Impurity removal and sludge concentration system suitable for MBR (Membrane Bioreactor) process

Abstract

The invention discloses an impurity removal and sludge concentration system suitable for an MBR (Membrane Biological Reactor) process, which comprises an MBR membrane pool, a driving pump, a sludge concentration tank, a cyclone separator and a water inlet adsorber, and an electromagnet is arranged in the water inlet adsorber and is used for removing metal impurities in sludge; the water inlet adsorber is a built-in water inlet adsorber or an external water inlet adsorber, the water inlet adsorber is used for realizing primary impurity removal of activated sludge, the activated sludge after impurity removal enters the cyclone separator for primary impurity removal and concentration, an upper-layer activated sludge mixed solution flows back to the MBR membrane tank, and a lower-layer mixture enters the sludge concentration tank for secondary impurity removal and concentration; and the supernatant flows back to the MBR membrane tank, and the lower-layer mixture is discharged. The device has the characteristics of being compact in structure, convenient to operate, high in reliability and the like, impurity removal and concentration of activated sludge are integrally designed, the activated sludge is concentrated twice, the discharge efficiency of residual sludge is improved, and the moisture content of subsequent sludge treatment is reduced.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more specifically to a sludge removal and thickening system suitable for MBR processes. Background Technology

[0002] MBR (Membrane Bio-Reactor) technology is an advanced wastewater treatment technology that efficiently combines membrane separation technology with traditional biological treatment technology (activated sludge process). It uses membrane modules to replace the secondary sedimentation tank in the traditional activated sludge process, achieving highly efficient solid-liquid separation.

[0003] MBR (Membrane Bioreactor) processes are mainly divided into biodegradation and membrane separation. Biodegradation refers to the process where organic pollutants in wastewater are decomposed and oxidized into carbon dioxide, water, and other harmless substances by the microbial community (mainly bacteria) in activated sludge within a bioreactor. Simultaneously, specific bacteria such as nitrifying bacteria can convert pollutants like ammonia nitrogen. Membrane separation refers to the process where the biotreated mixture (water and activated sludge) is forced through a membrane module with specific pore sizes under pressure (pump suction or level difference). The MBR membrane acts like a precision sieve, efficiently retaining almost all suspended solids, colloids, activated sludge bacteria, and large organic molecules, allowing only clear water molecules to pass through, thus obtaining effluent with excellent quality.

[0004] Plate and frame filter press dewatering is a common method to increase the solids content of sludge. However, during daily operation, plate and frame presses inevitably experience fabric breakage, leading to some impurities from the sludge entering the filtrate. These impurities, such as sludge, fibers, and iron filings, enter the MBR system. Additionally, if the filtrate has high hardness, it will generate a large amount of calcium carbonate particles upon entering the biological treatment tank. These impurities result in low MLVSS / MLSS ratios in the activated sludge. Furthermore, impurities in the biological treatment system scratch the ultrafiltration membrane, causing frequent membrane rupture and affecting the normal operation of the MBR process. Due to the high concentration of pollutants and long SRT (sludge retention time) in the influent of this type of wastewater, using dewatering equipment for sludge discharge is very inefficient at removing these impurities. Moreover, because the daily influent volume exceeds the sludge discharge volume, the amount of impurities carried away by the daily sludge discharge is also low.

[0005] In the MBR process, existing sludge thickening and dewatering devices, such as centrifugal dewatering machines, screw presses, and flocculation sedimentation extrusion systems, have the following drawbacks: (1) In the MBR system, the concentration of pollutants in the influent is high and the sludge retention time is long. Removing impurities such as iron filings, fine sand and fibers by dewatering the sludge is inefficient and difficult to effectively remove such impurities.

[0006] (2) Traditional external MBR membrane filtration devices such as filter screens and self-cleaning filter screens cannot effectively remove fine particles, iron filings and other impurities, and cannot protect the MBR membrane.

[0007] (3) Traditional built-in MBR membranes have low efficiency in removing impurities and do not have a secondary sedimentation tank, so impurities are easy to accumulate. Summary of the Invention

