High-efficiency micro-sand circulating precipitation device and method thereof

Abstract

A high-efficiency micro-sand circulating sedimentation device relates to the field of wastewater treatment technology. It comprises a flocculation reaction system, a maturation reaction zone, a high-efficiency settler, a flocculant dosing device, and a micro-sand circulating system. The high-efficiency settler houses the flocculation reaction system, which includes an inner tank with a rotating stirring shaft inside. The upper part of the flocculation reaction system is a mixing reaction zone. A wastewater pipe is connected to the outside of the inner tank, and a static mixer and a check valve are installed at the upper end of the wastewater pipe. Based on traditional flocculation sedimentation tank theory, micro-sand is added to accelerate floc agglomeration and sedimentation, shortening the residence time in the sedimentation tank and achieving rapid solid-liquid separation. This invention features an integrated design, saving space and energy. The device consists of a flocculation reaction system, a maturation reaction zone, a high-efficiency settler, a flocculant dosing device, a polymer coagulant aid dosing device, a cyclone sludge separation device, a micro-sand circulating replenishment device, and a PLC electrical control system.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more specifically, to a high-efficiency micro-sand circulating sedimentation device and method. Background Technology

[0002] In recent years, with the continuous upgrading of technologies such as river and lake ecological governance and sewage treatment, solid-liquid separation sedimentation purification technology has become particularly important. Traditional sedimentation separation technology has disadvantages such as large land area, long residence time, long process flow and poor separation effect. It is especially inadequate for sedimentation separation purification treatment of high algae and high turbidity water, high algae and low turbidity water, low temperature and low turbidity water and slightly polluted water in river and lake governance. Summary of the Invention

[0003] The present invention aims to solve the shortcomings of traditional sedimentation separation technology in the prior art, such as large footprint, long residence time, long process flow and poor separation effect. In particular, it is insufficient for sedimentation separation and purification treatment of high algae and high turbidity water, high algae and low turbidity water, low temperature and low turbidity water and slightly polluted water in river and lake management.

[0004] The objectives and effects of this invention are achieved by the following specific technical means:

[0005] A high-efficiency micro-sand circulating sedimentation device comprises a flocculation reaction system, a maturation reaction zone, a high-efficiency sedimentator, a flocculant dosing device, a polymer coagulant aid dosing device, and a micro-sand circulation system. The high-efficiency sedimentator is equipped with a flocculation reaction system, which includes an inner tank. A stirring shaft is rotatably installed inside the inner tank, and a stirring paddle is installed at the upper end of the stirring shaft. A stirring motor is installed at the top of the inner tank, and the output shaft of the stirring motor is connected to the stirring shaft via a coupling. A water outlet is provided at the upper end of the inner tank. The lower end of the flocculation reaction system is designated as the flocculation reaction zone, and the upper end of the flocculation reaction system is designated as the mixing reaction zone. A sewage pipe is connected to the outside of the inner tank, and a static mixer and a check valve are installed at the upper end of the sewage pipe.

[0006] The high-efficiency precipitator has an outer barrel located outside the inner barrel, and a maturation reaction zone is formed between the inner barrel and the outer barrel.

[0007] An inclined tube packing support is installed between the lower end of the outer barrel and the outer shell of the high-efficiency precipitator. An inclined tube packing bed is set at the upper end of the inclined tube packing support. A sludge zone is set at the lower end of the inclined tube packing bed inside the outer shell. A diversion guide plate is installed in the sludge zone. A clear water zone is set at the upper end of the inclined tube packing bed inside the outer shell. A clear water zone top plate is set at the top of the clear water zone. A clear water zone outlet weir is set in the clear water zone. A clear water outlet is set on the outside of the outer shell corresponding to the clear water zone outlet weir. The top of the outer barrel is connected to the clear water zone top plate. A micro-sand accumulation zone is set at the bottom of the outer shell. A micro-sand circulation system is connected to the outside of the high-efficiency precipitator.

