High-efficiency denitrification membrane biological reaction system

Abstract

The application discloses a high-efficiency denitrification membrane biological reaction system, which comprises a circular reaction tank and a pretreatment tank; the reaction tank is sequentially divided into a central reaction zone, an inner ring reaction zone and an outer ring reaction zone by circumferential partition plates; the central reaction zone is an oxygen-consuming zone, the inner ring reaction zone is an anoxic zone, and the outer ring reaction zone is sequentially divided into an aerobic zone, a membrane zone and a reflux zone by radial partition plates; the aerobic zone is sequentially divided into a plurality of aerobic zones by flow guide partition plates, one of the aerobic zones is an aerobic enhancement zone, and the aerobic enhancement zone is opposite to the membrane zone; a plurality of fluidized filler modules are arranged in the aerobic enhancement zone, and an MBR membrane group device is arranged in the membrane zone; a rotating frame is arranged at the top of the reaction tank, the fluidized filler modules in the aerobic enhancement zone and the MBR membrane group device in the membrane zone are connected with the rotating frame, and are driven by the rotating frame to rotate in the aerobic enhancement zone and the membrane zone respectively. The application can enhance the total nitrogen removal rate and reduce the aeration and reflux energy consumption.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and specifically to a high-efficiency denitrification membrane bioreactor system. Background Technology

[0002] Membrane bioreactors (MBRs) are wastewater treatment processes that integrate biochemical and membrane filtration processes. They are characterized by high-quality, stable, and controllable effluent and are widely used in the treatment and reuse of various wastewaters, including municipal sewage, industrial wastewater, and landfill leachate. During wastewater filtration in an MBR, large molecules can accumulate on the membrane surface and clog the membrane pores, leading to membrane fouling and reduced filtration efficiency. To control membrane fouling, an aeration device is installed at the bottom of the MBR membrane module for aeration and purging.

[0003] MBR membrane modules are typically combined with anoxic and aerobic tanks to form a denitrification membrane bioreactor system for biological denitrification of wastewater. Existing denitrification membrane bioreactor systems have the following problems during denitrification: (1) The membrane aeration and purging intensity is high. The dissolved oxygen in the MBR membrane tank can reach 4 to 6 mg / L. The mixed liquor in the MBR membrane tank needs to be returned to the beginning of the aerobic tank first, and then returned to the anoxic tank from the end of the aerobic tank to reduce the influence of dissolved oxygen on anoxic denitrification. The return energy consumption is high. (2) The aerobic tank has a relatively simple function and it is difficult to form an anoxic microenvironment inside the aerobic zone. Denitrification depends on the internal recirculation from the aerobic tank to the anoxic tank, resulting in low nitrogen removal efficiency. (3) The microbial types in the aerobic tank are relatively simple, and the denitrification efficiency is low under low temperature conditions. Summary of the Invention

[0004] To address the above problems, this invention provides a highly efficient denitrification membrane bioreactor system.

[0005] The technical solution adopted in this invention is: A high-efficiency denitrification membrane bioreactor system includes a circular reaction tank and a pretreatment tank; The reaction tank is divided into a central reaction zone, an inner ring reaction zone, and an outer ring reaction zone by circumferential partitions. The central reaction zone is an oxygen-deprived zone, and the inner ring reaction zone is an anoxic zone. The anoxic zone is divided into a head end and a tail end by partitions. The outer ring reaction zone is divided into an aerobic zone, a membrane zone, and a reflux zone by radial partitions. The aerobic zone is divided into several aerobic areas by flow guide partitions. Each aerobic area is connected by flow guide channels at the top or bottom of the flow guide partitions. One of the aerobic areas is the aerobic enhancement zone, which is opposite to the membrane zone. The aerobic enhancement zone is equipped with several fluidized packing modules, and the membrane zone is equipped with MBR membrane modules. A rotating frame is installed at the top of the reaction tank. The fluidized packing modules in the aerobic enhancement zone and the MBR membrane modules in the membrane zone are all connected to the rotating frame and are driven by the rotating frame to rotate in the forward and reverse directions in the aerobic enhancement zone and the membrane zone, respectively. Wastewater first enters the pretreatment tank, where solid impurities are filtered out. Then it enters the deoxygenation zone for deoxygenation reaction. After the deoxygenation reaction is completed, it enters the head of the anoxic zone and flows around the anoxic zone for denitrification reaction. After the denitrification reaction is completed, it enters the first aerobic zone and flows around the aerobic zone in sequence through each aerobic zone for nitrification reaction. After the nitrification reaction is completed, it enters the membrane zone and is filtered by the membrane module before being discharged in compliance with standards.

