Coagulating sedimentation circulating device for sewage treatment and circulating method thereof

Abstract

The invention belongs to the technical field of sewage treatment, and particularly relates to a coagulating sedimentation circulating device for sewage treatment and a circulating method thereof.The coagulating sedimentation circulating device comprises a stirring tank, a sedimentation tank is arranged on one side of the stirring tank, a water outlet pipe is connected into the sedimentation tank, a chemical feeding pipe is arranged in the stirring tank, and a sewage inlet pipe is arranged in the stirring tank; a sludge outlet pipe is connected to the interior of the sedimentation tank, a sludge return pipe is fixedly connected to the sludge outlet pipe, a first electromagnetic flowmeter, a control valve and a separation box are sequentially assembled on the side wall of the sludge return pipe, and a second electromagnetic flowmeter is assembled on the sludge inlet pipe; a partition plate is fixedly connected to the inner wall of the separation box, an annular plate is rotationally connected to the top face of the separation box, and the annular plate penetrates through the separation box. A small amount of settled sludge can be discharged into the separation box, and the sludge is divided into large-granule sludge and small-granule sludge, so that the large-granule sludge and the small-granule sludge can be conveniently selected and used according to sewage treatment requirements, and impurities in sewage are assisted to settle.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a coagulation and sedimentation circulation device for sewage treatment and a circulation method thereof. Background Art

[0002] The coagulation process is the most basic and extremely important process in the treatment of industrial water and domestic sewage. By adding some agents (usually called coagulants and coagulants) to the water, the particles that are difficult to precipitate in the water can aggregate with each other to form colloids, and then combine with impurities in the water to form larger flocs. Flocs have strong adsorption capacity and can not only adsorb suspended matter, but also some bacteria and soluble substances. Through adsorption, the flocs increase in volume and sink.

[0003] In the sewage treatment process, adding a small amount of sludge can have a certain impact on the efficiency of flocculants. This practice is called "sludge recycling" or "sludge return". However, when using sludge return, the size of sludge particles has an important influence on the sedimentation effect. For example, large sludge particles usually have better sedimentation performance and can be quickly separated from sewage, which helps to improve the efficiency of sedimentation tanks. Small sludge particles usually have higher microbial activity and can more effectively degrade organic matter and improve biological treatment efficiency.

[0004] The existing method of utilizing sludge return is to directly discharge the sludge into the stirring tank to assist flocculation and sedimentation. Although it can achieve a certain flocculation and sedimentation effect, it does not set up a corresponding virtual circulation pipeline (such as Figure 8 As shown in the figure, due to the different particle size content in the discharged sludge, and the sewage comes from industrial water or domestic water, the amount of impurities and impurity characteristics in the sewage are different. If the sludge of the same standard is discharged, it is easy to cause unsatisfactory flocculation effect; for example: when the sewage contains a large amount of large particle impurities, if the discharged small particle sludge is large, the small particle sludge is not easy to form flocculation effect with the large particle impurities, which leads to poor sedimentation performance and is easily discharged from the sedimentation tank together with the upper clear water, thereby increasing the load of the treatment system. Summary of the invention

[0005] The purpose of the present invention is to provide a coagulation sedimentation circulation device for sewage treatment and a circulation method thereof, which can select a small amount of precipitated sludge and discharge it into a separation box, and divide the sludge into large-particle sludge and small-particle sludge, so as to facilitate selection and use according to sewage treatment needs and assist in the sedimentation of impurities in the sewage.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A coagulation and sedimentation circulation device for sewage treatment, comprising a stirring tank, a sedimentation tank is arranged on one side of the stirring tank, a water outlet pipe is connected to the sedimentation tank, a dosing pipe is arranged in the stirring tank, a sewage inlet pipe is arranged in the stirring tank, a mud outlet pipe is connected to the sedimentation tank, a sludge return pipe is fixedly connected to the mud outlet pipe, a first electromagnetic flowmeter, a control valve and a separation box are sequentially installed on the side wall of the sludge return pipe, and a second electromagnetic flowmeter is installed on the sewage inlet pipe;

