Anaerobic ultrafiltration membrane bioreactor with external components

Abstract

The present invention provides an anaerobic ultrafiltration membrane bioreactor with an external component, comprising a reaction tank and an ultrafiltration membrane device, wherein the reaction tank is connected to a first water inlet pipe, the first water inlet pipe is provided with a first pump for pumping sewage into the reaction tank, a first water outlet pipe is connected between the reaction tank and the ultrafiltration membrane device, the first water outlet pipe is provided with a second pump for pumping treated sewage in the reaction tank into the ultrafiltration membrane device for filtration, a first reflux pipe is also connected between the reaction tank and the ultrafiltration membrane device, the first reflux pipe is used to return sludge filtered out by the ultrafiltration membrane device to the reaction tank, and an external water storage tank is also included.

Description

Technical Field

[0001] The invention relates to the technical field of bioreactors, and in particular to an anaerobic ultrafiltration membrane bioreactor with an external component. Background Art

[0002] With the emergence of climate change, water shortage, and energy resource scarcity, aerobic microbial treatment of municipal sewage has long been considered a relatively high-energy consumption process. Therefore, anaerobic membrane bioreactors that combine anaerobic technology and membrane separation have replaced the traditional sewage treatment method of "energy consumption in exchange for water quality".

[0003] With the development of sewage treatment technology, the bioreactors that have been launched include internal pressure external type, suction immersion type, suction external type, etc. Taking the suction external type as an example, the patent document with application number 2019113027503 discloses such an anaerobic ultrafiltration membrane bioreactor with external components. This type of bioreactor generally includes an anaerobic reactor, a tubular ultrafiltration membrane device, a membrane cleaning device, a biogas collection device, etc., and the working principle is roughly as follows: the wastewater enters the anaerobic reactor for anaerobic reaction, consumes most of the organic matter in the wastewater, that is, reduces the CCD concentration in the wastewater, and then passes through the external tubular ultrafiltration membrane device to filter out the clean water, so that the sludge with anaerobic biota can be recycled.

[0004] However, the tubular ultrafiltration membrane device needs to be cleaned after a period of use. The wastewater generated when cleaning the ultrafiltration membrane also contains certain anaerobic biota, which can cause environmental pollution if discharged directly. Therefore, the present application aims to reduce the cleaning frequency of the tubular ultrafiltration membrane device and proposes an anaerobic ultrafiltration membrane bioreactor with an external component. Summary of the invention

[0005] The present invention aims to solve the above technical problems and provides an anaerobic ultrafiltration membrane bioreactor with an external component.

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

[0007] An anaerobic ultrafiltration membrane bioreactor with an external component comprises a reaction tank and an ultrafiltration membrane device, wherein the reaction tank is connected to a first water inlet pipe, the first water inlet pipe is provided with a first pump for pumping sewage into the reaction tank, a first water outlet pipe is connected between the reaction tank and the ultrafiltration membrane device, the first water outlet pipe is provided with a second pump for pumping the treated sewage in the reaction tank into the ultrafiltration membrane device for filtration, a first reflux pipe is also connected between the reaction tank and the ultrafiltration membrane device, the first reflux pipe is used to return the sludge filtered out by the ultrafiltration membrane device to the reaction tank, and an external water storage tank is also included, the external water storage tank and the ultrafiltration membrane device are connected by a first inlet and outlet water pipe, the first inlet and outlet water pipe is provided with a pump for pumping clean water filtered out by the ultrafiltration membrane device into the external water storage tank or into the external water storage tank The clean water in the water tank is pumped into the third pump of the ultrafiltration membrane device. The external water storage tank and the ultrafiltration membrane device are also connected by a second return pipe merged into the first outlet pipe. The second return pipe is used to reversely discharge sewage discharged from the ultrafiltration membrane device into the external water storage tank. The second pump is arranged on a pipe section shared by the first outlet pipe and the second return pipe. Valves are arranged on the first water inlet pipe, the first outlet pipe, the first return pipe, the first inlet and outlet pipes, and the second return pipe. When the valve on the first outlet pipe is closed and the valves on the first inlet and outlet pipes and the second return pipe are opened, the second pump and the third pump are started together to reversely pump the clean water in the external water storage tank into the ultrafiltration membrane device for cleaning and then re-introducing it into the external water storage tank.

