Sewage treatment equipment based on multistage circulation

Abstract

The invention discloses sewage treatment equipment based on multi-stage circulation, and belongs to the technical field of multi-stage sewage treatment, the sewage treatment equipment comprises a front settling tank and a treatment tank which are sequentially communicated, the treatment tank is internally provided with an anaerobic zone, an anoxic zone and an aerobic zone which are separated, and the sewage treatment equipment further comprises a plurality of zone control units which are connected in the treatment tank, and the area spaces of the anaerobic area and the anoxic area in the treatment box are controlled by a driving control unit. According to the invention, through perfect combination of flexible region division, undisturbed sludge discharge backflow, membrane body efficient filtration and self-cleaning, efficient multi-stage circulation of sewage in anaerobic, anoxic and membrane biological aerobic regions is realized, the overall efficiency of sewage treatment is greatly improved, and the service life of equipment is greatly prolonged.

Description

Technical Field

[0001] This invention belongs to the field of multi-stage wastewater treatment technology, and particularly relates to a wastewater treatment device based on multi-stage circulation. Background Technology

[0002] With increasingly stringent environmental protection requirements, wastewater treatment technologies are constantly evolving. Among them, the technology that combines multi-stage recycling processes with membrane bioreactors is widely used in municipal and industrial wastewater treatment due to its advantages such as good effluent quality, small footprint, and low sludge production.

[0003] However, in the actual operation of existing multi-stage circulating wastewater treatment equipment, during the multi-stage wastewater treatment process, it is necessary to return the sludge from the bottom of the aerobic zone to the anaerobic or anoxic zone. The existing return pumping methods are mostly direct bottom pumping. During sludge return, the aeration and purging or water flow disturbance in the aerobic zone can easily cause the bottom-sedimented sludge to spread and rise over a large area, resulting in insufficient sludge return concentration and low return efficiency. This seriously affects the biochemical efficiency of multi-stage circulating treatment. Furthermore, the volume ratio of the anaerobic and anoxic zones is often fixed by concrete walls or welded partitions. When the influent water quality changes or the wastewater treatment process parameters need to be adjusted, it is impossible to flexibly change the space size of each reaction zone, making it difficult to adapt to the multi-stage treatment needs under different operating conditions. There is room for improvement. Summary of the Invention

[0004] The purpose of this invention is to address the problem that the large-scale diffusion and upward movement of bottom-sedimented sludge in the aerobic zone leads to insufficient sludge recirculation concentration and low recirculation efficiency, which in turn seriously affects the biochemical efficiency of multi-stage circulating treatment. Therefore, this invention proposes a wastewater treatment device based on multi-stage circulation.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A wastewater treatment device based on multi-stage circulation includes a pre-sedimentation tank and a treatment tank connected in sequence. The treatment tank has separate anaerobic, anoxic, and aerobic zones. It also includes: A zone control unit, multiple of which are connected inside the processing box, controls the anaerobic and anoxic zones within the processing box. The membrane reactor unit includes a membrane tank connected to the aerobic zone. The membrane tank is connected to the anoxic zone via a pipe. The membrane reactor unit is connected to the anaerobic zone and the anoxic zone via return pipes, and the wastewater is treated in multiple stages through circulation and return.

[0006] As a further description of the above technical solution: The membrane reaction unit further includes: A support frame is provided inside the membrane pool, and multiple first fixing tubes and second fixing tubes are arranged in an array along the length direction on both sides of the inner cavity of the support frame. MBR membrane, the MBR membrane array is disposed between the first fixed tube and the second fixed tube; The support base is connected to both sides of the bottom of the inner cavity of the support frame. The top of the support base contacts the bottom of the second fixed tube first, and the top of the support base is provided with a receiving groove that matches the second fixed tube.

[0007] As a further description of the above technical solution: Also includes: The sewage discharge mechanism includes a sewage discharge guide membrane located at the bottom of the membrane tank, which guides the deposited sludge to circulate or discharge by adjusting the angle of the sewage discharge guide membrane.

