Bypass type two-phase anaerobic process and system for kitchen waste treatment and kitchen waste treatment plant comprising system

Abstract

The invention discloses a bypass type two-phase anaerobic process and system for kitchen waste treatment and a kitchen waste treatment plant comprising the system, and relates to the technical field of kitchen waste treatment.The bypass type two-phase anaerobic process comprises the following steps that organic slurry obtained through kitchen waste pretreatment is fed into an adjusting tank to be stored; the organic slurry is fed into a hydrolytic acidification tank, macromolecular organic matters in the organic slurry are converted into micromolecular matters by hydrolytic bacteria in the hydrolytic acidification tank, and the micromolecular matters are converted into organic acid, hydrogen and carbon dioxide by acidizing bacteria; the organic slurry subjected to hydrolytic acidification is fed into an anaerobic reaction tank, and organic acid in the organic slurry is converted into methane through methanogens in the anaerobic reaction tank; when the pH in the anaerobic reaction tank is 1t; 6.5 or VFAgt, or VFAgt; when the concentration is 3000 mg / L, the organic slurry subjected to hydrolytic acidification flows back to the regulating tank. According to the invention, the amount of slurry entering the anaerobic reaction tank can be flexibly controlled, the feeding load is balanced, and the load impact of the anaerobic reaction tank is effectively buffered, so that the retention time of the anaerobic reactor can be prolonged.

Description

Technical Field

[0001] This invention relates to the field of food waste treatment technology, and more specifically, to a bypass-type two-phase anaerobic process and system for food waste treatment, as well as a food waste treatment plant including the system, which is particularly suitable for food waste treatment plants with large regional seasonal differences in collection volume and composition. Background Technology

[0002] Currently, my country's food waste treatment industry generally adopts the "pretreatment + anaerobic digestion" process, with the anaerobic digestion system being the core component, directly affecting the organic matter degradation efficiency, biogas production, and system stability. Given the complex composition of food waste (high oil, high salt, high solids content) and the large fluctuations in water quality (organic matter concentration varies by 30%-50%), a two-phase anaerobic system has become the mainstream technology choice. This system divides the anaerobic digestion process into two independently operating phases: the "acid-producing phase" (hydrolysis acidification tank 6) and the "methan-producing phase" (anaerobic reactor). By separating these different reaction stages, precise control of the microbial community is achieved.

[0003] The acidifying bacteria in hydrolysis acidification tank 6 can adapt to a wide range of pH (5.0-8.0) and temperature (30-60℃), rapidly decomposing macromolecular organic matter (carbohydrates, proteins, fats) into intermediate products such as volatile fatty acids (VFAs) and alcohols. In contrast, the methanogenic bacteria in the anaerobic reactor are extremely sensitive to the environment, requiring strict control of pH (6.8-7.2), VFA concentration (<3000 mg / L), and toxic substances (such as ammonia nitrogen <1500 mg / L). They can only utilize simple substrates (organic acids, hydrogen / carbon dioxide) to generate methane. This two-phase separation avoids the inhibition of methanogenic bacteria by the acidic environment during the acidification stage, allowing both types of microorganisms to grow under optimal conditions and significantly improving the system's operational stability.

[0004] Meanwhile, the acid-producing phase can withstand high load shocks (volume load can reach 10-15 kg COD / (m³・d)), rapidly degrade particulate organic matter, and reduce the treatment pressure of the subsequent methanogenic phase; the methanogenic phase, by controlling the hydraulic retention time (HRT=20-30 days) and sludge retention time (SRT=30-60 days), enriches highly active methanogenic bacteria, increasing the organic matter degradation rate from 70%-75% in the single-phase system to 80%-85%, and increasing biogas production by 15%-20%.

[0005] In response to the typical characteristics of food waste, such as "concentrated feeding during lunch and evening peak hours and sudden changes in composition on weekends and holidays", the acid-producing phase can serve as a "buffer unit" to temporarily store incompletely hydrolyzed materials, preventing the methanogenic phase from acidifying and collapsing due to a sudden increase in load. The segmented control advantage of the two-phase system is even more significant, especially in the case of high temperatures in summer (which easily leads to material spoilage and acidification) or low temperatures in winter (which reduces microbial activity).

