Lateral inflow efficient biological heterotrophic and autotrophic coupling denitrification filter tank

Abstract

The utility model provides a side-inflow efficient biological heterotrophic and autotrophic coupling denitrification filter tank. The side-inflow efficient biological heterotrophic and autotrophic coupling denitrification filter tank comprises a down-flow type first filter unit and an up-flow type second filter unit, the first filtering unit and the second filtering unit are communicated through a first water passing hole formed in the bottom of the baffle plate; a filler layer is arranged in the device, and the filler layer is heterotrophic and autotrophic coupled filler; the upper edge of the water outlet tank is lower than the upper edge of the water inlet tank, the space of the reactor is effectively utilized by the filter tank, advantage complementation can be realized by a heterotrophic and autotrophic coupling method, the denitrification efficiency and the dephosphorization effect can be improved, and the sludge yield can be reduced; the whole-course self-flow design is adopted, extra lifting is not needed, and power consumption is reduced; in addition, no additional organic carbon source is needed, no additional carbon emission is generated, and the operation cost is reduced.

Description

Technical Field

[0001] This application belongs to the technical field of water treatment equipment, and particularly relates to a side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter tank. Background Art

[0002] With the rapid development of industrialization and the continuous advancement of urbanization, the impact of human activities on natural water bodies has become increasingly significant. Among them, the problem of water eutrophication has gradually emerged, becoming an important challenge affecting water quality safety and water ecological balance. As one of the key inducements of water eutrophication, the excessive discharge of nitrogen pollution not only leads to the abnormal reproduction of algae and other plankton in water bodies, but also consumes dissolved oxygen in water, affecting the survival and reproduction of aquatic organisms, and thus causing irreversible damage to the entire water ecosystem. As a key indicator for measuring the degree of nitrogen pollution in water bodies, the up-to-standard discharge of total nitrogen is of great significance for protecting the water ecological environment and achieving sustainable development.

[0003] As an effective process for controlling nitrogen pollution in water bodies, traditional heterotrophic denitrification technology is widely used in the sewage treatment process. Heterotrophic denitrification technology refers to the process of reducing nitrate (NO 3 - ) or nitrite (NO 2 - ) in water to nitrogen gas (N ) through the metabolic activities of microorganisms, so as to achieve the purpose of removing nitrogen. This technology is based on specific microbial populations (such as denitrifying bacteria), and under anoxic or microoxic conditions, uses organic carbon sources (such as methanol, glucose, etc.) as electron donors for biochemical reactions.

[0004] Traditional denitrification technology has the advantages of simple operation and high treatment efficiency, and is widely used in the sewage treatment field. However, with the increasingly strict environmental protection requirements, especially in the treatment of low carbon-nitrogen ratio (C / N) wastewater, traditional denitrification technology faces some challenges. First, for low carbon-nitrogen ratio wastewater, due to the lack of sufficient organic carbon sources, the treatment effect of traditional denitrification technology will be limited. Second, additional organic carbon sources need to be added during the traditional denitrification process, which not only increases the treatment cost, but also may bring risks of secondary pollution and high carbon emissions during the sewage treatment process.

[0005] Therefore, how to achieve the up-to-standard discharge of total nitrogen in the effluent while overcoming the limitations of traditional denitrification technology has become one of the research hotspots in the current sewage treatment field. With the progress of technology and the improvement of environmental protection requirements, the emergence of new denitrification technologies provides new solutions for the up-to-standard discharge of total nitrogen in the effluent. Utility Model Content

[0006] The embodiment of the present application provides a side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter to solve the problems existing in the related art. The technical solution is as follows:

[0007] A side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter, the filter includes a filter body and a baffle,

[0008] The baffle divides the filter into a first filtration unit flowing downward and a second filtration unit flowing upward; the first filtration unit and the second filtration unit are connected through a water passing hole arranged at the bottom of the baffle;

[0009] The filter body is provided with a water inlet tank at the upper part of the side wall of the first filtration unit and a water outlet tank at the upper part of the side wall of the second filtration unit; the height of the upper edge of the water outlet tank is lower than the height of the upper edge of the water inlet tank;

[0010] The first filtration unit and the second filtration unit are internally provided with a filler layer, and the filler is a heterotrophic and autotrophic coupled filler.

[0011] In one embodiment, the filter includes a filter plate, and the filler layer is arranged on the filter plate.