[0008] As a further description of the above technical solution: The sewage discharge mechanism also includes: The lifting seat is configured to be raised and lowered and connected to the membrane tank. The lifting seat passes through the inner side of the sludge discharge guiding membrane. The movement of the lifting seat causes the sludge discharge guiding membrane to form a sludge guiding area. The sludge suction pipes are located on both sides of the bottom of the membrane tank. The sludge suction pipes are connected to the external suction pump of the sludge extraction pipe to realize the discharge of the deposited sludge.

[0009] As a further description of the above technical solution: The sewage discharge mechanism also includes: Two lifting coils are connected to both sides of the lifting seat, and a winding drive is connected to the other side of the lifting coil. The winding drive is installed inside the support frame. The slide rod is slidably connected to the slide hole starting at the end of the lifting seat, and one end of the slide rod is connected to the stepped block protruding from the inside of the support frame; The first spring is sleeved on the outside of the slide rod, and its two ends are respectively connected to the corresponding positions of the limiting plate and the lifting seat.

[0010] As a further description of the above technical solution: The sewage discharge mechanism also includes: Support rollers, two support rollers are rotatably connected in the grooves on both sides of the lifting seat, and the outside of the support rollers abuts against the inside of the sewage guide membrane. The support rollers reduce the friction of the sewage guide membrane during lifting. A lifting block is connected to the top of the sewage guide membrane, and the top of the sewage guide membrane has a groove that matches the second fixing pipe.

[0011] As a further description of the above technical solution: The area control unit includes: A partition seat, with multiple partition seats arrayed and connected within the anaerobic and anoxic zones of the treatment chamber; The partition plate is inserted into the partition seat at the corresponding position. A water passage hole is opened on one side of the partition plate. The area of ​​the anaerobic zone and the anoxic zone can be adjusted by the position of the partition plate inserted into the partition seat.

[0012] As a further description of the above technical solution: The area control unit also includes: Two sealing pads are slidably connected to the two sides of the inner cavity of the partition seat. The inner side of the sealing pad is in contact with the partition plate at the corresponding position. Guide rods are connected to both ends of the sealing pads, and the guide rods are slidably connected to the guide holes opened on one side of the partition seat. An adjusting screw is provided, with one end of the adjusting screw rotatably connected to one side of the sealing pad via a rotating shaft and bearing. A screw seat is embedded in the side wall of the partition seat corresponding to the position of the adjusting screw, and the adjusting screw is threaded into the screw seat. The position of the sealing pad is adjusted by turning the adjusting screw.

[0013] As a further description of the above technical solution: It also includes a buffer mechanism, which comprises: The tube rack consists of two tube racks that are slidably connected to the top of the support frame. The top of the tube rack has grooves, and the first fixed tube is connected to the groove.

[0014] As a further description of the above technical solution: The buffer mechanism includes: Guide rods, two guide rods are connected to the bottom sides of the tube frame, and guide sleeves are fitted on the outside of the guide rods. The guide sleeves are connected to the sliding grooves opened on both sides of the top of the support frame. The second spring is sleeved on the outside of the guide rod, and its two ends are respectively connected to the guide sleeve and the corresponding position on one side of the tube rack.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In this invention, by flexibly dividing the area, undisturbed sludge return, and combining high-efficiency membrane filtration with self-cleaning, efficient multi-stage circulation of wastewater in anaerobic, anoxic, and membrane biological aerobic zones is achieved, which greatly improves the overall efficiency of wastewater treatment and the service life of the equipment.

[0016] 2. In this invention, an innovatively designed sewage discharge mechanism utilizes a winding drive to pull the middle of the sewage discharge guiding membrane upwards, creating a slope from the center to both sides of the flat membrane layer. This flexible membrane layer guidance method not only facilitates the convergence of deposited sludge along the slope to the sludge pumping pipes on both sides, but also physically isolates the bottom sludge flow zone from the upper aeration water flow zone, effectively preventing the deposited sludge from being stirred up and dispersed by water flow disturbance. This significantly enhances the return and extraction efficiency of high-concentration sludge and the stability of multi-stage circulation, achieving flexible sludge guidance and undisturbed extraction, and improving return efficiency.

[0017] 3. In this invention, while the middle of the sewage discharge guiding membrane is lifted, the lifting block pushes the second fixed pipe, so that the originally taut MBR membrane is in a partially contracted and relaxed state. With the elastic support of the buffer mechanism, when the sludge is pumped out and aeration is carried out, the relaxed MBR membrane can vibrate frequently under the impact of the airflow. The combined treatment of relaxation and frequent vibration can shake off the stubborn sludge attached to the surface of the membrane fibers and the gaps, thereby improving the self-cleaning ability of the membrane.

