A complete set of kitchen waste treatment device and treatment method

Abstract

The present invention relates to a complete set of kitchen waste treatment equipment and treatment method, the equipment comprises a garbage pool, a slurry pool, a clear liquid pool and a residue pool, a grab bucket driving mechanism and a crusher are arranged near the garbage pool, the material can enter the slurry pool after being crushed by the crusher, the slurry pool is connected to a first feed pump, a first fermentation tank, a second feed pump and a second fermentation tank in sequence through a feed pipeline, the bottoms of the first and second fermentation tanks are respectively connected to the feed port at the top of the extruder, the liquid phase outlet of the extruder is connected to the clear liquid pool, the extruded residue of the extruder can be sent to the residue pool, the liquid phase outlet of the second fermentation tank is connected to the clear liquid pool, and the gas phase outlet of the second fermentation tank is connected to a biogas storage tank. The advantages are that the pre-treated kitchen waste can be converted into clear liquid with COD reaching the standard and biogas with high added value after crushing, slurry mixing and two fermentations, the complete set of equipment has good integrity, small footprint and is easy to install and maintain, has high kitchen waste treatment efficiency, and is suitable for industrial promotion and use.

Description

Technical Field

[0001] The present invention relates to the field of garbage disposal, and in particular to a complete set of kitchen waste disposal equipment and a disposal method. Background Art

[0002] Kitchen waste is part of urban domestic waste, which refers to the scraps and leftovers discarded from daily cooking in thousands of households, including leftovers, leftover rice, vegetable leaves, fruit peels, eggshells, etc. In addition, expired food, rotten fruits and vegetables, withered flowers and plants, and household potted plants are also part of kitchen waste, that is, the wet garbage that every household must sort out when some areas implement garbage sorting requirements. The biggest difference between kitchen waste and restaurant waste is that the oil content is relatively less and the risk to the environment is relatively smaller, but the amount of garbage is larger and contains a large amount of organic nutrients.

[0003] At present, a relatively simple single-phase anaerobic fermentation process is mostly used for kitchen waste treatment. The digestion reaction is carried out in a fermentation tank. The fermented organic matter is converted into biogas and the wastewater is directly discharged. However, its stability is poor, the biogas production is unstable and the fermentation speed is relatively slow. It is not suitable for industrial treatment and resource utilization of kitchen waste on a certain scale. Summary of the invention

[0004] The present invention provides a complete set of equipment and a method for treating kitchen waste, aiming to provide a complete set of equipment and a method suitable for large-scale treatment of kitchen waste with fast fermentation speed and stable biogas output.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: a complete set of kitchen waste treatment equipment, which includes a garbage pool for storing pre-treated kitchen waste, a slurry pool for preparing garbage slurry for fermentation, a clear liquid pool for storing clear liquid produced after fermentation, and a residue pool for collecting solid residues after fermentation. A grab bucket driving mechanism and a crusher are arranged near the garbage pool. The grab bucket driving mechanism can grab the garbage in the garbage pool and put it into the feed hopper of the crusher. The discharge port of the crusher sends the crushed material into the slurry pool through a first screw conveyor. The slurry pool is connected to a first feed pump, a first feed pump and a first feed pump in sequence through a feed pipeline. A fermentation tank, a second feed pump and a second fermentation tank, the bottom solid phase outlets of the first fermentation tank and the second fermentation tank are respectively connected to the feed port at the top of the extruder through the second screw conveyor and the third screw conveyor, the liquid phase outlet of the extruder is connected to the clear liquid tank through a pipeline, the solid phase outlet of the extruder is connected to the residue tank through a fourth screw conveyor, the liquid phase outlet of the second fermentation tank is connected to the clear liquid tank through a clear liquid collecting pipeline, the gas phase outlet of the second fermentation tank is connected to the biogas storage tank through a gas collecting pipeline, the clear liquid tank is connected to the slurry tank through a clear liquid recycling pipeline, and a water pump is provided on the clear liquid recycling pipeline.

[0006] Based on the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, the first fermentation tank and the second fermentation tank are connected via a return and adjustment pipeline so that the fermentation liquid in the second fermentation tank can be returned to the first fermentation tank to adjust the pH value in the first fermentation tank.