[0008] The inner wall of the separation box is fixedly connected with a partition plate, the top surface of the separation box is rotatably connected with an annular plate, the annular plate passes through the separation box, and the top surface of the separation box is provided with a transmission assembly;

[0009] The inner cavity of the separation box is provided with a mud discharge pipe on the upper side of the partition, the mud discharge pipe is U-shaped, the side wall of the mud discharge pipe is fixedly connected with a switching pipe, the switching pipe passes through the top surface of the separation box and is movably connected thereto, the side wall of the mud discharge pipe is provided with a shaking assembly, the bottom end of the mud discharge pipe is fixedly connected with a conical tube, the inner wall of the conical tube is equipped with a filter screen, the filter screen and the conical tube are connected by bolts, and the other end of the switching tube is provided with a flow guide assembly;

[0010] The side wall of the separation box is provided with a flow dividing assembly, and the side wall of the separation box is located on the upper side of the partition and is fixedly connected with a mud inlet pipe, and the mud inlet pipe is communicated with the mud return pipe.

[0011] The transmission assembly includes a plurality of tooth blocks fixedly connected to the side wall of the annular plate, the tooth blocks are distributed in an annular array, a motor is mounted on the top surface of the separation box, a gear is fixedly connected to the motor output shaft, and the gear is meshed with the tooth blocks.

[0012] The shaking assembly includes a fixed plate fixedly connected to the side wall of the transfer tube, a wave plate fixedly connected to the top surface of the separation box, the wave plate is annular, the wave plate is concentric with the transfer tube, the fixed plate is in contact with the upper surface of the wave plate, and a rebound assembly is provided on the side wall of the transfer tube.

[0013] A movable wheel is mounted on the bottom surface of the fixed plate near the end surface, and the movable wheel abuts against the upper surface of the wave plate.

[0014] A slider is fixedly connected to the side wall of the transfer tube, a sliding groove is provided on the inner wall of the annular plate, the slider is slidably connected to the sliding groove, and a spring is fixedly connected between the bottom surface of the slider and the bottom surface of the sliding groove.

[0015] The guide assembly includes a mud discharge pump fixedly connected to the side wall of the separation box, and two guide pipes are connected to the mud discharge pump. The other end of the upper guide pipe is fixedly connected to a bellows, and the other end of the bellows is rotatably connected to a transfer pipe. The other end of the lower guide pipe extends to the inner cavity of the separation box and is located on the lower side of the partition.

[0016] The diversion assembly includes a three-way pipe fixedly connected to the side wall of the separation box, one end of the three-way pipe is connected to the sludge return pipe, and the other two ends of the three-way pipe are connected to the separation box. The other two ends of the three-way pipe are respectively located on the upper and lower sides of the partition, and the side wall of the three-way pipe is equipped with two valves.

[0017] A circulation method of a coagulation and sedimentation circulation device for sewage treatment, using the above-mentioned coagulation and sedimentation circulation device for sewage treatment, characterized in that the circulation method comprises the following steps:

[0018] S1: When sewage is discharged into the stirring tank through the sewage inlet pipe, the dosing pipe simultaneously injects flocculants and coagulants into the stirring tank, and the sewage is stirred and mixed in the stirring tank and then discharged into the sedimentation tank for sedimentation;

[0019] S2: After the sewage is flocculated and precipitated, the upper layer of clean water is discharged through the outlet pipe, and the bottom layer of sludge is discharged through the sludge outlet pipe;

[0020] S3: When the sludge is discharged, part of the sludge is introduced into the separation box through the sludge return pipe. When the sludge accumulates on the partition to a certain extent, the motor is started, and the motor drives the annular plate to rotate through the gear meshing gear block. The annular plate drives the conical pipe to rotate through the sludge discharge pipe to stir the sludge;

[0021] S4: At the same time, the sludge discharge pump is started to generate negative pressure in the sludge discharge pipe, and the fine sludge particles are transported to the lower side of the partition. The annular plate drives the sludge discharge pipe to rotate through the slider, and the sludge discharge pipe drives the fixed plate to rotate along the wave plate track. The wave structure of the wave plate is used to make the conical pipe reciprocate up and down.

