A method for efficiently denitrifying sewage

Abstract

The present invention discloses a method for efficiently denitrifying sewage, belonging to the field of sewage treatment technology. The method is based on a concentrically arranged outer ring water pool and inner ring water pool. The outer ring water pool is divided into an anaerobic zone and a microaerobic aeration zone by a baffle. An anaerobic ammonium oxidation and sedimentation zone is formed inside the inner ring water pool. The inner ring water pool is provided with an aeration device, a fixed moving bed biofilm reactor and a three-phase separator. Compared with the existing technology, the method adopts a "shortcut nitrification + anaerobic ammonium oxidation + precipitation" scheme, which does not require the nitrification liquid reflux process required by traditional processes. Based on optimized control parameters, the method utilizes a short-cut nitrification reaction in the microaerobic aeration zone to quickly consume dissolved oxygen, avoid the inhibition of anaerobic ammonium oxidizing bacteria by excessive dissolved oxygen, promote the coordinated symbiosis of the two functional microorganisms, rationally control the fixed moving bed biofilm reactor to ensure the effective retention of sludge, and set a three-phase separator in the inner ring to replace the traditional sedimentation tank, effectively saving equipment floor space.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and particularly relates to a method for efficiently denitrifying sewage. Background Art

[0002] Denitrification of municipal wastewater is a crucial step in wastewater treatment. While traditional biological denitrification processes are highly mature and the mainstream technology in municipal wastewater treatment plants, they still suffer from drawbacks such as high aeration volumes, high energy consumption, high carbon source dosage, and low total nitrogen removal rates due to limitations in the process itself and influent conditions. Therefore, improving denitrification efficiency, reducing energy consumption, and lowering operating costs are pressing challenges for wastewater treatment plants.

[0003] Anaerobic ammonium oxidation reaction refers to the biological reaction of anaerobic ammonium oxidizing bacteria under anoxic / anoxic conditions, using ammonia nitrogen as an electron donor and nitrite as an electron acceptor to produce nitrogen gas and a small amount of nitrate. The anaerobic ammonium oxidation process has the advantages of high denitrification efficiency and low energy consumption. However, due to the fact that nitrogen in nature is usually in the form of NH4 + 、NO3 - and organic nitrogen, NO2 - -N only exists in small amounts in some low-oxygen natural environments. It is difficult for anaerobic ammonium oxidizing bacteria to be enriched in large quantities in natural environments. Therefore, how to maintain a low-oxygen environment and ensure the normal reproduction of anaerobic ammonium oxidizing bacteria has become a major challenge for the sewage treatment industry in applying this process.

[0004] How to design an efficient wastewater denitrification method to effectively solve the above problems has become a technical challenge in this technical field. Summary of the Invention

[0005] In response to the above technical problems, the present invention provides a method for efficient denitrification of sewage, which combines the short-range nitrification process, anaerobic ammonia oxidation process and precipitation process in one reactor. The equipment is beneficial to improving the denitrification efficiency of sewage, enhancing the impact resistance of the equipment, reducing the footprint and reducing the operating costs of the sewage treatment plant.

[0006] The present invention solves the above problems through the following technical means:

[0007] A method for efficiently denitrifying sewage, comprising the following steps:

[0008] Step 1) constructing a concentrically arranged outer water pool and inner water pool, wherein: the diameter ratio of the outer water pool to the inner water pool is 1:1.5 to 1:1.8; the outer water pool is divided into an anaerobic zone and a microaerobic aeration zone by a baffle, and the volume ratio of the anaerobic zone to the microaerobic aeration zone is 1:4 to 1:2; an aeration device, a fixed moving bed biofilm reactor, and a three-phase separator are arranged in the inner water pool, and the volume ratio of the inner water pool to the microaerobic aeration zone is 1:1.5 to 1:1;

[0009] Step 2) at an ambient temperature of 20-35° C., inputting sewage into the concentrically arranged outer and inner water pools, wherein: by controlling valves on the outer and inner water inlet pipes, the ratio of water inflow from the outer and inner water pools is ensured to be 1:1.2 to 1:1.4, the dissolved oxygen in the anaerobic zone is ensured to be below 0.2 mg / L, and by controlling aeration devices at the bottom of the outer and inner water pools, the dissolved oxygen in the microaerobic aeration zone is ensured to be 1.1-1.5 mg / L, and the dissolved oxygen in the inner water pool is ensured to be 0.2-1.0 mg / L;

