Device and method for solving sludge bulking

Abstract

The invention relates to a device and method for solving sludge bulking, the device comprises a sludge inlet pump, a sludge inlet valve, a sludge dynamic screening device and an underflow valve which are connected in sequence, and the sludge inlet pump and the sludge inlet valve are sequentially communicated with a feed port above the sludge dynamic screening device through pipelines; an overflow port is formed in the front end of the dynamic sludge screening device, an impeller is arranged in the dynamic sludge screening device, an underflow port is formed in the tail end of the dynamic sludge screening device, and the underflow valve is arranged at the underflow port; and high-quality sludge entering the dynamic sludge screener flows out from the underflow port and low-quality sludge flows out from the overflow port under the action of the centrifugal force of the impeller. By adopting the device, the high-quality sludge and the low-quality sludge can be quickly separated without depending on the addition of medicaments and changing the operating conditions of the biochemical pool, the obtained high-quality sludge is large in particle size, low in filamentous bacterium content and good in settling performance, the occurrence of sludge bulking is avoided, and the problem of sludge bulking caused by the low-quality sludge is solved.

Description

Technical Field

[0001] The invention relates to a device and a method for solving sludge bulking, belonging to the technical field of wastewater treatment. Background Art

[0002] Once sludge bulking occurs in a sewage treatment plant, it will hinder the separation of mud and water in the secondary sedimentation tank, leading to sludge loss, deteriorating effluent quality, excessive suspended solids, and reduced treatment capacity, directly impacting the normal operation of the sewage treatment plant. Practice has shown that low temperatures increase the sludge SVI (Sludge Volume Index), leading to a predominance of filamentous bacteria and a greater tendency for sludge bulking. Low temperatures and low organic matter loading are key factors influencing sludge bulking.

[0003] To solve the problem of sludge bulking in sewage treatment plants in winter, there are currently two main conventional methods: 1. Add chemicals to improve sludge bulking. Such as flocculants, fungicides, weighting agents, etc.; 2. Change operating conditions. Such as adjusting operating parameters, adding biological selectors, etc. However, improving sludge bulking by adding chemicals has the following disadvantages: 1) Flocculants improve the sedimentation properties of sludge by forming large and tightly structured sludge flocs, but the duration of the agent is too short. To maintain sedimentation performance for a long time, the agent must be added continuously. Repeated addition of agents will increase the amount of sludge; the addition of flocculants will affect the functional bacteria of the activated sludge and affect the stable operation of the reactor. 2) Oxidants have a good control effect on sludge bulking. Their working principle is to kill filamentous bacteria that hinder sedimentation. In filamentous bacteria-inducing sludge, most filamentous bacteria are located outside the flocs and are more susceptible to oxidants than other bacteria. However, the dosage must be controlled. Most oxidants are non-selective, and excessive dosage can damage functional bacteria and even cause the disintegration of sludge flocs, resulting in reduced treatment capacity and deterioration of effluent quality. Common problems with chemical oxidants are high cost and difficulty in accurately controlling the dosage. 3) Weighting agents increase sludge production, thereby increasing subsequent treatment costs.

[0004] For changing operating conditions, there are the following disadvantages:

[0005] 1) For reactors with low loads, increasing the load to meet the nutrient needs of flocculent microorganisms, allowing them to become the dominant species, thereby controlling sludge bulking. However, increasing the load will affect pollutant treatment efficiency and increase actual operating costs. 2) Aeration rate is a crucial factor in ensuring the optimal operation of a reactor. Low DO (below 2 mg / L) is the primary factor in the rapid growth of filamentous bacteria. Filamentous bacteria have a larger surface area and can more easily access oxygen in a low DO environment, making them the dominant species. Sludge bulking caused by insufficient nutrient supply can generally be avoided by increasing the aeration rate. However, excessive aeration can also loosen the sludge floc structure. The shear forces generated by aeration can disrupt the cohesion between the floccules, causing the flocs to loosen and significantly reducing settleability. 3) While adding bioselectors can reduce bulking in activated sludge systems, it does not fundamentally solve the problem, and actual operations have not always been successful. Therefore, finding a solution to sludge bulking without adding chemicals or changing operating conditions is an urgent technical challenge. Summary of the Invention

[0006] (1) Technical issues to be resolved

[0007] In order to solve the above problems of the prior art, the present invention provides a device and method for solving sludge swelling, which can achieve the purpose of inhibiting sludge swelling without relying on the addition of chemicals or changing the operating conditions of the biochemical pool.

