Precipitation, concentration and dehydration integrated equipment suitable for superfine particles in river and lake polluted bottom mud

Abstract

The invention belongs to the technical field of ecological restoration of river and lake water, and discloses integrated equipment suitable for precipitation, concentration and dehydration of superfine particles of river and lake polluted bottom mud, which comprises an efficient coprecipitation unit, a multi-layer radial-flow sludge concentration unit, a water inlet pipe, a water outlet pipe and a water outlet pipe, the discharge end of the multi-layer radial-flow sludge concentration unit is connected with a stacked screw dewatering unit, the outer side of the efficient co-precipitation unit is connected with an electric control box, the efficient co-precipitation unit comprises a medicine dispensing and feeding box placed at the front end of a precipitation tank, and a three-grid coagulation and flocculation tank is arranged in the medicine dispensing and feeding box; aiming at the low turbidity characteristic of sewage after bottom mud elution and the coexistence problem of fine particles and algae, an efficient coprecipitation process is provided, a PAC / PAM / fly ash three-agent collaborative adding system is designed, a sludge backflow dynamic regulation and control mechanism is combined, the floc core density is enhanced through fly ash coprecipitation, and the floc settling speed is remarkably increased.

Description

Technical Field

[0001] This invention belongs to the field of river and lake water ecological restoration technology, and in particular relates to an integrated device for sedimentation, concentration and dewatering of extremely fine particles of polluted sediment in rivers and lakes. Background Technology

[0002] At present, polluted sediment in rivers and lakes is the main endogenous source of water quality deterioration. Although traditional dredging techniques (such as mechanical excavation and pumping and transportation) can quickly remove polluted sediment, they have the following problems: (1) Large-scale sediment dredging destroys the matrix stabilization layer, causing sediment to be resuspended, accelerating the release of pollutants such as nitrogen and phosphorus, which in turn exacerbates eutrophication of water bodies; (2) The amount of sediment transported for disposal is huge, the landfill cost is high, and there is a risk of secondary pollution during the transportation process. Currently, sediment washing technology is a water ecological restoration technology that precisely removes polluted floating sludge and forms a clean surface cover. It can quickly clarify water bodies and provide a good habitat for the restoration of submerged plant communities. However, the sediment that comes ashore after sediment washing generally has a high water content (greater than 98%), extremely small inorganic particle size (less than 75μm), and contains algae that produce gas bubbles. Using the traditional "coagulation-sedimentation" process, the effluent has low transparency (turbidity greater than 15NTU), the equipment occupies a large area, and the sludge has a high water content after dewatering. Due to the floating of algae and the difficulty of particle settling, the effluent from the sewage sedimentation tank has high turbidity and floating sludge on the surface, which affects the water quality of the effluent from the sediment washing process. Currently, most high-efficiency wastewater sedimentation tanks on the market are based on the "shallow sedimentation" theory, increasing the sedimentation area, shortening sludge retention time, and reducing the footprint through the application of inclined tubes / plates. However, these systems lack a sludge return system and have limited capacity to retain fine particles (<50μm) and algae, resulting in effluent turbidity typically >10 NTU (turbidity). In contrast, high-density sedimentation tanks used in wastewater treatment incorporate a sludge return system, returning 10%–20% of concentrated sludge to the reaction zone to form high-concentration flocs (MLSS (mixed liquor suspended solids) reaching 15–30 g / L), significantly increasing floc density and settling velocity. However, these systems are only suitable for purifying water sources with medium to high turbidity and high algae levels. Therefore, they lack stable, reliable, and economical high-standard effluent for low-turbidity wastewater generated after sludge washing. Summary of the Invention

[0003] This invention addresses the shortcomings of existing wastewater high-efficiency sedimentation tanks, which are based on the "shallow sedimentation" theory and utilize inclined tubes / plates to increase sedimentation area, shorten sludge retention time, and reduce floor space. However, these systems lack a sludge return system and have limited capacity to retain fine particles (<50μm) and algae, resulting in effluent turbidity typically >10 NTU. In contrast, high-density wastewater sedimentation tanks incorporate a sludge return system, returning 10%–20% of concentrated sludge to the reaction zone to form high-concentration flocs (MLSS reaching 15–30 g / L), significantly increasing floc density and settling velocity. However, these systems are only suitable for purifying water sources with medium to high turbidity and high algae levels. Therefore, to address the lack of stable, reliable, and economical high-standard effluent technology and equipment for low-turbidity wastewater generated after sludge washing, the following technical solution is proposed: An integrated equipment for sedimentation, concentration and dewatering of extremely fine particles of polluted sediment in rivers and lakes includes a high-efficiency co-sedimentation unit. The discharge end of the high-efficiency co-sedimentation unit is connected to a multi-layer radial flow sludge thickening unit. The discharge end of the multi-layer radial flow sludge thickening unit is connected to a screw press dewatering unit. An electrical control box is connected to the outside of the high-efficiency co-sedimentation unit. The high-efficiency co-precipitation unit includes a dosing tank placed on the ground. Inside the dosing tank is a three-compartment coagulation and flocculation tank. A PAC reagent tank is installed inside the dosing tank on one side of the three-compartment coagulation and flocculation tank. A PAM reagent tank is installed inside the dosing tank on one side of the PAC reagent tank. A fly ash reagent tank is installed inside the dosing tank on one side of the PAM reagent tank. A sludge return pump is installed at the bottom of the dosing tank. A clean water return pump is installed inside the dosing tank.