[0008] As an practicable manner, a filter housing with a cavity interlayer is provided in the external water storage tank, the periphery of the filter housing is in close contact with the inner wall of the external water storage tank to divide the interior of the external water storage tank into an upper water area and a lower water area, the pipe end of the first water inlet and outlet pipe penetrates through the side wall of the external water storage tank and then extends into the cavity interlayer of the filter housing, an upper sterilizing filter element is provided on the inner top of the filter housing, the upper sterilizing filter element is separated between the upper water area and the cavity interlayer of the filter housing, and the inner bottom of the filter housing is provided The lower sterilizing filter element is separated between the lower water area and the cavity interlayer of the filter housing. A transverse plate and a motor driving the transverse plate to move transversely are provided on the top of the external water storage tank. A transverse frame connected to the pipe end of the first water inlet and outlet pipe is provided at one end of the transverse plate located outside the tank. A transverse contact piece is provided at one end of the transverse plate located on the tank. A lifting contact piece cooperating with the transverse contact piece is slidably connected to the inner wall of the external water storage tank. The bottom of the lifting contact piece contacts the top of the filter housing through a lifting and lowering pressure ring. The clean water entering the external water storage tank enters the cavity interlayer of the filter housing and is filtered twice by the upper sterilizing filter element. When the valve on the first water outlet pipe is closed and the valves on the first water inlet and outlet pipe and the second return pipe are opened, the motor drives the transverse plate and the transverse frame to move transversely to bring the pipe end of the first water inlet and outlet pipe out of the cavity interlayer of the filter housing, and then drives the lifting contact member and the lifting and pressing ring to press the filter housing down to below the position corresponding to the pipe end of the first water inlet and outlet pipe. Then, the second pump and the third pump are started together to pump the clean water in the upper water area into the ultrafiltration membrane device for cleaning and then redirect it to the lower water area in the external water storage tank, and the speed of redirecting it to the external water storage tank is faster than the speed of the water in the lower water area passing through the lower sterilizing filter element and the upper sterilizing filter element and entering the upper water area, so that when water enters the lower water area, the filter housing returns to its position upward, and the motor returns the pipe end of the first inlet and outlet pipe to the cavity interlayer of the filter housing after the filter housing returns to its position.

[0009] As an practicable manner, the external water storage tank includes a box body, the inner side wall of the box body is provided with an upper limit piece and a lower limit piece arranged at an upper and lower interval, the end of the filter shell is slidably connected with a side frame, the side frame is located between the upper limit piece and the lower limit piece, an elastic body is provided between the side frame and the end of the filter shell, and a limit plate is provided on the top of the side frame.

[0010] As an implementable manner, a mounting port is provided on the top of the filter housing, the inner bottom of the filter housing is fixedly connected to the lower sterilizing filter element by a mounting piece, and the side of the upper sterilizing filter element is connected to the inner side of the mounting port by a fastener; an upper cover is provided above the mounting port, and the side of the upper cover is provided with a mounting ear fixedly connected to the top of the filter housing; a central pipe axis is provided on the top of the upper cover; an upper drainage interface is provided on the top of the upper cover, and the side of the upper drainage interface has a plurality of side holes, and a connecting portion is provided on the top of the upper drainage interface; a lower water inlet interface is provided at the bottom of the box body.

[0011] As an implementable manner, a mounting cavity is provided on one side of the filter housing, and a rolling body is rotatably connected inside the mounting cavity.

[0012] As an implementable manner, the valves on the first water inlet pipe, the first water outlet pipe, the first return pipe, the first inlet and outlet pipes, and the second return pipe are all solenoid valves.

[0013] As an implementable manner, ultrafiltration membrane end pressure sensors are provided on both the first water outlet pipe and the first return pipe near the ultrafiltration membrane device.

[0014] As an implementable manner, a stirring assembly is disposed inside the reaction tank, an emptying pipe is disposed on the side of the reaction tank near the bottom, and a valve body is disposed on the emptying pipe.