[0006] Although two-phase anaerobic systems have become the industry standard, traditional two-phase anaerobic systems have revealed the following key problems in actual operation: 1. Significant Risk of Load Imbalance: The VFA concentration in the acidogenic phase effluent is significantly affected by feed fluctuations (normal range 2000-4000 mg / L, extreme conditions can reach over 6000 mg / L). If all of it is directly fed into the methanogenic phase, it can easily lead to excessive VFA concentration in the latter, triggering "acidification inhibition." The pH of the methanogenic phase can drop sharply from 7.0 to 6.0 within a few days, resulting in a significant decrease in biogas production. Not only does it take nearly half a month to restore the system, but sodium bicarbonate also needs to be added during this period to maintain normal alkalinity.

[0007] 2. Hydraulic Retention Time (HRT) Matching Failure: The solids content (TS: 8%-14%) of the slurry after pretreatment of kitchen waste fluctuates frequently. When the solids content increases, the hydrolysis rate of the acid-producing phase slows down, and the HRT needs to be extended to ensure the hydrolysis effect. However, if the methanogenic phase is still fed at a fixed flow rate, it will lead to a shortening of its HRT, increased sludge loss, and a decrease in the concentration of methanogenic bacteria. As a result, under high solids content conditions without a bypass, the concentration of methanogenic sludge will decrease, and the organic matter removal rate will decrease.

[0008] 3. Lack of emergency response capabilities: When equipment failure occurs in the methanogenic phase (such as stirrer failure or heating device failure), if there is no bypass, the entire system can only be forced to shut down, and the system restart will take more than half a month.

[0009] In summary, although existing two-phase anaerobic systems have achieved microbial function optimization through stage separation, their efficient operation depends on the dynamic balance between the acid-producing phase and the methanogenic phase. However, due to the lack of a regulating bypass, they have significant deficiencies in terms of load adaptability, emergency response mechanisms, and operational economy, thus affecting the stable operation and efficiency improvement of food waste treatment plants. Summary of the Invention

[0010] The purpose of this invention is to provide a bypass-type two-phase anaerobic process, system, and food waste treatment plant including the system for food waste treatment. This invention can flexibly control the amount of slurry entering the anaerobic reactor, balance the feed load, and effectively buffer the load impact of the anaerobic reactor, thereby extending the residence time of the anaerobic reactor, improving the organic matter degradation efficiency, and enhancing the reaction efficiency of the anaerobic system in the food waste treatment plant. It also improves the system's tolerance to load fluctuations and operational stability, not only avoiding economic losses caused by system instability but also increasing the yield of biogas, an economically valuable byproduct of anaerobic fermentation, thereby improving the economic benefits of the food waste treatment plant.

[0011] To achieve the objective of this invention, the technical solution adopted is: a bypass-type two-phase anaerobic process for treating kitchen waste, comprising the following steps: Step 1: The organic slurry obtained from the pretreatment of kitchen waste is sent to the equalization tank for storage; Step 2: Send the organic slurry in the equalization tank into the hydrolysis acidification tank. The hydrolysis bacteria in the hydrolysis acidification tank will convert the large organic molecules in the organic slurry into small molecules, and the acidification bacteria will convert the small molecules into organic acids, hydrogen and carbon dioxide. Step 3: The organic slurry treated in Step 2 is sent into an anaerobic reactor. Methanogenic bacteria in the anaerobic reactor convert the organic acids in the wastewater into methane. When the pH in the anaerobic reactor is <6.5 or VFA is >3000mg / L, the organic slurry treated in Step 2 is returned to the equalization tank.

[0012] Furthermore, the steps for pre-treating kitchen waste in step 1 are as follows: Step 11: Sorting and crushing the kitchen waste to be processed to obtain slurry; Step 12: Remove sand and impurities from the slurry in Step 11 to obtain an oil-water mixture; Step 13: Centrifuge the oil-water mixture from Step 12 to extract the oil, obtaining an organic slurry.

[0013] Furthermore, in step 2, the organic slurry remains in the hydrolysis acidification tank for 4 to 5 days.