[0010] Step 3) Control the sludge return pipe installed in the anaerobic zone to return part of the sludge to the front end of the anaerobic zone to maintain a certain sludge concentration in the biochemical system, ensuring that the sludge return is 50%-100%;

[0011] Step 4) Control the flow propellers inside the outer and inner water pools. On the one hand, the flow propellers push water from the anaerobic zone to the microaerobic aeration zone and then to the inner water pool. On the other hand, the flow propellers ensure a balanced mixing of mud and water inside the anaerobic zone to prevent mud accumulation and sedimentation.

[0012] Step 5) Control the fixed moving bed biofilm reactor so that anaerobic ammonium oxidizing microorganisms can attach to the MBBR filler, increasing the sludge concentration of the biochemical system;

[0013] Step 6) Control the three-phase separator to ensure that the SS of the effluent is less than 10 mg / L, thereby achieving the purpose of separating gas, water and mud. The surface load of the three-phase separator is 0.60-0.75m 3 / m 2 ·h, and the precipitation time is 2.5-3h.

[0014] Preferably, the sewage input into the concentrically arranged outer and inner pools meets the following water inlet indicators:

[0015] COD≤480 mg / L, BOD5≤200 mg / L, SS≤200 mg / L, ammonia nitrogen≤35 mg / L, TN≤65 mg / L, TP≤5 mg / L, 6≤pH≤9;

[0016] The outlet water of the three-phase separator meets the following outlet water indicators:

[0017] COD≤50 mg / L, BOD5≤10mg / L, SS≤10 mg / L, ammonia nitrogen≤5mg / L, TN≤15 mg / L, TP≤0.5mg / L, 6≤pH≤9.

[0018] Preferably, the diameter of the inner water pool is in the range of 8-12 m, and the residence time of sewage in the inner water pool is 10-15 h.

[0019] Preferably, the control parameters of the inner water pool are: sludge load of 0.08-0.09 kgBOD5 / kgMLSS·d; sludge age of 15-20 days; sludge concentration of 2000-4000 mg / L, wherein the sludge concentration does not include the sludge concentration converted from filler.

[0020] Preferably, two baffles are installed in the outer circle water pool, and a baffle water hole is provided at the bottom of one of the baffles, which is used to connect the anaerobic zone and the microaerobic aeration zone. An inner circle water hole is provided at the bottom of the inner circle water pool, which is used to connect the inner circle water pool and the microaerobic aeration zone.

[0021] Preferably, the fixed moving bed biofilm reactor is an ABS material frame structure and includes a plurality of porous suspension balls, wherein a multi-porosity filler is provided in the porous suspension balls. The multi-porosity filler is mainly a three-dimensional hollow structure MBBR filler with a size between 4 and 7 mm. The gap of the fixed moving bed biofilm reactor is 450 mm to 550 mm, and the specific surface area of ​​the MBBR filler is greater than 1000 m 2 / m 3 The total volume of MBBR filler is 20%-30% of the volume of the inner pool.

[0022] Preferably, the three-phase separator is a circular separator made of PP material.

[0023] The efficient denitrification method for sewage of the present invention has the following beneficial effects:

[0024] 1) The equipment combines the short-range nitrification and anaerobic ammonium oxidation processes. In the micro-aerobic aeration zone, a short-range nitrification reaction occurs to rapidly consume dissolved oxygen, thus avoiding the inhibition of anaerobic ammonium oxidizing bacteria by excessive dissolved oxygen, promoting the coordinated symbiosis of the two functional microorganisms, and removing COD in the sewage at the same time.

[0025] 2) By controlling the dissolved oxygen range in the anaerobic ammonium oxidation zone, favorable conditions can be provided for the growth of slow-growing anaerobic ammonium oxidizing bacteria. At the same time, a fixed moving bed biofilm reactor is installed in the anaerobic ammonium oxidation zone, which makes the sludge age in the inner circle relatively long and ensures the effective retention of the sludge.

[0026] 3) By installing a three-phase separator in the inner ring to replace the traditional sedimentation tank, the equipment floor space can be effectively saved.

