MBR sewage treatment device and method

Abstract

The invention relates to the technical field of sewage treatment, in particular to an MBR sewage treatment device and method.The MBR sewage treatment device comprises a top plate, a bottom plate, a first aeration device, a second aeration device, a third aeration device, a first fixing chain, a fixing frame, an MBR aeration membrane assembly, a lower aeration body and a second fixing chain; the fixing frame is supported at the bottom of the oxidation ditch; the bottom plate is connected below the top plate through a first fixing chain, and the four groups of MBR aeration membrane assemblies are arranged between the top plate and the bottom plate and are respectively and sequentially sleeved on the outer side of the first aeration device, between the first aeration device and the second aeration device, between the second aeration device and the third aeration device and on the inner side of the third aeration device from outside to inside; the lower aeration body is arranged at the bottom of the oxidation ditch, and the top end of the lower aeration body is connected with the bottom end of the bottom plate through a second fixing chain. The MBR sewage treatment device and method can effectively reduce activated sludge attached to the membrane surface.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to an MBR wastewater treatment device and method. Background Technology

[0002] MBR (Membrane Bioreactor) is a new type of wastewater treatment technology that organically combines membrane separation technology and biological treatment technology. It boasts advantages such as high effluent quality, low residual sludge, and excellent nitrogen and phosphorus removal. MBR can be used in small-scale integrated wastewater treatment plants as well as in large-scale wastewater treatment processes. When upgrading existing oxidation ditch wastewater treatment processes, the principle is to minimize alterations and maintain continuous operation to ensure the effluent meets the requirements of the new standards. However, adding an MBR process to an oxidation ditch presents the following problems: 1. Activated sludge has a long cultivation cycle and cannot be drained, so aerators and membrane modules cannot be installed.

[0003] 2. Aeration below the membrane module can only clean the lower part of the MBR membrane module, while the cleaning effect on the middle and upper parts is poor, which leads to membrane fouling and clogging and shortens the backwashing interval.

[0004] 3. In the existing technology, the aeration device of the MBR membrane module has a simple structure and the oxygen dissolution efficiency of the generated bubbles is low. Summary of the Invention

[0005] The purpose of this invention is to provide an MBR wastewater treatment device and method, in which an MBR aeration membrane module is placed at the bottom of the oxidation ditch without drainage, causing the MBR aeration membrane module to deform and oscillate in multiple directions, effectively reducing the adhesion of activated sludge to the membrane surface and reducing membrane fouling, thereby solving the technical problems existing in the background art.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A micro-bioreactor (MBR) wastewater treatment device is installed at the bottom of an oxidation ditch in front of a flow booster. It comprises: a top plate, a bottom plate, a first aeration device, a second aeration device, a third aeration device, a first fixing chain, a fixing frame, an MBR aeration membrane assembly, a lower aeration gas supply, and a second fixing chain. The top plate is fixedly installed on the top of the fixing frame, which supports the bottom of the oxidation ditch. The bottom plate is connected to the bottom of the top plate via the first fixing chain. Four sets of MBR aeration membrane assemblies are arranged between the top and bottom plates, and are respectively nested from the outside to the inside of the outer side of the first aeration device, between the first and second aeration devices, between the second and third aeration devices, and inside the third aeration device. The lower aeration gas supply is located at the bottom of the oxidation ditch and fixedly connected to the fixing frame. The top of the lower aeration gas supply is connected to the bottom of the bottom plate via the second fixing chain.

[0007] Furthermore, both the first and second fixed chains are flexible bodies. The top and bottom ends of the first fixed chain are respectively fixedly connected to the bottom end of the top plate and the top end of the bottom plate; the top and bottom ends of the second fixed chain are respectively fixedly connected to the bottom end of the bottom plate and the top end of the aeration gas.

[0008] Furthermore, the bottom plate and the top plate have the same shape and each includes a body and a mounting body. Several mounting bodies are provided and are set on the body. The four sets of MBR aeration membrane modules are respectively installed between the top plate and the bottom plate through several mounting bodies. The MBR aeration membrane module is a curtain membrane and the overall cross-section is circular or U-shaped. Adjacent sets of MBR aeration membrane modules are spaced apart.

[0009] Furthermore, the top plate is provided with an air inlet pipe connected to the air source, and the air inlet pipe is also connected to the first aeration device, the second aeration device and the third aeration device respectively; the lower aeration gas is connected to the air source.

[0010] Furthermore, the first aeration device includes: external aeration pipes and an outer baffle ring. Several external aeration pipes are vertically arranged, and the outer baffle ring is a hollow tube arranged horizontally. The shape of the outer baffle ring is the same as the overall shape of the MBR aeration membrane assembly. The bottom ends of several external aeration pipes are uniformly fixedly connected to the top end of the outer baffle ring and communicate with it. The top ends of several external aeration pipes are all fixedly installed at the bottom end of the top plate and communicate with the air inlet pipe. The first group of MBR aeration membrane assemblies and the second group of MBR aeration membrane assemblies are counted from the outside inwards. The aeration membrane components are located on the outer and inner sides of the first aeration device, respectively, and the second set of MBR aeration membrane components, counting from the outside to the inside, vertically passes through the inner side of the outer baffle ring; the outer aeration pipe has several horizontally arranged first aeration holes, which are evenly and densely distributed along the length of the outer aeration pipe and the circumferential direction of its cross-section; the outer baffle ring has several second aeration holes, which are evenly and densely distributed along the circumference of the outer baffle ring and the circumferential direction of its cross-section; the outer baffle ring is located above the bottom plate.

[0011] Furthermore, the second aeration device includes: a central aeration pipe and a central baffle ring. Several central aeration pipes are vertically arranged, and the central baffle ring is a hollow tube arranged horizontally. The shape of the central baffle ring is the same as the overall shape of the MBR aeration membrane assembly. The bottom ends of several central aeration pipes are uniformly fixedly connected to the top end of the central baffle ring and communicate with it. The top ends of several central aeration pipes are all fixedly installed at the bottom end of the top plate and communicate with the air inlet pipe. The second and third sets of MBR aeration membrane assemblies, counted from the outside inwards, are located on the outer and inner sides of the second aeration device, respectively. The third set of MBR aeration membrane assemblies, counted from the outside inwards, is located from... The aeration pipe extends vertically downwards through the inner sides of the middle and outer baffle rings; several horizontally arranged first aeration holes are provided on the middle aeration pipe, and these first aeration holes are evenly and densely distributed along the length of the middle aeration pipe and the circumference of its cross-section; several middle aeration pipes are located inside several outer aeration pipes and are staggered from the outer aeration pipes in the circumferential direction; several second aeration holes are provided on the middle baffle ring, and these second aeration holes are evenly and densely distributed along the circumference of the middle baffle ring and the circumference of its cross-section; the middle baffle ring is located above the outer baffle ring, and several outer aeration pipes are located outside the middle baffle ring; the size of the outer baffle ring is larger than the size of the middle baffle ring.

