Sand and scale removal device and implementation method in anaerobic treatment system of landfill leachate

Abstract

The present invention relates to a sand and scale removal device and implementation method in a garbage leachate anaerobic treatment system, wherein: the water inlet diversion part is connected to the water inlet pipe section equipped with a hydraulic sand washing mixer; the sand and water separation part is equipped with a cyclone blade agitator; the water outlet collection part is equipped with a water outlet triangular weir and a water outlet annular collection trough; the sand and scale discharge part is equipped with a screw press conveyor and a sand and water separation discharge pipe. The water flows into the circular cylinder and the conical cylinder of the hydraulic cyclone sand removal, and the sand and scale settle and gather in the sand and scale collection bucket under the action of the cyclone blade agitator. The water flows upward through the diversion inclined plate or inclined pipe, and the rising water is collected and discharged from the system through the clear liquid outlet pipe. The sand and scale are transported and lifted by the screw press conveyor, squeezed and dehydrated, and the fine sand and scale blocks are discharged from the system. The present invention integrates the sand washing, sand settling and sand and water separation functions into an integrated device to achieve non-stop emptying and efficient and stable operation of the leachate anaerobic treatment system.

Description

Technical Field

[0001] The present invention relates to the technical field of landfill leachate treatment and the related field of wastewater treatment equipment, and in particular to a device and implementation method for removing sand and inorganic sediments from an anaerobic treatment system of leachate from a domestic waste incineration plant. Background Art

[0002] At present, my country's garbage classification and collection system is not yet perfect, and domestic garbage is easily mixed with inorganic garbage such as fine sand generated by road sweeping; the leachate itself contains a high content of inorganic salts, and these inorganic substances will eventually enter the leachate treatment system. The treatment process generally adopted by my country for the leachate generated by domestic waste incineration plants is "anaerobic + nitrification and denitrification membrane bioreactor", which is equipped with corresponding subsequent deep treatment processes, and the treated effluent meets the corresponding emission standards. Since the hydraulic retention time and sludge retention time of the anaerobic treatment system in the process are relatively long, fine sand is easy to accumulate in the system, causing blockage of the reactor and pipeline. On the other hand, the pH value in the anaerobic treatment system is generally alkaline, and the concentration of calcium and magnesium ions in the leachate is extremely high, which will also easily form inorganic sediments, causing scaling of equipment and blockage of pipelines, which is not conducive to the normal operation of the system.

[0003] Therefore, for the leachate, it is necessary to promptly discharge the fine sand, inorganic scale deposits and other solids in the anaerobic system. The conventional method of removing sand and scale in the anaerobic system is to shut down the anaerobic system and then empty it for dredging and replacement. This can easily lead to a long restart time and operation time of the system, which cannot meet the requirements of the treatment system for uninterrupted operation.

[0004] At present, there is another treatment method that uses the sand settling and sand removal methods in the traditional sewage treatment process. Most of them use traditional methods such as sand settling tanks and sand-water separators. However, the direct application of traditional sewage treatment process equipment to the anaerobic treatment system of garbage leachate for sand removal and descaling has the following defects:

[0005] 1. The inorganic solid particles in the anaerobic system are small and cannot be effectively removed by traditional methods.

[0006] 2. A large amount of anaerobic sludge adheres to the surface of fine sand and inorganic solid scale in the anaerobic system. It is difficult to clean the sludge on the solid surface by traditional methods. The directly discharged fine sand and inorganic matter contain sludge, which can easily cause secondary environmental pollution and serious odor, and also easily lead to the loss of sludge in the anaerobic system.

[0007] 3. Traditional sewage treatment processes mostly adopt a separate design for sand settling and sand removal, that is, the sand settling device and the sand-water separation device are set separately, occupying a large area.

[0008] 4. In the traditional sewage treatment process, there are many devices for sand washing, sand settling and sand-water separation, with a high failure rate, especially the sand lifting device is prone to blockage after long-term operation.