[0022] S5: When it is necessary to discharge large particles of sludge into the mixing tank, open the upper valve, close the lower valve, and use the pump to transport the large particles of sludge to the sewage inlet pipe. When it is necessary to discharge small particles of sludge into the mixing tank, close the upper valve, open the lower valve, and use the pump to transport the small particles of sludge to the sewage inlet pipe to promote sewage flocculation.

[0023] The technical effects achieved by the present invention are:

[0024] A coagulation sedimentation circulation device for sewage treatment and a circulation method thereof of the present invention can select a small amount of precipitated sludge and discharge it into a separation box, and divide the sludge into large-particle sludge and small-particle sludge, so that it is convenient to select and use according to the sewage treatment needs, assist the sedimentation of impurities in the sewage, increase the sedimentation rate of impurities in the sewage, and make the effluent in the sedimentation tank stable; in addition, by discharging sludge in the stirring tank, the dosage of flocculants and coagulants can be reduced, and by circulating the sludge internally, 10%-30% of the dosage of the agents can be solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1is a schematic diagram of the overall layout of an embodiment of the present invention;

[0026] Figure 2 is a three-dimensional diagram of a separation box according to an embodiment of the present invention;

[0027] Figure 3 is a schematic cross-sectional structural diagram of a separation box according to an embodiment of the present invention;

[0028] Figure 4 is a stereoscopic diagram of a mud discharge pipe according to an embodiment of the present invention;

[0029] Figure 5 1 is a bottom view of the structure of a tapered tube according to an embodiment of the present invention;

[0030] Figure 6 is a schematic structural diagram of a corrugated plate according to an embodiment of the present invention;

[0031] Figure 7 Embodiment of the present invention Figure 3 A in the enlarged view;

[0032] Figure 8 It is a pipeline distribution diagram of sewage treatment in the prior art.

[0033] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0034] 1. Mixing tank; 2. Sedimentation tank; 3. Outlet pipe; 4. Dosing pipe; 5. Sewage inlet pipe; 6. Mud outlet pipe; 7. Sludge return pipe; 8. First electromagnetic flowmeter; 9. Control valve; 10. Second electromagnetic flowmeter; 11. Separation box; 12. Partition; 13. Annular plate; 14. Gear block; 15. Gear; 16. Motor; 17. Mud discharge pipe; 18. Conical pipe; 19. Filter screen; 20. Transfer pipe; 21. Bellows; 22. Guide pipe; 23. Mud discharge pump; 24. Sliding block; 25. Slide; 26. Spring; 27. Fixed plate; 28. Wave plate; 29. ​​Movable wheel; 30. Tee; 31. Valve; 32. Mud inlet pipe. DETAILED DESCRIPTION

[0035] In order to make the purpose and advantages of the present invention more clearly understood, the present invention is specifically described below in conjunction with embodiments. It should be understood that the following text is only used to describe one or several specific embodiments of the present invention, and does not strictly limit the scope of protection of the specific claims of the present invention.

[0036] Embodiment 1:

[0037] like Figure 1-Figure 8As shown, a coagulation and sedimentation circulation device for sewage treatment comprises a stirring tank 1, a sedimentation tank 2 is arranged on one side of the stirring tank 1, a water outlet pipe 3 is connected to the sedimentation tank 2, a dosing pipe 4 is arranged in the stirring tank 1, a sewage inlet pipe 5 is arranged in the stirring tank 1, a mud outlet pipe 6 is connected to the sedimentation tank 2, a sludge return pipe 7 is fixedly connected to the mud outlet pipe 6, a first electromagnetic flowmeter 8, a control valve 9 and a separation box 11 are sequentially installed on the side wall of the sludge return pipe 7, and a second electromagnetic flowmeter 10 is installed on the sewage inlet pipe 5;

[0038] Among them, the first electromagnetic flowmeter 8 and the second electromagnetic flowmeter 10 are both existing mature technologies, and are mainly used to monitor the flow of sewage sludge in this solution, so they are not described in detail.