[0012] Furthermore, the third aeration device includes: internal aeration pipes and internal baffles. Several internal aeration pipes are vertically arranged, and the internal baffles are hollow tubes arranged horizontally. The shape of the internal baffles is the same as the overall shape of the MBR aeration membrane assembly. The bottom ends of several internal aeration pipes are uniformly fixedly connected to the top end of the internal baffles and communicate with them. The top ends of several internal aeration pipes are all fixedly installed at the bottom end of the top plate and communicate with the air inlet pipe. The third and fourth MBR aeration membrane assemblies, counting from the outside in, are located on the outer and inner sides of the third aeration device, respectively. The fourth MBR aeration membrane assembly, counting from the outside in, vertically passes through the inner side of the internal baffles and the inner side of the middle baffles from top to bottom. The inner aeration pipe has several horizontally arranged first aeration holes, which are evenly distributed along the length of the inner aeration pipe and the circumference of its cross-section. Several inner aeration pipes are located inside several intermediate aeration pipes and are staggered circumferentially from the intermediate aeration pipes, and are oriented in the same direction as the outer aeration pipes. The inner baffle ring has several second aeration holes, which are evenly distributed along the circumference of the inner baffle ring and the circumference of its cross-section. The inner baffle ring is located above the intermediate baffle ring, and several intermediate aeration pipes are located outside the inner baffle ring. The intermediate baffle ring is located outside the inner baffle ring, and its size is larger than that of the inner baffle ring.

[0013] Furthermore, the lower aeration gas includes: an aeration plate, a bottom connecting plate, and a side plate. The bottom connecting plate is horizontally arranged and fixedly connected to a fixed frame, and the bottom end of the bottom connecting plate contacts and engages with the bottom end of the oxidation ditch. The aeration plate is inclinedly arranged above the bottom connecting plate, and the aeration plate is inclined upward along the fluid flow direction. The aeration plate, the bottom connecting plate, and the side plate form a hollow, sealed cavity connected to an air source located at the bottom of the oxidation ditch. The aeration plate includes: an inclined plate, a sill, an aeration trough, and lower aeration holes. Several sills and several aeration troughs are respectively provided on the top surface of the inclined plate. The sills protrude from the top surface of the inclined plate, and the aeration troughs are recessed in the top surface of the inclined plate. Several sills and several aeration troughs are connected end to end in sequence. The aeration trough is a concave arc shape, and several radially arranged lower aeration holes are densely distributed on the arc surface. The air ejected through the lower aeration holes can wash the lower part of the corresponding MBR aeration membrane module.

[0014] Furthermore, the distance between the two ends of the sloping ramp perpendicular to the fluid flow direction is equal to the width of the inclined plate, and the distance between the two ends of the aeration tank perpendicular to the fluid flow direction is equal to the width of the inclined plate.

[0015] An MBR wastewater treatment method, using the above-mentioned MBR wastewater treatment device, wherein the wastewater treatment method is specifically as follows: Prepare several MBR wastewater treatment units according to process requirements; Several MBR wastewater treatment units were hoisted into the bottom of the oxidation ditch, in front of the flow generator, using a crane. The gas source is connected to the aeration gas, the first aeration device, the second aeration device and the third aeration device respectively, and the flow rate is controlled by the regulating valve; Open the air source regulating valve and start the flow generator. Compressed air with a certain pressure enters the lower aeration gas, the first aeration device, the second aeration device, and the third aeration device respectively. It aerates the fluid in the oxidation ditch and flushes the four sets of MBR aeration membrane modules by opening the air source regulating valve and starting the flow generator.

[0016] Compared with the prior art, the beneficial effects of the present invention are: The MBR wastewater treatment device and method provided in this invention, in a non-discharge state, involves placing a number of MBR wastewater treatment devices in an oxidation ditch. The forces generated by the fluid and aeration cause deformation of the MBR aeration membrane modules. Simultaneously, a base plate drives all MBR aeration membrane modules to swing at a certain angle, causing the MBR aeration membrane modules to be subjected to multi-directional and multi-layered forces at different heights, resulting in multi-directional deformation. This effectively reduces impurities adsorbed on the membrane surface, reduces membrane fouling, increases the utilization efficiency of the MBR aeration membrane modules, reduces backwashing intervals, and effectively improves the process effect of deep treatment. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the device structure according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the gas aeration structure in an embodiment of the present invention; Figure 3 This is a schematic diagram of the circular base plate (top plate) structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the rectangular base plate (top plate) structure according to an embodiment of the present invention; Figure 5 This is a schematic diagram showing the positions of each retaining ring in an embodiment of the present invention; Figure 6 This is a schematic diagram of the device structure in Embodiment 2 of the present invention.

[0018] The labels in the attached diagram are as follows: 1-Top plate, 2-Bottom plate, 21-Body body, 22-Mounting body, 3-External aeration pipe, 4-Middle aeration pipe, 5-Inner aeration pipe, 6-Outer retaining ring, 60-Limit ring one, 7-Middle retaining ring, 70-Limit ring two, 8-Inner retaining ring, 80-Limit ring three, 9-First fixing chain, 10-Fixing frame, 11-MBR aeration membrane assembly, 12-Lower aeration gas, 121-Inclined plate, 122-Shore, 123-Aeration trough, 124-Lower aeration hole, 13-Second fixing chain, 14-Inlet pipe, 15-Outlet pipe, α-Bottom plate setting swing angle, β-Angle between inclined plate and horizontal plane, A-Shortest distance between limit ring one and outer retaining ring, B-Shortest distance between limit ring two and middle retaining ring, C-Shortest distance between limit ring three and inner retaining ring. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0020] Example 1 like Figure 1As shown, an MBR wastewater treatment device is installed at the bottom of an oxidation ditch in front of a flow booster. It includes: a top plate 1, a bottom plate 2, a first aeration device, a second aeration device, a third aeration device, a first fixing chain 9, a fixing frame 10, an MBR aeration membrane assembly 11, a lower aeration gas 12, and a second fixing chain 13. The top plate 1 is fixedly installed on the top of the fixing frame 10, and the fixing frame 10 is supported at the bottom of the oxidation ditch. The bottom plate 2 is connected to the bottom of the top plate 1 through the first fixing chain 9. The MBR aeration membrane assembly 11 is provided in four sets, which are arranged between the top plate (1) and the bottom plate (2), and are respectively arranged from the outside to the inside as follows: the outer side of the first aeration device, the area between the first and second aeration devices, the area between the second and third aeration devices, and the inner side of the third aeration device. The lower aeration gas 12 is located at the bottom of the oxidation ditch and is fixedly connected to the fixing frame 10. The top of the lower aeration gas 12 is connected to the bottom of the bottom plate 2 through the second fixing chain 13.

