Integrated three-stage high-efficiency biological denitrification device

Abstract

The present application belongs to the technical field of biological denitrification of aquaculture water, and particularly relates to an integrated three-stage high-efficiency biological denitrification device. The device comprises a water purification zone, a reaction zone and a bottom sewage discharge zone. The reaction zone comprises a microbead medium nitrification reaction zone, an aerobic nitrification reaction zone and a denitrification reaction zone. The denitrification reaction zone is arranged below the microbead medium nitrification reaction zone, and the aerobic nitrification reaction zone is arranged at the periphery of the denitrification reaction zone. The aquaculture water sequentially passes through the microbead medium nitrification reaction zone, the denitrification reaction zone and the aerobic nitrification reaction zone for three-stage biological denitrification. The water purification zone is arranged above the aerobic nitrification reaction zone. The bottom sewage discharge zone is arranged at the bottom of the reaction zone and is provided with a self-circulation system and an air inlet system. The self-circulation system provides a high-pressure water flow for disturbance to the denitrification reaction zone. The air inlet system provides a gas flow for increasing the oxygen dissolution rate to the aerobic nitrification reaction zone. The present application realizes the integration of nitrification and denitrification in the same device, and achieves the high-intensification and modularization of the device.

Description

Technical Field

[0001] This invention belongs to the field of biological denitrification technology in aquaculture water, and specifically relates to an integrated three-stage high-efficiency biological denitrification device. Background Technology

[0002] In recirculating aquaculture systems (RAS), uneaten feed and feces from farmed animals accumulate and decompose, primarily existing in the water as ammonia nitrogen and nitrite nitrogen. Biological filters, as a crucial water treatment unit in RAS, convert ammonia nitrogen into nitrate nitrogen through nitrification. Prolonged nitrification leads to a significant accumulation of nitrates, with concentrations reaching up to 400-500 mg / L. High nitrate concentrations threaten the survival of farmed animals and can even cause death. Currently, nitrate removal in RAS systems is mainly achieved through large-scale water exchanges, which not only wastes water resources and increases the economic burden on farmers, but also causes environmental pollution due to the discharge of nitrate-containing wastewater.

[0003] Current biological denitrification processes mainly include autotrophic, heterotrophic, and hybrid processes. However, these processes still have many problems, such as slow growth rates of functional microbial communities, competition or inhibition among functional microbial communities, and difficulty in precisely controlling the amount of soluble carbon source added. Furthermore, single-stage biological denitrification devices suffer from low nitrate removal efficiency, low space utilization, and unstable operation. Therefore, there is an urgent need to design a multi-stage biological denitrification device. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide an integrated three-stage high-efficiency biological denitrification device to solve the problems of low denitrification efficiency and unstable treatment effect in existing recirculating aquaculture systems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides an integrated three-stage high-efficiency biological denitrification device, including a water purification zone, a reaction zone and a bottom sewage discharge zone;

[0007] The reaction zone includes a microsphere media nitrification reaction zone, an aerobic nitrification reaction zone, and a denitrification reaction zone. The denitrification reaction zone is located below the microsphere media nitrification reaction zone, and the aerobic nitrification reaction zone is located around the denitrification reaction zone. The aquaculture water passes through the microsphere media nitrification reaction zone, the denitrification reaction zone, and the aerobic nitrification reaction zone in sequence for three-stage biological nitrogen removal.

[0008] The water purification zone is located above the aerobic nitrification reaction zone and is used to collect aquaculture water after three-stage biological denitrification.

[0009] The bottom sludge discharge zone is located at the bottom of the reaction zone. The bottom sludge discharge zone is equipped with a self-circulation system and an air intake system. The self-circulation system is used to provide a turbulent high-pressure water flow to the denitrification reaction zone; the air intake system is used to provide an airflow to the aerobic nitrification reaction zone to increase the dissolved oxygen rate.

[0010] The microsphere medium nitration reaction zone is filled with microsphere medium, which is made of plastic particles with a density lower than that of water.

[0011] The top of the microbead media nitration reaction zone is equipped with a water inlet system;

[0012] The water inlet system includes an inlet pipe and a nozzle installed at the end of the inlet pipe. The aquaculture water introduced through the inlet pipe is sprayed into the microbead media nitrification reaction zone through the nozzle.

[0013] The denitrification reaction zone is filled with a carbon source and inoculated with denitrifying bacteria.

[0014] The carbon source is a biodegradable polymer with a stable carbon release rate.

[0015] The aerobic nitrification reaction zone has a ring structure and is filled with filter media.