[0009] In view of this, technical personnel in this field are committed to developing a device for discharging sand and inorganic sediments that can keep the anaerobic leachate treatment system running without stopping and emptying, can efficiently remove fine sand and scale, and realize efficient and stable operation of the anaerobic leachate treatment system, so as to solve the problems existing in the above-mentioned treatment method. Summary of the invention

[0010] The task of the present invention is to provide a sand and scale removal device and an implementation method in an anaerobic treatment system for garbage leachate, and integrate the sand washing, sand settling and sand-water separation functions into an integrated device, aiming to achieve the non-stop operation and emptying of the anaerobic leachate treatment system, achieve efficient removal of fine sand and scale, and achieve efficient and stable operation of the anaerobic leachate treatment system, solve the problems of long-term operation of the existing anaerobic leachate treatment system accumulating fine sand and inorganic scale, easily causing blockage and siltation, reducing treatment efficiency, and shortening the service life of the anaerobic treatment system, and has good practical application value.

[0011] The technical solution of the present invention is as follows:

[0012] A sand and scale removal device in a garbage leachate anaerobic treatment system, comprising a frame, a hydraulic sand washing mixer, a water inlet guide part, a sand and water separation part, a water outlet collection part, a sand and scale discharge part and a connecting pipe;

[0013] The water inlet guide part is a circular cylinder, which is installed on the frame. The water inlet guide part is connected to the water inlet pipe section, and the hydraulic sand washing mixer is installed on the water inlet pipe section. A guide inclined plate or inclined pipe is arranged in the middle of the circular cylinder of the water inlet guide part.

[0014] The sand-water separation part is a conical cylinder, the circular cylinder part of which is installed below the water inlet guide part and connected to the bottom of the circular cylinder. A swirl paddle agitator is installed on the top of the sand-water separation part. The swirl paddle agitator consists of a drooping shaft with a spiral body and a horizontal shaft. The horizontal shaft is installed at the bottom of the drooping shaft. Several inclined paddles are evenly arranged on the horizontal shaft. The horizontal shaft is located in the middle of the conical cylinder of the sand-water separation part. A sand and scale collection bucket and a sand settling separation control valve are installed at the bottom outlet of the conical cylinder.

[0015] The effluent collecting part is located above the sand-water separation part, and is equipped with an effluent triangular weir and an effluent annular collecting trough. The effluent triangular weir is arranged on the top of the circular cylinder of the water inlet guide part and is located above the guide inclined plate or inclined tube. The effluent annular collecting trough is installed on the outer ring of the circular cylinder and connected to the clear liquid outlet pipe. The effluent rising from the guide inclined plate or inclined tube overflows through the effluent triangular weir, flows into the effluent annular collecting trough, and then is discharged from the system through the clear liquid outlet pipe and enters the water inlet or circulation pipeline of the anaerobic treatment system of the leachate.

[0016] The sand and scale discharge part is arranged below the sand and scale collecting bucket at the outlet of the conical cylinder of the sand and water separation part. The sand and scale discharge part is equipped with a screw press conveyor and a sand and water separation discharge pipe. The screw press conveyor is sealed and tilted. The power part of the screw press conveyor is located on the ground. The conveying part of the screw press conveyor extends upward and tilted. The outlet part of the screw press conveyor is located at the top above. The screw press conveyor is equipped with a spiral vent valve, a sand and scale separation liquid level control valve and a sensor located at the outlet part of the screw press conveyor. When the sand and scale collection bucket at the bottom of the sand and water separation part collects fine sand and scale blocks, the sensor of the sand and scale discharge part senses that there is no sand and scale blocks falling at the outlet part of the screw press conveyor, and the spiral vent valve, the sand settling separation control valve and the sand and scale separation liquid level control valve are operated. The sand and scale are transported and lifted by the oblique spiral body of the screw press conveyor, squeezed and dehydrated, and the fine sand and scale blocks are discharged from this system, and the drainage is connected to the water inlet or circulation pipeline of the anaerobic treatment system of the leachate through the sand and water separation discharge pipe.

[0017] The hydraulic sand washing mixer is equipped with double Y-shaped flow guide devices connected in series.

[0018] The hydraulic sand washing mixer is provided with a front valve and a rear valve respectively at the front and rear positions of the setting position of the water inlet pipe section.

[0019] A middle water outlet pipe is arranged on the conical cylinder of the sand-water separation part, a middle drain valve is arranged on the middle water outlet pipe, and the middle water outlet pipe is connected to the clear liquid outlet pipe.

[0020] The sand and scale removal device is equipped with a programmable control device to synchronously control the switching of the sand separation control valve, the spiral vent valve and the sand and scale separation liquid level control valve, as well as the operation of the screw press conveyor, so as to realize the sequential batch automatic operation of the sand and scale discharge part.

