A system and method for resource utilization of high-concentration organic kitchen waste water without anaerobic treatment

Abstract

The application discloses a system and process for high-concentration organic kitchen waste water anaerobic resource utilization, which comprises a first natural sedimentation tank and a second natural sedimentation tank arranged in parallel, wherein the first natural sedimentation tank is sequentially connected with an adjusting tank, a three-phase centrifuge, a first intermediate water tank, a membrane concentration system and a second intermediate water tank; the second natural sedimentation tank is sequentially connected with a sludge tank, a membrane grid and a third intermediate water tank; the bottom of the first natural sedimentation tank is connected with the sludge tank, and the top of the second natural sedimentation tank is connected with the adjusting tank; the water outlet of the third intermediate water tank is connected with the adjusting tank; the application can realize the separation of solid and water in the kitchen waste water by a physical method without adding any chemicals, and the separated solid can be used for insect breeding resource utilization without adding any chemicals; meanwhile, the separation process does not add any chemicals, so that the operation cost of pretreatment is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of kitchen wastewater treatment technology, specifically to a system and method for the non-anaerobic resource utilization of high-concentration organic kitchen wastewater. Background Technology

[0002] Food waste is a common type of waste in daily life. Many restaurants simply throw it away or have it collected by sanitation workers and then disposed of in landfills. However, food waste has other uses; it can be used to refine asphalt, biodiesel, and bio-fertilizer. If food waste is to be recycled separately, it needs to be pre-treated, which involves dehydrating it and filtering out food residue. This process generates food wastewater. Food wastewater is a high-concentration organic wastewater with high levels of organic matter, nitrogen, and phosphorus. One ton of this wastewater contains approximately 100 kg of organic matter, 2.5 kg of total nitrogen, and 0.6 kg of total phosphorus. The C, N, and P ratio is moderate. Discharging this high-concentration organic food wastewater without treatment will affect surrounding water bodies and pollute the environment.

[0003] Most existing kitchen wastewater treatment equipment only physically filters out food residues or performs simple treatment through adsorption materials, without addressing the complex components of kitchen wastewater. Kitchen wastewater tends to be acidic and contains high levels of suspended solids and grease. Common methods involve adding flocculants (PAC and PAM) to adjust the pH, but the optimal pH for flocculation and sedimentation is between 6 and 8. Since the original wastewater solution typically has a pH of 3, directly adding PAC and PAM results in rapid hydrolysis of the flocculants, leading to minimal effectiveness.

[0004] Furthermore, existing treatment equipment typically employs dead-end filtration (i.e., full-volume filtration), which traps particles larger than the membrane pores on the filter membrane. This necessitates periodic cleaning or replacement of the filter membrane, which is inconvenient in practical applications. In addition, high-concentration organic kitchen wastewater often undergoes anaerobic digestion. However, anaerobic treatment technology suffers from large land area requirements and high safety risks, making it unsuitable for densely populated and economically developed areas. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a system and method for the non-anaerobic resource utilization of high-concentration organic kitchen wastewater, which can improve the treatment efficiency of kitchen wastewater, while also reducing system operating costs and the system's footprint.

[0006] The technical solution of the present invention is as follows:

[0007] In a first aspect of the invention, a system for the non-anaerobic resource utilization of high-concentration organic kitchen wastewater is provided, comprising a first natural sedimentation tank and a second natural sedimentation tank arranged in parallel. The first natural sedimentation tank is sequentially connected to an equalization tank, a three-phase centrifuge, a first intermediate water tank, a membrane thickening system, and a second intermediate water tank. The second natural sedimentation tank is sequentially connected to a sludge tank, a membrane screen, and a third intermediate water tank. The bottom of the first natural sedimentation tank is connected to the sludge tank, and the top of the second natural sedimentation tank is connected to the equalization tank. The effluent from the third intermediate water tank is connected to the equalization tank.

[0008] In some embodiments of the present invention, the sludge outlet of the membrane grid is sequentially connected to a drying system and an insect breeding system, and the cleaning water outlet of the membrane grid is sequentially connected to a fourth intermediate water tank and a disc separator.

[0009] In some embodiments of the present invention, the outlet of the disc separator is connected to a third intermediate water tank, and the sludge outlet of the disc separator is connected to a drying system.

[0010] In some embodiments of the present invention, the sludge outlet of the three-phase centrifuge is connected to the drying system, and the oil outlet of the three-phase centrifuge is connected to the oil storage tank.

[0011] In some embodiments of the present invention, the effluent from the second intermediate water tank is connected to the MVR system, the biochemical system, and the carbon source system, respectively.