[0004] As a preferred embodiment of the above technical solution, agitators are installed at the top of the dosing tank, inside the PAC, PAM, and fly ash reagent tanks, and at the three-compartment coagulation and flocculation tank. A water inlet pipe is symmetrically embedded at the top of the three-compartment coagulation and flocculation tank on one end face of the dosing tank, and a drain pipe is symmetrically embedded at the bottom of the three-compartment coagulation and flocculation tank on one end face of the dosing tank. A plunger-type metering pump is installed above the dosing tank, on one side of the agitator at the top of the PAC, PAM, and fly ash reagent tanks. The inlet ends of the three plunger-type metering pumps are located inside the PAC, PAM, and fly ash reagent tanks, respectively, and the outlet ends of the three plunger-type metering pumps are located inside the three-compartment coagulation and flocculation tank, respectively.

[0005] As a preferred embodiment of the above technical solution, the dosing tank is equipped with a water distribution compartment at the outlet end of the three-compartment coagulation and flocculation tank. A sewage sedimentation tank is installed at the outlet end of the water distribution compartment inside the dosing tank. A flow guide chamber is installed inside the sewage sedimentation tank. The number of sewage sedimentation tanks and flow guide chambers is set to three. Inclined tube supports are installed inside each of the three sewage sedimentation tanks. An inclined tube assembly is installed at one end of the inclined tube support. A clear water chamber is set at one end of the flow guide chamber inside the dosing tank. A clear water return pump is installed at the bottom of the inner wall of the clear water chamber.

[0006] As a preferred embodiment of the above technical solution, each of the three wastewater sedimentation tanks is connected to a continuous sludge hopper at its bottom. A fixed support is installed on the outside of the dosing and mixing tank located on the outside of the three wastewater sedimentation tanks. The bottom ends of the three continuous sludge hoppers are connected to the same sludge return pump via pipes. The discharge end of the sludge return pump is connected to the inside of the three-compartment coagulation and flocculation tank via pipes. A storage tank is installed inside the dosing and mixing tank at the bottom of the PAC agent tank. A suspended ladder is installed on the outside of the dosing and mixing tank at one end of the storage tank.

[0007] As a preferred embodiment of the above technical solution, the multi-layer radial flow sludge thickening unit includes a sludge inlet pump connected to the bottom pipes of the three continuous sludge hoppers. The discharge end of the sludge inlet pump is connected to a radial flow sludge settling assembly via a pipe. A sludge storage hopper is fitted on the outside of the pipe connecting the discharge end of the sludge inlet pump to the radial flow sludge settling assembly. A sludge discharge pipe is embedded at the bottom of the sludge storage hopper. A vertical outer wall is connected to the top of the sludge storage hopper. A clear water overflow tank is connected to the top of the vertical outer wall. A clear water drain pipe is embedded at the bottom of the clear water overflow tank.

[0008] As a preferred embodiment of the above technical solution, the radial flow sludge settling assembly includes a sludge-water mixture inlet pipe connected to the outlet pipe of the sludge pump. Sludge-water mixture dispersion pipes are symmetrically arranged at equal intervals on the outer surface of the sludge-water mixture inlet pipe. The sludge-water mixture dispersion pipes are configured in four groups. Each group of sludge-water mixture dispersion pipes is symmetrically distributed at equal intervals around the center point of the sludge-water mixture inlet pipe, and four such pipes are arranged. A sludge guide pipe is sleeved on the outside of each group of sludge-water mixture dispersion pipes. A funnel sedimentation tank is welded to the top of the sludge guide pipe. A water equalization guide plate is welded to the outside of the sludge guide pipe. The outlet of the sludge-water mixture dispersion pipe is located between the inner wall of the water equalization guide plate and the outside of the sludge guide pipe.

[0009] As a preferred embodiment of the above technical solution, the screw press dewatering unit includes a sludge inlet pipe connected to a sludge discharge pipe. A dosing and mixing tank is connected to the top of the sludge inlet pipe. A mixing and stirring structure is fixedly installed at the top of the dosing and mixing tank. A fixed flocculation tank is provided on one side of the dosing and mixing tank. A mechanical dewatering tank is provided on one side of the fixed flocculation tank. A stacked plate assembly is installed inside the mechanical dewatering tank. A drive motor is installed at one end of the mechanical dewatering tank.

[0010] As a preferred embodiment of the above technical solution, the output shaft of the drive motor is connected to the laminated plate assembly, the bottom ends of the fixed flocculation tank and the mechanical dewatering tank are connected to the same bracket, a sludge outlet pipe is embedded on one side of the bottom end of the mechanical dewatering tank, and a tailwater outlet pipe is installed at one end of the mechanical dewatering tank located below the drive motor.

[0011] As a preferred embodiment of the above technical solution, a control box is fixedly installed on the front of the fixed flocculation tank, and the drive motor is composed of a motor and a reducer. The rotating shaft of the reducer is connected to the laminated plate group by a flat key, and the bottom end of the support is in contact with the ground.

