A solid-liquid separation device for anaerobic digester of kitchen waste liquid

Abstract

This utility model discloses an anaerobic digester for food waste, relating to the field of food waste solid-liquid separation technology. It includes a fully mixed anaerobic reactor connected to the effluent of a pretreatment system for anaerobic digestion of organic matter and methanogenesis in the food waste waste. The fully mixed anaerobic reactor is connected to a membrane tank for collecting and separating the sludge-water mixture. The membrane tank is connected to a return pump via a degassing tank, and the return pump is connected to the fully mixed anaerobic reactor. Multiple microfiltration membrane modules for sludge-water separation are installed in the membrane tank. These microfiltration membrane modules are connected to a water pump and a blower. The water pump is connected to a product water tank, and a chemical injection assembly is installed on the pipeline connecting the water pump and the product water tank. The product water tank is connected to a biochemical system. This utility model not only provides sufficient time for the slow-growing methanogenic bacteria to proliferate and for solid decomposition in the fully mixed anaerobic reactor, but also effectively achieves sludge-water separation in the digester.

Description

Technical Field

[0001] This utility model relates to the field of solid-liquid separation technology of kitchen waste, and in particular to a solid-liquid separation device for anaerobic digester liquid of kitchen waste. Background Technology

[0002] Food waste treatment mainly includes three key links: solid-liquid separation, waste liquid treatment, and resource utilization. Among them, food waste waste liquid is characterized by high concentrations of COD, suspended solids, and BOD, and belongs to high-concentration organic wastewater. The general treatment process is as follows: the waste liquid is first subjected to anaerobic fermentation, and the fermentation biogas slurry then enters the subsequent sewage treatment system for deep biochemical treatment.

[0003] In practical applications, anaerobic treatment systems often suffer from insufficient volumetric load, low organic matter removal efficiency, and incomplete solid-liquid separation of biogas slurry and biogas residue. This results in wastewater with excessively high suspended solids (SS) directly entering the downstream biological treatment system, leading to problems such as high operating load, high operating costs, and a huge amount of residual sludge production in the biological treatment system.

[0004] To address the above problems, common engineering solutions include: (1) adding a secondary anaerobic system and using it in series to ensure the removal rate of the anaerobic system; (2) modifying and expanding the original anaerobic system, increasing the volume of the anaerobic reactor, and increasing the retention time to improve the removal rate of the system.

[0005] However, the above solutions mainly focus on increasing the pool capacity. The problems are that expanding the pool capacity requires a large investment in infrastructure and a large increase in land area, which is not conducive to the renovation and use of old treatment plants with limited land and investment.

[0006] Therefore, there is an urgent need for an anaerobic digester for food waste liquid solid-liquid separation device that can provide sufficient time for the proliferation of slow-growing methanogenic bacteria and the decomposition of solids without expanding the digester volume, thereby improving methanogenic efficiency, shortening HRT, and significantly increasing treatment capacity. It can also effectively solve the problems of incomplete separation of mud and water in digester liquid, which leads to excessive SS and COD entering the downstream biological treatment system, resulting in high system operating load and high energy consumption. Utility Model Content

[0007] The purpose of this invention is to provide a solid-liquid separation device for anaerobic digester liquid from kitchen waste, so as to solve the problems existing in the prior art.

[0008] To achieve the above objectives, this utility model provides the following solution: This utility model provides a solid-liquid separation device for anaerobic digestion of kitchen waste liquid, including a fully mixed anaerobic reactor connected to the effluent end of a pretreatment system for anaerobic digestion of organic matter and methanogenesis of kitchen waste liquid. The effluent end of the fully mixed anaerobic reactor is connected to the inlet end of a membrane tank for collecting and separating the mud-water mixture in the effluent end of the fully mixed anaerobic reactor. The effluent end of the membrane tank is connected to the inlet end of a return pump through a degassing tank. The effluent end of the return pump is connected to the fully mixed anaerobic reactor. The membrane tank is equipped with multiple microfiltration membrane modules for mud-water separation. The multiple microfiltration membrane modules are connected to a water pump and a blower. The effluent end of the water pump is connected to a product water tank. A chemical injection assembly is installed on the pipeline connecting the water pump and the product water tank. The effluent end of the product water tank is connected to a biochemical system.