[0012] In one embodiment, long-stem filter heads are distributed on the filter plate; the gap of the long-stem filter heads is larger than the particle size of the filler.

[0013] In one embodiment, a water inlet channel is further arranged outside the filter body, and the water inlet channel is communicated with the water inlet tank through a second water passing hole.

[0014] In one embodiment, a backwashing pipe is further arranged at the bottom of the filter, and the backwashing pipe includes a backwashing air pipe and a backwashing water pipe.

[0015] In one embodiment, the filter is further provided with backwashing drainage grooves, and there are at least two backwashing drainage grooves, which are respectively arranged on the side walls on both sides of the baffle; the upper edge of the backwashing drainage groove is lower than the upper edges of the water inlet tank and the water outlet tank; the lower edge of the backwashing drainage groove is higher than the filler layer.

[0016] In one embodiment, gates are installed on the water inlet hole, the water outlet hole and the backwashing drainage groove.

[0017] In one embodiment, the filler layer accounts for 20%-60% of the volume of the filtration unit;

[0018] The filler layer in the first filtration unit is composed of 30%-60% of fillers with a particle size of 2-3 mm and 40%-70% of fillers with a particle size of 4-6 mm;

[0019] In the second filtering unit, the filler layer is composed of fillers with particle sizes of 2-3 mm and 4-6 mm, and the proportion of fillers with a particle size of 2-3 mm is not more than 15%.

[0020] In one embodiment, the main components of the filler are sulfur, iron, calcium, and carbonate.

[0021] In one embodiment, two or more groups of the filter tanks are connected in parallel.

[0022] The advantages or beneficial effects in the above technical solutions at least include:

[0023] A side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter tank of the present utility model combines the use of heterotrophic and autotrophic coupled fillers, a countercurrent flow mode of flowing in from the upper part and out from the lower part, and a side-inflow design to ensure uniform water flow distribution in the filter tank, effectively utilize the space of the reactor, and improve the volume utilization rate and treatment effect of the reactor. Among them, the heterotrophic and autotrophic coupling method can achieve complementary advantages and improve the denitrification efficiency; the whole-process gravity flow design is adopted, without additional lifting to reduce power consumption; in addition, no external organic carbon source is required, and there is no additional carbon emission.

[0024] The above summary is only for the purpose of the specification and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the present application will be readily apparent by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the drawings, unless otherwise specified, the same reference numerals throughout the several views denote the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0026] Figure 1 It is a schematic plan layout diagram of four groups of side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter tanks of the present utility model;

[0027] Figure 2 It is a sectional view of the plan layout of four groups of side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter tanks of the present utility model in the 1-1 direction;

[0028] Figure 3 It is a sectional view of the plan layout of four groups of side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter tanks of the present utility model in the 2-2 direction;

[0029] Figure 4Figure showing the change in the total nitrogen content in the wastewater before and after using the filter tank of this application for aquaculture wastewater; the upper curve is without using the filter tank of this application, and the lower curve is with using the filter tank of this application;

[0030] Among them, 1. Filter tank main body, 2. Baffle plate, 3. First filtration unit, 4. Second filtration unit, 5. First water passing hole, 6. Water inlet tank, 7. Water outlet tank, 8. Packing layer, 9. Filter plate, 10. Long-stem filter head, 11. Water inlet channel, 12. Second water passing hole, 13. Backwash pipe, 14. Backwash air pipe, 15. Backwash water pipe, 16. Backwash drainage tank, 17. Gate, 18. Rigid waterproof sleeve, 19. Outlet pipe. Detailed implementation manners

[0031] In the following text, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of this application. Therefore, the drawings and the description are considered to be exemplary in nature rather than restrictive.

[0032] The utility model discloses a side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter tank, as Figures 1-3 shown, the filter tank includes a filter tank main body 1 and a baffle plate 2. The baffle plate 2 divides the filter tank into a downward-flowing first filtration unit 3 and an upward-flowing second filtration unit 4; the first filtration unit 3 and the second filtration unit 4 are connected through a first water passing hole 5 provided at the bottom of the baffle plate 2. The filter tank main body 1 is provided with a water inlet tank 6 at the upper part of the side wall of the first filtration unit 3 and a water outlet tank 7 at the upper part of the side wall of the second filtration unit 4; the height of the upper edge of the water outlet tank 7 is lower than the height of the upper edge of the water inlet tank 6. Therefore, the filter tank adopts a full-process self-flow design, without the need for additional lifting to reduce power consumption.

