Low-carbon multistage membrane distillation bioreactor for treating landfill leachate

Abstract

The invention discloses a low-carbon multi-stage membrane distillation bioreactor for treating landfill leachate, and belongs to the field of landfill leachate treatment.The low-carbon multi-stage membrane distillation bioreactor comprises a membrane treatment unit, a temperature control unit, a condensation cooling unit and a pipeline pump valve unit, the landfill leachate is pumped into a membrane pool, and the temperature of the membrane pool is kept constant through the temperature control unit; steam generated by the steam pressure difference on the two sides of the hydrophobic membrane penetrates through the membrane holes and then is condensed into produced water, so that the membrane separation process is realized, and free and flexible combination of serial and parallel operation conditions of the multi-stage membrane distillation bioreactor can be realized by switching the pipeline pump valves, so that the purpose of further improving the effluent quality is achieved. The system can overcome the defects of membrane pollution, low treatment efficiency, unstable water quality of produced water and large heat energy consumption caused by salt accumulation in a single membrane distillation technology, and has the advantages of high treatment efficiency, good water quality of discharged water, self-supply of energy, high methane recovery rate, capability of controlling the temperature of the reactor as required, and multi-stage free and flexible switching combination.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of landfill leachate treatment, in particular to a low-carbon multi-stage membrane distillation bioreactor for treating landfill leachate. BACKGROUND

[0002] Landfill leachate in a landfill treatment plant is high-concentration organic wastewater generated by the fermentation decomposition of water contained in the landfill itself, external water and organic matter during the landfill, landfill or incineration process. The composition is extremely complex and the pollutant content is extremely high, making it very difficult to treat. Once the landfill leachate seeps into groundwater or surface water, it will cause serious pollution to the water body, greatly affecting the aquatic ecosystem and water quality safety.

[0003] At present, the traditional landfill leachate treatment system mostly adopts the "biological treatment + RO reverse osmosis" process, but the biological treatment link usually has low denitrification efficiency, large sludge yield and needs additional carbon source. The reverse osmosis membrane (RO) has problems such as salt internal circulation, frequent membrane blockage and high energy consumption. In recent years, membrane distillation (MD) technology has gradually become a research hotspot. Although it has strong separation ability, single membrane distillation technology also has problems such as membrane pollution caused by salt accumulation, low treatment efficiency, unstable water quality, high heat energy consumption and the like when treating high-concentration organic wastewater such as landfill leachate. SUMMARY

[0004] The purpose of the present application is to provide a low-carbon multi-stage membrane distillation bioreactor for treating landfill leachate, which overcomes the shortcomings of single membrane distillation technology such as membrane pollution caused by salt accumulation, low treatment efficiency, unstable water quality and high heat energy consumption, and has the advantages of high treatment efficiency, good effluent water quality, energy self-sufficiency, high methane recovery rate, reactor temperature control according to needs, and multi-stage free flexible switching combination.

[0005] To achieve the above-mentioned purpose, the present application provides a low-carbon multi-stage membrane distillation bioreactor for treating landfill leachate, comprising: A membrane treatment unit pumps the landfill leachate into a membrane pool, and realizes membrane separation by condensing the steam passing through the membrane pores into product water through the vapor pressure difference on both sides of the hydrophobic membrane. A temperature control unit keeps the membrane treatment unit at a constant temperature. A condensation and cooling unit condenses the steam passing through the membrane pores into product water. A pipeline pump valve unit realizes the combination of series and parallel operation conditions of the multi-stage membrane distillation bioreactor through the switching of the pipeline pump valve.

[0006] Preferably, the membrane treatment unit comprises a membrane distillation assembly one, a membrane pool one, a constant temperature water tank one, a membrane distillation assembly two, a membrane pool two, a constant temperature water tank two, a membrane distillation assembly three, a membrane pool three and a constant temperature water tank three. Membrane cell one, membrane cell two and membrane cell three are respectively provided with membrane distillation assembly one, membrane distillation assembly two and membrane distillation assembly three, and the outer parts of the membrane cell one, the membrane cell two and the membrane cell three are constant-temperature water tank one, constant-temperature water tank two and constant-temperature water tank three, which provide constant-temperature conditions for the membrane cell one, the membrane cell two and the membrane cell three. The membrane cell one, the membrane cell two and the membrane cell three are connected with the membrane cell one exhaust pipe, the membrane cell two exhaust pipe and the membrane cell three exhaust pipe, and the membrane cell one exhaust pipe, the membrane cell two exhaust pipe and the membrane cell three exhaust pipe are connected with the same pipeline and connected to the gas storage tank.

[0007] Preferably, the membranes of the membrane distillation assembly one, the membrane distillation assembly two and the membrane distillation assembly three are all immersed hydrophobic microporous membranes, the material is polytetrafluoroethylene PTFE, the pore size is 0.2 μm, and the water contact angle is > 120°.

[0008] Preferably, the temperature control unit comprises a steam heat exchanger, a constant-temperature water tank one water inlet pipe, a constant-temperature water tank one water outlet pipe, a constant-temperature water tank two water inlet pipe, a constant-temperature water tank two water outlet pipe, a constant-temperature water tank three water inlet pipe, a constant-temperature water tank three water outlet pipe and a constant-temperature water tank backflow water pump. The constant-temperature water tank one, the constant-temperature water tank two and the constant-temperature water tank three are respectively connected with the constant-temperature water tank one water inlet pipe, the constant-temperature water tank two water inlet pipe and the constant-temperature water tank three water inlet pipe, the constant-temperature water tank one water inlet pipe, the constant-temperature water tank two water inlet pipe and the constant-temperature water tank three water inlet pipe are connected with the same pipeline and connected to the steam heat exchanger, the constant-temperature water tank one, the constant-temperature water tank two and the constant-temperature water tank three are respectively connected with the constant-temperature water tank one water outlet pipe, the constant-temperature water tank two water outlet pipe and the constant-temperature water tank three water outlet pipe, the constant-temperature water tank one water outlet pipe, the constant-temperature water tank two water outlet pipe and the constant-temperature water tank three water outlet pipe are connected with the same pipeline and connected to the constant-temperature water tank backflow water pump, and the constant-temperature water tank backflow water pump is connected with the steam heat exchanger.

[0009] Preferably, the condensation and cooling unit comprises a membrane cell one condenser, a membrane cell one pressure water tank and a membrane cell one suction pump connected in sequence, a membrane cell two condenser, a membrane cell two pressure water tank and a membrane cell two suction pump connected in sequence, a membrane cell three condenser, a membrane cell three pressure water tank and a membrane cell three suction pump connected in sequence, and further comprises a cooling tower and a cooling water circulating pump. The membrane cell one condenser, the membrane cell two condenser and the membrane cell three condenser are respectively connected with the membrane cell one condenser water outlet pipe, the membrane cell two condenser water outlet pipe and the membrane cell three condenser water outlet pipe, the membrane cell one condenser water outlet pipe, the membrane cell two condenser water outlet pipe and the membrane cell three condenser water outlet pipe are connected with the same pipeline and connected to the cooling tower, the membrane cell one condenser, the membrane cell two condenser and the membrane cell three condenser are respectively connected with the membrane cell one condenser water inlet pipe, the membrane cell two condenser water inlet pipe and the membrane cell three condenser water inlet pipe, the membrane cell one condenser water inlet pipe, the membrane cell two condenser water inlet pipe and the membrane cell three condenser water inlet pipe are connected with the same pipeline and connected to the cooling water circulating pump, and the cooling water circulating pump is connected with the cooling tower to form a circulation.