[0015] As an implementable manner, a gas-liquid separator is provided on the side of the reaction tank and near the top, and a gas pipeline is connected to the top of the gas-liquid separator.

[0016] Compared with the prior art, the present invention has the advantage of reducing the frequency of disassembling and cleaning the ultrafiltration membrane device compared with the traditional external attracting bioreactor. The ultrafiltration membrane device needs to be cleaned after being used for a period of time. There are also certain anaerobic biota in the sewage generated when cleaning the ultrafiltration membrane, and direct discharge will cause environmental pollution. The anaerobic ultrafiltration membrane bioreactor with an external component introduces an external water storage tank and various related pipelines. After the ultrafiltration membrane device has been used for a period of time, the large and small particles blocked in it can be reversely started by starting the second pump and the third pump. The two pumps work together to reversely pump the clean water in the external water storage tank into the ultrafiltration membrane device to clean it and then re-introduce it into the external water storage tank (non-clean water area). Therefore, the frequency of disassembling and cleaning the ultrafiltration membrane device is greatly reduced, and the internal part of the external water storage tank, which is easier to clean, is replaced by cleaning, and the cleaning frequency can be reduced by enlarging the external water storage tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the principle of one embodiment of the present invention;

[0018] Figure 2 A three-dimensional diagram of an external water storage tank according to an embodiment of the present invention;

[0019] Figure 3 A top view of an external water storage tank according to an embodiment of the present invention;

[0020] Figure 4 for Figure 3 Middle EE section view;

[0021] Figure 5 for Figure 4 Enlarged view of point F in the middle;

[0022] Figure 6 It is a three-dimensional schematic diagram of a water distribution plate inside an external water storage tank according to one embodiment of the present invention;

[0023] Figure 7 It is a schematic diagram of the overall structure of an external water storage tank according to one embodiment of the present invention;

[0024] Figure 8 A partial cross-sectional view of an external water storage tank according to an embodiment of the present invention.

[0025] In the figure: 1, reaction tank; 2, first pump; 3, second pump; 4, third pump; 5, external water storage tank; 8, ultrafiltration membrane device; 9, emptying pipe; 10, gas-liquid separator; 11, gas pipeline; 12, rolling body; 13, box; 14, upper limit piece; 15, lower limit piece; 16, lower water inlet interface; 17, upper water area; 18, lower water area; 19, filter housing; 20, installation port; 21, lower sterilizing filter element; 22, installation piece; 23, upper sterilizing filter element; 24 , fastener; 25, installation cavity; 26, upper cover; 27, installation ear; 28, central pipe axis; 29, upper drainage interface; 291, side hole; 292, connecting part; 30, side frame; 31, elastic body; 32, limit plate; 33, transverse plate; 34, motor; 35, transverse frame; 36, transverse contact piece; 37, lifting contact piece; 38, lifting pressure ring; a, first water inlet pipe; b, first water outlet pipe; c, first return pipe; d, first inlet and outlet pipes; e, second return pipe. DETAILED DESCRIPTION

[0026] The above and other embodiments and advantages of the present invention are described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments.

[0027] In one embodiment, Figure 1 shown.

