Aquaculture integrated anaerobic ammonia oxidation denitrification device and process thereof

Abstract

The invention discloses an aquaculture integrated anaerobic ammonia oxidation denitrification device and a process thereof, and relates to the technical field of sewage treatment.The aquaculture integrated anaerobic ammonia oxidation denitrification device comprises a tank body, an exhaust port is formed in the top of the tank body, a drain outlet is formed in the bottom of the tank body, and a water outlet and a water inlet are formed in the side wall of the tank body; the interior of the tank body is divided into a clear water area, a PD / A reaction area, an anaerobic reaction area, a vertical flow precipitation area and a sewage collection area from top to bottom, and water quality detection ports are formed in the side walls, located in the anaerobic reaction area and the PD / A reaction area, of the tank body. Breeding tail water enters the tank body from the vertical flow sedimentation area and passes through the anaerobic reaction area and the PD / A reaction area, clear water enters the clear water area to be discharged, and sludge enters the sewage collection area to be discharged. And the defect that the traditional nitrification and denitrification nitrogen removal reaction process is not suitable for large-flow and low-nitrogen pollution load aquaculture water treatment is overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to an integrated anaerobic ammonia oxidation denitrification device for aquaculture and a process thereof. Background Art

[0002] Aquaculture tailwater has the characteristics of high COD, high DO concentration, coexistence of three forms of nitrogen, and low carbon-nitrogen ratio (C / N), low ammonia nitrogen and nitrite concentrations, resulting in low denitrification efficiency of traditional nitrification and denitrification reaction processes; and traditional nitrification and denitrification process facilities occupy a large area, have a large aeration volume, consume a lot of carbon sources, and have high energy consumption and cost, which are not suitable for aquaculture water quality treatment with large flow and low nitrogen pollution load. At present, research in the field of aquaculture water treatment is mainly limited to converting ammonia nitrogen and nitrite, which are directly harmful to fish, into nitrate nitrogen, which has no obvious harm to aquatic animals, and has not fundamentally removed the nitrogen pollution load from the aquaculture system. The continuous accumulation of nitrate nitrogen in the system, on the one hand, will cause environmental stress to aquaculture animals and affect their growth when it reaches a certain threshold; on the other hand, it will be reversely converted into nitrite nitrogen and ammonia nitrogen under certain conditions, directly endangering aquaculture animals. There is an urgent need for a new denitrification device suitable for aquaculture water treatment, low consumption and high efficiency.

[0003] Therefore, an anaerobic ammonium oxidation water treatment device is needed. Summary of the invention

[0004] In view of the above shortcomings, the present invention provides an integrated anaerobic ammonia oxidation denitrification device and process for aquaculture, which can overcome the defect that the traditional nitrification and denitrification reaction processes are not suitable for aquaculture water treatment with large flow and low nitrogen pollution load. The specific technical scheme is as follows:

[0005] An anaerobic ammonia oxidation water treatment device comprises a tank body, wherein the top of the tank body is provided with an exhaust port, the bottom of the tank body is provided with a sewage outlet, the side walls of the tank body are provided with a water outlet and a water inlet, respectively, the interior of the tank body is divided into a clean water area, a PD / A reaction area, an anaerobic reaction area, a vertical flow sedimentation area and a sewage collection area from top to bottom, and the side walls of the tank body located in the anaerobic reaction area and the PD / A reaction area are provided with water quality detection ports.

[0006] Preferably, the clean water zone includes a first bracket net and filter cotton, the first bracket net is installed on the inner wall of the tank body and is perpendicular to the axis of the tank body, the filter cotton is installed on the first bracket net and is used to filter the tail water after treatment in the PD / A reaction zone, and the water outlet is located above the filter cotton.

[0007] Preferably, the PD / A reaction zone includes a second bracket net, an inner tube bracket, an inner tube, a guide net, an inner tube guide plate and an air distribution pipe, the second bracket net is installed on the inner wall of the tank body and is perpendicular to the axis of the tank body, one end of the guide net is installed on the second bracket net, the inner tube bracket is installed on the inner wall of the tank body and is perpendicular to the axis of the tank body, the inner tube bracket is located between the second bracket net and the clean water area, the air distribution pipe is installed on the side of the second bracket net away from the guide net, the inner tube is installed on the inner tube bracket, the inner tube guide plate is installed at one end of the inner tube close to the guide net, and the inner tube and the guide net are coaxial with the tank body.