[0008] (2) Technical solution

[0009] In order to achieve the above objectives, the main technical solutions adopted by the present invention include:

[0010] A device for solving sludge swelling, which includes a mud inlet pump, a mud inlet valve, a sludge dynamic screener and an underflow valve connected in sequence, wherein the sludge dynamic screener includes a screener cylindrical body, a screener conical body, an impeller, a motor and a bell mouth, a feed port is provided above the screener cylindrical body, and the feed port is connected to the mud inlet valve through a pipeline; the motor is provided at the front end of the screener cylindrical body, the rear end of the screener cylindrical body is connected to the screener conical body, the impeller is provided at the inner end of the screener cylindrical body, and the motor is connected to the impeller through the motor shaft to drive the impeller to rotate; the front end of the impeller is provided with a bell mouth, the narrow end of the bell mouth is connected to the shaft sleeve, the shaft sleeve passes through the screener cylindrical body, and an overflow port is provided on the shaft sleeve on the outer side of the screener cylindrical body; the underflow valve is provided at the underflow port at the end of the screener conical body; under the action of the centrifugal force of the impeller, high-quality sludge enters the screener conical body, and low-quality sludge enters the bell mouth.

[0011] In the device as described above, preferably, a mud inlet flowmeter and a mud inlet pressure sensor are provided on the pipeline between the mud inlet pump and the mud inlet valve for measuring the sludge flow and pressure.

[0012] In the device as described above, preferably, the underflow port of the conical cylinder of the screener is connected to the underflow valve via a pipeline, and an underflow flowmeter and an underflow pressure sensor are provided on the pipeline.

[0013] In the device as described above, preferably, an overflow valve is provided on the overflow port, and an overflow pressure sensor is also provided on the pipeline between the overflow port and the overflow valve.

[0014] In the device as described above, preferably, flanges are provided at the inlet, overflow port and underflow port.

[0015] As described above, preferably, the impeller includes two circular frames, a circular baffle and a plurality of blades, the two circular frames are respectively fixedly connected to the two ends of one side of the blade, the circular baffle is fixedly connected to the other end of the blade, the plurality of blades are evenly fixed inside the ring formed by the circular frames and the circular baffle, and the center of the impeller is set to be hollow; a cross is provided at the center of the inner circular frame, the motor shaft passes through the center of the cross and is fixed to the cross, and the end of the motor shaft is fixed on the circular baffle; there is a gap between the circular baffle and the inner wall of the cylindrical body of the screen to form a high-quality sludge outlet, and the coarse mouth of the bell mouth is set to align with the hollow position of the impeller.

[0016] A method for solving sludge bulking, preferably, the sludge is passed through the sludge inlet pump of the device for solving sludge bulking as described above, and after the sludge inlet valve is opened, it flows into the sludge dynamic screener. Under the centrifugal force of the impeller of the sludge dynamic screener, the high-quality sludge enters the conical cylinder of the screener and flows out from the underflow valve and returns to the biochemical pool; the low-quality sludge enters the bell mouth as residual sludge and flows out from the overflow port.

[0017] In the above method, preferably, the rotation speed of the impeller is 1000-2000 rpm.

[0018] In the above method, preferably, the pressure of the mud inlet valve for regulating the mud inlet flow rate is 0.4-0.5 MPa.

[0019] In the above method, preferably, the underflow valve adjusts the mud outflow rate to 10-40% of the mud inflow rate; further, the underflow valve adjusts the mud outflow rate to 25-35% of the mud inflow rate.

[0020] (3) Beneficial effects

[0021] The beneficial effects of the present invention are:

[0022] The present invention provides a device for addressing sludge bulking. It uses a dynamic sludge screener to separate high-quality and low-quality sludge. The high-quality sludge is retained and returned to the biochemical tank, while the low-quality sludge is eliminated as residual sludge, thereby resolving the sludge bulking problem caused by low-quality sludge. The device and method provided by the present invention do not rely on the addition of reagents or require changes to the operating conditions of the biochemical tank. They can quickly separate high-quality and low-quality sludge, resulting in high-quality sludge with large particle size, low filamentous bacteria content, and excellent settling properties, thus avoiding the occurrence of sludge bulking and resolving the sludge bulking problem caused by low-quality sludge. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a device for solving sludge bulking in accordance with an embodiment of the present invention;

[0024] Figure 2 This is a schematic cross-sectional view of a preferred embodiment of a sludge dynamic screener;

[0025] Figure 3 A schematic longitudinal section of a preferred screen impeller;

[0026] Figure 4 The results of the sedimentation ratio test of the inlet, overflow and underflow sludge are as follows;

[0027] Figure 5 It is a dye microscopic examination picture of the inlet, overflow and underflow sludge;

[0028] Figure 6 The particle size distribution and SVI diagram of inlet, overflow and underflow sludge.

