Method and device for high-efficiency denitrification of biogas slurry through anaerobic ammonia oxidation coupling deep denitrification

Abstract

The device comprises a pretreatment unit and a PLC (Programmable Logic Controller), a denitrification reaction unit is arranged on one side of the pretreatment unit, and a deep denitrification unit is arranged on one side of the denitrification reaction unit. Biogas slurry is flocculated through the flocculation tank, flocculate can be subjected to static settlement through the settling tank, so that part of SS and COD is removed, the biogas slurry sequentially passes through the three-phase separator, the carrier and activated sludge to react, primary denitrification is achieved, the denitrified biogas slurry can circulate in the reaction tank through cooperation of the spray header and the transmission unit, and the denitrification effect is improved. The biogas slurry is fully reacted through the composite filler, so that deep denitrification is achieved, by adopting the activated sludge required by anaerobic ammonia oxidation, the carrier adsorbed with the denitrification biological strain and the composite filler, low-carbon-nitrogen-ratio wastewater can be denitrified under the condition that a carbon source does not need to be added, so that the project wastewater can be discharged up to the standard, and the wastewater can be recycled. And the operation cost of wastewater treatment can be saved.

Description

Technical Field

[0001] The present invention relates to the technical field of biogas slurry denitrification, and specifically to a method and device for efficient denitrification of biogas slurry by coupling anaerobic ammonium oxidation and deep denitrification. Background Art

[0002] The water content of kitchen waste is about 87%, so a large amount of kitchen waste wastewater will be generated during the treatment process of kitchen waste. The pollutants in biogas slurry from kitchen waste have high concentration, complex composition and high ammonia nitrogen content, and belong to high-concentration organic wastewater with great treatment difficulty.

[0003] Nitrogen pollution is one of the important pollution problems faced by mankind. The main harms of nitrogen pollution are as follows: First, the harm to water bodies: water eutrophication; Second, the harm to aquatic animals: water eutrophication causes a rapid decrease in dissolved oxygen in water bodies, and a large number of aquatic animals will die due to lack of oxygen; Third, the impact on human ecological health: when water bodies are polluted by nitrogen-containing organic matter, harmful by-products to the human body will be generated during the disinfection of drinking water. Therefore, the removal of nitrogen is an important issue faced by current water treatment.

[0004] At present, the technologies for biogas slurry denitrification are divided into three categories according to the reaction principle: physical technology, chemical technology and biological technology. The biological method is generally considered to be the most economical and effective method. However, for sewage with a low carbon-nitrogen ratio like biogas slurry, a large amount of organic carbon source needs to be added to achieve the removal of total nitrogen, resulting in the generation of a large amount of excess sludge, thus leading to high operating costs.

[0005] Therefore, we propose a method and device for efficient denitrification of biogas slurry by coupling anaerobic ammonium oxidation and deep denitrification to solve this problem. Summary of the Invention

[0006] The purpose of the present invention is to provide a method and device for efficient denitrification of biogas slurry by coupling anaerobic ammonium oxidation and deep denitrification, which have the advantages of cost saving and high removal rate, and solve the problem that the technologies for biogas slurry denitrification are divided into three categories according to the reaction principle: physical technology, chemical technology and biological technology. The biological method is generally considered to be the most economical and effective method. However, for sewage with a low carbon-nitrogen ratio like biogas slurry, a large amount of organic carbon source needs to be added to achieve the removal of total nitrogen, resulting in the generation of a large amount of excess sludge, thus leading to high operating costs.