[0012] In some embodiments of the present invention, the hot water generated by the MVR system exchanges heat with the water in the first intermediate water tank, and then enters the cooling system to cool down before entering the biochemical system.

[0013] In some embodiments of the present invention, the organic colloidal slurry outlet of the membrane concentration system is connected to a slurry storage tank, and the outlet of the slurry storage tank is sequentially connected to a fine slag mixing and stirring device and an insect breeding system.

[0014] In a second aspect of the present invention, a process for the non-anaerobic resource utilization of high-concentration organic kitchen wastewater is provided, comprising:

[0015] Kitchen wastewater is pumped into the first natural sedimentation tank and the second natural sedimentation tank respectively. The sludge produced in the first natural sedimentation tank enters the sludge tank for buffering and transition, and then enters the medium membrane screen for filtration. The filtered sludge enters the drying system for drying, so as to realize the resource utilization of sludge.

[0016] The effluent from the top of the second natural sedimentation tank enters the equalization tank for water quality and quantity adjustment, and then enters the three-phase centrifuge for oil and water separation. The oil enters the oil storage tank for storage, and the water enters the first intermediate water tank for buffering treatment before entering the membrane concentration system for concentration and filtration.

[0017] In some embodiments of the present invention, the purified water produced after concentration and filtration by the membrane concentration system is partly pumped into the carbon source system to prepare carbon sources and then sold to wastewater treatment plants; partly pumped directly into the biochemical system, where it is treated by microorganisms and discharged directly into the underground pipe network after meeting the standards; and partly pumped into the MVR system, where the pollutant load in the wastewater is reduced through low-temperature evaporation, and then enters the heat exchange system of the first intermediate water tank to reuse the waste heat before returning to the cooling system for cooling treatment. The cooled water then enters the biochemical system, where it is treated by microorganisms and discharged into the underground pipe network after meeting the standards.

[0018] In some embodiments of the present invention, the odorous gases generated during the entire process are collected under negative pressure, treated by a deodorization system, and then discharged in compliance with emission standards.

[0019] One or more technical solutions of the present invention have the following beneficial effects:

[0020] (1) The present invention adopts two process routes: "natural sedimentation tank" followed by "membrane grid" and "three-phase centrifuge". This allows for the separation of solids and water in kitchen wastewater through physical means without the addition of chemicals. The separated solids can be used for insect breeding and resource utilization because no chemicals are added. At the same time, the separation process does not add chemicals, which greatly reduces the operating cost of pretreatment. The operating cost per ton of water of this process mode is significantly lower than that of chemical treatment.

[0021] (2) The present invention uses a process route mode of “membrane grid” followed by “disc separator + three-phase centrifuge”. The rinsing water of “membrane grid” enters the disc separator for solid-liquid separation. This not only solves the problem that the disc separator is prone to clogging and cannot be used when directly treating kitchen wastewater due to the high solid content, but also solves the problem that the solid-liquid separation effect is poor when the solid particles of kitchen wastewater are directly separated by a three-phase centrifuge due to the small particle size of the solids.

[0022] (3) The present invention sets the “membrane concentration system” after the “natural sedimentation tank + three-phase centrifuge” and the “natural sedimentation tank + membrane grid + disc separator + three-phase centrifuge”. This not only solves the problem that the membrane concentration system is prone to clogging and the high frequency of cleaning makes it impossible to treat kitchen wastewater directly, but also, because the design process makes the solid content of the “membrane concentration system” influent low, it can greatly increase the concentration ratio of the membrane, greatly reduce the generation of concentrate, and reduce operating costs.

[0023] (4) This invention adds a "membrane concentration system" before the "MVR system," which can significantly reduce the solid content of the MVR system influent, with a reduction rate of over 95%. Because the influent water quality of the MVR system is improved, the stability and efficiency of the MVR system are also greatly enhanced, with an efficiency increase of 20%. Simultaneously, due to the presence of the membrane concentration system, part of the effluent can be used as a carbon source for resource utilization, greatly reducing the workload of the MVR system and significantly lowering the operating cost of the "non-anaerobic treatment technology for kitchen wastewater with MVR as the core process," reducing the operating cost per ton of water by 20 yuan.