[0010] Preferably, the pipeline pump valve unit comprises a membrane pool one water inlet pipe, a membrane pool one water outlet pipe, a membrane pool one water production pipe, a membrane pool one water production pipe to water production tank pipeline, a membrane pool one and membrane pool two series pipeline, a membrane pool one and membrane pool two parallel pipeline, a membrane pool one backflow pipe, a membrane pool two water inlet pipe, a membrane pool two water outlet pipe, a membrane pool two water production pipe, a membrane pool two water production pipe to water production tank pipeline, a membrane pool two and membrane pool three series pipeline, a membrane pool two and membrane pool three parallel pipeline, a membrane pool two backflow pipe, a membrane pool three water inlet pipe, a membrane pool three water outlet pipe, a membrane pool three water production pipe, a membrane pool three water production pipe to water production tank pipeline, a membrane pool three backflow pipe; The membrane pool one is connected with the landfill leachate pressurizing pump through the membrane pool one water inlet pipe, the landfill leachate pressurizing pump is connected with the landfill leachate storage tank, and the landfill leachate storage tank is provided with a landfill leachate storage tank water inlet pipe and a landfill leachate storage tank backflow pipe, and the landfill leachate storage tank water inlet pipe is used for the landfill leachate to enter; The membrane pool one is connected with the membrane pool two through the membrane pool one water outlet pipe, the membrane pool one and membrane pool two parallel pipeline and the membrane pool two water inlet pipe connected in sequence, the membrane pool two is connected with the membrane pool three through the membrane pool two water outlet pipe, the membrane pool two and membrane pool three parallel pipeline and the membrane pool three water inlet pipe connected in sequence, and the membrane pool three is sequentially provided with the membrane pool three water outlet pipe and the membrane pool three backflow pipe; The membrane pool one backflow pipe is connected between the membrane pool one water outlet pipe and the membrane pool one and membrane pool two parallel pipeline, the membrane pool two backflow pipe is connected between the membrane pool two water outlet pipe and the membrane pool two and membrane pool three parallel pipeline, and the membrane pool one backflow pipe, the membrane pool two backflow pipe and the membrane pool three backflow pipe are connected with the same pipeline and connected to the landfill leachate storage tank backflow pipe; The membrane pool one and membrane pool two series pipeline is connected between the membrane pool one and membrane pool two parallel pipeline and the membrane pool two water inlet pipe, and the membrane pool two and membrane pool three series pipeline is connected between the membrane pool two and membrane pool three parallel pipeline and the membrane pool three water inlet pipe; The membrane pool one and membrane pool two series pipeline is connected with the membrane pool one suction pump and the membrane pool one water production pipe to water production tank pipeline, the membrane pool two and membrane pool three series pipeline is connected with the membrane pool two suction pump and the membrane pool two water production pipe to water production tank pipeline, the membrane pool three suction pump is connected with the membrane pool three water production pipe to water production tank pipeline, and the membrane pool one water production pipe to water production tank pipeline, the membrane pool two water production pipe to water production tank pipeline and the membrane pool three water production pipe to water production tank pipeline are connected with the same pipeline and connected to the water production tank, and the water production tank is connected with a water outlet.

[0011] Preferably, the temperature control process of the constant temperature water tank one, the constant temperature water tank two and the constant temperature water tank three is as follows: The self-use steam generated in the waste incineration process is transported into the steam heat exchanger through the steam pipeline to complete heat exchange and then discharge low-temperature steam, and the water in the pipeline is heated by the steam heat exchanger and then enters the constant-temperature water tank one, the constant-temperature water tank two and the constant-temperature water tank three through the constant-temperature water tank one water inlet pipe, the constant-temperature water tank two water inlet pipe and the constant-temperature water tank three water inlet pipe, wherein the constant-temperature water tank one water inlet pipe, the constant-temperature water tank two water inlet pipe and the constant-temperature water tank three water inlet pipe are provided with temperature control valves, the valve opening degree is adjusted according to the set temperature value to keep the temperature in the membrane pool one, the membrane pool two and the membrane pool three at the set temperature value; meanwhile, the water level in the constant-temperature water tank one, the constant-temperature water tank two and the constant-temperature water tank three is kept constant, and the water in the constant-temperature water tank one, the constant-temperature water tank two and the constant-temperature water tank three which has completed heat exchange is collected into the pipeline through the constant-temperature water tank one water outlet pipe, the constant-temperature water tank two water outlet pipe and the constant-temperature water tank three water outlet pipe and then is pressurized and circulated to the steam heat exchanger by the constant-temperature water tank backflow pump for recycling and heating.

[0012] Preferably, under the action of the saturated steam pressure difference formed by the temperature difference, the membrane distillation assembly one processes the landfill leachate in the membrane pool one, the membrane distillation assembly two processes the landfill leachate in the membrane pool two and the membrane distillation assembly three processes the landfill leachate in the membrane pool three; the process of the membrane distillation assembly one processing the landfill leachate is as follows: The constant-temperature water tank one keeps the temperature of the landfill leachate in the membrane pool one at the set temperature value, and there is a saturated steam pressure difference between the membrane distillation assembly one and the membrane pool one, and the steam on the membrane pool one side penetrates through the membrane holes of the membrane distillation assembly one under the action of the saturated steam pressure difference and enters the membrane pool one water production pipe, and the steam is condensed by the membrane pool one condenser, and the condensed water enters the membrane pool one pressure water production tank under the suction of the membrane pool one suction pump; The processes of the membrane distillation assembly two and the membrane distillation assembly three processing the landfill leachate are the same as the process of the membrane distillation assembly one processing the landfill leachate; The process of the membrane pool one condenser, the membrane pool two condenser and the membrane pool three condenser condensing and cooling is as follows: The water cooled by the cooling tower enters the membrane pool one condenser, the membrane pool two condenser and the membrane pool three condenser through the membrane pool one condenser water inlet pipe, the membrane pool two condenser water inlet pipe and the membrane pool three condenser water inlet pipe respectively, the membrane pool one condenser, the membrane pool two condenser and the membrane pool three condenser rapidly cool the steam inside to form water production, the water production is collected through the membrane pool one condenser water outlet pipe, the membrane pool two condenser water outlet pipe and the membrane pool three condenser water outlet pipe, and then enters the cooling tower for rapid cooling, and the cooled water is pressurized by the cooling water circulating pump and reenters the pipeline for recycling and condensing and cooling.