[0039] A partition plate 12 is fixedly connected to the inner wall of the separation box 11, and an annular plate 13 is rotatably connected to the top surface of the separation box 11. The annular plate 13 passes through the separation box 11, and a transmission assembly is arranged on the top surface of the separation box 11;

[0040] The inner cavity of the separation box 11 is provided with a mud discharge pipe 17 on the upper side of the partition 12. The mud discharge pipe 17 is U-shaped. The side wall of the mud discharge pipe 17 is fixedly connected with a transfer pipe 20. The transfer pipe 20 passes through the top surface of the separation box 11 and is movably connected thereto. The side wall of the mud discharge pipe 17 is provided with a shaking assembly. The bottom end of the mud discharge pipe 17 is fixedly connected with a conical pipe 18. The inner wall of the conical pipe 18 is equipped with a filter screen 19. The filter screen 19 and the conical pipe 18 are connected by bolts. Through this bolt connection method, it is convenient to maintain or replace the filter screen 19 at a later stage. The other end of the transfer pipe 20 is provided with a flow guide assembly.

[0041] A flow dividing assembly is provided on the side wall of the separation box 11 , and a mud inlet pipe 32 is fixedly connected to the side wall of the separation box 11 on the upper side of the partition 12 , and the mud inlet pipe 32 is communicated with the mud return pipe 7 .

[0042] like Figure 2 and Figure 3 As shown, the transmission assembly includes a plurality of gear blocks 14 fixedly connected to the side wall of the annular plate 13, and the gear blocks 14 are distributed in an annular array. A motor 16 is mounted on the top surface of the separation box 11, and a gear 15 is fixedly connected to the output shaft of the motor 16, which meshes with the gear blocks 14.

[0043] The motor 16 and the gear 15 are arranged on the outside of the annular plate 13 , and the gear 15 is engaged with the tooth block 14 to drive the annular plate 13 to rotate, and also provide power for the up and down reciprocating movement of the tapered tube 18 .

[0044] like Figure 4 and Figure 7As shown, the shaking assembly includes a fixed plate 27 fixedly connected to the side wall of the transfer tube 20, a wave plate 28 fixedly connected to the top surface of the separation box 11, the wave plate 28 is annular, the wave plate 28 is concentric with the transfer tube 20, the fixed plate 27 contacts the upper surface of the wave plate 28, and a rebound assembly is provided on the side wall of the transfer tube 20. A movable wheel 29 is installed on the bottom surface of the fixed plate 27 near the end surface, and the movable wheel 29 abuts against the upper surface of the wave plate 28.

[0045] Specifically, when the annular plate 13 rotates, the transfer tube 20 is driven to rotate through the mud discharge pipe 17, and the transfer tube 20 drives the fixed plate 27 to rotate. When the movable wheel 29 on the fixed plate 27 moves from the lowest end of the wave plate 28 to the top, the fixed plate 27 drives the conical tube 18 to move upward through the mud discharge pipe 17. When the movable wheel 29 moves from the top to the lowest end, the conical tube 18 moves downward. The reciprocating cycle allows the conical tube 18 to rotate while performing up and down reciprocating motion, which has a shaking effect on the sludge. On the one hand, it prevents sludge particles from clogging the filter screen 19 and shakes the filter screen 19 to shake off the particulate impurities adhering to the surface of the filter screen 19. On the other hand, the discharged sludge can be mixed, and the small particle sludge can be quickly discharged into the separation box 11 on the lower side of the partition 12.