[0008] The technical problem to be solved by this invention is that impurities such as iron filings and small hard particles can easily damage the ultrafiltration membrane in the existing MBR process. The invention provides a compact, easy-to-operate impurity removal and sludge thickening system suitable for MBR process that is conducive to improving the amount of impurities removed.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A sludge removal and thickening system suitable for MBR process includes an MBR membrane tank, a drive pump, a sludge thickening tank, a hydrocyclone separator, and an influent adsorber, wherein the influent adsorber is equipped with an electromagnet. The feed water adsorber is a built-in feed water adsorber, which is installed inside the MBR membrane tank. The drive pump, sludge thickening tank, and hydrocyclone are all installed outside the MBR membrane tank. The input end of the drive pump is connected to the built-in feed water adsorber, and the output end of the drive pump is connected to the hydrocyclone. The hydrocyclone is nested inside the sludge thickening tank, and the bottom of the hydrocyclone is connected to the sludge thickening tank. The activated sludge in the MBR membrane tank enters the built-in feed water adsorber for initial impurity removal and is then transported by the drive pump to the hydrocyclone to achieve primary impurity removal and concentration. The resulting upper mixed liquor is returned to the MBR membrane tank, and the resulting lower mixed liquor enters the sludge thickening tank to achieve secondary impurity removal and concentration. The resulting supernatant is returned to the MBR membrane tank, and the resulting lower mixed liquor is discharged. Alternatively, the feed water adsorber is an external feed water adsorber. The external feed water adsorber, drive pump, sludge thickening tank, and hydrocyclone are all located outside the MBR membrane tank. The input end of the drive pump is connected to the MBR membrane tank, and the output end of the drive pump is connected to the external feed water adsorber. The external feed water adsorber is connected to the hydrocyclone, which is nested inside the sludge thickening tank. The bottom of the hydrocyclone is connected to the sludge thickening tank. The activated sludge in the MBR membrane tank is transported to the external feed water adsorber by the drive pump for initial impurity removal. The resulting impurities are discharged. The resulting activated sludge mixture is transported to the hydrocyclone for primary impurity removal and concentration. The resulting upper mixture is returned to the MBR membrane tank, and the resulting lower mixture enters the sludge thickening tank for secondary impurity removal and concentration. The resulting supernatant is returned to the MBR membrane tank, and the resulting lower mixture is discharged.

[0010] As a further improvement of the present invention, the built-in water inlet adsorber includes an inner baffle, a support frame, an outer baffle, and a driving component; the electromagnet is disposed inside the outer baffle, the support frame is disposed on the top of the outer baffle, the driving component is mounted on the support frame, and the output end of the driving component is connected to the inner baffle to drive the inner baffle to reciprocate up and down inside the outer baffle to open or close the water inlet hole on the side wall of the outer baffle.

[0011] As a further improvement of the present invention, the bottom of the outer baffle is conical, and the bottom of the outer baffle is connected to the drive pump through a water inlet pipe.

[0012] As a further improvement of the present invention, the driving component is a cylinder or an electric motor.

[0013] As a further improvement of the present invention, limit sensors are provided on both the upper and lower parts of the inner baffle.

[0014] As a further improvement of the present invention, the external water inlet adsorber includes a tank, an outlet pipe, a connecting pipe with an inlet valve, and an outlet pipe with an outlet valve. The side of the tank is connected to the output end of the drive pump through the connecting pipe, the top of the tank is connected to the hydrocyclone separator through the outlet pipe, the bottom of the tank is provided with a sludge discharge branch pipe with a sludge discharge valve, and an electromagnet is provided inside the tank. The inlet end of the outlet pipe is connected in parallel with the connecting pipe, and the parallel connection is located at the front end of the inlet valve. The outlet end of the outlet pipe is connected to the outlet pipe.

[0015] As a further improvement of the present invention, the electromagnet, the inlet valve, the bypass valve, and the sludge discharge valve are linked for control; when the electromagnet reaches the set adsorption time, the bypass valve automatically opens, the inlet valve automatically closes, and the sludge discharge valve on the sludge discharge branch pipe automatically opens; when the sludge discharge is completed, the sludge discharge valve automatically closes, the inlet valve automatically opens, and the bypass valve automatically closes.

[0016] As a further improvement of the present invention, the bottom of the cyclone separator is provided with a sand settling nozzle, and the middle of the sand settling nozzle is provided with a chemical dosing port. The chemical dosing port is connected to a chemical dosing pipe to realize the addition of flocculant into the sand settling nozzle. The addition of flocculant is linked to the drive pump for control, so as to open or close simultaneously.

[0017] As a further improvement of the present invention, the sludge thickening tank is provided with multiple inclined plates in the middle and upper part along the vertical direction, and the hydrocyclone separator is fixed in the sludge thickening tank through the inclined plates; the sludge thickening tank is provided with a water distribution pipe at the bottom, and the sand settling nozzle is connected to the water distribution pipe; the sludge thickening tank is provided with a sludge discharge pipe at the bottom, and a clear liquid pipe is provided on the side of the sludge thickening tank, and the clear liquid pipe is located above the inclined plates.

[0018] As a further improvement of the present invention, the inlet flow rate of the cyclone separator is controlled to be 5 m / s to 12 m / s.