[0018] 4. In this invention, by setting up a regional control unit, it has the ability to flexibly adjust the regional space. By using the array of partition seats and pluggable partition plates, the spatial ratio of anaerobic and anoxic zones can be freely adjusted according to the actual needs of the wastewater treatment process. Combined with the extrusion sealing structure of the adjusting screw and the sealing gasket, the water tightness of the partition plate after installation is ensured, and the cross-flow and backflow of water between zones caused by the gaps in the partition plate are completely avoided, thus ensuring the purity of the biochemical reaction. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a wastewater treatment device based on multi-stage circulation proposed in this invention; Figure 2 This is a schematic diagram of the lateral half-section structure of a membrane reaction unit of a wastewater treatment device based on multi-stage circulation proposed in this invention; Figure 3 The present invention proposes Figure 2 Enlarged structural diagram of section A; Figure 4 This is a schematic diagram of the split structure of the regional control unit of a wastewater treatment device based on multi-stage circulation proposed in this invention; Figure 5 This is a schematic diagram of the regional control unit structure of a wastewater treatment device based on multi-stage circulation proposed in this invention; Figure 6 This is a schematic diagram of the transverse structure of a membrane reaction unit in a wastewater treatment device based on multi-stage circulation proposed in this invention. Figure 7 The present invention proposes Figure 6 Enlarged structural diagram of section B; Figure 8 This is a schematic diagram of the assembly structure of the sewage discharge mechanism of a sewage treatment device based on multi-stage circulation proposed in this invention.

[0020] Legend: 1. Pre-sedimentation tank; 2. Treatment tank; 3. Area control unit; 301. Separator seat; 302. Separator plate; 303. Sealing pad; 304. Guide rod; 305. Adjusting screw; 4. Membrane reaction unit; 401. Support frame; 402. First fixing pipe; 403. MBR membrane; 404. Second fixing pipe; 405. Support seat; 406. Membrane tank; 5. Sewage discharge mechanism; 501. Suspension cable; 5 02. Lifting seat; 503. Support roller; 504. Slide rod; 505. First spring; 506. Limiting plate; 507. Sewage discharge guide membrane; 508. Lifting block; 509. Sludge suction pipe; 510. Winding drive component; 6. Buffer mechanism; 601. Pipe rack; 602. Guide sleeve; 603. Guide rod; 604. Second spring; 7. Stirring mechanism; 8. Equipment box; 9. Sludge extraction pipe; 10. Return pipe. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figures 1-8 The present invention provides a technical solution: a wastewater treatment device based on multi-stage circulation, comprising a pre-sedimentation tank 1 and a treatment tank 2 connected in sequence, wherein the treatment tank 2 has a separated anaerobic zone, anoxic zone and aerobic zone. It also includes: a zone control unit 3, multiple zone control units 3 are connected inside the processing box 2, and the zone control units 3 control the anaerobic zone and the anoxic zone space inside the processing box 2; The membrane reaction unit 4 includes a membrane tank 406 connected to the aerobic zone. The membrane tank 406 is connected to the anoxic zone side via a pipe. The membrane reaction unit 4 is connected to the anaerobic zone and the anoxic zone via a return pipe 10, and the wastewater is treated in multiple stages through circulation and return.

[0023] The anoxic zone is integrally connected to one side of the membrane tank 406 with a tank wall, and the bottom of the tank wall is connected to the membrane tank 406 via a water pipe. Furthermore, the treatment tank 2 has a corresponding equipment box 8 at its rear. In one embodiment, the equipment housing 8 has a corresponding electrochemical reactor for multi-stage treatment; Please see Figures 5-8 It also includes: The sewage discharge mechanism 5 includes a sewage discharge guiding membrane 507 located at the bottom of the membrane tank 406, which guides the deposited sludge to circulate or discharge by adjusting the angle of the sewage discharge guiding membrane 507. The lifting seat 502 is configured to be lifted and connected to the membrane tank 406. The lifting seat 502 passes through the inner side of the sewage guide membrane 507. The movement of the lifting seat 502 causes the sewage guide membrane 507 to form a sludge guiding area. The sludge suction pipe 509 is located on both sides of the bottom of the membrane tank 406. The sludge suction pipe 509 is connected to the external suction pump of the sludge extraction pipe 9 to realize the discharge of the deposited sludge.