[0046] like Figure 7 As shown, a slider 24 is fixedly connected to the side wall of the transfer tube 20, a slide groove 25 is opened on the inner wall of the annular plate 13, the slider 24 is slidably connected to the slide groove 25, and a spring 26 is fixedly connected between the bottom surface of the slider 24 and the bottom surface of the slide groove 25.

[0047] When the annular plate 13 rotates, the rotational force is transmitted to the mud discharge pipe 17 through the slider 24, and when the movable wheel 29 moves from the top to the bottom, the force of the spring 26 is used to generate a downward pulling force on the fixed plate 27 to achieve a resetting effect, thereby improving stability during operation.

[0048] like Figure 2 and Figure 3 As shown, the guide assembly includes a mud pump 23 fixedly connected to the side wall of the separation box 11, and two guide pipes 22 are connected to the mud pump 23. The other end of the upper guide pipe 22 is fixedly connected to the bellows 21, and the other end of the bellows 21 is rotatably connected to the transfer pipe 20. When the transfer pipe 20 drives the fixed plate 27 to rotate, it will not drive the bellows 21 to rotate. The other end of the lower guide pipe 22 extends to the inner cavity of the separation box 11 and is located on the lower side of the partition 12.

[0049] Specifically, when the mud discharge pipe 17 drives the transfer tube 20 to reciprocate up and down, in order to avoid the movement interference of the transfer tube 20 on the guide tube 22, a bellows 21 is added at the connection position between the mud discharge pipe 17 and the transfer tube 20. The bellows 21 can be made of metal, plastic, composite material and the like, has good toughness and bending performance, and can offset the movement interference when the transfer tube 20 reciprocates up and down.

[0050] like Figure 2 and Figure 3 As shown, the diversion assembly includes a three-way pipe 30 fixedly connected to the side wall of the separation box 11, one end of the three-way pipe 30 is connected to the sludge return pipe 7, and the other two ends of the three-way pipe 30 are connected to the separation box 11. The other two ends of the three-way pipe 30 are respectively located on the upper and lower sides of the partition 12, and two valves 31 are installed on the side wall of the three-way pipe 30.

[0051] Specifically, the valves 31 on both sides are used to control the discharge state and discharge volume of large-particle sludge and small-particle sludge in the separation box 11, and selectively discharge sewage with different characteristics or sewage with different impurity contents; in addition, through the sludge reflux method, it has the characteristics of strong resistance to impact load, insensitive to influent turbidity fluctuations, and strong adaptability to low-temperature and low-turbidity raw water; and it has strong flocculation ability, fast floc sedimentation speed, and stable effluent water quality, which is mainly due to the combined application of flocculants, coagulants, and activated sludge co-flow. The hydraulic load can reach 23m3 / ㎡·h. Due to the fast sedimentation speed and short flocculation sedimentation time, it is much higher than the conventional process. Through the internal circulation of sludge, the dosage of drug consumption is relatively low, which can save 10% to 30% of the dosage of drugs.

[0052] Embodiment 2:

[0053] A circulation method of a coagulation and sedimentation circulation device for sewage treatment, using the above-mentioned coagulation and sedimentation circulation device for sewage treatment, characterized in that the circulation method comprises the following steps:

[0054] S1: When sewage is discharged into the stirring tank 1 through the sewage inlet pipe 5, the dosing pipe 4 simultaneously injects flocculants and coagulants into the stirring tank 1, and the sewage is stirred and mixed in the stirring tank 1 and then discharged into the sedimentation tank 2 for sedimentation;

[0055] S2: After the sewage is flocculated and precipitated, the upper layer of clean water is discharged through the outlet pipe 3, and the bottom layer of sludge is discharged through the sludge outlet pipe 6;

[0056] S3: When the sludge is discharged, part of the sludge is introduced into the separation box 11 through the sludge return pipe 7. When the sludge accumulates to a certain extent on the partition plate 12, the motor 16 is started. The motor 16 engages the gear block 14 through the gear 15 and drives the annular plate 13 to rotate. The annular plate 13 drives the conical pipe 18 to rotate through the sludge discharge pipe 17 to stir the sludge.