[0027] 4) Since the anaerobic ammonium oxidation reaction does not require a large amount of carbon source, by shortening or simplifying the reaction pathway, the sewage treatment equipment has the advantages of low investment, small amount of carbon source addition, high denitrification efficiency, and small footprint.

[0028] 5) This solution achieves optimal wastewater denitrification by controlling a variety of parameters, including the influent ratio, the volume ratio of the inner and outer pools, and dissolved oxygen control within and outside the pools. Compared to traditional A / O processes, this approach offers more efficient denitrification, eliminates the need for carbon source addition, and offers better dissolved oxygen control, facilitating the growth of anaerobic ammonium-oxidizing bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the implementation. Obviously, the drawings described below are only some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0031] Figure 2 It is a schematic diagram of the pipeline layout of the present invention;

[0032] Figure 3 It is a schematic structural diagram of the inner circle water pool of the present invention;

[0033] Figure 4 It is a schematic structural diagram of the aeration device of the present invention;

[0034] Figure 5 It is a structural schematic diagram of the fixed moving bed biofilm reactor of the present invention.

[0035] Among them, 1-outer circle water pool, 101-outer circle water inlet pipe, 102-sludge return pipe, 2-inner circle water pool, 201-inner circle water hole, 202-inner circle water inlet pipe, 3-baffle, 301-baffle water hole 4-anaerobic zone, 5-microaerobic aeration zone, 6-aeration device, 601-vent pipe, 602-aeration plate, 7-fixed moving bed biofilm reactor, 701-porous suspended ball, 8-three-phase separator, 801-outlet pipe, 802-sludge discharge pipe, 9-flow pusher. DETAILED DESCRIPTION

[0036] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0037] The present invention will be described in detail below with reference to the accompanying drawings.

[0038] A method for efficient denitrification of wastewater is based on Figures 1 to 5 The anaerobic ammonia oxidation equipment shown in the figure includes an outer circle water pool 1, an inner circle water pool 2 and a baffle 3. In the figure, the outer circle water pool 1 is concentrically arranged on the outside of the inner circle water pool 2, and two baffles 3 are arranged in the outer circle water pool 1. The baffles 3 divide the outer circle water pool 1 into an anaerobic zone 4 and a microaerobic aeration zone 5. A baffle water hole 301 is provided at the bottom of one of the baffles 3, and the bottom of the other baffle is intact. The baffle water hole 301 is used to connect the anaerobic zone 4 and the microaerobic aeration zone 5. An aeration device 6 is provided at the bottom of the microaerobic aeration zone 5. An anaerobic ammonia oxidation and precipitation zone is formed inside the inner circle water pool 2. An aeration device 6 is provided at the bottom of the inner circle water pool 2. A fixed moving bed biofilm reactor 7 is installed in the middle of the inner circle water pool 2, and a three-phase separator 8 is installed on the upper part of the inner circle water pool 2.

[0039] The efficient denitrification method for sewage comprises the following steps:

[0040] Step 1) constructing a concentrically arranged outer water pool 1 and inner water pool 2, wherein: the diameter ratio of the outer water pool 1 to the inner water pool 2 is 1:1.5 to 1:1.8; the outer water pool 1 is divided into an anaerobic zone 4 and a microaerobic aeration zone 5 by a baffle 3 within the outer water pool 1, and the volume ratio of the anaerobic zone 4 to the microaerobic aeration zone 5 is 1:4 to 1:2; an aeration device 6, a fixed moving bed biofilm reactor 7, and a three-phase separator 8 are arranged within the inner water pool 2, and the volume ratio of the inner water pool 2 to the microaerobic aeration zone 5 is 1:1.5 to 1:1;

[0041] Step 2) At an ambient temperature of 20-35°C, sewage is fed into the concentrically arranged outer water pool 1 and inner water pool 2, wherein: by controlling the valve bodies on the outer water inlet pipe 101 and the inner water inlet pipe 202, the ratio of the water inflow of the outer water pool 1 to that of the inner water pool 2 is ensured to be 1:1.2 to 1:1.4, the dissolved oxygen in the anaerobic zone 4 is ensured to be below 0.2 mg / L, and by controlling the aeration devices 6 at the bottom of the outer water pool 1 and the inner water pool 2, the dissolved oxygen in the microaerobic aeration zone 5 is ensured to be 1.1-1.5 mg / L, and the dissolved oxygen in the inner water pool 2 is ensured to be 0.2-1.0 mg / L;