[0013] Preferably, the process of the parallel working condition of the membrane pool one and the membrane pool two is as follows: The leachate in the landfill leachate storage tank enters membrane tank one through the inlet pipe of membrane tank one. After treatment by membrane distillation module one, the concentrate enters membrane tank two through the outlet pipe of membrane tank one, the parallel pipeline of membrane tank one and membrane tank two, and the inlet pipe of membrane tank two. The raw water of membrane tank one enters membrane tank two. The two sets of membrane tanks operate in parallel. At this time, the status of pipeline pumps and valves is as follows: at the raw water / concentrate end, the valves on the outlet pipe of membrane tank one and the parallel pipeline of membrane tank one and membrane tank two are open, and the pumps and valves on the return pipe of membrane tank one are closed; at the outlet end, the valves on the pipeline from the product water pipe of membrane tank one to the product water tank are open, and the valves on the series pipeline of membrane tank one and membrane tank two are closed. The process of parallel operation of membrane tank three and membrane tank two is the same as that of parallel operation of membrane tank one and membrane tank two. In the parallel operation, two or three sets of membrane tanks jointly treat landfill leachate to increase the treatment area. The process of membrane tank one and membrane tank two operating in series is as follows: The leachate in the landfill storage tank enters Membrane Tank 1 through the inlet pipe of Membrane Tank 1. After treatment by Membrane Distillation Module 1, the permeate enters the condenser of Membrane Tank 1 through the permeate pipe of Membrane Tank 1 for condensation. Under the suction action of the suction pump of Membrane Tank 1, it enters the pressure permeate tank of Membrane Tank 1, and then enters Membrane Tank 2 through the series pipeline of Membrane Tank 1 and Membrane Tank 2, and the permeate of Membrane Tank 1 enters Membrane Tank 2. The two sets of membrane tanks operate in series. At this time, the status of the pipeline pump valves is: concentrate end, Membrane Tank 1 outlet pipe, Membrane Tank 1... The pump and valve on the return pipe are open, and the valve on the parallel pipe between membrane tank 1 and membrane tank 2 is closed. At the outlet, the valve on the series pipe between membrane tank 1 and membrane tank 2 is open, and the valve on the pipe from the permeate pipe of membrane tank 1 to the permeate tank is closed. The process of the series operation of membrane tank 3 and membrane tank 2 is the same as that of the series operation of membrane tank 1 and membrane tank 2. In the series operation, the latter set of membrane tanks further treats the leachate after the former set of membrane tanks has treated it. In the parallel operation of the three membrane tanks, the permeate from membrane tank 1, membrane tank 2, and membrane tank 3 is collected in the permeate tank after passing through the permeate pipes from membrane tank 1 to the permeate tank, membrane tank 2 to the permeate tank, and membrane tank 3 to the permeate tank. This is the effluent after parallel treatment. At this time, the status of the pipeline pumps and valves is as follows: On the permeate side, the valves on the permeate pipes from membrane tank 1 to the permeate tank, membrane tank 2 to the permeate tank, and membrane tank 3 to the permeate tank are open, while the valves on the series pipes between membrane tank 1 and membrane tank 2, and between membrane tank 2 and membrane tank 3 are closed. On the concentrate side, the pumps and valves on the return pipes of membrane tank 1 and membrane tank 2 are closed, while the pumps and valves on the return pipe of membrane tank 3 are open. In the case of three membrane tanks connected in series, the permeate from membrane tank 1 enters membrane tank 2 for treatment via the series pipeline connecting membrane tank 1 and membrane tank 2. The permeate from membrane tank 2 enters membrane tank 3 for treatment via the series pipeline connecting membrane tank 2 and membrane tank 3. The permeate from membrane tank 3 enters the permeate tank for storage via the permeate pipe from membrane tank 3, which is the effluent after series treatment. At this time, the status of the pipeline pumps and valves is as follows: On the permeate side, the valves on the series pipelines connecting membrane tank 1 and membrane tank 2, the series pipelines connecting membrane tank 2 and membrane tank 3, and the pipeline from the permeate pipe of membrane tank 3 to the permeate tank are open, while the valves on the pipelines from the permeate pipe of membrane tank 1 to the permeate tank and the pipeline from the permeate pipe of membrane tank 2 to the permeate tank are closed. On the concentrate side, the pumps and valves on the return pipes of membrane tank 1, membrane tank 2, and membrane tank 3 are all open.

[0014] Preferably, the low-carbon multi-stage membrane distillation bioreactor for treating landfill leachate is also equipped with a concentrate circulation pipeline, which returns the untreated concentrate from membrane tank 1, membrane tank 2, and membrane tank 3 to the landfill leachate storage tank via pumps and pipelines. Specifically, the concentrate circulation pipeline in the case of the three membrane tanks connected in series is a large circulation, in which the concentrate from membrane tank 1, membrane tank 2, and membrane tank 3 is circulated by a pump on the return pipe of membrane tank 3. The concentrate circulation pipeline in the case of the three membrane tanks connected in parallel is a small circulation, in which the concentrate from membrane tank 1, membrane tank 2, and membrane tank 3 is circulated by pumps on the return pipes of membrane tank 1, membrane tank 2, and membrane tank 3, respectively.

[0015] Therefore, the low-carbon multi-stage membrane distillation bioreactor for treating landfill leachate, which adopts the above-described structure, has the following beneficial effects: 1. The temperature control valve can be adjusted according to the set temperature value to maintain a constant temperature in each membrane tank, which is beneficial to the membrane distillation reaction process and microbial cultivation. 2. By switching pipeline pumps and valves, the series or parallel operation of multi-stage membrane distillation bioreactors can be freely and flexibly combined to meet actual water production needs. 3. Through the concentrate circulation pipeline, the untreated concentrate in each membrane tank is returned to the landfill leachate storage tank by water pumps and pipelines to reduce the accumulation of salt in the concentrate and avoid membrane pore fouling and blockage. 4. The multi-stage membrane distillation bioreactor provided by this invention maintains the membrane tank at medium and high temperature anaerobic digestion conditions, realizing an anaerobic membrane distillation bioreactor. While further improving the effluent quality, it can also collect methane gas generated during the anaerobic biological treatment of landfill leachate. 5. The multi-stage membrane distillation bioreactor provided by this invention is used as a treatment process for landfill leachate in waste incineration plants. All energy used is provided by the waste incineration plant, achieving complete energy self-sufficiency and green, low-carbon operation.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of an embodiment of a low-carbon multistage membrane distillation bioreactor for treating landfill leachate according to the present invention.

