An anaerobic fermentation biogas slurry treatment system for fruit and vegetable waste

Abstract

The application discloses a kind of fruit and vegetable garbage anaerobic fermentation biogas slurry processing systems, including grid device, centrifuge, filter press, membrane separation device, deamination device, anaerobic reactor, anaerobic sedimentation tank, biochemical treatment device and coagulation reaction sedimentation tank, effluent of biochemical treatment device is removed total phosphorus, color and part COD in water after coagulation reaction sedimentation tank Cr , treated wastewater is discharged up to standard.The application can effectively remove suspended solids in biogas slurry, realize the resource utilization of organic matter and nitrogen and phosphorus in biogas slurry, and the effluent quality reaches the first A standard in "Municipal Sewage Treatment Plant Pollutant Discharge Standard" (GB18918-2002).

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sewage treatment, and particularly relates to a fruit and vegetable waste anaerobic fermentation biogas slurry treatment system. BACKGROUND

[0002] In China, the field of fruit and vegetable waste treatment, especially the resource-oriented direction, is still in the exploratory stage, and the technical and engineering development accumulation is far less than that of foreign countries. Limited by the level of industry development, there is no mature market for organic fertilizer utilization in China at present, and the fruit and vegetable press liquor or the biogas slurry after fermentation is mostly disposed as sewage.

[0003] The fruit and vegetable waste anaerobic fermentation biogas slurry contains high concentrations of suspended solids, COD, total nitrogen, ammonia nitrogen and total phosphorus, etc., among which the ammonia nitrogen accounts for 50% to 60% of the total nitrogen. The existing treatment technology generally adopts methods such as grating, air flotation and dewatering machine for pretreatment. After pretreatment, the wastewater still contains high solid content, and the organic matter is seriously lost. These organic matters also seriously affect the normal operation of the subsequent anaerobic treatment process and biochemical treatment process. The organic matter in the pretreated wastewater exists in the form of short fibrous suspended solids, and the conventional wastewater anaerobic treatment process has poor removal effect on short fibrous suspended solids, which leads to serious loss of anaerobic sludge, increases the load of the biochemical system, and affects the effluent of the biochemical system and the operation of the MBR membrane.

[0004] Due to the high concentration of total nitrogen in the biogas slurry, the C / N in the biogas slurry is low after pretreatment, and a large amount of carbon source needs to be added for biological denitrification, which increases the operation cost. The biogas slurry and biogas residue after anaerobic fermentation of fruit and vegetable waste are rich in nitrogen, phosphorus, potassium, humic acid, amino acid, microorganism, protein and other components, and can be used as excellent organic fertilizer.

[0005] The fruit and vegetable press liquor or biogas slurry belongs to special sewage with high organic matter concentration, high nitrogen and phosphorus, and high suspended solids, and it is difficult to treat. When the traditional process is adopted, it is difficult to reach the first level A standard in the "Urban Sewage Treatment Plant Pollutant Discharge Standard" (GB18918-2002). SUMMARY

[0006] In order to overcome the shortcomings of the prior art, the present application provides a fruit and vegetable waste anaerobic fermentation biogas slurry treatment system, which realizes the resource utilization of organic matter in the biogas slurry, recovers nitrogen and phosphorus in the biogas slurry, reduces the treatment burden of the subsequent biochemical system, ensures the stable operation of the biochemical treatment system, and makes the final effluent water quality stable to reach the first level A standard in the "Urban Sewage Treatment Plant Pollutant Discharge Standard" (GB18918-2002).

[0007] To achieve the above purpose, the technical solution of the present application is:

[0008] A fruit and vegetable waste anaerobic fermentation biogas slurry treatment system, comprising a grid device, the grid device filters the biogas slurry of the fermentation system and inputs the filtered biogas slurry into a centrifugal machine, and the biogas residue generated by the grid device is input into a biogas fertilizer system;

[0009] The centrifugal machine performs centrifugal treatment on the biogas slurry filtered by the grid, the waste water output by the centrifugal machine is output into a filter press, and the biogas residue generated by the centrifugal machine is output into the biogas fertilizer system;

[0010] The filter press performs filter pressing on the biogas slurry output by the centrifugal machine, the waste water output by the filter press is output into a membrane separation device, and the biogas residue generated by the filter press is output into the biogas fertilizer system;

[0011] The membrane separation device performs membrane separation on the waste water input by the filter press, generates product water and concentrated water, the product water is input into a deamination device, and the concentrated water is input into a fermentation system;

[0012] The deamination device performs denitrification treatment on the product water of the membrane separation device and part of the effluent of an anaerobic sedimentation tank, and the waste water after denitrification treatment is input into an anaerobic reactor;

[0013] The anaerobic reactor performs preliminary COD Cr removal treatment on the waste water, the waste water after preliminary removal of COD Cr is input into the anaerobic sedimentation tank, and the generated biogas is input into a biogas system;

[0014] The anaerobic sedimentation tank performs anaerobic sedimentation on the waste water, part of the effluent is backflowed to the deamination device, the remaining part of the effluent enters a biochemical treatment device, part of the sludge of the anaerobic sedimentation tank is backflowed to the anaerobic reactor, and the remaining part of the sludge is output into a first sludge dewatering system;

[0015] The biochemical treatment device further removes COD Cr , ammonia nitrogen and total nitrogen from the input waste water, the sludge generated by the biochemical treatment device is output into the first sludge dewatering system, and the effluent of the biochemical treatment device is input into a coagulation reaction sedimentation tank,

[0016] The coagulation reaction sedimentation tank further removes total phosphorus, color and COD Cr from the waste water, and the generated sludge is input into a second sludge dewatering system.

[0017] Part of the sludge generated by the first sludge dewatering system is transported into the fermentation system, mixed fermentation is performed with the concentrated water output by the membrane separation device in the fermentation system, the generated biogas slurry is input into the grid device, the generated biogas is input into the biogas system, and the filtrate generated by the first sludge dewatering system is input into the deamination device.

[0018] The sludge generated by the second sludge dewatering system is transported out for treatment, and the filtrate output by the second sludge dewatering system is input into the deamination device.

[0019] The grid device as described above comprises a filtrate pool and a cylindrical screen arranged above the filtrate pool, the input end of the screw conveyor extends into the cylindrical screen, a notch is arranged on the input end shell of the screw conveyor, the notch is connected with the slag collecting groove, the edge of the slag collecting groove is provided with a slag scraping plate extending to the inner wall of the screen, the outer wall of the screen is provided with a slag cleaning device which is stationary relative to the screen, the slag cleaning device comprises a metal brush and a flushing water pipe, one end of the screw conveying rod of the screw conveyor extends out of the input end shell and is connected with the screen through a rotating drum support, one end of the water inlet cover is connected with one end of the water inlet pipe, the water inlet of the water inlet pipe is conveyed to the cylindrical screen through the water inlet cover, the output end of the screw conveyor is provided with a squeezing area connected with the slag outlet, the filtrate pool is connected with the input port of the filtrate lifting pump through a pipeline, the output port of the filtrate lifting pump outputs biogas slurry through a pipeline, and the screw conveying rod of the screw conveyor is driven to rotate by a speed reducer motor.