[0029] [Description of Reference Numerals]

[0030] 1: Mud pump;

[0031] 2: Mud inlet valve;

[0032] 3: Sludge dynamic screener;

[0033] 4: Underflow valve;

[0034] 5: Mud inlet flow meter;

[0035] 6: Mud inlet pressure sensor;

[0036] 7: Underflow flow meter;

[0037] 8: Overflow pressure sensor;

[0038] 9: Overflow valve;

[0039] 10: Overflow pressure sensor;

[0040] 11: cylindrical body of screener;

[0041] 12: Conical cylinder of screen;

[0042] 13: impeller;

[0043] 14: Motor;

[0044] 15: bell mouth;

[0045] 16: Motor shaft;

[0046] 17: shaft sleeve;

[0047] 18: Inlet flange;

[0048] 19: Overflow flange;

[0049] 20: bottom flow flange;

[0050] 21: Leaves. DETAILED DESCRIPTION

[0051] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods in conjunction with the accompanying drawings.

[0052] Example 1

[0053] A device for solving sludge bulking, such as Figure 1 As shown, it includes a mud feed pump 1, a mud feed valve 2, a sludge dynamic screener 3 and an underflow valve 4 connected in sequence, wherein the mud feed pump 1 and the mud feed valve 2 are connected to the feed port of the sludge dynamic screener 3 through a pipeline; a feed port is provided on the top of the sludge dynamic screener 3, an overflow port is provided at the front end of the sludge dynamic screener 3, an underflow port is provided at the end of the sludge dynamic screener 3, and an underflow valve 4 is provided at the underflow port. The function of the mud feed pump 1 is mainly to provide power to the sludge, so that the sludge generates a certain pressure to enter the subsequent process. The mud feed valve 1 can be used to cut off the flow during equipment maintenance; the sludge dynamic screener 3 is used to separate the sludge into high-quality sludge and eliminated low-quality sludge (overflow), i.e., residual sludge, under the action of the centrifugal force of the impeller. The high-quality sludge can be returned to the biochemical pool through the underflow valve 4.

[0054] Further, such as Figure 2As shown, the sludge dynamic screener includes a screener cylindrical body 11, a screener conical body 12, an impeller 13, a motor 14, and a bell mouth 15. A feed port is provided above the screener cylindrical body 11, which is connected to the mud inlet valve 2 through a pipe; the sludge enters the screener cylindrical body 11 through the feed port. The motor 14 is provided at the front end of the screener cylindrical body 11 and can be fixed to the outside of the screener cylindrical body 11 via a bracket. The rear end of the screener cylindrical body 11 is connected to the screener conical body 12. The inner end of the screener cylindrical body 11 is provided with an impeller 13. The motor is connected to the impeller 13 via a motor shaft 16 and drives the impeller 13 to rotate. The front end of the impeller 13 is provided with a bell mouth 15, which can be fixed to the inside of the screener cylindrical body via a bracket. The thick end of the bell mouth 15 is aligned with the center of the impeller, and the narrow end of the bell mouth 15 is connected to the shaft sleeve 17. The shaft sleeve 17 passes through the cylindrical body 11 of the screener, and an overflow port is opened on the shaft sleeve outside the cylindrical body 11 of the screener; the underflow valve can be arranged at the underflow port at the end of the conical body 12 of the screener or on the pipe of the underflow port.

