A method for an integrated landfill body well to achieve automatic drainage, gas collection and repair

Abstract

The present invention relates to a method for realizing automatic drainage, gas collection and repair of an integrated landfill body well, which is used for landfill leachate treatment. It discloses that both the cage body of the steel reinforcement cage and the pipe body of the well pipe are provided with holes. The steel reinforcement cage is buried in the landfill body, and the top of the steel reinforcement cage is sealed with a sealing layer; the bottom end of the well pipe passes through the sealing layer and is inserted into the steel reinforcement cage, and is wrapped with geotextile. There is a gap between the outer wall of the well pipe and the inner wall of the steel reinforcement cage, and the gap is filled with gravel. The top outlet of the well pipe is sealed with a flange, and a landfill gas collection pipe, a leachate drainage pipe, an injection pipe and a water level monitoring probe are installed on the flange. The water level monitoring probe, the leachate drainage pipe and the injection pipe extend into the well pipe, and the injection pipe bends upward and extends into the leachate drainage pipe. The advantages of the present invention are that it avoids the corrosion of the pump, does not affect the collection of landfill gas, can automatically drain water according to the height of the leachate level, and avoids repeated well drilling in the repair stage, saving operation costs and labor.

Description

Technical Field

[0001] The present invention relates to the field of ecological environment engineering, and particularly to a method for an integrated garbage heap well to achieve automatic drainage, gas collection, and restoration. Background Art

[0002] The extensive use of landfilling has left a large amount of stockpiled garbage and landfills that need operation and maintenance or ecological restoration. Anaerobic reactions occur in the stockpiled garbage, generating toxic and harmful leachate and flammable and harmful landfill gas. Currently, all standardized domestic waste landfills need to be equipped with a perfect leachate and landfill gas drainage system.

[0003] Domestic waste will be artificially compacted when entering the landfill and will also undergo continuous natural settlement under the action of gravity. Therefore, the stockpiled garbage has poor water permeability, and the leachate drainage pipes deep in the heap are squeezed and deformed, resulting in poor drainage effect and forming stagnant water between the heap layers. The stagnant water in the garbage heap affects both the stability of the heap and the collection of landfill gas. Therefore, it is very important to drain the stagnant water in the heap in a timely manner.

[0004] Traditional well-drilling and pumping methods not only cause high-salt leachate to pass through the water pump, exacerbating equipment corrosion, but also pose a potential hazard of explosion when the water level is low and landfill gas is pumped out. In this regard, the utility model patent "Landfill Gas Collection Well Air-Lift Pumping Device" and the invention patent "A Small-Diameter Shaft Structure for Leachate Drainage in a Landfill and a Siltation Blocking Method" lift garbage leachate by injecting gas, but do not consider the problem of landfill gas collection. The methods disclosed in the utility model patents "Landfill Leachate Drainage and Landfill Gas Collection System" and "Horizontal Landfill Gas Collection Well with Auxiliary Vertical Water Pumping and Gas Extraction Device" consider both drainage and gas collection, but both require re-laying pipelines, which are only suitable for use during the construction of landfills and are difficult to meet the needs of treating existing landfills.

[0005] In addition, the above background art does not consider two major problems during the operation and restoration of landfills. On the one hand, manually starting and stopping drainage equipment during the operation period consumes a large amount of manpower, and automation operation is urgently needed. On the other hand, during the restoration period, it is necessary to inject gas into the heap to accelerate degradation, and often new wells need to be drilled. There is an urgent need to achieve integrated drainage, gas collection, and restoration. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for an integrated garbage heap well to achieve automatic drainage, gas collection, and restoration to overcome the above-mentioned difficulties in garbage heap drainage.

