A two-stage biological oxidation gas guide well

Abstract

The application belongs to the technical field of environment, and discloses a two-stage biological oxidation gas guide well, which comprises a well wall structure, a well pipe structure, a filling structure, a biological cover layer structure and a leachate irrigation structure; the well wall structure comprises a reinforced stone cage net, the reinforced stone cage net is arranged in a well hole of a garbage pile body, a first geotextile screen is fixedly installed on the outer side of the reinforced stone cage net, and a concrete base is arranged at the bottom of the outer wall of the reinforced stone cage net. The two-stage biological oxidation gas guide well is formed by the biological filling layer and the biological cover layer structure, the first-stage biological filling layer maintains moisture by using the percolate in the interior of the pile body, the second-stage biological cover layer maintains moisture by the specially arranged leachate irrigation structure, the purpose of in-situ control of landfill gas is achieved, the problem that landfill gas cannot be treated in a small landfill is solved, the two-stage biological oxidation reduces the emission amount of landfill gas, and the method is suitable for the landfill in operation and has the advantages of low cost and easy operation.

Description

Technical Field

[0001] This invention belongs to the field of environmental technology, specifically a two-stage biological oxidation gas-conducting well. Background Technology

[0002] Landfills release large amounts of landfill gas during operation and for a considerable period after completion. A significant portion of this gas is released into the surrounding environment through fugitive emissions, causing pollution. The main component of landfill gas is methane, a major greenhouse gas and a precursor to ozone. Reducing methane emissions is therefore crucial. Controlling landfill gas emissions can be approached from several angles: First, methane reduction can be achieved by modifying landfill technology during the initial landfilling process. However, some landfill gas will still escape into the environment through the cover layer. Second, landfill gas collection systems can be used to collect the gas. Additionally, modifying the cover layer can also reduce the emission of methane and other landfill gases. This can be achieved by enhancing the oxidation of landfill gas during and after landfilling. However, this method only treats the gas at the landfill surface; the gas in the gas delivery wells remains untreated, thus requiring improvement. Summary of the Invention

[0003] The purpose of this invention is to provide a two-stage bio-oxidation gas-conducting well to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a two-stage biological oxidation gas-conducting well, comprising:

[0005] Wellbore structure, well casing structure, filling structure, biological cover structure, and leachate irrigation structure;

[0006] The well wall structure includes a reinforced gabion mesh, which is installed inside the well hole of the garbage pile. A first geotextile filter is fixedly installed on the outside of the reinforced gabion mesh, and a concrete base is provided at the bottom of the outer wall of the reinforced gabion mesh.

[0007] The well casing structure is located inside the well wall structure and includes a vertical gas guide pipe. The vertical gas guide pipe is located at the center of the well wall structure, and both the upper and lower ends of the vertical gas guide pipe are provided with end caps.

[0008] A biological packing layer is provided between the wellbore structure and the well casing structure;

[0009] The biological cover structure is located above the well casing structure and consists of a coarse-grained slag layer, a fine-grained slag layer, a biomass layer, a soil layer, an HDPE membrane, and a second geotextile filter, stacked together, with an overall thickness of not less than 500 mm and a diameter of not less than 2 m.

[0010] The leachate irrigation structure is located above the bio-covered layer structure and includes a leachate irrigation main pipe. The bottom of the leachate irrigation main pipe is fixedly connected to a leachate irrigation branch pipe. The bottom of the leachate irrigation branch pipe extends into the bio-covered layer. Valves are provided on both the leachate irrigation branch pipe and the leachate irrigation main pipe.

[0011] Preferably, the vertical air guide pipe is a pipe with a diameter of 100mm, with a solid wall pipe for the upper 1m and a perforated pipe for the remaining part, and the perforation rate of the perforated pipe is not less than 3%.

[0012] Preferably, in the biological cover layer structure, the coarse-grained slag layer is located in the lower layer with a thickness of 100-150 mm, the fine-grained slag layer is located in the middle layer with a thickness of 100-150 mm, and the biomass layer is located in the upper layer with a thickness of 180-200 mm.

[0013] Preferably, the biomass layer is made of a mixture of manure and sawdust, wherein the manure accounts for 40% to 50% of the total volume, and the porosity of the biomass layer is greater than 50%.

[0014] Preferably, the stacking order of the biological cover layer structure from bottom to top is as follows: second geotextile filter, HDPE membrane, coarse-grained slag layer, fine-grained slag layer, HDPE membrane, biomass layer, second geotextile filter, HDPE membrane and soil layer. When laying the HDPE membrane, an air-guiding channel is reserved. The width of the air-guiding channel at the top is 25-30cm, and the width at the middle and bottom is 15-20cm.