[0055] Among them, the longitudinal section diagram of the impeller is as follows Figure 3 As shown, the impeller comprises two annular frames, a circular baffle, and a plurality of blades. The two annular frames have different diameters. The two annular frames are fixedly connected at both ends of one side of the blade, and the circular baffle is fixedly connected to the other side of the blade. A plurality of blades 21 are evenly fixed inside the outer annular shape formed by the inner and outer annular frames and the circular baffle. The blades are installed with an arc, and the arc of inclination can be 20° to 60°. The annular frames make the center of the impeller hollow, and the circular baffle makes the back of the impeller solid. A cross is provided in the middle of the inner annular frame. The motor shaft passes through the center of the cross and is fixed to the cross. The end of the motor shaft is fixed to the circular baffle. In this way, the rotation of the motor shaft drives the impeller to rotate and generate centrifugal force. There is a gap between the circular baffle and the inner wall of the cylindrical body 11 of the screener. The gap serves as the outlet for high-quality sludge (heavy sludge). This arrangement facilitates the centrifugal force generated by the sludge passing through the blades, so that the high-quality sludge flows from the heavy sludge outlet into the conical body 12 of the screener, and the overflow sludge flows from the center of the impeller into the bell mouth 15 at the front end. Specifically, the sludge is driven by the sludge feed pump through the feed port into the cylindrical body 11 of the screener, and the motor 14 drives the impeller 13 to rotate. Under the action of the forced centrifugal force generated by the impeller 13, the sludge is pressurized by the impeller, and the high-quality sludge (heavy mud) enters the conical body 12 of the screener and moves spirally to the right along the inner wall of the conical body 12 of the screener, and finally flows out through the bottom flow port; the low-quality sludge (overflow sludge, i.e. light mud) is thrown into the center position of the impeller 13 and moves to the left, and finally enters the bell mouth 15, and finally flows out from the overflow port, thereby realizing the screening of the sludge and quickly solving the problem of sludge expansion. The device is suitable for all biochemical processes and can be transformed without stopping water.

[0056] In order to further calculate the amount of sludge entering the device, Figure 1 In the embodiment, a mud inlet flowmeter 5 and a mud inlet pressure sensor 6 are provided on the pipeline between the mud inlet pump 1 and the mud inlet valve 2 for measuring the sludge flow and pressure.

[0057] In order to further measure the amount of high-quality sludge and detect the pressure of the underflow, an underflow flow meter 7 and an underflow pressure sensor 8 are installed on the pipeline between the tail end port of the cone cylinder of the screener and the underflow valve 4.

[0058] In order to effectively control or regulate the flow of overflow sludge, an overflow valve 9 is provided on the pipe connected to the overflow port. In order to effectively monitor the pressure of overflow sludge, an overflow pressure sensor 10 is also provided on the pipe between the overflow port and the overflow valve 9.

[0059] In order to ensure the sealing of all connection ports and the convenience of replacing pipe connections, Figure 2 In the embodiment, flanges are provided at the feed port, overflow port and underflow port, which are respectively an inlet flange 18, an overflow port flange 19 and an underflow port flange 20.

[0060] When the device of the present invention is in use, the specific process is as follows: the activated sludge in the biochemical pool is transported to the sludge dynamic screener 3 through the mud feed pump 1 and the mud feed valve 2. The mud feed pump 1 mainly provides power for the sludge, so that the sludge generates a certain pressure (0.4Mpa). A mud feed flowmeter 5 and a mud feed pressure sensor 6 are provided behind the mud feed pump. The mud feed flowmeter 5 is used to measure the amount of sludge entering the device; the mud feed pressure sensor 6 is used to detect whether the pressure of the mud feed can reach the required pressure, and is interlocked with the mud feed pump to ensure the pressure of the mud feed and the mud feed valve 2. The mud feed valve 2 can be used to cut off the flow when the equipment is under maintenance. The sludge enters the dynamic sludge screener 3, which is equipped with an impeller (impeller speed of 1500 rpm). The sludge is separated by the forced centrifugal force generated by the impeller. High-quality sludge directly enters the conical cylinder of the screener at the rear end and flows out from the underflow outlet. The flow rate of high-quality sludge can be adjusted by adjusting the underflow valve 4 to about 25-35% of the sludge intake. The high-quality sludge can be returned to the biochemical tank through a pipeline. The eliminated low-quality sludge (i.e., excess sludge) is thrown into the bell mouth at the front end of the impeller and flows out from the overflow port of the casing. Its flow rate can be adjusted by the overflow valve 9 to about 65-75% of the sludge intake as excess sludge, thereby achieving the purpose of improving the sludge settling performance of the biochemical tank. An underflow flowmeter 7 is installed on the high-quality sludge pipeline to measure whether the underflow flow rate is 25-35% of the sludge intake; an underflow pressure sensor 8 is used to monitor the underflow pressure, the normal value should be greater than 0.1 MPa; and the underflow valve 4 is used to regulate the underflow flow rate. The overflow pressure sensor 10 is set on the inferior sludge pipeline to monitor the overflow pressure, the normal value should be greater than 0.05Mpa, and the overflow valve 9 is used to adjust the flow of overflow sludge.

