A landfill method with low leachate production and rapid stabilization

Abstract

The present invention relates to a landfill method with low leachate production and rapid and stable stabilization of garbage, and relates to the technical field of garbage landfilling. The oxygen carried by the initial state of the incoming garbage is used as the initial oxygen demand for subsequent aerobic degradation; a vertical air duct array connected to the bottom leachate drainage pipe is arranged at intervals in the garbage landfill storage area, and a non-powered air induction device is installed at intervals at the top of the vertical air duct array, and the ventilation mode inside the garbage landfill heap is strengthened by the non-powered air induction device; the oxygen influence range of the vertical air duct in the garbage landfill heap is used as the landfill unit of the vertical air duct, each vertical air duct is located at the center of its respective landfill unit, and the ratio of the diameter of the vertical air duct to the diameter of its oxygen influence range is (1:150) to (1:50); the surface of the garbage landfill heap is covered with a film to isolate the infiltration of external liquids, thereby reducing leachate. This method reduces the total production of garbage leachate during the entire landfill cycle to 0.1 m3 / ton of landfilled garbage.

Description

Technical Field

[0001] The present invention relates to the technical field of landfill technology, and more specifically, to a landfill method with low leachate production and rapid and stable stabilization of garbage, especially a method for low-cost harmless treatment and disposal of domestic garbage in rural areas. Background Art

[0002] The generation of garbage in rural areas of our country has obvious characteristics of "low output, strong dispersion, and local outbreaks". At the same time, in rural areas, whether it is domestic garbage or products such as composting and incineration, they all need to enter the landfill for treatment. From the perspective of existing urban domestic waste sanitary landfill methods, it is not a suitable choice to build large-scale landfills to handle rural garbage. At the same time, the treatment of secondary pollution in sanitary landfills is difficult, mainly manifested as a large amount of landfill leachate production, high pollution load, and a large amount of landfill gas production. For rural areas, the unbalanced economic development greatly restricts the implementation of traditional sanitary landfills for garbage. At the same time, there are a series of complex problems such as high leachate treatment costs and difficult treatment in the end-treatment of landfilled garbage, which further increases the difficulty of rural garbage treatment. Therefore, it is necessary to develop a landfill treatment and disposal method with low leachate production to achieve low-cost harmless landfill of garbage.

[0003] Prior Art 1: The Chinese invention patent "A Recycling Type Landfill and Landfill Method" (Patent No. 201710743356.8) mainly introduces a landfill implementation process. By dividing the landfill into multiple areas with different functions, each area is responsible for specific treatment of the garbage, and at the same time, artificial intervention is added to make the garbage be landfilled cyclically between each landfill functional area until the garbage is stabilized. However, in the process of landfill, there are garbage transposition and leachate recirculation measures in this method, which directly increase the operating cost of this method and have economic inadaptability in the treatment of rural garbage. This method also requires compaction of the landfilled garbage and does not have effective ventilation facilities, making it difficult to achieve passive diffusion of oxygen in the garbage mass.

[0004] Prior Art 2: The Chinese invention patent "A Landfill Method Based on the Principle of Bioreactor" (Patent No. 201110271924.1) designs a landfill method with reference to the principle of bioreactor. It mainly strengthens the microbial degradation process of the landfill by means of leachate recirculation and temperature control during the landfill process, improving the landfill gas production and leachate production levels. However, the method proposed in this patent involves complex leachate recirculation operations and temperature control means, with high energy consumption and operating costs, and is not suitable for popularization in rural areas with unbalanced economic development levels.

[0005] Prior Art 3: The Chinese invention patent "Landfill Method" (Patent No. 201610512005.1) solves the problem of excessive pollutant concentration in leachate during the landfill process and avoids the generation of acid accumulation phenomenon. It mainly proposes to alternately landfill the aerobically pretreated garbage and the original garbage to accelerate garbage degradation. At the same time, the aerobically pretreated garbage is used as a buffer layer for anaerobic landfill to reduce the pollution load of leachate. However, this method involves garbage pretreatment and alternate landfill, which is contrary to the characteristics of the invention patent that requires little pretreatment and is easy to operate, and is not suitable for rural areas with small garbage output.