[0008] The advantage of adopting the above further structural improvement is that by utilizing the material transfer in the two fermentation tanks, the fermentation liquid with increased pH during the fermentation in the second fermentation tank is rationally utilized to neutralize the acidity of the solution in the first fermentation tank, which can effectively improve the efficiency of hydrolysis and acidification of the slurry in the first fermentation tank.

[0009] Furthermore, the lower middle part and the upper part of the first fermentation tank are connected through a first circulation pipeline, the first circulation pipeline is provided with a first circulation pump and a pH adjustment tank, the pH adjustment tank is arranged on the output side of the first circulation pump, the return and blending pipeline is connected with the first circulation pipeline, and the return and blending pipeline and the first circulation pipeline are respectively provided with independent stop valves.

[0010] The advantage of adopting the above-mentioned further structural improvement is that the first circulation pipeline pumps out the fermentation liquid in the middle and lower part of the first fermentation tank and then returns it to the upper part of the first fermentation tank, forming a circulating flow of the fermentation liquid, which plays the purpose of stirring mass transfer and making the fermentation colony more uniform, thereby improving the hydrolysis and acidification efficiency. During the circulation process, alkaline substances are added through the pH adjustment tank to make the fermentation liquid close to neutral so as to complete the hydrolysis and acidification of organic matter in the slurry more quickly.

[0011] Furthermore, the lower middle portion and the upper portion of the second fermentation tank are connected through a second circulation pipeline, and a second circulation pump is provided on the second circulation pipeline.

[0012] The advantage of adopting the above further structural improvement is that the second circulation pipeline and the second circulation pump can make the raw materials in the second fermentation tank circulate, thereby improving the efficiency of producing biogas by fermentation.

[0013] Furthermore, the clear liquid collecting pipeline is connected with the second circulation pipeline and the connection point is located at the output side of the second circulation pump. The clear liquid collecting pipeline and the second circulation pipeline are respectively provided with independent stop valves.

[0014] The advantage of adopting the above further structural improvement is that the second circulation pump can not only circulate the raw materials in the second fermentation tank, but also discharge the raw materials to the outside after the COD of the raw materials is fermented to below the set value and becomes clear liquid.

[0015] Furthermore, the gas collection pipeline is provided with a gas delivery pump and a one-way check valve for one-way ventilation to the biogas storage tank.

[0016] The advantage of adopting the above further structural improvement is that the biogas generated in the second fermentation tank is pressurized and stored in the biogas tank, thereby preventing the biogas from accumulating in the second fermentation tank and causing danger due to excessive pressure.

[0017] Furthermore, the grab bucket driving mechanism includes a crown crane, a sling and an electric hydraulic grab bucket.

[0018] The advantage of adopting the above-mentioned further structural improvement is that it ensures the smooth transportation of kitchen waste to the crusher and saves manpower; the grab bucket driving mechanism of the above-mentioned structure is easy to install, maintain and operate.

[0019] Furthermore, a leachate guide plate is provided between the garbage pit and the crusher feed hopper. The leachate guide plate is in an inverted V shape to guide the garbage leachate dripping when the electric hydraulic grab is lifted and moved between the garbage pit and the crusher to the garbage pit or the crusher feed hopper.

[0020] The advantage of adopting the above-mentioned further structural improvement is that it prevents the leachate or garbage fragments dripping when the grab bucket moves from polluting the ground between the garbage pool and the crusher.

[0021] Furthermore, the clear liquid recycling pipeline is also connected to the municipal sewage pipeline and the connection point is located at the output side of the water pump. The clear liquid recycling pipeline and the municipal sewage pipeline are respectively provided with independent stop valves.

[0022] The advantage of adopting the above further structural improvement is that the clear liquid can be reused or directly discharged through the municipal sewage pipeline.