[0020] The membrane separation device as described above comprises a water inlet tank, a membrane assembly, a cleaning water tank, and a water production tank,

[0021] The water inlet tank is connected with the input end of the membrane device water inlet pump through a pipeline, the output end of the membrane device water inlet pump is connected with the membrane water inlet pipe of the membrane assembly through a membrane device water inlet pipeline, a switch valve is arranged on the membrane device water inlet pipeline, the membrane concentrated water outlet of the membrane assembly is connected with the water inlet tank through a first concentrated water pipeline, a switch valve is arranged on the first concentrated water pipeline, the membrane concentrated water outlet of the membrane assembly is also connected with the cleaning water tank through a second concentrated water pipeline, a switch valve is arranged on the second concentrated water pipeline, the membrane device air compressor is connected with the membrane water inlet pipe of the membrane assembly through a flushing gas pipe, a switch valve is arranged on the flushing gas pipe, the membrane assembly is arranged above the cleaning water tank through a membrane support, the emptying port of the membrane assembly is located above the cleaning water tank, the membrane water outlet of the membrane assembly is connected with the cleaning water tank through a cleaning water production backflow pipe, a switch valve is arranged on the cleaning water production backflow pipe, the membrane water outlet of the membrane assembly is connected with the output port of the cleaning pump through a backwashing water inlet pipe, a switch valve is arranged on the backwashing water inlet pipe, the membrane water outlet of the membrane assembly is connected with the water production tank through a water production pipe, a switch valve is arranged on the water production pipe, the cleaning water tank is connected with the input port of the cleaning pump through a pipeline, and the output port of the cleaning pump is also connected with the membrane water inlet pipe of the membrane assembly through a flushing water inlet pipe, a switch valve is arranged on the flushing water inlet pipe.

[0022] The membrane module comprises a membrane shell, a vertically arranged central pipe arranged in the membrane shell, a bottom end of the central pipe being sealed and connected with a rotating shaft of a membrane deceleration motor through the membrane shell, a membrane water production outlet arranged at a top of the membrane shell, a top end of the central pipe being inserted into the membrane water production outlet and being rotatable relative to the membrane water production outlet, a plurality of membrane sheets arranged along the central pipe, the membrane sheets being disc-shaped and coaxially arranged with the central pipe, a membrane water inlet pipe arranged in the membrane shell, a bottom end of the membrane water inlet pipe being sealed and extended out of the membrane shell, the membrane water inlet pipe being connected with each membrane water inlet branch pipe, water distribution holes being arranged on the membrane water inlet branch pipe, the membrane water inlet branch pipes being arranged between adjacent membrane sheets, an outer surface of the membrane sheet being a filter layer, the membrane sheet containing a spiral-shaped water production channel in an inner portion of the membrane sheet, one end of the water production channel being extended into the filter layer, the other end of the water production channel being communicated with the central pipe, a membrane concentrated water outlet being arranged at an upper portion of the membrane shell, and a venting port being arranged at a bottom of the membrane shell.

[0023] The deaminating device comprises a first reaction tank, a dissolved gas deaminating reactor, an absorption tower, a degassing tank, a second reaction tank, a third reaction tank, a deaminating device sedimentation tank, and a mixing tank,

[0024] The first reaction tank is equipped with an inlet pipe for the ammonia removal device and a first dosing pipe. An aeration unit is located at the bottom of the first reaction tank. The outlet at the bottom of the first reaction tank is connected to the inlet of the dissolved gas ammonia removal reactor via an inlet pump for the ammonia removal device and a jet mixer. The outlet at the top of the first reaction tank is connected to the inlet of an exhaust fan. A guide plate, cylindrical in shape, is installed at the inlet of the dissolved gas ammonia removal reactor. The water inlet direction of the dissolved gas ammonia removal reactor... Tangentially to the guide plate and inclined upwards, the bottom of the dissolved gas deammoniation reactor is equipped with a conical baffle, and the top of the conical baffle is equipped with a dissolved gas release device. An outlet is located below the conical baffle inside the dissolved gas deammoniation reactor. The outlet of the dissolved gas deammoniation reactor is connected to the degassing tank via an outlet pipe. The outlet of the dissolved gas deammoniation reactor is also connected to the dissolved gas inlet of the dissolved gas deammoniation reactor via a dissolved gas pump. The dissolved gas inlet is connected to the dissolved gas release device via a pipeline. The gas outlet at the top of the dissolved gas deammoniation reactor is connected to the exhaust system. The air inlet of the blower is connected to the air outlet at the top of the degassing tank, which is connected to the air inlet of the blower. An aeration unit is installed at the bottom of the degassing tank. The bottom of the degassing tank is connected to the bottom of the second reaction tank. The top of the second reaction tank is connected to the top of the third reaction tank via an overflow connection. The bottom of the third reaction tank is connected to the bottom of the overflow channel. The top of the overflow channel is connected to the inlet pipe of the sedimentation tank of the ammonia removal unit. A second dosing pipe is installed on the second reaction tank, and a third dosing pipe is installed on the third reaction tank. The outlet of the sedimentation tank of the ammonia removal unit... Water pipes are connected to the mixing tank, which is equipped with an anaerobic reflux pipe. The anaerobic reflux pipe is connected to the outlet of the anaerobic sedimentation tank. The outlet at the bottom of the mixing tank is connected to the inlet of the anaerobic inlet pump. The outlet of the anaerobic inlet pump is connected to the inlet of the anaerobic reactor. The aeration units at the bottom of the first reaction tank and the aeration units at the bottom of the degassing tank are both connected to blowers. The outlet of the blower is connected to the absorption tower. A circulating water tank is installed at the bottom of the absorption tower. The circulating water tank is connected to the inlet of the absorption tower through a spray pump.

[0025] As described above, alkali solution is added to the first reaction tank through the first dosing pipe, magnesium chloride solution is added to the second reaction tank through the second dosing pipe, and flocculant is added to the third reaction tank through the third dosing pipe.

[0026] As described above, the biochemical treatment device includes a primary anoxic tank, a primary aerobic tank, a primary membrane tank, a secondary anoxic tank, a secondary aerobic tank, and a secondary membrane tank.

[0027] The primary anoxic tank is provided with a biochemical water inlet pipe and a primary circulation return pipe, the bottom of the primary anoxic tank is communicated with the bottom of the primary aerobic tank, a jet aerator is arranged in the primary anoxic tank, the water outlet of the primary aerobic tank is connected with the water inlet of the primary membrane tank, the circulation water outlet at the bottom of the primary membrane tank is connected with the primary circulation return pipe of the primary anoxic tank through a return pump, the water outlet of the primary MBR membrane in the primary membrane tank is connected with the secondary water inlet pipe arranged on the secondary anoxic tank through a water pump, the secondary anoxic tank is provided with a secondary circulation return pipe, the bottom of the secondary anoxic tank is communicated with the bottom of the secondary aerobic tank, the water outlet of the secondary aerobic tank is connected with the water inlet of the secondary membrane tank, the circulation water outlet at the bottom of the secondary membrane tank is connected with the secondary circulation return pipe of the secondary anoxic tank through a return pump, and the water outlet of the secondary MBR membrane in the secondary membrane tank is connected with the water inlet of the coagulation reaction and sedimentation tank,

[0028] The output ports of the air compressors are connected with the jet aerators in the primary aerobic tank, the jet aerators in the secondary aerobic tank, the aerators below the primary MBR membrane in the primary membrane tank and the aerators below the secondary MBR membrane in the secondary membrane tank respectively,

[0029] The bottom of the primary aerobic tank is connected with the water inlet of the primary aerobic tank water pump, the water outlet of the primary aerobic tank water pump is connected with the jet aerator in the primary aerobic tank through a pipeline, the bottom of the secondary aerobic tank is connected with the water inlet of the secondary aerobic tank water pump, and the water outlet of the secondary aerobic tank water pump is connected with the jet aerator in the secondary aerobic tank through a pipeline.