[0006] Furthermore, the anoxic zone has an inlet at the beginning and an overflow outlet A at the end. The deoxygenation zone is connected to the inlet of the anoxic zone through its bottom outlet. The effluent from the anoxic zone flows by gravity into the beginning of the aerobic zone through overflow outlet A. The aerobic zone has an overflow outlet B at the end. The effluent from the aerobic zone flows by gravity into the membrane zone through overflow outlet B. Wastewater overflows from the membrane zone into the return zone. A return pump is installed in the return zone, and the return pump is connected to the beginning of the anoxic zone through a return pipe.

[0007] When the effluent from the deoxygenation zone is mixed with the return liquid from the membrane tank before entering the anoxic zone, the pollutants carried in the effluent from the deoxygenation zone consume the dissolved oxygen in the return liquid before entering the anoxic zone, further reducing the impact of dissolved oxygen on denitrification in the anoxic zone.

[0008] Furthermore, the rotating frame is rotatably mounted on top of the deoxygenation zone via a rotating mechanism. The deoxygenation zone has an inlet at the top and an outlet at the bottom, with a fixed biological packing module B positioned between the inlet and outlet. Preferably, the filling rate of the fixed biological packing module B is 30% to 60% to ensure effective deoxygenation.

[0009] Furthermore, a rotary drum filter is installed in the pretreatment area, and the outlet of the rotary drum filter is connected to the inlet of the deoxygenation area through a pipe.

[0010] The preferred rotary drum filter has a filtration accuracy of 0.2 to 1 mm, which can effectively trap impurities such as fibers and hair mixed in the water.

[0011] Furthermore, a stirrer and a fixed biological packing module C are provided in the anoxic zone.

[0012] Multiple sets of agitators are preferably installed and fixedly mounted on the inner wall of the anoxic zone to prevent sludge from depositing in the anoxic zone. The filling rate of the fixed biological packing module C is preferably 30-60% to ensure effective denitrification.

[0013] Furthermore, a biochemical aeration module is installed at the bottom of the aerobic area outside the aerobic enhancement zone, and a fixed biological packing module A is installed above the biochemical aeration module. The filling rate of the fixed biological packing module A in each aerobic area gradually decreases from the inside to the outside of the aerobic area, while the aeration intensity of the biochemical aeration module gradually increases from the inside to the outside of the aerobic area. Preferably, the filling rate of the fixed biological packing module A varies within the range of 50% to 80%.

[0014] Because the outer ring has a faster flow velocity and the inner ring has a slower flow velocity, pollutants will diffuse from the inner ring sidewall to the outer ring sidewall. The aeration intensity gradually increases from the inner side to the outer side of the aerobic zone, which can make the direction of dissolved oxygen diffusion opposite to the direction of pollutant diffusion, thus achieving heterogeneous mass transfer. This is conducive to the simultaneous occurrence of nitrification and denitrification reactions and improves the nitrogen removal effect.

[0015] The high pollutant concentration near the inner ring sidewall, combined with the high-density fixed biological packing module and low aeration, helps to create a micro-anoxic environment both outside and inside the fixed biological packing module. In other words, a micro-anoxic zone is constructed inside the aerobic zone. Microorganisms in the micro-anoxic zone can use the nitrates generated by the nitrification reaction in the aerobic tank to carry out denitrification, thereby enhancing the removal of total nitrogen.