[0023] The present invention also provides a method for treating kitchen waste, which uses the above-mentioned complete set of equipment to treat kitchen waste, and comprises the following steps:

[0024] S1. Put the pre-treated food waste into the garbage pool after bag breaking and screening, start the grab bucket driving mechanism to grab the food waste in the garbage pool and put it into the crusher feed hopper, start the crusher to break the food waste and send it into the slurry pool by the first screw conveyor;

[0025] S2. The tap water or clear liquid stored in the clear liquid tank is sent into the slurry tank through the clear liquid recycling pipeline to prepare a slurry with a set solid content, and then the prepared slurry is sent to the first fermentation tank through the first feed pump. After fermentation for a period of time, the fermentation liquid in the first fermentation tank is gradually pumped into the second fermentation tank through the second feed pump. At the same time, the first feed pump replenishes the slurry into the first fermentation tank. When the materials in the first fermentation tank and the second fermentation tank are fermented, the first circulation pump and the second circulation pump can be respectively turned on to circulate and stir the materials in the tanks. When the materials in the first fermentation tank are circulated and stirred, the pH of the materials can be adjusted to neutral through the pH adjustment tank. When adjusting the pH, the materials in the second fermentation tank can be sent to the second fermentation tank through the return and blending pipeline to increase the alkalinity of the materials in the first fermentation tank;

[0026] S3. During the fermentation process, the second fermentation tank continuously pumps the biogas in the tank into the biogas storage tank through the gas delivery pump. When the COD of the material in the second circulation pipeline is detected to be below the set value, the upper clear liquid in the second fermentation tank is discharged into the clear liquid tank through the clear liquid recovery pipeline;

[0027] S4. During the fermentation process, the inorganic residues deposited at the bottom of the first fermentation tank and the second fermentation tank are regularly discharged into the extruder through the second screw conveyor and the third screw conveyor. After extrusion by the extruder, the extruded liquid enters the clear liquid pool, and the remaining solid residue is sent to the residue pool by the fourth screw conveyor. The residue in the residue pool is finally transported out by the residue truck for landfill.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention provides a complete set of equipment for treating kitchen waste, which can transform pretreated kitchen waste into clear liquid with COD content reaching the emission standard and biogas with high added value after crushing, slurry adjustment and two fermentations. The complete set of equipment has good systematization, small footprint and is easy to install and maintain, has high kitchen waste treatment efficiency and is suitable for industrial promotion and use; the first fermentation is hydrolysis and acidification, the second fermentation is methane fermentation, the first fermentation product is the raw material for the second fermentation and the fermentation liquid with relatively large alkalinity generated during the second fermentation can be returned to the first fermentation tank to increase the pH value to improve the fermentation efficiency; the clear liquid generated after the second fermentation is completed can be used to mix with the crushed kitchen waste to prepare slurry, saving tap water consumption and lowering the overall cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of a kitchen waste treatment device provided by the present invention.

[0031] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0032] 1. Garbage pool; 2. Slurry pool; 3. Clear liquid pool; 4. Residue pool; 5. Grab bucket driving mechanism; 6. Crusher; 7. First screw conveyor; 8. First feed pump; 9. First fermentation tank; 10. Second feed pump; 11. Second fermentation tank; 12. Second screw conveyor; 13. Third screw conveyor; 14. Extruder; 15. Fourth screw conveyor; 16. Clear liquid collection pipeline; 17. Gas collection pipeline; 18. Biogas storage tank; 19. Clear liquid reuse pipeline; 20. Water pump; 21. Return and blending pipeline; 22. First circulation pump; 23. pH adjustment tank; 24. Second circulation pump; 25. Gas delivery pump; 26. Leachate guide plate. DETAILED DESCRIPTION

[0033] The principles and features of the present invention are described below in conjunction with the accompanying drawings and specific embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0034] In the description of the present invention, if terms indicating orientation such as "up", "down", "left", "right", "top", "bottom", "inside" and "outside" are used, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0035] like Figure 1As shown, the present invention provides a complete set of kitchen waste treatment equipment, which includes a garbage pool 1 for storing pre-treated kitchen waste, a slurry pool 2 for preparing garbage slurry for fermentation, a clear liquid pool 3 for storing clear liquid produced after fermentation, and a residue pool 4 for collecting solid residues after fermentation. A grab bucket driving mechanism 5 and a crusher 6 are arranged near the garbage pool 1. The grab bucket driving mechanism 5 can grab the garbage in the garbage pool 1 and put it into the feed hopper of the crusher 6. The discharge port of the crusher 6 feeds the crushed material into the slurry pool 2 through a first screw conveyor 7. The slurry pool 2 is connected to a first feed pump 8, a first fermentation tank 9, a second feed pump 10 and a second fermentation tank in sequence through a feed pipeline. 11, the bottom solid phase outlets of the first fermentation tank 9 and the second fermentation tank 11 are connected to the feed port at the top of the extruder 14 through the second screw conveyor 12 and the third screw conveyor 13 respectively, the liquid phase outlet of the extruder 14 is connected to the clear liquid tank 3 through a pipeline, the solid phase outlet of the extruder 14 is connected to the residue tank 4 through the fourth screw conveyor 15, the liquid phase outlet of the second fermentation tank 11 is connected to the clear liquid tank 3 through a clear liquid collecting pipeline 16, the gas phase outlet of the second fermentation tank 11 is connected to the biogas storage tank 18 through a gas collecting pipeline 17, the clear liquid tank 3 is connected to the slurry tank 2 through a clear liquid recycling pipeline 19, and a water pump 20 is provided on the clear liquid recycling pipeline 19.