[0008] Preferably, the guide net is trumpet-shaped and opens upward, the end of the guide net away from the second bracket net is connected to the inner wall of the tank body, the inner tube guide plate is trumpet-shaped and opens downward, and the end of the guide net close to the second bracket net is not provided with a filter hole.

[0009] Preferably, the air distribution pipe is spirally arranged on the second bracket net for 2-3 circles, and the gas introduced by the air distribution pipe is air.

[0010] Preferably, the vertical flow sedimentation area includes a vertical flow sedimentator, a third bracket net, a water inlet reflector and a water distribution pipe, the third bracket net is installed on the inner wall of the tank body and is perpendicular to the tank body axis, the third bracket net is located between the anaerobic reaction zone and the sewage collection zone, the vertical flow sedimentator is installed on the third bracket net, the vertical flow sedimentator includes an outer shell and an inner shell, the water inlet reflector is installed on the top of the inner shell, the projection area of ​​the water inlet reflector with respect to the tank body axis direction is half of the projection area of ​​the outer shell with respect to the tank body axis direction, one end of the water distribution pipe is connected to the water inlet, and the other end of the water distribution pipe passes through the anaerobic reaction zone and is located in the inner shell with the port facing upward.

[0011] Preferably, the anaerobic reaction zone includes an air-water backwash pipe, biochemical balls and ceramsite, the biochemical balls and ceramsite are filled between the outer shell and the inner wall of the tank body, the air-water backwash pipe is installed on the third bracket net, the water distribution pipe consists of a horizontal part and a vertical part, the water distribution pipe consists of a horizontal part and a vertical part, the end of the horizontal part is connected to the water inlet, and the vertical part and the vertical flow settler are coaxial with the tank body.

[0012] Preferably, the sewage collecting area comprises a conical bucket, one end of the cone top of the conical bucket is connected to the sewage outlet, and the other end of the conical bucket is connected to the third bracket net.

[0013] Preferably, the PD / A reaction zone is filled with 25%-35% of biological filler.

[0014] An integrated anaerobic ammonium oxidation denitrification process for aquaculture includes the above-mentioned integrated anaerobic ammonium oxidation denitrification device for aquaculture, and the production process steps are as follows:

[0015] S1: The water is taken in from the aquaculture tail water collection pool (sewage collection pool). The tail water enters the tank through the water distribution pipe. The water contains COD, and After the vertical flow sedimentation area, rapid sedimentation and degradation occur in the vertical flow sedimentation area, reducing the DO concentration, and the sludge will enter the sewage collection area;

[0016] S2: After passing through the vertical flow sedimentation area, 50% and Will enter the anaerobic reaction zone, where it will be degraded and accumulated and CO2, DO will inhibit -N generates, thereby accumulating Some of the settled sludge will enter the sewage collection area;

[0017] S3: Leaving from the anaerobic reaction zone and CO2 will enter the PD / A reaction zone, and the remaining 50% in the vertical flow sedimentation zone and It will also enter the PD / A reaction zone. Under the anaerobic ammonium oxidizing bacteria and hypoxic conditions in the PD / A reaction zone, the remaining Restore to and It will be oxidized into N2, thus denitrifying the tail water;

[0018] S4: The tail water after denitrification passes through the filter cotton and enters the clean water area, and is finally discharged from the water outlet, and N2 will be discharged from the exhaust port.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The denitrification equipment of the present invention requires less aeration, and the theoretical oxygen demand is only 50% of that of the traditional process; in aquaculture, it is completely satisfied by the high DO concentration water inlet of the breeding link, that is, the system; only intermittent and small amount of aeration is required for the turnover of MBBR fillers and bottom backwashing.

[0021] 2. The denitrification equipment of the present invention consumes less organic matter than the prior art, and short-range denitrification consumes only 20% of the carbon source, saving 80% of the carbon source; and because the tail water comes from the aquaculture tail water collection pool (sewage collection pool), the aquaculture tail water does not lack COD.

[0022] 3. The denitrification equipment of the present invention saves the floor space of water treatment facilities, and does not require additional facilities such as primary sedimentation tanks, secondary sedimentation tanks, and nitrification tanks, thereby reducing floor space and equipment investment.

