A sludge dewatering device

Abstract

This utility model discloses an integrated sludge dewatering device, comprising: a sludge reaction tank for receiving and conditioning sludge generated from wastewater treatment, the tank being equipped with a stirrer and a sludge concentration meter; an iron salt flocculant feeding system for supplying iron salts to the sludge reaction tank; a hydrocyclone for receiving the iron salt-conditioned sludge and performing conditioning and primary concentration; the light outlet of the hydrocyclone is connected to the sludge reaction tank; a PAM flocculant feeding system for supplying PAM to the hydrocyclone; a conical thickener for receiving the flocculated sludge and performing secondary concentration; and an electrostatic dewatering device for receiving the secondary concentrated sludge and performing dewatering treatment. This dewatering device achieves efficient sludge dewatering by monitoring the sludge concentration before dewatering treatment and controlling the flocculant dosage; and by performing secondary concentration and electrostatic dewatering.

Description

Technical Field

[0001] This utility model relates to a sludge dewatering device, belonging to the field of sludge treatment technology. Background Technology

[0002] Wastewater treatment plants generate a large amount of excess sludge during the wastewater treatment process. The moisture content of this excess sludge is generally above 99%. After being concentrated in a sludge thickening tank, the moisture content of the sludge is generally 95-99%. Due to the high moisture content of the sludge, subsequent disposal is difficult, so further dewatering is necessary to reduce the moisture content of the sludge.

[0003] Common sludge dewatering methods include centrifugal dewatering, plate filter press, and belt filter press. These are all physical processes that utilize centrifugal force or pressure to separate the solid and liquid phases in sludge. Their core objective is to reduce sludge moisture content, thereby achieving volume reduction and economic efficiency in subsequent disposal (incineration, landfill, composting). Firstly, during sludge dewatering, flocculants (such as PAM and PAC) need to be added to the sludge to improve dewatering performance. However, sludge dewatering machines are continuously fed, and changes in sludge concentration cannot be immediately adjusted in the dosage, resulting in high moisture content in the dewatered sludge. Conversely, low sludge concentration leads to low dewatering efficiency. Furthermore, incomplete mixing of the chemicals in the pipeline, without sufficient reaction with the sludge, also results in high moisture content in the dewatered sludge. Secondly, conventional sludge dewatering machines typically only reduce sludge moisture content from 95%-99% to 60%-80%, indicating poor dewatering efficiency. Utility Model Content

[0004] The purpose of this invention is to provide an integrated sludge dewatering device that monitors the sludge concentration before dewatering and controls the amount of flocculant added; and achieves efficient sludge dewatering through secondary concentration and electro-dewatering.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A sludge dewatering device, comprising: The sludge reaction tank is used to receive and condition the sludge produced by wastewater treatment. The tank is equipped with a stirrer and a sludge concentration meter. The iron salt flocculant feeding system is connected to the sludge reaction tank and is used to supply iron salts into the sludge reaction tank. The hydrocyclone has its inlet connected to the sludge reaction tank and is used to receive sludge after iron salt conditioning and to condition and concentrate it at the first stage; the light outlet of the hydrocyclone is connected to the sludge reaction tank. The PAM flocculant feeding system is connected to the hydrocyclone and is used to supply PAM into the hydrocyclone. The conical thickener has its inlet connected to the heavy outlet of the hydrocyclone, and is used to receive flocculated sludge and perform secondary thickening. The electric dewatering device has its inlet connected to the sludge outlet of the conical thickener, and is used to receive the sludge after secondary thickening and dewater it.

[0006] Preferably, the iron salt flocculant feeding system includes an iron salt solvent tank and an iron salt transfer pump connected to the iron salt solvent tank pipeline. The outlet of the iron salt transfer pump is connected to the sludge reaction tank pipeline, and an iron salt flow meter is installed on the pipeline between the iron salt transfer pump and the sludge reaction tank.

[0007] Preferably, the PAM flocculant feeding system includes a PAM solvent tank and a PAM delivery pump connected to the PAM solvent tank pipeline. The outlet of the PAM delivery pump is connected to the inlet pipeline of the hydrocyclone. A PAM flow meter is installed on the pipeline between the PAM delivery pump and the hydrocyclone inlet.