[0012] The beneficial effects of this invention are as follows: (1) To address the challenges of low turbidity (MLSS≤1g / L) and coexistence of fine particles (<50μm) and algae in the wastewater after sludge washing, a highly efficient co-precipitation process was proposed. A three-agent synergistic dosing system of "PAC / PAM / fly ash" was designed, combined with a sludge return dynamic control mechanism (return ratio 0.1–0.5). Fly ash co-precipitation enhanced the floc density (dosage 0–8g / L), significantly improving the floc settling velocity (40% faster than the traditional process). (2) The multi-layer radial flow sedimentation component expands the sedimentation area by 3 times through the three-dimensional superimposed inclined plate slope structure, shortens the sludge retention time to 4 hours (the traditional process requires 8-12 hours), reduces the equipment footprint by 50%, and increases the sludge thickening efficiency by 200%. It is suitable for small spaces (such as vehicle-mounted mobile scenarios) and provides ideal feeding conditions for the subsequent screw press dewatering unit. (3) This invention realizes modular integration and intelligent linkage control of the whole process. It is the first to create a three-module vehicle-mounted integrated system of "high-efficiency co-precipitation - radial flow concentration - mechanical dewatering". The high-efficiency co-precipitation unit realizes intelligent linkage of reagent addition and sludge return; the multi-layer radial flow sludge concentration unit realizes a compact three-dimensional structure; and the screw press dewatering unit realizes deep dewatering, reducing the moisture content to below 60%. Attached Figure Description

[0013] Figure 1 The diagram shown is a schematic diagram of an integrated equipment for sedimentation, concentration and dewatering of extremely fine particles of polluted sediment in rivers and lakes, as described in Example 1. Figure 2The diagram shown is a schematic diagram of the high-efficiency coprecipitation unit in Example 1; Figure 3 The diagram shown is a schematic diagram of the structure of the multi-layer radial flow sludge thickening unit in Example 1; Figure 4 The diagram shown is a cross-sectional view of the multi-layer radial flow sludge thickening unit in Example 1; Figure 5 The diagram shown is a cross-sectional view of the radial flow sludge settling assembly in Example 1; Figure 6 The diagram shown is a structural schematic of the screw press dewatering unit in Example 1; Figure 7 The diagram shown is a schematic of the effluent quality under the high-concentration sludge treatment mode in Example 1; Figure 8 The diagram shown is a schematic of the effluent quality under the medium-concentration sludge treatment mode in Example 1; Figure 9 The diagram shown is a schematic of the effluent quality under the low-concentration sludge treatment mode in Example 1; Figure 10 The diagram shows the sludge moisture content of the multi-layer radial flow sludge thickening unit under the low-concentration sludge treatment mode in Example 1.

[0014] In the diagram: 1. High-efficiency co-precipitation unit; 11. Dosing tank; 12. Inlet pipe; 13. PAC reagent tank; 14. PAM reagent tank; 15. Fly ash reagent tank; 16. Agitator; 17. Plunger metering pump; 18. Three-compartment coagulation and flocculation tank; 19. Water distribution compartment; 110. Wastewater sedimentation tank; 111. Flow guide chamber; 112. Inclined tube assembly; 113. Inclined tube support; 114. Clear water chamber; 115. Clear water return pump; 116. Continuous sludge hopper; 117. Fixed support; 118. Sludge return pump; 119. Drain pipe; 120. Chemical storage tank; 121. Suspended ladder; 2. Multi-layer radial flow sludge thickening unit; 21. Sludge inlet pump; 22. Sludge storage hopper; 23. Radial flow sludge settling assembly; 24. Clear water overflow tank; 25. Clear water drain pipe; 26. Sludge discharge pipe; 27. Vertical outer wall; 28. Sludge-water mixture inlet pipe; 29. ​​Sludge-water mixture dispersion pipe; 210. Water distribution guide plate; 211. Sludge guide pipe; 212. Funnel sedimentation tank; 3. Screw press dewatering unit; 31. Sludge inlet pipe; 32. Dosing and mixing tank; 33. Mixing and stirring structure; 34. Fixed flocculation tank; 35. Mechanical dewatering tank; 36. Disc assembly; 37. Drive motor; 38. Control box; 39. Support frame; 310. Sludge outlet pipe; 311. Tailwater outlet pipe; 4. Electrical control box. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0016] Example 1 This invention provides an integrated device for sedimentation, concentration, and dewatering of extremely fine particles in polluted river and lake sediments, such as... Figures 1 to 10 As shown, it includes: a high-efficiency co-precipitation unit 1, a multi-layer radial flow sludge thickening unit 2, a screw press dewatering unit 3, and an electrical control box 4; each unit is connected in sequence through pipelines: the discharge end of the high-efficiency co-precipitation unit 1 is connected to the multi-layer radial flow sludge thickening unit 2, the discharge end of the multi-layer radial flow sludge thickening unit 2 is connected to the screw press dewatering unit 3, the high-efficiency co-precipitation unit 1 coagulates and settles the bottom sludge-water mixture, the resulting preliminary thickened sludge is transported to the multi-layer radial flow sludge thickening unit 2 for further thickening and volume reduction, and finally the thickened sludge enters the screw press dewatering unit 3 to achieve solid-liquid separation, the electrical control box 4 is installed on the outside of the high-efficiency co-precipitation unit 1, and is used to control the operating parameters of each unit in a unified manner; The high-efficiency co-precipitation unit 1 includes a dosing tank 11 placed on the ground. The dosing tank 11 integrates a three-compartment coagulation and flocculation tank 18, which serves as the core reaction zone. A PAC (polyaluminum chloride) reagent tank 13 (for storing polyaluminum chloride) is installed inside the dosing tank 11 on one side of the three-compartment coagulation and flocculation tank 18. A PAM (polyacrylamide) reagent tank 14 (for storing polyacrylamide) is installed inside the dosing tank 11 on one side of the PAC reagent tank 13. A fly ash reagent tank 15 (for storing fly ash, an auxiliary flocculant) is installed inside the dosing tank 11 on one side of the PAM reagent tank 14. A sludge return pump 118 is installed at the bottom of the dosing tank 11. A clean water return pump 115 is installed inside the dosing tank 11.