[0015] Preferably, the HDPE membrane is a 1mm thick smooth membrane, and the second geotextile filter has a specification of not less than 200g / m². 2 .

[0016] Preferably, the diameter of the leachate irrigation main pipe is 63 mm, the diameter of the leachate irrigation branch pipe is 25 mm, and the leachate irrigation branch pipe adopts the form of bottom perforation and is sealed at the end with a screw cap.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention utilizes a two-stage bio-oxidation process. First, a biological packing layer is installed around the wellbore, buried inside the landfill body, where methane undergoes a first-stage bio-oxidation reaction before entering the well. Second, a biological covering layer is installed around the top of the wellbore, where methane undergoes a second-stage bio-oxidation reaction before exiting the well. This creates a two-stage bio-oxidation well composed of the biological packing layer and the biological covering layer. The first-stage biological packing layer retains moisture using leachate from inside the landfill body, while the second-stage biological covering layer retains moisture through a specially designed leachate irrigation structure. This ultimately achieves in-situ control of landfill gas, solving the problem of landfill gas being unmanageable in small landfills. The two-stage bio-oxidation process reduces landfill gas emissions, and this method is applicable to operating landfills, offering advantages such as low cost and ease of operation. Attached Figure Description

[0019] Figure 1 This is a schematic cross-sectional view of the two-stage bio-oxidation gas-conducting well of the present invention;

[0020] Figure 2 This is a schematic plan view of the biomass layer in the two-stage biological oxidation gas-conducting well of the present invention.

[0021] In the diagram: 101, First geotextile screen; 102, Reinforced gabion mesh; 103, Concrete base; 201, End cap; 202, Vertical air duct; 3, Biological filler layer; 401, Coarse-grained slag layer; 402, Fine-grained slag layer; 403, Biomass layer; 404, Soil layer; 405, HDPE membrane; 406, Second geotextile screen; 407, Air duct; 501, Leachate irrigation branch pipe; 502, Leachate irrigation main pipe; 503, Valve. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figures 1 to 2 As shown, an embodiment of the present invention provides a two-stage bio-oxidation gas-conducting well, comprising:

[0024] Wellbore structure, well casing structure, filling structure, biological cover structure, and leachate irrigation structure;

[0025] The well wall structure includes a reinforced gabion mesh 102, which is installed in the well hole of the garbage pile. A first geotextile filter 101 is fixedly installed on the outside of the reinforced gabion mesh 102, and a concrete base 103 is provided at the bottom of the outer wall of the reinforced gabion mesh 102.

[0026] The well casing structure is located inside the well wall structure and includes a vertical gas guide pipe 202. The vertical gas guide pipe 202 is located at the center of the well wall structure, and end caps 201 are provided at both the upper and lower ends of the vertical gas guide pipe 202.

[0027] A biological packing layer 3 is provided between the wellbore structure and the well casing structure;

[0028] The biological cover structure is located above the well casing structure and consists of a coarse-grained slag layer 401, a fine-grained slag layer 402, a biomass layer 403, a soil layer 404, an HDPE membrane 405, and a second geotextile filter 406 stacked together. The overall thickness is not less than 500 mm and the diameter is not less than 2 m.

[0029] The leachate irrigation structure is located above the bio-covered structure and includes a leachate irrigation main pipe 502. The bottom of the leachate irrigation main pipe 502 is fixedly connected to a leachate irrigation branch pipe 501. The bottom of the leachate irrigation branch pipe 501 extends into the bio-covered layer. Both the leachate irrigation branch pipe 501 and the leachate irrigation main pipe 502 are equipped with valves 503.

[0030] The gas well employs a two-stage biological oxidation reaction: a biological packing layer is installed around the well body buried inside the pile body, where methane undergoes the first stage of biological oxidation before entering the gas well; and a biological covering layer is installed around the top wellhead, where methane undergoes the second stage of biological oxidation before exiting the gas well.

[0031] like Figure 1 and Figure 2 As shown, the vertical air guide pipe 202 uses a pipe with a diameter of 100mm. The upper 1m uses a solid wall pipe, and the rest uses a perforated pipe with an opening rate of not less than 3%.

[0032] The design, with a perforation rate of no less than 3%, facilitates gas flow.

[0033] like Figure 1 As shown, in the biomass cover structure, the coarse-grained slag layer 401 is located in the lower layer with a thickness of 100~150mm, the fine-grained slag layer 402 is located in the middle layer with a thickness of 100~150mm, and the biomass layer 403 is located in the upper layer with a thickness of 180~200mm.