[0018] In the diagram: 1. Landfill leachate storage tank; 2. Landfill leachate pressurization pump; 3. Landfill leachate storage tank inlet pipe; 4. Landfill leachate storage tank return pipe; 5. Constant temperature water tank return water pump; 6. Steam heat exchanger; 7. High-temperature steam; 8. Low-temperature steam; 9. Product water tank; 10. Outlet pipe; 11. Membrane distillation module one; 12. Membrane tank one; 13. Constant temperature water tank one; 14. Constant temperature water tank one inlet pipe; 15. Constant temperature water tank one outlet pipe; 16. Membrane tank one inlet pipe; 17. Membrane tank one outlet pipe; 18. Membrane tank one product water pipe; 19. Membrane tank one exhaust pipe; 20. Membrane tank one condenser; 21. Membrane tank one pressurized product water. 22. Membrane Tank 1 Suction Pump; 23. Membrane Tank 1 Permeate Pipe to Permeate Tank; 24. Series Pipe Between Membrane Tank 1 and Membrane Tank 2; 25. Condenser Inlet Pipe Between Membrane Tank 1; 26. Condenser Outlet Pipe Between Membrane Tank 1; 27. Parallel Pipe Between Membrane Tank 1 and Membrane Tank 2; 28. Return Pipe Between Membrane Tank 1; 31. Membrane Distillation Module 2; 32. Membrane Tank 2; 33. Constant Temperature Water Tank 2; 34. Inlet Pipe of Constant Temperature Water Tank 2; 35. Outlet Pipe of Constant Temperature Water Tank 2; 36. Inlet Pipe of Membrane Tank 2; 37. Outlet Pipe of Membrane Tank 2; 38. Permeate Pipe of Membrane Tank 2; 39. Exhaust Pipe of Membrane Tank 2; 40. Condenser of Membrane Tank 2; 41. Pressure Permeate Tank of Membrane Tank 2; 42. Suction pump for membrane tank 2; 43. Pipeline from membrane tank 2 to product water tank; 44. Series connection between membrane tank 2 and membrane tank 3; 45. Condenser inlet pipe for membrane tank 2; 46. Condenser outlet pipe for membrane tank 2; 47. Parallel connection between membrane tank 2 and membrane tank 3; 48. Return pipe for membrane tank 2; 51. Membrane distillation module 3; 52. Membrane tank 3; 53. Constant temperature water tank 3; 54. Inlet pipe for constant temperature water tank 3; 55. Outlet pipe for constant temperature water tank 3; 56. Inlet pipe for membrane tank 3; 57. Outlet pipe for membrane tank 3; 58. Product water pipe for membrane tank 3; 59. Vent pipe for membrane tank 3; 60. Condenser for membrane tank 3; 61. Pressure product water tank for membrane tank 3; 62. 63. Membrane tank three-stage suction pump; 64. Membrane tank three-stage product water pipe to product water tank pipe; 65. Membrane tank three-stage condenser inlet pipe; 66. Membrane tank three-stage condenser outlet pipe; 67. Membrane tank three-stage return pipe; 71. Cooling tower; 72. Cooling water circulation pump; 73. Gas storage tank; 81. Garbage truck; 82. Garbage pit; 83. Grab bucket; 84. Incinerator; 85. Waste heat boiler; 86. Flue gas treatment device; 87. Bag filter; 88. Flue gas heater; 89. Chimney; 90. Steam; 91. Steam turbine generator; 92. High-voltage power grid; 93. Transformer; 94. Low-voltage electricity; 95. Landfill leachate; 96. Self-use steam. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0020] It should be noted that the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or server that includes a series of steps or units, not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0021] Similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use. They are only for the convenience of describing this invention and simplifying the description, 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 limiting this invention.

[0023] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] Example: like Figure 1As shown, the present invention discloses a low-carbon multi-stage membrane distillation bioreactor for treating landfill leachate, comprising a membrane treatment unit, a temperature control unit, a condensation and cooling unit, and a pipeline pump and valve unit. Its basic concept is as follows: landfill leachate is pumped into a membrane tank; the temperature control unit ensures a constant temperature in the membrane tank; steam is generated by the vapor pressure difference across the hydrophobic membrane, permeates through the membrane pores, and condenses into permeate water, thus achieving membrane separation; and by switching the pipeline pump and valve, the multi-stage membrane distillation bioreactor can be operated in series or parallel, thereby further improving the quality of the effluent.

[0025] like Figure 1 As shown, leachate 95 is generated during the waste incineration process. The specific process is as follows: garbage truck 81 transports municipal solid waste and unloads it into the waste pool 82 of the waste treatment plant for stacking and fermentation. The garbage is grabbed by grab bucket 83 and sent to incinerator 84 for high-temperature incineration. The high-temperature flue gas and heat enter the waste heat boiler 85 to generate steam 90. The flue gas then enters the flue gas treatment device 86 for treatment and enters the bag filter 87 to remove particulate matter and fly ash. After meeting the standards, it is heated by the flue gas heater 88 and discharged into the atmosphere through the chimney 89. The steam 90 enters the steam turbine generator 91 to generate electricity. The generated high-voltage electricity is directly connected to the high-voltage power grid 92. Part of the electricity is stepped down to low-voltage electricity 94 by transformer 93 for the plant's own use, and part of the steam is used as self-use steam 96 for the plant's own use. Both the waste pool 82 and the incinerator 84 will generate a large amount of leachate 95.

[0026] The membrane treatment unit includes a membrane distillation assembly 11, a membrane tank 12, a constant temperature water tank 13, a membrane distillation assembly 2 31, a membrane tank 2 32, a constant temperature water tank 2 33, a membrane distillation assembly 3 51, a membrane tank 3 52, and a constant temperature water tank 3 53. The temperature control unit includes a steam heat exchanger 6, a constant temperature water tank 1 inlet pipe 14, a constant temperature water tank 1 outlet pipe 15, a constant temperature water tank 2 inlet pipe 34, a constant temperature water tank 2 outlet pipe 35, a constant temperature water tank 3 inlet pipe 54, a constant temperature water tank 3 outlet pipe 55, and a constant temperature water tank return water pump 5. The condensation and cooling unit includes a condenser 20 for membrane tank 1, a pressure water production tank 21 for membrane tank 1, a suction pump 22 for membrane tank 1, a condenser 40 for membrane tank 2, a pressure water production tank 41 for membrane tank 2, a suction pump 42 for membrane tank 2, a condenser 60 for membrane tank 3, a pressure water production tank 61 for membrane tank 3, a suction pump 62 for membrane tank 3, a cooling tower 71, and a cooling water circulation pump 72. The pipeline pump and valve unit includes a membrane tank 1 inlet pipe 16, a membrane tank 1 outlet pipe 17, a membrane tank 1 product water pipe 18, a membrane tank 1 product water pipe to the product water tank 23, a series pipe 24 connecting membrane tank 1 and membrane tank 2, a parallel pipe 27 connecting membrane tank 1 and membrane tank 2, a membrane tank 1 return pipe 28, a membrane tank 2 inlet pipe 36, a membrane tank 2 outlet pipe 37, a membrane tank 2 product water pipe 38, a membrane tank 2 product water pipe to the product water tank 43, a series pipe 44 connecting membrane tank 2 and membrane tank 3, a parallel pipe 47 connecting membrane tank 2 and membrane tank 3, a membrane tank 2 return pipe 48, a membrane tank 3 inlet pipe 56, a membrane tank 3 outlet pipe 57, a membrane tank 3 product water pipe 58, a membrane tank 3 product water pipe to the product water tank 63, and a membrane tank 3 return pipe 67.

[0027] In this embodiment, the leachate 95 generated during the waste incineration process enters the leachate storage tank 1 through the leachate storage tank inlet pipe 3. After being pressurized by the leachate pressurization pump 2, it enters the membrane tank 12 through the membrane tank inlet pipe 16. The membrane tank 12 contains the membrane distillation assembly 11. The leachate storage tank 1 is also connected to the leachate storage tank return pipe 4.

[0028] In this embodiment, the membranes of membrane distillation assembly 11, membrane distillation assembly 2 31, and membrane distillation assembly 3 51 are all submerged hydrophobic microporous membranes made of polytetrafluoroethylene (PTFE), with a pore size of 0.2 μm and a water contact angle >120°.

[0029] In this embodiment, the membrane tank 12, membrane tank 2 32, and membrane tank 3 52 are respectively surrounded by constant temperature water tank 13, constant temperature water tank 2 33, and constant temperature water tank 3 53, which provide relatively constant temperature conditions for membrane tank 12, membrane tank 2 32, and membrane tank 3 52, so as to facilitate the membrane distillation reaction process and microbial culture.