[0014] Furthermore, in step 3, the organic slurry remains in the anaerobic reactor for 30 to 35 days.

[0015] Furthermore, the wastewater treated in step 3 is sent to a centrifugal dewatering machine for centrifugal dewatering and solid-liquid separation. The resulting liquid is biogas slurry, which is then sent to the wastewater treatment system for purification.

[0016] The bypass-type two-phase anaerobic system based on the above-mentioned bypass-type two-phase anaerobic process for food waste treatment includes an equalization tank, a hydrolysis acidification tank, and an anaerobic reaction tank connected in sequence by connecting pipelines, and a three-way valve is installed on the connecting pipeline connecting the hydrolysis acidification tank and the anaerobic reaction tank; it also includes an emergency tank, the second outlet of the three-way valve is connected to the emergency tank through a return pipeline, and the emergency tank and the equalization tank are connected by a channel, in which a switch valve is installed.

[0017] Furthermore, the emergency pool and the regulating pool are an integrated structure, and the emergency pool and the regulating pool are separated by a partition wall, with the connecting passage located on the partition wall.

[0018] Furthermore, the effective reaction volume of the anaerobic reactor is 6-8 times the effective reaction volume of the hydrolysis acidification reactor.

[0019] Furthermore, the hydrolysis acidification tank and the anaerobic reaction tank are cylindrical sealed tanks.

[0020] Furthermore, the hydrolysis acidification tank and the anaerobic reaction tank are equipped with a stirrer.

[0021] Furthermore, a reflux pump, regulating valve, and flow meter are also installed on the reflux pipeline.

[0022] A food waste treatment plant includes a bypass-type two-phase anaerobic system for food waste treatment as described above, and further includes a sorting, crushing and pulping integrated machine, a sand and impurity removal machine, and a centrifugal oil extraction device connected in sequence, with the wastewater outlet of the centrifugal oil extraction device connected to a regulating tank.

[0023] Furthermore, it also includes a centrifugal dewatering machine connected to the outlet of the anaerobic reactor, and the liquid outlet of the centrifugal dewatering machine is connected to the wastewater treatment system.

[0024] Furthermore, the gas outlet of the anaerobic reactor is connected to the air inlet of the biogas purification unit, and the outlet of the biogas purification unit is connected to a biogas generator.

[0025] The beneficial effects of this invention are: 1. Since the main function of the hydrolysis acidification tank is to decompose complex organic matter into volatile fatty acids (VFA), and the anaerobic reactor needs to operate under strict pH and VFA concentration conditions, if the hydrolysis acidification tank produces acid too quickly or accumulates too much VFA, it may affect the activity of methanogenic bacteria in the anaerobic reactor. In this invention, when the pH in the anaerobic reactor is <6.5 or VFA >3000 mg / L, the organic slurry treated by the hydrolysis acidification tank is returned to the equalization tank. This allows for flexible control of the amount of slurry entering the anaerobic reactor, balancing the feed load and avoiding load shocks to the anaerobic reactor. At the same time, due to the large differences in regional seasonal collection volume and composition, the composition and concentration of food waste feed fluctuate greatly. In this invention, the organic slurry treated by the hydrolysis acidification tank can also be directly sent back to the emergency tank during feed fluctuations to buffer the impact load on the anaerobic reactor and maintain system stability.

[0026] 2. By recirculating the organic slurry treated in the hydrolysis acidification tank back into the equalization tank, this invention allows for adjustment of the hydraulic retention time (HRT) of the subsequent anaerobic treatment system according to the feed load, thus matching the HRT of the hydrolysis acidification tank and the anaerobic reactor. When the solids content of the slurry increases, the feed load increases, and it is necessary to extend the hydraulic retention time of the anaerobic reactor, the organic slurry treated in the hydrolysis acidification tank can be recirculated back into the equalization tank. This not only buffers the load impact on the anaerobic reactor but also extends the residence time of the anaerobic reactor, thereby improving the organic matter degradation efficiency.

[0027] 3. When the anaerobic reactor is being commissioned or restarted, the feed rate into the hydrolysis acidification tank is controlled by returning the organic slurry treated in the hydrolysis acidification tank to the equalization tank, thereby gradually increasing the load and ensuring the adaptability of the microbial community in the hydrolysis acidification tank and the anaerobic reactor.