[0021] A guide plate is arranged in the circular cylinder of the water inlet guide part, the distance between the guide plate and the circular cylinder is 5-15 mm, and the guide length of the guide plate is 0.3-0.5 times of the cylinder diameter.

[0022] The angle at which the circular cylinder of the water inlet guide part is connected to the conical cylinder of the sand-water separation part is 15° to 30°.

[0023] The height of the guide inclined plate or the inclined pipe area of ​​the water inlet guide part is 0.6-1.0m, and the installation inclination angle is 60°-75°.

[0024] The implementation method of the sand and scale removal device in the anaerobic treatment system of landfill leachate is that the water flow mixed with the mixture is discharged from the drainage port or mud discharge port at the bottom of the anaerobic system, and enters the water inlet pipe section and the hydraulic sand washing mixer. The hydraulic turbulence effect is used in the hydraulic sand washing mixer to strengthen the friction cleaning of the mixture and remove the anaerobic sludge and organic matter adhering to the surface of the fine sand scale block;

[0025] The water flow after the hydraulic sand washing mixer enters the circular cylinder of the water inlet guide part of the hydraulic cyclone sand removal and the conical cylinder of the sand-water separation part through the tangential inlet. Through the guide groove in the cylinder, the water flow can flow along the circular cylinder and the conical cylinder to form a hydraulic cyclone. The fine sand and scale blocks with larger specific gravity settle under the action of gravity, and gather into the sand and scale collection bucket along the bottom ramp of the sand-water separation part under the action of the cyclone paddle agitator.

[0026] The water flows upward through the guide inclined plate or inclined tube arranged in the middle of the circular cylinder of the water inlet diversion part, and the sinking of fine sand or scale blocks is accelerated by the action of the guide inclined plate or inclined tube, thereby improving the effect of sand and scale removal. The rising effluent overflows through the effluent triangular weir and enters the effluent annular collection tank located on the outer circle of the circular cylinder. After the effluent is collected, it is discharged from the system through the clear liquid outlet pipe and enters the water inlet or circulation pipeline of the anaerobic leachate treatment system.

[0027] After the sand and scale collecting bucket at the bottom of the sand and water separation part collects fine sand and scale blocks, it passes through the sensor set at the outlet of the sand and scale discharge part. When there is no sand and scale blocks falling, the operation of the screw press conveyor is first shut down, and the spiral vent valve is opened to empty and then closed; then the sand settling separation control valve is opened to allow the deposited sand, water and scale blocks to fill the sand and scale discharge part together and then the sand settling separation control valve is closed; then the sand and scale separation liquid level control valve is opened to balance the water level of the spiral part of the screw press conveyor and then closed; then the screw press conveyor is opened for separation operation and will not be operated until no discharge is detected at the discharge port; finally, the fine sand and scale blocks are discharged from the system through the sealed oblique screw conveyor, lifting, squeezing and dehydration, and the drainage is connected to the water inlet or circulation pipeline of the anaerobic treatment system of the leachate through the sand and water separation discharge pipe.

[0028] According to the non-stop sand and scale removal device and implementation method in the anaerobic treatment system of garbage leachate of the present invention, the functions of sand washing, sand settling and sand-water separation are designed and integrated into an integrated device, which can realize the non-stop operation and emptying of the anaerobic treatment system of leachate, realize the efficient removal of fine sand and scale, and realize the efficient and stable operation of the anaerobic treatment system of leachate.

[0029] The sand and scale removal device in the anaerobic treatment system of landfill leachate of the present invention can realize the integrated functions of sand washing, sand settling and sand removal, and has the advantages of simple structure, reasonable design, space saving, convenient operation and use, low operation and maintenance cost, etc.; it can realize stable sand and scale removal in the anaerobic treatment system of leachate, and at the same time avoid the risk of anaerobic sludge loss; and improve the operation efficiency and service life of the anaerobic treatment system.

[0030] The sand and scale removal method of the present invention can produce a high removal effect on the fine sand and scale accumulated after the long-term operation of the anaerobic leachate treatment system, and can remove the fine sand with a particle size greater than 0.2 mm in the anaerobic system. The method realizes the continuous operation of the effluent of the cyclone sand and scale removal, and the batch operation of the sand discharge, thereby improving the operation stability of the equipment. The method can optimize the monitoring device provided, can realize the automatic control operation through the PLC, improve the efficiency of the automatic operation, and ensure a good treatment effect. While realizing the sand and scale removal function, the method will not cause the loss of sludge in the anaerobic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of a sand and scale removal device in an anaerobic treatment system for landfill leachate of the present invention.