[0009] Preferably, the fully mixed anaerobic reactor is equipped with an anaerobic reactor stirrer for stirring the food waste liquid inside the fully mixed anaerobic reactor.

[0010] Preferably, the degassing tank is equipped with a degassing tank agitator for stirring the mud-water mixture.

[0011] Preferably, multiple microfiltration membrane modules are installed inside the membrane tank.

[0012] Preferably, the water pump and the blower are connected to the top of the microfiltration membrane module.

[0013] Preferably, the water pump is a cam pump capable of both forward and reverse rotation.

[0014] Preferably, the inlet of the reflux pump is connected to the degassing tank, and the outlet of the reflux pump is connected to the fully mixed anaerobic reactor.

[0015] Preferably, the dosing assembly includes a sodium hypochlorite dosing tank for storing sodium hypochlorite and an acid dosing tank for storing acid.

[0016] Preferably, the sodium hypochlorite dosing tank is connected to the water pump and the product water tank via a pipeline through a sodium hypochlorite dosing pump.

[0017] Preferably, the acid dosing tank is connected to the water pump and the product water tank via a pipeline through an acid dosing pump.

[0018] The present invention discloses the following technical effects:

[0019] This invention utilizes a fully mixed anaerobic reactor to perform anaerobic digestion of organic matter and methanogenesis in kitchen waste liquid. Then, the sludge is separated into mud and water through a membrane tank and a microfiltration membrane module. The separated sludge is then further treated through a water production tank and a biochemical system. Meanwhile, the mud-water mixture in the membrane tank is returned to the fully mixed anaerobic reactor for recycling via a return pump.

[0020] This invention can provide sufficient time for the proliferation of slow-growing methanogenic bacteria and the decomposition of solids in a fully mixed anaerobic reactor without expanding the tank volume, thereby improving methanogenic efficiency, shortening HRT, and significantly increasing treatment capacity. It can also effectively solve the problems of incomplete separation of mud and water in biogas slurry, which leads to excessive SS and COD entering the downstream biological treatment system, resulting in high system operating load and high energy consumption. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present utility model;

[0023] Figure 2 This is a system flowchart of Embodiment 2 of the present invention;

[0024] The components include: 1. Fully mixed anaerobic reactor; 1-1. Anaerobic reactor agitator; 2. Reflux pump; 3. Degassing tank; 3-1. Degassing tank agitator; 4. Membrane tank; 4-1. Microfiltration membrane module; 5. Water pump; 6. Product water tank; 7. Biochemical system; 8. Blower; 9. Sodium hypochlorite dosing tank; 10. Sodium hypochlorite dosing pump; 11. Acid dosing tank; 12. Acid dosing pump. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] Reference Figure 1 This utility model discloses a solid-liquid separation device for anaerobic digester of kitchen waste liquid, including a fully mixed anaerobic reactor 1 connected to the effluent end of a pretreatment system for anaerobic digestion of organic matter and methanogenesis of kitchen waste liquid. The effluent end of the fully mixed anaerobic reactor 1 is connected to the inlet end of a membrane tank 4 for collecting and separating the mud-water mixture in the effluent end of the fully mixed anaerobic reactor 1. The effluent end of the membrane tank 4 is connected to the inlet end of a return pump 2 through a degassing tank 3. The effluent end of the return pump 2 is connected to the fully mixed anaerobic reactor 1. Multiple microfiltration membrane modules 4-1 for mud-water separation are installed in the membrane tank 4. Multiple microfiltration membrane modules 4-1 are connected to a water pump 5 and a blower 8. The effluent end of the water pump 5 is connected to a product water tank 6. A chemical injection assembly is installed on the pipeline connecting the water pump 5 and the product water tank 6. The effluent end of the product water tank 6 is connected to a biochemical system 7.

[0029] The product water tank 6 can be in the form of a reinforced concrete structure or a prefabricated tank structure. The product water tank 6 mainly serves as the product water tank for the microfiltration membrane system, while also functioning as the backwash water intake tank for the membrane system and as an intermediate water tank for wastewater to enter the subsequent biochemical system 7.

[0030] The form of the biological system 7 can be a reinforced concrete structure or a prefabricated tank structure; its main function is to use different types of microorganisms in the anaerobic, anoxic and aerobic units inside the biological system 7 to complete reactions such as hydrolysis acidification, organic matter oxidation, nitrification and denitrification using the organic and inorganic components in the wastewater, thereby achieving the removal of various pollutants in the wastewater.