[0028] 4. By returning the organic slurry treated in the hydrolysis acidification tank to the equalization tank, the reaction efficiency and stability of the anaerobic system in the food waste treatment plant are improved. This not only avoids economic losses caused by system instability, but also increases the yield of biogas, an economically valuable byproduct of anaerobic fermentation, thereby improving the economic benefits of the food waste treatment plant. Attached Figure Description

[0029] The accompanying drawings illustrate exemplary embodiments of the invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification.

[0030] Figure 1 This is a system diagram of the bypass-type two-phase anaerobic system for food waste treatment provided by the present invention; Figure 2 This is a system diagram of a food waste treatment plant provided by the present invention.

[0031] The attached diagram shows the markings and corresponding component names: 1. Sorting, crushing and pulping integrated machine; 2. Sand and impurity removal machine; 3. Centrifugal oil extraction equipment; 4. Equalization tank; 5. Emergency tank; 6. Hydrolysis acidification tank; 7. Anaerobic reactor; 8. Centrifugal dewatering machine; 9. Wastewater treatment system; 10. Three-way valve; 11. Return pipeline; 12. Partition wall; 13. Switch valve; 14. Biogas purification unit; 15. Biogas generator. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0034] This invention provides a bypass-type two-phase anaerobic process for treating food waste, comprising the following steps: Step 1: The kitchen waste to be processed is crushed and sorted. The sorted solid slag is sent to a subsequent solid slag storage tank for outsourced disposal, while the sorted slurry is treated to remove sand and impurities. The solid slag obtained from the sand and impurities removal treatment is sent to a subsequent solid slag storage tank for outsourced disposal. The oil-water mixture obtained from the sand and impurities removal treatment is centrifuged to extract oil. The oil obtained from the centrifuged oil extraction is sent to a subsequent oil storage tank for storage and sale. The organic slurry obtained from the centrifuged oil extraction is sent to the equalization tank 4 for storage.

[0035] Step 2: The organic slurry in the equalization tank 4 is sent to the hydrolysis acidification tank 6. The hydrolysis bacteria in the hydrolysis acidification tank 6 first break down and decompose the large organic molecules in the organic slurry into water-soluble small molecules. For example, proteins are hydrolyzed into amino acids, polysaccharides into monosaccharides or disaccharides, and fats into glycerol and fatty acids. Then, the acidifying bacteria convert the small molecules in the organic slurry into organic acids, CO2, and H2. The reaction temperature in the hydrolysis acidification tank 6 is 30-38°C, the pH value in the hydrolysis acidification tank 6 is 5.5-6.5, and the organic slurry stays in the hydrolysis acidification tank 6 for 4-5 days. Step 3: The organic slurry treated in Step 2 is fed into anaerobic reactor 7. Methanogenic bacteria in anaerobic reactor 7 convert the organic acids in the organic slurry into methane. The reaction temperature in anaerobic reactor 7 is 30-38°C, the pH value in anaerobic reactor 7 is 6.8-7.5, and the residence time of the organic slurry in anaerobic reactor 7 is 30-35 days. During the process of feeding the organic slurry treated in Step 2 into anaerobic reactor 7, if the pH in anaerobic reactor 7 is <6.5 or VFA >3000mg / L, the organic slurry treated in Step 2 is returned to equalization tank 4.

[0036] Step 4: The organic slurry processed in Step 3 is sent to centrifugal dewatering machine 8 for centrifugal dewatering to separate solid and liquid into biogas residue and biogas slurry. The biogas residue is sent to the subsequent biogas residue storage tank for outsourced disposal, and the waste liquid obtained from the biogas slurry is sent to the subsequent wastewater treatment system 9 for purification treatment.

[0037] In this invention, when an emergency tank 5 is present and the pH in the anaerobic reactor 7 is <6.5 or VFA is >3000mg / L, the organic slurry treated in step 2 is returned to the emergency tank 5. When the hydrolysis acidification tank 6 and the anaerobic reactor 7 are operating normally, the organic slurry sent into the emergency tank 5 is then sent into the regulating tank 4 for use.