[0030] In this embodiment, the specific process of temperature control for constant temperature water tank 13, constant temperature water tank 23, and constant temperature water tank 353 is as follows: the self-use steam 96 generated during the waste incineration process is transported through the steam pipeline to the steam heat exchanger 6 via high-temperature steam 7. After heat exchange, low-temperature steam 8 is discharged. The water in the pipeline is heated by the steam heat exchanger 6 and then enters constant temperature water tank 13, constant temperature water tank 23, and constant temperature water tank 353 via the constant temperature water tank inlet pipe 14, constant temperature water tank 234, and constant temperature water tank 354. The valves installed on the constant temperature water tank inlet pipe 14, constant temperature water tank 234, and constant temperature water tank 354 are temperature control valves. The valve opening can be adjusted according to the set temperature value to control the water inlet flow and temperature of the water tank, thereby keeping the temperature in membrane tank 12, membrane tank 232, and membrane tank 352 relatively constant near the set temperature value. Meanwhile, the water levels in constant temperature water tank 13, constant temperature water tank 23, and constant temperature water tank 33 are kept constant. The water that has completed heat exchange in the water tanks is collected through the outlet pipes 15, 35, and 55 of constant temperature water tank 1 and 3 and then pressurized by the constant temperature water tank return water pump 5 and circulated to the steam heat exchanger 6 for heating.

[0031] In this embodiment, under the action of the saturated vapor pressure difference formed by the temperature difference, membrane distillation module 11 treats the landfill leachate 95 in membrane tank 12. The specific process of membrane distillation module 11 is as follows: the constant temperature water tank 13 keeps the landfill leachate 95 in membrane tank 12 at a set temperature value, and there is a saturated vapor pressure difference between the leachate 95 and the product water side of membrane distillation module 11. The vapor on the membrane tank 12 side is driven by the saturated vapor pressure difference to pass through the membrane pores of membrane distillation module 11 and enter the product water pipe 18 of membrane tank 1. The vapor is condensed by membrane tank 1 condenser 20. The condensed water enters membrane tank 1 pressure product water tank 21 under the suction action of membrane tank 1 suction pump 22. The specific processes of membrane distillation module 2 31 and membrane distillation module 3 51 are basically the same as those of membrane distillation module 11, but the quality of the treated raw water may not be exactly the same.

[0032] In this embodiment, the specific condensation and cooling process of the membrane tank condenser 20, membrane tank condenser 40, and membrane tank condenser 60 is as follows: After being cooled by the cooling tower 71, the water enters the membrane tank condenser 20, membrane tank condenser 40, and membrane tank condenser 60 through the inlet pipe 25 of the membrane tank condenser 1, the inlet pipe 45 of the membrane tank condenser 20, and the inlet pipe 65 of the membrane tank condenser 3, respectively. The membrane tank condenser 20, membrane tank condenser 40, and membrane tank condenser 60 are spiral condenser tubes, which can quickly cool the steam in the condenser to form water. After passing through the condenser, the water is collected through the outlet pipe 26 of the membrane tank condenser 1, the outlet pipe 46 of the membrane tank condenser 2, and the outlet pipe 66 of the membrane tank condenser 3, and then enters the cooling tower 71 for rapid cooling. The cooled water is then pressurized by the cooling water circulation pump 72 and re-enters the pipeline for cyclic condensation and cooling.

[0033] In this embodiment, the switching of pipeline pumps and valves can achieve a free and flexible combination of series or parallel operation of multi-stage membrane distillation bioreactors to meet actual water production needs.

[0034] In this embodiment, the specific process of the parallel operation of the membrane distillation bioreactor is as follows: the leachate 95 in the landfill leachate storage tank 1 enters the membrane tank 12 through the inlet pipe 16 of the membrane tank 1. After being treated by the membrane distillation module 11, the concentrate enters the membrane tank 22 through the outlet pipe 17 of the membrane tank 1, the parallel pipe 27 connecting the membrane tank 1 and the membrane tank 2, and the inlet pipe 36 of the membrane tank 2. That is, the raw water of the membrane tank 12 enters the membrane tank 22, and the two sets of membrane tanks operate in parallel. At this time, the status of the pipeline pumps and valves is as follows: at the raw water / concentrate end, the valves on the outlet pipe 17 of the membrane tank 1 and the parallel pipe 27 connecting the membrane tank 1 and the membrane tank 2 are open, and the pump and valves on the return pipe 28 of the membrane tank 1 are closed; at the outlet end, the valves on the pipe 23 from the product water pipe of the membrane tank 1 to the product water tank are open, and the valves on the series pipe 24 connecting the membrane tank 1 and the membrane tank 2 are closed. Similarly, membrane tank 3 (52) can also be operated in parallel with membrane tank 2 (32) by turning on and off the corresponding water pumps and valves. In parallel operation, two or three sets of membrane tanks can jointly treat landfill leachate 95, which can increase the treatment area and improve the effluent flow rate.

[0035] In this embodiment, the specific process of the series operation of the membrane distillation bioreactor is as follows: the landfill leachate 95 in the landfill leachate storage tank 1 enters the membrane tank 12 through the inlet pipe 16 of the membrane tank 1. After being treated by the membrane distillation module 11, the permeate enters the membrane tank 1 condenser 20 through the permeate pipe 18 of the membrane tank 1 and is condensed. Under the suction action of the membrane tank 1 suction pump 22, it enters the membrane tank 1 pressure permeate tank 21 and enters the membrane tank 22 through the series pipe 24 of the membrane tank 1 and the inlet pipe 36 of the membrane tank 2. That is, the permeate of the membrane tank 12 enters the membrane tank 22, and the two sets of membrane tanks are operated in series. At this time, the status of the pipeline pumps and valves is as follows: At the concentrate end, the pumps and valves on the outlet pipe 17 and return pipe 28 of membrane tank 1 are open, while the valves on the parallel pipe 27 connecting membrane tank 1 and membrane tank 2 are closed; at the outlet end, the valves on the series pipe 24 connecting membrane tank 1 and membrane tank 2 are open, while the valves on the permeate pipe 23 from membrane tank 1 to the permeate tank are closed. Similarly, membrane tank 3 52 can also be operated in series with membrane tank 2 32 by opening and closing the corresponding pumps and valves. In series operation, the latter membrane tank further treats the leachate 95 treated by the former membrane tank, further improving the treated water quality.

[0036] In this embodiment, under the parallel operation of the three membrane tanks, the permeate from membrane tank 1 (12), membrane tank 2 (32), and membrane tank 3 (52) is collected via the permeate pipe from membrane tank 1 to permeate tank 23, the permeate pipe from membrane tank 2 to permeate tank 43, and the permeate pipe from membrane tank 3 to permeate tank 63, and then enters the permeate tank 9 for storage, which is the effluent after parallel treatment (discharged through the effluent pipe 10). At this time, the status of the pipeline pumps and valves is as follows: On the permeate side, the valves on the permeate pipes from membrane tank 1 to permeate tank 23, membrane tank 2 to permeate tank 43, and membrane tank 3 to permeate tank 63 are open, and the valves on the series pipes 24 (membrane tank 1 and membrane tank 2) and 44 (membrane tank 2 and membrane tank 3) are closed; on the concentrate side, the pumps and valves on the return pipes 28 (membrane tank 1) and 48 (membrane tank 2) are closed, and the pump and valves on the return pipe 67 (membrane tank 3) are open.

[0037] In this embodiment, under the condition of three sets of membrane tanks connected in series, the permeate from membrane tank 12 enters membrane tank 22 for treatment via the series pipe 24 connecting membrane tank 1 and membrane tank 2. The permeate from membrane tank 22 enters membrane tank 32 for treatment via the series pipe 44 connecting membrane tank 2 and membrane tank 3. The permeate from membrane tank 32 enters permeate tank 9 for storage via the permeate pipe 63 connecting permeate pipe 3, which is the effluent after series treatment (discharged through effluent pipe 10). At this time, the status of pipeline pumps and valves is as follows: On the permeate side, the valves on the series pipes 24 connecting membrane tank 1 and membrane tank 2, the series pipes 44 connecting membrane tank 2 and membrane tank 3, and the permeate pipe 63 connecting membrane tank 3 are open; the valves on the permeate pipes 23 connecting membrane tank 1 and membrane tank 2 and the permeate pipe 43 connecting membrane tank 2 are closed. On the concentrate side, the pumps and valves on the return pipes 28 connecting membrane tank 1, 48 connecting membrane tank 2, and 67 connecting membrane tank 3 are all open.