[0007] To achieve the above object, the present invention provides the following technical solution: A device for anaerobic ammonium oxidation coupled with deep denitrification for efficient denitrification of biogas slurry, comprising a pretreatment unit and a PLC controller. A denitrification reaction unit is provided on one side of the pretreatment unit, and a deep denitrification unit is provided on one side of the denitrification reaction unit. A transmission unit is provided between the pretreatment unit, the denitrification reaction unit and the deep denitrification unit. The pretreatment unit includes a flocculation tank. A sedimentation tank is provided on one side of the flocculation tank, and a first transfer pump is provided between the sedimentation tank and the flocculation tank. The inlet end and the outlet end of the first transfer pump are respectively communicated with the flocculation tank and the sedimentation tank. The denitrification reaction unit includes an anaerobic ammonium oxidation reactor, and a three-phase separator is provided at the upper end of the inner cavity of the anaerobic ammonium oxidation reactor. Activated sludge required for anaerobic ammonium oxidation is provided at the lower end of the inner cavity of the anaerobic ammonium oxidation reactor. A carrier adsorbed with denitrifying biological strains is provided between the activated sludge and the three-phase separator. The upper end of one side of the anaerobic ammonium oxidation reactor is communicated with a transfer pipe. The deep denitrification unit includes a reaction tank. A spray head is provided at the upper end of the inner cavity of the reaction tank, and one end of the transfer pipe is communicated with the spray head. A composite filler is provided at the lower end of the inner cavity of the reaction tank. A gas pump is provided on one side of the denitrification reaction unit. The outlet end of the gas pump is communicated with a three-way pipe, and the other two ends of the three-way pipe are respectively communicated with the anaerobic ammonium oxidation reactor and the reaction tank.

[0008] Preferably, the carrier is a Raschig ring, a cascade ring or a Pall ring, the composite filler is a composite of calcium carbonate and sulfur, and is loaded with denitrifying bacteria.

[0009] Preferably, the top of the flocculation tank is movably connected with a cover, and a liquid injection hopper is communicated with the top of the cover. A motor is fixedly connected to the top of the cover, and an output shaft of the motor is in transmission connection with a stirring paddle. The stirring paddle extends into the inner cavity of the flocculation tank and is movably connected with the inner cavity of the flocculation tank.

[0010] Preferably, a discharge hopper is communicated with the bottom of the sedimentation tank, a first solenoid valve is communicated with the surface of the discharge hopper, a discharge pipe is communicated with one side of the reaction tank, and a second solenoid valve is communicated with the surface of the discharge pipe.

[0011] Preferably, a pH meter and a dissolved oxygen meter are provided inside both the anaerobic ammonium oxidation reactor and the reaction tank, and the output ends of the pH meter and the dissolved oxygen meter are electrically connected to the input end of the PLC controller.

[0012] Preferably, the transfer unit includes a second transfer pump, a first reflux pump and a second reflux pump. The water inlet end of the second transfer pump is communicated with the sedimentation tank, the water outlet end of the second transfer pump is communicated with the anaerobic ammonium oxidation reactor. The water inlet end of the first reflux pump is communicated with the upper end on one side of the anaerobic ammonium oxidation reactor, and the water outlet end of the first reflux pump is communicated with the lower end on one side of the anaerobic ammonium oxidation reactor. The water inlet end of the second reflux pump is communicated with the lower end on one side of the reaction tank, and the water outlet end of the second reflux pump is communicated with the transfer pipe. The input ends of the motor, the first solenoid valve and the second solenoid valve are all electrically connected to the output end of the PLC controller. The output end of the PLC controller is electrically connected to the input ends of the first transfer pump, the second transfer pump, the first reflux pump and the second reflux pump respectively.

[0013] Preferably, the method for efficient denitrification of biogas slurry includes the following steps:

[0014] S1. First, fill the activated sludge containing anaerobic ammonium oxidation bacteria and the carrier loaded with anaerobic ammonium oxidation bacteria into the anaerobic ammonium oxidation reactor, and then load the denitrifying bacteria onto the composite filler to complete the preparation work;

[0015] S2. Pretreatment of biogas slurry:

[0016] S2. First, the biogas slurry enters the flocculation tank through the liquid injection hopper. Immediately afterwards, a flocculant is injected into the flocculation tank through the liquid injection hopper, so that the flocculant flocculates the impurities in the biogas slurry. At the same time, the motor is started through the PLC controller. The output shaft of the motor drives the stirring paddle to rotate, and the stirring paddle drives the biogas slurry and the flocculant to rotate, so that they are fully mixed and quickly flocculated, accelerating the flocculation efficiency;