[0024] Sewage discharge facility 5 also includes: The lifting coil 501 has two lifting coils 501 connected to both sides of the lifting seat 502. The other side of the lifting coil 501 is connected to a winding drive 510, which is installed inside the support frame 401. The slide rod 504 is slidably connected to the slide hole starting at the end of the lifting seat 502, and one end of the slide rod 504 is connected to the stepped block protruding from the inner side of the support frame 401. The first spring 505 is sleeved on the outside of the slide rod 504, and the two ends of the first spring 505 are respectively connected to the corresponding positions of the limiting plate 506 and the lifting seat 502. Sewage discharge facility 5 also includes: Support rollers 503 are rotatably connected to the grooves on both sides of the lifting seat 502. The outside of the support rollers 503 abuts against the inside of the sewage guide membrane 507. The support rollers 503 reduce the lifting friction of the sewage guide membrane 507. The lifting block 508 is connected to the top of the sewage guide membrane 507, and the top of the sewage guide membrane 507 is provided with a groove that matches the second fixed pipe 404; Specifically: Through the designed sewage discharge mechanism 5, the rotating end of the winding drive 510 can wind the lifting wire 501. The lifting wire 501 can pull the sewage discharge guide membrane 507 located in the middle upward. At this time, the sewage discharge guide membrane 507 can form an inclined guide from the middle to both sides, so that the sludge can flow to the sludge suction pipes 509 on both sides under the inclined guide. The liftable sewage discharge guide membrane 507 can reduce the disturbance when the sludge flows and improve the sufficiency of the return of the bottom deposited sludge. At the same time, the lifting of the sewage discharge guide membrane 507 in the middle can drive the lifting block 508 to push the second fixed pipe 404. When the second fixed pipe 404 is lifted, it can cause the MBR membrane 403 to partially shrink. The shrinking MBR membrane 403 will shrink and move during the purging and aeration after the sludge is pumped out, so as to fully aerate and remove the sludge on the surface of the MBR membrane 403. Furthermore, when the support roller 503 moves, it can reduce friction with the sewage guide membrane 507 and improve the stability of traction lifting. When the lifting seat 502 moves, it can move outside the slide bar 504 and pull the external first spring 505. The first spring 505 can use its own elasticity to pull the sewage guide membrane 507 to reset after the hoisting rope is reset.