[0021] Both the first fixed chain 9 and the second fixed chain 13 are flexible bodies; the number of the first fixed chains 9 is 3 to 6, and the number of the second fixed chains 13 is 1 to 4. The top and bottom ends of the first fixed chains 9 are respectively fixedly connected to the bottom end of the top plate 1 and the top end of the bottom plate 2; the top and bottom ends of the second fixed chains 13 are respectively fixedly connected to the bottom end of the bottom plate 2 and the top end of the lower aeration gas 12.

[0022] When the base plate 2 or the MBR aeration membrane module 11 is subjected to a force in a certain direction, the overall structure formed by the base plate 2 and the MBR aeration membrane module 11 swings at a certain angle. The upper fixed point is the upper end of the first fixed chain 9, and the lower fixed point is the lower end of the second fixed chain 13. The base plate 2 and the MBR aeration membrane module 11 are constrained by the first fixed chain 9 and the second fixed chain 13. By adjusting the length and number of the first fixed chain 9 and the second fixed chain 13, the swing angle α of the base plate 2 and the MBR aeration membrane module 11 can be set, where α = 1 to 6°.

[0023] like Figures 3-4 As shown, the bottom plate 2 and the top plate 1 have the same shape and each includes: a body 21 and a mounting body 22. Several mounting bodies 22 are provided and are set on the body 21. Four sets of MBR aeration membrane modules 11 are respectively installed between the top plate 1 and the bottom plate 2 through several mounting bodies 22. The MBR aeration membrane module 11 is a curtain membrane and the overall cross-section is circular or U-shaped. Two adjacent sets of MBR aeration membrane modules 11 are spaced apart.

[0024] The top plate 1 is equipped with an air inlet pipe connected to the air source, and the air inlet pipe is also connected to the first aeration device, the second aeration device and the third aeration device respectively; the lower aeration gas 12 is connected to the air source.

[0025] The first aeration device includes: external aeration pipes 3 and external baffle rings 6. Four to eight external aeration pipes 3 are vertically arranged. The external baffle rings 6 are hollow tubes and horizontally arranged. The shape of the external baffle rings 6 is the same as the overall shape of the MBR aeration membrane assembly 11. The bottom ends of several external aeration pipes 3 are evenly and fixedly connected to the top end of the external baffle rings 6 and communicate with them. The top ends of several external aeration pipes 3 are all fixedly installed at the bottom end of the top plate 1 and communicate with the air inlet pipe. The first group of MBR aeration membrane assemblies 11 and the second group of MBR aeration membrane assemblies 11, counted from the outside in, are respectively located in the first aeration... The second set of MBR aeration membrane modules 11, counting from the outside to the inside, vertically passes through the inner side of the outer baffle ring 6 on the outer side and the inner side of the aeration device; several horizontally arranged first aeration holes are opened on the outer aeration pipe 3, and the several first aeration holes are evenly and densely distributed along the length direction of the outer aeration pipe 3 and the circumferential direction of its cross-sectional circle; several second aeration holes are opened on the outer baffle ring 6, and the several second aeration holes are evenly and densely distributed along the circumferential direction of the outer baffle ring 6 and the circumferential direction of its cross-sectional circle; the diameter of the first aeration holes and the second aeration holes is 0.08~0.3mm; the outer baffle ring 6 is located above the bottom plate 2.

[0026] The second aeration device includes: a central aeration pipe 4 and a central baffle ring 7. Four to eight central aeration pipes 4 are vertically arranged. The central baffle ring 7 is a hollow tube and horizontally arranged. The shape of the central baffle ring 7 is the same as the overall shape of the MBR aeration membrane assembly 11. The bottom ends of several central aeration pipes 4 are evenly and fixedly connected to the top end of the central baffle ring 7 and communicate with it. The top ends of several central aeration pipes 4 are all fixedly installed at the bottom end of the top plate 1 and communicate with the air inlet pipe. The second and third sets of MBR aeration membrane assemblies 11, counted from the outside inwards, are located on the outer and inner sides of the second aeration device, respectively. The third set of MBR aeration membrane assemblies 11, counted from the outside inwards, vertically passes through the inner side of the central baffle ring 7 from top to bottom. The outer baffle ring 6 is located inside the middle aeration pipe 4, which has several horizontally arranged first aeration holes. These first aeration holes are evenly and densely distributed along the length of the middle aeration pipe 4 and the circumference of its cross-section. The middle aeration pipe 4 is located inside the middle aeration pipe 3 and is staggered from the middle aeration pipe 3 in the circumferential direction. The middle baffle ring 7 has several second aeration holes. These second aeration holes are evenly and densely distributed along the circumference of the middle baffle ring 7 and the circumference of its cross-section. The diameter of the first and second aeration holes is 0.08 to 0.3 mm. The middle baffle ring 7 is located above the outer baffle ring 6, and the middle aeration pipe 3 is located outside the middle baffle ring 7. The size of the outer baffle ring 6 is larger than the size of the middle baffle ring 7.

[0027] The third aeration device includes: internal aeration pipes 5 and internal baffles 8. Four to eight internal aeration pipes 5 are vertically arranged. The internal baffles 8 are hollow tubes and horizontally arranged. The shape of the internal baffles 8 is the same as the overall shape of the MBR aeration membrane assembly 11. The bottom ends of several internal aeration pipes 5 are evenly and fixedly connected to the top end of the internal baffles 8 and communicate with the internal baffles 8. The top ends of several internal aeration pipes 5 are all fixedly installed at the bottom end of the top plate 1 and communicate with the air inlet pipe. The third and fourth sets of MBR aeration membrane assemblies 11, counting from the outside in, are located on the outer and inner sides of the third aeration device, respectively. The fourth set of MBR aeration membrane assemblies 11, counting from the outside in, vertically passes through the inner side of the internal baffles 8, the inner side of the middle baffles 7, and the inner side of the outer baffles 6 from top to bottom. The air pipe 5 has several horizontally arranged first aeration holes, which are evenly and densely distributed along the length of the inner aeration pipe 5 and the circumference of its cross-section. The inner aeration pipes 5 are located inside the middle aeration pipes 4 and are staggered in the circumferential direction from the middle aeration pipes 4, and are in the same orientation as the outer aeration pipes 3. The inner baffle ring 8 has several second aeration holes, which are evenly and densely distributed along the circumference of the inner baffle ring 8 and the circumference of its cross-section. The diameter of the first and second aeration holes is 0.08 to 0.3 mm. The inner baffle ring 8 is located above the middle baffle ring 7 and the middle aeration pipes 4 are located outside the inner baffle ring 8. The middle baffle ring 7 is located outside the inner baffle ring 8, and the size of the middle baffle ring 7 is larger than the size of the inner baffle ring 8.