[0016] Furthermore, the fluidized packing module includes a packing frame and fluidized packing and a frame aerator disposed within the packing frame. The fluidized packing is in a fluidized state within the packing frame. All fluidized packing modules are rotatably connected to a rotating frame via a rotating bracket A, and the packing frame of each fluidized packing module is freely rotatably connected to the rotating bracket A.

[0017] The rotating support A allows the entire fluidized packing module to rotate along the central axis of the rotating support A while following the rotation of the rotating frame. It also allows each fluidized packing module to rotate along its own central axis, thereby improving the rotational flexibility of the fluidized packing module and preventing it from touching the side wall of the aerobic zone when rotating with the rotating frame.

[0018] Furthermore, the MBR membrane module includes a membrane assembly with a membrane frame disposed within the membrane frame. All MBR membrane modules are rotatably connected to the rotating frame via a rotating bracket B, and the membrane frame of each MBR membrane module is freely rotatably connected to the rotating bracket B.

[0019] The rotating support B allows the entire MBR membrane module to rotate along the central axis of the rotating support B while following the rotation of the rotating frame. Each MBR membrane module can also rotate along its own central axis, thereby improving the rotational flexibility of the MBR membrane module, preventing it from touching the sidewall of the aerobic zone when rotating with the rotating frame, and improving the membrane fiber vibration effect through its rotation, thus reducing membrane fouling.

[0020] Furthermore, the rotational speed of the rotating frame is 1.2–2.4 rad / min. By controlling the rotational speed of the rotating frame, the moving speed of the MBR membrane module and the fluidized packing module is controlled, ensuring the removal efficiency of total nitrogen and reducing membrane fouling.

[0021] Furthermore, an online dissolved oxygen meter B is installed at the beginning of the hypoxic zone, and the dissolved oxygen level of the online dissolved oxygen meter B is controlled at 0.2-0.5 mg / L.

[0022] By controlling the dissolved oxygen at the beginning of the anoxic zone, the removal effect of total nitrogen can be further enhanced.

[0023] The beneficial effects of this invention are: 1. By installing fluidized bed packing modules in the aerobic enhancement zone and fixed biological packing modules in other aerobic zones, the types of microorganisms in the aerobic zone are enriched, thus maintaining high nitrogen removal efficiency even under low-temperature conditions. A rotating frame at the top of the reaction tank drives the fluidized bed packing modules to rotate, allowing for changes in the aeration zone and creating alternating "anoxic-aerobic" zones within the aerobic enhancement zone. In the anoxic zone, microorganisms utilize the nitrates produced by aerobic nitrification for denitrification, enhancing total nitrogen removal.

[0024] 2. By setting a rotating frame at the top of the reaction tank, the MBR membrane module can be rotated, which can realize the radial and axial vibration of the MBR membrane filaments, thereby reducing membrane fouling, reducing the aeration intensity in the membrane tank, and significantly reducing energy consumption.

[0025] 3. The reduction in dissolved oxygen in the MBR membrane zone allows the biochemical sludge in the membrane tank to be directly returned to the anoxic zone, reducing the energy consumption of the return flow. Attached Figure Description

[0026] Figure 1 This is a top view schematic diagram of the efficient denitrification membrane bioreactor system of the present invention.

[0027] Figure 2 This is a front view schematic diagram of the efficient denitrification membrane bioreactor system of the present invention.

[0028] Figure 3 This is a schematic diagram of the water treatment process of the high-efficiency denitrification membrane bioreactor system of the present invention.

[0029] Figure 4 This is a schematic diagram of the connection structure between the MBR membrane module and the fluidized packing module and the rotating frame of the present invention.

[0030] Figure 5 This is a schematic diagram of the central reaction zone structure of the present invention.

[0031] Figure 6 This is a schematic diagram of the inner ring reaction zone structure of the present invention.

[0032] Figure 7 This is a schematic diagram of the outer ring reaction region structure of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and a preferred embodiment.