[0038] Based on the above-mentioned bypass-type two-phase anaerobic process for food waste treatment, such as Figure 1As shown, the present invention also provides a bypass-type two-phase anaerobic system for food waste treatment, including an equalization tank 4, a hydrolysis acidification tank 6, and an anaerobic reaction tank 7 connected in sequence by connecting pipelines. The equalization tank 4 is used to store the organic slurry to be treated, the hydrolysis acidification tank 6 is used to perform hydrolysis acidification treatment on the organic slurry, and the anaerobic reaction tank 7 is used to produce methane from the hydrolyzed and acidified organic slurry after anaerobic reaction. A three-way valve 10 is installed on the connecting pipe for connecting the hydrolysis acidification tank 6 and the anaerobic reactor 7. The inlet of the three-way valve 10 is connected to the hydrolysis acidification tank 6 through the connecting pipe, and the first outlet of the three-way valve 10 is connected to the anaerobic reactor 7 through the connecting pipe. At the same time, the bypass type two-phase anaerobic system provided by the present invention also includes an emergency pool 5. The second outlet of the three-way valve 10 is connected to the emergency pool 5 through a return pipe 11, and the emergency pool 5 is connected to the regulating pool 4 through a channel. A switch valve 13 is installed in the channel. The switch valve 13 is normally closed. The connection or disconnection of the channel is controlled by controlling the switch valve 13.

[0039] In this invention, the emergency tank 5 and the equalization tank 4 can both be located underground, while the hydrolysis acidification tank 6 and the anaerobic reactor 7 are located above ground. The emergency tank 5 is only used to store the organic slurry delivered from the hydrolysis acidification tank 6 in emergency situations, and is not intended for long-term use. Specifically, it is used when the feed load of the anaerobic reactor 7 needs to be appropriately reduced due to the need for stable operating conditions; or when the solids content of the organic slurry delivered from the hydrolysis acidification tank 6 increases, and the feed load of the anaerobic reactor 7 increases, thus requiring an extension of the hydraulic retention time of the anaerobic reactor. That is, in this invention, the activation of the emergency tank 5 and the return pipeline 11 is only an emergency adjustment measure for rare extreme operating conditions in the anaerobic reactor 7, thereby preventing the collapse of the anaerobic reactor 7. Although this emergency adjustment measure has a low probability of being activated, if the anaerobic reactor 7 encounters extreme operating conditions and there is no such adjustment measure, the entire anaerobic reactor 7 will collapse. At the same time, the anaerobic reactor 7 is the core processing unit of the entire food waste treatment plant. The collapse of the anaerobic reactor 7 is equivalent to the shutdown of the entire food waste treatment plant. The emergency adjustment measure of setting up the return pipeline 11 in this invention plays a significant role in the entire food waste treatment plant under extreme operating conditions of the anaerobic reactor 7.

[0040] In this invention, the emergency pool 5 and the regulating pool 4 are an integrated structure. Specifically, a large concrete pool is constructed underground, and a partition wall 12 is installed within this concrete pool, dividing the interior into two chambers, thus forming the emergency pool 5 and the regulating pool 4. At this point, the regulating pool 4 and the emergency pool 5 are adjacent to each other but not connected. During construction, the sizes of the emergency pool 5 and the regulating pool 4 should meet the requirement that the organic slurry entering the anaerobic reactor 7 of the food waste treatment plant can be temporarily stored for 12 hours. When the emergency pool 5 and the regulating pool 4 are separated only by a partition wall 12, the passageway is constructed on the partition wall 12.

[0041] In this invention, since the hydraulic residence time of the hydrolysis acidification tank 6 is designed to be 4 to 5 days and the hydraulic residence time of the anaerobic reactor 7 is designed to be 30 to 35 days, when selecting the anaerobic reactor 7 and the hydrolysis acidification tank 6, the effective reaction volume of the anaerobic reactor 7 and the effective reaction volume of the hydrolysis acidification tank 6 are 6 to 8:1; at the same time, the hydrolysis acidification tank 6 and the anaerobic reactor 7 are cylindrical sealed tanks.

