Landfill gas guiding and discharging system for side slope of landfill

Abstract

The utility model relates to the technical field of sanitary landfill of household garbage, in particular to a landfill side slope landfill gas guiding and discharging system which comprises a gas collecting well, a gas guiding blind ditch and a connecting blind ditch, and the center of the gas collecting well is fixedly connected with an HDPE gas guiding pipe. The gas guide blind ditch is arranged in the irregular area, the side slope area or the corner area of the landfill, and the connecting blind ditch is connected with the nearest gas collecting well, so that the influence of the gradient of the side slope area on the drilling depth of the conventional gas collecting well is eliminated, and the gas guide effect of the landfill gas in the side slope area is greatly enhanced; meanwhile, the defect that the coverage range of a conventional gas collecting well is limited can be overcome, the gas guide blind ditches can be flexibly arranged according to on-site topography, slope gradient changes and the like, the guide and drainage coverage range is large, the whole device is easy to construct and reliable in structure, and the risk that the conventional gas collecting well damages a slope bottom anti-seepage structure is reduced; and safe and stable operation of the landfill gas guiding and discharging system is facilitated.

Description

Technical Field

[0001] This application relates to the technical field of sanitary landfill for municipal solid waste, and in particular to a landfill slope filling gas drainage system. Background Technology

[0002] Landfill gas is the gas produced by the anaerobic digestion and degradation of a large amount of organic matter contained in municipal solid waste that has been piled up or landfilled. Its main components are methane (30%~40%) and carbon dioxide (40%~50%), as well as small amounts of ammonia, hydrogen sulfide, nitrogen and trace amounts of volatile organic compounds (including chlorinated hydrocarbons, methanethiol, benzene series, etc.). Landfill gas is collected through gas collection wells, gas collection pipes and fans and transported to the end for combustion power generation or centralized combustion treatment by setting up flare combustion devices to ensure the safety of landfill gas.

[0003] Regarding the aforementioned technologies, the inventors have discovered the following defects: In the prior art, the distance between the bottom of the well and the bottom of the landfill should not be less than 5m. For the landfill slope area, due to the influence of the slope gradient, the gas conduction effect will be poor. At the same time, the landfill boundary shape is irregular, and the gas gathering well is difficult to cover the irregular or corner areas of the landfill, which poses a risk of damaging the site's anti-seepage structure. Utility Model Content

[0004] To enhance the drainage effect of landfill gas in irregular areas, slope areas, or corner areas of landfills and overcome the problems of using gas collection wells alone for drainage, this application provides a landfill slope drainage system.

[0005] This application provides a landfill slope gas drainage system, which adopts the following technical solution: it includes a gas collection well, a gas drainage blind ditch and a connecting blind ditch. A gas drainage pipe is fixedly connected to the center of the gas collection well. A pipe connector is fixedly connected to the bottom of the gas drainage pipe. A perforated pipe is fixedly connected to the bottom of the pipe connector. A wire mesh is provided on the outer wall of the perforated pipe. Graded pebbles are filled between the inner wall of the wire mesh and the outer wall of the perforated pipe. A plug is fixedly connected to the side of the gas collection well away from the pipe connector.

[0006] Optionally, the outer wall of the gas-conducting pipe is in contact with compacted clay, and the top of the compacted clay is in contact with a covering impermeable structural layer.

[0007] Optionally, the compacted clay is fixedly connected to the geotextile surrounding the air guide well, the geotextile surrounding the air guide well is in contact with the garbage pile, and the bottom of the garbage pile is in contact with the slope and the bottom seepage prevention structure of the reservoir.

[0008] Optionally, the bottom of the slope and reservoir bottom seepage prevention structure is in contact with the reservoir bottom foundation layer, and the top of the covering seepage prevention structure layer is in contact with the covering structure layer.

[0009] Optionally, the gas guide pipe is fixedly connected to a detection sampling port, the side of the connecting blind trench away from the pipe connector is fixedly connected to the side of the gas guide blind trench near the connecting blind trench, and the side of the connecting blind trench away from the gas guide blind trench is fixedly connected to the gas gathering well.