[0028] The anaerobic ultrafiltration membrane bioreactor with external components provided in this embodiment includes a reaction tank 1 and an ultrafiltration membrane device 8, the reaction tank 1 is connected to a first water inlet pipe a, the first water inlet pipe a is provided with a first pump 2 for pumping sewage into the reaction tank 1, a first water outlet pipe b is connected between the reaction tank 1 and the ultrafiltration membrane device 8, the first water outlet pipe b is provided with a second pump 3 for pumping the treated sewage in the reaction tank 1 into the ultrafiltration membrane device 8 for filtration, a first reflux pipe c is also connected between the reaction tank 1 and the ultrafiltration membrane device 8, the first reflux pipe c is for returning the sludge filtered out by the ultrafiltration membrane device 8 to the reaction tank 1, and the external water storage tank 5 is also included, the external water storage tank 5 and the ultrafiltration membrane device 8 are connected by a first inlet and outlet water pipe d, the first inlet and outlet water pipe d is provided with a pump for pumping the clean water filtered out by the ultrafiltration membrane device 8 into the external water storage tank 5 The third pump 4 is used to pump the clean water in the external water tank 5 into the ultrafiltration membrane device 8. The external water tank 5 and the ultrafiltration membrane device 8 are also connected by a second return pipe e incorporated into the first outlet pipe b. The second return pipe e is used to reversely discharge the sewage discharged through the ultrafiltration membrane device 8 into the external water tank 5. The second pump 3 is arranged on a pipe section shared by the first outlet pipe b and the second return pipe e. Valves are arranged on the first inlet pipe a, the first outlet pipe b, the first return pipe c, the first inlet and outlet pipes d, and the second return pipe e. When the valve on the first outlet pipe b is closed and the valves on the first inlet and outlet pipes d and the second return pipe e are opened, the second pump 3 and the third pump 4 are started together to reversely pump the clean water in the external water tank 5 into the ultrafiltration membrane device 8 for cleaning and then re-introducing it into the external water tank 5.

[0029] In this embodiment, the bioreactor includes a reaction tank 1 and an ultrafiltration membrane device 8. The side of the reaction tank 1 has a first water inlet pipe a, which is used to pump sewage from the outside, generally sewage after sedimentation treatment, into the reaction tank 1. The first water inlet pipe a is provided with a first pump 2. When the first pump 2 works, it pumps external water into the reaction tank 1. A first water outlet pipe b and a first return pipe c are connected between the reaction tank 1 and the ultrafiltration membrane device 8. The first water outlet pipe b and the first return pipe c provide a circulation pipeline between the reaction tank 1 and the ultrafiltration membrane device 8, so that a mixture of sewage and sludge is sent into the ultrafiltration membrane device 8. After filtering the clean water, the dry sludge is returned to the reaction tank 1, thereby realizing the circulation of the anaerobic bacteria. The first water outlet pipe b is provided with a second pump 3. The second pump 3 is used to extract the sludge water in the reaction tank and pressurize it into the ultrafiltration membrane device 8.

[0030] The advantage of the bioreactor provided in this embodiment over the traditional external attracting bioreactor is that the frequency of disassembling and cleaning the ultrafiltration membrane device 8 is reduced, and the ultrafiltration membrane device 8 needs to be cleaned after being used for a period of time. There are also certain anaerobic biota in the sewage generated when cleaning the ultrafiltration membrane, and direct discharge will cause environmental pollution. In this embodiment, an external water storage tank 5 and various related pipelines are introduced. After the ultrafiltration membrane device 8 has been used for a period of time, the large and small particles blocked in it can be started by reverse starting the second pump 3 and the third pump 4. The two start together to reversely pump the clean water in the external water storage tank 5 into the ultrafiltration membrane device 8 to clean it and re-introduce it to the non-clean water area of ​​the external water storage tank 5. Therefore, the frequency of disassembling and cleaning the ultrafiltration membrane device 8 is greatly reduced, and it is replaced by cleaning the inside of the external water storage tank 5, which is easier to clean, and the external water storage tank 5 can be made larger to reduce the cleaning frequency.

[0031] In one embodiment, Figure 1 , Figure 4 , Figure 5 , Figure 7 , Figure 8 shown.