[0008] Preferably, the micro-sand circulation system includes a cyclone mud and sand separator, a micro-sand circulation replenishment device, and a PLC electrical control box. A sand outlet pipe is connected to the middle of the inner barrel. A pipeline mixer and an electric valve are installed at the upper end of the sand outlet pipe. The other end of the sand outlet pipe is connected to the cyclone mud and sand separator. A supply pipeline is connected between the polymer coagulant dosing device and the pipeline mixer. A micro-sand circulation pipe and a sand inlet pipe are connected between the cyclone mud and sand separator and the micro-sand aggregation area. A micro-sand circulation pump and an electric valve are installed at the upper end of the sand inlet pipe.

[0009] Preferably, the top of the cyclone sludge separator is equipped with a micro-sand circulation replenishment device and a pressure gauge, and a mud and water discharge pipe is installed on the outer side of the upper end of the cyclone sludge separator. An electric valve is installed at the upper end of the mud and water discharge pipe.

[0010] Preferably, the sewage pipe and the sand outlet pipe are positioned opposite each other and vertically as they enter the inner tank tangentially, forming a clockwise laminar vortex that is consistent with the rotation direction of the agitator.

[0011] Preferably, the water inlet is a rectangular hole, evenly distributed around the circumference of the inner barrel, with a hole diameter of 200*100mm and a spacing of 200mm. The water inlet is 200-300mm higher than the water outlet weir of the clear water zone.

[0012] Preferably, the diversion guide plate is set at the lower part of the inclined tube packing bed. The diversion guide plate is made of carbon steel lined with plastic or PE material and consists of two guide plates with different regularities. The guide plates are installed at an angle of 45 or 55°. One end of the guide plate is connected to the inner barrel and the other end is connected to the inner wall of the outer shell, with an included angle of 35 or 45°. Sand discharge holes are set in the middle and at the lower end of the two guide plates, so that the micro sand after separation of the matured sand-containing flocs sinks into the micro sand accumulation area along the discharge holes.

[0013] Preferably, a sludge discharge pipe is installed on the outside of the sludge zone, and an electric valve is installed at the upper end of the sludge discharge pipe.

[0014] Preferably, the flocculant dosing device consists of a dissolving cylinder, a mixer, a dosing pump, and a supply pipe. The mixer is installed inside the dissolving cylinder, and the supply pipe connects the dissolving cylinder and the static mixer. The dosing pump is installed at the upper end of the supply pipe.

[0015] Preferably, the polymer coagulant dosing device consists of a dissolving cylinder, a mixer, a dosing pump, and a supply pipeline.

[0016] Methods for using a high-efficiency micro-sand circulating sedimentation device:

[0017] Step 1: Sewage enters through the sewage pipe. A dosing pump and supply pipe are installed between the flocculant dosing device and the static mixer. After the flocculant is fully mixed with the sewage, it enters along the tangential direction of the inner tank and flows upward into the flocculation reaction zone. The reaction time is 1-2 minutes. The coagulant aid and circulating sand are fully mixed through the pipeline mixer and then enter along the tangential direction of the inner tank and flow upward into the mixing reaction zone. The residence time is 1-2 minutes.

[0018] Step 2: The mixing reaction zone enters the maturation reaction zone through the water inlet. Sand discharge holes are set in the middle and at the bottom of the two guide plates, so that the fine sand after the maturation of sand-containing flocs is separated and sinks into the fine sand accumulation zone along the discharge holes.

[0019] Step 3: A sludge discharge pipe is installed on the outside of the sludge zone, and an electric valve is installed at the upper end of the sludge discharge pipe. The sludge deposit layer formed in the sludge zone is discharged through the sludge discharge pipe and the electric valve.