[0007] The technical solution of the present invention is based on an automatic control system, a high-pressure air pump, a leachate drainage valve, a water level monitoring probe, a landfill gas collection valve, a landfill gas collection pipe, a leachate drainage pipe, an injection pipe, a flange, a sealing layer, a well pipe, a geotextile, gravel, a steel reinforcement cage, a landfill waste body, and a gas-liquid separation valve. The characteristics are that the automatic drainage, gas collection, and repair method is as follows: The cage body of the steel reinforcement cage and the pipe body of the well pipe are both provided with holes. The steel reinforcement cage is buried in the landfill waste body, and the top of the steel reinforcement cage is sealed with a sealing layer; the bottom end of the well pipe passes through the sealing layer and is inserted into the steel reinforcement cage, and the pipe body of the well pipe is wrapped with a geotextile. There is a gap between the outer wall of the well pipe and the inner wall of the steel reinforcement cage, and the gap is filled with gravel. The top outlet of the well pipe is sealed with a flange, and a landfill gas collection pipe, a leachate drainage pipe, an injection pipe, and a water level monitoring probe are installed on the flange. The liquid level detection end of the water level monitoring probe extends into the well pipe to the leachate detection position; the bottom end of the leachate drainage pipe extends to the bottom of the well pipe and has a gap with the bottom of the well pipe; the air outlet end of the injection pipe extends to the bottom of the well pipe and bends upward at the leachate inlet at the bottom end of the leachate drainage pipe and extends into the leachate drainage pipe, so that the position of the air outlet of the injection pipe in the well pipe is higher than the position of the leachate inlet at the bottom end of the leachate drainage pipe.

[0008] In the present invention, the volume of the gravel is larger than the hole diameter of the steel reinforcement cage. The material of the well pipe is one of PE or HDPE. The top of the well pipe protrudes upward higher than the top of the steel reinforcement cage. The protruding section of the well pipe is a solid pipe, and the pipe section of the well pipe inserted into the steel reinforcement cage is a slotted pipe, that is, it is provided with holes.

[0009] The air inlet of the injection pipe in the present invention is installed with a high-pressure air pump. The height of the air outlet where the injection pipe bends into the leachate drainage pipe from the leachate inlet at the bottom of the leachate drainage pipe is the height for controlling the lowest water level of the leachate in the well pipe.

[0010] The leachate drainage valve in the present invention is installed at the liquid outlet end of the leachate drainage pipe. The outlet of the leachate drainage pipe is connected to a gas-liquid separation valve. The landfill gas collection valve is installed at the gas outlet of the landfill gas collection pipe. The gas inlet of the landfill gas collection pipe passes through the flange and extends into the well pipe, and the position is slightly lower than the lower edge of the flange to ensure the collection efficiency of the landfill gas.

[0011] The air supply control signal output end of the automatic control system in the present invention is connected to the start / stop signal receiving end of the high-pressure air pump through a data line; the detection signal output end of the water level monitoring probe is connected to the liquid level signal receiving end of the automatic control system through a data line, and the automatic control system controls the operation of the high-pressure air pump according to the detection signal of the water level monitoring probe.

[0012] The working principle of the present invention is to arrange the equipment in the following steps:

[0013] Step 1: Take a cylindrical steel reinforcement cage with an open top. Lay a layer of gravel at the bottom of the steel reinforcement cage. The size of the gravel should be slightly larger than the holes in the steel reinforcement cage to prevent it from falling.

[0014] Step 2: Install a well pipe on the central axis of the steel reinforcement cage. Its material is preferably PE or HDPE, and its diameter is slightly smaller than the diameter of the steel reinforcement cage described in Step 1. The bottom of the well pipe abuts against the gravel layer described in Step 1, and the top of the well pipe is sealed with a flange; the upper edge of the well pipe is higher than the upper edge of the steel reinforcement cage. The higher section is a solid pipe, and the section lower than the upper edge of the steel reinforcement cage is a slotted pipe. The side is wrapped with geotextile to prevent solids from entering the pipe through the side holes of the slotted pipe.

[0015] The flange described in Step 3 reserves round holes for the installation of an air injection pipe, a leachate drain pipe, landfill gas collection, and a water level detection probe respectively.