[0042] Step 3) Control the sludge return pipe 102 installed in the anaerobic zone 4 to return part of the sludge to the front end of the anaerobic zone 4, so that the biochemical system maintains a certain sludge concentration and ensures that the sludge return is 50%-100%;

[0043] Step 4) Controlling the flow propellers 9 inside the outer water pool 1 and the inner water pool 2. On the one hand, the flow propellers 9 propel the water from the anaerobic zone 4 to the microaerobic aeration zone 5 and then to the inner water pool 2. On the other hand, the flow propellers 9 ensure a balanced mixing of mud and water inside the anaerobic zone 4 to prevent mud accumulation and sedimentation.

[0044] Step 5) controlling the fixed moving bed biofilm reactor 7 so that anaerobic ammonium oxidizing microorganisms can attach to the MBBR filler, thereby increasing the sludge concentration of the biochemical system;

[0045] Step 6) Control the three-phase separator 8 to ensure that the SS of the effluent is less than 10 mg / L, thereby achieving the purpose of separating gas, water and mud. The surface load of the three-phase separator 8 is 0.60-0.75 m 3 / m 2 ·h, and the precipitation time is 2.5-3h.

[0046] In specific implementation, the sewage input into the concentrically arranged outer pool 1 and inner pool 2 meets the following water inlet indicators:

[0047] COD≤480 mg / L, BOD5≤200 mg / L, SS≤200 mg / L, ammonia nitrogen≤35 mg / L, TN≤65 mg / L, TP≤5 mg / L, 6≤pH≤9;

[0048] When the water inlet indicators are unqualified, they can be adjusted by reducing the water inlet volume, adding chemicals, etc.

[0049] The outlet water of the three-phase separator 8 meets the following outlet water indicators:

[0050] COD≤50 mg / L, BOD5≤10mg / L, SS≤10 mg / L, ammonia nitrogen≤5mg / L, TN≤15 mg / L, TP≤0.5mg / L, 6≤pH≤9.

[0051] When the effluent quality is unstable, it can be adjusted by increasing the sludge concentration, adding chemicals, reducing the water intake, etc.

[0052] Specifically, the diameter of inner pool 2 ranges from 8 to 12 meters, and the wastewater retention time in inner pool 2 is 10 to 15 hours. Control parameters for inner pool 2 are: sludge loading of 0.08 to 0.09 kgBOD₅ / kgMLSS·d; sludge age of 15 to 20 days; and sludge concentration of 2000 to 4000 mg / L. The sludge concentration does not include filler-converted sludge concentration.

[0053] It should be noted that the operating personnel need to take two water samples from the inner circle pool for testing every 2-3 days. When the sludge load is too high, the sludge concentration is too high, and the sludge age is too long, the sludge discharge can be appropriately increased; when the sludge load is too low, the sludge concentration is too low, and the sludge age is too short, the sludge discharge can be appropriately reduced or a carbon source can be added to the inner circle.

[0054] In the figure, two baffles 3 are installed in the outer circle water pool 1, and a baffle water hole 301 is provided at the bottom of one of the baffles 3, and the baffle water hole 301 is used to connect the anaerobic zone 4 and the microaerobic aeration zone 5. The bottom of the inner circle water pool 2 is provided with an inner circle water hole 201, and the inner circle water hole 201 is used to connect the inner circle water pool 2 and the microaerobic aeration zone 5.

[0055] It should be noted that the bottom of the inner water tank 2 is provided with an inner water hole 201, which connects the inner water tank 2 with the micro-aerobic aeration zone 5. The inner water hole 201 is located as close as possible to the second baffle 3 to ensure that the water has a sufficient flow distance within the micro-aerobic aeration zone 5. The outer water inlet pipe 101 is installed on the upper side of the outer water tank 1, and the sludge return pipe 102 is installed on the lower side of the outer water tank 1; the inner water inlet pipe 202 is installed on the upper side of the inner water tank 2; the outlet pipe 801 is installed on the top of the three-phase separator 8, and the sludge discharge pipe 802 is installed on the bottom of the three-phase separator 8.