[0061] Example 2

[0062] A method for solving sludge bulking, using the device as in Example 1, the sludge is transported to the sludge dynamic screener through the sludge inlet pump for sludge screening, wherein the inlet sludge MLSS (mixed liquor suspended solids concentration) is 4000ppm, and the inlet flow rate measured by the sludge flow meter is 40m 3 / h, the inlet pressure measured by the mud pressure sensor is 0.4Mpa, the impeller speed of the sludge dynamic screener is 1500 rpm, and after the sludge is separated by the sludge dynamic screener, the underflow valve is adjusted and the underflow flow meter measures the flow rate of the return sludge to be 12m 3 / h, the overflow pressure sensor is greater than 0.1Mpa, then the amount of inferior sludge (overflow) is 28m 3 / h; the overflow pressure sensor monitors the pressure of the overflow sludge at 0.05Mpa.

[0063] The MLSS in the inferior sludge and return sludge was measured using the GB11901-89 method and is shown in Table 1 (MLSS is the suspended solids concentration of the mixed liquor, the unit is mg / L, which is used to measure the amount of activated sludge in the aeration tank).

[0064] Table 1 Screener inlet and outlet flow and sludge concentration MLSS

[0065] project Mud intake Amount of low-quality sludge (overflow) Return sludge (bottom flow) volume <![CDATA[Flow rate (m 3 / h)]]> 40 28 12 MLSS (mg / L) 4000 3300 6000

[0066] Further analysis is carried out under the above conditions, and the advantages of the present invention are as follows:

[0067] 1. Can greatly improve the sedimentation ratio of sludge (SV 30 ),

[0068] Sludge settling ratio (SV 30 ) refers to the process of quickly pouring the mixed aeration tank activated sludge mixture into a 1000ml graduated cylinder to the full mark and letting it settle for a few minutes. After 30 minutes, the volume ratio of the settled sludge to the taken mixed liquid is the sludge settling ratio (%). This indicator is a direct reflection of abnormal phenomena such as sludge bulking. Normal activated sludge (MLSS between 1500-4000mg / L) SV 30 The lower the value, the better, between 15%-30%. If it exceeds the above value, there is a risk of sludge bulking.

[0069] Table 2 below shows the data of inlet sludge, low-quality sludge (overflow sludge) and high-quality sludge (underflow sludge) settling for 30 minutes. The results are shown in the figure. Figure 4 , that is, SV 30 .

[0070] Table 2 SV of inlet, overflow and underflow sludge30 surface

[0071] project Inlet sludge Overflow sludge Underflow sludge <![CDATA[SV 30 ]]> 45％ 55％ 25％

[0072] From the above results, we can see that the SV of the inlet sludge 30 is 45%, and there is a phenomenon of sludge expansion. After the sludge is separated by the device of the present invention, the SV of the bottom flow sludge is 30 The sedimentation performance is significantly improved.

[0073] 2. Can significantly reduce the content of filamentous fungi

[0074] like Figure 5 The images show staining microscopy of inlet sludge, low-quality sludge (overflow sludge), and high-quality sludge (underflow sludge). The red bacteria represent filamentous bacteria. The images show that the filamentous bacteria content in the inlet sludge is approximately 20%. After the sludge passes through the device of the present invention, the filamentous bacteria content in the underflow sludge is significantly reduced to ≤10%, while the filamentous bacteria content in the low-quality sludge is approximately 40%. Since filamentous bacteria cause over 90% of sludge bulking, the device of the present invention can effectively address the problem of sludge bulking.

[0075] 3. Ability to recycle large particles of sludge

[0076] Smaller sludge particles are difficult to settle, which will cause turbidity in the effluent and even affect the effluent quality in serious cases. Figure 6 Figures 1 and 2 show the particle size distribution and SVI (Sludge Volume Index) data for inlet sludge, low-quality sludge (overflow sludge), and high-quality sludge (underflow sludge). SVI refers to the volume occupied by 1g of dry activated sludge after 30 minutes of settling, measured in mL / g. It represents the Sludge Volume Index and is a measure of activated sludge settling performance.