[0016] The self-circulating system includes a self-circulating inlet pipe, a self-circulating outlet pipe, a self-circulating pump, and a guide plate. The self-circulating pump is located outside the bottom drainage area. The inlet of the self-circulating pump is connected to the bottom drainage area through the self-circulating inlet pipe. The outlet of the self-circulating pump is connected to one end of the self-circulating outlet pipe. The other end of the self-circulating outlet pipe is located inside the bottom drainage area and connected to the guide plate. The guide plate is located at the bottom of the denitrification reaction zone and is used to generate a high-pressure water flow.

[0017] The air intake system includes an air supply pipe, an air pump, and aeration discs. The air supply pipe is arranged circumferentially at the bottom of the aerobic nitrification reaction zone. The air inlet end of the air supply pipe passes through the bottom sewage discharge area and is connected to the air pump. Multiple aeration discs are installed on the air supply pipe to distribute the airflow evenly.

[0018] The bottom of the bottom sewage discharge area has a conical structure, and the bottom end of the conical structure is connected to the sewage discharge pipe.

[0019] The integrated three-stage high-efficiency biological nitrogen removal device includes a concentric outer shell and an inner shell. The microsphere medium nitrification reaction zone, the denitrification reaction zone, and the nitrification reaction zone are separated by a grate plate. The microsphere medium nitrification reaction zone and the denitrification reaction zone are located in the inner cavity, and the aerobic nitrification reaction zone is located between the outer shell and the inner shell.

[0020] The advantages and beneficial effects of this invention are:

[0021] 1. This invention has a two-layer structure, namely, the inner cavity is a microbead medium nitrification reaction zone and a denitrification reaction zone, and the outer cavity is an annular aerobic nitrification reaction zone. The three zones are separated into relatively independent spaces, avoiding competition between denitrifying bacteria and aerobic bacteria, providing the most suitable living environment for each type of bacteria, and maximizing the performance of the reactor for long-term stable operation.

[0022] 2. The microsphere media reaction zone of the present invention uses plastic granule media with a large specific surface area and small volume, which is smaller in volume than other nitrifying biological filters.

[0023] 3. The present invention integrates nitrification and denitrification reactions into a single device, achieving a high degree of integration and modularization of the biological denitrification device.

[0024] 4. The novel biodegradable polymer carbon source selected in this invention has a stable carbon release rate and can provide a stable carbon source for the device over a long period of time. Solid-phase denitration is a novel denitrification process that provides non-dissolved solid organic matter as a carbon source, avoiding the risk of excessive or insufficient carbon source addition. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of an integrated three-stage high-efficiency biological denitrification device according to the present invention;

[0026] Figure 2 This is a top view of an integrated three-stage high-efficiency biological denitrification device according to the present invention;

[0027] Figure 3 This is a schematic diagram of the structure of the microbead medium nitration reaction zone in this invention.

[0028] In the diagram: 1 is the microsphere media nitrification reaction zone, 2 is the aerobic nitrification reaction zone, 3 is the aeration disc, 4 is the self-circulating water inlet pipe, 5 is the drain outlet, 6 is the drain pipe, 7 is the water inlet pipe, 8 is the water outlet pipe, 9 is the grate plate, 10 is the self-circulating water outlet pipe, 11 is the air supply pipe, 12 is the self-circulating water pump, 13 is the air pump, 14 is the denitrification reaction zone, 15 is the nozzle, 16 is the guide plate, 17 is the outer shell, and 18 is the inner shell. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figures 1 to 3As shown, this invention provides an integrated three-stage high-efficiency biological denitrification device, including a water purification zone, a reaction zone, and a bottom sludge discharge zone. The reaction zone includes a microsphere-based nitrification reaction zone 1, an aerobic nitrification reaction zone 2, and a denitrification reaction zone 14. The denitrification reaction zone 14 is located below the microsphere-based nitrification reaction zone 1, and the aerobic nitrification reaction zone 2 is located around the denitrification reaction zone 14. Aquaculture water sequentially passes through the microsphere-based nitrification reaction zone 1, the denitrification reaction zone 14, and the aerobic nitrification reaction zone 2 for three-stage biological denitrification. The water purification zone is located above the aerobic nitrification reaction zone 2 and is used to collect the aquaculture water after the three-stage biological denitrification. The bottom sludge discharge zone is located at the bottom of the reaction zone and includes a self-circulation system and an air intake system. The self-circulation system provides a turbulent high-pressure water flow to the denitrification reaction zone 14, and the air intake system provides an airflow to the aerobic nitrification reaction zone 2 to increase dissolved oxygen levels.

[0031] like Figure 1 , Figure 3 As shown in the embodiment of the present invention, a water inlet system is provided at the top of the microsphere medium nitrification reaction zone 1; the water inlet system includes a water inlet pipe 7 and a nozzle 15 disposed at the end of the water inlet pipe 7, and the aquaculture water introduced by the water inlet pipe 7 is sprayed into the microsphere medium nitrification reaction zone 1 through the nozzle 15.