[0017] like Figure 1 and Figure 2As shown, agitators 16 (composed of a motor and a stirring rod) are installed at the top of the dosing tank 11, inside the PAC reagent tank 13, PAM reagent tank 14, fly ash reagent tank 15, and the three-compartment coagulation and flocculation tank 18. The agitators 16 ensure uniform reagent concentration in the PAC reagent tank 13, PAM reagent tank 14, and fly ash reagent tank 15 (avoiding reagent sedimentation and stratification), and ensure thorough mixing of the sludge and reagents in the three-compartment coagulation and flocculation tank 18 (improving mixing uniformity). A water inlet pipe 12 is symmetrically embedded at one end of the dosing tank 11, located at the top of the three-compartment coagulation and flocculation tank 18. The symmetrically arranged water inlet pipes 12 ensure uniform entry of the sludge and water into the reaction tank. A drain pipe 119 is symmetrically embedded at the bottom of the coagulation and flocculation tank 18. The drain pipe 119 facilitates cleaning and maintenance after equipment shutdown and reduces the risk of residual sludge clumping. A plunger metering pump 17 is installed on one side of the agitator 16 at the top of the PAC reagent tank 13, PAM reagent tank 14, and fly ash reagent tank 15 above the dosing tank 11. The plunger metering pump 17 enables precise dosing of reagents (reducing dosing error) and can adjust the dosage according to the bottom sludge concentration to avoid reagent waste. The inlet ends of the three plunger metering pumps 17 are located inside the PAC reagent tank 13, PAM reagent tank 14, and fly ash reagent tank 15, respectively, and the outlet ends of the three plunger metering pumps 17 are located inside the three-compartment coagulation and flocculation tank 18.

[0018] like Figure 1 and Figure 2 As shown, a water distribution compartment 19 is located inside the dosing tank 11 at the outlet end of the three-compartment coagulation and flocculation tank 18. The water distribution compartment 19 allows the flocculated sludge to flow to the sewage sedimentation tank 110. The sewage sedimentation tank 110 is installed inside the dosing tank 11 at the outlet end of the water distribution compartment 19. The sewage sedimentation tank 110 is equipped with a flow guide chamber 111. There are three sewage sedimentation tanks 110 and three flow guide chambers 111. Inclined tubes are installed inside each of the three sewage sedimentation tanks 110. The support 113 has an inclined tube assembly 112 (using a 60° inclined honeycomb inclined tube) installed at one end. The inclined tube assembly 112 increases the sedimentation area, shortens the sedimentation path of ultrafine particles, and improves sedimentation efficiency. Inside the dosing tank 11, a clear water chamber 114 is set at one end of the flow guide chamber 111. A clear water return pump 115 is installed at the bottom of the inner wall of the clear water chamber 114. The supernatant collected in the clear water chamber 114 is discharged from the equipment through the clear water return pump 115, realizing the recycling of water resources.

[0019] like Figure 1 and Figure 2As shown, each of the three wastewater sedimentation tanks 110 is connected to a continuous sludge hopper 116 (the continuous sludge hopper 116 adopts a conical design) at its bottom to prevent sludge accumulation and blockage, ensuring continuous sludge discharge. A fixed support 117 is installed on the outside of the dosing tank 11, located on the outside of the three wastewater sedimentation tanks 110. The bottom ends of the three continuous sludge hoppers 116 are connected to the inlet of the same sludge return pump 118 via pipes. The discharge end of the sludge return pump 118 is connected to the inside of the three-compartment coagulation and flocculation tank 18 via a pipe. Part of the settled sludge is returned to the three-compartment coagulation and flocculation tank 18. The returned sludge adds a "gravity core" to the three-compartment coagulation and flocculation tank 18, thereby improving the flocculation effect and sedimentation efficiency. Inside the dosing and dispensing tank 11, at the bottom of the PAC agent tank 13, there is a storage tank 120. The storage tank 120 increases the agent reserve for easy replenishment. On the outside of the dosing and dispensing tank 11, at one end of the storage tank 120, a suspended ladder 121 is installed. The suspended ladder 121 facilitates the operator to inspect and maintain the equipment at the top of the dosing and dispensing tank 11, improving operational safety.