[0036] It should be noted that the crusher and the screw conveyors can be purchased on the market. The bottom of the first and second fermentation tanks are preferably designed to be funnel-shaped and a solid phase outlet for discharging residues is provided at the lower end.

[0037] In a preferred embodiment of the present invention, the first fermentation tank 9 and the second fermentation tank 11 are also connected via a return and adjustment pipeline 21 to return the fermentation liquid in the second fermentation tank 11 to the first fermentation tank 9 to adjust the pH value in the first fermentation tank 9.

[0038] On the basis of the above structure, another preferred embodiment of the present invention is that the middle and lower parts of the first fermentation tank 9 are connected with the upper parts through a first circulation pipe, and the first circulation pipe is provided with a first circulation pump 22 and a pH adjustment tank 23, and the pH adjustment tank 23 is arranged on the output side of the first circulation pump 22, and the return and blending pipe 21 is connected with the first circulation pipe, and the return and blending pipe 21 and the first circulation pipe are respectively provided with independent stop valves.

[0039] It should be noted that the return and blending pipeline may not be connected to the first circulation pipeline, but may be a pipeline independent of the first circulation pipeline. A liquid pump for returning the slurry in the second fermentation tank to the first fermentation tank is separately provided on the return and blending pipeline.

[0040] A preferred embodiment of the present invention is that the lower middle portion and the upper portion of the second fermentation tank 11 are connected via a second circulation pipeline, and a second circulation pump 24 is provided on the second circulation pipeline.

[0041] A preferred embodiment of the present invention is that the clear liquid collecting pipe 16 is connected to the second circulation pipe and the connection point is located at the output side of the second circulation pump 24, and the clear liquid collecting pipe 16 and the second circulation pipe are respectively provided with independent stop valves.

[0042] A preferred embodiment of the present invention is that the gas collection pipeline 17 is provided with a gas delivery pump 25 and a one-way check valve for one-way ventilation to the biogas storage tank 18 .

[0043] A preferred embodiment of the present invention is that the grab bucket driving mechanism 5 includes a crown crane, a sling and an electric hydraulic grab bucket.

[0044] It should be noted that the overhead crane can travel on the horizontal track of the gantry, and an electric hoist is provided on the overhead crane to retract and release the sling.

[0045] A preferred embodiment of the present invention is that a leachate guide plate 26 is further provided between the garbage pit 1 and the feed hopper of the crusher 6, and the leachate guide plate 26 is in an inverted V shape to guide the garbage leachate dripping when the electric hydraulic grab is lifted and moved between the garbage pit 1 and the crusher 6 to the garbage pit 1 or the feed hopper of the crusher 6.

[0046] A preferred embodiment of the present invention is that the clean liquid recycling pipeline 19 is also connected to the municipal sewage pipeline and the connection point is located at the output side of the water pump 20, and the clean liquid recycling pipeline 19 and the municipal sewage pipeline are respectively provided with independent stop valves.

