discharged from the phosphorus by the solid-liquid separation in the anaerobic tank and <supernatant accumulated phosphorus>, the sludge discharged from the lower anaerobic tank is supplied to the first intermittent aeration tank, The supernatant in which the upper phosphorus accumulates is supplied to the phosphorus filtration tank and the first intermittent aeration tank and the second intermittent aeration tank are alternated in aeration state and aeration state. Before and giving the state when and the organic nitrogen and ammonia nitrogen converted to nitrite and nitrate nitrogen, and the non-giving condition nitrite and nitrate is made by a step that is reduced to nitrogen gas by different features.

The second intermittent aeration tank is further provided with an immersion type membrane separation device, and when the second intermittent aeration tank is abandoned, the treated water production process by the immersion type membrane separation device may be performed. In addition, the sludge in the second intermittent aeration tank may be conveyed to the total denitrification tank when the second intermittent aeration tank is abandoned.

The wastewater treatment apparatus and method using a phosphorus filtration tank and a membrane separation apparatus according to the present invention have the following effects.

A total denitrification tank is placed in front of the anaerobic tank to remove residual dissolved oxygen in the conveying sludge and reduce nitrate nitrogen to nitrogen gas, thereby eliminating organic competition between denitrifying microorganisms and phosphorus storage microorganisms that may occur in the anaerobic tank. Enables smooth phosphorus release.

In addition, as a phosphorus filtration tank for adsorbing and recovering the phosphorus released in the rear stage of the anaerobic tank is provided, the remaining phosphorus is recovered and the phosphorus starvation microorganisms are excessively ingested in the aeration process of the second stage intermittent aeration tank. This can remove most of the phosphorus in the influent. In addition, as phosphorus is adsorbed and recovered in the phosphorus filtration tank, the organic matter shortage phenomenon can be eliminated even in the treatment of wastewater having a low C / N ratio, thereby enabling high-efficiency nitrogen removal.

In addition, while maintaining the advantages of the existing MBR, by providing a nonwoven fabric on the outer surface of the filtration membrane can solve the fouling problem, maintain a constant flow rate and reduce the maintenance cost.

1 is a block diagram of a wastewater treatment apparatus using a phosphorus filtration tank and a membrane separation device according to an embodiment of the present invention.
2 is a block diagram of a wastewater treatment apparatus using a phosphorus filtration tank and a membrane separation device according to another embodiment of the present invention.

Hereinafter, a wastewater treatment apparatus and method using a phosphorus filtration tank and a membrane separation apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

As shown in Figure 1, the wastewater treatment apparatus using a phosphorus filtration tank and a membrane separation apparatus according to an embodiment of the present invention is largely denitrification tank 10, anaerobic tank 20, the first intermittent aeration tank 40 and the first It consists of a combination of 2 intermittent aeration tanks 50.

The total denitrification tank 10 serves to denitrate nitrite nitrogen and nitrate nitrogen contained in the sludge conveyed from the sewage waste water and the second intermittent aeration tank 50. The total denitrification tank 10 is provided with a stirrer for stirring the wastewater and the return sludge, and the residence time of the wastewater and the return sludge in the total denitrification tank 10 is preferably about 30 minutes in order to reduce dissolved oxygen. . On the other hand, the reason why the pre-denitrification tank 10 is provided in this way is to denitrify and dephosphorus to proceed in order to block the competition of organic matters commonly generated in the simultaneous removal process of nitrogen and phosphorus.

The anaerobic tank 20 serves to release phosphorus contained in the inflow water flowing from the total denitrification tank 10. Specifically, the polymerized phosphate in the process of organic matter in the influent is converted to VFAs (volatile fatty acid) under the anaerobic condition and stored as PHB (Poly-β-Hydroxyl Butyrate) in the cells of phosphorous storage micro-organism (Ancinetobactor) (polyphosphate) is converted into orthophosphate and released. In this process, organic matter in the anaerobic tank 20 is reduced and PO ₄ -P is increased. Phosphorus release in the anaerobic tank 20 is preferably performed for about 1 hour 30 minutes.

Raw water from which the phosphorus discharge is completed in the anaerobic tank 20 is discharged to the first intermittent aeration tank 40, and may be discharged to the first intermittent aeration tank 40 through the following two paths. The first route is Sludge (relatively small phosphorus concentration) precipitated by solid-liquid separation in the state in which the phosphorus discharge from the anaerobic tank 20 is completed, flows out into the first intermittent aeration tank 40, and the supernatant liquid containing a large amount of phosphorus released is It flows out to the phosphorus filtration tank 30 provided in the end of the anaerobic tank 20. At this time, the solid-liquid separation in the anaerobic tank 20 may be implemented through the batch design of the anaerobic tank 20 and the phosphorus filtration tank 30 or through a fixed time fixed. In the case of the former solid-liquid separation, specifically, the lower surface of the phosphorus filtration tank 30 is provided at a position spaced from the lower surface of the anaerobic tank 20 by a predetermined distance so that the lower space of the phosphorus filtration tank 30 is minimized from the influence of the stirrer. Solid-liquid separation can be implemented. On the other hand, the raw water introduced into the phosphorus filtration tank 30 is finally discharged to the first intermittent aeration tank 40 after the self-treatment process, will be described later in the self-treatment process of the phosphorus filtration tank 30.