[0016] The upper part of the air injection pipe is connected to a high-pressure air pump, and a bent pipe is set at the bottom and connected to the leachate drain pipe. The opening of the bent pipe is slightly higher than the lower opening of the leachate drain pipe to ensure that the injected gas enters the leachate drain pipe to lift the leachate. The opening height of the bent pipe is the minimum leachate water level height controlled by this method.

[0017] The upper opening of the leachate drain pipe enters the leachate collection system via a valve and a gas-liquid separation valve.

[0018] The lower opening of the landfill gas collection pipe is not lower than the lower edge of the flange to ensure the landfill gas collection efficiency. The upper pipe opening is connected to the landfill gas collection system via a landfill gas collection pipe valve.

[0019] The water level detection probe can be used to detect the leachate water level height and is connected to an automatic control system. When the water level is high, the high-pressure air pump is started, and when the water level is low, the high-pressure air pump is shut down.

[0020] Step 4: Lay gravel around the well pipe and in the steel reinforcement cage up to the top of the steel reinforcement cage;

[0021] Step 5: Drill a well in the landfill waste body. Its diameter is the same as the diameter of the steel reinforcement cage described in Step 1, and its depth is slightly greater than the depth of the steel reinforcement cage. Place the steel reinforcement cage into the well and set a sealing layer at the top of the well.

[0022] After arranging and setting according to the above steps, when the landfill is in the operation stage, the valves of the leachate drain pipe and the landfill gas collection pipe are always open. Start the high-pressure air pump to discharge the leachate through the leachate drain pipe. When the leachate collection volume is small, the high-pressure air pump can be shut down. Or use the water level monitoring probe and the automatic control system to achieve automatic start-stop control.

[0023] When the landfill is in the repair stage, the leachate level is relatively low, and the valves of the leachate drain pipe and the landfill gas collection pipe are usually closed. Aerobic repair can be carried out by injecting high-pressure air.

[0024] The advantages of the present invention are that the leachate extracted by this technology does not pass through a pump, avoiding corrosion of machinery; it can automatically start and stop the high-pressure air pump according to the height of the leachate level, saving operating costs; when the water level is relatively low after the leachate is pumped out, the high-pressure air does not enter the well pipe due to the liquid seal effect, without affecting the collection of landfill gas; the vertical shaft provided can also be used as an air injection well required during the repair period of the landfill, avoiding repeated drilling and saving manpower and material resources. Brief Description of the Drawings

[0025] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 is a schematic diagram of the operation flow principle of the equipment of the present invention;

[0027] Figure 3 is a schematic diagram of the three liquid level structures of shutdown, startup, and low liquid level of the present invention. Detailed Embodiments

[0028] According to Figure 1 、 Figure 2 、 Figure 3As shown in the figure, based on the automatic control system 1, high-pressure air pump 2, leachate drainage valve 3, water level monitoring probe 4, landfill gas collection valve 5, landfill gas collection pipe 6, leachate drainage pipe 7, injection pipe 8, flange 9, sealing layer 10, well pipe 11, geotextile 12, gravel 13, steel reinforcement cage 14, landfill waste body 15, and gas-liquid separation valve 16, the present invention is characterized in that the automatic drainage, gas collection, and repair method is as follows: The cage body of the steel reinforcement cage 14 and the pipe body of the well pipe 11 are both provided with holes. The steel reinforcement cage 14 is buried in the landfill waste body 1, and the top of the steel reinforcement cage 14 is flush with the top surface of the landfill waste body 1. The top of the steel reinforcement cage 14 is sealed with a sealing layer 10; the bottom end of the well pipe 11 passes through the sealing layer and is inserted into the steel reinforcement cage 14, and the pipe body of the well pipe 11 is wrapped with a geotextile 12. There is a gap between the outer wall of the well pipe 11 and the inner wall of the steel reinforcement cage 14, and the gap is filled with gravel. The top outlet of the well pipe 11 is sealed with a flange 9, and a landfill gas collection pipe 6, a leachate drainage pipe 7, an injection pipe 8, and a water level monitoring probe 4 are installed on the flange 9. The liquid level detection end of the water level monitoring probe 4 extends to the bottom of the well pipe 11 to three leachate detection positions: start liquid level A, stop liquid level B, and repair liquid level C; the bottom end of the leachate drainage pipe 7 extends to the bottom of the well pipe 11 and has a gap with the bottom of the well pipe 11; the air outlet end of the injection pipe 8 extends to the bottom of the well pipe, and bends upward at the leachate inlet of the leachate drainage pipe 7 and extends into the leachate drainage pipe 7, so that the position of the air outlet of the injection pipe 8 in the well pipe 11 is higher than the position of the leachate inlet at the bottom end of the leachate drainage pipe 7.