[0032] Reference numerals:

[0033] 1 is a water inlet pipe section, 2 is a front valve, 3 is a hydraulic sand washing mixer, 4 is a rear valve, 5 is a water inlet diversion part, 6 is a sand-water separation part, 7 is a swirl blade agitator, 8 is a mid-position vent valve, 9 is a diversion inclined plate or inclined pipe, 10 is a water outlet triangular weir, 11 is a water outlet collection part, 12 is a clear liquid outlet pipe, 13 is a sand settling separation control valve, 14 is a sand and scale discharge part, 15 is a screw press conveyor, 16 is a spiral vent valve, 17 is a sand and scale separation level control valve, and 18 is a sand and water separation discharge pipe. DETAILED DESCRIPTION

[0034] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0035] See also Figure 1 The present invention provides a sand and scale removal device in an anaerobic treatment system for landfill leachate, which is mainly composed of a frame, a hydraulic sand washing mixer 3, an inlet guide part 5, a sand and water separation part 6, an outlet water collection part 11, a sand and scale discharge part 14 and a connecting pipe.

[0036] The water inlet guide part 5 is a circular cylinder, which is installed on the frame. The water inlet guide part 5 is connected to the water inlet pipe section 1, and the hydraulic sand washing mixer 3 is installed on the water inlet pipe section 1 through a flange. The hydraulic sand washing mixer 3 is equipped with a double Y-type guide device in series, and the ratio of the length of the Y-type guide body to the diameter of the water inlet pipe is 2:1~2.5:1, wherein the middle angle of the Y-type guide body is 30°~45°. The hydraulic sand washing mixer 3 is respectively installed with a front valve 2 and a rear valve 4 at the front and rear positions of the setting position of the water inlet pipe section 1. A guide plate is arranged in the circular cylinder of the water inlet guide part 5, and the spacing between the guide plate and the circular cylinder is 5~15mm, and the guide length of the guide plate is 0.3~0.5 times the cylinder diameter. A guide inclined plate or inclined tube 9 is arranged in the middle of the circular cylinder of the water inlet guide part 5. The height of the guide inclined plate or inclined tube 9 area is 0.6-1.0m, the installation inclination angle is 60°-75°, and the inclined plate spacing or tube diameter is about 50-150mm.

[0037] The sand-water separation part 6 is a conical cylinder, and the circular cylinder part of the conical cylinder is installed below the water inlet guide part 5 and connected to the bottom of the circular cylinder. The angle between the circular cylinder of the water inlet guide part 5 and the conical cylinder of the sand-water separation part 6 is 15° to 30°. A swirl paddle agitator 7 is installed on the top of the sand-water separation part 6. The swirl paddle agitator 7 is composed of a drooping shaft with a spiral body and a horizontal shaft. The length of the drooping shaft is 3 to 5m. The horizontal shaft is installed at the bottom of the drooping shaft. The horizontal shaft is located in the middle of the conical cylinder of the sand-water separation part 6. Several inclined paddles are evenly arranged on the horizontal shaft. The diameter of the paddle is 0.95 to 0.98 times the bottom diameter of the sand-water separation part 6. The distance between the top of the paddle and the tank wall is determined according to the critical particle size of the material, and is generally not less than 10mm. A sand and scale collection bucket and a sand settling separation control valve 13 are installed at the bottom outlet of the conical cylinder. A middle water outlet pipe is arranged on the conical cylinder of the sand-water separation part 6 , a middle drain valve 8 is installed on the middle water outlet pipe, and the middle water outlet pipe is connected to the clear liquid outlet pipe 12 .

[0038] The effluent collection part 11 is located above the sand-water separation part 6. The effluent collection part 11 is equipped with an effluent triangular weir 10 and an effluent annular collection tank. The effluent triangular weir 10 is arranged at the top of the circular cylinder of the inlet diversion part 5 and is located above the diversion inclined plate or inclined tube 9. The effluent annular collection tank is installed on the outer ring of the circular cylinder and connected to the clear liquid outlet pipe 12. The effluent guided up by the diversion inclined plate or inclined tube 9 overflows through the effluent triangular weir 10, flows into the effluent annular collection tank, and then discharges from the system through the clear liquid outlet pipe 12 and enters the water inlet or circulation pipeline of the anaerobic treatment system of the leachate.