[0020] Step 4: After flocculation, mixing, sedimentation, and separation, the heavy sludge and fine sand in the wastewater accumulate in the fine sand accumulation zone. They then enter the cyclone sludge separator via electric valve 4, the fine sand circulation pump, and the fine sand circulation inlet pipe for sludge and sand separation. The separated sludge and water are discharged from the system, while the separated fine sand is returned to the mixing reaction zone of the inner tank via a pipeline mixer. The fine sand is recycled, with a recycling rate of 5-20%.

[0021] Step 5: The micro-sand circulation and replenishment device replenishes micro-sand periodically according to usage. The lower part of the cyclone mud and sand separator is set with a conical bucket, which is the micro-sand deposition zone. The deposited micro-sand enters the mixing reaction zone in the inner tank through the sand outlet pipe, pipeline mixer, and electric valve. The coagulant aid enters the pipeline mixer through the polymer coagulant aid dosing device and supply pipeline, and enters the mixing reaction zone in the inner tank synchronously with the circulating micro-sand. Beneficial effects

[0022] 1. This invention is based on a traditional vertical flow sedimentation tank, optimizing and integrating the flocculation reaction zone into a single unit. It incorporates the concept of high-efficiency micro-sand circulation to enhance sedimentation, and fully utilizes guide plates and inclined tube packing beds. This integrated sedimentation unit forms a flocculation zone, a mixed sedimentation zone, a clear water zone, a sludge zone, a micro-sand aggregation sedimentation zone, and a micro-sand circulation system, constituting an integrated high-efficiency micro-sand sedimentation system. This accelerates flocculation and agglomeration, increases the volume of floc particles, shortens the residence time in the sedimentation tank, and achieves rapid solid-liquid separation. This device has a wide range of applications, suitable for industrial wastewater, domestic sewage, and slightly polluted water. It is particularly effective for rivers with high algae and high turbidity, high algae and low turbidity, and slightly polluted water with large treatment volumes. The integrated design of this device results in a small footprint, large treatment capacity, continuous water intake treatment, high efficiency and low consumption, intelligent control, simple management, stable and efficient water quality treatment, and cost savings.

[0023] 2. Based on the traditional coagulation sedimentation tank, the present invention adds a three-dimensional stacked flocculation dosing and stirring tank, adds a micro sand system, and combines it with the sedimentation tank to form the integrated micro sand circulation sedimentation device of the present invention.

[0024] 3. The flocculation tanks are stacked and share a single mixing device, which saves energy and equipment investment.

[0025] 4. The flocculation reaction tank and sedimentation tank are set up in a three-dimensional manner, saving space.

[0026] 5. Add a micro-sand circulation system to promote floc clumping and compaction, thereby improving separation efficiency.

[0027] 6. The rotary cutting water inlet method provides power for the flocculation reaction, saves energy, and enhances the flocculation effect.

[0028] 7. The cyclone sediment separation device enables rapid, efficient, and thorough separation of sediment and sand. Its compact layout and integrated design simplify the process and reduce system operating costs; it also reduces the footprint and facilitates maintenance and management. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the high-efficiency micro-sand circulating sedimentation device of the present invention.

[0030] Figure 2 This is a schematic diagram of the internal structure of the high-efficiency precipitator of the present invention.