[0032] In this embodiment of the invention, the interior of the microsphere medium nitrification reaction zone 1 is filled with microsphere medium, which is made of plastic particles with a density lower than that of water. The plastic particles have a small volume and a large specific surface area; the microsphere medium reaction zone 1 receives water by spraying from the upper nozzle 15, and the water exits from the bottom into the aerobic nitrification reaction zone 2.

[0033] In embodiments of the present invention, the denitrification reaction zone 14 is filled with a carbon source and inoculated with denitrifying bacteria. Specifically, the organic carbon source is a biodegradable polymer with a stable carbon release rate, such as poly(ε-caprolactone) (PCL), which can stably and efficiently provide a carbon source for the device; the carbon source filling volume accounts for 33% of the effective volume of the denitrification reaction zone 14.

[0034] Specifically, denitrifying bacteria are anaerobic heterotrophic bacteria. Under the catalysis of organic carbon sources, denitrifying bacteria multiply rapidly, while simultaneously consuming NO3. - -N is used to provide the oxygen needed for reproduction. The reproduction cycle of denitrifying bacteria is roughly similar to that of nitrite bacteria. Under all conditions (anaerobic, temperature, organic carbon source, etc.), the entire denitrification system only takes about one to two weeks from start to maturity.

[0035] In an embodiment of the present invention, the aerobic nitrification reaction zone 2 has a ring structure and is filled with filter media. The water purification zone above the aerobic nitrification reaction zone 2 also has a ring structure, and the side wall of the water purification zone is provided with an outlet pipe 8.

[0036] like Figure 1 , Figure 2 As shown, in an embodiment of the present invention, the self-circulating system includes a self-circulating inlet pipe 4, a self-circulating outlet pipe 10, a self-circulating water pump 12, and a guide plate 16. The self-circulating water pump 12 is located outside the bottom drainage area. The inlet of the self-circulating water pump 12 is connected to the bottom drainage area through the self-circulating inlet pipe 4. The outlet of the self-circulating water pump 12 is connected to one end of the self-circulating outlet pipe 10. The other end of the self-circulating outlet pipe 10 is located within the bottom drainage area and connected to the guide plate 16. The guide plate 16 is located at the bottom of the denitrification reaction zone 14 and is used to evenly distribute the high-pressure water flow injected into the denitrification reaction zone 14. The high-pressure water flow fluidizes the carbon source within the denitrification reaction zone 14. Specifically, the self-circulating water pump 12 is a stainless steel jet-type self-priming pump.

[0037] Furthermore, the bottom of the denitrification reaction zone 14 adopts a conical structure to enhance the disturbance function of the high-pressure water flow.

[0038] like Figure 1 , Figure 2 As shown in the embodiment of the present invention, the air intake system includes an air supply pipe 11, an air pump 13, and aeration discs 3. The air supply pipe 11 is arranged circumferentially at the bottom of the aerobic nitrification reaction zone 2. The air inlet end of the air supply pipe 11 extends from the bottom sewage discharge area and is connected to the air pump 13. Multiple aeration discs 3 are installed on the air supply pipe 11. The aeration discs 3 are used to evenly distribute the airflow. The airflow keeps the filter media inside the annular aerobic nitrification reaction zone 2 in a fluidized state and at a high dissolved oxygen level. Specifically, four aeration discs 3 are evenly distributed on the air supply pipe 11, and the air pump 13 is a high-pressure vortex blower.

[0039] like Figure 1 As shown in the embodiment of the present invention, the bottom of the bottom sewage discharge area is a conical structure, and the bottom end of the conical structure is provided with a sewage discharge port, which is connected to the sewage discharge pipe 6.

[0040] Specifically, the integrated three-stage high-efficiency biological nitrogen removal device provided by the present invention includes a coaxially mounted outer shell 17 and an inner shell 18, both of which are cylindrical. The interior of the inner shell 18 and the space between the outer shell 17 and the inner shell 18 are divided into three reaction zones by a grate plate 9. The microsphere media nitrification reaction zone 1 and the denitrification reaction zone 14 are located inside the inner shell 18, and the aerobic nitrification reaction zone 2 is located between the outer shell 17 and the inner shell 18. The microspheres filled in the microsphere media reaction zone 1, the carbon source filled in the denitrification reaction zone 14, and the filter media filled in the aerobic nitrification reaction zone 2 are all isolated in their respective reaction zones by the grate plate 9.