[0020] like Figures 3 to 5 As shown, the multi-layer radial flow sludge thickening unit 2 includes a sludge inlet pump 21 connected to the bottom pipes of three continuous sludge hoppers 116. The sludge inlet pump 21 achieves stable sludge transport and prevents sludge from settling in the pipes. The discharge end of the sludge inlet pump 21 is connected to a radial flow sludge settling assembly 23 via a pipe. A sludge storage hopper 22 is fitted on the outside of the pipe connecting the discharge end of the sludge inlet pump 21 to the radial flow sludge settling assembly 23. The sludge storage hopper 22 is used to store the sludge discharged from the sludge inlet pump 21. A sludge discharge pipe 26 is embedded at the bottom of the hopper 22. A vertical outer wall 27 is connected to the top of the sludge storage hopper 22. The vertical outer wall 27 is composed of a protective cover and a support arm, wherein the support arm is in contact with the ground. A clear water overflow tank 24 is connected to the top of the vertical outer wall 27. A clear water drain pipe 25 is embedded at the bottom of the clear water overflow tank 24. The clear water overflow tank 24 collects the supernatant separated during the concentration process and discharges or reuses it through the clear water drain pipe 25, thereby achieving preliminary water reduction of the sludge and reducing the load on the subsequent dewatering unit.

[0021] like Figures 3 to 5As shown, the radial flow sludge settling assembly 23 includes a sludge-water mixture inlet pipe 28 connected to the outlet pipe of the sludge pump 21. Sludge-water mixture dispersion pipes 29 are symmetrically arranged at equal intervals on the outer surface of the sludge-water mixture inlet pipe 28. There are four groups of these dispersion pipes, each group symmetrically distributed at equal intervals around the center point of the sludge-water mixture inlet pipe 28. These four symmetrically distributed dispersion pipes 29 ensure uniform dispersion of sludge into each funnel sedimentation tank 212, preventing uneven settling due to excessively high local sludge concentration. A sludge guide pipe 211 is fitted around the outer side of each group of dispersion pipes 29 to guide sludge into the funnel sedimentation tank 212. 2. The sludge settles internally. A funnel-shaped sedimentation tank 212 is welded to the top of the sludge guide pipe 211. A water equalization guide plate 210 is welded to the outside of the sludge guide pipe 211. The outlet of the mud-water mixture dispersion pipe 29 is located in the channel between the inner wall of the water equalization guide plate 210 and the outer side of the sludge guide pipe 211. After the mud-water mixture flows out of the mud-water mixture dispersion pipe 29, it flows smoothly downward in the channel. Under the action of gravity, the sludge particles settle and are collected in the sludge storage hopper 22 at the bottom through the sludge guide pipe 211. The separated supernatant flows upward over the edge of the water equalization guide plate 210 and is finally discharged through the clear water overflow tank 24 and the clear water drain pipe 25.

[0022] like Figure 6 As shown, the screw press dewatering unit 3 includes a sludge inlet pipe 31 connected to the sludge discharge pipe 26. A dosing and mixing tank 32 is connected to the top of the sludge inlet pipe 31. A mixing and stirring structure 33 (composed of a motor and a stirring rod) is fixedly installed at the top of the dosing and mixing tank 32. A fixed flocculation tank 34 is set on one side of the dosing and mixing tank 32. The dosing and mixing tank 32 and the mixing and stirring structure 33 realize the secondary mixing of concentrated sludge and coagulant (usually PAM), ensuring that the sludge forms a denser floc after entering the fixed flocculation tank 34 (avoiding sludge clogging the discs during dewatering). A mechanical dewatering tank 35 is set on one side of the fixed flocculation tank 34. A disc assembly 36 is installed inside the mechanical dewatering tank 35. A drive motor 37 is installed at one end of the mechanical dewatering tank 35. The disc assembly 36 adopts the principle of screw extrusion. For sludge that still contains extremely fine particles after concentration (which is easy to adhere), efficient dewatering is achieved through the tiny gaps between the discs (the above is existing technology and will not be elaborated on here).

[0023] like Figure 6As shown, the output shaft of the drive motor 37 is connected to the laminated plate assembly 36. The bottom ends of the fixed flocculation tank 34 and the mechanical dewatering tank 35 are connected to the same bracket 39. A sludge outlet pipe 310 is embedded on one side of the bottom end of the mechanical dewatering tank 35. A tailwater outlet pipe 311 is installed at one end of the mechanical dewatering tank 35 below the drive motor 37. The dewatered sludge discharged from the sludge outlet pipe 310 and the tailwater discharged from the tailwater outlet pipe 311 achieve complete solid-liquid separation, completing the entire process of treating the ultrafine particles of the bottom sludge. The front of the fixed flocculation tank 34 is fixed. The control box 38 is installed, and the drive motor 37 is composed of a motor and a reducer. The rotating shaft of the reducer is connected to the stacked plate group 36 by a flat key. The combination of motor and reducer drives the stacked plate group 36 to ensure that it operates at a stable speed (which can be adjusted by the control box 38), avoiding excessive speed that could cause the flocs to break. The flat key connection ensures transmission stability and reduces equipment operating noise. The bottom of the support 39 fits snugly against the ground, and the support 39 improves the overall stability of the equipment, preventing vibration from affecting the dewatering effect during the dewatering process.