[0023] 4. The denitrification equipment of the present invention has lower energy consumption than the existing equipment. Only the pressurized water inlet pump at the water inlet requires energy consumption, which reduces the operating cost.

[0024] 5. The denitrification equipment process of the present invention is an anaerobic ammonia oxidation denitrification process (PD / A) based on partial denitrification, which is beneficial to enrich the functional microorganisms in the culture reactor and improve the exposure level of the substrate, overcome the defect that the traditional full nitrification and denitrification process is not suitable for the treatment of aquaculture tailwater with large flow, low nitrogen load and low C / N, and improve the denitrification efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0026] Figure 1 It is a schematic diagram of the structure of the device of the present invention;

[0027] Figure 2 It is a process flow chart of the present invention.

[0028] 1. Tank body; 2. Exhaust port; 3. Drain port; 4. Water outlet; 5. Water inlet; 6. First bracket net; 7. Second bracket net; 8. Inner tube bracket; 9. Third bracket net; 10. Filter cotton; 11. Inner tube; 12. Guide net; 13. Inner tube guide plate; 14. Air distribution pipe; 15. Air-water backwash pipe; 16. Vertical flow precipitator; 1601, outer shell; 1602, inner shell; 17. Water distribution pipe; 18. Conical bucket; 19. Water quality detection port; 20. Water inlet reflector; 21. Biological filler. DETAILED DESCRIPTION

[0029] The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Next, the working principle in this embodiment is described in detail so that those skilled in the art can better understand the present invention:

[0031] refer to Figure 1An anaerobic ammonia oxidation water treatment device includes a tank body 1, a vent 2 is provided on the top of the tank body 1, a sewage outlet 3 is provided on the bottom of the tank body 1, a water outlet 4 and a water inlet 5 are provided on the side walls of the tank body 1, and the inside of the tank body 1 is divided into a clean water area, a PD / A reaction area, an anaerobic reaction area, a vertical flow sedimentation area and a sewage collection area from top to bottom. Water quality detection ports 19 are provided on the side walls of the tank body 1 located in the anaerobic reaction area and the PD / A reaction area. The water quality detection port 19 of the anaerobic reaction area is located at the top of the anaerobic reaction area, and is used to detect the substrate concentration of the effluent from the anaerobic area, as well as the accumulation of substrates such as ammonia nitrogen and nitrite and the reduction of dissolved oxygen. The water quality detection port 19 of the PD / A reaction area is used to detect the ammonia nitrogen, nitrite removal and dissolved oxygen control, temperature conditions, etc. of the water sample in the PD / A reaction area.

[0032] The clean water area includes a first bracket net 6 and filter cotton 10. The first bracket net 6 is installed on the inner wall of the tank body 1 and is perpendicular to the axis of the tank body 1. The filter cotton 10 is installed on the first bracket net 6 and is used to filter the tail water after treatment in the PD / A reaction area. The water outlet 4 is located above the filter cotton 10. The tail water filtered by the filter cotton 10 has achieved the effect of denitrification, so it is discharged from the water outlet 4, and the N2 generated in the PD / A reaction area will be discharged from the exhaust port 2.

[0033] The PD / A reaction zone includes a second bracket net 7, an inner tube bracket 8, an inner tube 11, a guide net 12, an inner tube guide plate 13 and an air distribution pipe 14. The second bracket net 7 is installed on the inner wall of the tank body 1 and is perpendicular to the axis of the tank body 1. One end of the guide net 12 is installed on the second bracket net 7. The guide net 12 is used to guide the tail water floating from the vertical flow sedimentation area into the inner tube 11. After leaving the end of the inner tube 11 away from the guide net 12, part of it flows downward to the guide net 12 to form a circulation flow, ensuring that the tail water is fully reacted in the PD / A reaction zone. The inner tube bracket 8 is installed on the inner wall of the tank body 1 and is perpendicular to the axis of the tank body 1. The inner tube bracket 8 is located between the second bracket net 7 and the clear water area. The air distribution pipe 14 is installed on the side of the second bracket net 8 away from the guide net 12. The air distribution pipe is spirally arranged on the second bracket net with 2-3 circles to increase the uniformity of air distribution. The gas introduced by the air distribution pipe 14 is air, which is used to roll the biological filler 21. The COD degradation in the anaerobic reaction zone will produce a large amount of CO2 that rises into the PD / A reaction zone. Under the action of anaerobic ammonia oxidizing bacteria, CO2 and the tail water The reaction generates N2, and the nitrogen in the tail water is separated. The inner cylinder 11 is installed on the inner cylinder bracket 8, and the inner cylinder guide plate 13 is installed at one end of the inner cylinder 11 close to the guide net 12. The inner cylinder 11 and the guide net 12 are coaxial with the tank body 1. The inner cylinder guide plate 13 is used to guide most of the water floating up from the vertical flow sedimentation area to enter the inner cylinder 11 to ensure the stability of the circulating water flow.