[0042] In this invention, the hydrolysis acidification tank 6 and the anaerobic reaction tank 7 are equipped with stirrers. The stirrer in the hydrolysis acidification tank 6 can make the organic slurry fully mixed with the hydrolytic bacteria and acidifying bacteria after entering the hydrolysis acidification tank 6. The stirrer in the anaerobic reaction tank 7 can make the organic slurry fully mixed with the methanogenic bacteria after entering the anaerobic reaction tank 7, which is beneficial to promoting the degradation reaction efficiency of the microbial community.

[0043] In this invention, in order to facilitate the control of the amount of fluid returned to the emergency pool 5, a return pump, a regulating valve and a flow meter are also installed on the return pipeline 11. The regulating valve is an electric butterfly valve, which can accurately control the flow rate of the return pipeline 11. When the online monitoring instrument of the anaerobic reactor 7 displays pH < 6.5 or VFA > 3000 mg / L, the electric butterfly valve on the return pipeline 11 can be opened to introduce the slurry from the hydrolysis acidification tank 6 into the emergency pool 5.

[0044] In this invention, an emergency pool 5 is set up, and the emergency pool 5 is connected to the outlet end of the hydrolysis acidification tank 6 through the return pipe 11 and the three-way valve 10. When the anaerobic reactor 7 needs to appropriately reduce the feed load due to the need for stable operation, part of the organic slurry treated by the hydrolysis acidification tank 6 can be sent into the emergency pool 5 through the return pipe 11. This can not only buffer the load impact of the anaerobic reactor 7, but also extend the residence time of the anaerobic reactor and improve the degradation efficiency of organic matter. When the operating conditions of the anaerobic reactor 7 gradually stabilize and the normal feed is restored, the switch valve 13 in the channel can be opened, so that the organic slurry temporarily stored in the emergency pool 5 will enter the hydrolysis acidification tank 6 for treatment.

[0045] Based on the above-mentioned bypass-type two-phase anaerobic system for food waste treatment, such as Figure 2 As shown, the present invention also provides a food waste treatment plant, including the bypass-type two-phase anaerobic system for food waste treatment as described above, and further including a sorting, crushing and pulping integrated machine 1, a sand and impurity removal machine 2, and a centrifugal oil extraction device 3 connected in sequence; the sorting, crushing and pulping integrated machine 1 is used to sort and crush the solid-liquid mixture of food waste to prepare a slurry; the sand and impurity removal machine 2 is used to remove sand and impurities from the slurry processed by the sorting, crushing and pulping integrated machine 1 to obtain an oil-water mixture; the centrifugal oil extraction device 3 is used to separate the oil-water mixture to obtain an organic slurry after oil extraction.

[0046] In this invention, the organic slurry outlet of the centrifugal oil extraction device 3 is connected to the equalization tank 4, thereby sending the pretreated organic slurry into the hydrolysis and acidification tank 6 for hydrolysis and acidification treatment. In this invention, the solid slag discharged from the sorting, crushing, and pulping integrated machine 1 and the sand and impurity removal machine 2 can be transported by elevator to a subsequent solid slag storage tank for outsourced disposal, while the oil outlet of the centrifugal oil extraction device 3 can be transported through pipelines to a subsequent oil storage tank for storage and sale.

[0047] In this invention, to facilitate the treatment of wastewater after anaerobic treatment, the outlet of the anaerobic reactor 7 is also connected to a centrifugal dewatering machine 8. The centrifugal dewatering machine 8 can centrifuge and dewater the wastewater after anaerobic treatment to separate solid and liquid components. The separated biogas residue can be sent out through the solid residue outlet of the centrifugal dewatering machine 8 and transported to the subsequent biogas residue storage tank for outsourced disposal. The liquid outlet of the centrifugal dewatering machine 8 can be connected to the wastewater treatment system 9 through a pipeline, so that the biogas liquid separated by the centrifugal dewatering machine 8 can be sent into the wastewater treatment system 9 for purification treatment.

[0048] In this invention, the gas outlet of the anaerobic reactor 7 is connected to the air inlet of the biogas purification unit 14, and the outlet of the biogas purification unit 14 is connected to the inlet of the biogas generator 15, so that the biogas generated by the anaerobic reaction is purified by the biogas purification unit 14 and then sent into the biogas generator 15 for power generation.