[0024] Case 1: Dosing and Operation Scheme for High-Concentration Sludge Treatment When the influent flow rate is 10 m³ / h and the mixed liquor suspended solids concentration (MLSS) is ≥10 g / L (12 g / L in this case), the "PAC+PAM" dosing mode is adopted. The sludge return pump 118 is turned off to prevent sludge backflow. Then, PAC and PAM are quantitatively added through the plunger metering pump 17 so that PAC and PAM enter the three-compartment coagulation and flocculation tank 18. At this time, the PAC dosage is 0.18 g / L, and the PAM dosage is 0.003 g / L, 0.006 g / L, 0.009 g / L, 0.012 g / L and 0.018 g / L. See Figure 7 It can be seen that when the PAM dosage is 0.009 g / L, the turbidity of the effluent from the wastewater sedimentation tank 110 is the lowest (3.2 NTU). This case proves that when treating high-concentration sludge (MLSS≥10 g / L), the simple “PAC+PAM” addition mode can achieve the ideal treatment effect without the need to start sludge return or add fly ash to assist flocculation.

[0025] Case 2: Dosing and Operation Scheme for Medium-Concentration Sludge Treatment When the influent flow rate is 10 m³ / h and 1 g / L ≤ MLSS ≤ 10 g / L (8 g / L in this case), the "PAC + PAM + internal recirculation" operation mode is adopted. The sludge recirculation pump 118 is turned on to make the sludge recirculate internally. The recirculation ratio is controlled at 0.1, 0.2, 0.3, 0.4 and 0.5 respectively. At this time, the plunger metering pump 17 quantitatively adds PAC and PAM, so that PAC and PAM enter the three-compartment coagulation and flocculation tank 18. The PAC dosage is 0.18 g / L and the PAM dosage is 0.009 g / L. See Figure 8 It can be seen that when the return ratio is 0.3, the turbidity of the effluent from the sewage sedimentation tank 110 is the lowest, with a turbidity of 4.5 NTU. This indicates that when the sludge concentration is medium, the particle density and gravity of the three-compartment coagulation and flocculation tank 18 can be increased by increasing the sludge return. The turbidity of the effluent is reduced by the co-precipitation effect formed by the flocs and the endogenous inorganic particles of the returned sludge.

[0026] Case 3: Dosing and Operation Scheme for Low-Concentration Sludge Treatment When the influent flow rate is 10 m³ / h and MLSS ≤ 1 g / L (0.5 g / L in this case), the "PAC+PAM+internal reflux+co-sedimentation" operation mode is adopted. The sludge return pump 118 is turned on to make the sludge internally refluxed, and the reflux ratio is controlled at 0.3. At this time, PAC, PAM and fly ash are quantitatively added through the plunger metering pump 17, so that PAC, PAM and fly ash enter the three-compartment coagulation and flocculation tank 18. The PAC dosage is 0.18 g / L, the PAM dosage is 0.009 g / L, and the fly ash dosages are 0 g / L, 1 g / L, 2 g / L, 4 g / L, 6 g / L and 8 g / L, respectively. See Figure 9 It can be seen that when the amount of fly ash added is 6g / L, the turbidity of the effluent from the sewage sedimentation tank 110 is the lowest, with a turbidity of 4.0 NTU. This indicates that when the sludge concentration is low, fly ash can be added to increase the "gravity nucleus" of the flocs, thereby achieving the co-sedimentation effect of the flocs and fly ash, thus reducing the turbidity of the effluent.

[0027] Case 4: Operation Scheme of Multi-Layer Radial Flow Sludge Thickening Unit 2 for Low-Concentration Sludge Treatment When the influent flow rate of the wastewater sedimentation tank 110 is 10 m³ / h and the MLSS is ≤1 g / L, the "PAC+PAM+internal recirculation+co-sedimentation" operation mode is adopted. The sludge recirculation pump 118 is turned on to allow the sludge to recirculate internally. The recirculation ratio is controlled to be 0.3 through the sludge recirculation pump 118. Then, PAC, PAM and fly ash are quantitatively added through the plunger metering pump 17, so that PAC, PAM and fly ash enter the interior of the three-compartment coagulation and flocculation tank 18. At this time, the PAC dosage is 0.18 g / L, the PAM dosage is 0.009 g / L, and the fly ash dosage is 6 g / L. Under this condition, the sludge influent flow rate of the multi-layer radial flow sludge thickening unit 2 is 1 m³ / h, the sludge moisture content is greater than 98%, and the hydraulic retention time of the multi-layer radial flow sludge thickening unit 2 is 0.5 h, 1 h, 2 h, 4 h, 6 h and 8 h.

[0028] See Figure 10It can be seen that when the hydraulic retention time of the multi-layer radial flow sludge thickening unit 2 is 4 hours, the sludge moisture content is reduced to 85%. If the retention time is extended to 8 hours, the moisture content is further reduced to 80%. Considering both treatment efficiency and economy, the optimal hydraulic retention time is 4 hours. This result shows that the multi-layer radial flow structure described in this invention significantly improves the thickening efficiency, and its required retention time is much shorter than the 12-24 hours required by the traditional multi-layer radial flow sludge thickening unit 2.