[0039] The sand and scale discharge part 14 is arranged below the sand and scale collection bucket at the outlet of the conical cylinder of the sand and water separation part 6. The sand and scale discharge part 14 is equipped with a screw press conveyor 15 and a sand and water separation discharge pipe 18. The screw press conveyor 15 is installed in a sealed and inclined manner, the power part of the screw press conveyor 15 is located on the ground, the conveying part of the screw press conveyor 15 extends upward and the outlet part of the screw press conveyor 15 is located at the top. The screw press conveyor 15 is equipped with a spiral vent valve 16, a sand and scale separation liquid level control valve 17 and a sensor located at the outlet part of the screw press conveyor 15. When the sand and scale collecting bucket at the bottom of the sand-water separation section 6 collects fine sand and scale blocks, the sensor of the sand and scale discharge section 14 senses that no sand and scale blocks fall from the outlet of the screw press conveyor 15, and operates the spiral vent valve 16, the sand separation control valve 13 and the sand and scale separation liquid level control valve 17. The sand and scale are transported and lifted by the oblique spiral body of the screw press conveyor 15, squeezed and dehydrated, and the fine sand and scale blocks are discharged from the system. At the same time, the drainage is connected to the water inlet or circulation pipeline of the anaerobic treatment system of the leachate through the sand-water separation discharge pipe 18.

[0040] The sand and scale removal device in the anaerobic treatment system of the landfill leachate of the present invention is equipped with a programmable control device to synchronously control the switching of the sand separation control valve 13, the spiral vent valve 16 and the sand and scale separation liquid level control valve 17, as well as the operation of the screw press conveyor 15, so as to realize the sequential batch automatic operation of the sand and scale discharge part 14.

[0041] like Figure 1 As shown, the present invention also provides an implementation method of a sand and scale removal device in an anaerobic treatment system for landfill leachate, which is specifically as follows:

[0042] The water flow mixed with the mixture is discharged from the drainage outlet or mud outlet at the bottom of the anaerobic system and enters the water inlet pipe section 1 and the hydraulic sand washing mixer 3. The hydraulic turbulence effect is used in the hydraulic sand washing mixer 3 to strengthen the friction cleaning of the mixture and remove the anaerobic sludge and organic matter adhering to the surface of the fine sand scale.

[0043] The water flow after passing through the hydraulic sand washing mixer 3 enters into the circular cylinder of the water inlet guide part 5 and the conical cylinder of the sand-water separation part 6 of the hydraulic cyclone sand removal through the tangential inlet. Through the guide plate groove in the cylinder body, the water flow can flow along the circular cylinder and the conical cylinder to form a hydraulic cyclone. The fine sand and scale blocks with larger specific gravity settle under the action of gravity, and gather into the sand and scale collecting bucket along the bottom ramp of the sand-water separation part 6 under the action of the cyclone paddle agitator 7.

[0044] The water flows upward through the guide inclined plate or inclined tube 9 arranged in the middle of the circular cylinder of the water inlet guide part 5. The sinking of fine sand or scale blocks is accelerated by the action of the guide inclined plate or inclined tube 9, thereby improving the effect of sand and scale removal. The rising effluent overflows through the effluent triangular weir 10 and enters the effluent annular collection tank located on the outer circle of the circular cylinder. After the effluent is collected, it is discharged from the system through the clear liquid outlet pipe 12 and enters the water inlet or circulation pipeline of the anaerobic leachate treatment system.

[0045] After the sand and scale collection bucket at the bottom of the sand and water separation section 6 collects fine sand and scale blocks, the sensor set at the outlet of the sand and scale discharge section 14, when there is no sand and scale blocks falling, first shut down the operation of the screw press conveyor 15, open the spiral vent valve 16 to empty and then close it. Then open the sand settling separation control valve 13, let the deposited sand and scale water fill the sand and scale discharge section 14 together, and then close the sand settling separation control valve 13. Then open the sand and scale separation liquid level control valve 17, balance the water level of the spiral part of the screw press conveyor 15 and then close it. Then open the screw press conveyor 15 for separation operation, and run it again after no discharge is detected at the discharge port. Finally, the fine sand and scale blocks are discharged from the system through the sealed oblique screw conveyor lifting, squeezing and dehydration, and the drainage is connected to the water inlet or circulation pipeline of the anaerobic treatment system of the leachate through the sand and water separation discharge pipe 18.