[0008] Preferably, a cyclone feed pump is installed between the sludge reactor and the hydrocyclone. The inlet of the cyclone feed pump is connected to the bottom pipe of the sludge reactor, and the outlet is connected to the feed inlet pipe of the hydrocyclone.

[0009] Preferably, the sludge outlet of the cone thickener is connected to the feed inlet pipe of the electric dewatering device, and a dewatering pump for conveying the sludge after secondary thickening is installed on the pipe.

[0010] Preferably, the electro-dehydration device includes: An insulated dehydration tank has a feed inlet on the upper side and a drain outlet on the bottom side, with the drain outlet connected to a gas-liquid separator via a pipe. The microporous dehydration plate is horizontally mounted inside an insulated dehydration box located above the drain outlet; The anode plate and cathode plate are respectively embedded on the inner walls of the front and rear end walls of the insulating dehydration box located above the microporous dehydration plate, and are respectively connected to the positive and negative terminals of the external DC power supply. The lifting device is installed on the top plate of the insulated dewatering box and the actuating shaft extends vertically downward into the box. An insulated pressure plate is installed at the end of the actuating shaft, which fits against the inner wall of the insulated dewatering box and is used to filter the sludge. A vacuum pump, connected to the gas-liquid separator pipeline, is used to assist the water separated in the insulating dehydration tank in entering the gas-liquid separator. The door is hinged to one side wall of the insulating dehydration box and locked to the insulating dehydration box by a locking device. The door has an inner convex surface that is embedded in the opening on the side wall of the insulating dehydration box, and a sealing ring is wrapped around the outer edge of the inner convex surface. The bottom surface of the opening on the side wall of the insulating dehydration box is flush with the top surface of the microporous dehydration plate.

[0011] Preferably, a telescopic device is installed on the outside of the side wall of the insulated dehydration box on the side corresponding to the box door, and an insulated pusher plate with its bottom surface flush with the top surface of the microporous dehydration plate is embedded in the side wall on the same side. The actuating shaft of the telescopic device passes horizontally through the insulated dehydration box and is connected to the insulated pusher plate.

[0012] The beneficial effects of this utility model are as follows: Before sludge dewatering, a separate system is used to dosing and conditioning the sludge. This separate system allows for batch operation, enabling precise dosing based on sludge concentration. PAM flocculant is mixed with the sludge in a hydrocyclone, ensuring thorough and uniform mixing and initial concentration. The concentrated sludge then enters a conical thickener, where swirling occurs, further increasing floc size and achieving a second concentration, further enhancing sludge concentration. Finally, an electric field promotes sludge dewatering, and a pressure plate further filters the dewatered sludge, effectively improving the dewatering efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the connection of the sludge dewatering device; Figure 2 Schematic diagram of a cone-shaped concentrator; Figure 3 Schematic diagram of the electro-dehydration device (main section); Figure 4 This is a schematic diagram (side section) of the anode plate and cathode plate inside the insulated dehydration tank.

[0014] The meanings of the main reference numerals in the figure are as follows: 1. Sludge reaction tank; 2. Iron salt flocculant feeding system; 3. Hydrocyclone; 4. PAM flocculant feeding system; 5. Conical thickener; 6. Electrostatic dewatering device; 7. Agitator; 8. Sludge concentration meter; 9. Iron salt solvent tank; 10. Iron salt transfer pump; 11. Iron salt flow meter; 12. Hydrocyclone feed pump; 13. PAM solvent tank; 14. PAM transfer pump; 15. PAM flow meter; 16. Tangential pipe; 17. 18. Dehydration pump, 29. Clear liquid collection tank, 20. Drain pipe, 21. Insulated dehydration box, 22. Feed inlet, 23. Drain outlet, 24. Cable, 25. Gas-liquid separator, 26. Microporous dehydration plate, 27. Anode plate, 28. Cathode plate, 29. Vacuum pump, 30. Lifting device, 31. Insulated pressure plate, 32. Box door, 33. Inner convex surface, 34. Sealing ring, 35. Telescopic device, 36. Insulated pusher plate. Detailed Implementation