[0006] In summary, there is currently a lack of a low-cost, easy-to-operate, and harmless garbage treatment and disposal method for rural areas. At the same time, the end products of other garbage treatment and disposal methods also need to enter the landfill. Therefore, what is lacking especially is a landfill method with low leachate production. Summary of the Invention

[0007] Aiming at the problem of difficult treatment of leachate in the existing sanitary landfill process for rural garbage, the landfill process of small units, micro-aerobic, low compaction density, and membrane-covered in the present invention is easy to operate and implement. At the same time, it can adapt to the characteristics of unsteady and generally low garbage output at the rural level. By changing the configuration of the landfill reservoir area to a connected grid type and changing the landfill treatment method to increase the proportion of oxygen in the gas phase composition in the garbage heap body, the focus of garbage biochemical degradation is shifted to aerobic degradation, realizing the landfill process of leachate reduction and garbage harmlessness.

[0008] According to the purpose of the present invention, a landfill method is provided. The oxygen carried by the incoming garbage in the initial state is used as the initial oxygen demand for subsequent aerobic degradation. A vertical air duct array connecting the bottom leachate drainage pipes is arranged at intervals in the landfill reservoir area. An unpowered air induction device is installed at intervals at the top of the vertical air duct array. The ventilation method inside the garbage landfill heap body is strengthened by the unpowered air induction device, and at the same time, the gas density gradient caused by the temperature difference between the inside and outside of the garbage landfill heap body is used as the driving force for natural gas convection to assist air induction.

[0009] Taking the oxygen influence range of the vertical air duct in the garbage landfill heap body as the landfill unit of the vertical air duct, each vertical air duct is located at the center of its respective landfill unit. The ratio of the diameter of the vertical air duct to the diameter of its oxygen influence range is (1:150) to (1:50). The oxygen influence range is the area within the aerobic radius centered on the vertical air duct.

[0010] The surface of the garbage landfill heap body is covered with a membrane to isolate the infiltration of external liquids, thereby reducing leachate.

[0011] Preferably, the depth of the landfill unit is 2 - 5m.

[0012] Preferably, the diameter of the landfill unit does not exceed 15 m.

[0013] Preferably, the compaction density of the incoming garbage in its initial state is 0.2-0.6 t / m 3 .

[0014] Preferably, the vertical air duct adopts a suction ventilation mode, and the power source is the negative pressure suction force generated by the unpowered draft device, so as to realize the transmission and retention of oxygen inside the pile body for aerobic degradation of garbage inside the pile body.

[0015] Preferably, the leachate drainage pipe is buried in the gravel filling layer at the bottom of the landfill body to realize a slow-release airflow path of atmosphere-air duct-gravel filling layer, thereby prolonging the residence time of the airflow inside the landfill body.

[0016] Preferably, the film used for the film covering is a polyethylene film.

[0017] Preferably, the leachate drainage pipe is located in the secondary blind ditch, and the leachate generated by each landfill unit is collected into the main blind ditch through the leachate drainage pipe in the secondary blind ditch, and then collected and flows into the leachate regulating pool for biochemical treatment, and is discharged after meeting the standards.

[0018] In general, the above technical solution conceived by the present invention has the following technical advantages compared with the prior art:

[0019] (1) The present invention develops a landfill method, which is a landfill method of small units, micro-aerobic, low compaction density, and membrane covering, and can be used for the landfill of rural domestic waste. The specific implementation content is as follows: a small unit landfill mode is adopted in the reservoir configuration of the landfill site, and the air flow turbulence area is increased during the air intake process between units to strengthen the mass transfer between phases, especially the oxygen diffusion and transmission process in small-volume spaces, thereby increasing the aerobic proportion of a single garbage heap body. During the landfill process, zoning operations are carried out; after the garbage enters the site, garbage spreading and mild compaction operations are carried out, that is, the porosity of the original garbage itself is maintained. On the one hand, the oxygen components carried by the garbage in its pores are preserved, which is convenient for the aerobic degradation of the garbage for a period of time after landfill. On the other hand, the relatively large porosity in the middle and late stages of garbage landfill provides an environmental basis for the air intake process of garbage landfill. Combined with a specific air intake method, it can keep the air continuously input into the interior of the garbage heap body to provide oxygen for the aerobic degradation of the garbage; after the unit landfill operation is completed, it is not necessary to provide forced air intake measures to the garbage heap body, but unpowered air intake devices are installed at intervals on the vertical air pipes between units. Thus, the ventilation mode inside the garbage heap body is mainly strengthened by the unpowered air intake devices at the top of the vertical air pipes, and at the same time, the gas density gradient caused by the temperature difference between the inside and outside of the garbage heap body is used as the driving force for natural gas convection to assist air intake, without additional power to supply oxygen to it, realizing the oxygen supply inside the heap body; three traditional membrane covering strategies of daily covering, intermediate covering, and final covering are adopted to isolate the outside water in real time, control the leachate production near the water content of the garbage itself, and assist in realizing low leachate production in garbage landfill. The garbage landfill will gradually stabilize, without generating leachate and landfill gas, and the present invention accelerates this stabilization process.