[0017] S3. After flocculation, the first transfer pump is started through the PLC controller. The first transfer pump transfers the flocculated biogas slurry to the inner cavity of the sedimentation tank. Through the static settlement of the biogas slurry in the inner cavity of the sedimentation tank, the flocculants and sludge in the biogas slurry can fall and settle, realizing solid-liquid separation;

[0018] S4. Reaction denitrification treatment: First, the second transfer pump, the first reflux pump and the air pump are started through the PLC controller. The second transfer pump transfers the liquid in the sedimentation tank to the inner cavity of the anaerobic ammonium oxidation reactor. At the same time, the air pump injects gas into the anaerobic ammonium oxidation reactor, and the first reflux pump can circulate the liquid in the anaerobic ammonium oxidation reactor. Then the liquid will pass through the three-phase separator, the carrier and the activated sludge for reaction frequently, so as to gradually realize the denitrification treatment of the liquid. During the denitrification process, the liquid is monitored in real time by a pH meter and a dissolved oxygen meter, and the monitoring data is transmitted to the PLC controller for analysis until the liquid meets the transfer standard to realize the next transfer;

[0019] S. Advanced denitrification treatment: The liquid after preliminary denitrification treatment will gradually overflow upward inside the anaerobic ammonium oxidation reactor. The liquid can be transported to the inner cavity of the spray head through the transfer pipe, and the spray head, in cooperation with the second reflux pump, can realize the circulating flow of the liquid inside the reaction tank, making the liquid pass through the composite filler frequently. Through the reaction of the liquid with the composite filler, during the reaction process, the liquid is monitored in real time by a pH meter and a dissolved oxygen meter, and the monitoring data is transmitted to the PLC controller for analysis. Until the liquid reaches the discharge standard, the PLC controller can open the second solenoid valve, and the biogas slurry will be discharged through the drain pipe, thereby realizing the advanced denitrification of the biogas slurry.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] In the present invention, the biogas slurry is flocculated through the flocculation tank, and at the same time, the first transfer pump can transfer the flocculated biogas slurry to the inside of the sedimentation tank. Through the sedimentation tank, the flocculated impurities can be statically precipitated, thereby removing part of SS and COD. The biogas slurry reacts successively through the three-phase separator, the carrier, and the activated sludge, and gas is injected into the anaerobic ammonium oxidation reactor through an air pump. The gas and the biogas slurry circulate inside the anaerobic ammonium oxidation reactor through the transfer unit, making them react fully. After denitrification, the biogas slurry overflows upward, and the overflowed biogas slurry can enter the inside of the spray head through the transfer pipe. The spray head, in cooperation with the transfer unit, can make the biogas slurry circulate inside the reaction tank, making the biogas slurry fully react with the composite filler, thereby achieving advanced denitrification and making it reach the standard for discharging into the pipe. By using the activated sludge required for anaerobic ammonium oxidation, the carrier adsorbed with denitrifying biological strains, and the composite filler, the wastewater with a low carbon-nitrogen ratio can be denitrified without adding a carbon source. In this way, not only can the wastewater of the project meet the discharge standard, but also the operating cost of wastewater treatment can be saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of the present invention;

[0023] Figure 2 is a schematic structural diagram of the reaction tank of the present invention;

[0024] Figure 3 is a schematic sectional view of the flocculation tank of the present invention;

[0025] Figure 4 is a schematic partial sectional view of the anaerobic ammonium oxidation reactor of the present invention;

[0026] Figure 5 is a schematic diagram of the system principle of the present invention.