[0034] See Figures 1-4 A highly efficient denitrification membrane bioreactor system includes a circular reaction tank 1 and a pretreatment tank 2 located above the reaction tank 1.

[0035] The reaction tank 1 is divided into a central reaction zone 10, an inner ring reaction zone 20, and an outer ring reaction zone 30 by a first circumferential partition plate 11 and a second circumferential partition plate 12, respectively. The central reaction zone 10 is an oxygen-deprived zone, and the inner ring reaction zone 20 is an oxygen-deficient zone. The oxygen-deficient zone is divided into a head end and a tail end by a partition plate 21.

[0036] The outer ring reaction zone 30 is a circular ring with a uniform cross section. The reaction zone is divided into an aerobic zone 31, a membrane zone 32 and a reflux zone 33 by a first radial partition plate 13, a second radial partition plate 14 and a third radial partition plate 15 in sequence.

[0037] The aerobic zone 31 is divided into a first aerobic zone 311, a second aerobic zone 312, a third aerobic zone 313 and a fourth aerobic zone 314 by the flow guide baffle 16. The second aerobic zone 312 is an aerobic enhancement zone, which is opposite to the membrane zone 32.

[0038] The aerobic enhancement zone is equipped with a fluidized packing module 34, and the membrane zone 32 is equipped with an MBR membrane module 39. The top of the reaction tank is equipped with a rotating frame 3. The fluidized packing module 34 and the MBR membrane module 39 are both connected to the rotating frame 3 and are driven by the rotating frame to rotate in both directions in the aerobic enhancement zone and the membrane zone.

[0039] The pretreatment tank 2 is equipped with a rotary drum filter 21, and the outlet of the rotary drum filter is connected to the inlet of the deoxygenation zone through a pipe 22. Preferably, the filtration accuracy of the rotary drum filter is 0.2 to 1 mm, so as to effectively intercept impurities such as fibers and hair mixed in the water.

[0040] See Figure 3 In this embodiment, the first aerobic zone 311 and the second aerobic zone 312 are connected by a flow channel at the bottom of the baffle plate, the second aerobic zone 312 and the third aerobic zone 313 are connected by a flow channel at the top of the baffle plate, and the third aerobic zone 313 and the fourth aerobic zone 314 are connected by a flow channel at the bottom of the baffle plate. This design can extend the residence time of wastewater in the aerobic zone and improve the denitrification effect.

[0041] There can be several fluidized packing modules 34, such as... Figure 4Three fluidized packing modules 34 are illustrated. Each module includes a packing frame 341, fluidized packing material 343 disposed within the packing frame, and a frame aerator 342. Both the frame aerator 342 and the fluidized packing material 343 are existing technologies; for example, the fluidized packing material 343 can be made of polyethylene K1 packing. The packing frame 341 can be made of a rectangular or circular frame of shaped steel covered with wire mesh. The frame aerator 342 is fixed inside the packing frame 341 and connected to an aeration device via a flexible hose. Under the action of the frame aerator 342, the fluidized packing material 343 is fluidized within the packing frame 341. The aeration hose can be fixed to the rotating frame 3 with some slack.

[0042] All fluidized packing modules are rotatably connected to the rotating frame 3 via a rotating bracket A344, and the packing frame of each fluidized packing module is freely rotatably connected to the rotating bracket A344. Figure 4 As shown, the three fluidized packing modules 34 can be arranged in an equilateral triangle. The rotating support A344 consists of a vertical rod and three L-shaped supports that connect the vertical rod and are distributed in an equilateral triangle. The upper end of the vertical rod is rotatably connected to the rotating frame 3 through a bearing. The packing frame 341 of the fluidized packing module 34 is rotatably connected to the vertical section of the L-shaped support through a bearing.