[0031] This invention utilizes a fully mixed anaerobic reactor 1 to perform anaerobic digestion of organic matter and methanogenesis in kitchen waste liquid. Then, the slurry is separated into mud and water through a microfiltration membrane module 4-1 in a membrane tank 4. The separated slurry is then further treated in a water production tank 6 and a biochemical system 7. Meanwhile, the mud-water mixture in the membrane tank 4 is returned to the fully mixed anaerobic reactor 1 for recycling via a return pump 2.

[0032] This invention can provide sufficient time for the proliferation of slow-growing methanogenic bacteria and the decomposition of solids in the fully mixed anaerobic reactor 1 without expanding the tank volume, thereby improving methanogenic efficiency, shortening HRT, and significantly increasing treatment capacity; it can also effectively solve the problems of incomplete separation of mud and water in biogas slurry, which leads to excessive SS and COD entering the downstream biological system, causing high system operating load and high energy consumption.

[0033] To further optimize the design, an anaerobic reactor agitator 1-1 is installed on the fully mixed anaerobic reactor 1 to stir the food waste liquid inside the reactor 1. The agitator 1-1 stirs the food waste liquid inside the fully mixed anaerobic reactor 1, enabling effective anaerobic digestion of organic matter and methanogenesis.

[0034] The fully mixed anaerobic reactor 1 is a fully mixed anaerobic reactor. This reactor utilizes the metabolic activities of anaerobic microorganisms to degrade organic matter, including hydrolysis, acidification, and methanogenesis. The fully mixed anaerobic reactor operates with continuous temperature control and continuous or semi-continuous feeding, making it suitable for treating high-concentration feedstocks containing large amounts of suspended solids.

[0035] In a fully mixed anaerobic reactor, the newly introduced raw materials are quickly mixed with all the fermentation broth during the fermentation period due to the stirring action, so that the concentration of the fermentation substrate is always kept at a relatively low level. The discharged broth has the same substrate concentration as the fermentation broth, and the microorganisms are also discharged together with the broth. Therefore, the discharge concentration is generally high.

[0036] This fully mixed anaerobic reactor is a typical digester with equal HRT (hydraulic retention time), SRT (slow retention time), and MRT. In order to maintain a balance between the proliferation of slow-growing methanogens and the flushing rate, a longer HRT is required, generally 10-15 days or longer.

[0037] To further optimize the design, a degassing tank agitator 3-1 is installed on the degassing tank 3 to stir the mud-water mixture. The degassing tank agitator 3-1 can effectively and thoroughly stir the mud-water mixture in the degassing tank 3.

[0038] The air in the mud-water mixture is released by the agitator 3-1 in the degassing tank 3, preventing it from flowing back into the fully mixed anaerobic reactor 1 and damaging the anaerobic environment.

[0039] To further optimize the design, multiple microfiltration membrane modules 4-1 are installed inside the membrane tank 4. These multiple microfiltration membrane modules 4-1 effectively achieve mud-water separation of the biogas slurry.

[0040] In a further optimized design, water pump 5 and blower 8 are connected to the top of microfiltration membrane module 4-1.

[0041] The microfiltration membrane module 4-1 is a wastewater filtration device composed of a metal frame, microfiltration membrane elements, aeration pipes, and product water pipes. It achieves the filtration and separation of mud-water mixtures through the linkage of water pump 5 suction, microfiltration membrane element filtration, and blower 8 aeration and scrubbing.

[0042] The waste liquid flowing into the membrane tank 4 is filtered through the microfiltration membrane module 4-1 by the suction action of the water pump 5 and the aeration and scrubbing of the blower 8.

[0043] To further optimize the design, water pump 5 adopts a cam pump capable of both forward and reverse rotation. The impeller of the cam pump rotates forward or in reverse via its motor.

[0044] When the water pump 5 rotates forward, it can transport the biogas slurry to the water production pond 6.

[0045] When the water pump 5 reverses, it can achieve backwashing of the microfiltration membrane in the microfiltration membrane module 4-1 from the inside out, avoiding the blockage of the product water membrane pores by pollutants.