[0031] Figure 1-2 In the middle section: 1. Sewage pipe; 2. Static mixer; 3. Check valve; 4. Flocculant dosing device; 5. Clear water outlet; 6. Clear water zone outlet weir; 7. Outer tank; 8. Agitator motor; 9. Agitator shaft; 10. Water outlet; 11. Inner tank; 12. Polymer coagulant dosing device; 13. Chemical supply pipe; 14. Electric valve one; 15. Microsand circulation replenishment device; 16. Pressure gauge; 17. Electric valve two; 18. Sludge discharge pipe; 19. Cyclone sludge separator; 20. Sand outlet pipe; 21. Pipeline mixer; 22. Discharge pipe. 22. Mud pipe, 23. Electric valve 3, 24. Micro-sand circulation inlet pipe, 25. Micro-sand circulation pump, 26. Electric valve 4, 27. Flocculation reaction system, 28. High-efficiency sedimentation tank, 29. PLC electrical control box, 30. Inclined tube packing bed, 31. Agitator, 32. Diverter plate, 33. Mixing reaction zone, 34. Maturation reaction zone, 35. Flocculation reaction zone, 36. Clear water zone, 37. Sludge zone, 38. Micro-sand aggregation zone, 39. Dosing pump and supply pipe, 40. Inclined tube packing support, 41. Top plate of clear water zone. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0033] Reference Figure 1-2 A high-efficiency microsand circulation sedimentation device includes a flocculation reaction system 27, a maturation reaction zone 34, a high-efficiency sedimentation tank 28, a flocculant dosing device 4, a polymer coagulant dosing device 12, and a microsand circulation system.

[0034] The micro-sand circulation system includes a cyclone mud and sand separator 19, a micro-sand circulation replenishment device 15, and a PLC electrical control box 29;

[0035] The high-efficiency precipitator 28 includes a shell, and a flocculation reaction system 27 is installed inside the shell;

[0036] The flocculation reaction system 27 includes an inner tank 11, a stirring shaft 9 is rotatably installed inside the inner tank 11, a stirring paddle 31 is installed at the upper end of the stirring shaft 9, a stirring motor 8 is installed at the top of the inner tank 11, and the output shaft of the stirring motor 8 is connected to the stirring shaft 9 through a coupling. A water outlet 10 is provided at the upper end of the inner tank 11. The lower end of the interior of the flocculation reaction system 27 is set as the flocculation reaction zone 35, and the upper end of the interior of the flocculation reaction system 27 is set as the mixing reaction zone 33. A sewage pipe 1 is connected to the outside of the inner tank 11, and a static mixer 2 and a check valve 3 are installed at the upper end of the sewage pipe 1.

[0037] The high-efficiency sedimentation tank 28 has an outer tank 7 located outside the inner tank 11, and a maturation reaction zone 34 is formed between the inner tank 11 and the outer tank 7.

[0038] An inclined tube packing support 40 is installed between the lower end of the outer barrel 7 and the outer shell of the high-efficiency sedimentation tank 28. An inclined tube packing bed 30 is set at the upper end of the inclined tube packing support 40. A sludge zone 37 is set at the lower end of the inclined tube packing bed 30 inside the outer shell. A diversion guide plate 32 is installed in the sludge zone 37. A clear water zone 36 is set at the upper end of the inclined tube packing bed 30 inside the outer shell. A clear water zone top plate 41 is set at the top of the clear water zone 36. A clear water zone outlet weir 6 is set in the clear water zone 36. A clear water outlet 5 is set on the outside of the outer shell corresponding to the clear water zone outlet weir 6. The top of the outer barrel 7 is connected to the clear water zone top plate 41. A micro-sand aggregation zone 38 is set at the bottom of the outer shell. The effective space width between the outer barrel 7 and the inner barrel 11 is 200-400mm.

[0039] One end of the sewage pipe 1 is installed at the lower end of the inner tank 11. It adopts a bottom-inlet and upflow water inlet method. The sewage is lifted by power and enters the flocculation reaction zone 35 through the sewage pipe 1, static mixer 2, and check valve 3. A dosing pump and a supply pipe 39 are set between the flocculant dosing device 4 and the static mixer 2. The flocculant enters the static mixer 2 through the flocculant dosing device 4. After being fully mixed with the sewage, it flows up into the flocculation reaction zone 35 and the mixing reaction zone 33. The water at the top of the mixing reaction zone 33 enters the maturation reaction zone 34 through the water outlet 10.