[0047] The steps of processing kitchen waste by the above-mentioned complete set of equipment are as follows:

[0048] S1. Put the pre-processed food waste into the garbage pool 1, start the grab bucket driving mechanism 5 to grab the food waste in the garbage pool 1 and put it into the feed hopper of the crusher 6, start the crusher 6 to break the food waste into 15-25mm strips or granules and send it into the slurry pool 2 by the first screw conveyor 7;

[0049] S2. The tap water or clear liquid stored in the clear liquid tank 3 is sent to the slurry tank 2 through the clear liquid recycling pipeline 19 to prepare a slurry with a set solid content (whose COD value is about 8-12g / L), and then the prepared slurry is sent to the first fermentation tank 9 through the first feed pump 8. After a period of fermentation (5d), the fermentation liquid in the first fermentation tank 9 is gradually pumped into the second fermentation tank 11 through the second feed pump 10 (flow rate 200-300L / 2d). At the same time, the first feed pump 8 replenishes the slurry to the first fermentation tank 9 (flow rate 200-300L / 2d). ), during normal production, feeding and discharging are continuously performed, when the materials in the first fermentation tank 9 and the second fermentation tank 11 are fermented, the first circulation pump 22 and the second circulation pump 24 can be respectively turned on to circulate and stir the materials in the tanks, when the materials in the first fermentation tank 9 are circulated and stirred, the pH of the materials can be adjusted to neutral through the pH adjustment tank 23, when the pH is adjusted, the materials in the second fermentation tank 11 can be sent to the second fermentation tank 11 through the return blending pipeline 21 to increase the alkalinity of the materials in the first fermentation tank 9 (the amount of the return can be adjusted arbitrarily within the range of 0-50L / d as needed);

[0050] S3. During the fermentation process, the second fermentation tank 11 continuously pumps the biogas in the tank into the biogas storage tank 18 through the gas delivery pump 25 for storage. When the COD of the material in the second circulation pipeline is detected to be below the set value (80 mg / L), the upper clear liquid in the second fermentation tank 11 is discharged into the clear liquid tank 3 through the clear liquid recovery pipeline;

[0051] S4. During the fermentation process, the inorganic residues deposited at the bottom of the first fermentation tank 9 and the second fermentation tank 11 are regularly discharged into the extruder 14 through the second screw conveyor 12 and the third screw conveyor 13. After being extruded by the extruder 14, the extruded liquid enters the clear liquid pool 3, and the remaining solid residue is sent to the residue pool 4 by the fourth screw conveyor 15. The residue in the residue pool 4 is finally transported out by the residue transport vehicle for landfill.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A complete set of kitchen waste treatment equipment, characterized in that: The invention comprises a garbage pool (1) for storing pre-treated kitchen waste, a slurry pool (2) for preparing garbage slurry for fermentation, a clear liquid pool (3) for storing clear liquid produced after fermentation, and a residue pool (4) for collecting solid residues after fermentation. A grab bucket driving mechanism (5) and a crusher (6) are arranged near the garbage pool (1). The grab bucket driving mechanism (5) can grab the garbage in the garbage pool (1) and put it into the feed hopper of the crusher (6). The discharge port of the crusher (6) feeds the crushed material into the slurry pool (2) through a first screw conveyor (7). The slurry pool (2) is connected to a first feed pump (8), a first fermentation tank (9), a second feed pump (10) and a second fermentation tank (11) in sequence through a feed pipeline. The first fermentation tank (9) and The solid phase outlet at the bottom of the second fermentation tank (11) is connected to the feed port at the top of the extruder (14) through a second screw conveyor (12) and a third screw conveyor (13), respectively; the liquid phase outlet of the extruder (14) is connected to the clear liquid tank (3) through a pipeline; the solid phase outlet of the extruder (14) is connected to the residue tank (4) through a fourth screw conveyor (15); the liquid phase outlet of the second fermentation tank (11) is connected to the clear liquid tank (3) through a clear liquid collecting pipeline (16); the gas phase outlet of the second fermentation tank (11) is connected to a biogas storage tank (18) through a gas collecting pipeline (17); the clear liquid tank (3) is connected to the slurry tank (2) through a clear liquid recycling pipeline (19); and a water pump (20) is provided on the clear liquid recycling pipeline (19).

2. A kitchen waste treatment device according to claim 1, characterized in that: The first fermentation tank (9) and the second fermentation tank (11) are also connected via a return and adjustment pipeline (21) to return the fermentation liquid in the second fermentation tank (11) to the first fermentation tank (9) to adjust the pH value in the first fermentation tank (9).