[0029] The volume of the gravel 13 is larger than the hole diameter of the steel reinforcement cage. The material of the well pipe is one of PE or HDPE. The top of the well pipe protrudes upward higher than the top of the steel reinforcement cage. The protruding section of the well pipe is a solid pipe, and the pipe section of the well pipe inserted into the steel reinforcement cage is a slotted pipe, that is, it is provided with holes.

[0030] A high-pressure air pump 2 is installed at the air inlet of the injection pipe 8. The height of the air outlet of the injection pipe 8 bending into the leachate drainage pipe 7 from the leachate inlet of the leachate drainage pipe 7 is the height for controlling the lowest leachate level in the well pipe 11.

[0031] The leachate drainage valve 3 is installed at the liquid outlet end of the leachate drainage pipe 7. The outlet of the leachate drainage pipe 7 is connected to the gas-liquid separation valve 16. The landfill gas collection valve 5 is installed at the gas outlet of the landfill gas collection pipe 6. The gas inlet of the landfill gas collection pipe 6 passes through the flange 9 and extends into the well pipe, and the position is lower than the lower edge of the flange 9 to ensure the landfill gas collection efficiency.

[0032] The air supply control signal output end of the automatic control system 1 is connected to the start and stop signal receiving end of the high-pressure air pump 2 through a data line; the detection signal output end of the water level monitoring probe 4 is connected to the liquid level signal receiving end of the automatic control system 1 through a data line, and the automatic control system 1 controls the operation of the high-pressure air pump 2 according to the detection signal of the water level monitoring probe 4.

[0033] like Figure 1 As shown, a well is drilled in a garbage pile 15, and a steel cage 14 is placed in the cage. From the outside to the inside, there are crushed stone 13, geotextile 12, well pipe 11, steel cage 14 and crushed stone 13, and the top of the steel cage 14 is sealed.

[0034] An air injection pipe 8, a leachate drainage pipe 7 and a water level monitoring probe 4 are installed in the well pipe 11. In addition, an automatic control system 1 is provided to read the signal of the detection probe and feed it back to the high-pressure air pump 2 for controlling the start or stop of the air pump.

[0035] During the landfill operation phase, the valves on the leachate drainage pipe 7 and the landfill gas collection pipe 6 are kept open. Figure 2 As shown, when the water level monitoring probe 4 detects that the water level is high, the high-pressure air pump 2 is started, and the air enters the leachate drainage pipe 7 through the air injection pipe 8 to lift and discharge the leachate. At this time, the leachate drainage pipe 7 and the well pipe 11 form a communicating vessel, and the leachate is higher than the lower edge of the drainage pipe, which can achieve liquid sealing and ensure that high-pressure air does not enter the well pipe 11. And under the monitoring of the water level monitoring probe 4, once the leachate water level is lower than the upper edge of the U-shaped opening of the air injection pipe 7, the pump is shut down. While ensuring that the high-pressure air is fully used to lift the leachate, it is prevented from entering the well pipe 11 to affect the collection of landfill gas.