[0056] In the figure, the fixed moving bed biofilm reactor 7 is an ABS frame structure and includes a plurality of porous suspension balls 701. The porous suspension balls 701 are provided with multi-porosity fillers. The multi-porosity fillers are mainly three-dimensional hollow structure MBBR fillers with a size between 4-7 mm. The gap of the fixed moving bed biofilm reactor is 450 mm to 550 mm, and the specific surface area of ​​the MBBR filler is greater than 1000 m 2 / m 3 The total volume of MBBR filler is 20%-30% of the volume of the inner pool 2.

[0057] Specifically, the fixed moving bed biofilm reactor 7 can be an ABS structure with a cylindrical frame of 4000mm in diameter and 1500mm in height. The middle vertical frame is connected to a porous suspended ball of 300mm in diameter. The MBBR filler in the porous suspended ball can provide a large amount of biological attachment surface, increasing the attachment and growth area of ​​anaerobic ammonium oxidizing microorganisms. The fixed moving bed biofilm reactor 7 uses MBBR filler to form biofilms, which makes the sludge in the inner pool 2 relatively long, providing favorable conditions for the growth of slow-growing anaerobic ammonium oxidizing bacteria and ensuring the effective retention of sludge. At the same time, the filler is controlled within the porous suspended ball to prevent serious material leakage and pipe blockage in the equipment.

[0058] During actual operation, the porous filler in the reactor can attach and grow anaerobic ammonia-oxidizing bacteria to form a biofilm, which increases the number of anaerobic ammonia-oxidizing bacteria in the system and makes the inner sludge age relatively long, providing conditions for efficient denitrification; at the same time, the filler is controlled in the porous suspended balls to prevent serious problems such as material leakage and pipe blockage. The gap of the fixed moving bed biofilm reactor is 500mm, which is sufficient for the sewage to circulate and stir in the system, effectively preventing sludge blockage in the reactor.

[0059] In the figure, the three-phase separator 8 is a circular separator made of PP material, which specifically includes a water inlet area, a gas collecting chamber, a sedimentation area, a sludge discharge area and other structures. Its working principle is as follows: the water inlet area is located at the top, the sedimentation area is located in the middle, and the sludge discharge area is located at the bottom. The function of the gas collecting chamber is to release and collect gas to prevent the formation of scum and foam layers; when the sewage enters the water inlet area, it forms a circulating flow from top to bottom according to the guidance, and the mud-water mixture is fully precipitated in the sedimentation area. The separated sewage is discharged through the outlet pipe 801, and the sludge is settled in the sludge discharge area. When the sludge in the sludge discharge area accumulates to a certain extent, it can be automatically discharged through the automatic sludge discharge valve body; the three-phase separator 8 realizes the effective separation of water, gas and sludge through structural design, and forms a large flow of steam stripping by collecting the separated gas, realizing the unpowered reflux of the mud-water mixture in the system, which can replace the traditional sedimentation tank and effectively save the equipment floor space.