[0030] The coagulation reaction and sedimentation tank comprises a reaction tank and a sedimentation tank, the reaction tank comprises a first reaction tank, a second reaction tank and a third reaction tank connected in series, the water inlet of the first reaction tank serves as the water inlet of the coagulation reaction and sedimentation tank, the water outlet of the third reaction tank is connected with the sedimentation tank, potassium ferrate or an adsorbent is added in the first reaction tank, polyaluminum chloride or polyaluminum sulfate is added in the second reaction tank, and a flocculating agent is added in the third reaction tank.

[0031] Compared with the prior art, the present application has the following beneficial effects:

[0032] (1) The present application effectively removes the larger fibrous organic matter in the biogas slurry by using the pretreatment process such as the grid, centrifuge and filter press, and effectively removes the small organic matter in the biogas slurry by using the membrane separation device, so as to solve the problems of sludge loss of anaerobic effluent, unstable water quality of biochemical system effluent and MBR membrane pollution caused by short fiber suspended matter in the biogas slurry. In the process of removing the organic matter by the membrane separation device, the organic matter in the biogas slurry can be effectively recovered, the resource recovery efficiency is improved, the organic nitrogen in the total nitrogen can be effectively removed, the denitrification load of the subsequent biochemical treatment system is reduced, the carbon source is saved, and the energy consumption is reduced.

[0033] (2) The present application further removes ammonia nitrogen in wastewater by using a deamination device, recovers total phosphorus in wastewater, realizes resource recycling of nitrogen and phosphorus in biogas liquid, reduces the treatment load of subsequent biochemical treatment system, saves carbon source and reduces energy consumption.

[0034] (3) The present application effectively removes COD in wastewater by using an anaerobic and two-stage AO combined process (biochemical treatment device), converts COD in wastewater into biogas by anaerobic treatment, ensures C / N in the influent of the two-stage AO system, realizes the maximum utilization of COD in wastewater, and improves the resource utilization efficiency of biogas liquid. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a structural schematic diagram of the present application.

[0036] Figure 2 is a structural schematic diagram of the grid device.

[0037] Figure 3 is a structural schematic diagram of the screen part of the grid device.

[0038] Figure 4 is a structural schematic diagram of the membrane separation device.

[0039] Figure 5 is a structural schematic diagram of the deamination device.

[0040] Figure 6 is a structural schematic diagram of the biochemical treatment device.

[0041] In the figure: 1 - water inlet pipe; 2 - water inlet cover; 3 - screen; 4 - screw conveyor; 5 - squeezing area; 6 - slag outlet; 7 - speed reducer motor; 8 - slag removal device; 9 - mounting bracket; 10 - filtrate tank; 11 - filtrate lifting pump; 12 - drum support; 13 - slag collecting groove; 14 - slag scraping plate; 21 - water inlet tank; 22 - membrane device water inlet pump; 23 - membrane device air compressor; 24 - membrane housing; 25 - membrane water inlet pipe; 26 - membrane concentrated water outlet; 27 - membrane water outlet; 28 - membrane speed reducer motor; 29 - emptying port; 30 - membrane support; 31 - membrane; 32 - center tube; 33 - cleaning concentrated water return pipe; 34 - concentrated water return pipe; 35 - cleaning water return pipe; 36 - backwashing water inlet pipe; 37 - water outlet pipe; 38 - flushing water inlet pipe; 39 - cleaning water tank; 40 - water tank; 41 - cleaning pump; 51 - first reaction tank; 52 - deamination device water inlet pipe; 53 - first dosing pipe; 54 - deamination device water inlet pump; 55 - air blower; 56 - dissolved air pump; 57 - jet mixer; 58 - dissolved air deamination reactor; 59 - gas outlet; 60 - dissolved air releaser; 61 - water outlet pipe; 62 - degassing tank; 63 - second reaction tank; 64 - third reaction tank; 65 - second dosing pipe; 66 - third dosing pipe; 67 - deamination device sedimentation tank; 68 - mixing tank; 69 - air suction fan; 70 - absorption tower; 71 - circulating water tank; 72 - spraying pump; 73 - anaerobic return pipe; 74 - anaerobic water inlet pump; 81 - primary anoxic tank; 82 - primary aerobic tank; 83 - primary membrane tank; 84 - secondary anoxic tank; 85 - secondary aerobic tank; 86 - secondary membrane tank; 87 - biochemical water inlet pipe; 88 - primary MBR membrane; 89 - secondary MBR membrane. DETAILED DESCRIPTION

[0042] In order to facilitate those skilled in the art to understand and implement the present application, the present application will be further described in detail below in conjunction with examples. It should be understood that the examples described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0043] A fruit and vegetable waste anaerobic fermentation biogas slurry treatment system, comprising:

[0044] A grating device is used to filter out larger fibers or impurities in the biogas slurry of the fermentation system, and the filtered biogas slurry of the grating device is input into a centrifugal machine, and the generated biogas residue is input into a biogas fertilizer system,

[0045] A centrifugal machine is used to centrifugally process the biogas slurry filtered by the grating, and the waste water output by the centrifugal machine is output into a filter press, and the biogas residue generated by the centrifugal machine is output into a biogas fertilizer system,

[0046] A filter press is used to filter press the biogas slurry output by the centrifugal machine, and the waste water output by the filter press is output into a membrane separation device, and the biogas residue generated by the filter press is output into a biogas fertilizer system,

[0047] The small fibrous organic matter in the biogas slurry is removed by the centrifuge and filter press, so that the suspended solids content in the separated wastewater is less than 1000 mg / L, and the biogas residue separated by the grid, centrifuge and filter press is introduced into the biogas fertilizer system to produce organic fertilizer by composting.

[0048] The membrane separation device is used for membrane separation of the wastewater input by the filter press to generate product water and concentrated water, the product water is input into the deamination device, and the concentrated water is input into the fermentation system.

[0049] The deamination device is used for denitrification treatment of the product water of the membrane separation device and part of the effluent of the anaerobic sedimentation tank, and the wastewater after the denitrification treatment is input into the anaerobic reactor.

[0050] The anaerobic reactor is used for preliminary COD Cr removal treatment of the wastewater, and the wastewater after the preliminary COD Cr removal treatment is input into the anaerobic sedimentation tank, and the produced biogas is input into the biogas system.

[0051] The anaerobic sedimentation tank is used for anaerobic sedimentation of the wastewater, part of the effluent is backflowed to the deamination device, the remaining part of the effluent is introduced into the biochemical treatment device, part of the sludge (low in concentration and pumpable) of the anaerobic sedimentation tank is backflowed to the anaerobic reactor, and the remaining part of the sludge (low in concentration and pumpable) is output to the first sludge dewatering system.

[0052] The biochemical treatment device is used for further removal of COD Cr , ammonia nitrogen and total nitrogen from the wastewater, the sludge (low in concentration and pumpable) produced by the biochemical treatment device is output to the first sludge dewatering system, and the effluent of the biochemical treatment device is input into the coagulation reaction sedimentation tank.

[0053] The coagulation reaction sedimentation tank is used for further removal of total phosphorus, color and part of COD Cr from the wastewater, and the sludge (low in concentration and pumpable) produced by the coagulation reaction sedimentation tank is input into the second sludge dewatering system.

[0054] In some embodiments, part of the sludge (low in concentration and pumpable) produced by the first sludge dewatering system is transported into the fermentation system, mixed fermentation is performed in the fermentation system with the concentrated water output by the membrane separation device, the produced biogas slurry is input into the grid device, and the produced biogas is input into the biogas system. The filtrate output by the first sludge dewatering system is input into the deamination device.

[0055] In some embodiments, the sludge produced by the second sludge dewatering system is transported out for treatment, and the filtrate output by the second sludge dewatering system is input into the deamination device.