[0040] A sand outlet pipe 20 is connected to the middle of the inner tank 11. A pipe mixer 21 and an electric valve 14 are installed at the upper end of the sand outlet pipe 20. The other end of the sand outlet pipe 20 is connected to a cyclone sludge separator 19. A supply pipe 13 is connected between the polymer coagulant dosing device 12 and the pipe mixer 21. A micro-sand circulation pipe inlet pipe 24 is connected between the cyclone sludge separator 19 and the micro-sand aggregation zone 38. A micro-sand circulation pump 25 and an electric valve 26 are installed at the upper end of the micro-sand circulation pipe inlet pipe 24. After the flocculant is fully mixed with the sewage, it enters along the tangential direction of the inner tank 11 and flows upward into the flocculation reaction zone 35. The reaction time is 1-2 minutes. After the coagulant and circulating sand are fully mixed by the pipe mixer 21, they enter along the tangential direction of the inner tank 11 and flow upward into the mixing reaction zone 33. The residence time is 1-2 minutes.

[0041] Among them, the sewage pipe 1 and the sand outlet pipe 20 are arranged opposite each other and vertically when they enter the inner barrel 11 tangentially, and the resulting swirling laminar flow is clockwise, which is consistent with the rotation direction of the stirring paddle 31.

[0042] Among them, the water inlet 10 is a rectangular hole, evenly distributed around the inner barrel 11, with a hole diameter of 200*100mm and a spacing of 200mm. The water inlet 10 is 200-300mm higher than the water outlet weir 6 of the clear water zone.

[0043] The inner tank 11 of the high-efficiency sedimentator 28 can be made of materials such as fiberglass or carbon steel lined with plastic.

[0044] The sewage pipe 1 can be made of one of the following materials: PVC, PE, PPR, or carbon steel.

[0045] The inclined tube packing bed 30 is made of polypropylene (PP) material with a pipe diameter of 80mm. The upper clear water zone 36 of the inclined tube packing bed 30 has a height of 500-700mm. The clear water is discharged through the clear water zone outlet weir 6 and outlet pipe 5.

[0046] The diversion guide plate 32 is located at the lower part of the inclined tube packing bed 30. The diversion guide plate 32 is made of carbon steel lined with plastic or PE material and consists of two guide plates with different regularities. The guide plates are installed at an angle of 45 or 55°. One end of the guide plate is connected to the inner barrel 11 and the other end is connected to the inner wall of the outer shell, with an included angle of 35 or 45°. Sand discharge holes are provided in the middle and at the lower end of the two guide plates, so that the micro sand after separation of the matured sand-containing flocs sinks down to the micro sand accumulation area 38 along the leakage holes.

[0047] The sludge zone 37 is equipped with a sludge discharge pipe 22 on its outer side, and an electric valve 23 is installed at the upper end of the sludge discharge pipe 22. The sludge deposit layer formed in the sludge zone 37 is discharged through the sludge discharge pipe 22 and the electric valve 23.

[0048] The cyclone sludge separator 19 is equipped with a micro-sand circulation replenishment device 15 and a pressure gauge 16 at the top. A mud and water discharge pipe 18 is installed on the outer side of the upper end of the cyclone sludge separator 19. An electric valve 17 is installed at the upper end of the mud and water discharge pipe 18. After flocculation, mixing, sedimentation and separation, the heavy sludge and micro-sand accumulate in the micro-sand accumulation zone 38. The micro-sand enters the cyclone sludge separator 19 through the electric valve 26, the micro-sand circulation pump 25 and the micro-sand circulation inlet pipe 24 for mud and sand separation. The separated sludge and water are discharged from the system. The separated micro-sand is returned to the mixing reaction zone 33 of the inner tank 11 through the pipe mixer 21. The micro-sand is recycled, and the micro-sand recycling ratio is 5-20%.

[0049] The flocculant dosing device 4 consists of a dissolving cylinder, a mixer, a dosing pump, and a dosing pipe 39. The dissolving cylinder is equipped with a mixer, and the dosing pipe 39 connects the dissolving cylinder to the static mixer 2. The dosing pump is installed at the upper end of the dosing pipe 39. The flocculant is one or a combination of polyaluminum chloride, polyferric sulfate, and ferric chloride. Specifically, this invention uses polyaluminum chloride, and the dosage is 30-80 mg / L.