[0033] The baffle plate 2 divides the filter tank into two parts, namely the first filtration unit 3 and the second filtration unit 4. The first filtration unit 3 and the second filtration unit 4 are connected at the bottom. Therefore, the first filtration unit 3 and the second filtration unit 5 of the filter tank form a two-stage folded-flow structure; the first filtration unit 3 is a downward-flowing filtration with water entering from the top and flowing out from the bottom, and the second filtration unit 4 is an upward-flowing filtration with water entering from the bottom and flowing out from the top. So the filter tank combines the downward-flowing and upward-flowing filtration forms, and the combination of the two methods achieves better denitrification. The side-inflow design ensures uniform water flow distribution in the filter tank and effectively utilizes the lateral space of the reactor, reduces the problem of excessive local load of the reactor caused by single-point water inlet, is conducive to the uniform formation of biofilm and the spatial distribution of microorganisms, and improves the volume utilization rate and treatment effect of the reactor.

[0034] The packing layers 8 provided in the first filtering unit 3 and the second filtering unit 4. On the one hand, the packing layer 8 occupies 20%-60% of the volume of the filtering unit, making full use of the space of the filtering unit. On the other hand, the packing layer 8 can make full use of the different spaces of the first filtering unit 3 and the second filtering unit 4 divided by the baffle plate 2, and different packings are used to set the packing layers 8 in the first filtering unit 3 and the second filtering unit 4, so that the packing layers 8 in the first filtering unit 3 and the second filtering unit 4 are different.

[0035] In this embodiment, the packing of the first filtering unit 3 and the second filtering unit 4 is composed of a variety of packings with different particle sizes; preferably, packings with a particle size of 2-3 mm and a particle size of 4-6 mm are used for proportioning and layout of the packing layer 8. Since the baffle plate 2 divides the filter tank into the first filtering unit 3 and the second filtering unit 4, in this embodiment, the proportions of packings with different particle sizes in the packing layer 8 in the first filtering unit 3 and the second filtering unit 4 are not the same. The particle size ratio and composition ratio of the packing are adjusted according to the water quality requirements and design. Preferably, the packing layer 38 in the first filtering unit 3 is composed of 30%-60% of the packing with a particle size of 2-3 mm and 40%-70% of the packing with a particle size of 4-6 mm; the packing layer 8 in the second filtering unit 4 is composed of the packing with a particle size of 2-3 mm and the packing with a particle size of 4-6 mm, and the proportion of the packing with a particle size of 2-3 mm does not exceed 15%. The packing layer 8 composed of packings with different particle size ratios can increase the contact time between the packing and the wastewater and the reaction effect. In this embodiment, since the wastewater is treated by the packing in the packing layer 8 of the first filtering unit 3 and the pollutant concentration drops significantly, when it enters the second filtering unit 4 again, the proportion of the packing with phosphorus-removing coupling packing in the packing layer 8 in the second filtering unit 4 increases. Through the selection and setting of the packing in the packing layer 8 in the first filtering unit 3 and the second filtering unit 4, it can be selected according to the actual situation of the wastewater, and nitrogen, phosphorus and other substances in the wastewater can be removed better and more efficiently.

[0036] In this embodiment, the packing is heterotrophic and autotrophic coupling packing. The models and functions of the packing can be various, mainly sulfur autotrophic packing containing sulfur, iron, calcium and carbonate. The sulfur autotrophic packing has a high specific surface area and porosity, can effectively intercept suspended solids, and improve the effluent water quality; the surface of the sulfur autotrophic packing is easy to form and attach biofilms. The filter tank of the present utility model combines two technologies of heterotrophic denitrification and autotrophic denitrification to efficiently remove nitrogen in sewage. Heterotrophic and autotrophic denitrification occur simultaneously when the incoming water organic matter concentration is high. Heterotrophic microorganisms use the carbon source 5C + 4NO 3 - + 2H₂O → 2N₂↑ + 4HCO 3 - + CO 2 ↑; autotrophic microorganisms use the sulfur source in the packing to carry out autotrophic denitrification: 1.10S 0 + NO3 - +0.40CO 2 +0.76H 2 O + 0.08NH 4 + →0.50N 2 ↑ + 1.10SO 4 2- +1.28H + +0.08C 5 H 7 O 2 N. Heterotrophic denitrification occurs in the presence of sufficient organic matter, synchronously removing carbon and nitrogen in the wastewater; in the state of low organic matter, sulfur, through sulfur autotrophic microorganisms such as Thiobacillus denitrificans, uses sulfur and sulfide in the filler as electron donors to reduce nitrate to nitrogen gas, achieving efficient denitrification. At the same time, heterotrophic denitrifying microorganisms can use the organic matter (COD) in the suspended solids for enhanced denitrification, so there is no need to add additional organic carbon sources, reducing the operating cost and avoiding the risk of secondary pollution while reducing the carbon emissions of the denitrification process. And the coupling of the two can achieve complementary advantages, thus significantly improving the denitrification efficiency.