[0046] The sand and scale removal device and implementation method in the anaerobic treatment system of landfill leachate of the present invention can realize the integration of sand washing, sand settling and sand removal functions, and has the advantages of simple structure, reasonable design, space saving, convenient operation and use, low operation and maintenance cost, etc.; it can realize stable sand and scale removal in the anaerobic treatment system of leachate, and at the same time avoid the risk of anaerobic sludge loss; and improve the operation efficiency and service life of the anaerobic treatment system.

[0047] Of course, those skilled in the art should realize that the above embodiments are only used to illustrate the present invention, and are not used to limit the present invention. As long as they are within the spirit of the present invention, changes and modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A sand and scale removal device in an anaerobic treatment system for landfill leachate, characterized in that: It comprises a frame, a hydraulic sand washing mixer (3), a water inlet guide part (5), a sand-water separation part (6), a water outlet collection part (11), a sand and scale discharge part (14), and connecting pipes; The water inlet guide part (5) is a circular cylinder, which is mounted on the frame. The water inlet guide part (5) is connected to the water inlet pipe section (1), and the water-powered sand washing mixer (3) is mounted on the water inlet pipe section (1). A guide inclined plate or inclined pipe (9) is arranged in the middle of the circular cylinder of the water inlet guide part (5). The sand-water separation part (6) is a conical cylinder, the circular cylinder part of which is installed below the water inlet guide part (5) and connected to the bottom of the circular cylinder, the top of the sand-water separation part (6) is equipped with a swirl blade agitator (7), the swirl blade agitator (7) is composed of a drooping shaft with a spiral body and a horizontal shaft, the horizontal shaft is installed at the bottom end of the drooping shaft, and a plurality of inclined blades are evenly arranged on the horizontal shaft, the horizontal shaft is located in the middle of the conical cylinder of the sand-water separation part (6), and a sand and scale collection bucket and a sand settling separation control valve (13) are installed at the bottom outlet of the conical cylinder; The effluent collecting section (11) is located above the sand-water separation section (6). The effluent collecting section (11) is equipped with an effluent triangular weir (10) and an effluent annular collecting trough. The effluent triangular weir (10) is arranged at the top of the circular cylinder of the water inlet guide section (5) and is located above the guide inclined plate or inclined tube (9). The effluent annular collecting trough is installed on the outer ring of the circular cylinder and connected to the clear liquid outlet pipe (12). The effluent rising from the guide inclined plate or inclined tube (9) overflows through the effluent triangular weir (10), flows into the effluent annular collecting trough, and then is discharged from the system through the clear liquid outlet pipe (12) and enters the water inlet or circulation pipeline of the anaerobic treatment system of the leachate. The sand and scale discharge section (14) is arranged below the sand and scale collection bucket at the outlet of the conical cylinder of the sand and water separation section (6). The sand and scale discharge section (14) is equipped with a screw press conveyor (15) and a sand and water separation discharge pipe (18). The screw press conveyor (15) is installed in a sealed manner and tilted. The power part of the screw press conveyor (15) is located on the ground. The conveying part of the screw press conveyor (15) extends upward and tilted. The outlet part of the screw press conveyor (15) is located at the top of the upper part. The screw press conveyor (15) is equipped with a spiral vent valve (16), a sand and scale separation liquid level control valve (17) and a screw press valve (18) located on the screw press conveyor. The sensor at the outlet of the screw press conveyor (15) senses that no sand or scale is falling from the outlet of the screw press conveyor (15) after the sand and scale collecting bucket at the bottom of the sand and water separation section (6) collects fine sand and scale. The sensor at the sand and scale discharge section (14) senses that no sand or scale is falling from the outlet of the screw press conveyor (15), and the spiral vent valve (16), the sand settling separation control valve (13) and the sand and scale separation liquid level control valve (17) are operated. The sand and scale are transported and lifted by the oblique spiral of the screw press conveyor (15), squeezed and dehydrated, and the fine sand and scale are discharged from the system. The drainage is connected to the water inlet or circulation pipeline of the anaerobic treatment system of the leachate through the sand and water separation discharge pipe (18).

2. The sand and scale removal device in the anaerobic treatment system for landfill leachate according to claim 1, characterized in that: The hydraulic sand washing mixer (3) is equipped with a double Y-shaped flow guide device connected in series.

3. The sand and scale removal device in the anaerobic treatment system for landfill leachate according to claim 1, characterized in that: The hydraulic sand washing mixer (3) is respectively provided with a front valve (2) and a rear valve (4) at the front and rear positions of the location where the water inlet pipe section (1) is provided.