[0036] During the landfill remediation stage, the valves on the leachate drainage pipe 7 and the landfill gas collection pipe 6 are kept closed. The high-pressure air pump 2 is started to inject air into the well. Since the water level is low during the remediation stage, no liquid seal is formed on the leachate drainage pipe, and air can enter the well and diffuse into the garbage pile through the gravel layer and the steel cage 14, thus achieving aerobic remediation.

Claims

1. A method for an integrated landfill body well to achieve automatic drainage, gas collection, and repair, which includes an automatic control system, a high-pressure air pump, a leachate drainage valve, a water level monitoring probe, a landfill gas collection valve, a landfill gas collection pipe, a leachate drainage pipe, an injection pipe, a flange, a sealing layer, a well pipe, a geotextile, gravel, a steel reinforcement cage, a landfill body, and a gas-liquid separation valve, characterized in that The described automatic drainage, gas collection, and repair method is as follows: The cage body of the steel reinforcement cage and the pipe body of the well pipe are both provided with holes. The steel reinforcement cage is buried in the garbage heap body, and the top of the steel reinforcement cage is sealed with a sealing layer. The bottom end of the well pipe passes through the sealing layer and is inserted into the steel reinforcement cage. The pipe body of the well pipe is wrapped with geotextile. There is a gap between the outer wall of the well pipe and the inner wall of the steel reinforcement cage, and the gap is filled with crushed stones. The top outlet of the well pipe is sealed with a flange, and a landfill gas collection pipe, a leachate drain pipe, an injection pipe, and a water level monitoring probe are installed on the flange. The high and low liquid level detection ends of the water level monitoring probe extend into the well pipe to the leachate detection position. The bottom end of the leachate drain pipe extends to the bottom of the well pipe and has a gap with the bottom of the well pipe. The air outlet end of the injection pipe extends to the bottom of the well pipe and bends upward at the leachate inlet at the bottom end of the leachate drain pipe and extends into the leachate drain pipe, so that the position of the air outlet of the injection pipe in the well pipe is higher than the position of the leachate inlet at the bottom end of the leachate drain pipe.

2. A method for realizing automatic drainage, gas collection, and repair of an integrated garbage heap well according to claim 1, characterized in that The volume of the crushed stones is larger than the hole diameter of the steel reinforcement cage. The material of the well pipe is one of PE or HDPE. The top of the well pipe protrudes upward higher than the top of the steel reinforcement cage. The protruding section of the well pipe is a solid pipe, and the pipe section of the well pipe inserted into the steel reinforcement cage is a slotted pipe, that is, it is provided with holes.

3. A method for an integrated garbage heap well to achieve automatic drainage, gas collection, and repair, characterized in that A high-pressure air pump is installed at the air inlet of the injection pipe. The height of the air outlet where the injection pipe bends into the leachate drain pipe from the leachate inlet at the bottom of the leachate drain pipe is the height for controlling the lowest leachate level in the well pipe.

4. A method for an integrated garbage heap well to achieve automatic drainage, gas collection, and repair according to claim 1, characterized in that The leachate drainage valve is installed at the liquid outlet end of the leachate drain pipe. The outlet of the leachate drain pipe is connected to a gas-liquid separation valve. The landfill gas collection valve is installed at the gas outlet of the landfill gas collection pipe. The gas inlet of the landfill gas collection pipe passes through the flange and extends into the well pipe, and the position is lower than the lower edge of the flange to ensure the collection efficiency of the landfill gas.

5. A method for realizing automatic drainage, gas collection and repair of an integrated garbage landfill well according to claim 1, characterized in that The air supply control signal output end of the automatic control system is connected to the start and stop signal receiving ends of the high-pressure air pump through a data line. The detection signal output end of the water level monitoring probe is connected to the liquid level signal receiving end of the automatic control system, and the automatic control system controls the operation of the high-pressure air pump according to the detection signal of the water level monitoring probe.

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