[0025] Please see Figures 4-5 The area control unit 3 includes: Separator 301, an array of multiple separators 301 are connected to the anaerobic zone and the anoxic zone of the processing box 2; The partition plate 302 is inserted into the partition seat 301 at the corresponding position. A water passage hole is opened on one side of the partition plate 302. The area of ​​the anaerobic zone and the anoxic zone can be adjusted by the position of the partition plate 302 inserted into the partition seat 301. The area control unit 3 also includes: Two sealing pads 303 are slidably connected to the inner sides of the partition seat 301. The inner side of the sealing pad 303 is in contact with the partition plate 302 at the corresponding position. Both ends of the sealing pads 303 are connected to guide rods 304, which are slidably connected to the guide holes opened on one side of the partition seat 301. Adjusting screw 305, one end of which is rotatably connected to one side of sealing pad 303 via a rotating shaft and bearing, and a screw seat is embedded in the side wall of the partition seat 301 corresponding to the position of adjusting screw 305. Adjusting screw 305 is threadedly connected to the screw seat. The position of sealing pad 303 is adjusted by turning adjusting screw 305. Specifically: Through the designed area control unit 3, by turning the adjusting screw 305, the sealing pad 303 can be driven to fully fit the partition plate 302, thereby preventing the anaerobic zone and the anoxic zone from flowing back and converging due to the gaps in the partition plate 302, and the partition plate can maintain the flow of water from the anaerobic zone to the anoxic zone through the water passage holes; By using multiple partition seats 301 arranged in an array, the distribution areas of anaerobic and anoxic zones can be reasonably controlled by selecting the placement of the partition seats 301 at different positions, thus adapting to the regional control needs under different wastewater treatment processes. Please see Figures 2-3 Membrane reaction unit 4 also includes: A support frame 401 is disposed within the membrane tank 406. Multiple first fixing tubes 402 and second fixing tubes 404 are arranged in an array along the length direction on both sides of the inner cavity of the support frame 401. MBR membrane 403, an array of multiple MBR membranes 403 are disposed between the first fixed tube 402 and the second fixed tube 404; The support base 405 is connected to both sides of the bottom of the inner cavity of the support frame 401. The top of the support base 405 contacts the bottom of the second fixed tube 404 first. The top of the support base 405 is provided with a receiving groove that matches the second fixed tube 404. The membrane tank 406 also has a corresponding aeration pipe at the bottom of its inner cavity; Buffer mechanism 6 includes: Two tube racks 601 are slidably connected to the top sides of the support frame 401 in a height-adjustable manner. The top of the tube rack 601 is provided with grooves, and the first fixed tube 402 is connected to the grooves. Guide rod 603, two guide rods 603 are connected to the bottom sides of the tube rack 601, and guide sleeve 602 is sleeved on the outside of the guide rod 603. The guide sleeve 602 is connected to the sliding groove opened on both sides of the top of the support frame 401. The second spring 604 is sleeved on the outside of the guide rod 603, and the two ends of the second spring 604 are respectively connected to the guide sleeve 602 and the corresponding position on one side of the tube rack 601; Specifically: Through the designed buffer mechanism 6, when the second fixed tube 404 at the bottom is lifted, the pulled MBR membrane 403 can contract at this time, and the first fixed tube 402 can drive the guide rod 603 to slide in the guide sleeve 602 through the bottom tube frame 601. The movement of the guide rod 603 can pull the external second spring 604. The second spring 604 can absorb the vibration of the tube frame 601 with its own elasticity, which is beneficial to improving the placement stability of the MBR membrane 403 in the membrane tank 406.

[0026] This also includes a corresponding stirring mechanism 7 in the anaerobic zone to maintain stirring efficiency.

[0027] Furthermore, the top of the treatment box 2 is equipped with a closing component, which includes a top sealing cover plate that seals the top open end of the treatment box 2 corresponding to the anaerobic zone and the anoxic zone. A first sealing gasket is provided between the top sealing cover plate and the top edge of the treatment box 2. And a top elastic sealing strip, which is fixedly connected to the top surface of the partition plate 302. When the partition plate 302 is inserted into the corresponding partition seat 301 and the top cover is closed, the top elastic sealing strip is squeezed and deformed and tightly adheres to the inner top surface of the top cover. The water seal assembly includes a submerged inlet pipe and a submerged outlet pipe; wherein external sewage is discharged through the submerged inlet pipe that extends below the liquid surface of the anaerobic zone. In one embodiment, the anoxic zone and the aerobic zone (membrane tank 406) are connected by a U-shaped submerged water pipe.

[0028] Furthermore, in order to maintain internal pressure balance and collect the gas produced by anaerobic reaction, the shut-off component also includes a one-way exhaust valve, which is connected to the top of the top cover plate corresponding to the anaerobic zone and the anoxic zone. The one-way exhaust valve is configured to allow only the gas in the treatment box 2 to be discharged outward. The gas collection pipeline is connected to the exhaust end of the one-way exhaust valve and is used to collect the mixed gas such as biogas produced by anaerobic fermentation. This part is well-known technology in the relevant field and will not be described in detail.

[0029] Working Principle: Before operation or when water quality changes, the operator inserts the partition plate 302 into the corresponding partition seat 301 within the treatment tank 2, according to process requirements, to define the size of the anaerobic and anoxic zones. Then, the adjusting screw 305 is turned, rotating within its seat and pushing the sealing pads 303 on both sides inwards. This ensures the sealing pads 303 are tightly fitted against both sides of the partition plate 302, achieving a soft seal and preventing water from converging through gaps. After being thoroughly mixed by the stirring mechanism 7 in the anaerobic zone, the wastewater flows steadily into the anoxic zone through the water passages on the partition plate 302.