[0043] There can be several MBR membrane modules 39, such as Figure 4 Three MBR membrane modules are illustrated. Each MBR membrane module includes a membrane frame 391 containing a membrane module 392. The membrane frame 391 and the packing frame 341 have essentially the same structure. The membrane module 392 is fixed inside the membrane frame 391, and its outlet is connected to a flexible hose, which is fixed to the rotating frame 3 with some slack. All MBR membrane modules are rotatably connected to the rotating frame 3 via a rotating bracket B393, and the membrane frame of each MBR membrane module is freely rotatably connected to the rotating bracket B. The structure of the rotating bracket B393 is the same as that of the rotating bracket A344. The MBR membrane modules 392 and the fluidized packing module 34 are symmetrically distributed at both ends of the rotating frame 3.

[0044] See Figure 5 The central reaction zone 10, i.e., the deoxygenation zone, is a stepped cylindrical shape, wider at the top and narrower at the bottom. An inlet 101 is located on the upper side of the larger cylindrical section, and an outlet 102 is located on the lower side of the smaller cylindrical section. A fixed biological packing module B103 is installed inside the smaller cylindrical section. The fixed biological packing module B is existing technology; for example, polyvinylidene fluoride (PVDF) biological rope packing can be used. The preferred filling rate of the fixed biological packing module B is 30-60%. The outlet 102 is located at the beginning of the anoxic zone. The deoxygenation zone is connected to the beginning of the anoxic zone through the outlet 102, and to the outlet of the rotary drum filter 21 through the inlet 101.

[0045] The rotating frame 3 is rotatably mounted at the center of the central reaction zone 10 via a rotating mechanism. The rotating mechanism includes a motor, a reducer, a coupling, and a rotating shaft. The motor drives the rotating shaft to rotate via the reducer and coupling. The rotating shaft is fixedly connected to the rotating frame 3, causing the rotating frame 3 to rotate. Preferably, the rotational speed of the rotating frame is controlled to be 1.2–2.4 rad / min.

[0046] See Figure 6 The inner ring reaction zone 20, also known as the anoxic zone, is a circular ring with a uniform cross-section. The anoxic zone is divided into a head end and a tail end by a partition plate 21. The anoxic zone is equipped with a stirrer 22 and a fixed biological packing module C23. Multiple sets of stirrers 22 can be installed and fixedly mounted on the inner wall of the anoxic zone to prevent sludge deposition. The fixed biological packing module C23 is existing technology and can consist of several biological packing ropes arranged radially along the reaction tank, with a filling rate of 30-60%.

[0047] The anoxic zone has a return port 24 on the upper part of the first side wall, i.e. the second circumferential partition plate 12, and an overflow port A25 on the upper part of the tail side wall. The anoxic zone is connected to the first aerobic zone 311 through the overflow port A25. The liquid level in the aerobic zone is lower than that in the anoxic zone. The sewage in the anoxic zone flows into the aerobic zone by gravity through the overflow port A25.

[0048] See Figure 7 The fourth aerobic zone 314 is equipped with an overflow port B37, which is formed by the upper opening of the second radial partition plate 14. The fourth aerobic zone 314 is connected to the membrane zone 32 through the overflow port B37. The liquid level in the membrane zone 32 is lower than the liquid level in the fourth aerobic zone 314, and the effluent from the aerobic zone flows into the membrane zone by gravity through the overflow port B37. The bottom elevation of the overflow port B37 is lower than that of the overflow port A25.

[0049] Membrane zone 32 is equipped with an overflow port C38, which is formed by the upper opening of the third radial partition plate 15. Membrane zone 32 is connected to reflux zone 33 through overflow port C38. The liquid level in reflux zone 33 is lower than that in membrane zone, and the mud-water mixture in membrane zone 32 flows into reflux zone 33 by gravity through overflow port C38. The bottom elevation of overflow port C38 is lower than that of overflow port B37. Reflux pump 331 is installed in reflux zone 33, and the outlet of reflux pump 331 is connected to anoxic zone reflux port 24 through a reflux pipe.