[0024] (5) The "organic slurry" after membrane concentration of the present invention is mixed with the "fine residue" generated from kitchen waste treatment in a ratio of 1:3, so that the concentrated "organic slurry" can be disposed of in a low-cost manner and subsequently used for insect breeding resource utilization. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the system principle for the non-anaerobic resource utilization of high-concentration organic kitchen wastewater according to the present invention. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] Example 1

[0028] In a typical embodiment of the present invention, a system for the non-anaerobic resource utilization of high-concentration organic kitchen wastewater is proposed, such as... Figure 1 As shown, the system includes a first natural sedimentation tank and a second natural sedimentation tank arranged in parallel. The first natural sedimentation tank is sequentially connected to an equalization tank, a three-phase centrifuge, a first intermediate water tank, a membrane thickening system, a second intermediate water tank, and an MVR system. The second natural sedimentation tank is sequentially connected to a sludge tank, a membrane screen, and a third intermediate water tank. The bottom of the first natural sedimentation tank is connected to the sludge tank, and the top of the second natural sedimentation tank is connected to the equalization tank. The effluent from the third intermediate water tank is connected to the equalization tank.

[0029] By using two natural sedimentation tanks, the continuous treatment of kitchen wastewater can be ensured through their intermittent operation. The sedimentation time for both tanks is set to 24 hours. The kitchen wastewater first enters the natural sedimentation tanks, where solid-liquid separation is achieved through sedimentation. The bottom of the sedimentation tanks contains a mixture of mud and liquid, while the top contains a mixture of oil and water.

[0030] In this embodiment, the first natural sedimentation tank is subsequently connected to a water treatment system, and the second natural sedimentation tank is subsequently connected to a sludge treatment system. The equalization tank in the water treatment system regulates water quality and quantity, and a three-phase centrifuge separates oil and water in the wastewater. The first intermediate water tank serves as a buffer for the next treatment unit, and a membrane thickening system concentrates and filters the water. The second intermediate water tank temporarily stores and distributes clean water. In the sludge treatment system, a membrane screen retains organic sludge in the sludge-water mixture, and the effluent from the membrane screen passes through a third intermediate water tank and enters the equalization tank for subsequent water treatment.

[0031] In this embodiment, the sludge outlet of the membrane grid is sequentially connected to the drying system and the insect breeding system, and the washing water outlet of the membrane grid is sequentially connected to the fourth intermediate water tank and the disc separator. Through the filtration effect of the membrane grid, organic sludge in the sludge-water mixture is retained, and the retained organic sludge has a moisture content of approximately 89%. The organic sludge with a moisture content of 89% is pumped into the drying system at a certain pressure using a screw pump. After evaporation and a moisture content reduction to 80%, it is then conveyed by a screw conveyor and discharged into the insect breeding system for resource utilization.

[0032] Furthermore, the outlet of the disc separator is connected to the third intermediate water tank, and the sludge outlet of the disc separator is connected to the drying system.

[0033] The cleaning water from the membrane screen is pumped into the fourth intermediate water tank at a certain flow rate. After centrifugal separation by a disc separator, the sludge is pumped into the drying system at a certain pressure by a screw pump. The effluent is pumped into the third intermediate water tank at a certain flow rate by a centrifugal pump. After mixing with the effluent from the membrane screen, it is discharged into the equalization tank for further treatment.

[0034] In this embodiment, the sludge outlet of the three-phase centrifuge is connected to the drying system, and the oil outlet of the three-phase centrifuge is connected to the oil storage tank.

[0035] Furthermore, the hot water generated by the MVR system exchanges heat with the water in the first intermediate water tank, and then enters the cooling system to cool down before entering the biochemical system.

[0036] Specifically, the effluent from the second intermediate water tank is connected to the MVR system, the biological system, and the carbon source system, respectively. A portion of the effluent from the second intermediate water tank is pumped into the carbon source system to prepare carbon sources, which are then sold to the wastewater treatment plant. Another portion is directly pumped into the biological system, where it undergoes microbial treatment to meet standards before being discharged directly into the underground pipe network. A third portion is pumped into the MVR system, where low-temperature evaporation significantly reduces the pollutant load in the wastewater. This water is then pumped at a certain flow rate into the equalization tank and the intermediate water tank heat exchange system to reuse the waste heat before returning to the cooling system for further cooling. The cooled water is then pumped at a certain flow rate into the biological system, where it undergoes microbial treatment to meet standards before being discharged into the underground pipe network.

[0037] In this embodiment, the organic colloidal slurry outlet of the membrane concentration system is connected to the slurry storage tank, and the outlet of the slurry storage tank is sequentially connected to the fine slag mixing and stirring equipment and the insect breeding system.