[0029] Working principle: The mixture of mud and water from polluted river and lake bottom sediment enters evenly into the three-compartment coagulation and flocculation tank 18 of the high-efficiency co-precipitation unit 1 through the inlet pipe 12. At the same time, the PAC reagent tank 13 stores polyaluminum chloride, the PAM reagent tank 14 stores polyacrylamide, and the fly ash reagent tank 15 stores fly ash, providing reagents for subsequent coagulation and flocculation reactions. The reagent storage tank 120 can increase the reagent reserve and facilitate subsequent replenishment. Next, the plunger metering pump 17 adjusts the dosage according to the bottom sludge concentration, and accurately adds PAC, PAM, and fly ash into the three-compartment coagulation and flocculation tank 18. The agitator 16 at the top of the dosing tank 11 is started to ensure that the concentration of the reagents in the PAC reagent tank 13, PAM reagent tank 14, and fly ash reagent tank 15 is uniform, avoiding sedimentation and stratification. On the other hand, it ensures that the sludge and water in the three-compartment coagulation and flocculation tank 18 are fully mixed with the reagents, improving the mixing uniformity and creating favorable conditions for the subsequent coagulation and flocculation reaction. After the sludge and water react in the three-stage coagulation and flocculation tank 18, they simultaneously enter the sewage sedimentation tank 110 through the water distribution compartment 19 (the sludge and water enter the first sewage sedimentation tank 110, causing the liquid level in the sewage sedimentation tank 110 to rise. At this time, the increased liquid level enters the second sewage sedimentation tank 110 along the guide chamber 111, and so on, so that the sludge and water flow). Furthermore, due to the increased sedimentation area and shortened sedimentation path of ultrafine particles by the inclined tube assembly 112 (using 60° inclined honeycomb tubes) inside the sewage sedimentation tank 110, the sedimentation efficiency is improved. The supernatant after sedimentation enters the clear water chamber 114 and is discharged from the equipment by the clear water return pump 115, realizing the recycling of water resources. The settled sludge falls into the continuous sludge hopper 116 at the bottom of the sewage sedimentation tank 110 (which adopts a conical design to avoid sludge accumulation and blockage and ensure continuous sludge discharge). The settled sludge is returned to the three-compartment coagulation and flocculation tank 18 via the sludge return pump 118. The flocs in the returned sludge are used as "seeds" to promote the formation of new flocs and further improve the flocculation effect. After the equipment is shut down, it can be cleaned and maintained through the drain pipe 119 to reduce the risk of residual sludge clumping. The suspended ladder 121 makes it easy for operators to inspect and maintain the equipment at the top of the dosing tank 11, improving operational safety. When the sludge is not recirculated, the sludge inlet pump 21 is activated. The sludge-water mixture inlet pipe 28 receives the sludge from the sludge inlet pump 21. Four sets of sludge-water mixture dispersion pipes 29 (four in each set, symmetrically distributed at equal intervals around the center point of the sludge-water mixture inlet pipe 28) are symmetrically arranged on its outer surface to evenly disperse the sludge into each funnel sedimentation tank 212, avoiding uneven settling due to excessively high local sludge concentration. Each set of sludge-water mixture dispersion pipes 29 guides the sludge into the space between the outer side of the sludge guide pipe 211 and the inner side of the water equalization guide plate 210. At this time, the sludge enters the sludge storage hopper 22 along the space between the guide funnel sedimentation tank 212 and the outer side of the sludge-water mixture inlet pipe 28, and then enters the sludge discharge pipe 26 along the sludge storage hopper 22. Simultaneously, the supernatant from sludge separation flows along the guide funnel sedimentation tank 212 towards the vertical outer wall 27. The sludge flows into the clear water overflow tank 24 and is then discharged or reused through the clear water drain pipe 25. The sludge flows into the sludge inlet pipe 31 through the sludge discharge pipe 26. The sludge then enters the dosing and mixing tank 32, where the mixing structure 33 mixes the sludge and the chemicals, causing the impurities in the sludge to react with the chemicals to form flocs. The mixed sludge then enters the fixed flocculation tank 34 for further flocculation and then enters the mechanical dewatering tank 35. In the mechanical dewatering tank 35, the stacked plate assembly 36 rotates under the drive of the drive motor 37, squeezing out the water from the sludge through the stacked plate assembly 36 (the above is prior art and will not be elaborated on here), thus achieving sludge dewatering. The dewatered sludge is discharged from the sludge outlet 310, and the squeezed-out tailwater is discharged through the tailwater outlet pipe 311.

[0030] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it.

Claims

1. An integrated device for sedimentation, concentration, and dewatering of extremely fine particles in polluted river and lake sediment, characterized in that, The system includes a high-efficiency co-precipitation unit (1), the discharge end of which is connected to a multi-layer radial flow sludge thickening unit (2), the discharge end of which is connected to a screw press dewatering unit (3), and an electrical control box (4) connected to the outside of the high-efficiency co-precipitation unit (1). The high-efficiency co-precipitation unit (1) includes a dosing tank (11) placed on the ground, and the dosing tank (11) contains a three-compartment coagulation and flocculation tank (18). 11) A PAC agent tank (13) is installed inside the three-compartment coagulation and flocculation tank (18) on one side. A PAM agent tank (14) is installed inside the dosing and dispensing tank (11) on one side of the PAC agent tank (13). A fly ash agent tank (15) is installed inside the dosing and dispensing tank (11) on one side of the PAM agent tank (14). A sludge return pump (118) is installed at the bottom of the dosing and dispensing tank (11). A clean water return pump (115) is installed inside the dosing and dispensing tank (11).