[0028] When compressed air is introduced into the first, second, and third aeration devices, the MBR aeration membrane module 11 is flushed from the following aspects to prevent sludge from depositing and adhering to the membrane surface: 1. Gas is horizontally and at high speed injected from the first aeration hole in each vertical aeration pipe in a circumferential direction, aerating the surrounding wastewater at different radii. Simultaneously, it washes the surface of the MBR aeration membrane module 11 inside and outside the aeration pipes at different heights, expanding the washing range of the MBR aeration membrane module 11 and causing it to deform at different heights and in different directions. Compared to traditional bottom aeration methods, this more effectively prevents sludge deposition and adhesion on the membrane surface, helps maintain membrane permeability, reduces membrane fouling, and extends membrane lifespan. The water flow disturbance generated by aeration breaks down the gel layer formed by sludge flocs on the membrane surface, making it less prone to pollutant accumulation, reducing membrane filtration resistance, and ensuring continuous and stable wastewater filtration and separation. Meanwhile, because several intermediate aeration pipes 4 are staggered with several external aeration pipes 3, and several internal aeration pipes 5 are staggered with several intermediate aeration pipes 4, the air sprayed from the first aeration hole on each aeration pipe is in different directions. As a result, the MBR aeration membrane module 11 deforms in different directions. Within a certain height and circumference range, the sprayed air and the MBR aeration membrane module 11 are mutually squeezed, collided and rebounded, which further enhances the shedding of pollutants on the MBR aeration membrane module 11.

[0029] 2. Gas is aerated and oxygenated in the wastewater from the outer baffle ring 6, middle baffle ring 7, and inner baffle ring 8, which are in a horizontal state, at different radii and circumferential directions. At the same time, the surface of the MBR aeration membrane module 11 inside and outside the baffle rings at different heights is washed. The air sprayed upward and downward in the circumferential direction further expands the washing range of the MBR aeration membrane module 11, causing the MBR aeration membrane module 11 to tilt and deform at different heights and in different circumferential directions, which is more conducive to preventing sludge deposition and adhesion on the membrane surface.

[0030] 3. The air jetted upwards and downwards at an angle in the circumferential direction by the horizontal outer baffle ring 6, middle baffle ring 7, and inner baffle ring 8 differs in direction from the air jetted horizontally by the vertical outer aeration pipe 3, middle aeration pipe 4, and inner aeration pipe 5. This causes the MBR aeration membrane module 11 to deform in different directions, further preventing sludge deposition and adhesion on the membrane surface. Simultaneously, when the two air jets meet, they collide and cut, making the bubbles smaller and denser, thus improving oxygen transfer efficiency.

[0031] 4. Air jets at different heights, radial directions, and circumferential directions act on the MBR aeration membrane module 11, causing it to deform. The deformed MBR aeration membrane module 11 drives the base plate, which in turn causes all the MBR aeration membrane modules 11 on it to swing at a certain angle, causing all or most of the MBR aeration membrane modules 11 to bend irregularly. This shakes off more impurities attached to the membrane surface, expanding the range of anti-deposition and anti-adhesion on the surface of the MBR aeration membrane module 11. This overcomes the limitation of existing technologies where fluids only cause local deformation of some membrane modules and have no effect on other membrane modules.

[0032] like Figure 5 As shown, the cross-sections of limit ring 1 60 and outer retaining ring 6 are coplanar and located outside the outer retaining ring 6; the cross-sections of limit ring 2 70 and middle retaining ring 7 are coplanar and located outside the middle retaining ring 7; and the cross-sections of limit ring 3 80 and inner retaining ring 8 are coplanar and located outside the inner retaining ring 8. Limit ring 1 60, limit ring 2 70, and limit ring 3 80 are all located on the conical generatrix set when the base plate 2 is at the limit position of the set swing angle. The shortest distance between limit ring 1 60 and outer retaining ring 6 is A, the shortest distance between limit ring 2 70 and middle retaining ring 7 is B, and the shortest distance between limit ring 3 80 and inner retaining ring 8 is C, and C > B > A. The purpose of setting the inner retaining ring 8, the middle retaining ring 7, and the outer retaining ring 6 is: 1. Because the middle baffle ring 7 is far from the conical generatrix of the swing angle set by the bottom plate 2, and the upper inner baffle ring 8 is even further away from the conical generatrix of the swing angle set by the bottom plate 2 than the middle baffle ring 7, when all MBR aeration membrane modules 11 swing in a certain direction along with the bottom plate 2 around the top plate 1, the inner wall of the inner baffle ring 8, which is stationary in the upper position, first touches the fourth group of MBR aeration membrane modules 11 moving outward on its inner side. The inner ring of the inner baffle ring 8 hinders the outward movement of the MBR aeration membrane modules 11 within the ring. Above and below this height, the MBR aeration membrane modules 11 continue to move outward due to inertia, causing the fourth group of MBR aeration membrane modules 11 to undergo a large-scale deformation above and below the upper inner baffle ring 8, resulting in irregular and large-scale bending of the MBR aeration membrane modules 11. This makes it easier to shake off impurities attached to the membrane surface, effectively preventing sludge deposition and adhesion on the membrane surface, and helping to maintain membrane permeability.

[0033] 2. As all MBR aeration membrane modules 11 continue to move in a certain direction, the inner baffle ring 8 continuously intensifies the bending deformation of the fourth group of MBR aeration membrane modules 11 on its inner side, continuously enhancing the effect of shaking off impurities attached to the membrane surface. When the outermost ring of the third group of MBR aeration membrane modules 11 between the middle baffle ring 7 in the middle position and the inner baffle ring 8 in the upper position touches the inner wall of the middle baffle ring 7, the stationary middle baffle ring 7 hinders the outward movement of this MBR aeration membrane module 11. Above and below this height, this MBR aeration membrane module 11 continues to move outward due to inertia, causing the middle baffle ring 7 in the middle of the MBR aeration membrane module 11 to deform significantly, resulting in irregular and significant bending of this MBR aeration membrane module 11, thereby intensifying the shaking off of impurities attached to this MBR aeration membrane module 11.

[0034] 3. All MBR aeration membrane modules 11 continue to move in a certain direction. The middle baffle ring 7 continuously intensifies the bending deformation of the adjacent third group of MBR aeration membrane modules 11 above and below the middle baffle ring 7, continuously enhancing the effect of shaking off impurities attached to the membrane surface. When the outermost ring of the second group of MBR aeration membrane modules 11 between the outer baffle ring 6 in the lower position and the middle baffle ring 7 in the middle position touches the inner wall of the outer baffle ring 6, the inner wall of the stationary outer baffle ring 6 hinders the outward movement of the MBR aeration membrane module 11. Above and below this height, the MBR aeration membrane module 11 continues to move due to inertia, causing the MBR aeration membrane module 11 to undergo a larger deformation again in the lower part, resulting in irregular and larger-amplitude bending of the MBR aeration membrane module 11, which further intensifies the shaking off of impurities attached to the membrane surface.