[0038] The organic slurry produced by the membrane concentration system is pumped at a certain flow rate into a slurry storage tank, and then pumped at a certain flow rate into a fine slag mixing and stirring device. After being thoroughly mixed with the fine slag, it is then pumped at a certain flow rate into an insect breeding system for the breeding of black soldier flies.

[0039] The working process for the non-anaerobic resource utilization of high-concentration organic kitchen wastewater provided in this embodiment is as follows:

[0040] Kitchen wastewater is first pumped at a certain flow rate into a first and second natural sedimentation tank. The sedimentation time in both tanks is set for 24 hours. Through this 24-hour natural sedimentation, solid-liquid stratification of the kitchen wastewater is achieved. The bottom of the sedimentation tanks contains a mud mixture, while the top contains an oil-water mixture, with a stratification height ratio of 2:1 between the oil-water mixture and the bottom mud mixture. A decanter is used to send the oil-water mixture from the top of the sedimentation tanks into an equalization tank for water quality and quantity adjustment. The adjusted water is then pumped at a certain flow rate into a three-phase centrifuge. Through centrifugal action, oil and water are separated. The oil is stored in an oil storage tank, while the water enters a first intermediate water tank as a buffer for the next treatment unit. The effluent from intermediate water tank #1 is pumped into the membrane concentration system at a certain flow rate, with a concentration ratio set at 20 times. After membrane concentration and filtration, the resulting clear water is pumped at a certain flow rate, with a portion pumped into intermediate water tank #2, a portion into the carbon source system (for carbon source preparation and sale to wastewater treatment plants), a portion directly into the biological system (for microbial treatment, after meeting standards, directly discharged into the underground pipe network), and a portion into the MVR system (for low-temperature evaporation, significantly reducing the pollutant load in the wastewater). Then, it is pumped at a certain flow rate into the heat exchange system of equalization tank #1 and intermediate water tank to reuse the waste heat before returning to the cooling system for cooling. The cooled water is then pumped at a certain flow rate into the biological system, where it is treated by microorganisms and discharged into the underground pipe network after meeting standards. The organic slurry produced by the 20-fold concentration is pumped at a certain flow rate into the slurry storage tank, and then pumped at a certain flow rate into the fine slag mixing and stirring equipment. The mixing ratio of organic slurry and fine slag is set at 1:3. After being thoroughly mixed with fine residue, the mixture is then pumped into the insect breeding system at a certain flow rate to breed black soldier flies.

[0041] The sludge mixture at the bottom of the natural sedimentation tank is pumped into the sludge tank at a certain flow rate, serving as a transition buffer. The sludge mixture in the sludge tank is then pumped into a membrane grid. Through the filtration effect of the membrane grid, the organic sludge in the sludge water is intercepted, and the moisture content of the intercepted organic sludge is about 89%. The organic sludge with a moisture content of 89% is then pumped into the drying system at a certain pressure using a screw pump. After evaporation and a moisture content reduction to 80%, it is discharged into the insect breeding system via a screw conveyor for resource utilization. The clarified liquid after membrane grid filtration is pumped into the third intermediate water tank at a certain flow rate. The cleaning water for the membrane grid is the effluent from a three-phase centrifuge. This not only reduces water usage costs but also avoids increasing water volume and thus the processing load during operation. The cleaning water for the membrane grid is pumped into the fourth intermediate water tank at a certain flow rate. After centrifugal separation by a disc separator, the sludge is pumped into the drying system at a certain pressure by a screw pump, while the effluent is pumped into the third intermediate water tank at a certain flow rate by a centrifugal pump. After mixing with the effluent from the membrane grid, the mixture is discharged into the equalization tank and then treated as described above. Odors generated by the entire process system are collected under negative pressure and then enter the deodorization system for deodorization treatment. The gas is discharged only after meeting the standards.

[0042] Example 2

[0043] In a typical embodiment of the present invention, a process for the non-anaerobic resource utilization of high-concentration organic kitchen wastewater is proposed, which is implemented using the system of Example 1, including:

[0044] Kitchen wastewater is pumped into the first natural sedimentation tank and the second natural sedimentation tank respectively. The sludge produced in the first natural sedimentation tank enters the sludge tank for buffering and transition, and then enters the medium membrane screen for filtration. The filtered sludge enters the drying system for drying, so as to realize the resource utilization of sludge.

[0045] The effluent from the top of the second natural sedimentation tank enters the equalization tank for water quality and quantity adjustment, and then enters the three-phase centrifuge for oil and water separation. The oil enters the oil storage tank for storage, and the water enters the first intermediate water tank for buffering treatment before entering the membrane concentration system for concentration and filtration.