[0019] Compared with the prior art, the advantages of the present invention are as follows: The present invention provides a sludge removal and thickening system for MBR processes. By installing an electromagnet in the influent adsorber, iron filings mixed in with activated sludge can be adsorbed and removed. The activated sludge is then transported to a hydrocyclone separator, where sand, calcium carbonate crystals, and other impurities are discharged from the bottom of the hydrocyclone separator into a sludge thickening tank. This is the first thickening. The treated upper layer of activated sludge can be returned to the MBR membrane tank for a second thickening in the sludge thickening tank to further improve the separation effect between sludge and impurities. The supernatant produced in the sludge thickening tank can be returned to the MBR membrane tank again, while impurities are discharged from the bottom of the sludge thickening tank. This invention integrates an influent adsorber, a hydrocyclone separator, and a sludge thickening tank to remove impurities such as iron filings, fine sand, and fibers from the MBR system, while also achieving sludge thickening. This effectively increases the MLVSS / MLSS ratio, enhances the organic content in the activated sludge, and solves problems such as easy accumulation of impurities, easy damage to the ultrafiltration membrane, and low efficiency of residual sludge discharge in existing MBR processes. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating the structural principle of the impurity removal and sludge thickening system of the built-in MBR process in a specific embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the structural principle of the inner baffle in the built-in water inlet adsorber in a specific embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the structural principle of the electromagnet in the built-in water inlet adsorber in a specific embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the structural principle of the outer baffle in the built-in water inlet adsorber in a specific embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the structural principle of the external MBR process for impurity removal and sludge thickening in a specific embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the structural principle of the external water inlet adsorber in a specific embodiment of the present invention; Figure 7 This is a schematic diagram of the structural principle of the sludge thickening tank in a specific embodiment of the present invention.

[0021] Legend: 1. MBR membrane tank; 2. Built-in feed water adsorber; 21. Cylinder; 22. Inner baffle; 23. Air inlet; 24. Support frame; 25. Outer baffle; 26. Water inlet hole; 3. Drive pump; 4. Sludge thickening tank; 41. Inclined plate; 42. Water distribution pipe; 5. Water inlet pipe; 6. Cyclone separator; 61. Sand settling nozzle; 7. Overflow pipe; 8. Chemical dosing pipe; 9. Clarified liquid pipe; 10. Sludge discharge pipe; 101. Electric valve; 11. Electromagnet; 12. External feed water adsorber; 120. Tank body; 121. Connecting pipe; 122. Water inlet valve; 123. Overpass valve; 124. Overpass pipe; 125. Water outlet pipe; 126. Sludge discharge branch pipe; 127. Sludge discharge valve. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0023] In the description of this invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more unless otherwise explicitly specified.

[0025] Example 1 like Figure 1As shown, the impurity removal and sludge thickening system of the present invention, applicable to MBR process, mainly consists of two parts: influent adsorption and cyclone thickening. It includes an MBR membrane tank 1, a built-in influent adsorber 2, a drive pump 3, a sludge thickening tank 4, and a cyclone separator 6. The built-in influent adsorber 2 is located inside the MBR membrane tank 1, while the drive pump 3, sludge thickening tank 4, and cyclone separator 6 are all located outside the MBR membrane tank 1. The built-in influent adsorber is equipped with an electromagnet 11 to adsorb iron filings impurities mixed in with the activated sludge. The input end of the drive pump 3 is connected to the built-in influent adsorber 2, and the output end of the drive pump 3 is connected to the cyclone separator 6. The cyclone separator 6 is nested inside the sludge thickening tank 4, and its bottom is connected to the sludge thickening tank 4. The activated sludge in MBR membrane tank 1 enters the built-in influent adsorber 2 for initial impurity removal, and is then transported by drive pump 3 to hydrocyclone separator 6 for primary impurity removal and concentration. The resulting upper mixed liquor is returned to MBR membrane tank 1 through overflow pipe 7, and the resulting lower mixed liquor enters sludge thickening tank 4 for secondary impurity removal and concentration. The resulting supernatant is returned to MBR membrane tank 1 through clear liquid pipe 9, and the resulting lower mixed liquor is discharged. In this embodiment, drive pump 3 can specifically be a centrifugal pump.