[0037] The autotrophic filter media also enhance the effect of simultaneous phosphorus removal through its high specific surface area, surface voids, and partially coupled calcium carbonate in the filler. In addition to sulfur, the filler also contains calcium (Ca 2+ ) and carbonate (CO 3 2- ). When the water alkalinity is insufficient, carbonate will react with hydrogen ions to form bicarbonate (HCO 3 - ): CO 2- +H + →HCO 3 - , while neutralizing the influence of hydrogen ions, bicarbonate serves as an alkalinity supplement for the sulfur autotrophic reaction to ensure the smooth occurrence of autotrophic denitrification. A small amount of calcium ions (Ca 2+ ) dissolve and combine with phosphate (PO 4 3- ) in the water to form calcium phosphate (Ca 3 (PO 4 ) 2 ) precipitation: 3Ca 2+ +2PO 4 3- →Ca 3 (PO 4 ) 2 ↓, further removing the phosphorus in the influent water; simultaneously completing denitrification and phosphorus removal to ensure the stability of the effluent.

[0038] In this embodiment, the influent pH of the side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter is not less than 6, and the optimal pH range is 7.5 - 8.0.

[0039] In the autotrophic denitrification process, the amount of excess sludge discharged is small, greatly reducing the system sludge disposal cost. The growth rate of sulfur autotrophic denitrifying microorganisms is slow. In a pure bacterial environment, for the removal of the same total nitrogen, the growth rate of autotrophic denitrification is 2.5% - 10% of that of heterotrophic denitrifying microorganisms. Experimental data also show that autotrophic denitrification can effectively reduce the sludge production by more than 60%, greatly reducing the system sludge disposal cost.

[0040] In addition, the sulfur autotrophic filler is cheap and the raw materials are easy to obtain, which also reduces the cost; there is no auxiliary dosing system and low backwashing frequency, reducing the operation energy consumption; no external organic carbon source is required and there is no additional carbon emission; further reducing the cost.

[0041] In this embodiment, the denitrification load reaches 1.6 - 3.0 kgNO 3- N / (m 3 ·d).

[0042] In this embodiment, the head loss of the coupled denitrification filter is not less than 1 m, and it is preferably maintained at 1.5 m.

[0043] The filter includes a filter plate 9, and the packing layer 8 is arranged on the filter plate 8. The filter plate 9 supports the packing layer 8.

[0044] The long-stem filter heads 10 are distributed on the filter plate 9; the gap of the long-stem filter heads 10 is smaller than the particle size of the packing. The long-stem filter heads 10 are evenly distributed on the filter plate 9. The spacing of the long-stem filter heads 10 is selected and adjusted according to actual needs. The gap of the long-stem filter heads 10 being smaller than the particle size of the packing ensures that water flows smoothly into the subsequent treatment section while preventing the packing from flowing out.

[0045] An influent trough 6 and an effluent trough 7 are also arranged in the filter. The influent trough 6 is communicated with the second water passing hole 12; the effluent trough 7 is communicated with the outlet pipe 19. The water coming in through the second water passing hole 12 is evenly distributed to one side of the first filtering unit 3 through the influent trough 6 and enters the packing layer 8 of the filter in a down-flow manner; the water treated by the second filtering unit 4 enters the effluent trough 7 and flows out.

[0046] An influent channel 11 is also arranged outside the filter main body 1. The influent channel 11 is communicated with the influent trough 6 through the second water passing hole 12. It can ensure the continuous inflow of wastewater.

[0047] The bottom of the filter tank is also provided with a backwash pipe 13, and the backwash pipe includes a backwash air pipe 14 and a backwash water pipe 15. The biological heterotrophic and autotrophic coupled denitrification filter tank needs to be backwashed regularly according to the operation requirements. Designing a backwash trough at a lower position can effectively reduce the backwash water volume and reduce the adverse impact of the backwash water entering the water outlet trough on the water outlet.