[0015] This embodiment provides a sludge dewatering device, such as Figure 1-4As shown, the system includes a sludge reaction tank 1, an iron salt flocculant feeding system 2, a hydrocyclone 3, a PAM flocculant feeding system 4, a conical thickener 5, and an electrostatic dewatering device 6 (in practical applications, valves for flow control can be installed on the pipelines connecting the various components according to actual needs). The sludge reaction tank 1 receives sludge generated after wastewater treatment. It contains a stirrer 7 and a sludge concentration meter 8. The stirrer 7 mixes the sludge evenly, and then, based on the data measured by the sludge concentration meter 8, the iron salt solvent is pumped into the sludge reaction tank 1 through the iron salt flocculant feeding system 2. Specifically, the iron salt flocculant feeding system 2 includes an iron salt solvent tank 9 and an iron salt transfer pump 10 connected to the iron salt solvent tank 9 via a pipeline. The outlet of the iron salt transfer pump 10 is connected to the pipeline of the sludge reaction tank 1, and an iron salt flow meter 11 is installed on the pipeline between the iron salt transfer pump 10 and the sludge reaction tank 1. The iron salt solvent is precisely delivered by the iron salt transfer pump 10 and the iron salt flow meter 11. Then, under the stirring action of the stirrer 7, the iron salt reacts with the sludge in the reaction tank.

[0016] A cyclone feed pump 12 is installed between the sludge reaction tank 1 and the hydrocyclone 3. The inlet of the cyclone feed pump 12 is connected to the bottom pipe of the sludge reaction tank 1, and the outlet is connected to the inlet 21 pipe of the hydrocyclone 3. The sludge conditioned with iron salt is pumped into the hydrocyclone 3 by the cyclone feed pump 12. The concentration of the sludge after iron salt conditioning can also be measured by the sludge concentration meter 8 in the sludge reaction tank 1. Then, PAM is pumped into the hydrocyclone 3 through the PAM flocculant supply system 4. Specifically, the PAM flocculant supply system 4 includes a PAM solvent tank 13 and a PAM transfer pump 14 connected to the PAM solvent tank 13 by a pipe. The outlet of the PAM transfer pump 14 is connected to the inlet 21 pipe of the hydrocyclone 3, and a PAM flow meter 15 is installed on the pipe between the PAM transfer pump 14 and the inlet 21 of the hydrocyclone 3. Through the delivery of PAM by the PAM transfer pump 14 and the measurement of PAM flow meter 15, accurate delivery of PAM is achieved. Then, under the action of hydrocyclone 3, PAM and sludge are fully mixed and concentrated in one step. The concentrated sludge enters the conical thickener 5 tangentially from the lower outlet through the tangential pipe 16, while the unflocculated light sludge returns to the sludge reaction tank 1 from the upper outlet.

[0017] The sludge entering the conical thickener 5 tangentially generates swirling flow within it, further increasing the size of the flocs and undergoing secondary concentration at the bottom. The sludge outlet of the conical thickener 5 is connected to the inlet 21 of the electrostatic dewatering device 6, and a dewatering pump 17 for conveying the secondary-concentrated sludge is installed on the pipe. The secondary-concentrated sludge is pumped into the electrostatic dewatering device 6 through the bottom pipe by the dewatering pump 17 for dewatering. The supernatant in the conical thickener 5 overflows into the supernatant collection tank 18 under the action of swirling flow and is discharged from the drain pipe 19.