[0046] The inlet of water pump 5 is connected to the product water outlets of multiple microfiltration membrane modules 4-1 via pipelines, and the outlet of water pump 5 is connected to the product water tank 6 via pipelines. The rotation of the motor drives the cam inside the pump chamber of water pump 5 to rotate, squeezing the water inside to flow out towards the outlet direction, while water simultaneously enters from the inlet direction, thus achieving the suction effect of the product water from the microfiltration membrane module 4-1. Reversing the motor enables the backwashing function of the product water on the microfiltration membrane module 4-1.

[0047] The outlet of blower 8 is connected to the air inlets of multiple microfiltration membrane modules 4-1 via pipelines. As the motor and blower impeller rotate, air is forced from the outlet of blower 8 into the air inlets of the multiple microfiltration membrane modules 4-1, and then released from the aerators at the bottom of the microfiltration membrane modules 4-1. In the water, the air rises in the form of bubbles, causing the membrane elements to vibrate during this process, thus preventing sludge from adhering to the membrane surface and clogging the membrane permeate channels.

[0048] Further optimization of the scheme: the inlet of the reflux pump 2 is connected to the degassing tank 3, and the outlet of the reflux pump 2 is connected to the fully mixed anaerobic reactor 1.

[0049] The reflux pump 2 can transport the mud-water mixture in the degassing tank 3 to the fully mixed anaerobic reactor 1.

[0050] The solution is further optimized so that the injection assembly includes a sodium hypochlorite dosing tank 9 for storing sodium hypochlorite and an acid dosing tank 11 for storing acid.

[0051] The scheme was further optimized by connecting the sodium hypochlorite dosing tank 9 to the water pump 5 and the product water tank 6 via the pipeline between the sodium hypochlorite dosing pump 10 and the water pump 5.

[0052] The scheme was further optimized so that the acid dosing tank 11 was connected to the water pump 5 and the product water tank 6 through the pipeline between the acid dosing pump 12 and the water pump 5.

[0053] By adding sodium hypochlorite or acid solution to the pipeline between water pump 5 and product water tank 6, the backwashing of the microfiltration membrane of microfiltration membrane module 4-1 can be completed more thoroughly, avoiding contaminants from clogging the product water membrane pores.

[0054] Working process: The kitchen waste liquid, which has undergone pretreatment and oil removal by the pretreatment system, first enters the fully mixed anaerobic reactor 1. Under the stirring action of the anaerobic reactor stirrer 1-1, the organic matter undergoes anaerobic digestion and methanogenesis. The mud-water mixture in the digestate after anaerobic digestion flows by gravity into the membrane tank 4. Under the suction action of the water pump 5 and the aeration and scrubbing action of the blower 8, the waste liquid is filtered by the microfiltration membrane module 4-1, and the digestate enters the water production tank 6. The mud-water mixture is retained in the membrane tank 4. The concentrated mud-water mixture in the membrane tank 4 is transported to the fully mixed anaerobic reactor 1 for further treatment by the return pump 2. After the liquid level in the water production tank 6 reaches the high level, it flows by gravity into the biological treatment system 7 for deep treatment. After treatment, it can effectively meet the emission standards.

[0055] After the membrane tank 4 has been running for a period of time, pollutants will adhere to the membrane surface and block the membrane pores, requiring backwashing to restore the membrane's water production channels. Pump 5 is a cam pump. The motor of the cam pump drives the impeller to reverse, continuously pumping the filtrate in the water production tank 6 into the water production pipeline of the microfiltration membrane module 4-1, realizing backwashing of the microfiltration membrane from the inside to the outside.

[0056] In actual operation, depending on the fouling of the microfiltration membrane, sodium hypochlorite or acid solution can be added to the backwash pipeline through sodium hypochlorite dosing tank 9, sodium hypochlorite dosing pump 10, acid dosing tank 11, and acid dosing pump 12 during the backwashing process to more thoroughly complete the backwashing of the microfiltration membrane.

[0057] Membrane tank 4 is operated in a sequence of 7 minutes of permeate production followed by 2 minutes of backwashing; the average operating flux is controlled at 8-16 LMH.

[0058] Example 2

[0059] Reference Figure 2 The difference between this embodiment and Embodiment 1 is that the membrane tank 4 and the microfiltration membrane module 4-1 in Embodiment 1 are replaced with anaerobic microfiltration membranes, and the blower 8 is removed, while other configurations remain unchanged.