[0035] 4. Due to inertia, all MBR aeration membrane modules 11 continue to move in a certain direction until they reach the limit position of the set swing angle α on the bottom plate 2. The outer retaining ring 6 continuously intensifies the bending deformation of the adjacent MBR aeration membrane modules 11 on the inner side of the outer retaining ring 6, continuously enhancing the effect of shaking off impurities attached to the membrane surface, thus making it easier to shake off impurities attached to the membrane surface.

[0036] 5. The fourth MBR aeration membrane module 11 within the inner baffle ring 8 experiences varying degrees of deformation in the height direction due to the obstruction from the outer baffle ring 6, the middle baffle ring 7, and the inner baffle ring 8, with the deformation gradually increasing. Similarly, the third MBR aeration membrane module 11 between the inner baffle ring 8 and the middle baffle ring 7 also experiences varying degrees of deformation in the height direction due to the obstruction from the outer baffle ring 6 and the middle baffle ring 7, with the deformation gradually increasing. The second MBR aeration membrane module 11 between the middle baffle ring 7 and the outer baffle ring 6 is deformed due to the obstruction from the outer baffle ring 6. These MBR aeration membrane modules 11, exhibiting different deformation amounts at different heights and radii, interact with each other, thereby enhancing the shedding of impurities adhering to the membrane surface.

[0037] like Figure 2 As shown, the lower aeration gas 12 includes: an aeration plate, a bottom connecting plate, and a side plate. The bottom connecting plate is horizontally arranged and fixedly connected to the fixing frame 10, and the bottom end of the bottom connecting plate is in contact with the bottom end of the oxidation ditch. The aeration plate is inclinedly arranged above the bottom connecting plate, and the aeration plate is inclined upward along the fluid flow direction. The angle between the aeration plate and the horizontal plane is β; β = 3~12°. The aeration plate, the bottom connecting plate, and the side plate form a hollow closed cavity connected to the air source arranged at the bottom of the oxidation ditch. The aeration plate includes: an inclined plate 121, a sill 122, an aeration trough 123, and a lower aeration hole 124. Several sills 122 and several aeration holes are respectively provided on the top surface of the inclined plate 121. The trough 123 and the sill 122 protrude from the top surface of the inclined plate 121, while the aeration trough 123 is recessed from the top surface of the inclined plate 121. Several sills 122 and several aeration troughs 123 are connected end to end in sequence, from the back to the front of the water flow, namely the first sill, the first aeration trough, the second sill, the second aeration trough, and so on. The length of the aeration trough along the inclined plane is 4 to 10 times the length of the sill. The aeration trough 123 is a concave arc shape with several radially arranged lower aeration holes 124 densely distributed on the arc surface. The diameter of the lower aeration holes 124 is 0.1 to 0.5 mm. The air ejected through the lower aeration holes 124 can wash the lower part of the corresponding MBR aeration membrane module 11.

[0038] The axis of the lower aeration hole 124 gradually changes from inclined upward and forward to inclined upward and backward along the fluid flow direction. This arrangement facilitates the application of forces in different directions to the lower parts of the MBR aeration membrane modules 11 along different lengths. The air jets from the front and rear of the aeration channel 124 act on different MBR aeration membrane modules 11, forming opposite axial components. This causes the MBR aeration membrane modules 11 to deform in opposite directions, facilitating the removal of impurities adhering to the membrane surface and reducing fouling. Furthermore, the collision and compression between adjacent MBR aeration membrane modules 11 further dislodges impurities from the membrane. Simultaneously, the force generated by the air acting on the lower part of the MBR aeration membrane module 11 drives the base plate 2, which in turn causes the entire MBR aeration membrane module 11 to swing around a fixed point, further accelerating the removal of impurities from the membrane surface and thus expanding the anti-deposition and anti-adhesion range on the surface of the MBR aeration membrane module 11. That is, the MBR aeration membrane module 11 with a small amount of force drives all the MBR aeration membrane modules 11 to move, causing more MBR aeration membrane modules 11 to deform and achieve the removal of more impurities on the membrane surface.

[0039] The middle and upper parts of the vertically arranged MBR aeration membrane module 11 deform forward under the action of the main fluid. The deformation in different directions accelerates the removal of impurities from the MBR aeration membrane module 11, effectively improving the operating conditions of the MBR aeration membrane module 11. This overcomes the limitation of existing technologies that rely solely on the main fluid to generate unidirectional deformation.

[0040] The distance between the two ends of the sill 122 perpendicular to the fluid flow direction is equal to the width of the inclined plate 121, and the distance between the two ends of the aeration tank 123 perpendicular to the fluid flow direction is equal to the width of the inclined plate 121. The sill 122 can be a constant cross-section or a variable cross-section along the width direction of the inclined plate 121.

[0041] When the constant cross-section sill 122 is selected, when the main fluid moves to the first sill on the inclined plate 121, the fluid with a certain velocity will jump for the first time in the entire width direction, impacting the lower part of the aeration membrane module 11 and a part of the base plate 2, causing the already deformed MBR aeration membrane module 11 to be impacted again. Due to its large lever arm, the deformed MBR aeration membrane module 11 drives the base plate 2, and the stressed base plate 2 (including the force of the fluid on the base plate) in turn causes all MBR aeration membrane modules 11 to repeatedly swing around the upper and lower fixed points. When the main fluid moves to the second, third, and so on, it will jump in the length direction in turn, continuously driving the base plate 2 and the MBR aeration membrane module 11 to swing. The successive obstruction of the inner baffle ring 8, the middle baffle ring 7, and the outer baffle ring 6 at different heights will cause more impurities on the MBR aeration membrane module 11 to fall off, further reducing the fouling phenomenon of the MBR aeration membrane module 11.