[0050] The polymeric coagulant dosing device 12 consists of a dissolving cylinder, a mixer, a dosing pump, and a supply pipeline 13. The polymeric coagulant is polyacrylamide with a molecular weight of 12,000 units and a dosage of 3-6 mg / L.

[0051] The cyclone sludge separator 19 is made of carbon steel with powder coating or rubber lining. A micro-sand circulation and replenishment device 15 is set at the top to replenish micro-sand periodically according to usage. The lower part of the cyclone sludge separator 19 is set with a conical bucket as a micro-sand deposition zone. The deposited micro-sand enters the mixing reaction zone 33 in the inner tank 11 through the sand outlet pipe 20, the pipeline mixer 21, the electric valve 23, and the coagulant through the polymer coagulant dosing device 12 and the supply pipe 13 into the pipeline mixer 21, and enters the mixing reaction zone 33 in the inner tank 11 simultaneously with the circulating micro-sand.

[0052] The PLC control box 29 controls the water inlet pump, electric valve, dosing device, stirring motor 8, micro-sand circulation pump 25 and other devices of this system, realizing intelligent control, unattended operation and reducing energy consumption.

[0053] Among them, the micro-sand is refined quartz sand with a particle size of 100-150um.

[0054] Methods for using a high-efficiency micro-sand circulating sedimentation device:

[0055] Step 1: Sewage enters through sewage pipe 1. A dosing pump and supply pipe 39 are installed between flocculant dosing device 4 and static mixer 2. After the flocculant is fully mixed with the sewage, it enters along the tangential direction of the inner tank 11 and flows upward into the flocculation reaction zone 35. The reaction time is 1-2 minutes. After the coagulant and circulating sand are fully mixed through pipe mixer 21, they enter along the tangential direction of the inner tank 11 and flow upward into the mixing reaction zone 33. The residence time is 1-2 minutes.

[0056] Step 2: The mixing reaction zone 33 enters the maturation reaction zone 34 through the water outlet 10. Sand discharge holes are set in the middle and lower ends of the two guide plates, so that the fine sand after the maturation of sand-containing flocs is separated and sinks into the fine sand accumulation zone 38 along the discharge holes.

[0057] Step 3: A sludge discharge pipe 22 is installed on the outside of the sludge zone 37. An electric valve 23 is installed at the upper end of the sludge discharge pipe 22. The sludge deposit layer formed in the sludge zone 37 is discharged through the sludge discharge pipe 22 and the electric valve 23.

[0058] Step 4: After flocculation, mixing, sedimentation, and separation, the heavy sludge and fine sand from the wastewater accumulate in the fine sand accumulation zone 38. They then enter the cyclone sludge separator 19 via the electric valve 26, the fine sand circulation pump 25, and the fine sand circulation inlet pipe 24 for sludge and sand separation. The separated sludge and water are discharged from the system, while the separated fine sand is returned to the mixing reaction zone 33 of the inner tank 11 via the pipeline mixer 21. The fine sand is recycled, with a recycling rate of 5-20%.

[0059] Step 5: The micro-sand circulation replenishment device 15 replenishes micro-sand periodically according to usage. The lower part of the cyclone mud and sand separator 19 is set with a conical bucket, which is the micro-sand deposition zone. The deposited micro-sand enters the mixing reaction zone 33 in the inner barrel 11 through the sand outlet pipe 20, the pipeline mixer 21, and the electric valve 14. The coagulant aid enters the pipeline mixer 21 through the polymer coagulant aid dosing device 12 and the supply pipeline 13, and enters the mixing reaction zone 33 in the inner barrel 11 synchronously with the circulating micro-sand.