The second path is supplied to the phosphorus filtration tank 30 immediately after the phosphorus discharge process is completed without solid-liquid separation in the anaerobic tank 20, followed by the treatment process in the phosphorus filtration tank 30. 1 is an outflow path to the intermittent aeration tank 40. In the second route, the phosphorus discharged sludge and the phosphorus effluent are fed together to the phosphorus filtration tank 30.

As described above, a phosphorus filtration tank 30 is provided at the end of the anaerobic tank 20. The phosphorus filtration tank 30 serves to recover phosphorus discharged from the anaerobic tank 20 and ultimately prevent the organic matter concentration from being lowered when treating wastewater having a low carbon / nitrogen (C / N) ratio. Specifically, the supernatant of the upper part of the anaerobic tank 20 separated by solid-liquid separation of the anaerobic tank 20, that is, the supernatant of the upper part of the anaerobic tank 20 containing a large amount of phosphorus flows into the phosphorus filtering tank 30, and the phosphorus filtering tank Phosphorus is adsorbed and recovered by the loess filter material 31 filled in the (30). At this time, when the effluent is supplied from the anaerobic tank 20 to the phosphorus filtration tank 30 through the second path as described above, the phosphorus filtration tank 30 targets the sludge discharged phosphorus and the effluent containing phosphorus Proceed with phosphorus recovery. For reference, the residence time of the supernatant in the phosphorus filtration tank 30 is preferably about 0.1 hours, the outflow of the phosphorus filtration tank 30 is introduced into the first intermittent aeration tank (40).

The first intermittent aeration tank 40 and the second intermittent aeration tank 50 are alternately driven and aerated, and the first intermittent aeration tank 40 and the second intermittent aeration tank 50 are operated in opposite states to each other. . That is, when the first intermittent aeration tank 40 is abandoned, the second intermittent aeration tank 50 proceeds with stirring only in a non-aerated state, on the contrary, when the first intermittent aeration tank 40 proceeds with agitation only the second intermittent state. The aeration tank 50 is operated in the aeration state in which air is introduced. The residence time of the first and second intermittent aeration tanks 40 and 50 may vary somewhat depending on the characteristics of the influent, but each of the wastewater is operated within a range of 2 hours when the inflow concentration of the wastewater is 200 mg / l based on BOD. If the inlet concentration is increased, it can be operated within the range of 3 hours. In addition, the aeration and aeration times are also operated for 30 minutes at 200mg / l BOD basis, can be operated for 45 minutes depending on the concentration of organic matter and nitrogen in the sewage. For reference, the first intermittent aeration tank 40 and the second intermittent aeration tank 50 is provided with an diffuser 70 for selectively supplying oxygen and a stirrer.

On the other hand, looking at the role of the first intermittent aeration tank 40 and the second intermittent aeration tank 50, first the first intermittent aeration tank 40 is organic nitrogen and ammonia nitrogen in aeration state to nitrite and nitrate nitrogen Switch. At this time, the phosphorus in the inflow water flowing into the first intermittent aeration tank 40 is mostly ingested by the phosphorus storage microorganisms in the phosphorus starvation state. When the first intermittent aeration tank 40 is in the abandoned state, the second intermittent aeration tank 50 is in the form of an anaerobic tank as a non-aerator, and the nitrate nitrogen introduced from the first intermittent aeration tank 40 is reduced to nitrogen gas. At this time, the remaining organic matter is consumed in the reduction process of the nitrate nitrogen.

When the aeration state of the first intermittent aeration tank 40 is switched to the non-aeration state, the oxidized nitrogen nitrate is denitrated in the aeration state, and the second intermittent aeration tank 50 is switched from the aeration state to the aeration state to obtain phosphorus. Remove by ingestion.

On the other hand, the second intermittent aeration tank 50 is provided with an immersion type membrane separation device (60). The immersion type membrane separation device 60 serves to produce treated water by filtering raw water in the second intermittent aeration tank 50. The immersion membrane separation device 60 is formed of a flat membrane or hollow fiber membrane filtration membrane (fine filtration membrane or ultrafiltration membrane), and serves to reduce membrane differential pressure and reduce membrane differential pressure on the outer surface of the filtration membrane. A nonwoven fabric is provided. At this time, the immersion type membrane separation device 60 is operated only during the aeration operation of the second intermittent aeration tank 50. In addition, sludge in the second intermittent aeration tank 50 is conveyed to the total denitrification tank 10. As described above, the diffuser 70 is provided in the first and second intermittent aeration tanks 40 and 50. In the second intermittent aeration tank 50, the diffuser 70 is the immersion membrane. It is preferably provided at the bottom of the separator 60, to prevent sludge deposited on the surface of the filtration membrane.