[0027] In the figure: 1. Pretreatment unit; 11. Flocculation tank; 111. Cover; 112. Liquid injection hopper; 113. Motor; 114. Stirring paddle; 12. Sedimentation tank; 121. Discharge hopper; 122. First solenoid valve; 13. First transfer pump; 2. Denitrification reaction unit; 21. Anaerobic ammonium oxidation reactor; 22. Three-phase separator; 23. Carrier; 24. Activated sludge; 25. Transfer pipe; 3. Deep denitrification unit; 31. Reaction tank; 311. Drain pipe; 312. Second solenoid valve; 32. Composite filler; 33. Spray head; 4. Transfer unit; 41. Second transfer pump; 42. First reflux pump; 43. Second reflux pump; 5. PLC controller; 6. Air pump. Detailed implementation manners

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] The components of the pretreatment unit 1, flocculation tank 11, cover 111, liquid injection hopper 112, motor 113, stirring paddle 114, sedimentation tank 12, discharge hopper 121, first solenoid valve 122, first transfer pump 13, denitrification reaction unit 2, anaerobic ammonium oxidation reactor 21, three-phase separator 22, carrier 23, activated sludge 24, deep denitrification unit 3, reaction tank 31, composite filler 32, spray head 33, transfer unit 4, second transfer pump 41, first reflux pump 42 and second reflux pump 43 of the present invention are all common standard components or components known to those skilled in the art, and their structures and principles can all be known by those skilled in the art through technical manuals or obtained through conventional experimental methods.

[0030] Embodiment 1

[0031] As Figures 1-5As shown in the figure, this is the first embodiment of the present invention. This embodiment provides a device for anaerobic ammonium oxidation coupled with deep denitrification for efficient denitrification of biogas slurry, including a pretreatment unit 1 and a PLC controller 5. A denitrification reaction unit 2 is arranged on one side of the pretreatment unit 1, and a deep denitrification unit 3 is arranged on one side of the denitrification reaction unit 2. A transmission unit 4 is arranged between the pretreatment unit 1, the denitrification reaction unit 2 and the deep denitrification unit 3. The pretreatment unit 1 includes a flocculation tank 11. A sedimentation tank 12 is arranged on one side of the flocculation tank 11, and a first transfer pump 13 is arranged between the sedimentation tank 12 and the flocculation tank 11. The inlet end and the outlet end of the first transfer pump 13 are respectively communicated with the flocculation tank 11 and the sedimentation tank 12. The denitrification reaction unit 2 includes an anaerobic ammonium oxidation reactor 21, and a three-phase separator 22 is arranged at the upper end of the inner cavity of the anaerobic ammonium oxidation reactor 21. Anaerobic ammonium oxidation required activated sludge 24 is arranged at the lower end of the inner cavity of the anaerobic ammonium oxidation reactor 21. A carrier 23 adsorbed with denitrifying biological strains is arranged between the activated sludge 24 and the three-phase separator 22. The upper end of one side of the anaerobic ammonium oxidation reactor 21 is communicated with a transfer pipe 25. The deep denitrification unit 3 includes a reaction tank 31. A spray head 33 is arranged at the upper end of the inner cavity of the reaction tank 31, and one end of the transfer pipe 25 is communicated with the spray head 33. Composite packing 32 is arranged at the lower end of the inner cavity of the reaction tank 31. A gas pump 6 is arranged on one side of the denitrification reaction unit 2. The outlet end of the gas pump 6 is communicated with a three-way pipe, and the other two ends of the three-way pipe are respectively communicated with the anaerobic ammonium oxidation reactor 21 and the reaction tank 31.

[0032] The carrier 23 is a Raschig ring, a cascade ring or a Pall ring. The composite packing 32 is a composite substance of calcium carbonate and sulfur and is loaded with denitrifying bacteria.