4. The sand and scale removal device in the anaerobic treatment system for landfill leachate according to claim 1, characterized in that: A middle water outlet pipe is arranged on the conical cylinder of the sand-water separation part (6), a middle drain valve (8) is installed on the middle water outlet pipe, and the middle water outlet pipe is connected to the clear liquid outlet pipe (12).

5. The sand and scale removal device in the anaerobic treatment system for landfill leachate according to claim 1, characterized in that: The sand and scale removal device is equipped with a programmable control device to synchronously control the switching of the sand separation control valve (13), the spiral vent valve (16) and the sand and scale separation liquid level control valve (17), as well as the operation of the screw pressing conveyor (15), so as to realize the sequential batch automatic operation of the sand and scale discharge part (14).

6. The sand and scale removal device in the anaerobic treatment system for landfill leachate according to claim 1, characterized in that: A guide plate is arranged inside the circular cylinder of the water inlet guide part (5); the distance between the guide plate and the circular cylinder is 5 to 15 mm; and the guide length of the guide plate is 0.3 to 0.5 times the cylinder diameter.

7. The sand and scale removal device in the anaerobic treatment system for landfill leachate according to claim 1, characterized in that: The angle at which the circular cylinder of the water inlet guide part (5) is connected to the conical cylinder of the sand-water separation part (6) is 15° to 30°.

8. The sand and scale removal device in the anaerobic treatment system for landfill leachate according to claim 1, characterized in that: The height of the guide inclined plate or inclined pipe (9) area of ​​the water inlet guide part (5) is 0.6 to 1.0 m, and the installation inclination angle is 60° to 75°.

9. The implementation method of the sand and scale removal device in the anaerobic treatment system for landfill leachate according to claim 1, characterized in that: The water flow mixed with the mixture is discharged from the drainage port or mud discharge port at the bottom of the anaerobic system and enters the water inlet pipe section (1) and the hydraulic sand washing mixer (3). The hydraulic turbulence effect is used in the hydraulic sand washing mixer (3) to strengthen the friction cleaning of the mixture and remove the anaerobic sludge and organic matter adhering to the surface of the fine sand scale. The water flow after passing through the hydraulic sand washing mixer (3) enters the circular cylinder of the water inlet guide part (5) of the hydraulic cyclone sand removal and the conical cylinder of the sand-water separation part (6) through the tangential inlet, and the water flow is allowed to flow along the circular cylinder and the conical cylinder through the guide groove in the cylinder to form a hydraulic cyclone, and the fine sand and scale blocks with a larger specific gravity settle under the action of gravity, and are gathered into the sand and scale collection bucket along the bottom ramp of the sand-water separation part (6) under the action of the cyclone paddle stirrer (7); The water flows upward through the guide inclined plate or inclined tube (9) arranged in the middle of the circular cylinder of the water inlet guide part (5). The sinking of fine sand or scale blocks is accelerated by the action of the guide inclined plate or inclined tube (9), thereby improving the effect of sand and scale removal. The rising water overflows through the water outlet triangular weir (10) and enters the water outlet annular collection tank located on the outer ring of the circular cylinder. After the water outlet is collected, it is discharged from the system through the clear liquid outlet pipe (12) and enters the water inlet or circulation pipeline of the anaerobic leachate treatment system. After the fine sand and scale blocks are collected by the sand and scale collecting bucket at the bottom of the sand and water separation section (6), the sensors arranged at the outlet of the sand and scale discharge section (14) are used. When no sand and scale blocks fall, the operation of the screw press conveyor (15) is first shut down, and the screw vent valve (16) is opened to vent and then shut down; then the sand settling separation control valve (13) is opened to allow the deposited sand, water and scale blocks to fill the sand and scale discharge section (14) together, and then the sand settling separation control valve (13) is closed; then the sand and scale separation liquid level control valve (17) is opened to balance the water level of the screw part of the screw press conveyor (15) and then shut down; then the screw press conveyor (15) is opened to perform the separation operation, and the operation is resumed after no discharge is detected at the discharge outlet; finally, the fine sand and scale blocks are discharged from the system through the sealed oblique screw conveyor, lifting, squeezing and dehydration, and the drainage is connected to the water inlet or circulation pipeline of the anaerobic treatment system of the leachate through the sand and water separation discharge pipe (18).

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