[0056] In some embodiments, the grid device comprises a filtrate pool 10 and a cylindrical screen 3 arranged above the filtrate pool 10, the input end of the screw conveyor 4 extends into the cylindrical screen 3, a notch is arranged on the input end housing of the screw conveyor 4, the notch is connected with the slag collecting groove 13, the edge of the slag collecting groove 13 is provided with a slag scraping plate 14 extending to the inner wall of the screen 3, the outer wall of the screen 3 is provided with a slag cleaning device 8 which is stationary relative to the screen 3, the slag cleaning device 8 comprises a metal brush and a flushing water pipe, one end of the screw conveying rod of the screw conveyor 4 extends out of the input end housing and is connected with the screen 3 through a drum support 12, one end of the water inlet cover 2 is connected with one end of the water inlet pipe 1, the water inlet of the water inlet pipe 1 is conveyed into the cylindrical screen 3 through the water inlet cover 2, the output end of the screw conveyor 4 is provided with a pressing area 5, the pressing area 5 is connected with a slag outlet 6. The filtrate pool 10 is connected with the input port of the filtrate lifting pump 11 through a pipeline, and the output port of the filtrate lifting pump 11 outputs biogas slurry through a pipeline. The screw conveying rod of the screw conveyor 4 is driven to rotate by a speed reducer motor 7, the screw conveying rod of the screw conveyor 4 is arranged in a housing, and the housing is arranged above the filtrate pool 10 through a mounting bracket 9.

[0057] The structure of the grid is shown in Figures 2-3 The biogas slurry of the fermentation system first enters the water inlet cover 2 from the water inlet pipe 1, and then flows into the screen 3 from the water inlet cover 2, the screw conveying rod of the screw conveyor 4 rotates to drive the screen 3 to rotate, the suspended solids in the biogas slurry are intercepted on the screen 3, the filtrate flows into the filtrate pool 10 below, the suspended solids on the screen 3 are cleaned by the slag scraping plate 14 during the rotation of the drum, and the slag cleaning device 8 above the drum also plays a cleaning role on the suspended solids, the slag cleaning device 8 comprises a metal brush and a flushing water pipe, the cleaned suspended solids fall into the slag collecting groove 13 in the drum, the slag collecting groove 13 is connected with the screw conveyor 4, the biogas sludge in the slag collecting groove 13 is conveyed to the pressing area by the screw conveyor 4 for dewatering, the dewatered filtrate flows into the filtrate pool 10, and the dewatered biogas sludge is discharged from the slag outlet 6, a biogas sludge collecting device is placed below the slag outlet 6, the collected biogas sludge enters the biogas fertilizer system, the filtrate pool 10 is connected with the filtrate lifting pump 11, and the filtrate is conveyed to the centrifuge by the filtrate lifting pump 11.

[0058] The centrifuge can adopt a horizontal screw centrifuge, the biogas sludge separated by the centrifuge enters the biogas fertilizer system, and the clear liquid of the centrifuge enters the filter press, after the treatment of the centrifuge, the larger suspended solids in the biogas slurry are removed, and the concentration of the suspended solids in the clear liquid of the centrifuge is less than 5000 mg / L.

[0059] The filter press adopts a plate-and-frame filter press, the operating pressure of the filter press is 0.8-1.5 MPa, and the air permeability of the filter cloth used by the filter press is less than 10 L / (m 2 ·s), after the treatment of the filter press, the smaller suspended solids in the biogas slurry are removed, and the concentration of the suspended solids in the filtrate of the filter press is less than 1000 mg / L.

[0060] The filtrate from the filter press is passed through a membrane separation device to remove residual suspended solids from the biogas slurry, ensuring that the suspended solids content in the permeate of the membrane separation device is less than 10 mg / L, and the suspended solids content in the concentrate of the membrane separation device is controlled at 8000-10000 mg / L. The concentrate of the membrane separation device is returned to the fermentation system, and the permeate of the membrane separation device enters the deammoniation device.

[0061] In some embodiments, a schematic diagram of the membrane separation device is shown below. Figure 4 As shown, the membrane separation device includes an inlet water tank 21, a cleaning water tank 39, and a product water tank 40.

[0062] The inlet tank 21 is connected to the input end of the membrane unit inlet pump 22 via a pipe. The output end of the membrane unit inlet pump 22 is connected to the membrane inlet pipe 25 of the membrane module via the membrane unit inlet pipe. A switch valve is installed on the membrane unit inlet pipe. The membrane concentrate outlet 26 of the membrane module is connected to the inlet tank 21 via a first concentrate pipe. A switch valve is installed on the first concentrate pipe. The membrane concentrate outlet 26 of the membrane module is also connected to the cleaning water tank 39 via a second concentrate pipe. A switch valve is installed on the second concentrate pipe. The membrane unit air compressor 23 is connected to the membrane inlet pipe 25 of the membrane module via a flushing air pipe. A switch valve is installed on the flushing air pipe. The membrane module is mounted above the cleaning water tank 39 via a membrane support 30. The drain port 29 of the membrane module is located above the cleaning water tank 39. The membrane permeate outlet 27 of the membrane module is connected to the cleaning water tank 39 through the cleaning permeate return pipe 35. A switch valve is installed on the cleaning permeate return pipe 35. The membrane permeate outlet 27 of the membrane module is connected to the output port of the cleaning pump 41 through the backwash inlet pipe 36. A switch valve is installed on the backwash inlet pipe 36. The membrane permeate outlet 27 of the membrane module is connected to the permeate tank 40 through the permeate pipe 37. A switch valve is installed on the permeate pipe 37. The cleaning water tank 39 is connected to the input port of the cleaning pump 41 through a pipe. The output port of the cleaning pump 41 is also connected to the membrane inlet pipe 25 of the membrane module through the flushing inlet pipe 38. A switch valve is installed on the flushing inlet pipe 38.

[0063] The membrane module includes a membrane housing 24, within which a vertically arranged central tube 32 is disposed. The bottom end of the central tube 32 is sealed and passes through the membrane housing 24, connecting to the rotating shaft of the membrane geared motor 28. A membrane permeate outlet 27 is disposed at the top of the membrane housing 24. The top end of the central tube 32 is sealed and inserted into the membrane permeate outlet 27 and can rotate relative to the membrane permeate outlet 27 (for example, the bottom end of the membrane permeate outlet 27 is an elastic sealing sleeve fitted onto the top end of the central tube 32). Multiple membrane sheets 31 are sequentially distributed along the central tube 32. Preferably, the membrane sheets 31 are disc-shaped and are aligned with the central tube. The tube 32 is coaxially arranged, and a membrane inlet pipe 25 is provided inside the membrane housing 24. The bottom end of the membrane inlet pipe 25 extends out of the membrane housing 24 and is sealed. The membrane inlet pipe 25 is connected to each membrane inlet branch pipe. Water distribution holes are opened on the membrane inlet branch pipe. Membrane inlet branch pipes are provided between adjacent membrane sheets 31. The outer surface of the membrane sheet 31 is a filter layer. The inside of the membrane sheet 31 contains a spiral water production channel. One end of the water production channel extends into the filter layer, and the other end is connected to the central tube 32. A membrane concentrate outlet 26 is provided at the top of the membrane housing 24, and an air vent 29 is provided at the bottom of the membrane housing 24.