[0010] Optionally, both the air-guiding blind ditch and the connecting blind ditch are filled with graded pebbles, and both the outer walls of the air-guiding blind ditch and the connecting blind ditch are fixedly connected with a second type of perimeter geotextile. The side of the air-guiding blind ditch away from the connecting blind ditch is fixedly connected with a first type of perimeter geotextile.

[0011] Optionally, the side of the connecting blind drain away from the gas-conducting blind drain is fixedly connected to the perforated pipe, the solid gas-conducting pipe is fixedly connected to a gas-conducting branch pipe, the side of the gas-conducting branch pipe away from the solid gas-conducting pipe is fixedly connected to a gas-conducting main pipe, the gas-conducting main pipe is fixedly connected to a simple condensate drainage device, and the side of the gas-conducting main pipe near the simple condensate drainage device is fixedly connected to a landfill gas treatment device.

[0012] In summary, this application includes the following beneficial technical effects:

[0013] 1. This utility model, by incorporating components such as gas collection wells, gas guiding blind trenches, and connecting blind trenches, eliminates the influence of slope gradient on the drilling depth of conventional gas collection wells by setting up gas guiding blind trenches in irregular areas, slope areas, or corner areas of landfills, and connecting the blind trenches to the nearest gas collection wells. This greatly enhances the gas guiding effect of landfill gas in slope areas, while also compensating for the limited coverage of conventional gas collection wells. The gas guiding blind trenches can be flexibly routed according to the site topography and irregular orientation, providing a large guiding coverage area. The entire device is simple to construct, has a reliable structure, reduces the risk of conventional gas collection wells damaging the anti-seepage structure at the bottom of the slope, and is conducive to the safe and stable operation of the landfill gas guiding system. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the layout structure of the landfill slope air guiding device in the embodiments of this application;

[0015] Figure 2 This is a schematic diagram of the blind drain structure in an embodiment of this application;

[0016] Figure 3 This is a schematic diagram of the landfill gas drainage system in an embodiment of this application.

[0017] Attached reference numerals: 1. Gas collection well; 101. Sampling port; 102. Plug; 103. Gas guide branch pipe; 104. Pipe connector; 105. Perforated pipe; 106. Compacted clay; 107. Geotextile surrounding the gas guide well; 108. Graded gravel; 109. Wire mesh; 110. Solid gas guide pipe; 2. Covering structure layer; 3. Covering impermeable structure layer; 4. Garbage pile; 5. Gas guide blind ditch; 501. Geotextile surrounding the blind ditch (first layer); 6. Connecting blind ditch; 601. Geotextile surrounding the blind ditch (second layer); 7. Slope and bottom impermeable structure; 8. Bottom foundation layer; 9. Gas guide main pipe; 10. Simple condensate drainage device; 11. Landfill gas treatment device. Detailed Implementation

[0018] The following is in conjunction with the appendix Figures 1-3 This application will be further described in detail below. The technical solutions in the embodiments of this application will be clearly described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0019] This application discloses a landfill slope embankment gas drainage system. For example... Figure 1 As shown, it includes a gas gathering well 1, a gas guiding blind trench 5 and a connecting blind trench 6. The effective gas gathering radius of the gas gathering well 1 is about 20~25m, and the distance from the bottom seepage prevention structure layer is not less than 5m. A gas guiding solid pipe 110 is fixedly connected to the center of the gas gathering well 1, and a pipe connector 104 is fixedly connected to the bottom of the gas guiding solid pipe 110.

[0020] In this embodiment, a perforated pipe 105 is fixedly connected to the bottom of the pipe connector 104. The perforated pipe 105 has an opening size of 40×20mm, with six holes evenly distributed in each layer and a spacing of 200mm. A wire mesh 109 is provided on the outer wall of the perforated pipe 105. Graded pebbles 108 are filled between the inner wall of the wire mesh 109 and the outer wall of the perforated pipe 105. The wire mesh 109 is filled with graded pebbles 108 with a particle size of Ф20~50. A plug 102 is fixedly connected to the side of the gas gathering well 1 away from the pipe connector 104.