[0032] The anaerobic ultrafiltration membrane bioreactor with an external component provided in this embodiment has a filter housing 19 with a cavity interlayer in its external water storage tank 5, the periphery of the filter housing 19 is in close contact with the inner wall of the external water storage tank 5 to divide the interior of the external water storage tank 5 into an upper water area 17 and a lower water area 18, the pipe end of the first water inlet and outlet pipe d penetrates the side wall of the external water storage tank 5 and then extends into the cavity interlayer of the filter housing 19, the inner top of the filter housing 19 is provided with an upper sterilizing filter element 23, and the upper sterilizing filter element 23 is separated between the upper water area 17 and the cavity interlayer of the filter housing 19. The bottom of the filter housing 19 is provided with a lower sterilizing filter element 21, which is separated between the lower water area 18 and the cavity interlayer of the filter housing 19. A transverse plate 33 and a motor 34 for driving the transverse plate 33 to move transversely are provided on the top of the external water storage tank 5. The end of the transverse plate 33 located outside the box is provided with a transverse frame 35 connected to the pipe end of the first water inlet and outlet pipe d. The end of the transverse plate 33 located on the box is provided with a transverse contact member 36. The inner wall of the external water storage tank 5 is slidably connected with a lifting contact member 37 that cooperates with the transverse contact member 36. The bottom of the lifting contact member 37 is lifted by lifting pressure. The ring 38 abuts against the top of the filter housing 19; wherein, the clean water drawn into the external water storage tank 5 enters the cavity interlayer of the filter housing 19 and is filtered twice by the upper sterilizing filter element 23. When the valve on the first outlet pipe b is closed and the valves on the first inlet and outlet pipes d and the second return pipe e are opened, the motor 34 drives the transverse plate 33 and the transverse frame 35 to move transversely to bring out the pipe end of the first inlet and outlet pipe d from the cavity interlayer of the filter housing 19, and then drives the lifting contact member 36 and the lifting and pressing ring 38 to press the filter housing 19 down to the corresponding pipe end of the first inlet and outlet pipe d. The second pump 3 and the third pump 4 are started together to pump the clean water of the upper water area 17 into the ultrafiltration membrane device 8 for cleaning and then redirect it to the lower water area 18 in the external water storage tank 5, and the speed of redirecting it to the external water storage tank 5 is faster than the speed of the water in the lower water area 18 passing through the lower sterilizing filter element 21 and the upper sterilizing filter element 23 and entering the upper water area 17, so that when water enters the lower water area 18, the filter housing 19 returns to its position upward, and the motor 34 returns the pipe end of the first water inlet and outlet pipe d to the cavity interlayer of the filter housing 19 after the filter housing 19 returns to its position.

[0033] In this embodiment, the interior of the external water storage tank 5 is divided into an upper water area 17 and a lower water area 18 by the filter housing 19, wherein the upper water area 17 is a clean water area and the lower water area 18 is a sewage area. The water filtered by the ultrafiltration membrane device 8 is not completely clean and still contains a small number of small particles. Therefore, it is filtered twice by the filter housing 19. The specific flow direction of the water can be to flow into the upper water area 17 after passing through the upper sterilizing filter element 23, or to flow into the lower water area 18 after passing through the lower sterilizing filter element 21. In the actual working process, the water in the lower water area 18 will flow into the upper water area 17 after passing through the lower sterilizing filter element 21 and the upper sterilizing filter element 23. Specifically, if the cleaning procedure is to be activated, the valve on the first water outlet pipe b is closed, and the valve on the second return pipe e is opened, and the original flow path from the ultrafiltration membrane device 8 through the third pump 4 to the external water storage tank 5 is changed to the flow path from the external water storage tank 5 through the third pump 4 to the ultrafiltration membrane device 8. However, unlike the original flow path, in the cleaning process, the water does not originate from the cavity sandwich of the filter housing 19. Figure 7 , Figure 8As shown, when the valve on the first outlet pipe b is closed and the valves on the first inlet and outlet pipe d and the second return pipe e are opened, the motor 34 drives the transverse plate 33 and the transverse frame 35 to move transversely to bring out the pipe end of the first inlet and outlet pipe d from the cavity interlayer of the filter housing 19. Then, as the transverse plate 33 and the transverse frame 35 continue to move transversely, the transverse contact member 36 and the lifting contact member 37 cooperate to drive the lifting contact member 36 and the lifting and pressing ring 38 to press the filter housing 19 down to the position below the pipe end of the first inlet and outlet pipe d, that is, to make the pipe end of the first inlet and outlet pipe d face the upper water area 17. It should be noted that the close contact between the periphery of the filter housing 19 and the inner wall of the external water storage tank 5 is similar to a piston connection. During the pressing process of the filter housing 19, the area of ​​the upper water area 17 expands and the area of ​​the lower water area 18 shrinks, that is, the water in the aforementioned lower water area 18 flows into the upper water area 17 after passing through the lower sterilizing filter element 21 and the upper sterilizing filter element 23. The clean water filtered into the upper water area 17 is used to clean the ultrafiltration membrane device 8. After flushing, the water is led back to the lower water area 18 in the external water storage tank 5 by the action of the second pump 3. At this time, the speed of the water led back to the external water storage tank 5 is greater than the speed of the water in the lower water area 18 passing through the lower sterilizing filter element 21 and the upper sterilizing filter element 23 and entering the upper water area 17, so that when the water enters the lower water area 18, the filter housing 19 returns upward, and the motor 34 returns the pipe end of the first water inlet and outlet pipe d to the cavity interlayer of the filter housing 19 after the filter housing 19 returns to its position. This also means that a complete cleaning procedure is completed. Therefore, the anaerobic ultrafiltration membrane bioreactor with an external component provided in this embodiment can reduce the cleaning frequency of the external water storage tank 5, because sewage is introduced into the lower water area 18 and the upper water area 17 of clean water is reserved, and the water used to flush the ultrafiltration membrane device 8 each time is only taken from the upper water area 17. Therefore, a better cleaning effect can be obtained at the same time, because the water used to flush the ultrafiltration membrane device 8 has been filtered twice. The sewage generated by the two application scenarios is introduced into the cavity interlayer of the filter housing 19 and the lower water area 18 respectively. After long-term use, these two parts can be cleaned centrally.