[0034] Among them, by using a biofilm of microbial communities such as methane-oxidizing bacteria that have the function of degrading methane, and then using a coarse-particle slag layer 401, a fine-particle slag layer 402, and a biomass layer 403, a good methane degradation effect can be achieved.

[0035] like Figure 1 and Figure 2 As shown, the biomass layer 403 is made of a mixture of manure and sawdust, with manure accounting for 40% to 50% of the total volume and the porosity of the biomass layer 403 being greater than 50%.

[0036] The design with a larger porosity can increase air permeability and drainage, thereby improving the stability and durability of the biomass layer 403.

[0037] like Figure 1 As shown, the stacking order of the biomass cover structure from bottom to top is as follows: second geotextile filter 406, HDPE membrane 405, coarse-grained slag layer 401, fine-grained slag layer 402, HDPE membrane 405, biomass layer 403, second geotextile filter 406, HDPE membrane 405 and soil layer 404. When laying HDPE membrane 405, air channels 407 are reserved. The width of air channels 407 at the top is 25~30cm, and the width at the middle and bottom is 15~20cm.

[0038] Among them, the gas channel 407 serves as the sole gas channel to increase the reaction time of the gas within the biomass cover and to better handle landfill gas.

[0039] like Figure 1 As shown, the HDPE membrane 405 uses a 1mm thick smooth membrane, and the second geotextile filter 406 has a specification of not less than 200g / m². 2 .

[0040] The second geotextile screen acts as a reverse filter, and the HDPE membrane ensures that the landfill gas has a sufficiently long residence time to react within the biomass cover.

[0041] like Figure 1 and Figure 2 As shown, the diameter of the leachate irrigation main pipe 502 is 63mm, and the diameter of the leachate irrigation branch pipe 501 is 25mm. The leachate irrigation branch pipe 501 adopts the form of bottom perforation and is sealed at the end with a screw cap.

[0042] The design of the leachate irrigation branch pipe 501 and the leachate irrigation main pipe 502 allows the biological cover structure to retain moisture. Example

[0043] Experimental group:

[0044] The well wall structure is located inside the well hole of the garbage pile, with a diameter of 1000mm. It is wrapped with a second geotextile filter 406 of 200g / m2 on the outside. A 500mm×500mm concrete base 103 is fixed to it on both sides below the reinforced gabion mesh 102. A vertical air guide pipe 202 with a diameter of 100mm is located in the middle of the well wall structure. The upper 1m is a solid wall pipe, and the rest is a perforated pipe with an opening rate of 3%. The two ends of the vertical air guide pipe 202 are sealed with end caps 201.

[0045] The filling structure is located between the second geotextile filter 406 and the vertical air duct 202. The filling material is crushed stone with a particle size of 20-40mm. The crushed stone needs to be coated with microbial flora such as methane-oxidizing bacteria that have the function of degrading methane. The well wall structure, well pipe structure and filling structure gradually increase in height as the garbage pile increases. The well pipe structure is 400mm higher and is sealed with end cap 201.

[0046] Above the waste pile, within a 2m diameter area centered on the well pipe structure, a 1mm HDPE membrane 405 is used to separate it from the waste pile covering layer, with a height of 400mm. In this area, from top to bottom, a coarse-grained slag layer 401 (5-20mm diameter, 100mm thick) and a fine-grained slag layer 402 (less than 5mm diameter, 100mm thick) are successively filled. A biomass layer 403, consisting of a mixture of manure and sawdust (manure comprising 40% of the volume), is 200mm thick. Below the slag layer, a second geotextile filter 406 and an HDPE membrane 405 are laid sequentially, with a 20cm air passage 407 reserved. An HDPE membrane 405 is laid between the slag layer and the biomass layer 403, with a reserved air passage. The well casing 407 has a channel length of 20cm. Above the biomass layer 403, a second geotextile filter 406 and an HDPE membrane 405 are laid in sequence, with a reserved air channel 407 of 30cm. At this point, the height of the well casing structure, the slag layer, and the HDPE membrane 405 wrapped on the outside are consistent. Then, loess is used to cover the casing with a thickness of 100mm. In addition, the slag and biomass layer 403 need to be used after being covered by microbial colonies. A leachate irrigation main pipe 502 with a diameter of 65mm is set above the loess cover layer, and four leachate irrigation branch pipes 501 are branched into the biomass cover layer. The diameter of the leachate irrigation branch pipes 501 is 25mm. The leachate irrigation branch pipes 501 in the biomass cover layer are perforated at the bottom and sealed at the end with a screw cap.