Claims

1. A high-efficiency micro-sand circulating sedimentation device, comprising a flocculation reaction system (27), a maturation reaction zone (34), a high-efficiency sedimentator (28), a flocculant dosing device (4), a polymeric coagulant aid dosing device (12), and a micro-sand circulating system, characterized in that: The high-efficiency precipitator (28) is equipped with a flocculation reaction system (27). The flocculation reaction system (27) includes an inner barrel (11). A stirring shaft (9) is rotatably installed inside the inner barrel (11). A stirring paddle (31) is installed at the upper end of the stirring shaft (9). A stirring motor (8) is installed at the top of the inner barrel (11). The output shaft of the stirring motor (8) is connected to the stirring shaft (9) through a coupling. A water outlet (10) is provided at the upper end of the inner barrel (11). The lower end of the flocculation reaction system (27) is set as the flocculation reaction zone (35). The upper end of the flocculation reaction system (27) is set as the mixing reaction zone (33). A sewage pipe (1) is connected to the outside of the inner barrel (11). A static mixer (2) and a check valve (3) are installed at the upper end of the sewage pipe (1). The high-efficiency precipitator (28) has an outer barrel (7) located outside the inner barrel (11), and a maturation reaction zone (34) is formed between the inner barrel (11) and the outer barrel (7). An inclined tube packing support (40) is installed between the lower end of the outer barrel (7) and the outer shell of the high-efficiency precipitator (28). An inclined tube packing bed (30) is set at the upper end of the inclined tube packing support (40). A sludge zone (37) is set at the lower end of the inclined tube packing bed (30) inside the outer shell. A diversion guide plate (32) is installed in the sludge zone (37). The diversion guide plate (32) is set at the lower part of the inclined tube packing bed (30). The diversion guide plate (32) is composed of two guide plates made of carbon steel lined with plastic or PE material. The guide plates are installed at an angle of 45 or 55°. One end of the guide plate is connected to the inner barrel (11), and the other end is connected to the inner wall of the outer shell. The included angle is 35 or 45°. A sand discharge hole is set at the middle position and the lower end of the two guide plates so that the micro sand after separation of the matured sand-containing flocs sinks down to the micro sand accumulation area (38) along the leakage hole. The interior of the outer shell is located at the upper end of the inclined tube packing bed (30) and is set as a clear water zone (36). A clear water zone top plate (41) is set at the top of the clear water zone (36). A clear water zone outlet weir (6) is set inside the clear water zone (36). A clear water outlet (5) is set on the outside of the outer shell corresponding to the clear water zone outlet weir (6). The top of the outer barrel (7) is connected to the clear water zone top plate (41). A micro sand accumulation zone (38) is set at the bottom of the outer shell. A micro sand circulation system is connected to the outside of the high-efficiency sedimentation tank (28). The micro-sand circulation system includes a cyclone mud and sand separator (19), a micro-sand circulation replenishment device (15), and a PLC electrical control box (29). The middle part of the inner barrel (11) is connected to the sand outlet pipe (20). The sewage pipe (1) and the sand outlet pipe (20) enter the inner barrel (11) tangentially and are set up vertically. The cyclone laminar flow formed is clockwise and consistent with the rotation direction of the stirring paddle (31). The upper end of the sand outlet pipe (20) is equipped with a pipe mixer (21) and an electric valve (14). The other end of the sand outlet pipe (20) is connected to the cyclone mud and sand separator (19). A supply pipe (13) is connected between the polymer coagulant dosing device (12) and the pipe mixer (21). The cyclone mud and sand separator (19) and the micro-sand aggregation area (38) are connected by a micro-sand circulation pipe inlet pipe (24). The upper end of the micro-sand circulation pipe inlet pipe (24) is equipped with a micro-sand circulation pump (25) and an electric valve (26).