[0018] The electrostatic dehydration device 6 includes an insulated dehydration tank 20, with an inlet 21 on one side and a drain outlet 22 on the bottom of the other side. The drain outlet 22 is connected to a gas-liquid separator 24 via a pipe. The gas-liquid separator 24 is installed at a lower height than the insulated dehydration tank 20 so that the dehydrated water can flow into the gas-liquid separator 24 for separation. A microporous dehydration plate 25 (250 mesh vertical micropores) is horizontally mounted inside the insulated dehydration tank 20 above the drain outlet 22. An anode plate 26 and a cathode plate 27 are embedded in corresponding grooves on the inner walls of the front and rear end walls of the insulated dehydration tank 20 above the microporous dehydration plate 25 (the outer surfaces of both are flush with the inner side walls of the insulated dehydration tank 20 and are sealed between them). The anode plate 26 and the cathode plate 27 (which can be titanium-based ruthenium-iridium plates) are connected to the positive and negative terminals of an external DC power supply via cables 23 that pass through the tank. A vacuum pump 28 is connected to the gas-liquid separator 24 via a pipeline to assist the water separated in the insulated dehydration tank 20 in entering the gas-liquid separator 24. Simultaneously, a lifting device 29 with an actuator shaft extending vertically downwards into the tank is installed on the top plate of the insulated dehydration tank 20. An insulating pressure plate 30, which conforms to the inner wall of the insulated dehydration tank 20, is installed at the end of the actuator shaft of the lifting device 29 for compressing the sludge.

[0019] After secondary concentration, the sludge enters the insulated dewatering tank 20 under the intermittent transport of the dewatering pump 17. In practical applications, a sludge flow meter is installed on the pipeline between the dewatering pump 17 and the insulated dewatering tank 20 to achieve quantitative sludge transport and facilitate subsequent control of the electric field strength between the anode plate 26 and the cathode plate 27. The sludge entering the insulated dewatering tank 20, under the influence of high water content and gravity, will level out and come into contact with the anode plate 26 and the cathode plate 27. At this time, the anode plate 26, the sludge, the cathode plate 27, and the DC power supply can form a current loop. A stable current is then output to the anode plate 26 through the DC power supply (pulse switch adjustable DC power supply), thereby forming a stable electric field in the sludge (electric field strength controlled between 3-8V / mm) for electro-osmotic dewatering treatment. The dewatered water will fall to the bottom of the insulated dewatering tank 20 through the microporous dewatering plate 25.

[0020] After electro-osmotic dewatering of the sludge, the DC power supply is stopped. Then, the lifting device 29 is activated to drive the insulating pressure plate 30 to press down on the dewatered sludge, promoting further dewatering and pressing the sludge into a sludge cake. At the same time, the vacuum pump 28 is activated, using the suction force to quickly and effectively pump the liquid collected at the bottom of the insulating dewatering tank 20 into the gas-liquid separator 24 to achieve gas-liquid separation (in practical applications, a cooling water pipe can be installed outside the gas-liquid separator 24 to improve the liquid collection efficiency, and a pressure regulating pipe, i.e., a short connecting pipe with a valve, can be installed on the gas-liquid separator 24).

[0021] To facilitate the removal of the filter cake, a door 31 is hinged to one side wall of the insulated dewatering tank 20. The door 31 is locked to the insulated dewatering tank 20 by a locking device, and the door has an inner convex surface 32 that is embedded in the opening on the side wall of the insulated dewatering tank 20. A sealing ring 33 is wrapped around the outer edge of the inner convex surface 32. The bottom surface of the opening on the side wall of the insulated dewatering tank 20 is flush with the top surface of the microporous dewatering plate 25. At the same time, a telescopic device 34 is installed on the outside of the side wall of the insulated dewatering tank 20 on the side corresponding to the door 31. An insulated pusher plate 35 with its bottom surface flush with the top surface of the microporous dewatering plate 25 is embedded in the side wall on the same side. The actuating shaft of the telescopic device 34 passes horizontally through the insulated dewatering tank 20 and is connected to the insulated pusher plate 35. After the sludge is pressed into a cake, the chamber door 31 is opened, and then the telescopic device 34 is activated to move the cake toward the chamber door 31. The cake can then be removed from the chamber door 31. The moisture content of the dewatered cake is between 30% and 40%, which is much lower than the moisture content of conventionally dewatered sludge (60%-80%).

[0022] The devices, components, or connections between components not detailed in this embodiment are all existing mature technologies and will not be elaborated here.