[0041] This invention provides an integrated three-stage high-efficiency biological nitrogen removal device, consisting of an inner and outer layer structure. The inner cavity comprises a microsphere-based nitrification reaction zone and a denitrification reaction zone, while the outer cavity is an annular aerobic nitrification reaction zone. These three zones are separated into relatively independent spaces, avoiding competition between denitrifying bacteria and aerobic bacteria, providing an optimal living environment for each type of bacteria, and maximizing the long-term stable operation of the reactor. This invention integrates autotrophic and heterotrophic nitrogen removal, employing a method of water inlet at the upper middle section and water outlet at the upper end of the outer annular zone. High-pressure water flow keeps the carbon source in the denitrification reaction zone 14 fluidized, while airflow keeps the filter media inside the annular aerobic nitrification reaction zone 2 fluidized and at a high dissolved oxygen level. This invention organically integrates nitrification and denitrification, achieving a high degree of integration and modularity in the biological nitrogen removal device. The device has a simple structure, is easy to operate, and can effectively improve the nitrogen removal effect in aquaculture water, ensuring efficient and stable reactor operation.

[0042] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, extensions, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. An integrated three-stage high-efficiency biological nitrogen removal device, characterized in that, Includes a water purification area, a reaction area, and a bottom sewage discharge area; The reaction zone includes a microsphere media nitrification reaction zone (1), an aerobic nitrification reaction zone (2), and a denitrification reaction zone (14). The denitrification reaction zone (14) is located below the microsphere media nitrification reaction zone (1), and the aerobic nitrification reaction zone (2) is located around the denitrification reaction zone (14). The aquaculture water passes through the microsphere media nitrification reaction zone (1), the denitrification reaction zone (14), and the aerobic nitrification reaction zone (2) in sequence for three-stage biological denitrification. The water purification zone is located above the aerobic nitrification reaction zone (2). The water purification zone is used to collect the aquaculture water after the three-stage biological denitrification. The bottom sludge zone is located at the bottom of the reaction zone. The bottom sludge zone is equipped with a self-circulation system and an air intake system. The self-circulation system is used to provide a turbulent high-pressure water flow to the denitrification reaction zone (14); the air intake system is used to provide airflow to the aerobic nitrification reaction zone (2) to improve the dissolved oxygen rate. The microsphere medium nitration reaction zone (1) is filled with microsphere medium, which is made of plastic particles with a density lower than that of water. The denitrification reaction zone (14) is filled with a carbon source and inoculated with denitrifying bacteria; the carbon source is a biodegradable polymer with a stable carbon release rate. The aerobic nitrification reaction zone (2) has a ring structure and is filled with filter media. The self-circulating system includes a self-circulating inlet pipe (4), a self-circulating outlet pipe (10), a self-circulating water pump (12), and a guide plate (16). The self-circulating water pump (12) is located outside the bottom sewage area. The inlet of the self-circulating water pump (12) is connected to the bottom sewage area through the self-circulating inlet pipe (4). The outlet of the self-circulating water pump (12) is connected to one end of the self-circulating outlet pipe (10). The other end of the self-circulating outlet pipe (10) is located inside the bottom sewage area and connected to the guide plate (16). The guide plate (16) is located at the bottom of the denitrification reaction zone (14) and is used to form a high-pressure water flow. The air intake system includes an air supply pipe (11), an air pump (13), and an aeration disc (3). The air supply pipe (11) is arranged circumferentially at the bottom of the aerobic nitrification reaction zone (2). The air inlet end of the air supply pipe (11) passes through the bottom sewage discharge area and is connected to the air pump (13). Multiple aeration discs (3) are installed on the air supply pipe (11) and are used to distribute the airflow evenly. The bottom of the bottom sewage discharge area has a conical structure, and the bottom end of the conical structure is connected to the sewage pipe (6).

2. The integrated three-stage high-efficiency biological nitrogen removal device according to claim 1, characterized in that, The top of the microbead media nitration reaction zone (1) is equipped with a water inlet system; The water inlet system includes an inlet pipe (7) and a nozzle (15) installed at the end of the inlet pipe (7). The aquaculture water introduced by the inlet pipe (7) is sprayed into the microbead media nitrification reaction zone (1) through the nozzle (15).

3. The integrated three-stage high-efficiency biological nitrogen removal device according to any one of claims 1-2, characterized in that, The device includes a concentric outer shell (17) and an inner shell (18). The microsphere medium nitrification reaction zone (1), denitrification reaction zone (14) and aerobic nitrification reaction zone (2) are separated by a grate plate (9). The microsphere medium nitrification reaction zone (1) and denitrification reaction zone (14) are located in the inner cavity of the inner shell (18), and the aerobic nitrification reaction zone (2) is located between the outer shell (17) and the inner shell (18).

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