[0064] The biogas slurry in the inlet tank 21 is transported to the inlet pipe 25 by the membrane unit inlet pump 22. The membrane geared motor 28 drives the central tube 32 to rotate, which in turn drives each membrane 31 to rotate. Utilizing the centrifugal force and hydraulic shear force generated by the rotational motion, strong turbulence is formed between the membrane 31 and the membrane inlet branch pipe, which can effectively remove the filter layer of the membrane 31 and reduce the fouling on the membrane surface. The filter layer of the membrane 31 has a filter accuracy of 5-30 nm. The biogas slurry input through the inlet pipe 25 is transported to each membrane inlet branch pipe and then to the corresponding membrane 31. The permeate water enters the internal permeate channel through the filter layer of the membrane 31. One end of the permeate channel extends into the filter layer, and the other end is connected to the central tube 32. Then, it flows out of the membrane module through the top of the hollow central tube 32 and the membrane permeate outlet 27.

[0065] In another usage method, the biogas slurry in the inlet tank 21 is transported to the inlet pipe 25 through the membrane device inlet pump 22, while air is simultaneously transported to the inlet pipe 25 through the membrane device air compressor 23. This can provide a certain degree of rinsing effect on the filter layer of the membrane 31.

[0066] In another usage method, the cleaning pump 41 delivers water from the cleaning water tank 39 to the inlet pipe 25 through the flushing inlet pipe 38 to rinse the filter layer of the membrane 31 with clean water. Alternatively, air can be delivered to the inlet pipe 25 simultaneously through the membrane unit air compressor 23.

[0067] In this embodiment, the membrane geared motor 28 drives the central tube 32 and the membrane 31 to rotate at a speed of 100-300 r / min. The permeate flows out from the membrane permeate outlet 27. Since it continuously enters the membrane housing 24 through the membrane inlet pipe 25, it will be output from the top membrane permeate outlet 27 under water pressure and enter the permeate tank 40 through the permeate pipe 37. The concentrate flows out from the membrane concentrate outlet 26 and enters the feed water tank 21 through the concentrate return pipe 34. After running for a period of time, the wastewater in the feed water tank 21 is discharged all at once.

[0068] Furthermore, in this embodiment, the membrane separation device runs continuously for 30-60 minutes, then stops. Simultaneously, the cleaning pump 41 performs a flushing, backwashing, and air washing on the membrane 31. Air washing is performed simultaneously during flushing or backwashing. During flushing, flushing water enters the membrane housing 24 from the flushing inlet pipe 38, while the membrane unit air compressor 23 sends compressed air into the membrane inlet pipe 25. During backwashing, backwash water enters the membrane housing 24 from the backwash inlet pipe 36, while the membrane unit air compressor 23 sends compressed air into the membrane inlet pipe 25. After flushing and backwashing, the membrane separation device continues to operate. When the membrane separation device requires chemical cleaning, the membrane housing 24 is emptied through the drain port 29. During cleaning, the permeate flows back to the cleaning water tank 39 from the cleaning permeate return pipe 35, and the concentrate flows back to the cleaning water tank 39 from the cleaning concentrate return pipe 33. During cleaning, the membrane unit air compressor 23 sends compressed air into the membrane inlet pipe 25.

[0069] Furthermore, in this embodiment, there are two sets of cleaning water tanks 39 and cleaning pumps 41. Each set of cleaning water tanks 39 is connected to the inlet of the corresponding set of cleaning pumps 41 through the corresponding set of pipes. One set of cleaning water tanks 39 and cleaning pumps 41 is used for rinsing and backwashing, and the other set of cleaning water tanks 39 and cleaning pumps 41 is used for chemical cleaning.

[0070] The permeate from the membrane separation unit passes through an ammonia removal unit to remove most of the ammonia nitrogen from the wastewater. 50-60% of the ammonia nitrogen is then absorbed by a phosphoric acid solution after being stripped by air flotation to obtain ammonium phosphate. 30-40% of the ammonia nitrogen is then precipitated by chemical reaction to obtain magnesium ammonium phosphate. The ammonia nitrogen concentration in the permeate from the ammonia removal unit is controlled at 100-200 mg / L. The permeate from the ammonia removal unit is then mixed with the effluent from the anaerobic sedimentation tank.

[0071] In some embodiments, a schematic diagram of the ammonia removal device is shown below. Figure 5 As shown, the ammonia removal device includes a first reaction tank 51, a dissolved gas ammonia removal reactor 58, an absorption tower 70, a degassing tank 62, a second reaction tank 63, a third reaction tank 64, a sedimentation tank 67, and a mixing tank 68.

[0072] The first reaction tank 51 is equipped with an inlet pipe 52 for the ammonia removal device and a first dosing pipe 53. An aeration unit is installed at the bottom of the first reaction tank 51. The outlet at the bottom of the first reaction tank 51 is connected to the inlet of the dissolved gas ammonia removal reactor 58 via an inlet pump 54 for the ammonia removal device and a jet mixer 57. The outlet at the top of the first reaction tank 51 is connected to the inlet of a blower 69. A guide plate, which is cylindrical, is installed at the inlet of the dissolved gas ammonia removal reactor 58. The water inlet is tangent to the guide plate and inclined upwards. A conical baffle is installed at the bottom of the dissolved gas deammoniation reactor 58, and a dissolved gas release device 60 is installed at the top of the conical baffle. An outlet is located below the conical baffle inside the dissolved gas deammoniation reactor 58. The outlet of the dissolved gas deammoniation reactor 58 is connected to the degassing tank 62 via an outlet pipe 61. The outlet of the dissolved gas deammoniation reactor 58 is also connected to the dissolved gas inlet of the dissolved gas deammoniation reactor 58 via a dissolved gas pump 56. The dissolved gas inlet is connected to the dissolved gas release device 60 via a pipeline. The air outlet 59 at the top of the degassing tank 58 is connected to the air inlet of the exhaust fan 69. The air outlet at the top of the degassing tank 62 is connected to the air inlet of the exhaust fan 69. An aeration unit is installed at the bottom of the degassing tank 62. The bottom of the degassing tank 62 is connected to the bottom of the second reaction tank 63. The top of the second reaction tank 63 is connected to the top of the third reaction tank 64 via an overflow. The bottom of the third reaction tank 64 is connected to the bottom of the overflow channel. The top of the overflow channel is connected to the inlet pipe of the sedimentation tank 67 of the ammonia removal device. A second dosing pipe 65 is installed on the second reaction tank 63. The third reaction... A third dosing pipe 66 is installed on tank 64. The effluent pipe of the sedimentation tank 67 of the ammonia removal device is connected to the mixing tank 68. The mixing tank 68 is equipped with an anaerobic reflux pipe 73, which is connected to the effluent outlet of the anaerobic sedimentation tank. The effluent outlet at the bottom of the mixing tank 68 is connected to the inlet of the anaerobic influent pump 74. The effluent outlet of the anaerobic influent pump 74 is connected to the inlet of the anaerobic reactor. The aeration units at the bottom of the first reaction tank 51 and the deaeration tank 62 are both connected to the blower 55. The exhaust fan 69 is connected to the absorption tower 70. A circulating water tank 71 is installed at the bottom of the absorption tower 70, and the circulating water tank 71 is connected to the inlet of the absorption tower 70 through a spray pump 72.