[0020] (2) The present invention discloses a landfill method for rural domestic waste with low leachate production and rapid stabilization. The implementation content of this method includes: centering on the vertical air ducts in the landfill body, subdividing the landfill area into small units with certain sizes, and using the oxygen carried in the initial state of the low-compaction landfill body as the initial oxygen demand for subsequent aerobic degradation. A vertical air duct array connected to the bottom leachate drainage pipe is arranged at intervals in the landfill area. The combined action of the airflow driven by the internal and external temperature difference and the natural environmental wind field injects oxygen into the landfill body, maintains the oxygen concentration level inside the landfill body to extend the aerobic degradation process, and accelerates the stabilization and harmlessness of the waste. The bottom of the landfill area filled with gravel enriches the leachate, and the natural ventilation effect of the air ducts can maintain the oxygen concentration at the bottom of the landfill area, strengthen the degradation of COD in the leachate, prevent the accumulation of ammonia nitrogen and organic macromolecules, and reduce the pollutant load of the leachate. The top is covered with a membrane (preferably an HDPE membrane) to prevent rainwater from seeping in and reduce the leachate production. At the same time, the arrangement of the air ducts connected at the bottom can also effectively degrade and disperse the malodorous gas and improve the sanitary environment of the landfill. The above-mentioned rapid stabilization landfill method can be used as the final landfill disposal process for waste or as an emergency landfill during the overhaul or operation and maintenance of a nearby waste incineration plant. When the initial moisture content of the incoming waste is about 65%, by adopting the small unit-self-induced air landfill mode of the present invention, the total leachate production of the waste during the entire landfill cycle can be reduced to 0.1 m 3 / ton of landfill waste, effectively reducing the operation cost and potential secondary pollution of small rural domestic waste landfills.

[0021] (3) In the present invention, the low leachate production comes from two parts of effects: isolating rainwater from entering the landfill body through membrane covering; in addition, the slow-release air circulation path of the atmosphere-air duct-gravel filling layer and the low-compaction density of the landfill body can maintain a good gas diffusion environment inside the landfill body, which is beneficial to maintaining the high-temperature time of the landfill body, further promoting the air convection caused by the temperature difference, and improving the water evaporation efficiency. By applying this landfill method, the leachate production of the waste can be reduced to less than 0.1 m 3 / ton of landfill waste.

[0022] (4) In the present invention, the leachate drainage pipe is buried in the gravel filling layer at the bottom of the landfill body. The gravel filling layer plays the role of gas storage and strengthening turbulence. Through the excavation of equally spaced triple-distributed pipe holes on the wall of the vertical air duct, it is convenient for air to diffuse into the landfill body and realize a larger aerobic area.

[0023] (5) In the present invention, during the air extraction process, the diameters of the leachate drainage pipes and the vertical air pipes should not be too large. Otherwise, excessive heat will be carried away by the heat convection due to the excessive air flow rate in the early and middle stages of landfill, further shortening the high-temperature period, which is not conducive to the aerobic degradation process and the evaporation of moisture in the landfill mass. Generally, the selection of the pipe diameter should correspond to the landfill unit size. The ratio of the diameter of the vertical air pipe to the landfill unit size is (1:150) - (1:50).

[0024] (6) In the present invention, during the landfill unit zoning operation, daily covering is carried out after each operation, intermediate covering is carried out after the landfill of a single unit is completed, and a three-stage covering strategy of final capping is adopted after the landfill site completes the landfill task, effectively isolating rainwater and achieving a low leachate production.