3. A kitchen waste treatment device according to claim 2, characterized in that: The middle and lower parts of the first fermentation tank (9) are connected to each other through a first circulation pipeline, and a first circulation pump (22) and a pH adjustment tank (23) are provided on the first circulation pipeline. The pH adjustment tank (23) is arranged on the output side of the first circulation pump (22). The return and blending pipeline (21) is connected to the first circulation pipeline, and the return and blending pipeline (21) and the first circulation pipeline are respectively provided with independent stop valves.

4. The kitchen waste treatment device according to claim 1, characterized in that: The middle and lower parts of the second fermentation tank (11) are connected with the upper part through a second circulation pipeline, and a second circulation pump (24) is provided on the second circulation pipeline.

5. A kitchen waste treatment device according to claim 4, characterized in that: The clear liquid collection pipeline (16) is connected to the second circulation pipeline, and the connection point is located at the output side of the second circulation pump (24). The clear liquid collection pipeline (16) and the second circulation pipeline are respectively provided with independent stop valves.

6. The kitchen waste treatment device according to claim 1, characterized in that: The gas collection pipeline (17) is provided with a gas delivery pump (25) and a one-way check valve for one-way ventilation to the biogas storage tank (18).

7. The kitchen waste treatment device according to claim 1, characterized in that: The grab bucket driving mechanism (5) comprises a crown crane, a sling and an electric hydraulic grab bucket.

8. A kitchen waste treatment device according to claim 7, characterized in that: A leachate guide plate (26) is also provided between the garbage pit (1) and the crusher (6) feed hopper. The leachate guide plate (26) is in an inverted V shape so as to guide the garbage leachate dripping when the electric hydraulic grab bucket is lifted and moved between the garbage pit (1) and the crusher (6) to the garbage pit (1) or the crusher (6) feed hopper.

9. A kitchen waste treatment device according to any one of claims 1 to 8, characterized in that: The clean liquid recycling pipeline (19) is also connected to the municipal sewage pipeline and the connection point is located at the output side of the water pump (20). The clean liquid recycling pipeline (19) and the municipal sewage pipeline are respectively provided with independent stop valves.

10. A method for treating kitchen waste, characterized in that: The kitchen waste treatment is carried out by the complete set of apparatus as claimed in any one of claims 1 to 9, comprising the following steps: S1. Put the food waste after bag breaking and screening pretreatment into the garbage pool (1), start the grab bucket driving mechanism (5) to grab the food waste in the garbage pool (1) and put it into the feed hopper of the crusher (6), start the crusher (6) to break the food waste and send it into the slurry pool (2) through the first screw conveyor (7); S2. The tap water or clear liquid stored in the clear liquid tank (3) is fed into the slurry tank (2) through the clear liquid recycling pipeline (19) to prepare a slurry with a set solid content, and then the prepared slurry is fed into the first fermentation tank (9) through the first feed pump (8). After a period of fermentation, the fermentation liquid in the first fermentation tank (9) is gradually pumped into the second fermentation tank (11) through the second feed pump (10). At the same time, the first feed pump (8) replenishes the slurry into the first fermentation tank (9). When the materials in the first fermentation tank (9) and the second fermentation tank (11) are fermented, the first circulation pump (22) and the second circulation pump (24) are respectively turned on to circulate and stir the materials in the tanks. When the materials in the first fermentation tank (9) are circulated and stirred, the pH of the materials is adjusted to neutral through the pH adjustment tank (23). When adjusting the pH, the materials in the second fermentation tank (11) are fed into the second fermentation tank (11) through the return and blending pipeline (21) to increase the alkalinity of the materials in the first fermentation tank (9); S3. During the fermentation process, the second fermentation tank (11) continuously pumps the biogas in the tank into the biogas storage tank (18) through the gas delivery pump (25) for storage. When the COD of the material in the second circulation pipeline is detected to be below the set value, the upper clear liquid in the second fermentation tank (11) is discharged into the clear liquid tank (3) through the clear liquid recovery pipeline; S4. During the fermentation process, the inorganic residues deposited at the bottom of the first fermentation tank (9) and the second fermentation tank (11) are regularly discharged into the extruder (14) through the second screw conveyor (12) and the third screw conveyor (13). After being extruded by the extruder (14), the extruded liquid enters the clear liquid pool (3), and the remaining solid residue is sent to the residue pool (4) by the fourth screw conveyor (15). The residue in the residue pool (4) is finally transported out by a slag truck for landfill.

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