[0050] The first aerobic zone 311, the third aerobic zone 313, and the fourth aerobic zone 314 are each equipped with a fixed biological packing module A35 and a biochemical aeration module 36; the biochemical aeration module 36 is located at the bottom of the aerobic zone.

[0051] The flow guide baffles 16 are arranged radially along the reaction tank, dividing each aerobic zone into a fan-shaped ring. The filling rate of the fixed biological packing module A35 gradually decreases from the inside to the outside of the aerobic zone, while the aeration intensity of the biochemical aeration module 36 gradually increases from the inside to the outside of the aerobic zone. In specific implementation, such as... Figure 7 As shown, the fixed biological packing module A35 is existing technology, and can be composed of several biological packing ropes arranged radially along the reaction tank. The biochemical aeration module 36 consists of a main aeration pipe arranged radially along the reaction tank and several aeration branch pipes evenly arranged along the main aeration pipe, with each aeration branch pipe extending as far as possible into the entire aerobic zone. The main aeration pipe is connected to an aeration blower.

[0052] Because the aerobic zones are divided into fan-shaped rings by the flow guide baffles 16, the above design naturally results in a higher density and lower aeration intensity of the biological packing material near the inner side of the aerobic zone, and a lower density and higher aeration intensity of the biological packing material near the outer side of the aerobic zone. The biological packing material ropes and aeration pipes both utilize existing technology.

[0053] An online dissolved oxygen meter B (not shown in the figure) is installed at the beginning of the hypoxic zone. The dissolved oxygen of the online dissolved oxygen meter B is controlled at 0.2-0.5 mg / L.

[0054] The working principle of this invention is: See Figure 3 Wastewater first enters the pretreatment tank 2, where solid impurities are filtered out by the rotary drum filter 21. After that, it flows by gravity through pipe 22 into the deoxygenation zone for deoxygenation reaction. After the deoxygenation reaction is completed, it enters the first end of the anoxic zone through outlet 102 and flows counterclockwise along the circumference of the anoxic zone for denitrification. After the denitrification reaction is completed, it flows by gravity through overflow outlet A25 into the first aerobic zone 311. It then flows clockwise along the circumference of the aerobic zone through the first aerobic zone 311, the second aerobic zone 312, the third aerobic zone 313, and the fourth aerobic zone 314 for nitrification reaction. After the nitrification reaction is completed, it enters the membrane zone 32 through overflow outlet B37. After being filtered by the membrane module, the purified water meets the discharge standards. The mud-water mixture in the membrane zone 32 enters the return zone 33 through overflow outlet C38 and is returned to the anoxic zone through return outlet 24 via return pump 331.

[0055] During the reaction of wastewater in the reactor, the rotating frame 3 drives the fluidized packing module 34 and the MBR membrane module 39 to rotate back and forth in the aerobic enhancement zone and the membrane zone, respectively. The rotation of the fluidized packing module 34 creates alternating "anoxic-aerobic" zones in the aerobic enhancement zone. Microorganisms in the anoxic zone use the nitrates generated by the nitrification reaction in the aerobic tank for denitrification, thereby enhancing the removal of total nitrogen. The rotation of the MBR membrane module causes the MBR membrane fibers to vibrate radially and axially, thus controlling membrane fouling.

[0056] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also within the protection scope of the present invention.