[0038] In this embodiment, to reduce salt accumulation in the concentrate and avoid membrane pore fouling and blockage, a concentrate circulation pipeline is provided. The untreated concentrate from membrane tank 12, membrane tank 232, and membrane tank 352 is returned to the landfill leachate storage tank 1 via a water pump and pipeline. Specifically, the concentrate circulation pipeline in the case of the three membrane tanks connected in series is a large circulation, and the concentrate from membrane tank 12, membrane tank 232, and membrane tank 352 is circulated by a water pump on the return pipe 67 of membrane tank 3. The concentrate circulation pipeline in the case of the three membrane tanks connected in parallel is a small circulation, and the concentrate from membrane tank 12, membrane tank 232, and membrane tank 352 is circulated by water pumps on the return pipe 28 of membrane tank 1, the return pipe 48 of membrane tank 2, and the return pipe 67 of membrane tank 3, respectively.

[0039] In this embodiment, if it is necessary to operate under the conditions of two sets of membrane tanks connected in series, one set of membrane tanks connected in parallel, or two sets of membrane tanks connected in parallel and one set of membrane tanks connected in series, the corresponding water pumps and valves can be turned on and off.

[0040] In this embodiment, there are three sets of membrane tanks: membrane tank 12, membrane tank 2 32, and membrane tank 3 52. If more sets of membrane tanks are needed, they can be combined using the same connection method to achieve the series and parallel operation of the multi-stage membrane distillation bioreactor.

[0041] In this embodiment, membrane tank 12, membrane tank 2 32, and membrane tank 3 52 are all equipped with gas collection. The gas generated by the microbial reaction process in membrane tank 12, membrane tank 2 32, and membrane tank 3 52, as well as the gas of the landfill leachate 95 itself, are collected through the exhaust pipe 19 of membrane tank 1, the exhaust pipe 39 of membrane tank 2, and the exhaust pipe 59 of membrane tank 3, and then enter the gas storage tank 73 for storage.

[0042] In this embodiment, the temperature control valves on the constant temperature water tank inlet pipe 14, constant temperature water tank inlet pipe 34, and constant temperature water tank inlet pipe 54 can keep the temperature in membrane tank 12, membrane tank 2 32, and membrane tank 3 52 relatively constant near different set temperature values ​​according to the needs of biological reaction and membrane distillation reaction conditions in the membrane tank.

[0043] In this embodiment, the temperature difference between the feed water end and the product water end of the membrane distillation module is positively correlated with the membrane product water flux. Experimental results show that when the membrane tank 12 is operated at 65°C by controlling the temperature of the constant temperature water tank 13, the flux of the membrane distillation module 11 is 25% higher than when it is operated at 55°C.

[0044] In this embodiment, the membrane tank is kept in an anaerobic state, and the temperature of the membrane tank is controlled at medium temperature (30~40℃) and high temperature (50~60℃) by a constant temperature water tank to achieve medium and high temperature anaerobic digestion conditions, thereby realizing an anaerobic membrane distillation bioreactor. This further improves the quality of the effluent and can collect the methane gas generated during the anaerobic biological treatment of landfill leachate 95. The experimental results show that, under the parallel operation of the three-stage membrane distillation bioreactor, when membrane tanks 12, 32, and 52 are controlled at 45℃, 55℃, and 65℃ respectively by constant temperature water tanks 1-13, 33-33, and 53 respectively, after stable operation, the COD removal rate of the permeate from membrane distillation modules 1-11, 31-31, and 51 is all above 98%, the ammonia nitrogen removal rates are 92%, 85%, and 88% respectively, the gas production rates are 1.2, 6.2, and 11.3 L gas / L permeate, and the methane content in the permeate is 51%, 60%, and 67% respectively. The treated effluent meets the relevant standards for reclaimed water and can be used for purposes such as cooling water.

[0045] In this embodiment, the multi-stage membrane distillation bioreactor is used as a treatment process for leachate in a waste incineration plant. All energy is provided by the waste incineration process, achieving complete energy self-sufficiency and green, low-carbon operation. Specifically, the membrane distillation process is driven by temperature difference. The membrane tank heats the constant temperature water tank through a steam heat exchanger 6 to maintain a constant temperature. The heat source 7 of the steam heat exchanger 6 comes from the self-used steam 96 generated during the waste incineration process. All water pumps, temperature control valves, valves, etc. in the system are powered by the steam 90 generated by the waste heat boiler 85, which enters the steam turbine generator 91 to generate electricity. The electricity is then stepped down by the transformer 93 to produce low-voltage electricity 94, without the need for additional energy consumption. Except for a small amount of evaporation and leakage, most of the heating water and condensate cooling water are recycled and reused.

[0046] Therefore, the present invention provides a low-carbon multi-stage membrane distillation bioreactor for treating landfill leachate using the above-mentioned structure. While solving the problems of membrane fouling due to salt accumulation, low treatment efficiency, unstable effluent quality, and high thermal energy consumption caused by single membrane distillation technology, it also provides a method and apparatus for treating landfill leachate with high treatment efficiency, good effluent quality, energy self-sufficiency, high methane recovery rate, and the ability to control reactor temperature as needed and to freely and flexibly switch between multiple stages. It has great potential in landfill leachate treatment and resource utilization.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A low-carbon multi-stage membrane distillation bioreactor for treating landfill leachate, characterized by, It comprises: a membrane treatment unit, which pumps the landfill leachate into a membrane pool, realizes membrane separation by condensing the steam into product water after the steam permeates through the membrane holes due to the vapor pressure difference between the two sides of the hydrophobic membrane; a temperature control unit, which keeps the membrane treatment unit at constant temperature; a condensation cooling unit, which condenses the steam into product water after it permeates through the membrane holes; a pipeline pump valve unit, which realizes the combination of series and parallel operation conditions of the multi-stage membrane distillation bioreactor by switching the pipeline pump valve.

2. The low-carbon multistage membrane distillation bioreactor for treating landfill leachate according to claim 1, characterized in that: The membrane treatment unit comprises membrane distillation assembly one, membrane pool one, constant temperature water tank one, membrane distillation assembly two, membrane pool two, constant temperature water tank two, membrane distillation assembly three, membrane pool three and constant temperature water tank three. Membrane distillation assembly one, membrane distillation assembly two and membrane distillation assembly three are arranged in membrane pool one, membrane pool two and membrane pool three respectively, and constant temperature water tank one, constant temperature water tank two and constant temperature water tank three are arranged outside membrane pool one, membrane pool two and membrane pool three respectively to provide constant temperature conditions for membrane pool one, membrane pool two and membrane pool three. Membrane pool one, membrane pool two and membrane pool three are connected with membrane pool one exhaust pipe, membrane pool two exhaust pipe and membrane pool three exhaust pipe respectively, and the membrane pool one exhaust pipe, membrane pool two exhaust pipe and membrane pool three exhaust pipe are connected with the same pipeline and connected to the gas storage tank.