[0042] When a variable cross-section sill 122 is selected, the first sill gradually decreases or increases along the width direction of the inclined plate 121, while the second sill gradually increases or decreases along the width direction of the inclined plate 121, the third sill gradually decreases or increases along the width direction of the inclined plate 121, and so on, with sills 122 of different variation patterns alternately arranged along the length direction. When the main fluid moves to the first sill on the inclined plate 121, the fluid with a certain velocity makes its first jump in the entire width direction, impacting the lower part of the MBR aeration membrane module 11 and a local part of the base plate 2, causing the already deformed MBR aeration membrane module 11 to be impacted again. The magnitude and direction of the force acting on the MBR aeration membrane module 11 in the width direction have changed. In addition to the original oscillation in the length direction, a certain circumferential oscillation is also generated in the width direction. The MBR aeration membrane module 11 under force drives the base plate 2 (including the force of the fluid on the base plate), and the base plate 2 in turn drives all the MBR aeration membrane modules 11 to oscillate in multiple directions, which improves the overall repeated oscillation effect of the MBR aeration membrane module 11. The successive obstruction of the inner baffle ring 8, the middle baffle ring 7 and the outer baffle ring 6 causes more impurities on the MBR aeration membrane module 11 to fall off at different heights, further reducing the pollution phenomenon of the MBR aeration membrane module 11. When the main fluid reaches the second sill, the magnitude and direction of the force acting on the MBR aeration membrane module 11 in the width direction change again. Based on the original oscillation in the length direction, a certain reverse circumferential oscillation occurs in the width direction, further enhancing the shedding of impurities from the MBR aeration membrane module 11. When the main fluid reaches the third sill… and so on, it successively jumps in the length direction, generating forces of different magnitudes and directions, continuously driving the base plate 2 and the MBR aeration membrane module 11 to form alternating oscillations. Meanwhile, the inner baffle ring 8, middle baffle ring 7, and outer baffle ring 6 successively obstruct the flow, causing more impurities to detach from the MBR aeration membrane module 11 at different heights, further mitigating the fouling phenomenon of the MBR aeration membrane module 11, accelerating the rinsing effect of the MBR aeration membrane module 11, and ensuring the efficient operation of the MBR aeration membrane module 11.

[0043] Example 2 like Figure 6 As shown, an MBR wastewater treatment device is installed in the integrated wastewater treatment equipment. An inlet pipe 14 is installed behind the MBR wastewater treatment device. The inlet pipe 14 is located between the lower aeration gas 12 and the bottom plate 2 and is laid along the width of the pool. Its length is equal to the width of the MBR aeration membrane module 11. The outlet pipe 15 is installed on the upper part of the front pool wall.

[0044] The inlet pipe 14 has several outlets on its front wall facing the MBR aeration membrane module 11. These outlets are evenly distributed along the width direction, with their axes horizontally positioned. A fluid with a certain pressure is ejected at high speed from the outlets and flows rapidly over the aeration plate of the lower aeration gas 12. The fluid jumps sequentially on several sills 124, continuously generating forces of varying magnitudes and directions on the bottom plate 2 and the MBR aeration membrane module 11. Based on the original oscillation along its length, the force-bearing MBR aeration membrane module 11 drives the bottom plate 2, which in turn drives the oscillation of all the MBR aeration membrane modules 11, also producing a certain circumferential oscillation along its width, thus forming an alternating oscillation. The successive obstruction of the inner baffle ring 8, middle baffle ring 7, and outer baffle ring 6 at different heights causes more impurities to fall off the MBR aeration membrane module 11, further intensifying the oscillation phenomenon and accelerating the flushing effect of the MBR aeration membrane module 11, ensuring its efficient operation.

[0045] Gas is horizontally and at high speed from the first aeration holes of the vertically positioned external aeration pipe 3, middle aeration pipe 4, and inner aeration pipe 5, aerating the surrounding wastewater at different radii. Simultaneously, it scours the surface of the MBR aeration membrane module 11 inside and outside the aeration pipes at different heights, expanding the scouring range and causing deformation of the MBR aeration membrane module 11 at different heights and directions. At the same time, because several middle aeration pipes 4 are staggered with several external aeration pipes 3, and several inner aeration pipes 5 are staggered with several middle aeration pipes 4, the air ejected from the first aeration holes on each aeration pipe is at different directions. Therefore, the MBR aeration membrane module 11 deforms in different directions. Within a certain height range, the ejected air and the MBR aeration membrane module 11 interact through mutual compression, collision, and rebound, further enhancing the shedding of pollutants from the MBR aeration membrane module 11.

[0046] An MBR wastewater treatment method, the specific details of which are as follows: Prepare several MBR wastewater treatment units according to process requirements; Several MBR wastewater treatment units were hoisted into the bottom of the oxidation ditch, in front of the flow generator, using a crane. The gas source is connected to the lower aeration gas 12, the first aeration device, the second aeration device and the third aeration device respectively, and the flow rate is controlled by the regulating valve; Open the air source regulating valve and start the flow generator. Compressed air with a certain pressure enters the lower aeration gas 12, the first aeration device, the second aeration device and the third aeration device respectively. It aerates the fluid in the oxidation ditch and flushes the four sets of MBR aeration membrane modules 11 by opening the air source regulating valve and starting the flow generator.

[0047] 1. Gas is horizontally and at high speed injected from the first aeration hole of each vertical aeration pipe in a circumferential direction, aerating and oxygenating the surrounding wastewater at different radii. Simultaneously, it washes the surface of the MBR aeration membrane module 11 inside and outside the aeration pipes at different heights, expanding the washing range of the MBR aeration membrane module 11 and causing it to deform at different heights and in different directions, effectively preventing sludge deposition and adhesion on the membrane surface.

[0048] 2. Because several intermediate aeration pipes 4 are staggered with several external aeration pipes 3, and several internal aeration pipes 5 are staggered with several intermediate aeration pipes 4, the air ejected from the first aeration hole on each aeration pipe is in different directions. As a result, the MBR aeration membrane module 11 deforms in different directions. Within a certain height range, the ejected air and the MBR aeration membrane module 11 are mutually squeezed, collided and rebounded, which further enhances the shedding of pollutants on the MBR aeration membrane module 11.

[0049] 3. Gas is aerated and oxygenated in the circumferential direction by the outer baffle ring 6, middle baffle ring 7 and inner baffle ring 8 in a horizontal state at different radii and circumferential directions. At the same time, the surface of the MBR aeration membrane module 11 inside and outside the baffle rings at different heights is washed. The air sprayed upward and downward in the circumferential direction expands the washing range of the MBR aeration membrane module 11, causing the MBR aeration membrane module 11 to tilt and deform, which is more conducive to preventing sludge from depositing and adhering on the membrane surface.

[0050] 4. The air jets from each baffle ring and aeration pipe are directed in different directions, causing the MBR aeration membrane module 11 to deform in different directions, further preventing sludge deposition and adhesion on the membrane surface. Simultaneously, when two air jets meet, they collide and cut each other, improving oxygen transfer efficiency.

[0051] 5. Air jets at different heights, radial directions, and circumferential directions act on the MBR aeration membrane module 11, causing the MBR aeration membrane module 11 to deform. The deformed MBR aeration membrane module 11 drives the base plate 2, which in turn causes all the MBR aeration membrane modules 11 on it to swing at a certain angle, thereby causing all or most of the MBR aeration membrane modules 11 to bend irregularly, expanding the anti-deposition and adhesion range on the surface of the MBR aeration membrane module 11.

[0052] 6. When all MBR aeration membrane modules 11 swing in a certain direction along with the bottom plate 2 around the top plate 1, the inner retaining ring 8 first hinders the outward movement of the MBR aeration membrane modules 11 within its ring. A large deformation occurs above and below this height, making it easier to shake off the impurities attached to the membrane surface and effectively preventing the deposition and adhesion of sludge on the membrane surface.