[0021] Please see Figure 1 , Figure 3As shown, the side of the connecting blind drain 6 away from the gas-guiding blind drain 5 is fixedly connected to the perforated pipe 105. The solid gas-guiding pipe 110 is fixedly connected to the gas-guiding branch pipe 103. The side of the gas-guiding branch pipe 103 away from the solid gas-guiding pipe 110 is fixedly connected to the gas-guiding main pipe 9. The gas-guiding branch pipe 103 is made of HDPE pipe and is connected to the exhaust pipe of each gas collecting well 1, with a slope of not less than 2%. The gas-guiding main pipe 9 is made of HDPE pipe and is connected to each gas-guiding branch pipe 103, with a slope of not less than 2%. The gas-guiding main pipe 9 is fixedly connected to the condensate simple drainage device 10. The side of the gas-guiding main pipe 9 near the condensate simple drainage device 10 is fixedly connected to the landfill gas treatment device 11.

[0022] Please see Figure 1 As shown, the outer wall of the air-conducting pipe 110 is in contact with compacted clay 106, and the top of the compacted clay 106 is in contact with the covering impermeable structure layer 3. The compacted clay 106 and the covering impermeable structure layer 3 are connected to maintain good sealing. 300g / m2 geotextile is set around the compacted clay 106.

[0023] Please see Figure 1 As shown, the gas guide pipe 110 is fixedly connected to a detection sampling port 101. The setting of the detection sampling port 101 allows the device to determine whether landfill gas exists or passes through by analyzing the gas composition and pressure in the gas guide pipe. The side of the connecting blind ditch 6 away from the pipe connector 104 is fixedly connected to the side of the gas guide blind ditch 5 near the connecting blind ditch 6. The cross-sectional dimensions of the gas guide blind ditch 5 and the connecting blind ditch 6 are 0.5m×0.5m or 0.8m×0.8m, which are determined by comprehensively considering the gas production rate based on the source of landfill waste, the content and composition of organic matter, and the landfill cycle. The side of the connecting blind ditch 6 away from the gas guide blind ditch 5 is fixedly connected to the gas collection well 1.

[0024] Please see Figure 1 As shown, the outer wall of the compacted clay 106 is fixedly connected to the geotextile 107 surrounding the air guide well. The outer wall of the geotextile 107 surrounding the air guide well is in contact with the garbage pile 4. The bottom of the garbage pile 4 is in contact with the slope and the bottom seepage prevention structure 7.

[0025] Please see Figure 1 As shown, both the air-conducting blind ditch 5 and the connecting blind ditch 6 are filled with graded pebbles 108. The outer walls of both the air-conducting blind ditch 5 and the connecting blind ditch 6 are fixedly connected with the outer perimeter geotextile 601. The side of the air-conducting blind ditch 5 away from the connecting blind ditch 6 is fixedly connected with the outer perimeter geotextile 501.

[0026] Please see Figure 1 , Figure 2 As shown, the bottom of the slope and reservoir bottom seepage prevention structure 7 is in contact with the reservoir bottom foundation layer 8, and the top of the seepage prevention structure layer 3 is in contact with the covering structure layer 2.

[0027] The implementation principle of a landfill slope gas drainage system according to an embodiment of this application is as follows: A gas drainage blind ditch 5 is installed along irregular areas, slope areas, or corner areas of the landfill, located below the cover structure layer 2 and the cover impermeable structure layer 3. The blind ditch is filled with Ф20~50mm graded pebbles 108, and a 300g / m² geotextile is placed around the outer perimeter to wrap the graded pebbles 108. Based on factors such as the source of landfill waste, organic matter content and composition, and landfill cycle, and considering the gas production rate, the following principle is applied: The cross-sectional dimensions of the gas-guiding blind ditch 5 and the connecting blind ditch 6 are preferably 0.5m×0.5m, 0.8m×0.8m, or 1m×1m. The effective gas collection radius of the gas collection well 1 is approximately 20~25m, and the distance from the bottom seepage-proof structure layer is not less than 5m. The gas collection well 1 is connected to the gas-guiding blind ditch 5 through the connecting blind ditch 6, which is connected to the lower half of the gas collection well 1. The landfill gas generated by the waste pile 4 is collected through the gas collection well 1, the gas-guiding blind ditch 5, and the connecting blind ditch 6. The landfill gas collected by the gas-guiding blind ditch 5 and the connecting blind ditch 6 passes through the gas collection well 1, the gas-guiding blind ditch 5, and the connecting blind ditch 6 in sequence. The gas blind drain 5, connecting blind drain 6, lower half of the gas collecting well 1 (geotextile, wire mesh 109, graded pebbles 108) enter the perforated pipe 105 of the lower section of the HDPE gas guide pipe, where it merges with the landfill gas collected within the effective gas collecting range of the gas collecting well 1. The gas is then discharged through the gas guide branch pipe 103 to the gas guide main pipe 9, and finally enters the landfill gas treatment device 11. Depending on the landfill gas production scale, different treatment processes can be selected for landfill gas treatment. When the gas production scale is large, combustion power generation for resource recovery and utilization is preferred; when the gas production scale is small, other methods can be used... The flare combustion device centrally combusts and treats the landfill gas to ensure safe disposal. The gas pipeline is divided into gas branch pipes and gas main pipes. The gas branch pipes 103 are made of HDPE pipes and are connected to the exhaust pipes of each gas collection well 1, with a slope of not less than 2%. The gas main pipe 9 is made of HDPE pipes and is connected to each gas branch pipe 103, with a slope of not less than 2%. A simple condensate drainage device 10 is set at the lowest point of the gas main pipe 9. See the patent for details: A simple condensate drainage device for landfill gas and its use in a municipal solid waste landfill.