[0023] The above description is only a preferred embodiment of this utility model patent. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model patent, and these improvements and modifications should also be considered within the scope of protection of this utility model patent.

Claims

1. A sludge dewatering apparatus, characterized by, include: The sludge reaction tank is used to receive and condition the sludge produced by wastewater treatment. The tank is equipped with a stirrer and a sludge concentration meter. The iron salt flocculant feeding system is connected to the sludge reaction tank and is used to supply iron salts into the sludge reaction tank. The hydrocyclone has its inlet connected to the sludge reaction tank and is used to receive sludge after iron salt conditioning and to condition and concentrate it at the first stage; the light outlet of the hydrocyclone is connected to the sludge reaction tank. The PAM flocculant feeding system is connected to the hydrocyclone and is used to supply PAM into the hydrocyclone. The conical thickener has its inlet connected to the heavy outlet of the hydrocyclone, and is used to receive flocculated sludge and perform secondary thickening. The electric dewatering device has its inlet connected to the sludge outlet of the conical thickener, and is used to receive the sludge after secondary thickening and dewater it.

2. The sludge dewatering device according to claim 1, characterized in that The iron salt flocculant feeding system includes an iron salt solvent tank and an iron salt transfer pump connected to the iron salt solvent tank pipeline. The outlet of the iron salt transfer pump is connected to the sludge reaction tank pipeline. An iron salt flow meter is installed on the pipeline between the iron salt transfer pump and the sludge reaction tank.

3. The sludge dewatering device according to claim 1, characterized in that, The PAM flocculant feeding system includes a PAM solvent tank and a PAM delivery pump connected to the PAM solvent tank via a pipeline. The outlet of the PAM delivery pump is connected to the inlet pipeline of the hydrocyclone. A PAM flow meter is installed on the pipeline between the PAM delivery pump and the inlet of the hydrocyclone.

4. The sludge dewatering device according to claim 1, characterized by A cyclone feed pump is installed between the sludge reactor and the hydrocyclone. The inlet of the cyclone feed pump is connected to the bottom pipe of the sludge reactor, and the outlet is connected to the feed inlet pipe of the hydrocyclone.

5. The sludge dewatering device of claim 1, wherein The sludge outlet of the cone thickener is connected to the feed inlet pipe of the electric dewatering unit, and a dewatering pump for conveying the sludge after secondary thickening is installed on the pipe.

6. The sludge dewatering device according to claim 1, characterized in that, The electro-dehydration device includes: An insulated dehydration tank has a feed inlet on the upper side and a drain outlet on the bottom side, with the drain outlet connected to a gas-liquid separator via a pipe. The microporous dehydration plate is horizontally mounted inside an insulated dehydration box located above the drain outlet; The anode plate and cathode plate are respectively embedded on the inner walls of the front and rear end walls of the insulating dehydration box located above the microporous dehydration plate, and are respectively connected to the positive and negative terminals of the external DC power supply. The lifting device is installed on the top plate of the insulated dewatering box and the actuating shaft extends vertically downward into the box. An insulated pressure plate is installed at the end of the actuating shaft, which fits against the inner wall of the insulated dewatering box and is used to filter the sludge. A vacuum pump, connected to the gas-liquid separator pipeline, is used to assist the water separated in the insulating dehydration tank in entering the gas-liquid separator. The door is hinged to one side wall of the insulating dehydration box and locked to the insulating dehydration box by a locking device. The door has an inner convex surface that is embedded in the opening on the side wall of the insulating dehydration box, and a sealing ring is wrapped around the outer edge of the inner convex surface. The bottom surface of the opening on the side wall of the insulating dehydration box is flush with the top surface of the microporous dehydration plate.

7. The sludge dewatering apparatus of claim 6, wherein A telescopic device is installed on the outside of the side wall of the insulated dehydration box on the side corresponding to the box door. An insulated pusher plate with its bottom surface flush with the top surface of the microporous dehydration plate is embedded in the side wall on the same side. The actuating shaft of the telescopic device passes horizontally through the insulated dehydration box and is connected to the insulated pusher plate.

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