[0049] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A bypass-type two-phase anaerobic process for treating kitchen waste, characterized in that, Includes the following steps: Step 1: The organic slurry obtained from the pretreatment of kitchen waste is sent to the equalization tank (4) for storage; Step 2: Send the organic slurry in the equalization tank (4) into the hydrolysis acidification tank (6). The hydrolysis bacteria in the hydrolysis acidification tank (6) convert the large molecular organic matter in the organic slurry into small molecular matter, and the acidification bacteria convert the small molecular matter into organic acid, hydrogen and carbon dioxide. Step 3: The organic slurry treated in step 2 is sent into the anaerobic reactor (7). Methanogenic bacteria in the anaerobic reactor (7) convert the organic acids in the organic slurry into methane. When the pH in the anaerobic reactor (7) is <6.5 or VFA is >3000mg / L, the organic slurry treated in step 2 is returned to the equalization tank (4).

2. The bypass-type two-phase anaerobic process for treating kitchen waste according to claim 1, characterized in that, The steps for pre-treatment of kitchen waste in step 1 are as follows: Step 11: Sorting and crushing the kitchen waste to be processed to obtain slurry; Step 12: Remove sand and impurities from the slurry in Step 11 to obtain an oil-water mixture; Step 13: Centrifuge the oil-water mixture from Step 12 to extract the oil, resulting in an organic slurry after oil extraction.

3. The bypass-type two-phase anaerobic process for treating kitchen waste according to claim 1, characterized in that, In step 2, the organic slurry stays in the hydrolysis acidification tank (6) for 4 to 5 days.

4. The bypass-type two-phase anaerobic process for food waste treatment according to claim 1, characterized in that, In step 3, the wastewater stays in the anaerobic reactor (7) for 30 to 35 days.

5. The bypass-type two-phase anaerobic process for treating kitchen waste according to claim 1, characterized in that, The wastewater treated in step 3 is sent to a centrifugal dewatering machine (8) for centrifugal dewatering and solid-liquid separation. The resulting liquid is biogas slurry, which is then sent to a wastewater treatment system (9) for purification.

6. A system based on any one of claims 1 to 5 for the bypass-type two-phase anaerobic process for food waste treatment, characterized in that, It includes a regulating tank (4), a hydrolysis acidification tank (6) and an anaerobic reaction tank (7) connected in sequence by connecting pipes, and a three-way valve (10) is installed on the connecting pipe connecting the hydrolysis acidification tank (6) and the anaerobic reaction tank (7); it also includes an emergency tank (5), the second outlet of the three-way valve (10) is connected to the emergency tank (5) through a return pipe (11), and the emergency tank (5) and the regulating tank (4) are connected by a channel, in which a switch valve (13) is installed.

7. The bypass-type two-phase anaerobic system for food waste treatment according to claim 6, characterized in that, The emergency pool (5) and the regulating pool (4) are an integral structure, and the emergency pool (5) and the regulating pool (4) are separated by a partition wall (12), with the connecting channel located on the partition wall (12).

8. The bypass-type two-phase anaerobic system for food waste treatment according to claim 6, characterized in that, The effective reaction volume of the anaerobic reactor (7) is 6-8 times the effective reaction volume of the hydrolysis acidification reactor (6).

9. A food waste treatment plant, comprising a bypass-type two-phase anaerobic system for food waste treatment as described in claim 6, 7 or 8, and further comprising a sorting, crushing and pulping integrated machine (1), a sand and impurity removal machine (2), and a centrifugal oil extraction device (3) connected in sequence, wherein the organic slurry outlet of the centrifugal oil extraction device (3) is connected to a regulating tank (4).

10. The food waste treatment plant according to claim 9, characterized in that, It also includes a centrifugal dehydrator (8) connected to the outlet of the anaerobic reactor (7), and the liquid outlet of the centrifugal dehydrator (8) is connected to the wastewater treatment system (9); the gas outlet of the anaerobic reactor (7) is connected to the air inlet of the biogas purification unit (14), and the outlet end of the biogas purification unit (14) is connected to a biogas generator (15).

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