The submerged membrane separation device 60 may be provided in a separate membrane separation tank 80 in addition to being provided in the second intermittent aeration tank 50. In this case, as shown in Figure 2, the total denitrification tank 10, anaerobic tank 20, phosphorus filtration tank 30, the first intermittent aeration tank 40, the second intermittent aeration tank 50, immersion type membrane separation device It consists of a combination of the membrane separation tank 80 provided with (60).

Above, the configuration of the wastewater treatment apparatus using the phosphorus filtration tank 30 and the membrane separation device 60 according to an embodiment of the present invention has been described. In the present invention, as the total denitrification tank 10 is provided at the front of the anaerobic tank 20, the dissolved oxygen in the conveying sludge is removed and the dephosphorization process takes place actively, and the released high concentration of phosphorus is recovered in the phosphorus filtration tank 30. By going through the process of denitrification and dephosphorization proceeds in sequence it becomes possible to efficiently distribute the organic matter during denitrification and dephosphorization process. In addition, by using the immersion type membrane separation device 60 provided with a nonwoven fabric on the outer surface of the filtration membrane, it is possible to prevent maintenance of membrane differential pressure caused by the high concentration MLSS to extend the membrane replacement time and increase the cleaning cycle to reduce maintenance costs It becomes possible.

Next, the treatment efficiency of the wastewater treatment apparatus equipped with a phosphorus filtration tank and a membrane separation apparatus according to an embodiment of the present invention will be described. Table 1 below shows the treatment efficiency of the wastewater treatment apparatus according to the embodiment of the present invention.

Treatment efficiency of sewage treatment system according to an embodiment of the present invention Raw water concentration (mg / L) Treated water concentration (mg / L) Treatment efficiency (%) BOD 223.1 4.9 97.8 COD _cr 312.3 8.3 97.3 SS 117.2 0.2 99.8 T-N 41.7 3.1 92.6 T-P 5.1 0.2 94.2

Referring to <Table 1>, the average BOD concentration of the influent was 223.1mg / L, the treated water was 4.9mg / L, which showed 97.8% removal efficiency, and for COD _cr , the treated water concentration was 8.3mg / L. The removal efficiency was 97.3%. Sustained material (SS) through the nominal pore 0.4㎛ flat membrane (MF) was a complete solid-liquid separation to ensure clean water quality. Total nitrogen (TN) was introduced at an average of 41.7 mg / L and discharged at 3.1 mg / L, with an average removal efficiency of 92.6%. In addition, total phosphorus (TP) introduced at 5.1 mg / L was treated with an average of 0.2 mg / L, resulting in a removal efficiency of 94.2%.

10: total denitrification tank 20: anaerobic tank
30: phosphorus filtration tank 31: filter medium
40: first intermittent aeration tank 50: second intermittent aeration tank
60: submerged membrane separator 70: diffuser
80 membrane separation tank

Claims (14)