[0025] (7) In the present invention, during the garbage pretreatment stage, it is not necessary to carry out conventional compaction operations on the incoming garbage. The garbage can be spread and slightly compacted to maintain the bulk density of the garbage within the range of 0.2 - 0.6 t / m 3 , retaining the pores of the original garbage and the oxygen carried by itself in the early stage, realizing a micro-aerobic landfill environment for the garbage, and ensuring that sufficient oxygen can maintain the aerobic degradation process of garbage treatment throughout the early, middle and late stages of landfill.

[0026] (8) In the present invention, during the unpowered air extraction process, the unpowered air extraction device is installed at the top of the vertical air pipe of the corresponding unit, and it is preferably set at intervals between units. The negative pressure generated by the rotation of the device in the natural wind field is used to generate a suction effect on the inside of the garbage mass. At the same time, it combines with the vertical air pipes of adjacent units without unpowered air extraction to form a flow field combining air extraction and suction. The complete air flow path enables external air to pass through the gravel filling layer connected to the air pipe, generating a local air flow turbulence field, and forcing air to diffuse into the garbage mass from three directions: the bottom of the heap and the perforated holes of the ventilation pipe, providing oxygen for the aerobic degradation of the garbage. Description of the Drawings

[0027] Figure 1 is a conceptual diagram of the landfill method with low leachate production disclosed in the present invention.

[0028] Figure 2 is a schematic cross-sectional view of the unpowered air extraction air pipe cluster in the small-unit micro-aerobic landfill storage area.

[0029] Figure 3 is a schematic diagram of the preferred layout of the unpowered air extraction sites in the small-unit micro-aerobic landfill storage area.

[0030] Figure 4 is the landfill gas component detection results of the pilot-scale landfill experiments using the micro-aerobic landfill technology and the traditional anaerobic landfill technology respectively, where: (a) small-unit micro-aerobic landfill; (b) traditional anaerobic landfill.

[0031] Figure 5 The detection results of the leachate water quality indicators in the pilot-scale landfill experiments using the microaerobic landfill technology and the traditional anaerobic landfill technology respectively are as follows: (a) Variation of the leachate water quality indicators in the small-unit microaerobic landfill; (b) Variation of the leachate water quality indicators in the traditional anaerobic landfill.

[0032] Figure 6 The diagrams of the leachate production per unit of waste and the cumulative leachate production in the pilot-scale landfill experiments using the microaerobic landfill technology and the traditional anaerobic landfill technology respectively are as follows: (a) Comparison of the leachate production per unit mass of waste between the small-unit microaerobic landfill and the anaerobic landfill; (b) Comparison of the cumulative leachate production between the small-unit microaerobic landfill and the anaerobic landfill.

[0033] Figure 7 The comparison diagram of the characteristics and settlement data of the residual substances in the operating landfill body of the pilot-scale landfill is as follows: (a) Comparison of the characteristics of the residual substances in the landfill body between the small-unit microaerobic landfill and the anaerobic landfill; (b) Comparison of the settlement properties of the landfill body between the small-unit microaerobic landfill and the anaerobic landfill.

[0034] In all the drawings, the same reference numerals are used to represent the same elements or structures, where: 1 - the outlet pipe equipped with a non-powered air intake device; 2 - the inverted U-shaped intake pipe; 3 - the landfill small unit; 4 - the leachate drainage branch pipe; 5 - the leachate drainage main pipe; 7 - the slope of the landfill area; 8 - the waste landfill body. Detailed implementation manners

[0035] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] Figure 1 It is a conceptual diagram of the landfill method with low leachate production disclosed by the present invention. The landfill method with low leachate production in the present invention is realized based on four aspects: small-unit landfill, low compaction density, surface film covering and non-powered oxygen supply.

[0037] A method for landfilling rural domestic waste with low leachate production and rapid and stable stabilization according to the present invention includes the following content:

[0038] Small-unit landfill: As Figure 2 shown by the dotted-line square in the figure, the size of each unit in the designed landfill area is determined by the aerobic radius of the intake pipe 1 or the outlet pipe 2, and the landfill area is divided into several landfill small units 3. The bottom of the landfill area is a gravel filling layer 6 to achieve the continuity of the landfill operation space for the incoming waste, and the independence and ventilation discreteness between each unit;

[0039] Low compaction density: The landfill process does not require compaction of the incoming garbage, and the garbage is directly filled into the storage area to maintain the original low compaction density of the incoming garbage, and retain sufficient air voids to enhance the later ventilation effect;