[0033] As Figures 1-5 As shown in the figure, the biogas slurry is flocculated by the flocculation tank 11. At the same time, the first transfer pump 13 can transfer the flocculated biogas slurry into the sedimentation tank 12. The flocculated impurities can be statically precipitated by the sedimentation tank 12 to remove part of SS and COD. The biogas slurry reacts successively through the three-phase separator 22, the carrier 23 and the activated sludge 24. And gas is injected into the anaerobic ammonium oxidation reactor 21 by the gas pump 6. The gas and the biogas slurry are circulated inside the anaerobic ammonium oxidation reactor 21 through the transmission of the transmission unit 4 to make them fully react. After denitrification, the biogas slurry overflows upward. The overflowed biogas slurry can enter the spray head 33 through the transfer pipe 25. The spray head 33 cooperates with the transmission unit 4 to make the biogas slurry circulate inside the reaction tank 31, so that the biogas slurry fully reacts with the composite packing 32 to achieve deep denitrification and reach the standard for discharging into the pipe network. By using the activated sludge 24 required for anaerobic ammonium oxidation, the carrier 23 adsorbed with denitrifying biological strains and the composite packing 32, the low carbon-nitrogen ratio wastewater can be denitrified without adding a carbon source. In this way, not only can the project wastewater meet the discharge standards, but also the operating cost of wastewater treatment can be saved.

[0034] Example 2

[0035] Reference Figure 3 , which is the second embodiment of the present invention, and this embodiment is based on the previous embodiment.

[0036] In this embodiment, a cover 111 is movably connected to the top of the flocculation tank 11, and a liquid injection hopper 112 is communicated with the top of the cover 111. A motor 113 is fixedly connected to the top of the cover 111, and an output shaft of the motor 113 is drivingly connected to a stirring paddle 114. The stirring paddle 114 extends into the inner cavity of the flocculation tank 11 and is movably connected to the inner cavity of the flocculation tank 11.

[0037] A discharge hopper 121 is communicated with the bottom of the sedimentation tank 12, a first electromagnetic valve 122 is communicated with the surface of the discharge hopper 121, a liquid discharge pipe 311 is communicated with one side of the reaction tank 31, and a second electromagnetic valve 312 is communicated with the surface of the liquid discharge pipe 311.

[0038] As Figure 3 shown, the flocculation tank 11 can be closed through the cover 111, and the liquid injection hopper 112 is convenient for transmitting biogas slurry and flocculant into the flocculation tank 11. At the same time, the output shaft of the motor 113 can drive the stirring paddle 114 to rotate, thereby facilitating the reaction effect of biogas slurry and flocculant. By opening the first electromagnetic valve 122, the sludge and flocculants inside the sedimentation tank 12 can be discharged through the discharge hopper 121. By opening the second electromagnetic valve 312, the biogas slurry inside the reaction tank 31 can be discharged through the liquid discharge pipe 311.

[0039] Example 3

[0040] Reference Figure 1 and 5 , which is the third embodiment of the present invention, and this embodiment is based on the previous two embodiments.

[0041] In this embodiment, pH meters and dissolved oxygen meters are arranged inside both the anaerobic ammonium oxidation reactor 21 and the reaction tank 31, and the output ends of the pH meters and the dissolved oxygen meters are electrically connected to the input end of the PLC controller 5.

[0042] The transfer unit 4 includes a second transfer pump 41, a first reflux pump 42 and a second reflux pump 43. The water inlet end of the second transfer pump 41 is communicated with the sedimentation tank 12, and the water outlet end of the second transfer pump 41 is communicated with the anaerobic ammonium oxidation reactor 21. The water inlet end of the first reflux pump 42 is communicated with the upper end on one side of the anaerobic ammonium oxidation reactor 21, and the water outlet end of the first reflux pump 42 is communicated with the lower end on one side of the anaerobic ammonium oxidation reactor 21. The water inlet end of the second reflux pump 43 is communicated with the lower end on one side of the reaction tank 31, and the water outlet end of the second reflux pump 43 is communicated with the transfer pipe 25. The input ends of the motor 113, the first solenoid valve 122 and the second solenoid valve 312 are all electrically connected to the output end of the PLC controller 5. The output end of the PLC controller 5 is respectively electrically connected to the input ends of the first transfer pump 13, the second transfer pump 41, the first reflux pump 42 and the second reflux pump 43.