[0048] It is determined whether backwashing is required according to the suspended solid and organic matter content in the effluent of the previous process. The backwash cycle is generally 24 hours and should not exceed 72 hours. During the initial commissioning period, the backwash cycle can be appropriately extended. In the present utility model, the backwash pipe 13 includes a backwash air pipe 14 and a backwash water pipe 15. Backwashing can be carried out by single gas flushing, single backwashing with circulating water, and combined air-water backwashing. The backwash time should not be less than 15 minutes.

[0049] The backwash pipe 13 extends to the outside of the filter tank at the bottom of the filter tank and is connected to the backwash air supply pipe and / or the backwash water supply pipe. Preferably, a rigid waterproof sleeve 18 is embedded in a side wall at the bottom of the filter tank.

[0050] The backwash gas enters the packing layer 8 through the backwash air pipe 14 and the long-stem filter head 10 via a blower, and the backwash water enters the packing layer 8 through the backwash water pipe 15 and the long-stem filter head 41.

[0051] The filter tank is also provided with backwash drainage troughs 16. There are at least two backwash drainage troughs 16, which are respectively arranged on the walls on both sides of the baffle plate 2. The sewage after backwashing is discharged through the backwash drainage trough 8. There is one backwash drainage trough 16 respectively arranged in the first filtration unit 3 and the second filtration unit 4, and they are arranged at the same height. The sewage after backwashing in the first filtration unit 3 and the second filtration unit 4 is discharged through the backwash drainage troughs 16 in their respective units, avoiding the re-pollution of the packing and the filter tank by the flow of sewage between the first filtration unit 3 and the second filtration unit 4.

[0052] The upper edge of the backwash drainage trough 16 is lower than the upper edges of the water inlet trough 6 and the water outlet trough 7; the lower edge of the backwash drainage trough 16 is higher than the packing layer 8. The position of the drainage trough is appropriate, the packing can be fully washed, and the wastewater after backwashing will not enter the water inlet trough 6 and the water outlet trough 7, resulting in the retention of pollutants.

[0053] Gate valves 17 are installed on the water inlet trough 6, the water outlet trough 7 and the backwash drainage trough 16. Preferably, the gate valve 17 is an electric square gate valve. When backwashing, the electric square gate valves of the water inlet trough 6 and the water outlet trough 7 are closed; the electric square gate valve of the backwash drainage trough 16 is opened for flushing.

[0054] The filter tanks are connected in parallel in two or more groups. According to the nitrogen load of the upstream incoming water, the high-efficiency biological heterotrophic and autotrophic coupled denitrification filter tanks need to be used in parallel in two or more groups under the continuous flow state. Each group of reactors takes turns to carry out backwashing so as to maintain continuous inflow and outflow of water when one group of filter tanks is being backwashed.

[0055] When treating wastewater, the wastewater enters each inlet water tank through an electric square gate and is evenly distributed into the first filtration unit 3 through the inlet water tank 6 and then flows downward into the packing layer 8 of the first filtration unit 3; the packing layer 8 of the first filtration unit 3 is composed of heterotrophic and autotrophic coupled packing containing sulfur, iron, calcium and carbonate; among them, the proportion of particles with a particle size of 2-3 mm is 30%-60%, and the proportion of particles with a particle size of 4-6 mm is 40%-70%; the packing layer 8 is supported by a filter plate 9, and long-stem filter nozzles 10 are evenly distributed on the filter plate 9; the wastewater treated by the first filtration unit 3 enters the second filtration unit 4 through the first water hole 5. The second filtration unit 4 is an upflow type, and the wastewater enters the packing layer 8 of the second filtration unit 4 through the long-stem filter nozzles 10. The packing of the packing layer 8 of the second filtration unit 4 is similar to that of the first filtration unit 3, and the proportion of the coupled phosphorus removal packing is appropriately increased; the proportion of the packing with a particle size of 2-3 mm does not exceed 15%, and the rest is filled with the packing with a particle size of 4-6 mm; the wastewater treated by the second filtration unit 4 enters the subsequent process through the outlet water tank 7, and an electric square gate is arranged at the end of the outlet water tank 7. Backwashing is carried out on the filter tanks, and each group of reactors takes turns to carry out backwashing. When backwashing, the electric square gate of the inlet water tank 6 is closed, and the electric square gate of the outlet water tank 7 is closed; the electric square gate of the backwashing drain tank 16 is opened. Backwashing can be carried out by gas alone, backwashing with circulating water alone, and combined gas-water backwashing. The backwashing time is not less than 15 minutes. The backwashing gas enters the packing layer 8 through the blower, the backwashing gas pipe 14 and the long-stem filter nozzles 10, and the backwashing water enters the packing layer 8 through the backwashing water pipe 15 and the long-stem filter nozzles 41; the sewage after backwashing is discharged through the backwashing drain tank 16.