[0073] Alkaline solution (NaOH solution, etc.) is added to the first reaction tank 51 through the first dosing pipe 53 to adjust the pH of the solution in the first reaction tank 51 to about 10.0. The first reaction tank 51 is aerated and stirred. The aeration unit includes an aeration pipe and a microporous aeration disc installed on the aeration pipe. The aeration intensity is 5-10 L / (m²). 2The dissolved air deammonia removal reactor 58 adopts a swirling inlet. A jet mixer 57 is installed on the inlet pipe of the dissolved air deammonia removal reactor 58, and a guide plate is connected to the inlet to form an upward swirling flow. A conical baffle is installed at the bottom of the dissolved air deammonia removal reactor 58, and a dissolved air release device 60 is installed at the top of the conical baffle. The outlet is located below the conical baffle. The inlet of the dissolved air pump 56 is connected to the outlet of the dissolved air deammonia removal reactor 58 (or it can be led out from the outlet pipe 61). The outlet pipe of the dissolved air pump 56 is connected to the dissolved air release device 60. The flow rate of the dissolved air pump 56 is 40% to 100% of the inlet flow rate of the dissolved air deammonia removal reactor 58. The hydraulic retention time of the dissolved air deammonia removal reactor 58 is 30 to 60 minutes. The degassing tank 62 adopts aeration and stirring. The aeration unit of the degassing tank 62 includes an aeration pipe and a microporous aeration disc installed on the aeration pipe. The aeration intensity is 5 to 10 L / (m³). 2 In the second reaction tank 63, magnesium chloride solution is added through the second dosing pipe 65. The hydraulic retention time of the second reaction tank 63 is 10-30 min. In the second reaction tank 63, ammonia nitrogen reacts with magnesium ions and phosphate ions to generate magnesium ammonium phosphate. In the third reaction tank 64, flocculant is added through the third dosing pipe 66. The flocculant is a 0.1-0.2% concentration polyacrylamide solution. The third reaction tank 64 is connected to the inlet pipe of the sedimentation tank 67 of the deammoniation device through the overflow channel. The effluent from the sedimentation tank 67 of the deammoniation device is mixed with part of the effluent from the anaerobic sedimentation tank in the mixing tank 68. The ratio of the effluent from the sedimentation tank 67 of the deammoniation device to the effluent from the anaerobic sedimentation tank is 1:1 to 2:1. The exhaust fan 68 sends the tail gas from the first reaction tank 51, the dissolved gas deammoniation reactor 58 and the degassing tank 62 to the reaction tower 70. The circulating water tank 71 is equipped with phosphoric acid solution. The ammonium phosphate solution generated after the tail gas is absorbed is used as a raw material for the production of nitrogen and phosphorus fertilizer.

[0074] The mixed wastewater in mixing tank 68 enters the anaerobic reactor via anaerobic influent pump 74, where most of the COD in the wastewater is removed. Cr Controlling COD in anaerobic reactor effluent Cr The concentration is 1000-1500 mg / L. After the effluent from the anaerobic reactor passes through the anaerobic sedimentation tank, part of the effluent from the anaerobic sedimentation tank enters the biological treatment device, and the other part of the effluent is returned to the mixing tank 68 through the anaerobic return pipe 73. The sludge from the anaerobic sedimentation tank is returned to the anaerobic reactor. The remaining sludge discharged from the anaerobic sedimentation tank enters the first sludge dewatering system. The biogas produced by the anaerobic reactor enters the biogas system.

[0075] In this embodiment, the anaerobic reactor is a UASB reactor. The anaerobic reactor is equipped with a circulation pump to enhance the mixing intensity. The circulation pump and the anaerobic feed pump 74 are connected to the anaerobic reactor's inlet pipe. The anaerobic sedimentation tank includes a degassing tank and a sedimentation tank. The degassing tank uses mechanical stirring for degassing, and the surface hydraulic load of the sedimentation tank is less than 0.5 m.3 / (m 2 ·h), the sludge settled in the anaerobic sedimentation tank is returned to the inlet pipe of the anaerobic reactor by a sludge discharge pump. The sludge discharge pump operates continuously, and the flow rate of the sludge discharge pump is 10 to 20% of the effluent flow rate of the sedimentation tank.

[0076] The effluent from the anaerobic sedimentation tank is treated by a biological treatment device to remove COD from the wastewater. Cr Ammonia nitrogen and total nitrogen are removed from the wastewater. The excess sludge discharged from the biological treatment unit enters the first sludge dewatering system. The dewatered sludge from the first sludge dewatering system enters the fermentation system. The effluent from the biological treatment unit passes through a coagulation reaction sedimentation tank to remove total phosphorus, color, and part of the COD. Cr The sludge discharged from the coagulation reaction sedimentation tank enters the second sludge dewatering system. The sludge dewatered by the second sludge dewatering system is transported off-site for disposal. The filtrate produced by the first and second sludge dewatering systems is returned to the ammonia removal device. The filtrate is mixed with the permeate from the membrane separation device and part of the effluent from the anaerobic sedimentation tank and enters the first reaction tank 51 of the ammonia removal device. The effluent from the coagulation reaction sedimentation tank is discharged in compliance with standards.

[0077] In some embodiments, a schematic diagram of the biochemical treatment device is shown below. Figure 6 As shown, the biochemical treatment device includes a primary anoxic tank 81, a primary aerobic tank 82, a primary membrane tank 83, a secondary anoxic tank 84, a secondary aerobic tank 85, and a secondary membrane tank 86.

[0078] The primary anoxic tank 81 is equipped with a biochemical inlet pipe 87 and a primary circulation return pipe. The bottom of the primary anoxic tank 81 is connected to the bottom of the primary aerobic tank 82. A jet aerator is installed in the primary anoxic tank 81. The outlet of the primary aerobic tank 82 is connected to the inlet of the primary membrane tank 83. The circulation outlet at the bottom of the primary membrane tank 83 is connected to the primary circulation return pipe of the primary anoxic tank 81 through a return pump. The permeate outlet of the primary MBR membrane in the primary membrane tank 83 is connected to the secondary inlet pipe installed on the secondary anoxic tank 84 via a water pump. The secondary anoxic tank 84 is equipped with a secondary circulation return pipe. The bottom of the secondary anoxic tank 84 is connected to the bottom of the secondary aerobic tank 85. The outlet of the secondary aerobic tank 85 is connected to the inlet of the secondary membrane tank 86. The circulation outlet at the bottom of the secondary membrane tank 86 is connected to the secondary circulation return pipe of the secondary anoxic tank 84 via a return pump. The permeate outlet of the secondary MBR membrane in the secondary membrane tank 86 is connected to the inlet of the coagulation reaction sedimentation tank.

[0079] The air compressor's output port is connected to the jet aerator in the primary aerobic tank 82, the jet aerator in the secondary aerobic tank 85, the aerator located below the primary MBR membrane in the primary membrane tank 83, and the aerator located below the secondary MBR membrane in the secondary membrane tank 86.

[0080] The bottom of the primary aerobic tank 82 is connected to the inlet of the primary aerobic tank pump, and the outlet of the primary aerobic tank pump is connected to the jet aerator inside the primary aerobic tank 82 via a pipeline. The bottom of the secondary aerobic tank 85 is connected to the inlet of the secondary aerobic tank pump, and the outlet of the secondary aerobic tank pump is connected to the jet aerator inside the secondary aerobic tank 85 via a pipeline.

[0081] The primary membrane tank 83 is connected to the primary anoxic tank 81 via a return pump. The permeate from the primary membrane tank 83 enters the secondary anoxic tank 84. The secondary membrane tank 86 is connected to the secondary anoxic tank 84 via a return pump. MBR membranes are installed in the primary membrane tank 83 and the secondary membrane tank 86. The MBR membranes are hollow fiber ultrafiltration membranes. The denitrification sludge load in the primary anoxic tank 81 is controlled at 0.03–0.06 kgTN / (kgMLSS·d), the denitrification sludge load in the secondary anoxic tank 84 is controlled at 0.02–0.04 kgTN / (kgMLSS·d), the nitrification sludge load in the primary aerobic tank 82 is controlled at 0.01–0.03 kgNH3-N / (kgMLSS·d), and the nitrification sludge load in the secondary aerobic tank 85 is controlled at 0.01–0.02 kgNH3-N / (kgMLSS·d).