[0043] As Figure 1 and 5 shown, the biogas slurry inside the sedimentation tank 12 can be transferred to the inside of the anaerobic ammonium oxidation reactor 21 through the second transfer pump 41 for reaction. The self-circulation flow of the biogas slurry inside the anaerobic ammonium oxidation reactor 21 can be realized through the first reflux pump 42, which speeds up the reaction efficiency. At the same time, the self-circulation flow of the biogas slurry inside the reaction tank 31 can be realized through the second reflux pump 43, which speeds up the reaction efficiency and enables rapid denitrification.

[0044] A method for efficient denitrification of biogas slurry by anaerobic ammonium oxidation coupling deep denitrification, the method for efficient denitrification of biogas slurry includes the following steps:

[0045] S1. First, the activated sludge 24 containing anaerobic ammonium oxidation bacteria and the carrier 23 loaded with anaerobic ammonium oxidation bacteria are filled into the anaerobic ammonium oxidation reactor 21, and then the denitrifying bacteria are loaded on the composite filler 32 to complete the preparation work;

[0046] S2. Biogas slurry pretreatment:

[0047] S21. First, the biogas slurry enters the inside of the flocculation tank 11 through the liquid injection hopper 112. Immediately afterwards, a flocculant is injected into the inside of the flocculation tank 11 through the liquid injection hopper 112, so that the flocculant flocculates the impurities in the biogas slurry. At the same time, the motor 113 is started through the PLC controller 5. The output shaft of the motor 113 drives the stirring paddle 114 to rotate, and the stirring paddle 114 drives the biogas slurry and the flocculant to rotate, so that they are fully mixed and rapidly flocculated, accelerating the flocculation efficiency;

[0048] S22. After flocculation, the first transfer pump 13 is started through the PLC controller 5. The first transfer pump 13 transfers the flocculated biogas slurry to the inner cavity of the sedimentation tank 12. Through the static settlement of the biogas slurry in the inner cavity of the sedimentation tank 12, the flocculants and sludge in the biogas slurry can fall and settle, realizing solid-liquid separation;

[0049] S3. Denitrification treatment by reaction: First, the PLC controller 5 is used to turn on the second transfer pump 41, the first reflux pump 42 and the air pump 6. The liquid inside the sedimentation tank 12 is transferred to the inner cavity of the anammox reactor 21 through the second transfer pump 41. Meanwhile, the air pump 6 injects gas into the anammox reactor 21, and the first reflux pump 42 can circulate the liquid inside the anammox reactor 21. Thus, the liquid will frequently pass through the three-phase separator 22, the carrier 23 and the activated sludge 24 for reaction, so as to gradually achieve denitrification treatment of the liquid. During the denitrification process, the liquid is monitored in real time by a pH meter and a dissolved oxygen meter, and the monitoring data is transmitted to the PLC controller 5 for analysis until the liquid meets the transfer standard to enable the next transfer;

[0050] S4. Deep denitrification treatment: The liquid after preliminary denitrification treatment will gradually overflow upward inside the anammox reactor 21. The liquid can be transferred to the inner cavity of the spray head 33 through the transfer pipe 25, and the spray head 33 and the second reflux pump 43 cooperate to achieve the circulation of the liquid inside the reaction tank 31, so that the liquid frequently passes through the composite filler 32. The liquid reacts through the composite filler 32. During the reaction process, the liquid is monitored in real time by a pH meter and a dissolved oxygen meter, and the monitoring data is transmitted to the PLC controller 5 for analysis. Until the liquid meets the discharge standard, the PLC controller 5 can turn on the second solenoid valve 312, and the biogas slurry will be discharged through the drain pipe 311, so as to achieve deep denitrification of the biogas slurry.

[0051] The standard parts used in this application document can all be purchased from the market, and can also be customized according to the description in the specification and the drawings. The specific connection methods of each part all adopt conventional means such as bolts, rivets, welding, etc. that are mature in the prior art. The machinery, parts and equipment all adopt conventional models in the prior art. The control method is automatically controlled by a controller. The control circuit of the controller can be realized by simple programming by those skilled in the art, which belongs to the common general knowledge in this field. And this application document is mainly used to protect the mechanical device, so the control method and the circuit connection are not explained in detail in this application document.