[0047] Control group:

[0048] The well wall structure is located inside the well hole of the garbage dump, with a diameter of 1000mm. It is wrapped with a layer of 200g / m2 second geotextile filter 406 on the outside. A 500mm×500mm concrete base 103 is fixed on both sides below the reinforced gabion mesh 102. A vertical air guide pipe 202 with a diameter of 100mm is placed in the center of the well wall structure. The vertical air guide pipe 202 is a perforated pipe. The space between the reinforced gabion mesh 102 and the vertical air guide pipe 202 is filled with crushed stone with a particle size of 20~40mm.

[0049] The methane content in the gas above the experimental group and the control group was compared.

[0050] Table 1 Comparison of methane content between the experimental group and the control group

[0051] methane content in the experimental group (%) control group methane content % 304d 2.0 33.8 Article 306d 2.6 39.3 Article 309d 1.7 42.4 Section 311d 1.4 31.4 316d 2.2 38.2 318d 2.1 42.3 320d 1.7 41.7 323d 2.3 43.1 325d 4.5 30.5 331d 3.3 47.5 337th 4.4 30.6 339d 4.8 37.1 344d 4.3 36.0 346d 2.8 38.7 351d 4.6 38.2 353d 4.2 35.3 358th 3.7 37.0 Chapter 362d 2.8 32.7

[0052] Compared to the control group, the two-stage bio-oxidation gas wells in the experimental group showed better degradation effect on methane gas.

[0053] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A two-stage biological oxidation gas-conducting well, characterized in that: Including: Wellbore structure, well casing structure, filling structure, biological cover structure, and leachate irrigation structure; The well wall structure includes a reinforced gabion mesh (102), which is installed in the well hole of the garbage pile. A first geotextile filter mesh (101) is fixedly installed on the outside of the reinforced gabion mesh (102), and a concrete base (103) is provided at the bottom of the outer wall of the reinforced gabion mesh (102). The well pipe structure is located inside the well wall structure and includes a vertical gas guide pipe (202). The vertical gas guide pipe (202) is located at the center of the well wall structure, and both the upper and lower ends of the vertical gas guide pipe (202) are provided with end caps (201). The filling structure includes a biological filler layer (3), which is located between the wellbore structure and the well casing structure; The biological cover structure is located above the well pipe structure and is composed of a coarse-grained slag layer (401), a fine-grained slag layer (402), a biomass layer (403), a soil layer (404), an HDPE membrane (405), and a second geotextile filter (406). The overall thickness is not less than 500 mm and the diameter is not less than 2 m. The leachate irrigation structure is located above the bio-covered layer structure and includes a leachate irrigation main pipe (502). The bottom of the leachate irrigation main pipe (502) is fixedly connected to a leachate irrigation branch pipe (501). The bottom of the leachate irrigation branch pipe (501) extends into the bio-covered layer. Both the leachate irrigation branch pipe (501) and the leachate irrigation main pipe (502) are equipped with valves (503). The stacking order of the biological cover structure from bottom to top is as follows: second geotextile filter (406), HDPE membrane (405), coarse-grained slag layer (401), fine-grained slag layer (402), HDPE membrane (405), biomass layer (403), second geotextile filter (406), HDPE membrane (405) and soil layer (404). When laying the HDPE membrane (405), an air channel (407) is reserved. The width of the air channel (407) at the top is 25~30cm, and the width at the middle and bottom is 15~20cm. The HDPE membrane (405) is a smooth membrane with a thickness of 1 mm, and the second geotextile filter (406) has a specification of not less than 200 g / m2.

2. The two-stage biological oxidation gas-conducting well according to claim 1, characterized in that: The vertical air guide pipe (202) is a pipe with a diameter of 100mm. The upper 1m is a solid wall pipe, and the rest is a perforated pipe with an opening rate of not less than 3%.

3. The two-stage biological oxidation gas-conducting well according to claim 1, characterized in that: In the biological cover structure, the coarse-grained slag layer (401) is located in the lower layer with a thickness of 100~150mm, the fine-grained slag layer (402) is located in the middle layer with a thickness of 100~150mm, and the biomass layer (403) is located in the upper layer with a thickness of 180~200mm.

4. The two-stage biological oxidation gas-conducting well according to claim 1, characterized in that: The biomass layer (403) is made of a mixture of manure and sawdust, wherein the manure accounts for 40% to 50% of the total volume, and the porosity of the biomass layer (403) is greater than 50%.

5. The two-stage biological oxidation gas-conducting well according to claim 1, characterized in that: The leachate irrigation main pipe (502) has a diameter of 63 mm, and the leachate irrigation branch pipe (501) has a diameter of 25 mm. The leachate irrigation branch pipe (501) is perforated at the bottom and sealed at the end with a screw cap.

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