[0026] The impurity removal and sludge thickening system in this embodiment effectively removes sharp impurities such as iron filings, gravel, or calcium carbonate crystals that can easily scratch the MBR membrane, protecting the MBR membrane and preventing impurity accumulation. The activated sludge is thickened twice by the hydrocyclone separator 6 and the sludge thickening tank 4, improving the efficiency of excess sludge discharge and reducing the moisture content of subsequent sludge treatment. like Figure 2 , Figure 3 and Figure 4 As shown, the built-in water inlet adsorber 2 includes a cylinder 21, an inner baffle 22, a support frame 24, and an outer baffle 25. The outer baffle 25 is fixed to the bottom or wall of the MBR membrane tank 1 by a bracket. An electromagnet 11 is installed inside the outer baffle 25, and the support frame 24 is installed on top of the outer baffle 25. The cylinder 21 is mounted on the support frame 24, and its output end is connected to the inner baffle 22. The cylinder 21 has two air inlets 23, and the inner baffle 22 is moved up and down by compressed air. By driving the inner baffle 22 to reciprocate inside the outer baffle 25, the water inlet holes 26 on the side wall of the outer baffle 25 are opened or closed.

[0027] It is known that in the built-in water inlet adsorber 2, the cylinder 21 and below need to be completely submerged in the activated sludge, and the support frame 24 of appropriate length can be matched according to the liquid level fluctuation of the biological system. In other embodiments, the driving component can also be a reciprocating motor, as long as it can drive the inner baffle 22 to move back and forth smoothly.

[0028] In this embodiment, the electromagnet 11 is automatically controlled by a PLC and linked with the cylinder 21. By setting the adsorption time and stop time of the electromagnet 11, the maximum adsorption effect is ensured and automated operation is achieved.

[0029] like Figure 4 As shown, the bottom of the outer baffle 25 has a conical structure, and the bottom of the outer baffle 25 is connected to the drive pump 3 through the water inlet pipe 5. The diameter of the water inlet hole 26 on the side wall of the outer baffle 25 is greater than 20mm to ensure that the activated sludge can flow quickly, increase the contact area between the activated sludge and the electromagnet 11, and facilitate the electromagnet 11 to better adsorb iron filings in the MBR membrane tank 1.

[0030] In this embodiment, limit sensors (not shown in the figure) are provided at the upper and lower parts of the inner baffle 22 to ensure that when moving downward, the inner baffle 22 can effectively block the water inlet hole 26 on the side wall of the outer baffle 25, and when moving upward, the inner baffle 22 can completely expose the water inlet hole 26 on the side wall of the outer baffle 25.

[0031] like Figure 7 As shown, the hydrocyclone 6 has a settling nozzle 61 at its bottom, and a dosing port in the middle of the settling nozzle 61. The dosing port is connected to the dosing pipe 8 to allow flocculant to be added into the settling nozzle 61. The wastewater at the bottom of the hydrocyclone 6 flows out in a rotating manner under centrifugal force, allowing for thorough mixing with the flocculant. Furthermore, the flocculant addition is linked to the drive pump 3 for simultaneous on / off control, improving the impurity removal effect.

[0032] In this embodiment, the inlet flow rate of the cyclone separator 6 is controlled at 5 m / s to 12 m / s to ensure a better sand removal effect.

[0033] like Figure 7 As shown, the sludge thickening tank 4 has multiple inclined plates 41 vertically arranged in the middle and upper parts, and the hydrocyclone separator 6 is fixed inside the sludge thickening tank 4 through the inclined plates 41. A water distribution pipe 42 is provided at the lower part of the sludge thickening tank 4, and a sedimentation nozzle 61 is connected to the water distribution pipe 42. Since 90% of the impurities in the biological system are mainly fine particles, the sediment discharged from the sedimentation nozzle 61 enters the sludge thickening tank 4 through the densely distributed small holes around the water distribution pipe 42 (the hole diameter must be larger than the particle size of the main impurities in the biological system during design), so as to achieve uniform distribution of sediment within the sludge thickening tank 4. Given that the outlet of the sedimentation nozzle 61 has a certain dynamic force, the sediment will not settle in the water distribution pipe 42 under the force of the dynamic force.

[0034] like Figure 7As shown, the sludge thickening tank 4 is equipped with a sludge discharge pipe 10 at the bottom, and an electric valve 101 is installed on the sludge discharge pipe 10. The concentrated sludge at the bottom is discharged by setting the opening time of the electric valve 101. A clear liquid pipe 9 is provided on the side of the sludge thickening tank 4, and the clear liquid pipe 9 is located above the inclined plate 41. The clear liquid pipe 9 is connected to the MBR membrane tank 1 to realize the supernatant return.