[0040] Surface film covering: The surface of the landfill needs to be covered with HDPE film to effectively isolate rainwater from infiltrating and reduce the amount of leachate;

[0041] Unpowered oxygen supply: After the construction of the landfill is completed, no other power is needed to provide oxygen to the landfill. Instead, the unpowered self-induction ventilation process of the landfill is achieved by reasonably arranging the air outlet pipe 1 and the inverted U-shaped air inlet pipe 2 of the unpowered air induction device installed inside the landfill. The distribution diagram of the designed air inlet pipe cluster is as follows: Figure 3 As shown, the low compaction density setting promotes the smooth diffusion of oxygen inside the pile, providing a gas phase basis for aerobic degradation.

[0042] In the present invention, the size of the landfill unit 3 in the landfill process is determined by factors such as garbage composition, moisture content, and reservoir depth, but does not exceed the size of the oxygen influence range of the outlet pipe 1 and the inverted U-shaped air inlet pipe 2 installed with an unpowered induced draft device, wherein the depth of the landfill unit 3 is 2-5m, and the diameter does not exceed 15m. At the same time, the ratio of the diameter of the outlet pipe 1 and the inverted U-shaped air inlet pipe 2 installed with the unpowered induced draft device to the maximum diameter of the landfill unit 3 is ensured to be between 1:150 and 1:50.

[0043] In the present invention, it is not necessary to carry out conventional compaction operation on the incoming garbage. The garbage can be spread and lightly compacted to maintain the bulk density of the garbage at 0.2-0.6t / m 3 Within the scope of; after each landfill operation, the surface of the landfill waste is fixedly covered.

[0044] In the present invention, ventilation during the landfill process is achieved by suction coordination, and the power source is the negative pressure suction generated by the air outlet pipe 1 equipped with an unpowered draft device, which realizes the transmission and retention of oxygen inside the pile body for aerobic degradation of garbage inside the pile body.

[0045] In the present invention, the bottom of the air outlet pipe 1 and the inverted U-shaped air inlet pipe 2 equipped with the unpowered air induction device needs to be pre-buried with a bottom gravel filling layer 6, such as Figure 2 As shown, a complete airflow path combining atmosphere, air duct and gravel filling layer is realized, the residence time of airflow inside the garbage pile is prolonged, and a larger aerobic area is generated by diffusion.

[0046] During the traditional sanitary landfill of garbage, the respiration of microorganisms will rapidly consume the oxygen inside the landfill body in the early stage of garbage landfill, causing the landfill body to enter an anaerobic environment. The degradation of garbage in the anaerobic environment can be roughly divided into the following three stages according to the three-stage theory:

[0047] (1) Acidification stage. Mainly, substances with good solubility such as sugars and proteins are decomposed by microorganisms into various organic acids. The main reaction processes are as follows:

[0048]

[0049] C6H 12 O6 + 2H2 → 2CH3CH2COOH + 2H2O (2)

[0050] (2) Acetification. It is mainly an anaerobic process in which the acidic substances generated in the first stage are converted into acetic acid under the condition of the presence of external electron acceptors. The main reaction processes are as follows:

[0051]

[0052]

[0053] (3) Methanation. It is a process in which microorganisms use anaerobic microorganisms to generate methane from substances such as acids and alcohols containing methyl groups. The main reaction processes are as follows:

[0054] 4H2 + CO2 → CH4 + 2H2O (5)

[0055] CH3COO- + H + → CH4 + CO2 (6)

[0056] 4CH3OH → 3CH4 + CO2 + 2H2O (7)

[0057] The anaerobic decomposition process is very slow, and the quality of the leachate effluent is poor and the yield is high. The problem of secondary pollution is serious, resulting in a relatively high cost of garbage landfill.

[0058] Under the condition of natural draft oxygen supply, there is sufficient oxygen inside the landfill body, which will activate aerobic bacteria to decompose garbage and carry out the aerobic decomposition process of garbage. The main reactions in the aerobic decomposition process are as follows:

[0059] C6H 12 O6 + 6O2 → 6CO2 + 5H2O (8)

[0060] C 46 H 77 O 17 N 12S + 47.25O2 → 12NH3·H2O + 46CO2 + H2S + 7.5H2O (9)

[0061] Under the condition of natural draft oxygen supply, the aerobic degradation process reacts rapidly and generates a large amount of heat, which will cause the temperature inside the landfill body to rise, further accelerating the growth and reproduction of thermophilic bacteria. At the same time, it accelerates the evaporation loss of the moisture inside the landfill body under high-temperature environment, reducing the conversion of moisture into leachate. At the same time, during the draft process, air convection will also carry away the moisture inside the landfill body, realizing the process of leachate reduction.