[0082] In some embodiments, the coagulation reaction sedimentation tank includes a reaction tank and a sedimentation tank. The reaction tank includes a first reaction tank, a second reaction tank, and a third reaction tank connected in series. The inlet of the first reaction tank serves as the inlet of the coagulation reaction sedimentation tank, and the outlet of the third reaction tank is connected to the sedimentation tank. Depending on the water quality, the reagent added to the first reaction tank includes potassium ferrate or an adsorbent, and the reagent added to the second reaction tank includes polyferric chloride or polyaluminum chloride. Potassium ferrate can effectively remove COD from the water. Cr Total phosphorus and color are primarily removed from water by polyaluminum chloride or polyferric chloride, while adsorbents primarily remove COD. Cr To determine color and other parameters, a flocculant is added to the third reaction tank. The flocculant used is a 0.1–0.2% concentration polyacrylamide solution. An inclined tube sedimentation tank is used, and the surface hydraulic load of the sedimentation tank is less than 0.5 m. 3 / (m 2 ·h).

[0083] The process of this invention can effectively recover organic matter and nitrogen and phosphorus substances from biogas slurry, and reduce residual COD in biogas slurry. Cr Biogas can be recovered through anaerobic treatment, and the remaining COD in the biogas slurry can be recovered. Cr After biochemical treatment and coagulation sedimentation, ammonia nitrogen, total nitrogen and total phosphorus can meet the Class A standard in the "Discharge Standard of Pollutants for Urban Wastewater Treatment Plants" (GB18918-2002).

[0084] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A fruit and vegetable waste anaerobic fermentation biogas slurry treatment system, comprising a bar screen device, characterized in that, The bar screen filter removes the biogas slurry from the fermentation system and inputs the filtered biogas slurry into a centrifuge. The biogas residue produced by the bar screen is input into the biogas fertilizer system. The centrifuge centrifuges process the biogas slurry filtered by the grid, and the wastewater output from the centrifuge is sent to the filter press, while the biogas residue produced by the centrifuge is sent to the biogas fertilizer system. The filter press filters the biogas slurry output from the centrifuge, the wastewater output from the filter press is sent to the membrane separation device, and the biogas residue produced by the filter press is sent to the biogas fertilizer system. The membrane separation device performs membrane separation on the wastewater input from the filter press to generate permeate and concentrate. The permeate is input into the ammonia removal device, and the concentrate is input into the fermentation system. The denitrification device denitrifies the permeate from the membrane separation device and part of the effluent from the anaerobic sedimentation tank. The denitrified wastewater is then fed into the anaerobic reactor. The anaerobic reactor performs preliminary COD treatment on the wastewater. Cr Removal treatment, preliminary removal of COD Cr The wastewater is then fed into an anaerobic sedimentation tank, and the biogas produced is fed into a biogas system. The anaerobic sedimentation tank performs anaerobic sedimentation on the wastewater. Part of the effluent is returned to the ammonia removal device, and the remaining part of the effluent enters the biological treatment device. Part of the sludge from the anaerobic sedimentation tank is returned to the anaerobic reactor, and the remaining part of the sludge is output to the first sludge dewatering system. The biological treatment unit further removes COD from the input wastewater. Cr Ammonia nitrogen and total nitrogen, the sludge produced by the biological treatment unit is output to the first sludge dewatering system, and the effluent from the biological treatment unit is input to the coagulation reaction sedimentation tank. The coagulation reaction sedimentation tank further removes total phosphorus, color, and COD from the wastewater. Cr The resulting sludge is fed into the second sludge dewatering system. Part of the sludge produced by the first sludge dewatering system is transported to the fermentation system, where it is mixed with the concentrated water output from the membrane separation unit for fermentation. The resulting biogas slurry is fed into the bar screen, and the generated biogas is fed into the biogas system. The filtrate produced by the first sludge dewatering system is fed into the ammonia removal unit. The ammonia removal device includes a first reaction tank (51), a dissolved gas ammonia removal reactor (58), an absorption tower (70), a degassing tank (62), a second reaction tank (63), a third reaction tank (64), a sedimentation tank (67) for the ammonia removal device, and a mixing tank (68). Alkali solution is added to the first reaction tank (51) through the first dosing pipe (53), magnesium chloride solution is added to the second reaction tank (63) through the second dosing pipe (65), and flocculant is added to the third reaction tank (64) through the third dosing pipe (66). The biochemical treatment device includes a primary anoxic tank (81), a primary aerobic tank (82), a primary membrane tank (83), a secondary anoxic tank (84), a secondary aerobic tank (85), and a secondary membrane tank (86).

2. The anaerobic fermentation biogas slurry treatment system for fruit and vegetable waste according to claim 1, characterized in that, The sludge produced by the second sludge dewatering system is transported off-site for treatment, and the filtrate output from the second sludge dewatering system is fed into the ammonia removal device.

3. The anaerobic fermentation biogas slurry treatment system for fruit and vegetable waste according to claim 1, characterized in that, The grid device includes a filtrate tank (10) and a cylindrical screen (3) set above the filtrate tank (10). The input end of the screw conveyor (4) extends into the cylindrical screen (3). A slot is provided on the outer shell of the input end of the screw conveyor (4), and the slot is connected to the slag collection trough (13). A scraper (14) extending to the inner wall of the screen (3) is provided on the edge of the slag collection trough (13). A cleaning device (8) that is stationary relative to the screen (3) is provided on the outer wall of the screen (3). The cleaning device (8) includes a metal brush and a flushing water pipe. One end of the screw conveyor rod of the screw conveyor (4) The input end housing extends out and is connected to the screen (3) through the drum bracket (12). One end of the water inlet cover (2) is connected to one end of the water inlet pipe (1). The water inlet pipe (1) is transported to the cylindrical screen (3) through the water inlet cover (2). The output end of the screw conveyor (4) is provided with a pressing area (5). The pressing area (5) is connected to the slag outlet (6). The filtrate tank (10) is connected to the input port of the filtrate lifting pump (11) through a pipe. The output port of the filtrate lifting pump (11) outputs biogas slurry through a pipe. The screw conveyor rod of the screw conveyor (4) is driven to rotate by the geared motor (7).

4. The anaerobic fermentation biogas slurry treatment system for fruit and vegetable waste according to claim 1, characterized in that, The membrane separation device includes an inlet tank (21), a membrane module, a cleaning water tank (39), and a product water tank (40). The inlet tank (21) is connected to the input end of the membrane device inlet pump (22) via a pipe. The output end of the membrane device inlet pump (22) is connected to the membrane inlet pipe (25) of the membrane module via the membrane device inlet pipe. A switch valve is installed on the membrane device inlet pipe. The membrane concentrate outlet (26) of the membrane module is connected to the inlet tank (21) via a first concentrate pipe. A switch valve is installed on the first concentrate pipe. The membrane concentrate outlet (26) of the membrane module is also connected to the cleaning water tank (39) via a second concentrate pipe. A switch valve is installed on the second concentrate pipe. The membrane device air compressor (23) is connected to the membrane inlet pipe (25) of the membrane module via a flushing air pipe. A switch valve is installed on the flushing air pipe. The membrane module is mounted on the cleaning water tank via a membrane support (30). Above the washing tank (39), the drain port (29) of the membrane module is located above the washing tank (39). The membrane permeate outlet (27) of the membrane module is connected to the washing tank (39) through the washing permeate return pipe (35). A switch valve is installed on the washing permeate return pipe (35). The membrane permeate outlet (27) of the membrane module is connected to the output port of the cleaning pump (41) through the backwash inlet pipe (36). A switch valve is installed on the backwash inlet pipe (36). The membrane permeate outlet (27) of the membrane module is connected to the permeate tank (40) through the permeate pipe (37). A switch valve is installed on the permeate pipe (37). The washing tank (39) is connected to the input port of the cleaning pump (41) through a pipe. The output port of the cleaning pump (41) is also connected to the membrane inlet pipe (25) of the membrane module through the flushing inlet pipe (38). A switch valve is installed on the flushing inlet pipe (38).