[0057] S4: At the same time, the sludge discharge pump 23 is started to generate negative pressure in the sludge discharge pipe 17, and the fine sludge particles are transported to the lower side of the partition 12. The annular plate 13 drives the sludge discharge pipe 17 to rotate through the slider 24, and the sludge discharge pipe 17 drives the fixed plate 27 to rotate along the track of the wave plate 28. The wave-shaped structure of the wave plate 28 makes the conical pipe 18 reciprocate up and down;

[0058] S5: When it is necessary to discharge large particles of sludge into the stirring tank 1, the upper valve 31 is opened, the lower valve 31 is closed, and the large particles of sludge are transported to the sewage inlet pipe 5 by a pump. When it is necessary to discharge small particles of sludge into the stirring tank 1, the upper valve 31 is closed, the lower valve 31 is opened, and the small particles of sludge are transported to the sewage inlet pipe 5 by a pump to promote sewage flocculation.

[0059] The above 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 principles of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to the conventional means in the art unless otherwise specified and limited.

Claims

1. A coagulation and sedimentation circulation device for sewage treatment, comprising a stirring tank (1), a sedimentation tank (2) is arranged on one side of the stirring tank (1), a water outlet pipe (3) is connected to the sedimentation tank (2), a dosing pipe (4) is arranged in the stirring tank (1), a sewage inlet pipe (5) is arranged in the stirring tank (1), and a mud outlet pipe (6) is connected to the sedimentation tank (2), characterized in that: The mud discharge pipe (6) is fixedly connected to a sludge return pipe (7), the side wall of the sludge return pipe (7) is sequentially equipped with a first electromagnetic flowmeter (8), a control valve (9) and a separation box (11), and the sewage inlet pipe (5) is equipped with a second electromagnetic flowmeter (10); The inner wall of the separation box (11) is fixedly connected with a partition plate (12); the top surface of the separation box (11) is rotatably connected with an annular plate (13); the annular plate (13) penetrates the separation box (11); and the top surface of the separation box (11) is provided with a transmission assembly; The inner cavity of the separation box (11) is provided with a mud discharge pipe (17) on the upper side of the partition (12), the mud discharge pipe (17) is arranged in a U shape, the side wall of the mud discharge pipe (17) is fixedly connected with a transfer pipe (20), the transfer pipe (20) passes through the top surface of the separation box (11) and is movably connected thereto, the side wall of the mud discharge pipe (17) is provided with a shaking assembly, the bottom end of the mud discharge pipe (17) is fixedly connected with a conical pipe (18), the inner wall of the conical pipe (18) is equipped with a filter screen (19), and the other end of the transfer pipe (20) is provided with a flow guide assembly; The side wall of the separation box (11) is provided with a flow dividing assembly, and the side wall of the separation box (11) is located on the upper side of the partition (12) and is fixedly connected with a mud inlet pipe (32), and the mud inlet pipe (32) is in communication with the mud return pipe (7).

2. A coagulation and sedimentation circulation device for sewage treatment according to claim 1, characterized in that: The transmission assembly comprises a plurality of tooth blocks (14) fixedly connected to the side wall of the annular plate (13), wherein the tooth blocks (14) are distributed in an annular array, and a motor (16) is mounted on the top surface of the separation box (11), wherein the output shaft of the motor (16) is fixedly connected to a gear (15), and the gear (15) meshes with the tooth blocks (14).

3. A coagulation and sedimentation circulation device for sewage treatment according to claim 1, characterized in that: The shaking assembly includes a fixed plate (27) fixedly connected to the side wall of the transfer tube (20), and the top surface of the separation box (11) is fixedly connected to a wave plate (28), the wave plate (28) is annular, the wave plate (28) is concentric with the transfer tube (20), the fixed plate (27) is in contact with the upper surface of the wave plate (28), and the side wall of the transfer tube (20) is provided with a rebound assembly.