[0030] After initial sedimentation in the pre-treatment sedimentation tank 1, the wastewater sequentially enters the anaerobic zone and anoxic zone of the treatment tank 2, and finally enters the membrane tank 406 in the aerobic zone for MBR membrane biological treatment. The membrane reaction unit 4 draws filtered clean water through the first fixed pipe 402 and the second fixed pipe 404. In order to maintain the concentration and activity of sludge in the biological system, the high-concentration sludge mixture at the bottom of the membrane tank 406 is returned to the anaerobic zone and the anoxic zone through the return pipe 10, forming a multi-stage circulation treatment.

[0031] When sludge removal or high-concentration back-extraction is required, the winding drive 510 is activated. The winding drive 510 winds up the lifting cable 501, causing the lifting seat 502 to move upward along the slide bar 504 within the membrane tank 406. The upward movement of the lifting seat 502 pulls up the middle of the sludge discharge guiding membrane 507, transforming the originally flat sludge discharge guiding membrane 507 into an inclined sludge guiding area that is "high in the middle and low on both sides." At this time, the deposited sludge at the bottom, supported by gravity and the flexibility of the guiding membrane, smoothly slides down to the sludge suction pipes 509 on both sides of the bottom of the membrane tank 406 and is then extracted by the external suction pump. Due to the physical shielding of the sludge discharge guiding membrane 507, the sludge will not be disturbed by the water flow in the aerobic zone above during the sliding and accumulation process.

[0032] As the sludge discharge guiding membrane 507 is lifted to discharge sludge, its top lifting block 508 rises accordingly and fits precisely into the second fixed pipe 404 above the support base 405 inside the membrane tank 406. The second fixed pipe 404 is lifted upward, causing the MBR membrane 403 connected between the first fixed pipe 402 and the second fixed pipe 404 to change from its original tooling state to a contracted and relaxed state.

[0033] At this time, the first fixed pipe 402 above is pushed, which drives the guide rod 603 to slide upward in the guide sleeve 602 through the pipe frame 601, and compresses the second spring 604. After the sludge discharge is completed, the aeration pipe at the bottom of the membrane tank 406 is opened for air-water backwashing. A large number of bubbles rise and impact the relaxed MBR membrane 403. Under the elastic buffering and rebounding action of the second spring 604, the pipe frame 601 and the MBR membrane 403 generate high-frequency vibration (frequency vibration) with the airflow. The shaking, combined with the flushing of the bubbles, completely removes the sludge attached to the membrane fibers.

[0034] After purging, the winding drive 510 releases the lifting cable 501, and the lifting seat 502 falls downward under its own weight and the restoring pull of the first spring 505. The support roller 503 rolls during the fall, reducing friction with the drain guide membrane 507. The drain guide membrane 507 returns to its flat state, and at the same time, the second fixing tube 404 falls back into the receiving groove of the support seat 405. With the assistance of the second spring 604, the MBR membrane 403 returns to its tensioned filtration state and enters the next cycle.

[0035] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A wastewater treatment device based on multi-stage circulation, comprising a pre-sedimentation tank (1) and a treatment tank (2) connected in sequence, wherein the treatment tank (2) has a separated anaerobic zone, anoxic zone and aerobic zone, characterized in that, Also includes: A region control unit (3) is connected to the processing box (2) and controls the anaerobic and anoxic zones within the processing box (2). The membrane reaction unit (4) includes a membrane tank (406) connected to the aerobic zone. The membrane tank (406) is connected to the anoxic zone side via a pipe. The membrane reaction unit (4) is connected to the anaerobic zone and the anoxic zone via a return pipe (10) to treat wastewater through multiple stages of circulation.

2. The wastewater treatment equipment based on multi-stage circulation according to claim 1, characterized in that, The membrane reaction unit (4) further includes: A support frame (401) is provided inside the membrane pool (406). Multiple first fixing tubes (402) and second fixing tubes (404) are arranged in an array along the length direction on both sides of the inner cavity of the support frame (401). MBR membrane (403), the MBR membrane (403) array is disposed between the first fixed tube (402) and the second fixed tube (404); The support base (405) is connected to both sides of the bottom of the inner cavity of the support frame (401). The top of the support base (405) contacts the bottom of the second fixed tube (404) first. The top of the support base (405) is provided with a receiving groove that matches the second fixed tube (404).