[0062] Example 1

[0063] The micro-aerobic landfill method for small units of garbage implemented in the present invention mainly includes the following steps:

[0064] The first step: Determine the size of the landfill small unit 3 divided by the pipe diameters of the outlet pipe 1 and the inverted U-shaped inlet pipe 2 equipped with a non-powered draft device and their ventilation influence range. Generally, it is 15m. A secondary blind ditch for leachate drainage is preset at the center position of the bottom of each landfill small unit 3.

[0065] The second step: Lay a DN250 leachate drainage branch pipe 4 in the secondary blind ditch inside each small unit, and equally spaced 40cm leachate diversion holes are drilled on the pipe wall, with the hole diameter ranging from 3cm to 5cm. A gravel filling layer 6 with a thickness of 30cm is laid at the bottom of the unit. Fresh air is supplemented to the gravel filling layer 6 through natural convection and diffusion to achieve the purpose of oxygenation, as Figure 2 shown.

[0066] The third step: Inside the landfill body, the leachate drainage branch pipe 4 is connected to the outlet pipe 1 and the inverted U-shaped inlet pipe 2 equipped with a non-powered draft device. The ratio of their pipe diameters to the size of the landfill small unit does not exceed 1:100. Therefore, DN200 is used as the outlet pipe 1 and the inverted U-shaped inlet pipe 2 equipped with a non-powered draft device. Three-way components are assembled at the connection part between the outlet pipe 1 and the inverted U-shaped inlet pipe 2 equipped with a non-powered draft device and the leachate drainage branch pipe 4. The top of their pipes should be about 1.0m higher than the landfill closure height. At the same time, the outlet pipe 1 of the non-powered draft device installed realizes the air extraction effect from the bottom of the landfill body, and the inverted U-shaped inlet pipe 2 forms the natural inhalation of air, ensuring the gas residence time inside the landfill body, increasing the contact area between fresh air and the landfill body, and realizing the air flow sharing between each landfill small unit 3.

[0067] The fourth step: When carrying out the garbage landfill operation, the incoming garbage does not need to be pretreated such as screening or compaction. Instead, the initial compaction density of the garbage is maintained at 0.4 - 0.5t / m 3That is, the garbage is landfilled layer by layer on the basis of maintaining the original porosity of the garbage itself, fully maintaining the oxygen carried by the garbage pile itself. After each landfill operation is completed, the HDPE film is used to cover the surface of the pile in accordance with the principles of daily covering, medium covering and sealing covering, fully isolating external moisture and ensuring low production of leachate from the garbage pile. When the landfill depth reaches 5m, the landfill operation of this unit is stopped and the next unit is landfilled.

[0068] Step 5: The leachate drainage pipe 5 at the bottom of the landfill area drains a small amount of leachate generated during the landfill process into the leachate regulating tank 6, such as Figure 3 As shown, the discharge can meet the standards after biochemical treatment, and induced draft operation can be achieved under the condition of non-full flow design.

[0069] Example 2

[0070] A village emergency domestic waste landfill has a daily waste intake of 20 tons. It is designed that 1 ton / day of the incoming waste will be treated by a small unit micro-aerobic landfill method for waste test, and a group of traditional anaerobic landfill units will be used for control landfill. The landfill unit 3 is a cylindrical box with a radius of 1.0m and a height of 2.0m. It is built according to the above dimensions. A ruler is pasted on the inner wall of the box to facilitate subsequent measurement of the settlement. A gravel filling layer 6 is set at the bottom of the box to guide the leachate. The thickness is not less than 30cm, and the particle size should be 20mm-60mm. From bottom to top, the particle size gradually decreases. The designed garbage compaction density is 0.6t / m 3 The diameters of the air outlet pipe 1 and the inverted U-shaped air inlet pipe 2 of the unpowered induced draft device are both 100 mm. The leachate drainage pipe 5 is connected to an external valve and passed into the leachate regulating tank 6 for detection and biochemical treatment. Temperature sensors, oxygen content sensors, and pH probes are installed in the small unit pile to realize online monitoring of the pile data.