[0052] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0053] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An anaerobic ammonium oxidation coupled with deep denitrification device for efficient nitrogen removal from biogas slurry, comprising a pretreatment unit (1) and a PLC controller (5), characterized in that: On one side of the pretreatment unit (1), a denitrification reaction unit (2) is arranged, and on one side of the denitrification reaction unit (2), a deep denitrification unit (3) is arranged. A transmission unit (4) is arranged between the pretreatment unit (1), the denitrification reaction unit (2) and the deep denitrification unit (3). The pretreatment unit (1) includes a flocculation tank (11). On one side of the flocculation tank (11), a sedimentation tank (12) is arranged. A first transfer pump (13) is arranged between the sedimentation tank (12) and the flocculation tank (11). The inlet end and the outlet end of the first transfer pump (13) are respectively communicated with the flocculation tank (11) and the sedimentation tank (12). The denitrification reaction unit (2) includes an anaerobic ammonium oxidation reactor (21). At the upper end of the inner cavity of the anaerobic ammonium oxidation reactor (21), a three-phase separator (22) is arranged. At the lower end of the inner cavity of the anaerobic ammonium oxidation reactor (21), activated sludge (24) required for anaerobic ammonium oxidation is arranged. A carrier (23) adsorbed with denitrifying biological strains is arranged between the activated sludge (24) and the three-phase separator (22). The upper end of one side of the anaerobic ammonium oxidation reactor (21) is communicated with a transfer pipe (25). The deep denitrification unit (3) includes a reaction tank (31). At the upper end of the inner cavity of the reaction tank (31), a spray head (33) is arranged. One end of the transfer pipe (25) is communicated with the spray head (33). At the lower end of the inner cavity of the reaction tank (31), a composite filler (32) is arranged. On one side of the denitrification reaction unit (2), an air pump (6) is arranged. The air outlet end of the air pump (6) is communicated with a three-way pipe, and the other two ends of the three-way pipe are respectively communicated with the anaerobic ammonium oxidation reactor (21) and the reaction tank (31).

2. The device for efficient nitrogen removal from biogas slurry by anaerobic ammonium oxidation coupled with deep nitrogen removal according to claim 1, characterized in that: The carrier (23) is a Raschig ring, a cascade ring or a Pall ring. The composite filler (32) is a composite substance of calcium carbonate and sulfur and is loaded with denitrifying bacteria.

3. An apparatus for highly efficient nitrogen removal from biogas slurry by anaerobic ammonium oxidation coupled with deep nitrogen removal according to claim 1, characterized in that: The top of the flocculation tank (11) is movably connected with a cover (111). The top of the cover (111) is communicated with a liquid injection hopper (112). The top of the cover (111) is fixedly connected with a motor (113). The output shaft of the motor (113) is drivingly connected with a stirring paddle (114). The stirring paddle (114) extends into the inner cavity of the flocculation tank (11) and is movably connected with the inner cavity of the flocculation tank (11).

4. An apparatus for efficient nitrogen removal from biogas slurry by anaerobic ammonium oxidation coupled with deep denitrification according to claim 3, characterized in that: The bottom of the sedimentation tank (12) is communicated with a discharge hopper (121). The surface of the discharge hopper (121) is communicated with a first electromagnetic valve (122). One side of the reaction tank (31) is communicated with a drain pipe (311). The surface of the drain pipe (311) is communicated with a second electromagnetic valve (312).

5. An apparatus for anaerobic ammonium oxidation coupled with deep denitrification for efficient denitrification of biogas slurry according to claim 1, characterized in that: pH meters and dissolved oxygen meters are arranged inside both the anaerobic ammonium oxidation reactor (21) and the reaction tank (31), and the output ends of the pH meters and the dissolved oxygen meters are electrically connected with the input end of a PLC controller (5).