[0035] In this embodiment, the working process of the impurity removal and sludge thickening system is as follows: S1: Start the drive pump 3 and start the electromagnet 11. The activated sludge in the aerated state passes through the outer baffle 25 in the built-in water inlet adsorber 2, and the iron filings in the activated sludge are adsorbed onto the electromagnet 11. When the set time is reached, the cylinder 21 drives the inner baffle 22 to move downward, blocking the water inlet hole 26 on the outer baffle 25. The activated sludge can only enter the built-in water inlet adsorber 2 through the top. At the same time, the electromagnet 11 is de-energized, and the adsorbed iron filings can only enter the bottom of the built-in water inlet adsorber 2 and be pumped away by the drive pump 3 to enter the next step. After the set time is reached, the cylinder 21 drives the inner baffle 22 to move upward, and the activated sludge enters the built-in water inlet adsorber 2 through the water inlet hole 26 on the outer baffle 25. This process is repeated.

[0036] S2: Drive pump 3 to transport the activated sludge from the MBR membrane tank 1 into the built-in feed water adsorber 2 and the iron filings adsorbed by electromagnet 11 to the hydrocyclone separator 6. Through hydrocyclone separation, the sand, calcium carbonate crystals, iron filings, and concentrated sludge in the activated sludge are discharged from the bottom sand outlet. This is the first concentration. The treated activated sludge returns to the MBR membrane tank 1 or enters the subsequent external MBR membrane through the overflow pipe 7 at the top of the hydrocyclone separator 6.

[0037] S3: Add flocculant to the settling nozzle 61 of the hydrocyclone 6 through the dosing pipe 8. Under the action of centrifugal force, the mixed sludge at the bottom of the hydrocyclone 6 is in a rotating state, mixing impurities, iron filings, concentrated sludge and flocculant. The mixed sludge enters the water distribution pipe 42 of the concentration tank 4.

[0038] S4: After the mixed sludge enters the distribution pipe 42 in the thickening tank 4, it is evenly distributed at the bottom of the thickening tank 4 for sedimentation. The concentrated sludge, impurities, and iron filings sink downwards after hitting the inclined plate 41, undergoing a second thickening. The supernatant flows out from the upper clear liquid pipe 9 after passing through the inclined plate 11, with an upward flow velocity of 5-9 m / h, and returns to the MBR membrane tank 1.

[0039] Example 2 like Figure 5As shown, the sludge removal and thickening system for MBR processes of the present invention has a similar structural configuration and working principle to the system in Example 1. The main difference is that the influent adsorber is an external influent adsorber 12. The external influent adsorber 12, the drive pump 3, the sludge thickening tank 4, and the hydrocyclone 6 are all located outside the MBR membrane tank 1. The input end of the drive pump 3 is connected to the MBR membrane tank 1, and the output end of the drive pump 3 is connected to the external influent adsorber 12. The external influent adsorber 12 is connected to the hydrocyclone 6. The hydrocyclone 6 is nested inside the sludge thickening tank 4, and the bottom of the hydrocyclone 6 is connected to the sludge thickening tank 4. The activated sludge in the MBR membrane tank 1 is pumped by the drive pump 3 to the external feed water adsorber 12 for initial impurity removal. The resulting impurities are discharged. The resulting activated sludge mixture is pumped to the hydrocyclone separator 6 for primary impurity removal and concentration. The resulting upper mixture is returned to the MBR membrane tank 1, and the resulting lower mixture enters the sludge thickening tank 4 for secondary impurity removal and concentration. The resulting supernatant is returned to the MBR membrane tank 1, and the resulting lower mixture is discharged.

[0040] like Figure 6 As shown, the external inlet adsorber 12 includes a tank 120, an outlet pipe 125, a connecting pipe 121 with an inlet valve 122, and an bypass pipe 124 with a bypass valve 123. The side of the tank 120 is connected to the output end of the drive pump 3 via the connecting pipe 121, the top of the tank 120 is connected to the hydrocyclone 6 via the outlet pipe 125, and the bottom of the tank 120 is equipped with a sludge discharge branch pipe 126 with a sludge discharge valve 127. An electromagnet 11 is installed inside the tank 120. The inlet end of the bypass pipe 124 is connected in parallel with the connecting pipe 121, and the parallel connection is located at the front end of the inlet valve 122. The outlet end of the bypass pipe 124 is connected to the outlet pipe 125. This allows the activated sludge in the MBR membrane tank 1 to directly enter the hydrocyclone 6 via the bypass pipe 124 and the outlet pipe 125.

[0041] In this embodiment, the electromagnet 11, the inlet valve 122, the bypass valve 123, and the sludge discharge valve 127 are controlled in a coordinated manner. When the electromagnet 11 reaches the set adsorption time, the bypass valve 123 automatically opens, the inlet valve 122 automatically closes, and the sludge discharge valve 127 on the sludge discharge branch pipe 126 automatically opens. After sludge discharge is completed, the sludge discharge valve 127 automatically closes, the inlet valve 122 automatically opens, and the bypass valve 123 automatically closes.