3. The low-carbon multistage membrane distillation bioreactor for treating landfill leachate according to claim 2, characterized in that: The membranes of membrane distillation assembly one, membrane distillation assembly two and membrane distillation assembly three are all immersed hydrophobic microporous membranes made of polytetrafluoroethylene (PTFE) with a pore size of 0.2 μm and a water contact angle of >120°.

4. The low-carbon multistage membrane distillation bioreactor for treating landfill leachate according to claim 2, characterized in that: The temperature control unit comprises a steam heat exchanger, constant temperature water tank one inlet pipe, constant temperature water tank one outlet pipe, constant temperature water tank two inlet pipe, constant temperature water tank two outlet pipe, constant temperature water tank three inlet pipe, constant temperature water tank three outlet pipe and constant temperature water tank backflow pump. Constant temperature water tank one, constant temperature water tank two and constant temperature water tank three are connected with constant temperature water tank one inlet pipe, constant temperature water tank two inlet pipe and constant temperature water tank three inlet pipe respectively, and the constant temperature water tank one inlet pipe, constant temperature water tank two inlet pipe and constant temperature water tank three inlet pipe are connected with the same pipeline and connected to the steam heat exchanger; constant temperature water tank one, constant temperature water tank two and constant temperature water tank three are connected with constant temperature water tank one outlet pipe, constant temperature water tank two outlet pipe and constant temperature water tank three outlet pipe respectively, and the constant temperature water tank one outlet pipe, constant temperature water tank two outlet pipe and constant temperature water tank three outlet pipe are connected with the same pipeline and connected to the constant temperature water tank backflow pump; and the constant temperature water tank backflow pump is connected with the steam heat exchanger.

5. The low-carbon multistage membrane distillation bioreactor for treating landfill leachate according to claim 4, characterized in that: The condensation cooling unit comprises membrane pool one condenser, membrane pool one pressure product water tank and membrane pool one suction pump connected in sequence, membrane pool two condenser, membrane pool two pressure product water tank and membrane pool two suction pump connected in sequence, membrane pool three condenser, membrane pool three pressure product water tank and membrane pool three suction pump connected in sequence, cooling tower and cooling water circulating pump. The membrane pool one condenser, the membrane pool two condenser and the membrane pool three condenser are connected with the membrane pool one condenser water outlet pipe, the membrane pool two condenser water outlet pipe and the membrane pool three condenser water outlet pipe respectively, the membrane pool one condenser water outlet pipe, the membrane pool two condenser water outlet pipe and the membrane pool three condenser water outlet pipe are connected with the same pipeline and connected to the cooling tower, the membrane pool one condenser, the membrane pool two condenser and the membrane pool three condenser are connected with the membrane pool one condenser water inlet pipe, the membrane pool two condenser water inlet pipe and the membrane pool three condenser water inlet pipe respectively, the membrane pool one condenser water inlet pipe, the membrane pool two condenser water inlet pipe and the membrane pool three condenser water inlet pipe are connected with the same pipeline and connected to the cooling water circulating pump, and the cooling water circulating pump is connected with the cooling tower to form a circulation.

6. The low-carbon multistage membrane distillation bioreactor for treating landfill leachate according to claim 5, characterized in that: The pipeline pump valve unit comprises a membrane pool one water inlet pipe, a membrane pool one water outlet pipe, a membrane pool one water production pipe, a membrane pool one water production pipe to water production tank pipeline, a membrane pool one and membrane pool two series pipeline, a membrane pool one and membrane pool two parallel pipeline, a membrane pool one backflow pipe, a membrane pool two water inlet pipe, a membrane pool two water outlet pipe, a membrane pool two water production pipe, a membrane pool two water production pipe to water production tank pipeline, a membrane pool two and membrane pool three series pipeline, a membrane pool two and membrane pool three parallel pipeline, a membrane pool two backflow pipe, a membrane pool three water inlet pipe, a membrane pool three water outlet pipe, a membrane pool three water production pipe, a membrane pool three water production pipe to water production tank pipeline and a membrane pool three backflow pipe. The membrane pool one is connected with the landfill leachate pressurizing pump through the membrane pool one water inlet pipe, the landfill leachate pressurizing pump is connected with the landfill leachate storage tank, and the landfill leachate storage tank is connected with a landfill leachate storage tank water inlet pipe and a landfill leachate storage tank backflow pipe; the landfill leachate storage tank water inlet pipe is used for the landfill leachate to enter. The membrane pool one is connected with the membrane pool two through the membrane pool one water outlet pipe, the membrane pool one and membrane pool two parallel pipeline and the membrane pool two water inlet pipe connected in sequence, the membrane pool two is connected with the membrane pool three through the membrane pool two water outlet pipe, the membrane pool two and membrane pool three parallel pipeline and the membrane pool three water inlet pipe connected in sequence, and the membrane pool three is sequentially connected with the membrane pool three water outlet pipe and the membrane pool three backflow pipe. The membrane pool one backflow pipe is connected between the membrane pool one water outlet pipe and the membrane pool one and membrane pool two parallel pipeline, the membrane pool two backflow pipe is connected between the membrane pool two water outlet pipe and the membrane pool two and membrane pool three parallel pipeline, and the membrane pool one backflow pipe, the membrane pool two backflow pipe and the membrane pool three backflow pipe are connected with the same pipeline and connected to the landfill leachate storage tank backflow pipe. The membrane pool one and membrane pool two series pipeline is connected between the membrane pool one and membrane pool two parallel pipeline and the membrane pool two water inlet pipe, and the membrane pool two and membrane pool three series pipeline is connected between the membrane pool two and membrane pool three parallel pipeline and the membrane pool three water inlet pipe. The membrane pool one and membrane pool two series pipeline is connected with the membrane pool one suction pump and the membrane pool one water production pipe to water production tank pipeline respectively, the membrane pool two and membrane pool three series pipeline is connected with the membrane pool two suction pump and the membrane pool two water production pipe to water production tank pipeline respectively, the membrane pool three suction pump is connected with the membrane pool three water production pipe to water production tank pipeline, and the membrane pool one water production pipe to water production tank pipeline, the membrane pool two water production pipe to water production tank pipeline and the membrane pool three water production pipe to water production tank pipeline are connected with the same pipeline and connected to the water production tank, and the water production tank is connected with a water outlet.

7. The low-carbon multistage membrane distillation bioreactor for treating landfill leachate according to claim 6, characterized in that: The temperature control process of the constant temperature water tank one, the constant temperature water tank two and the constant temperature water tank three is as follows: The self-use steam generated in the waste incineration process is transported into the steam heat exchanger through the steam pipeline to output low-temperature steam after heat exchange, and the water in the pipeline is heated by the steam heat exchanger and then enters the constant-temperature water tank one, the constant-temperature water tank two and the constant-temperature water tank three through the constant-temperature water tank one water inlet pipe, the constant-temperature water tank two water inlet pipe and the constant-temperature water tank three water inlet pipe, wherein the constant-temperature water tank one water inlet pipe, the constant-temperature water tank two water inlet pipe and the constant-temperature water tank three water inlet pipe are provided with temperature control valves to adjust the valve opening degree according to the set temperature value, so that the temperature in the membrane pool one, the membrane pool two and the membrane pool three is maintained at the set temperature value; meanwhile, the water level in the constant-temperature water tank one, the constant-temperature water tank two and the constant-temperature water tank three is kept constant, and the water in the constant-temperature water tank one, the constant-temperature water tank two and the constant-temperature water tank three that has completed heat exchange is collected through the constant-temperature water tank one water outlet pipe, the constant-temperature water tank two water outlet pipe and the constant-temperature water tank three water outlet pipe, and then is pressurized and circulated to the steam heat exchanger by the constant-temperature water tank backflow pump for recycling and heating.