[0053] 7. All MBR aeration membrane modules 11 continue to move in a certain direction. The inner retaining ring 8 continuously intensifies the bending deformation of the MBR aeration membrane module 11 on its inner side, continuously enhancing the effect of shaking off impurities attached to the membrane surface. When the outermost ring of the MBR aeration membrane module 11 adjacent to the inner side of the middle retaining ring 7 touches the inner wall of the middle retaining ring 7, the middle retaining ring 7 hinders the outward movement of this MBR aeration membrane module 11, and irregular and large-amplitude bending also occurs above and below this height, thereby intensifying the shaking off of impurities attached to the membrane surface.

[0054] 8. All MBR aeration membrane modules 11 continue to move in a certain direction. The middle baffle ring 7 continuously intensifies the bending deformation of the adjacent MBR aeration membrane modules 11 above and below the middle baffle ring 7, continuously enhancing the effect of shaking off impurities attached to the membrane surface. When the outermost ring of the MBR aeration membrane module 11 adjacent to the inner side of the outer baffle ring 6 touches the inner wall of the outer baffle ring 6, the outer baffle ring 6 hinders the outward movement of the MBR aeration membrane module 11. Above and below this height, the MBR aeration membrane module 11 undergoes a larger deformation, thereby further intensifying the shaking off of impurities attached to the membrane surface.

[0055] 9. Due to inertia, all MBR aeration membrane modules 11 continue to move in a certain direction until they reach the bottom plate 2 at the limit position of the set swing angle α. The outer retaining ring 6 continuously aggravates the bending deformation and impurity shaking effect of the MBR aeration membrane module 11 above and below the outer retaining ring 6.

[0056] 10. The MBR aeration membrane modules 11, which exhibit different deformations at different heights and radii, interact with each other, thereby enhancing the shedding of impurities attached to the membrane surface.

[0057] 11. The air jets from the front and rear of the aeration tank 124 act on different MBR aeration membrane modules 11, causing the MBR aeration membrane modules 11 to deform in opposite directions, shaking off impurities attached to the membrane surface. Adjacent MBR aeration membrane modules 11 collide and compress with each other, further dislodging impurities from the membrane. Simultaneously, the force generated by the air acting on the lower part of the MBR aeration membrane modules 11 drives the base plate 2 (including the force exerted by the fluid on the base plate), which in turn causes all the MBR aeration membrane modules 11 to oscillate around a fixed point, further accelerating the detachment of more membrane surface impurities.

[0058] 12. The middle and upper parts of the vertically arranged MBR aeration membrane module 11 deform forward under the action of the main fluid. The deformation in different directions accelerates the shedding of impurities on the MBR aeration membrane module 11.

[0059] 13. As the fluid moves to the first ledge, the second ledge, and so on, it successively jumps along its length, impacting the lower part of the MBR aeration membrane module 11. This causes the already deformed MBR aeration membrane module 11 to be impacted again, resulting in repeated oscillations in the width direction in addition to the original oscillations along its length. The stressed MBR aeration membrane module 11 drives the base plate 2 (including the force exerted by the fluid on the base plate), which in turn causes all the MBR aeration membrane modules 11 to oscillate. The successive obstructive effects of the inner baffle ring 8, the middle baffle ring 7, and the outer baffle ring 6, at different heights, progressively exacerbate the shedding of impurities from the MBR aeration membrane module 11, further mitigating the fouling phenomenon of the MBR aeration membrane module 11.

[0060] In the description of this invention, it should be noted that the terms "upper", "lower", "left", "right", "inner", "outer", "top / bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the technical solution of the present invention, based on the technical essence of the present invention, shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. An MBR wastewater treatment device, disposed at the bottom of an oxidation ditch located in front of a flow promoter, characterized in that, include: The structure includes a top plate (1), a bottom plate (2), a first aeration device, a second aeration device, a third aeration device, a first fixing chain (9), a fixing frame (10), an MBR aeration membrane assembly (11), a lower aeration gas (12), and a second fixing chain (13). The top plate (1) is fixedly installed on the top of the fixing frame (10), which is supported at the bottom of the oxidation ditch. The bottom plate (2) is connected to the bottom of the top plate (1) via the first fixing chain (9). The MBR aeration membrane assembly (11) consists of four sets, which are arranged between the top plate (1) and the bottom plate (2), and are respectively arranged from the outside to the inside of the outer side of the first aeration device, between the first and second aeration devices, between the second and third aeration devices, and inside the third aeration device. The lower aeration gas (12) is located at the bottom of the oxidation ditch and is fixedly connected to the fixing frame (10). The top of the lower aeration gas (12) is connected to the bottom of the bottom plate (2) via the second fixing chain (13).

2. The MBR wastewater treatment device according to claim 1, characterized in that: Both the first fixed chain (9) and the second fixed chain (13) are flexible bodies. The top and bottom ends of the first fixed chain (9) are fixedly connected to the bottom end of the top plate (1) and the top end of the bottom plate (2), respectively. The top and bottom ends of the second fixed chain (13) are fixedly connected to the bottom end of the bottom plate (2) and the top end of the lower aeration gas (12), respectively.

3. The MBR wastewater treatment device according to claim 2, characterized in that: The bottom plate (2) and the top plate (1) have the same shape and each includes a body (21) and an mounting body (22). There are several mounting bodies (22). The mounting bodies (22) are set on the body (21). The four sets of MBR aeration membrane modules (11) are installed between the top plate (1) and the bottom plate (2) through several mounting bodies (22). The MBR aeration membrane module (11) is a curtain membrane, and the overall cross-section is circular or U-shaped. The two adjacent sets of MBR aeration membrane modules (11) are spaced apart.

4. The MBR wastewater treatment device according to claim 3, characterized in that: The top plate (1) is provided with an air inlet pipe connected to the air source, and the air inlet pipe is also connected to the first aeration device, the second aeration device and the third aeration device respectively; the lower aeration gas (12) is connected to the air source.

5. The MBR wastewater treatment device according to claim 4, characterized in that: The first aeration device includes: external aeration pipes (3) and an outer baffle ring (6). Several external aeration pipes (3) are vertically arranged. The outer baffle ring (6) is a hollow tube and is horizontally arranged. The shape of the outer baffle ring (6) is the same as the overall shape of the MBR aeration membrane assembly (11). The bottom ends of several external aeration pipes (3) are uniformly fixedly connected to the top end of the outer baffle ring (6) and connected to the outer baffle ring (6). The top ends of several external aeration pipes (3) are all fixedly installed at the bottom end of the top plate (1) and connected to the air inlet pipe. The first group of MBR aeration membrane assemblies (11) and the second group of MBR aeration membrane assemblies (11) are arranged from the outside to the inside. The BR aeration membrane assembly (11) is located on the outside and inside of the first aeration device, respectively, and the second group of MBR aeration membrane assemblies (11) counted from the outside to the inside vertically passes through the inside of the outer baffle (6); the outer aeration pipe (3) is provided with a number of horizontally arranged first aeration holes, and the number of first aeration holes are evenly and densely distributed along the length direction of the outer aeration pipe (3) and the circumferential direction of its cross-section circle; the outer baffle (6) is provided with a number of second aeration holes, and the number of second aeration holes are evenly and densely distributed along the circumferential direction of the outer baffle (6) and the circumferential direction of its cross-section circle; the outer baffle (6) is located above the bottom plate (2).