6. The device for efficient nitrogen removal from biogas slurry by anaerobic ammonium oxidation coupled with deep denitrification according to claim 4, wherein: The transmission unit (4) includes a second transfer pump (41), a first reflux pump (42) and a second reflux pump (43). The water inlet end of the second transfer pump (41) is communicated with the sedimentation tank (12), and the water outlet end of the second transfer pump (41) is communicated with the anammox reactor (21). The water inlet end of the first reflux pump (42) is communicated with the upper end on one side of the anammox reactor (21), and the water outlet end of the first reflux pump (42) is communicated with the lower end on one side of the anammox reactor (21). The water inlet end of the second reflux pump (43) is communicated with the lower end on one side of the reaction tank (31), and the water outlet end of the second reflux pump (43) is communicated with the transfer pipe (25). The input ends of the motor (113), the first solenoid valve (122) and the second solenoid valve (312) are all electrically connected to the output end of the PLC controller (5). The output end of the PLC controller (5) is respectively electrically connected to the input ends of the first transfer pump (13), the second transfer pump (41), the first reflux pump (42) and the second reflux pump (43).

7. A method for anaerobic ammonium oxidation coupled with deep denitrification for efficient denitrification of biogas slurry according to any one of claims 1-6, characterized in that: The method for efficient nitrogen removal from biogas slurry includes the following steps: S1. First, fill the activated sludge (24) containing anammox bacteria and the carrier (23) loaded with anammox bacteria into the anammox reactor (21), and then load the denitrifying bacteria onto the composite filler (32) to complete the preparation work; S2. Pretreatment of biogas slurry: S21. First, the biogas slurry enters the flocculation tank (11) through the liquid injection hopper (112). Immediately afterwards, a flocculant is injected into the flocculation tank (11) through the liquid injection hopper (112) to perform a flocculation operation on the impurities in the biogas slurry. At the same time, the motor (113) is turned on through the PLC controller (5). The output shaft of the motor (113) drives the stirring paddle (114) to rotate, and the stirring paddle (114) drives the biogas slurry and the flocculant to rotate, so that they are fully mixed and quickly flocculated, accelerating the flocculation efficiency; S22. After flocculation, the first transfer pump (13) is turned on through the PLC controller (5). The first transfer pump (13) transfers the flocculated biogas slurry to the inner cavity of the sedimentation tank (12). By allowing the biogas slurry to stand still in the inner cavity of the sedimentation tank (12), the flocculants and sludge in the biogas slurry can fall and precipitate, realizing solid-liquid separation; S3. Reaction denitrification treatment: First, turn on the second transfer pump (41), the first reflux pump (42) and the air pump (6) through the PLC controller (5). Transfer the liquid inside the sedimentation tank (12) to the inner cavity of the anammox reactor (21) through the second transfer pump (41). At the same time, the air pump (6) injects gas into the inside of the anammox reactor (21), and the first reflux pump (42) can circulate the liquid inside the anammox reactor (21). Then the liquid will frequently pass through the three-phase separator (22), the carrier (23) and the activated sludge (24) for reaction, so as to gradually achieve denitrification treatment of the liquid. During the denitrification process, the liquid is monitored in real time by a pH meter and a dissolved oxygen meter, and the monitoring data is transmitted to the PLC controller (5) for analysis until the liquid meets the transfer standard to achieve the next transfer; S4. Deep denitrification treatment: The liquid after preliminary denitrification treatment will gradually overflow upward inside the anammox reactor (21). The liquid can be transferred to the inner cavity of the spray head (33) through the transfer pipe (25). The spray head (33) and the second reflux pump (43) can realize the circulation of the liquid inside the reaction tank (31), so that the liquid frequently passes through the composite filler (32). The liquid reacts through the composite filler (32). During the reaction process, the liquid is monitored in real time by a pH meter and a dissolved oxygen meter, and the monitoring data is transmitted to the PLC controller (5) for analysis. Until the liquid meets the discharge standard, the second solenoid valve (312) can be turned on through the PLC controller (5), and the biogas slurry will be discharged through the drain pipe (311), so as to achieve deep denitrification of the biogas slurry.

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