8. The low-carbon multistage membrane distillation bioreactor for treating landfill leachate according to claim 6, characterized in that: Under the action of the saturated steam pressure difference formed by the temperature difference, the membrane distillation assembly one processes the landfill leachate in the membrane pool one, the membrane distillation assembly two processes the landfill leachate in the membrane pool two, and the membrane distillation assembly three processes the landfill leachate in the membrane pool three; the process of the membrane distillation assembly one processing the landfill leachate is as follows: The constant-temperature water tank one keeps the landfill leachate in the membrane pool one at the set temperature value, and there is a saturated steam pressure difference between the membrane distillation assembly one and the water production side of the membrane pool one, so that the steam on the one side of the membrane pool one penetrates through the membrane holes of the membrane distillation assembly one under the action of the saturated steam pressure difference and enters the membrane pool one water production pipe, and the steam is condensed by the membrane pool one condenser, and the condensed water enters the membrane pool one pressure water tank under the suction action of the membrane pool one suction pump; The processes of the membrane distillation assembly two and the membrane distillation assembly three processing the landfill leachate are the same as the process of the membrane distillation assembly one processing the landfill leachate; The condensation and cooling processes of the membrane pool one condenser, the membrane pool two condenser and the membrane pool three condenser are as follows: The water cooled by the cooling tower enters the membrane pool one condenser, the membrane pool two condenser and the membrane pool three condenser through the membrane pool one condenser water inlet pipe, the membrane pool two condenser water inlet pipe and the membrane pool three condenser water inlet pipe respectively, the membrane pool one condenser, the membrane pool two condenser and the membrane pool three condenser rapidly cool the internal steam to form water production, the water production is collected through the membrane pool one condenser water outlet pipe, the membrane pool two condenser water outlet pipe and the membrane pool three condenser water outlet pipe, and then enters the cooling tower for rapid cooling, and the cooled water is pressurized by the cooling water circulating pump and reenters the pipeline for recycling and condensation and cooling.

9. The low-carbon multistage membrane distillation bioreactor for treating landfill leachate according to claim 6, characterized in that: The parallel working condition process of the membrane pool one and the membrane pool two is as follows: The landfill leachate in the landfill leachate storage tank enters membrane pool one through the membrane pool one water inlet pipe, is treated by the membrane distillation assembly one, and then the concentrated water enters membrane pool two through the membrane pool one water outlet pipe, the membrane pool one and membrane pool two parallel pipe, and the membrane pool two water inlet pipe; the raw water in the membrane pool one enters the membrane pool two, and the two groups of membrane pools are in parallel operation; at this time, the pipeline pump valve state is: raw water / concentrated water end, the valve state of the membrane pool one water outlet pipe and the membrane pool one and membrane pool two parallel pipe is open, the water pump and valve state of the membrane pool one backflow pipe is closed; water outlet end, the valve state of the membrane pool one water production pipe to the water tank pipe is open, and the valve state of the membrane pool one and membrane pool two series pipe is closed; the parallel working condition process of the membrane pool three and the membrane pool two is the same as that of the membrane pool one and the membrane pool two; under the parallel working condition, the two groups or three groups of membrane pools jointly treat the landfill leachate to increase the treatment area; The series working condition process of the membrane pool one and the membrane pool two is as follows: The landfill leachate in the landfill leachate storage tank enters membrane pool one through the membrane pool one water inlet pipe, is treated by the membrane distillation assembly one, and then the concentrated water enters membrane pool two through the membrane pool one water outlet pipe, the membrane pool one and membrane pool two parallel pipe, and the membrane pool two water inlet pipe; the raw water in the membrane pool one enters the membrane pool two, and the two groups of membrane pools are in parallel operation; at this time, the pipeline pump valve state is: raw water / concentrated water end, the valve state of the membrane pool one water outlet pipe and the membrane pool one and membrane pool two parallel pipe is open, the water pump and valve state of the membrane pool one backflow pipe is closed; water outlet end, the valve state of the membrane pool one water production pipe to the water tank pipe is open, and the valve state of the membrane pool one and membrane pool two series pipe is closed; the parallel working condition process of the membrane pool three and the membrane pool two is the same as that of the membrane pool one and the membrane pool two; under the parallel working condition, the two groups or three groups of membrane pools jointly treat the landfill leachate to increase the treatment area; Under the parallel working condition of the three groups of membrane pools, the water produced by the membrane pool one, the membrane pool two and the membrane pool three is collected through the membrane pool one water production pipe to the water tank pipe, the membrane pool two water production pipe to the water tank pipe and the membrane pool three water production pipe to the water tank pipe, and then enters the water tank for storage, which is the water outlet after parallel treatment; at this time, the pipeline pump valve state is: water production end, the valve state of the membrane pool one water production pipe to the water tank pipe, the membrane pool two water production pipe to the water tank pipe and the membrane pool three water production pipe to the water tank pipe is open, and the valve state of the membrane pool one and membrane pool two series pipe and the membrane pool two and membrane pool three series pipe is closed; concentrated water side, the water pump and valve state of the membrane pool one backflow pipe and the membrane pool two backflow pipe is closed, and the water pump and valve state of the membrane pool three backflow pipe is open; In the three groups of membrane pool series connection working conditions, the water produced by the membrane pool one is treated by the membrane pool two through the membrane pool one and membrane pool two series connection pipeline, the water produced by the membrane pool two is treated by the membrane pool three through the membrane pool two and membrane pool three series connection pipeline, the water produced by the membrane pool three is stored in the water tank through the membrane pool three water production pipeline to the water tank pipeline, which is the effluent after series connection treatment; At this time, the pipeline pump valve state is: on the water production side, the valve state of the membrane pool one and membrane pool two series connection pipeline, the membrane pool two and membrane pool three series connection pipeline, the membrane pool three water production pipeline to the water tank pipeline is open, the valve state of the membrane pool one water production pipeline to the water tank pipeline, the membrane pool two water production pipeline to the water tank pipeline is closed; On the concentrated water side, the water pump and valve state of the membrane pool one reflux pipeline, the membrane pool two reflux pipeline, the membrane pool three reflux pipeline are all open.

10. The low-carbon multistage membrane distillation bioreactor for treating landfill leachate according to claim 9, characterized in that: The low-carbon multi-stage membrane distillation biological reactor for treating landfill leachate also has a concentrated water circulation pipeline, which returns the untreated concentrated water in the membrane pool one, the membrane pool two and the membrane pool three to the landfill leachate storage tank through the water pump and the pipeline, wherein the concentrated water circulation pipeline in the three groups of membrane pool series connection working conditions is a large circulation, and the concentrated water of the membrane pool one, the membrane pool two and the membrane pool three is circulated by the water pump on the membrane pool three reflux pipeline; The concentrated water circulation pipeline in the three groups of membrane pool parallel connection working conditions is a small circulation, and the concentrated water of the membrane pool one, the membrane pool two and the membrane pool three is respectively circulated by the water pump on the membrane pool one reflux pipeline, the membrane pool two reflux pipeline and the membrane pool three reflux pipeline.

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