[0077] Table 3 SVI of inlet, overflow and underflow sludge

[0078] project Inlet sludge Overflow sludge Underflow sludge SVI 36.4 49.1 23.1

[0079] Depend on Figure 6 The average particle size of the sludge at the inlet was 23.7 μm. After passing through the device, the average particle size of the underflow sludge was 36 μm, and the average particle size of the overflow sludge was 13.6 μm. The underflow sludge had the largest particle size, while the overflow sludge had the smallest particle size. The underflow sludge had the smallest SVI value, while the overflow sludge had the largest SVI value.

[0080] After the sludge passes through the device of the present invention, the particle size of the underflow sludge is increased and the SVI value of the underflow sludge is effectively reduced. The mixed liquor suspended solids concentration of the underflow sludge is relatively high, which means that there are more microorganisms in the system, which helps to treat more organic pollutants; the filamentous bacteria in the underflow sludge are significantly reduced to ≤10%, which can avoid sludge swelling; it can be seen that the device of the present invention can achieve sludge screening without adding reagents, can effectively improve the sedimentation of sludge, quickly solve the problem of sludge swelling, is applicable to all biochemical processes, and can achieve non-stop water transformation to maintain stable operation of the system.

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the above-disclosed embodiments into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above-disclosed embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention shall remain within the scope of protection of the present invention.

Claims

1. A device for solving sludge bulking, characterized in that: It includes a mud inlet pump, a mud inlet valve, a sludge dynamic screener and an underflow valve connected in sequence, wherein the sludge dynamic screener includes a screener cylindrical body, a screener conical body, an impeller, a motor and a bell mouth, a feed port is provided on the top of the screener cylindrical body, and the feed port is connected to the mud inlet valve through a pipeline; the motor is arranged at the front end of the screener cylindrical body, the rear end of the screener cylindrical body is connected to the screener conical body, the impeller is arranged at the inner end of the screener cylindrical body, and the motor is connected to the impeller through the motor shaft to drive the impeller to rotate; the front end of the impeller is provided with a bell mouth, the narrow end of the bell mouth is connected to the shaft sleeve, the shaft sleeve passes through the screener cylindrical body, and an overflow port is provided on the shaft sleeve on the outside of the screener cylindrical body; the underflow valve is provided at the underflow port at the end of the screener conical body; under the action of the centrifugal force of the impeller, high-quality sludge enters the screener conical body, and low-quality sludge enters the bell mouth.

2. The device according to claim 1, wherein A mud inlet flowmeter and a mud inlet pressure sensor are provided on the pipeline between the mud inlet pump and the mud inlet valve, which are used to measure the sludge flow and pressure.

3. The device according to claim 1, wherein The bottom flow port of the conical cylinder of the screener is communicated with the bottom flow valve through a pipeline, and a bottom flow meter and a bottom flow pressure sensor are arranged on the pipeline.

4. The device according to claim 1, wherein An overflow valve is provided on the overflow port, and an overflow pressure sensor is also provided on the pipeline between the overflow port and the overflow valve.

5. The device according to claim 1, wherein Flanges are provided at the feed inlet, overflow outlet and underflow outlet.

6. The device according to any one of claims 1 to 5, characterized in that The impeller includes two circular frames, a circular baffle and multiple blades. The two circular frames are respectively fixedly connected to the two ends of one side of the blade, and the circular baffle is fixedly connected to the other end of the blade. The multiple blades are evenly fixed inside the ring formed by the circular frames and the circular baffle, and the center of the impeller is set to be hollow; a cross is provided at the center of the inner circular frame, the motor shaft passes through the center of the cross and is fixed to the cross, and the end of the motor shaft is fixed on the circular baffle; a gap is provided between the circular baffle and the inner wall of the cylindrical body of the screen to form a high-quality sludge outlet, and the thick mouth of the bell mouth is set to align with the hollow position of the impeller.

7. A method for solving sludge bulking, characterized in that: The sludge is passed through the sludge inlet pump of the device for solving sludge bulking according to any one of claims 1 to 6, and flows into the sludge dynamic screener after the sludge inlet valve is opened. Under the centrifugal force of the impeller of the sludge dynamic screener, the high-quality sludge enters the conical cylinder of the screener and flows out from the underflow valve and returns to the biochemical tank; The inferior sludge enters the bell mouth as residual sludge and flows out from the overflow port.

8. The method according to claim 7, wherein The impeller speed is 1000-2000rpm.

9. The method according to claim 7, wherein The mud inlet valve adjusts the mud inlet flow pressure to 0.4~0.5Mpa.

10. The method according to claim 7, wherein: The bottom flow valve adjusts the mud outflow rate to 10% to 40% of the mud inflow rate.

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