[0060] The anaerobic microfiltration membrane in Example 2 is an external pressure microfiltration tube that primarily uses hydrostatic pressure to force water to flow by gravity through a semi-permeable membrane element. The main material is polyvinylidene fluoride (PVDF), with a membrane tube diameter of 10 mm and a filtration pore size of 50 nm. The anaerobic microfiltration membrane employs a cross-flow filtration method, allowing the material to flow through the inner surface of the membrane tube at high speed. The permeate is filtered through physical action and collected outside the tube, while the retained substances (suspended solid particles) are carried out of the membrane tube by the concentrate. This method can reduce pollution caused by high concentrations of materials.

[0061] This invention, applied to the solid-liquid separation of anaerobic digester slurry from kitchen waste, can solve the following problems:

[0062] (1) This utility model can achieve decoupled control of hydraulic retention time (HRT) and sludge retention time (SRT), which can make SRT reach several times that of traditional anaerobic digestion, providing sufficient time for the proliferation of slow-growing methanogenic bacteria and the decomposition of solids, thereby improving methanogenic efficiency. At the same time, it can shorten HRT and greatly improve the treatment capacity of the reactor.

[0063] (2) This utility model, through its mobile modular design, can be flexibly and dynamically combined according to different project scales and different land requirements to meet the transformation requirements.

[0064] (3) This utility model can effectively solve the problems of incomplete separation of mud and water in biogas slurry, resulting in excessive SS and COD entering the downstream biochemical system 7, causing high system operating load and high energy consumption.

[0065] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0066] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A solid-liquid separation device for anaerobic digester of kitchen waste liquid, characterized in that: The system includes a fully mixed anaerobic reactor (1) connected to the effluent of a pretreatment system for anaerobic digestion of organic matter and methanogenesis of kitchen waste liquid. The effluent of the fully mixed anaerobic reactor (1) is connected to the inlet of a membrane tank (4) for collecting and separating the mud-water mixture in the effluent of the fully mixed anaerobic reactor (1). The effluent of the membrane tank (4) is connected to the inlet of a return pump (2) through a degassing tank (3). The outlet end of the membrane tank (4) is connected to the fully mixed anaerobic reactor (1). Multiple microfiltration membrane modules (4-1) for mud-water separation are installed in the membrane tank (4). Multiple microfiltration membrane modules (4-1) are connected to a water pump (5) and a blower (8). The outlet end of the water pump (5) is connected to a product water tank (6). A chemical injection assembly is installed on the pipeline connecting the water pump (5) and the product water tank (6). The outlet end of the product water tank (6) is connected to a biochemical system (7).

2. The kitchen waste liquid-liquid separation device according to claim 1, characterized in that: The fully mixed anaerobic reactor (1) is equipped with an anaerobic reactor stirrer (1-1) for stirring the kitchen waste liquid inside the fully mixed anaerobic reactor (1).

3. The kitchen waste liquid-liquid separation device according to claim 1, characterized in that: The degassing tank (3) is equipped with a degassing tank agitator (3-1) for stirring the mud-water mixture.

4. The kitchen waste liquid-liquid separation device according to claim 1, characterized in that: Multiple microfiltration membrane modules (4-1) are installed inside the membrane tank (4).

5. The kitchen waste liquid-liquid separation device according to claim 1, wherein: The water pump (5) and the blower (8) are connected to the top of the microfiltration membrane module (4-1).

6. The kitchen waste liquid-liquid separation device according to claim 1, characterized in that: The water pump (5) is a cam pump capable of forward and reverse rotation.

7. The kitchen waste liquid-liquid separation device according to claim 1, characterized in that: The inlet of the reflux pump (2) is connected to the degassing tank (3), and the outlet of the reflux pump (2) is connected to the fully mixed anaerobic reactor (1).

8. The kitchen waste liquid-liquid separation device according to claim 1, characterized in that: The dosing assembly includes a sodium hypochlorite dosing tank (9) for storing sodium hypochlorite and an acid dosing tank (11) for storing acid.

9. The kitchen waste liquid-liquid separation device according to claim 8, characterized in that: The sodium hypochlorite dosing tank (9) is connected to the water pump (5) and the water production tank (6) via a pipeline through the sodium hypochlorite dosing pump (10).

10. The kitchen waste liquid-liquid separation device according to claim 8, characterized in that: The acid dosing tank (11) is connected to the water pump (5) and the water production tank (6) via the pipeline of the acid dosing pump (12).

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