2. The high-efficiency micro-sand circulating sedimentation device as described in claim 1, characterized in that, The water inlet (10) is a rectangular hole, evenly distributed around the inner barrel (11), with a diameter of 200*100mm and a spacing of 200mm. The water inlet (10) is 200-300mm higher than the water outlet weir (6) of the clear water area.

3. The high-efficiency micro-sand circulating sedimentation device as described in claim 1, characterized in that, A sludge discharge pipe (22) is installed on the outside of the sludge zone (37), and an electric valve (23) is installed at the upper end of the sludge discharge pipe (22).

4. The high-efficiency micro-sand circulating sedimentation device as described in claim 1, characterized in that, The flocculant dosing device (4) consists of a dissolving cylinder, a mixer, a dosing pump and a dosing pipe (39). The dissolving cylinder is equipped with a mixer. The dissolving cylinder is connected to the static mixer (2) by the dosing pipe (39). The dosing pump is installed at the upper end of the dosing pipe (39).

5. The high-efficiency micro-sand circulating sedimentation device as described in claim 1, characterized in that, The polymer coagulant dosing device (12) consists of a dissolving cylinder, a mixer, a dosing pump, and a dosing pipeline (13).

6. The high-efficiency micro-sand circulating sedimentation device as described in claim 1, characterized in that, The top of the cyclone mud and sand separator (19) is equipped with a micro-sand circulation replenishment device (15) and a pressure gauge (16). A mud and water discharge pipe (18) is installed on the outer side of the upper end of the cyclone mud and sand separator (19). An electric valve (17) is installed at the upper end of the mud and water discharge pipe (18).

7. The method of the high-efficiency micro-sand circulating sedimentation device as described in any one of claims 1-6, wherein the steps are as follows: Step 1: Sewage enters through sewage pipe (1). A dosing pump and a supply pipe (39) are installed between the flocculant dosing device (4) and the static mixer (2). After the flocculant is fully mixed with the sewage, it enters along the tangential direction of the inner tank (11) and flows upward into the flocculation reaction zone (35). The reaction time is 1-2 minutes. After the coagulant and circulating sand are fully mixed through the pipe mixer (21), they enter along the tangential direction of the inner tank (11) and flow upward into the mixing reaction zone (33). The residence time is 1-2 minutes. Step 2: The mixing reaction zone (33) enters the maturation reaction zone (34) through the water outlet (10). Sand discharge holes are set in the middle and lower ends of the two guide plates, so that the micro sand after the maturation of sand-containing flocs is separated and sinks into the micro sand accumulation zone (38) along the discharge holes. Step 3: A sludge discharge pipe (22) is installed on the outside of the sludge zone (37), and an electric valve (23) is installed at the upper end of the sludge discharge pipe (22). The sludge deposit layer formed in the sludge zone (37) is discharged through the sludge discharge pipe (22) and the electric valve (23). Step 4: After flocculation, mixing, sedimentation and separation, the heavy sludge and micro sand in the wastewater accumulate in the micro sand accumulation zone (38). They enter the cyclone sludge separator (19) through the electric valve (26), the micro sand circulation pump (25) and the micro sand circulation inlet pipe (24) for sludge and sand separation. The separated sludge and water are discharged from the system. The separated micro sand is returned to the mixing reaction zone (33) of the inner tank (11) through the pipeline mixer (21). The micro sand is recycled and the micro sand recycling ratio is 5-20%. Step 5: Micro-sand circulation replenishment device (15) replenishes micro-sand periodically according to usage. The lower part of the cyclone mud and sand separator (19) is set with a cone-shaped bucket, which is the micro-sand deposition area. The deposited micro-sand enters the mixing reaction zone (33) in the inner barrel (11) through the sand outlet pipe (20), the pipeline mixer (21), and the electric valve (14). The coagulant enters the pipeline mixer (21) through the polymer coagulant dosing device (12) and the supply pipeline (13), and enters the mixing reaction zone (33) in the inner barrel (11) synchronously with the circulating micro-sand.

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