6. The MBR wastewater treatment device according to claim 5, characterized in that: The second aeration device includes: a central aeration pipe (4) and a central baffle ring (7). Several central aeration pipes (4) are vertically arranged. The central baffle ring (7) is a hollow tube and is horizontally arranged. The shape of the central baffle ring (7) is the same as the overall shape of the MBR aeration membrane assembly (11). The bottom ends of several central aeration pipes (4) are uniformly fixedly connected to the top end of the central baffle ring (7) and are connected to the central baffle ring (7). The top ends of several central aeration pipes (4) are all fixedly installed at the bottom end of the top plate (1) and are connected to the air inlet pipe. The second group of MBR aeration membrane assemblies (11) and the third group of MBR aeration membrane assemblies (11) are located on the outside and inside of the second aeration device, respectively, and the third group of MBR aeration membrane assemblies (11) is located from the top to the inside. The middle aeration pipe (4) is vertically inserted through the inner side of the middle baffle (7) and the inner side of the outer baffle (6); the middle aeration pipe (4) is provided with several horizontally arranged first aeration holes, which are evenly and densely distributed along the length direction of the middle aeration pipe (4) and the circumferential direction of its cross-section circle; the middle aeration pipe (4) is located inside the middle aeration pipe (3) and is staggered from the middle aeration pipe (3) in the circumferential direction; the middle baffle (7) is provided with several second aeration holes, which are evenly and densely distributed along the circumferential direction of the middle baffle (7) and the circumferential direction of its cross-section circle; the middle baffle (7) is located above the outer baffle (6) and the middle aeration pipe (3) is located outside the middle baffle (7); the size of the outer baffle (6) is larger than the size of the middle baffle (7).

7. The MBR wastewater treatment device according to claim 6, characterized in that: The third aeration device includes: an inner aeration pipe (5) and an inner baffle ring (8). Several inner aeration pipes (5) are vertically arranged. The inner baffle ring (8) is a hollow tube and is horizontally arranged. The shape of the inner baffle ring (8) is the same as the overall shape of the MBR aeration membrane assembly (11). The bottom ends of several inner aeration pipes (5) are uniformly fixedly connected to the top end of the inner baffle ring (8) and communicate with the inner baffle ring (8). The top ends of several inner aeration pipes (5) are all fixedly installed at the bottom end of the top plate (1) and communicate with the air inlet pipe. The third group of MBR aeration membrane assemblies (11) and the fourth group of MBR aeration membrane assemblies (11) are located on the outside and inside of the third aeration device, respectively, and the fourth group of MBR aeration membrane assemblies (11) passes vertically from top to bottom through the inner side of the inner baffle ring (8), the inner side of the middle baffle ring (7), and the inner side of the middle baffle ring (7). The inner side of the outer baffle ring (6); the inner aeration pipe (5) is provided with a number of horizontally arranged first aeration holes, which are evenly and densely distributed along the length direction of the inner aeration pipe (5) and the circumferential direction of its cross-section circle; the inner aeration pipe (5) is located inside the inner aeration pipe (4) and is arranged in a staggered manner with the inner aeration pipe (4) in the circumferential direction, and is in the same position as the outer aeration pipe (3); the inner baffle ring (8) is provided with a number of second aeration holes, which are evenly and densely distributed along the circumferential direction of the inner baffle ring (8) and the circumferential direction of its cross-section circle; the inner baffle ring (8) is located above the middle baffle ring (7) and the middle aeration pipe (4) is located outside the inner baffle ring (8); the middle baffle ring (7) is located outside the inner baffle ring (8), and the size of the middle baffle ring (7) is larger than the size of the inner baffle ring (8).

8. The MBR wastewater treatment device according to claim 7, characterized in that: The lower aeration gas (12) includes: an aeration plate, a bottom connecting plate, and a side plate. The bottom connecting plate is horizontally arranged and fixedly connected to the fixing frame (10). The bottom end of the bottom connecting plate is in contact with the bottom end of the oxidation ditch. The aeration plate is inclined above the bottom connecting plate. The aeration plate is inclined upward along the fluid flow direction. The aeration plate, the bottom connecting plate, and the side plate form a hollow closed cavity connected to the gas source located at the bottom of the oxidation ditch. The aeration plate includes: an inclined plate (121), a sill (122), an aeration trough (123), and a lower aeration hole (124). The top surface of the plate (121) is provided with several sills (122) and several aeration grooves (123). The sills (122) protrude from the top surface of the inclined plate (121), and the aeration grooves (123) are recessed in the top surface of the inclined plate (121). The sills (122) and the aeration grooves (123) are connected end to end in sequence. The aeration grooves (123) are concave arc-shaped and have several radially arranged lower aeration holes (124) densely distributed on the arc surface. The air ejected through the lower aeration holes (124) can wash the lower part of the corresponding MBR aeration membrane module (11).

9. The MBR wastewater treatment device according to claim 8, characterized in that: The distance between the two ends of the sill (122) perpendicular to the fluid flow direction is equal to the width of the inclined plate (121), and the distance between the two ends of the aeration trough (123) perpendicular to the fluid flow direction is equal to the width of the inclined plate (121).

10. An MBR wastewater treatment method, using the MBR wastewater treatment device according to claim 9, characterized in that: The wastewater treatment method is as follows: Prepare several MBR wastewater treatment units according to process requirements; Several MBR wastewater treatment units were hoisted into the bottom of the oxidation ditch, in front of the flow generator, using a crane. The gas source is connected to the aeration gas (12), the first aeration device, the second aeration device and the third aeration device respectively, and the flow rate is controlled by the regulating valve; Open the gas source regulating valve and start the flow generator. Compressed air with a certain pressure enters the lower aeration gas (12), the first aeration device, the second aeration device and the third aeration device respectively. It aerates the fluid in the oxidation ditch and flushes the four sets of MBR aeration membrane modules (11) through several lower aeration holes (124), several first aeration holes on the outer aeration pipe (3), several first aeration holes on the middle aeration pipe (4), several first aeration holes on the inner aeration pipe (5), several second aeration holes on the outer baffle ring (6), several second aeration holes on the middle baffle ring (7) and several second aeration holes on the inner baffle ring (8).

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