[0034] The guide net 12 is trumpet-shaped and opens upward. The end of the guide net 12 away from the second bracket net 7 is connected to the inner wall of the tank body 1. The inner cylinder guide plate 13 is trumpet-shaped and opens downward, and is used to guide the biological filler 21 that sinks with the downflow to gather on the second bracket net 7, and rise into the inner cylinder 11 under the push of the air from the air distribution pipe 14, so as to ensure that the biological filler 21 is evenly circulated and turned, fully contacting the water matrix and reacting. The end of the guide net 12 close to the second bracket net 7 is not provided with a filter hole.

[0035] The PD / A reaction zone is filled with 30% volume, such as K3 / K5 / SDC, which is used to intercept and adsorb activated sludge, domesticate and enrich anaerobic ammonia oxidizing bacteria, and the biological filler 21 maintains a volume density of 25%-35%, which is more conducive to the growth of anaerobic ammonia oxidizing bacteria. Anaerobic ammonia oxidizing bacteria use CO2 or Cell synthesis.

[0036] The anaerobic reaction zone includes an air-water backwash pipe 15, biochemical balls and ceramsite, and the space between the outer shell 1601 and the inner wall of the tank body 1 is filled with biochemical balls and ceramsite. The air-water backwash pipe 15 is installed on the third bracket net 9, and is used for backwashing to prevent the anaerobic layer filler from clogging after long-term use. The anaerobic reaction zone is used to degrade suspended solids and soluble COD in the water, respectively through the ammonification of organic matter by ammonifying bacteria and the nitrate nitrogen by low dissolved oxygen (DO). Short-term denitrification produces accumulation and Continuously provide sufficient concentration of reaction substrate for the denitrification reaction in the PD / A reaction zone to improve the denitrification effect.

[0037] The vertical flow sedimentation area includes a vertical flow sedimentator 16, a third bracket net 9, a water inlet reflector 20 and a water distribution pipe 17. The third bracket net 9 is installed on the inner wall of the tank body 1 and is perpendicular to the axis of the tank body 1. The third bracket net 9 is located between the anaerobic reaction area and the sewage collection area. The vertical flow sedimentator 16 is installed on the third bracket net 9. The vertical flow sedimentator 16 includes an outer shell 1601 and an inner shell 1602. The water inlet reflector 20 is installed on the top of the inner shell 1602, which is used to reflect the inlet water, limit the flow and guide the sludge settled in the PD / A reaction area to the bottom sewage collection area. The projection area of ​​the water inlet reflector 20 about the axis direction of the tank body 1 is half of the projection area of ​​the outer shell 1601 about the axis direction of the tank body 1, which limits 50% of the inlet water from entering the PD / A reaction area through the anaerobic area, and the other 50% of the inlet water rises from between the outer shell 1601 and the inner shell 1602 after sedimentation and enters the PD / A reaction area. One end of the water distribution pipe 17 is connected to the water inlet 5, and the other end of the water distribution pipe passes through the anaerobic reaction zone and is located in the inner shell with the port facing upward. The vertical flow sedimentator 16 is used to allow the sludge in the tail water to settle in the sewage collection area for collection and discharge. The tail water received by the water inlet 5 comes from the aquaculture tail water collection pool, and the aquaculture tail water is not short of COD, which is less than the existing technology. Short-range denitrification only consumes 20% of the carbon source, saving 80% of the carbon source.

[0038] The water distribution pipe 17 consists of a horizontal part and a vertical part. The end of the horizontal part is connected to the water inlet 5, and the vertical part and the vertical flow settler 16 are coaxial with the tank body 1. The water distribution can allow the tail water to fully react with the vertical flow settler 16, so that the sludge can be better precipitated and separated.