[0028] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A landfill slope landfill gas drainage system, comprising a gas collection well (1), a gas drainage blind drain (5), and a connecting blind drain (6), characterized in that: The gas gathering well (1) is fixedly connected to a gas guide pipe (110) at its center. A pipe connector (104) is fixedly connected to the bottom of the gas guide pipe (110). A perforated pipe (105) is fixedly connected to the bottom of the pipe connector (104). A wire mesh (109) is provided on the outer wall of the perforated pipe (105). Graded pebbles (108) are filled between the inner wall of the wire mesh (109) and the outer wall of the perforated pipe (105). A plug (102) is fixedly connected to the side of the gas gathering well (1) away from the pipe connector (104).

2. The landfill slope gas drainage system according to claim 1, characterized in that: The outer wall of the gas-conducting pipe (110) is in contact with compacted clay (106), and the top of the compacted clay (106) is in contact with a covering impermeable structural layer (3).

3. A landfill slope embankment gas drainage system according to claim 2, characterized in that: The compacted clay (106) is fixedly connected to the geotextile (107) around the gas well. The geotextile (107) around the gas well is in contact with the garbage pile (4). The bottom of the garbage pile (4) is in contact with the slope and the bottom seepage prevention structure (7).

4. A landfill slope embankment gas drainage system according to claim 3, characterized in that: The bottom of the slope and reservoir bottom seepage prevention structure (7) is in contact with the reservoir bottom foundation layer (8), and the top of the covering seepage prevention structure layer (3) is in contact with the covering structure layer (2).

5. A landfill slope embankment gas drainage system according to claim 2, characterized in that: The gas guide pipe (110) is fixedly connected to a detection sampling port (101). The side of the connecting blind trench (6) away from the pipe connector (104) is fixedly connected to the side of the gas guide blind trench (5) close to the connecting blind trench (6). The side of the connecting blind trench (6) away from the gas guide blind trench (5) is fixedly connected to the gas gathering well (1).

6. A landfill slope embankment gas drainage system according to claim 1, characterized in that: Both the air-guiding blind ditch (5) and the connecting blind ditch (6) are filled with graded pebbles (108). The outer walls of both the air-guiding blind ditch (5) and the connecting blind ditch (6) are fixedly connected with the second type of perimeter geotextile (601). The side of the air-guiding blind ditch (5) away from the connecting blind ditch (6) is fixedly connected with the first type of perimeter geotextile (501).

7. A landfill slope embankment gas drainage system according to claim 5, characterized in that: The side of the connecting blind drain (6) away from the gas-guiding blind drain (5) is fixedly connected to the perforated pipe (105). The solid gas-guiding pipe (110) is fixedly connected to the gas-guiding branch pipe (103). The side of the gas-guiding branch pipe (103) away from the solid gas-guiding pipe (110) is fixedly connected to the gas-guiding main pipe (9). The gas-guiding main pipe (9) is fixedly connected to the condensate simple drainage device (10). The side of the gas-guiding main pipe (9) close to the condensate simple drainage device (10) is fixedly connected to the landfill gas treatment device (11).

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