[0034] In one embodiment, Figure 2 , Figure 4 shown.

[0035] The anaerobic ultrafiltration membrane bioreactor with external components provided in this embodiment has an external water storage tank 5 including a box body 13, the inner side wall of the box body 13 is provided with an upper limit member 14 and a lower limit member 15 which are spaced apart from each other, the end of the filter housing 19 is slidably connected with a side frame 30, the side frame 30 is located between the upper limit member 14 and the lower limit member 15, an elastic body 31 is provided between the side frame 30 and the end of the filter housing 19, and a limit plate 32 is provided on the top of the side frame 30.

[0036] In this embodiment, by using the elastic body 31 to fill the side frame 30, the side frame 30 can be made of rubber material to better fit the inner wall of the box body 13, and the upper limit member 14 and the lower limit member 15 can define the upper and lower range of motion of the filter housing 19. The sliding connection between the filter housing 19 and the side frame 30 is because the elastic body 31 is filled in the side frame 30, and as the side frame 30 wears, the elastic body 31 expands so that the side frame 30 can still fit the inner wall of the box body 13 closely.

[0037] In one embodiment, Figure 3-6 shown.

[0038] The anaerobic ultrafiltration membrane bioreactor with external components provided in this embodiment is provided with a mounting port 20 on the top of the filter housing 19, the inner bottom of the filter housing 19 is fixedly connected to the lower sterilizing filter element 21 by a mounting member 22, and the side of the upper sterilizing filter element 23 is connected to the inner side of the mounting port 20 by a fastener 24; an upper cover 26 is provided above the mounting port 20, and a mounting ear 27 fixedly connected to the top of the filter housing 19 is provided on the side of the upper cover 26; a central pipe axis 28 is provided on the top of the upper cover 26; an upper drainage interface 29 is provided on the top of the upper cover 26, and a plurality of side holes 291 are provided on the side of the upper drainage interface 29, and a connecting portion 292 is provided on the top of the upper drainage interface 29; a lower water inlet interface 16 is provided at the bottom of the box body 13.

[0039] In this embodiment, a specific connection structure of the lower sterilizing filter element 21 and a specific connection structure of the upper sterilizing filter element 23 are provided.