4. A coagulation and sedimentation circulation device for sewage treatment according to claim 3, characterized in that: A movable wheel (29) is mounted on the bottom surface of the fixed plate (27) near the end surface, and the movable wheel (29) abuts against the upper surface of the wave plate (28).

5. A coagulation and sedimentation circulation device for sewage treatment according to claim 3, characterized in that: A slider (24) is fixedly connected to the side wall of the transfer tube (20), a slide groove (25) is provided on the inner wall of the annular plate (13), the slider (24) is slidably connected to the slide groove (25), and a spring (26) is fixedly connected between the bottom surface of the slider (24) and the bottom surface of the slide groove (25).

6. A coagulation and sedimentation circulation device for sewage treatment according to claim 1, characterized in that: The flow guide assembly comprises a mud discharge pump (23) fixedly connected to the side wall of the separation box (11), and two flow guide pipes (22) are connected to the mud discharge pump (23). The other end of the upper flow guide pipe (22) is fixedly connected to a bellows (21), and the other end of the bellows (21) is rotatably connected to a transfer pipe (20). The other end of the lower flow guide pipe (22) extends to the inner cavity of the separation box (11) and is located at the lower side of the partition (12).

7. A coagulation and sedimentation circulation device for sewage treatment according to claim 1, characterized in that: The flow diversion component comprises a three-way pipe (30) fixedly connected to the side wall of the separation box (11), one end of the three-way pipe (30) is connected to the sludge return pipe (7), and the other two ends of the three-way pipe (30) are connected to the separation box (11), and the other two ends of the three-way pipe (30) are respectively located on the upper and lower sides of the partition (12), and the side wall of the three-way pipe (30) is equipped with two valves (31).

8. The coagulation and sedimentation circulation device for sewage treatment according to claim 1 is characterized in that: The filter screen (19) and the conical tube (18) are connected by bolts.

9. A circulation method for a coagulation and sedimentation circulation device for sewage treatment, characterized in that: The coagulation and sedimentation circulation device for sewage treatment according to any one of claims 1 to 8 is characterized in that the circulation method comprises the following steps: S1: When sewage is discharged into the stirring tank (1) through the sewage inlet pipe (5), the dosing pipe (4) simultaneously injects flocculants and coagulants into the stirring tank (1), and the sewage is stirred and mixed in the stirring tank (1) and then discharged into the sedimentation tank (2) for sedimentation; S2: After the sewage is flocculated and precipitated, the upper layer of clear water is discharged through the water outlet pipe (3), and the bottom layer of sludge is discharged through the mud outlet pipe (6); S3: When the sludge is discharged, part of the sludge is introduced into the separation box (11) through the sludge return pipe (7). When the sludge accumulates on the partition plate (12) to a certain extent, the motor (16) is started. The motor (16) engages the gear block (14) through the gear (15) and drives the annular plate (13) to rotate. The annular plate (13) drives the conical tube (18) to rotate through the sludge discharge pipe (17) to stir the sludge. S4: At the same time, the sludge discharge pump (23) is started to generate negative pressure in the sludge discharge pipe (17), and the fine sludge particles are transported to the lower side of the partition (12). The annular plate (13) drives the sludge discharge pipe (17) to rotate through the slider (24), and the sludge discharge pipe (17) drives the fixed plate (27) to rotate along the track of the wave plate (28). The wave-shaped structure of the wave plate (28) causes the conical pipe (18) to reciprocate up and down; S5: When it is necessary to discharge large particles of sludge into the stirring tank (1), the upper valve (31) is opened, the lower valve (31) is closed, and the large particles of sludge are transported to the sewage inlet pipe (5) by a pump. When it is necessary to discharge small particles of sludge into the stirring tank (1), the upper valve (31) is closed, the lower valve (31) is opened, and the small particles of sludge are transported to the sewage inlet pipe (5) by a pump to promote sewage flocculation.

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