Claims

1. A highly efficient denitrification membrane bioreactor system, characterized in that, Includes a circular reaction tank and a pretreatment tank; The reaction tank is divided into a central reaction zone, an inner ring reaction zone, and an outer ring reaction zone by circumferential partitions. The central reaction zone is an oxygen-deprived zone, and the inner ring reaction zone is an anoxic zone. The anoxic zone is divided into a head end and a tail end by partitions. The outer ring reaction zone is divided into an aerobic zone, a membrane zone, and a reflux zone by radial partitions. The aerobic zone is divided into several aerobic areas by flow guide partitions. Each aerobic area is connected by flow guide channels at the top or bottom of the flow guide partitions. One of the aerobic areas is the aerobic enhancement zone, which is opposite to the membrane zone. The aerobic enhancement zone is equipped with several fluidized packing modules. Each fluidized packing module includes a packing frame and fluidized packing and a frame aerator located within the packing frame. The fluidized packing is in a fluidized state within the packing frame. The membrane zone is equipped with an MBR membrane module. A rotating frame is located at the top of the reactor. The fluidized packing modules in the aerobic enhancement zone and the MBR membrane module in the membrane zone are both connected to the rotating frame. The rotating frame drives them to rotate in opposite directions in the aerobic enhancement zone and the membrane zone, respectively, creating alternating "anoxic-aerobic" zones in the aerobic enhancement zone. A biochemical aeration module is installed at the bottom of the aerobic area outside the aerobic enhancement zone, and a fixed biological packing module A is installed above the biochemical aeration module; Wastewater first enters the pretreatment tank, where solid impurities are filtered out. Then it enters the deoxygenation zone for deoxygenation reaction. After the deoxygenation reaction is completed, it enters the head of the anoxic zone and flows around the anoxic zone for denitrification reaction. After the denitrification reaction is completed, it enters the first aerobic zone and flows around the aerobic zone in sequence through each aerobic zone for nitrification reaction. After the nitrification reaction is completed, it enters the membrane zone and is filtered by the membrane module before being discharged in compliance with standards.

2. The high-efficiency denitrification membrane bioreactor system according to claim 1, characterized in that, The anoxic zone has an inlet at the beginning and an overflow outlet A at the end. The deoxygenated zone is connected to the inlet of the anoxic zone through its bottom outlet. The effluent from the anoxic zone flows by gravity into the beginning of the aerobic zone through overflow outlet A. The aerobic zone has an overflow outlet B at the end. The effluent from the aerobic zone flows by gravity into the membrane zone through overflow outlet B. Wastewater overflows from the membrane zone into the return zone. The return zone is equipped with a return pump, which is connected to the beginning of the anoxic zone through a return pipe.

3. The high-efficiency denitrification membrane bioreactor system according to claim 1, characterized in that, The rotating frame can be rotatably installed on the top of the deoxygenation zone via a rotating mechanism. The deoxygenation zone has an inlet at the top and an outlet at the bottom. A fixed biological packing module B is installed between the inlet and the outlet.

4. The high-efficiency denitrification membrane bioreactor system according to claim 1, characterized in that, The pretreatment area is equipped with a drum filter, and the outlet of the drum filter is connected to the inlet of the deoxygenation area through a pipe.

5. The high-efficiency denitrification membrane bioreactor system according to claim 1, characterized in that, The anoxic zone is equipped with a stirrer and a fixed biological packing module C.

6. The high-efficiency denitrification membrane bioreactor system according to claim 1, characterized in that, The filling rate of the fixed biological packing module A in each aerobic zone gradually decreases from the inside to the outside of the aerobic zone, while the aeration intensity of the biochemical aeration module gradually increases from the inside to the outside of the aerobic zone.

7. The high-efficiency denitrification membrane bioreactor system according to claim 1, characterized in that, All fluidized packing modules are rotatably connected to the rotating frame via a rotating bracket A, and the packing frame of each fluidized packing module is freely rotatably connected to the rotating bracket A.

8. The high-efficiency denitrification membrane bioreactor system according to claim 1, characterized in that, The MBR membrane module includes a membrane frame housing a membrane assembly. All MBR membrane modules are rotatably connected to the rotating frame via a rotating bracket B, and the membrane frame of each MBR membrane module is freely rotatably connected to the rotating bracket B.

9. The high-efficiency denitrification membrane bioreactor system according to claim 1, characterized in that, The rotational speed of the rotating frame is 1.2 to 2.4 rad / min.

10. The high-efficiency denitrification membrane bioreactor system according to claim 1, characterized in that, An online dissolved oxygen meter B is installed at the beginning of the hypoxic zone, and the dissolved oxygen level of the online dissolved oxygen meter B is controlled at 0.2-0.5 mg / L.

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