[0040] In other embodiments, a mounting cavity 25 is provided on one side of the filter housing 19 of the anaerobic ultrafiltration membrane bioreactor with an external component, and a rolling body 12 is rotatably connected inside the mounting cavity 25. The valves on the first water inlet pipe a, the first water outlet pipe b, the first return pipe c, the first water inlet and outlet pipes d, and the second return pipe e are all solenoid valves. The first water outlet pipe b and the first return pipe c are both provided with ultrafiltration membrane end pressure sensors near the ultrafiltration membrane device 8. A stirring component is provided inside the reaction tank 1, and an emptying pipe 9 is provided on the side of the reaction tank 1 and near the bottom, and a valve body is provided on the emptying pipe 9. A gas-liquid separator 10 is provided on the side of the reaction tank 1 and near the top, and a gas pipeline 11 is connected to the top of the gas-liquid separator 10.

[0041] The specific implementation methods described above further describe the invention purpose, technical solutions, and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the protection scope of the present invention. It is particularly pointed out that for those skilled in the art, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An anaerobic ultrafiltration membrane bioreactor with an external component, comprising a reaction tank (1) and an ultrafiltration membrane device (8), wherein the reaction tank (1) is connected to a first water inlet pipe (a), the first water inlet pipe (a) is provided with a first pump (2) for pumping sewage into the reaction tank (1), a first water outlet pipe (b) is connected between the reaction tank (1) and the ultrafiltration membrane device (8), the first water outlet pipe (b) is provided with a second pump (3) for pumping the treated sewage in the reaction tank (1) into the ultrafiltration membrane device (8) for filtration, a first return pipe (c) is further connected between the reaction tank (1) and the ultrafiltration membrane device (8), the first return pipe (c) is for returning sludge filtered out by the ultrafiltration membrane device (8) to the reaction tank (1), and characterized in that: The invention also comprises an external water storage tank (5), wherein the external water storage tank (5) and the ultrafiltration membrane device (8) are connected via a first water inlet and outlet pipe (d), and the first water inlet and outlet pipe (d) is provided with a third pump (4) for pumping clean water filtered by the ultrafiltration membrane device (8) into the external water storage tank (5) or for pumping clean water in the external water storage tank (5) into the ultrafiltration membrane device (8). The external water storage tank (5) and the ultrafiltration membrane device (8) are also connected via a first water outlet pipe (d) and a third pump (4) for pumping clean water filtered by the ultrafiltration membrane device (8) into the external water storage tank (5) or a third pump (4) for pumping clean water in the external water storage tank (5) into the ultrafiltration membrane device (8). The first water inlet pipe (a), the first water outlet pipe (b), the first return pipe (c), the first water inlet and outlet pipes (d), and the second return pipe (e) are all provided with valves; When the valve on the first water outlet pipe (b) is closed and the valves on the first water inlet and outlet pipes (d) and the second return pipe (e) are opened, the second pump (3) and the third pump (4) are started together to reversely pump the clean water in the external water storage tank (5) into the ultrafiltration membrane device (8) to clean it and then re-introduce it into the external water storage tank (5); The external water storage tank (5) is provided with a filter housing (19) having a cavity interlayer. The periphery of the filter housing (19) is in close contact with the inner wall of the external water storage tank (5) so as to divide the interior of the external water storage tank (5) into an upper water area (17) and a lower water area (18). The pipe end of the first water inlet and outlet pipe (d) penetrates through the side wall of the external water storage tank (5) and then extends into the cavity interlayer of the filter housing (19). The inner top of the filter housing (19) is provided with an upper sterilizing filter element (23), and the upper sterilizing filter element (23) is separated between the upper water area (17) and the cavity interlayer of the filter housing (19). The inner bottom of the filter housing (19) is provided with a lower sterilizing filter element (21). The lower sterilizing filter element (21) is separated between the lower water area (18) and the cavity interlayer of the filter housing (19); a transverse plate (33) and a motor (34) for driving the transverse plate (33) to move transversely are provided on the top of the external water storage tank (5); a transverse frame (35) connected to the pipe end of the first water inlet and outlet pipe (d) is provided on the end of the transverse plate (33) located outside the tank; a transverse contact piece (36) is provided on the end of the transverse plate (33) located on the tank; a lifting contact piece (37) cooperating with the transverse contact piece (36) is slidably connected to the inner wall of the external water storage tank (5); the bottom of the lifting contact piece (37) is in contact with the top of the filter housing (19) through a lifting pressure ring (38); The clean water drawn into the external water storage tank (5) enters the cavity interlayer of the filter housing (19) and is filtered twice through the upper sterilizing filter element (23). When the valve on the first water outlet pipe (b) is closed and the valves on the first water inlet and outlet pipes (d) and the second return pipe (e) are opened, the motor (34) drives the transverse plate (33) and the transverse frame (35) to move transversely to bring the pipe end of the first water inlet and outlet pipe (d) out of the cavity interlayer of the filter housing (19), and then drives the lifting contact member (37) and the lifting and pressing ring (38) to press the filter housing (19) down to a position below the pipe end of the first water inlet and outlet pipe (d), and then Afterwards, the second pump (3) and the third pump (4) are started together to pump clean water from the upper water area (17) in reverse into the ultrafiltration membrane device (8) to clean the clean water and then re-introduce the clean water into the lower water area (18) in the external water storage tank (5). The speed of the clean water re-introduced into the external water storage tank (5) is greater than the speed at which the water in the lower water area (18) passes through the lower sterilizing filter element (21) and the upper sterilizing filter element (23) and enters the upper water area (17). When water enters the lower water area (18), the filter housing (19) returns to its original position. After the filter housing (19) returns to its original position, the motor (34) returns the pipe end of the first water inlet and outlet pipe (d) to the cavity interlayer of the filter housing (19).