3. A wastewater treatment device based on multi-stage circulation according to claim 2, characterized in that, Also includes: The sewage discharge mechanism (5) includes a sewage discharge guide membrane (507) located at the bottom of the membrane tank (406), which guides the deposited sludge to circulate or discharge by adjusting the angle of the sewage discharge guide membrane (507).

4. A wastewater treatment device based on multi-stage circulation according to claim 3, characterized in that, The sewage discharge mechanism (5) also includes: The lifting seat (502) is configured to be lifted and connected to the membrane tank (406). The lifting seat (502) is inserted inside the sewage guide membrane (507). The movement of the lifting seat (502) causes the sewage guide membrane (507) to form a sludge guiding area. The sludge suction pipe (509) is located on both sides of the bottom of the membrane tank (406). The sludge suction pipe (509) is configured to be connected to an external suction pump through the sludge extraction pipe (9) to achieve the discharge of deposited sludge.

5. A wastewater treatment device based on multi-stage circulation according to claim 4, characterized in that, The sewage discharge mechanism (5) also includes: Two lifting coils (501) are connected to both sides of the lifting seat (502), and a winding drive (510) is connected to the other side of the lifting coil (501). The winding drive (510) is installed inside the support frame (401). The slide rod (504) is slidably connected to the slide hole starting at the end of the lifting seat (502), and one end of the slide rod (504) is connected to the stepped block protruding inside the support frame (401); The first spring (505) is sleeved on the outside of the slide rod (504), and the two ends of the first spring (505) are respectively connected to the corresponding positions of the limiting plate (506) and the lifting seat (502).

6. A wastewater treatment device based on multi-stage circulation according to claim 4, characterized in that, The sewage discharge mechanism (5) also includes: Support rollers (503) are rotatably connected to the grooves on both sides of the lifting seat (502). The outside of the support rollers (503) abuts against the inside of the sewage guide membrane (507). The support rollers (503) reduce the friction of the sewage guide membrane (507) during lifting. A lifting block (508) is connected to the top of the sewage guide membrane (507), and the top of the sewage guide membrane (507) has a groove that matches the second fixing tube (404).

7. A wastewater treatment device based on multi-stage circulation according to claim 1, characterized in that, The area control unit (3) includes: Separator (301), an array of multiple separators (301) are connected to the anaerobic zone and the anoxic zone of the processing box (2); A partition plate (302) is inserted into a partition seat (301) at a corresponding position. A water passage hole is opened on one side of the partition plate (302). The anaerobic zone and the anoxic zone are controlled by the position of the partition plate (302) inserted into the partition seat (301).

8. A wastewater treatment device based on multi-stage circulation according to claim 7, characterized in that, The area control unit (3) also includes: Two sealing pads (303) are slidably connected to the inner sides of the partition seat (301). The inner side of the sealing pad (303) is in contact with the partition plate (302) at the corresponding position. Both ends of the sealing pad (303) are connected to guide rods (304). The guide rods (304) are slidably connected to the guide holes opened on one side of the partition seat (301). An adjusting screw (305) is provided. One end of the adjusting screw (305) is rotatably connected to one side of the sealing pad (303) via a rotating shaft and bearing. A screw seat is embedded in the side wall of the partition seat (301) corresponding to the position of the adjusting screw (305). The adjusting screw (305) is threadedly connected in the screw seat. The position of the sealing pad (303) is adjusted by turning the adjusting screw (305).

9. A wastewater treatment device based on multi-stage circulation according to claim 1, characterized in that, It also includes a buffer mechanism (6), which comprises: The tube rack (601) is slidably connected to the top sides of the support frame (401) with two tube racks (601) being adjustable. The top of the tube rack (601) is provided with grooves, and the first fixed tube (402) is connected to the groove.

10. A wastewater treatment device based on multi-stage circulation according to claim 9, characterized in that, The buffer mechanism (6) includes: Guide rod (603), two guide rods (603) are connected to the bottom sides of the tube rack (601), and guide sleeves (602) are sleeved on the outside of the guide rods (603). The guide sleeves (602) are connected to the sliding grooves opened on both sides of the top of the support frame (401). The second spring (604) is sleeved on the outside of the guide rod (603), and the two ends of the second spring (604) are respectively connected to the guide sleeve (602) and the corresponding position on one side of the tube rack (601).

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