[0042] In this embodiment, the working process of the impurity removal and sludge thickening system is as follows: S1: Drive pump 3 pumps the activated sludge from MBR membrane tank 1 into external feed water adsorber 12. Electromagnet 11 adsorbs iron filings from the activated sludge. After a set time, first open bypass valve 123 and close inlet valve 122. The activated sludge enters hydrocyclone separator 6 through bypass pipe 124 and outlet pipe 125. At this time, electromagnet 11 is de-energized, and iron filings enter the bottom of external feed water adsorber 12. Open sludge discharge valve 127 on sludge discharge branch pipe 126 to discharge the iron filings. Simultaneously, the activated sludge can be flushed through outlet pipe 125 to flush external feed water adsorber 12.

[0043] S2: After being adsorbed by the electromagnet 11, the activated sludge enters the hydrocyclone 6. Through hydrocyclone separation, the sand, calcium carbonate crystals, iron filings, and concentrated sludge in the activated sludge are discharged from the bottom sand outlet. This is the first concentration. The treated activated sludge returns to the MBR membrane tank 1 or enters the subsequent external MBR membrane through the overflow pipe 7 at the top of the hydrocyclone 6.

[0044] S3: Add flocculant to the settling nozzle 61 of the hydrocyclone 6 through the dosing pipe 8. Under the action of centrifugal force, the mixed sludge at the bottom of the hydrocyclone 6 is in a rotating state, mixing impurities, iron filings, concentrated sludge and flocculant. The mixed sludge enters the water distribution pipe 42 of the concentration tank 4.

[0045] S4: After the mixed sludge enters the distribution pipe 42 in the thickening tank 4, it is evenly distributed at the bottom of the thickening tank 4 for sedimentation. The concentrated sludge, impurities, and iron filings sink downwards after hitting the inclined plate 41, undergoing a second thickening. The supernatant flows out from the upper clear liquid pipe 9 after passing through the inclined plate 11, with an upward flow velocity of 5-9 m / h, and returns to the MBR membrane tank 1.

[0046] Example 3 The impurity removal and sludge thickening system of this invention was applied to an integrated MBR system in an industrial wastewater treatment plant with a daily processing capacity of 1200 m³. The plant's influent was mainly sludge filtrate, which, after biological treatment, entered the integrated MBR membrane tank for solid-liquid separation. Due to filter cloth damage, impurities such as iron filings, fine sand, and fibers entered the biological system, and calcium-containing wastewater formed calcium carbonate crystals within the biological system, resulting in a high content of inorganic impurities in the activated sludge in the membrane tank. The MLVSS / MLSS ratio was consistently below 0.5, and the ultrafiltration membrane was repeatedly damaged by scratches from hard particles.

[0047] To solve the above problems, the present invention provides a sludge removal and thickening system suitable for MBR processes. The main configuration of the system is as follows: Built-in inlet adsorber 2: Installed inside the MBR membrane tank 1, with a shell made of 316L stainless steel. The inlet hole 26 on the side wall of the outer baffle 25 has a diameter of 25mm. The rated adsorption force of the electromagnet 11 is 150kg. It is controlled by PLC and the adsorption cycle is set to 60 minutes (50 minutes of adsorption, followed by 10 minutes of cleaning after power failure). The stroke of the cylinder 21 is linked to the liquid level in the membrane tank, ensuring that the inner baffle 22 can still completely seal the inlet hole when the liquid level is at its lowest.

[0048] Hydrocyclone separator 6: It adopts a hydrocyclone, the inlet pipe flow velocity is controlled at 8m / s, and the design processing capacity is 40m³ / h.

[0049] Sludge thickening tank 4: The tank has a diameter of 2.5m and an effective height of 3m. It is equipped with a PP inclined plate 41 with an inclination angle of 60° inside. The bottom is conical, and the upward flow velocity is set to 8 m / h. The water distribution pipe 42 at the bottom is a ring-shaped perforated pipe.

[0050] Matching pumps, valves, and control system: The flow rate of drive pump 3 is 40 m³ / h, and the head is 15 m. All valves (sludge inlet, sludge outlet, bypass valve, etc.) are pneumatic valves, linked with the PLC system to achieve fully automatic operation.

[0051] Flocculant dosing system: PAC (polyaluminum chloride) is used as flocculant. The dosing point is located in the middle of the sedimentation nozzle 61 of the hydrocyclone separator. The dosing pump and the drive pump are linked to start and stop.

[0052] The system operates according to the following automated procedure: Impurity adsorption stage: The PLC starts and drives pump 3 and electromagnet 11. The aerated and agitated mixed liquid in the membrane tank flows through the inlet hole 26 of the outer baffle 25 of the adsorber, and magnetic impurities such as iron filings are adsorbed and trapped by electromagnet 11. This stage lasts for 50 minutes.