[0056] Taking the treatment of aquaculture wastewater as an example, the changes in the total nitrogen content in the wastewater before the filter tank is used, during commissioning and after stable operation are as Figure 4 shown.

[0057] It can be known that before using the filter tank of the present utility model, the total nitrogen in the aquaculture wastewater is more than 50 mg / L, and the total nitrogen content in the discharged wastewater is basically not reduced much. After being treated with the filter tank of the present utility model, during the commissioning stage, the total nitrogen in the wastewater is reduced to less than 20 mg / L. After the filter tank of the present utility model operates stably, the total nitrogen content in the discharged wastewater is stabilized at a lower level, which is completely lower than the national discharge standard for aquaculture wastewater.

[0058] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0059] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0060] As described above, the above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application can easily think of various changes or substitutions, and these should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A side-flow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter, characterized in that: The filter tank comprises a filter tank body (1) and a baffle (2). The baffle (2) divides the filter tank into a first downflow filter unit (3) and a second upflow filter unit (4); the first filter unit (3) and the second filter unit (4) are connected via a first water passage hole (5) arranged at the bottom of the baffle (2); The filter tank body (1) is provided with a water inlet groove (6) on the upper part of the side wall of the first filter unit (3), and a water outlet groove (7) on the upper part of the side wall of the second filter unit (4); the height of the upper edge of the water outlet groove (7) is lower than the height of the upper edge of the water inlet groove (6); The first filter unit (3) and the second filter unit (4) are provided with a packing layer (8), and the packing layer (8) is a heterotrophic and autotrophic coupled packing.

2. A side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter according to claim 1, characterized in that: The filter tank comprises a filter plate (9), and the filler layer (8) is arranged on the filter plate (9).

3. A side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter according to claim 2, characterized in that: Long-handled filter heads (10) are distributed on the filter plate (9); the gap of the long-handled filter heads (10) is smaller than the particle size of the filler.

4. The side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter according to claim 1, characterized in that: A water inlet channel (11) is also provided outside the filter tank body (1), and the water inlet channel (11) is connected to the water inlet trough (6) through a second water hole (12).

5. The side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter according to claim 1, characterized in that: A backwash pipe (13) is also provided at the bottom of the filter tank, and the backwash pipe (13) comprises a backwash air pipe (14) and a backwash water pipe (15).

6. The side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter according to claim 1, characterized in that: The filter tank is also provided with a backwash drainage groove (16), and there are at least two backwash drainage grooves (16), which are respectively arranged on both sides of the baffle (2); the upper edge of the backwash drainage groove (16) is lower than the upper edge of the water inlet groove (6) and the upper edge of the water outlet groove (7); and the lower edge of the backwash drainage groove (16) is higher than the packing layer (8).

7. The side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter according to claim 1, characterized in that: The water outlet trough (7) is provided with a gate (17).

8. The side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter according to claim 1, characterized in that: The packing layer (8) occupies 20-60% of the volume of the filter unit; The filler layer in the first filter unit (3) is composed of fillers with a particle size of 2-3 mm accounting for 30%-60% and a particle size of 4-6 mm accounting for 40%-70%; The filler layer in the second filter unit (4) is composed of fillers with a particle size of 2-3 mm and a particle size of 4-6 mm, wherein the fillers with a particle size of 2-3 mm account for no more than 15%.

9. The side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter according to claim 1, characterized in that: The filter tanks are connected in parallel in two or more groups.

10. The side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter according to claim 4, characterized in that: The second water passage hole (12) is provided with a gate (17).

11. The side-inflow high-efficiency biological heterotrophic and autotrophic coupled denitrification filter according to claim 6, characterized in that: The backwash drainage trough (16) is equipped with a gate (17).

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