5. The anaerobic fermentation biogas slurry treatment system for fruit and vegetable waste according to claim 4, characterized in that, The membrane module includes a membrane housing (24), inside which is a vertically arranged central tube (32). The bottom end of the central tube (32) is sealed and passes through the membrane housing (24) to be connected to the rotating shaft of the membrane geared motor (28). A membrane permeate outlet (27) is provided at the top of the membrane housing (24). The top end of the central tube (32) is sealed and inserted into the membrane permeate outlet (27) and can rotate relative to the membrane permeate outlet (27). Multiple membrane sheets (31) are distributed sequentially along the central tube (32). The membrane sheets (31) are disc-shaped and coaxially arranged with the central tube (32). The membrane inlet pipe (25) is installed inside. The bottom end of the membrane inlet pipe (25) extends out of the membrane shell (24) with a seal. The membrane inlet pipe (25) is connected to each membrane inlet branch pipe. Water distribution holes are opened on the membrane inlet branch pipe. Membrane inlet branch pipes are set between adjacent membrane sheets (31). The outer surface of the membrane sheet (31) is a filter layer. The membrane sheet (31) contains a spiral water production channel. One end of the water production channel extends into the filter layer, and the other end is connected to the central pipe (32). A membrane concentrate outlet (26) is set at the top of the membrane shell (24), and an air outlet (29) is set at the bottom of the membrane shell (24).

6. The anaerobic fermentation biogas slurry treatment system for fruit and vegetable waste according to claim 1, characterized in that, The first reaction tank (51) is equipped with an inlet pipe (52) for the deammoniation device and a first dosing pipe (53). An aeration unit is installed at the bottom of the first reaction tank (51). The outlet at the bottom of the first reaction tank (51) is connected to the inlet of the dissolved gas deammoniation reactor (58) via the deammoniation device inlet pump (54) and jet mixer (57). The outlet at the top of the first reaction tank (51) is connected to the inlet of the exhaust fan (69). A guide plate is installed inside the dissolved gas deammoniation reactor (58) at the position of the inlet of the dissolved gas deammoniation reactor (58). The guide plate is a cylindrical plate. The water inlet direction of the dissolved gas deammoniation reactor (58) is opposite to that of the guide plate. The dissolved gas deammonia removal reactor (58) is inclined upwards and has a conical baffle at the bottom. A dissolved gas release device (60) is installed at the top of the conical baffle. An outlet is located below the conical baffle inside the dissolved gas deammonia removal reactor (58). The outlet of the dissolved gas deammonia removal reactor (58) is connected to the degassing tank (62) through an outlet pipe (61). The outlet of the dissolved gas deammonia removal reactor (58) is also connected to the dissolved gas inlet of the dissolved gas deammonia removal reactor (58) through a dissolved gas pump (56). The dissolved gas inlet is connected to the dissolved gas release device (60) through a pipeline. The gas outlet (59) at the top of the dissolved gas deammonia removal reactor (58) is connected to the air inlet of the exhaust fan (69). The air outlet at the top of the degassing tank (62) is connected to the air inlet of the exhaust fan (69). An aeration unit is installed at the bottom of the degassing tank (62). The bottom of the degassing tank (62) is connected to the bottom of the second reaction tank (63). The top of the second reaction tank (63) is connected to the top of the third reaction tank (64) via an overflow. The bottom of the third reaction tank (64) is connected to the bottom of the overflow channel. The top of the overflow channel is connected to the inlet pipe of the sedimentation tank (67) of the ammonia removal device. A second dosing pipe (65) is installed on the second reaction tank (63), and a third dosing pipe (66) is installed on the third reaction tank (64). The outlet pipe of the sedimentation tank (67) of the ammonia removal device is connected to the mixing tank (68). The mixing tank (68) is equipped with an anaerobic reflux pipe (73), which is connected to the outlet of the anaerobic sedimentation tank. The outlet at the bottom of the mixing tank (68) is connected to the inlet of the anaerobic inlet pump (74), and the outlet of the anaerobic inlet pump (74) is connected to the inlet of the anaerobic reactor. The aeration unit at the bottom of the first reaction tank (51) and the aeration unit at the bottom of the degassing tank (62) are both connected to the blower (55). The outlet of the exhaust fan (69) is connected to the absorption tower (70). The bottom of the absorption tower (70) is equipped with a circulating water tank (71), which is connected to the inlet of the absorption tower (70) through a spray pump (72).

7. The anaerobic fermentation biogas slurry treatment system for fruit and vegetable waste according to claim 1, characterized in that, The primary anoxic tank (81) is equipped with a biochemical inlet pipe (87) and a primary circulation return pipe. The bottom of the primary anoxic tank (81) is connected to the bottom of the primary aerobic tank (82). A jet aerator is installed in the primary anoxic tank (81). The outlet of the primary aerobic tank (82) is connected to the inlet of the primary membrane tank (83). The circulation outlet at the bottom of the primary membrane tank (83) is connected to the primary circulation return pipe of the primary anoxic tank (81) via a return pump. The permeate outlet of the primary MBR membrane in the primary membrane tank (83) is connected to the secondary MBR membrane via a water pump. A secondary inlet pipe is installed on the primary anoxic tank (84), and a secondary circulation return pipe is installed on the secondary anoxic tank (84). The bottom of the secondary anoxic tank (84) is connected to the bottom of the secondary aerobic tank (85). The outlet of the secondary aerobic tank (85) is connected to the inlet of the secondary membrane tank (86). The circulation outlet at the bottom of the secondary membrane tank (86) is connected to the secondary circulation return pipe of the secondary anoxic tank (84) through a return pump. The permeate outlet of the secondary MBR membrane in the secondary membrane tank (86) is connected to the inlet of the coagulation reaction sedimentation tank. The air compressor's output port is connected to the jet aerator in the primary aerobic tank (82), the jet aerator in the secondary aerobic tank (85), the aerator located below the primary MBR membrane in the primary membrane tank (83), and the aerator located below the secondary MBR membrane in the secondary membrane tank (86), respectively. The bottom of the primary aerobic tank (82) is connected to the inlet of the primary aerobic tank pump, and the outlet of the primary aerobic tank pump is connected to the jet aerator in the primary aerobic tank (82) through a pipeline. The bottom of the secondary aerobic tank (85) is connected to the inlet of the secondary aerobic tank pump, and the outlet of the secondary aerobic tank pump is connected to the jet aerator in the secondary aerobic tank (85) through a pipeline.

8. The anaerobic fermentation biogas slurry treatment system for fruit and vegetable waste according to claim 1, characterized in that, The coagulation reaction sedimentation tank includes a reaction tank and a sedimentation tank. The reaction tank includes a first reaction tank, a second reaction tank, and a third reaction tank connected in series. The inlet of the first reaction tank serves as the inlet of the coagulation reaction sedimentation tank, and the outlet of the third reaction tank is connected to the sedimentation tank. Potassium ferrate or an adsorbent is added to the first reaction tank, polyferric chloride or polyaluminum chloride is added to the second reaction tank, and a flocculant is added to the third reaction tank.

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