[0046] Furthermore, the purified water produced after concentration and filtration by the membrane concentration system is partly pumped into the carbon source system to prepare carbon sources for sale to wastewater treatment plants; partly pumped directly into the biological system, where it is treated by microorganisms and discharged directly into the underground pipe network after meeting the standards; and partly pumped into the MVR system, where the pollutant load in the wastewater is reduced through low-temperature evaporation, and then enters the heat exchange system of the first intermediate water tank to reuse the waste heat before returning to the cooling system for cooling treatment. The cooled water then enters the biological system, where it is treated by microorganisms and discharged into the underground pipe network after meeting the standards.

[0047] Furthermore, the odorous gases generated throughout the process are collected under negative pressure and then treated by a deodorization system before being discharged in compliance with emission standards.

[0048] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A system for the non-anaerobic resource utilization of high-concentration organic kitchen wastewater, characterized in that, The system includes a first natural sedimentation tank and a second natural sedimentation tank arranged in parallel. The first natural sedimentation tank is sequentially connected to an equalization tank, a three-phase centrifuge, a first intermediate water tank, a membrane thickening system, and a second intermediate water tank. The second natural sedimentation tank is sequentially connected to a sludge tank, a membrane screen, and a third intermediate water tank. The bottom of the first natural sedimentation tank is connected to the sludge tank, and the top of the second natural sedimentation tank is connected to the equalization tank. The effluent from the third intermediate water tank is connected to the equalization tank. The sludge outlet of the membrane grid is connected in sequence to the drying system and the insect breeding system, and the washing water outlet of the membrane grid is connected in sequence to the fourth intermediate water tank and the disc separator. The effluent from the second intermediate water tank is connected to the MVR system, the biochemical system, and the carbon source system, respectively. The organic colloidal slurry outlet of the membrane concentration system is connected to a slurry storage tank, and the outlet of the slurry storage tank is connected in sequence to a fine slag mixing and stirring device and an insect breeding system.

2. The system for non-anaerobic resource utilization of high-concentration organic kitchen wastewater as described in claim 1, characterized in that, The outlet of the disc separator is connected to the third intermediate water tank, and the sludge outlet of the disc separator is connected to the drying system.

3. The system for non-anaerobic resource utilization of high-concentration organic kitchen wastewater as described in claim 1, characterized in that, The sludge outlet of the three-phase centrifuge is connected to the drying system, and the oil outlet of the three-phase centrifuge is connected to the oil storage tank.

4. The system for non-anaerobic resource utilization of high-concentration organic kitchen wastewater as described in claim 1, characterized in that, The hot water generated by the MVR system exchanges heat with the water in the first intermediate water tank, and then enters the cooling system to cool down before entering the biochemical system.

5. A process for the non-anaerobic resource utilization of high-concentration organic kitchen wastewater, implemented using the system for the non-anaerobic resource utilization of high-concentration organic kitchen wastewater as described in any one of claims 1-4, characterized in that, include: High-concentration organic kitchen wastewater is pumped into the first natural sedimentation tank and the second natural sedimentation tank, respectively; The sludge produced from the first and second natural sedimentation tanks enters the sludge tank for buffering and transition, and then enters the membrane grid for filtration. The filtered sludge enters the drying system for drying, realizing the resource utilization of sludge. The top effluent from the first and second natural sedimentation tanks enters the equalization tank for water quality and quantity adjustment, and then enters the three-phase centrifuge for oil and water separation. The oil enters the oil storage tank for storage, and the water enters the first intermediate water tank for buffering treatment before entering the membrane concentration system for concentration and filtration.

6. The process for non-anaerobic resource utilization of high-concentration organic kitchen wastewater as described in claim 5, characterized in that, The purified water produced after concentration and filtration by the membrane concentration system is divided into three parts: part is pumped into the carbon source system to prepare carbon sources for sale to wastewater treatment plants; part is directly pumped into the biological system, where it is treated by microorganisms and discharged directly into the underground pipe network after meeting the standards; and part is pumped into the MVR system, where the pollutant load in the wastewater is reduced through low-temperature evaporation, and then it enters the heat exchange system of the first intermediate water tank to reuse the waste heat before returning to the cooling system for cooling treatment. The cooled water then enters the biological system, where it is treated by microorganisms and discharged into the underground pipe network after meeting the standards.

7. The process for non-anaerobic resource utilization of high-concentration organic kitchen wastewater as described in claim 5, characterized in that, The odor generated during the entire process is collected under negative pressure, treated by a deodorization system, and then discharged in compliance with emission standards.

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