[0053] Impurity removal and cyclone separation stage: After the adsorption stage, the PLC controls the cylinder 21 to move, pushing the inner baffle 22 downward and sealing the water inlet hole 26 at the bottom of the outer baffle 25. At the same time, the electromagnet 11 is de-energized. The adsorbed iron filings fall off under the impact of the incoming water and are sucked in by the driven pump 3 along with some of the activated sludge, and sent into the cyclone separator 6 through the inlet pipe 5.

[0054] Primary Concentration and Flocculation: Inside the hydrocyclone separator 6, denser sand, calcium carbonate crystals, and concentrated sludge are discharged from the bottom settling nozzle 61 under centrifugal force, achieving the first stage of concentration. At the same time, PAC flocculant is continuously added to the outlet of the settling nozzle 61 through the dosing pipe 8, instantly mixing with the high-solids-content sludge flowing out of the hydrocyclone.

[0055] Secondary thickening and separation: Mixed sludge enters the water distribution pipe 42 at the bottom of the sludge thickening tank 4. Large particles and denser particles flow downwards into the conical hopper. Under the action of the inclined plate 41, the flocculated sludge particles settle rapidly, further thickening the sludge. The supernatant flows back to the MBR membrane tank 1 through the upper clear liquid pipe 9, while the thickened sludge accumulates at the bottom of the tank.

[0056] Sludge discharge and system recovery: The electric valve 101 on the sludge discharge pipe 10 at the bottom of the thickening tank 4 opens once every hour for 5 minutes each time to discharge concentrated sludge with a solids content of about 5%. After the sludge discharge is completed, the cylinder drives the inner baffle 22 to move upward, and the adsorber returns to the full-section water intake state to start the next cycle.

[0057] After 90 days of continuous and stable operation, the system achieved the following results: Impurity removal effect: Sludge samples from electromagnet 11 and sludge thickening tank 4 were periodically taken for analysis. Iron filings accounted for 82% of the adsorbate on electromagnet 11, with the remainder being coated sludge. Fine sand, fibers, and other impurities accounted for 12% of the total solids in the sludge discharged from sludge thickening tank 4, indicating that the system has a significant removal effect on both magnetic and non-magnetic hard impurities.

[0058] Improved sludge properties: The MLVSS / MLSS ratio of activated sludge in the MBR membrane tank increased from 0.48 before the modification to 0.65, and the organic components and biological activity of the activated sludge were significantly improved.

[0059] Concentration effect: Solid content was measured by sampling at each node of the system: the solid content of the sludge entering the hydrocyclone 6 was about 0.8%, and the solid content of its underflow (discharged from the sand settling nozzle 61) increased to 3.0%, with a flow rate of about 12% of the influent; after secondary concentration in the sludge thickening tank 4, the solid content of the discharged sludge stabilized at about 5.2%, and the volume was only 25% of the underflow of the hydrocyclone 6, achieving high-efficiency concentration.

[0060] Membrane protection effect: During operation, no more MBR membrane fiber damage incidents caused by scratches from hard particles occurred, and the online chemical cleaning cycle of the membrane module was extended from the original 15 days to more than 30 days.

[0061] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A sludge removal and thickening system suitable for MBR processes, characterized in that, It includes an MBR membrane tank (1), a drive pump (3), a sludge thickening tank (4), a hydrocyclone separator (6), and an inlet water adsorber, wherein the inlet water adsorber is equipped with an electromagnet (11). The influent adsorber is a built-in influent adsorber (2), which is installed inside the MBR membrane tank (1). The drive pump (3), sludge thickening tank (4), and hydrocyclone (6) are all installed outside the MBR membrane tank (1). The input end of the drive pump (3) is connected to the built-in influent adsorber (2), and the output end of the drive pump (3) is connected to the hydrocyclone (6). The hydrocyclone (6) is nested inside the sludge thickening tank (4). (6) The bottom is connected to the sludge thickening tank (4); the activated sludge in the MBR membrane tank (1) enters the built-in influent adsorber (2) for initial impurity removal and is then transported by the drive pump (3) to the hydrocyclone separator (6) to achieve primary impurity removal and concentration. The resulting upper mixed liquor is returned to the MBR membrane tank (1), and the resulting lower mixed liquor enters the sludge thickening tank (4) to achieve secondary impurity removal and concentration. The resulting supernatant is returned to the MBR membrane tank (1), and the resulting lower mixed liquor is discharged. Alternatively, the influent adsorber is an external influent adsorber (12). The external influent adsorber (12), drive pump (3), sludge thickening tank (4), and hydrocyclone (6) are all located outside the MBR membrane tank (1). The input end of the drive pump (3) is connected to the MBR membrane tank (1), and the output end of the drive pump (3) is connected to the external influent adsorber (12). The external influent adsorber (12) is connected to the hydrocyclone (6). The hydrocyclone (6) is nested inside the sludge thickening tank (4). The bottom of the hydrocyclone (6) The part is connected to the sludge thickening tank (4); the activated sludge in the MBR membrane tank (1) is transported to the external inlet water adsorber (12) by the drive pump (3) for the first impurity removal, the obtained impurities are discharged, the obtained activated sludge mixture is transported to the hydrocyclone separator (6) to achieve the first impurity removal and concentration, the obtained upper layer mixture is returned to the MBR membrane tank (1), the obtained lower layer mixture enters the sludge thickening tank (4) to achieve the second impurity removal and concentration, the obtained supernatant is returned to the MBR membrane tank (1), and the obtained lower layer mixture is discharged.