[0039] The sewage collecting area includes a conical bucket 18 , one end of the cone top of the conical bucket 18 is connected to the sewage outlet 3 , and the other end of the conical bucket 18 is connected to the third bracket net 9 .

[0040] refer to Figure 2 , the process flow of this device is:

[0041] S1: water enters from the aquaculture tailwater collection tank (sewage collection tank), and the tailwater enters the tank body 1 through the water distribution pipe 17. and After the vertical flow sedimentation area, rapid sedimentation and degradation occur in the vertical flow sedimentation area, reducing the DO concentration, and the sludge will enter the sewage collection area;

[0042] S2: After passing through the vertical flow sedimentation area, 50% and Will enter the anaerobic reaction zone, where it will be degraded and accumulated and CO2, DO will inhibit Generate, thereby accumulate Some of the settled sludge will enter the sewage collection area;

[0043] S3: Leaving from the anaerobic reaction zone and CO2 will enter the PD / A reaction zone, and the remaining 50% in the vertical flow sedimentation zone and It will also enter the PD / A reaction zone. Under the anaerobic ammonia oxidizing bacteria and hypoxic conditions in the PD / A reaction zone, the remaining Restore to and It will be oxidized into N2, thus denitrifying the tail water;

[0044] S4: The tail water after denitrification passes through the filter cotton and enters the clean water area, and is finally discharged from the water outlet, and N2 will be discharged from the exhaust port.

[0045] The equipment of the present invention is started and pre-operated with the following steps:

[0046] (1) Pre-cultivation of anaerobic ammonium oxidizing bacteria, using biofilm sludge rich in anaerobic ammonium oxidizing bacteria as the inoculation source for rapid equipment startup;

[0047] (2) Using MBBR hydrophilic biological filler 21 to intercept and adsorb activated sludge, domesticate and enrich anaerobic ammonia-oxidizing bacteria, with a filling rate of 30%;

[0048] (3) Intermittent aeration and strict control of DO (≤1 mg / L);

[0049] (4) Control the temperature (25-35°C, which is basically consistent with the 20-30°C in aquaculture);

[0050] (5) Control pH value (7-8.5, which is completely consistent with aquaculture requirements).

[0051] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An integrated anaerobic ammonium oxidation denitrification device for aquaculture, characterized in that: The invention comprises a tank body (1), wherein the top of the tank body (1) is provided with an exhaust port (2), the bottom of the tank body (1) is provided with a sewage outlet (3), the side walls of the tank body (1) are provided with a water outlet (4) and a water inlet (5), the interior of the tank body (1) is respectively divided into a clean water area, a PD / A reaction area, an anaerobic reaction area, a vertical flow sedimentation area and a sewage collection area from top to bottom, and the side walls of the tank body (1) located in the anaerobic reaction area and the PD / A reaction area are provided with water quality detection ports (19).

2. The integrated anaerobic ammonium oxidation denitrification device for aquaculture according to claim 1, characterized in that: The clean water zone comprises a first bracket net (6) and filter cotton (10), wherein the first bracket net (6) is mounted on the inner wall of the tank body (1) and is perpendicular to the axis of the tank body (1), and the filter cotton (10) is mounted on the first bracket net (6) and is used to filter the tail water after treatment in the PD / A reaction zone, and the water outlet (4) is located above the filter cotton (10).

3. The integrated anaerobic ammonium oxidation denitrification device for aquaculture according to claim 1, characterized in that: The PD / A reaction zone comprises a second bracket net (7), an inner tube support (8), an inner tube (11), a guide net (12), an inner tube guide plate (13) and an air distribution pipe (14); the second bracket net (7) is mounted on the inner side wall of the tank body (1) and is perpendicular to the axis of the tank body (1); one end of the guide net (12) is mounted on the second bracket net (7); the inner tube support (8) is mounted on the inner side wall of the tank body (1) and is perpendicular to the axis of the tank body (1); the inner tube support (8) is located between the second bracket net (7) and the clean water zone; the air distribution pipe (14) is mounted on a side of the second bracket net (7) away from the guide net (12); the inner tube (11) is mounted on the inner tube support (8); the inner tube guide plate (13) is mounted on one end of the inner tube (11) close to the guide net (12); the inner tube (11) and the guide net (12) are coaxial with the tank body (1).