2. The integrated equipment for sedimentation, concentration, and dewatering of extremely fine particles in polluted river and lake sediment as described in claim 1, characterized in that, The top of the dosing tank (11) is equipped with a stirrer (16) located inside the PAC reagent tank (13), PAM reagent tank (14), fly ash reagent tank (15), and three-compartment coagulation and flocculation tank (18). A water inlet pipe (12) is symmetrically embedded at the top of one end of the dosing tank (11) at the top of the three-compartment coagulation and flocculation tank (18). A drain pipe (119) is symmetrically embedded at the bottom of one end of the dosing tank (11) at the bottom of the three-compartment coagulation and flocculation tank (18). A plunger metering pump (17) is installed on one side of the stirrer (16) at the top of the PAC reagent tank (13), PAM reagent tank (14), and fly ash reagent tank (15) above the dosing tank (11). The inlet ends of the three plunger metering pumps (17) are located inside the PAC reagent tank (13), PAM reagent tank (14), and fly ash reagent tank (15), respectively, and the outlet ends of the three plunger metering pumps (17) are located inside the three-compartment coagulation and flocculation tank (18), respectively.

3. The integrated equipment for sedimentation, concentration, and dewatering of extremely fine particles in polluted river and lake sediment as described in claim 2, characterized in that, The dosing tank (11) is located inside the outlet of the three-compartment coagulation and flocculation tank (18) and has a water distribution compartment (19). The dosing tank (11) is located inside the outlet of the water distribution compartment (19) and has a sewage sedimentation tank (110). The sewage sedimentation tank (110) is located inside the flow guiding chamber (111). The number of sewage sedimentation tanks (110) and flow guiding chambers (111) is set to three. The three sewage sedimentation tanks (110) are all equipped with inclined tube supports (113). One end of the inclined tube support (113) is equipped with an inclined tube assembly (112). The dosing tank (11) is located inside the flow guiding chamber (111) and has a clear water chamber (114). The clear water return pump (115) is installed at the bottom of the inner wall of the clear water chamber (114).

4. The integrated equipment for sedimentation, concentration, and dewatering of extremely fine particles in polluted river and lake sediment as described in claim 3, characterized in that, The bottom of each of the three sewage sedimentation tanks (110) is connected to a continuous sludge hopper (116). A fixed bracket (117) is installed on the outside of the dosing tank (11) located on the outside of the three sewage sedimentation tanks (110). The bottom of the three continuous sludge hoppers (116) is connected to the same sludge return pump (118) through a pipe. The discharge end of the sludge return pump (118) is connected to the inside of the three-compartment coagulation and flocculation tank (18) through a pipe. A storage tank (120) is set inside the dosing tank (11) at the bottom of the PAC agent tank (13). A suspended ladder (121) is installed on the outside of the dosing tank (11) at one end of the storage tank (120).

5. The integrated equipment for sedimentation, concentration, and dewatering of extremely fine particles in polluted river and lake sediment as described in claim 4, characterized in that, The multi-layer radial flow sludge thickening unit (2) includes a sludge inlet pump (21) connected to the bottom pipes of the three continuous sludge hoppers (116). The discharge end of the sludge inlet pump (21) is connected to a radial flow sludge settling assembly (23) through a pipe. A sludge storage hopper (22) is sleeved on the outside of the pipe connecting the discharge end of the sludge inlet pump (21) and the radial flow sludge settling assembly (23). A sludge discharge pipe (26) is embedded at the bottom of the sludge storage hopper (22). A vertical outer wall (27) is connected to the top of the sludge storage hopper (22).

6. The integrated equipment for sedimentation, concentration, and dewatering of extremely fine particles of polluted river and lake sediment according to claim 5, characterized in that, The top of the vertical outer wall (27) is connected to a clear water overflow pool (24), and a clear water drain pipe (25) is embedded in the bottom of the clear water overflow pool (24).

7. The integrated equipment for sedimentation, concentration, and dewatering of extremely fine particles in polluted river and lake sediment as described in claim 6, characterized in that, The radial flow sludge settling assembly (23) includes a sludge-water mixture inlet pipe (28) that connects to the outlet pipe of the sludge pump (21), and sludge-water mixture dispersion pipes (29) are symmetrically arranged at equal intervals on the outer surface of the sludge-water mixture inlet pipe (28).

8. The integrated equipment for sedimentation, concentration, and dewatering of extremely fine particles in polluted river and lake sediment as described in claim 7, characterized in that, The mud-water mixture dispersion pipe (29) is set in four groups. Each group of mud-water mixture dispersion pipes (29) is symmetrically distributed at equal intervals around the center point of the mud-water mixture inlet pipe (28), and there are four of them. Each group of mud-water mixture dispersion pipes (29) is fitted with a sludge guide pipe (211) on the outside. A funnel sedimentation tank (212) is welded to the top of the sludge guide pipe (211). A water equalization guide plate (210) is welded to the outside of the sludge guide pipe (211). The outlet of the mud-water mixture dispersion pipe (29) is located between the inner wall of the water equalization guide plate (210) and the outside of the sludge guide pipe (211).

9. An integrated equipment for sedimentation, concentration, and dewatering of extremely fine particles in polluted river and lake sediments according to claim 8, characterized in that, The PAC dosage was 0.18 g / L, the PAM dosage was 0.003 g / L, 0.006 g / L, 0.009 g / L, 0.012 g / L and 0.018 g / L, the fly ash dosage was 0 g / L, 1 g / L, 2 g / L, 4 g / L, 6 g / L and 8 g / L, and the sludge return ratio was 0.1, 0.2, 0.3, 0.4 and 0.5.

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