A total denitrification tank for denitrifying nitrite nitrogen and nitrate nitrogen contained in the wastewater and the return sludge;
An anaerobic tank receiving influent from the total denitrification tank and releasing phosphorus contained in the influent;
A phosphorus filtration tank provided at the end of the anaerobic tank to recover phosphorus discharged from the anaerobic tank; And
It comprises a first intermittent aeration tank and a second intermittent aeration tank sequentially provided at the rear end of the phosphorus filtration tank,
The second intermittent aeration tank is further provided with an immersion type membrane separation device,
<Phosphorus discharged sludge> and <phosphate accumulated phosphate> in the anaerobic tank is supplied to the phosphorus filtration tank, phosphorus filtration tank and membrane separation device, characterized in that the filter medium is provided with the adsorption, recovery Wastewater treatment device using the.
A total denitrification tank for denitrifying nitrite nitrogen and nitrate nitrogen contained in the wastewater and the return sludge;
An anaerobic tank receiving influent from the total denitrification tank and releasing phosphorus contained in the influent;
A phosphorus filtration tank provided at the end of the anaerobic tank to recover phosphorus discharged from the anaerobic tank; And
It comprises a first intermittent aeration tank and a second intermittent aeration tank sequentially provided at the rear end of the phosphorus filtration tank,
The second intermittent aeration tank is further provided with an immersion type membrane separation device,
Raw water in the anaerobic tank is separated into <sludge discharged phosphorus> and <supernatant accumulated phosphorus> by the solid-liquid separation process,
<Sludge which discharged phosphorus in the lower part of the anaerobic tank is supplied to the first intermittent aeration tank, <Supernatant accumulated phosphorus in the upper part of the anaerobic tank is supplied to the phosphorus filtration tank,
The wastewater treatment apparatus using a phosphorus filtration tank and a membrane separation device, characterized in that the filter medium for adsorbing and recovering phosphorus is provided in the phosphorus filtration tank.
The wastewater treatment apparatus using a phosphorus filtration tank and a membrane separation device according to claim 1 or 2, wherein the media in the phosphorus filtration tank is composed of ocher media.
The method of claim 1 or 2, wherein the first intermittent aeration tank and the second intermittent aeration tank are alternately operated in abandonment and aeration states, the operating state of the first intermittent aeration tank and the second intermittent aeration tank is opposite to each other. Wastewater treatment apparatus using a phosphorus filtration tank and a membrane separation device.
delete The method of claim 1 or 2, wherein the immersion membrane separator,
A wastewater treatment apparatus using a phosphorus filtration tank and a membrane separation device, comprising a filtration membrane of a flat membrane type or a hollow fiber membrane type, and a nonwoven fabric provided on an outer surface of the filtration membrane.
The wastewater treatment apparatus according to claim 1 or 2, wherein the immersion type membrane separation apparatus operates only in the abandoned state of the second intermittent aeration tank to produce treated water.
3. The phosphorus filtration tank and the membrane separation according to claim 1 or 2, wherein the sludge in the second intermittent aeration tank is returned to the total denitrification tank, and the sludge is returned only in the abandoned state of the second intermittent aeration tank. Wastewater treatment system using the device.
5. The method according to claim 4, wherein the first intermittent aeration tank and the second intermittent aeration tank convert organic nitrogen and ammonia nitrogen into nitrite and nitrate nitrogen in aeration state, and in the aeration state, nitrogen and nitrate nitrogen are converted into nitrogen. Wastewater treatment apparatus using a phosphorus filtration tank and a membrane separation device, characterized in that the reduction to gas.
delete In the wastewater treatment method using the sewage treatment system in which the total denitrification tank, anaerobic tank, phosphorus filtration tank, the first intermittent aeration tank, and the second intermittent aeration tank are sequentially arranged,
Denitrification of nitrite nitrogen and nitrate nitrogen in a state in which wastewater and return sludge are supplied to the total denitrification tank;
Inflow water is supplied from the total denitrification tank to the anaerobic tank, and phosphorus in the inflow water is discharged;
Supplying <phosphorus released sludge> and <phosphate accumulated effluent> in the anaerobic tank to the phosphorus filtration tank; And
The first intermittent aeration tank and the second intermittent aeration tank are alternately operated in aeration state and aeration state, and in the abandonation state, organic nitrogen and ammonia nitrogen are converted into nitrous acid and nitrate nitrogen, and in the aeration state, nitrite and vaginal Acidic nitrogen is reduced to nitrogen gas,
An immersion type membrane separation device is further provided in the second intermittent aeration tank, and when the second intermittent aeration tank is abandoned, a process for producing treated water by the immersion type membrane separation device is performed. Wastewater treatment method using the.
In the wastewater treatment method using the sewage treatment system in which the total denitrification tank, anaerobic tank, phosphorus filtration tank, the first intermittent aeration tank, and the second intermittent aeration tank are sequentially arranged,
Denitrification of nitrite nitrogen and nitrate nitrogen in a state in which wastewater and return sludge are supplied to the total denitrification tank;
Inflow water is supplied from the total denitrification tank to the anaerobic tank, and phosphorus in the inflow water is discharged;
In the anaerobic tank, <liquid discharged from sludge> and <supernatant accumulated phosphorus> are separated by solid-liquid separation, and the sludge discharged from the lower anaerobic tank is supplied to the first intermittent aeration tank, and the phosphorus at the top of the anaerobic tank is The accumulated supernatant is supplied to the phosphorus filtration tank; And
The first intermittent aeration tank and the second intermittent aeration tank are alternately operated in aeration state and aeration state, and in the abandonation state, organic nitrogen and ammonia nitrogen are converted into nitrous acid and nitrate nitrogen, and in the aeration state, nitrite and vaginal Acidic nitrogen is reduced to nitrogen gas,
An immersion type membrane separation device is further provided in the second intermittent aeration tank, and when the second intermittent aeration tank is abandoned, a process for producing treated water by the immersion type membrane separation device is performed. Wastewater treatment method using the.
delete 13. The wastewater treatment method according to claim 11 or 12, wherein the sludge in the second intermittent aeration tank is returned to the total denitrification tank when the second intermittent aeration tank is abandoned.

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