4. The integrated anaerobic ammonium oxidation denitrification device for aquaculture according to claim 3, characterized in that: The guide net (12) is trumpet-shaped and has an opening facing upwards; one end of the guide net (12) away from the second bracket net (7) is connected to the inner wall of the tank body (1); the inner cylinder guide plate (13) is trumpet-shaped and has an opening facing downwards; and one end of the guide net (12) close to the second bracket net (7) is not provided with a filtering hole.

5. The integrated anaerobic ammonium oxidation denitrification device for aquaculture according to claim 3, characterized in that: The gas distribution pipe (14) is spirally arranged on the second bracket net (7) for 2-3 turns, and the gas introduced by the gas distribution pipe (14) is air.

6. The aquaculture integrated anaerobic ammonium oxidation denitrification device according to claim 1, characterized in that: The vertical flow sedimentation area comprises a vertical flow sedimentation tank (16), a third bracket net (9), a water inlet reflector (20) and a water distribution pipe (17). The third bracket net (9) is installed on the inner side wall of the tank body (1) and is perpendicular to the axis of the tank body (1). The third bracket net (9) is located between the anaerobic reaction area and the sewage collection area. The vertical flow sedimentation tank (16) is installed on the third bracket net (9). The vertical flow sedimentation tank (16) comprises an outer shell (1601) and an inner shell (1602). The water inlet reflector (20) is installed on the top of the inner shell (1602). The projection area of ​​the water inlet reflector (20) with respect to the axis direction of the tank body (1) is half of the projection area of ​​the outer shell (1601) with respect to the axis direction of the tank body (1). One end of the water distribution pipe (17) is connected to the water inlet (5), and the other end of the water distribution pipe (17) passes through the anaerobic reaction area and is located in the inner shell (1602) with the port facing upward.

7. The integrated anaerobic ammonium oxidation denitrification device for aquaculture according to claim 6, characterized in that: The anaerobic reaction zone comprises an air-water backwash pipe (15), biochemical balls and ceramsite; the space between the outer shell (1601) and the inner wall of the tank body (1) is filled with biochemical balls and ceramsite; the air-water backwash pipe (15) is installed on a third bracket net (9); the water distribution pipe (17) consists of a horizontal portion and a vertical portion; the end of the horizontal portion is connected to the water inlet (5); the vertical portion and the vertical flow settler (16) are coaxial with the tank body (1).

8. The integrated anaerobic ammonium oxidation denitrification device for aquaculture according to claim 6, characterized in that: The sewage collection area comprises a conical bucket (18), one end of the cone top of the conical bucket (18) is connected to the sewage outlet (3), and the other end of the conical bucket (18) is connected to the third bracket network (9).

9. The integrated anaerobic ammonium oxidation denitrification device for aquaculture according to claim 3, characterized in that: The PD / A reaction area is filled with 25%-35% of biological filler (21).

10. An integrated anaerobic ammonium oxidation denitrification process for aquaculture, using an integrated anaerobic ammonium oxidation denitrification device for aquaculture according to any one of claims 1 to 9, characterized in that: S1: water is taken in from the aquaculture tail water collection pool. The tail water enters the tank (1) through the water distribution pipe (17). The water contains COD, N, DO, -N and -N, after the vertical flow sedimentation area, rapid sedimentation and degradation occur in the vertical flow sedimentation area, reducing the DO concentration, and the sludge will enter the sewage collection area; S2: After passing through the vertical flow sedimentation area, 50% -N and -N will enter the anaerobic reaction zone, where it will be degraded and accumulated. and CO2, DO will inhibit -N generates, thereby accumulating -N, part of the settled sludge will enter the sewage collection area; S3: Leaving from the anaerobic reaction zone -N and CO2 will enter the PD / A reaction zone, and the remaining 50% in the vertical flow sedimentation zone -N and -N will also enter the PD / A reaction zone. Under the anaerobic ammonium oxidizing bacteria and hypoxic conditions in the PD / A reaction zone, the remaining -N Restore to -N, -N and N will be oxidized to N2, thus denitrifying the tailwater; S4: The tail water after denitrification passes through the filter cotton and enters the clean water area, and is finally discharged from the water outlet, and N2 will be discharged from the exhaust port.

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