[0060] In actual operation, the system employs a "short-cut nitrification + anaerobic ammonium oxidation + precipitation" approach. The outer ring comprises the anaerobic and microaerobic aeration zones, while the inner ring comprises the "anaerobic ammonium oxidation + precipitation" zone. A fixed moving bed biofilm reactor and a three-phase separator are installed to return sludge to the front end of the anaerobic zone, eliminating the need for the nitrification solution return required by traditional processes. Under the same influent water quality conditions, the anaerobic ammonium oxidation system achieves stable biological denitrification, maintaining a removal rate of approximately 85%, approximately 21% higher than traditional equipment, and without the need for the addition of a carbon source.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for efficient denitrification of sewage, characterized in that: The steps include: Step 1) constructing an outer water pool (1) and an inner water pool (2) arranged concentrically, wherein: a baffle (3) is used in the outer water pool (1) to divide the outer water pool (1) into an anaerobic zone (4) and a microaerobic aeration zone (5), and the volume ratio of the anaerobic zone (4) to the microaerobic aeration zone (5) is 1:4 to 1:2; an aeration device (6), a fixed moving bed biofilm reactor (7) and a three-phase separator (8) are arranged in the inner water pool (2), and the volume ratio of the inner water pool (2) to the microaerobic aeration zone (5) is 1:1.5 to 1:1; Step 2) At an ambient temperature of 20-35° C., sewage is input into the concentrically arranged outer water pool (1) and inner water pool (2), wherein: by controlling the valve bodies on the outer water inlet pipe (101) and the inner water inlet pipe (202), the ratio of the water inflow of the outer water pool (1) to that of the inner water pool (2) is ensured to be 1:1.2 to 1:1.4, the dissolved oxygen in the anaerobic zone (4) is ensured to be below 0.2 mg / L, and by controlling the aeration devices (6) at the bottom of the outer water pool (1) and the inner water pool (2), the dissolved oxygen in the microaerobic aeration zone (5) is ensured to be 1.1-1.5 mg / L, and the dissolved oxygen in the inner water pool (2) is ensured to be 0.2-1.0 mg / L; Step 3) controlling the sludge return pipe (102) installed in the anaerobic zone (4) to return part of the sludge to the front end of the anaerobic zone (4) so ​​that the biochemical system maintains a certain sludge concentration and ensures that the sludge return is 50%-100%; Step 4) Controlling the flow pushers (9) inside the outer water pool (1) and the inner water pool (2). On the one hand, the flow pushers (9) push the water flow from the anaerobic zone (4) to the micro-aerobic aeration zone (5) and then to the inner water pool (2). On the other hand, the flow pushers (9) ensure that the mud and water inside the anaerobic zone (4) are mixed evenly to prevent mud accumulation and sedimentation. Step 5) controlling the fixed moving bed biofilm reactor (7) so that the MBBR filler is attached to the anaerobic ammonium oxidizing microorganisms, thereby increasing the sludge concentration of the biochemical system; Step 6) Control the three-phase separator (8) to ensure that the SS of the effluent is less than 10 mg / L, thereby achieving the purpose of separating gas, water and mud. The surface load of the three-phase separator (8) is 0.60-0.75 m 3 / m 2 h, the precipitation time is 2.5-3h; The sewage input into the concentrically arranged outer water pool (1) and inner water pool (2) meets the following water inlet indicators: COD≤480 mg / L, BOD5≤200 mg / L, SS≤200 mg / L, ammonia nitrogen≤35 mg / L, TN≤65 mg / L, TP≤5mg / L, 6≤pH≤9; The outlet water of the three-phase separator (8) meets the following outlet water indicators: COD≤50 mg / L, BOD5≤10 mg / L, SS≤10 mg / L, ammonia nitrogen≤5 mg / L, TN≤15 mg / L, TP≤0.5 mg / L, 6≤pH≤9; The diameter of the inner pool (2) ranges from 8 to 12 meters, and the residence time of the sewage in the inner pool (2) is 10 to 15 hours; The fixed moving bed biofilm reactor (7) is an ABS frame structure and includes a plurality of porous suspension balls (701). The porous suspension balls (701) are provided with multi-porosity fillers. The multi-porosity fillers are mainly three-dimensional hollow structure MBBR fillers with a size between 4 and 7 mm. The specific surface area of ​​the MBBR fillers is greater than 1000 m 2 / m 3 The total volume of MBBR filler is 20%-30% of the volume of the inner water pool (2).

2. A method for efficient denitrification of sewage according to claim 1, characterized in that: The control parameters of the inner water pool (2) are: sludge load of 0.08-0.09 kgBOD5 / kgMLSS·d; sludge age of 15-20 days; sludge concentration of 2000-4000 mg / L, wherein the sludge concentration does not include the sludge concentration converted from fillers.

3. A method for efficient denitrification of sewage according to claim 1, characterized in that: Two baffles (3) are installed in the outer water pool (1), wherein a baffle water hole (301) is provided at the bottom of one of the baffles (3), and the baffle water hole (301) is used to connect the anaerobic zone (4) and the micro-aerobic aeration zone (5). An inner water hole (201) is provided at the bottom of the inner water pool (2), and the inner water hole (201) is used to connect the inner water pool (2) and the micro-aerobic aeration zone (5).

4. A method for efficient denitrification of sewage according to claim 1, characterized in that: The three-phase separator (8) is a circular separator made of PP material.

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