2. The sludge removal and thickening system for MBR processes according to claim 1, characterized in that, The built-in water inlet adsorber (2) includes an inner baffle (22), a support frame (24), an outer baffle (25), and a driving component; the electromagnet (11) is located inside the outer baffle (25), the support frame (24) is located on the top of the outer baffle (25), the driving component is installed on the support frame (24), and the output end of the driving component is connected to the inner baffle (22) to drive the inner baffle (22) to reciprocate up and down inside the outer baffle (25) to open or close the water inlet hole (26) on the side wall of the outer baffle (25).

3. The sludge removal and thickening system for MBR processes according to claim 2, characterized in that, The bottom of the outer baffle (25) is conical, and the bottom of the outer baffle (25) is connected to the drive pump (3) through the water inlet pipe (5).

4. The sludge removal and thickening system for MBR process according to claim 2, characterized in that, The driving component is a cylinder (21) or a motor.

5. The sludge removal and thickening system for MBR process according to claim 2, characterized in that, Limit sensors are provided on both the upper and lower parts of the inner baffle (22).

6. The sludge removal and thickening system for MBR process according to claim 1, characterized in that, The external water inlet adsorber (12) includes a tank (120), an outlet pipe (125), a connecting pipe (121) with an inlet valve (122), and an overpass pipe (124) with an overpass valve (123). The side of the tank (120) is connected to the output end of the drive pump (3) through the connecting pipe (121). The top of the tank (120) is connected to the hydrocyclone separator (6) through the outlet pipe (125). The bottom of the tank (120) is provided with a sludge discharge branch pipe (126) with a sludge discharge valve (127). An electromagnet (11) is provided inside the tank (120). The inlet end of the overpass pipe (124) is connected in parallel with the connecting pipe (121), and the parallel connection is located at the front end of the inlet valve (122). The outlet end of the overpass pipe (124) is connected to the outlet pipe (125).

7. The sludge removal and thickening system for MBR processes according to claim 6, characterized in that, The electromagnet (11), inlet valve (122), bypass valve (123) and sludge discharge valve (127) are linked for control. When the electromagnet (11) reaches the set adsorption time, the bypass valve (123) automatically opens, the inlet valve (122) automatically closes, and the sludge discharge valve (127) on the sludge discharge branch pipe (126) automatically opens. When the sludge discharge is completed, the sludge discharge valve (127) automatically closes, the inlet valve (122) automatically opens, and the bypass valve (123) automatically closes.

8. The sludge removal and thickening system for MBR processes according to any one of claims 1 to 7, characterized in that, The bottom of the cyclone separator (6) is provided with a sand settling nozzle (61), and the middle of the sand settling nozzle (61) is provided with a dosing port. The dosing port is connected to the dosing pipe (8) so as to realize the flocculant is added into the sand settling nozzle (61). The flocculant addition is linked to the drive pump (3) for control so as to open or close at the same time.

9. The sludge removal and thickening system for MBR process according to claim 8, characterized in that, The sludge thickening tank (4) has multiple inclined plates (41) in the middle and upper part along the vertical direction. The cyclone separator (6) is fixed in the sludge thickening tank (4) through the inclined plates (41). The sludge thickening tank (4) has a water distribution pipe (42) at the bottom and the sand settling nozzle (61) is connected to the water distribution pipe (42). The sludge thickening tank (4) has a sludge discharge pipe (10) at the bottom and a clear liquid pipe (9) on the side of the sludge thickening tank (4), and the clear liquid pipe (9) is located above the inclined plates (41).

10. The sludge removal and thickening system for MBR processes according to claim 8, characterized in that, The inlet flow rate of the cyclone separator (6) is controlled to be 5 m / s to 12 m / s.

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