2. The anaerobic ultrafiltration membrane bioreactor with an external component according to claim 1, characterized in that: The external water storage tank (5) comprises a box body (13), the inner side wall of the box body (13) is provided with an upper limit piece (14) and a lower limit piece (15) arranged at an interval up and down, the end of the filter housing (19) is slidably connected with a side frame (30), the side frame (30) is located between the upper limit piece (14) and the lower limit piece (15), an elastic body (31) is provided between the side frame (30) and the end of the filter housing (19), and a limit plate (32) is provided on the top of the side frame (30).

3. The anaerobic ultrafiltration membrane bioreactor with an external component according to claim 2, characterized in that: The top of the filter housing (19) is provided with a mounting opening (20), the inner bottom of the filter housing (19) is fixedly connected to the lower sterilizing filter element (21) through a mounting piece (22), and the side of the upper sterilizing filter element (23) is connected to the inner side of the mounting opening (20) through a fastener (24); an upper cover (26) is provided above the mounting opening (20), and the side of the upper cover (26) is provided with a mounting ear (27) fixedly connected to the top of the filter housing (19); a central pipe axis (28) is provided at the top of the upper cover (26); an upper drainage interface (29) is provided at the top of the upper cover (26), and the side of the upper drainage interface (29) has a plurality of side holes (291), and a connecting portion (292) is provided at the top of the upper drainage interface (29); and a lower water inlet interface (16) is provided at the bottom of the box body (13).

4. The anaerobic ultrafiltration membrane bioreactor with an external component according to claim 3, characterized in that: A mounting cavity (25) is provided on one side of the filter housing (19), and a rolling body (12) is rotatably connected inside the mounting cavity (25).

5. The anaerobic ultrafiltration membrane bioreactor with an external component according to claim 1, characterized in that: The valves on the first water inlet pipe (a), the first water outlet pipe (b), the first return pipe (c), the first water inlet and outlet pipes (d), and the second return pipe (e) are all solenoid valves.

6. The anaerobic ultrafiltration membrane bioreactor with an external component according to claim 1, characterized in that: Ultrafiltration membrane end pressure sensors are provided on the first water outlet pipe (b) and the first return pipe (c) near the ultrafiltration membrane device (8).

7. The anaerobic ultrafiltration membrane bioreactor with an external component according to claim 1, characterized in that: A stirring assembly is arranged inside the reaction tank (1), an exhaust pipe (9) is arranged on the side of the reaction tank (1) and close to the bottom, and a valve body is arranged on the exhaust pipe (9).

8. The anaerobic ultrafiltration membrane bioreactor with an external component according to claim 1, characterized in that: A gas-liquid separator (10) is arranged on the side of the reaction tank (1) and close to the top, and a gas pipeline (11) is connected to the top of the gas-liquid separator (10).

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