[0071] After the landfill operation, the above indicators are regularly tested and recorded. Figure 4 As shown in (a) in the figure, 50 days after landfill, the methane content in the vertical ventilation pipe is basically maintained at 0%, H2S drops sharply from the original 60ppm to 0ppm, CO2 gradually decreases from the original 15% to about 2%, and O2 content rises to 15%. The inside of the pile is basically in a micro-aerobic state with aerobic as the main and anaerobic as the auxiliary. At the same time, the leachate is basically no longer produced after about 50 days, or the daily production is very small, less than 0.05L / day, such as Figure 5 As shown in (a) in the figure. One year after landfill, Figure 6 As shown in (a), the amount of leachate produced per unit volume is 0.09m 3 / tLandfill garbage.

[0072] For the small landfill unit using traditional anaerobic landfill, after 100 days of landfill, the methane content in the vertical ventilation pipe decreased from the original 6% to 1%, H2S slowly decreased from the original 200 ppm to 2 ppm, CO2 gradually decreased from the original 22% to about 10%, and the O2 content increased to 6%, as shown in Figure 4 (b) of Figure 5 , which is more in line with the characteristics of traditional anaerobic landfill; at the same time, leachate continued to be generated after 200 days of landfill, as shown in Figure 6 (b) of 3 , and the quality of the leachate remained in a state of high organic matter content. After 1 year of landfill, as shown in Figure 6 (a) of

[0073] , the leachate production was 0.15 m Figure 7 / t of landfill waste. At the same time, as shown in (b) of

[0074] , the moisture in the micro-aerobic landfill unit dissipated relatively quickly, and the leachate stopped being generated when the landfill was less than 50 days old. In the anaerobic landfill unit, the anaerobic reaction inside the pile body was very slow, the biochemical reaction had a long continuous cycle, the leachate continued to be generated and the production was large, and the stabilization process of the garbage pile body was long. It can be seen that the micro-aerobic landfill process has obvious advantages in leachate reduction compared with the traditional anaerobic landfill process.

[0075] In a domestic waste landfill in a certain village and town, the daily incoming waste volume is 15 tons, and it is designed that 3 tons / day of the incoming domestic waste is landfilled by the small-unit micro-aerobic landfill method. The diameter of landfill small unit 3 is 10.0 m, and the waste landfill height is 3.0 m. This height includes a gravel filling layer 6 with a height of 0.4 m laid at the bottom of the landfill unit. After landfill is completed, an HDPE membrane is covered on the top, and the waste compaction density is set at 0.5 t / m 3 . The micro-aerobic landfill unit uses DN100 PVC pipes as the outlet pipe 1 and the inverted U-shaped inlet pipe 2 with a non-powered air induction device. The two are evenly distributed in landfill small unit 3 at a spacing of 2.5 m. The pipe walls are evenly drilled with air guide holes with a pore diameter of 15 mm. The bottom of the pipe is flush with the gravel filling layer 6 at the bottom of the landfill unit, and the top of the pipe extends out of the top film, with the protruding part being 0.4 m high.

[0076] Example 4

[0077] A domestic waste landfill in a certain village and town has a daily incoming waste volume of 30 tons. It is designed that 5 tons / day of the incoming domestic waste is landfilled by the small-unit micro-aerobic landfill method. The diameter of landfill small unit 3 is 20.0 m, and the height of the waste heap is 4.5 m. This height includes a gravel filling layer 6 with a height of 0.35 m laid at the bottom of the landfill unit. After landfill completion, an HDPE membrane is covered on the top. The initial compaction density of the waste is set to 0.3 t / m 3 . For the micro-aerobic landfill small unit 3, a PVC pipe with a diameter of DN200 is used as the air outlet pipe 1 and the inverted U-shaped air inlet pipe 2 for installing the non-powered air induction device. The two are evenly distributed in the landfill small unit 3 at an interval of 4.0 m. Air guide holes with a diameter of 20 mm are drilled at equal distances on the pipe wall. The bottom of the pipe is flush with the gravel filling layer 6 at the bottom of the landfill unit, and the top of the pipe extends out of the top film, with the extended part being 0.4 m high.

[0078] It is easy for those skilled in the art to understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A landfill method for the rapid stabilization of rural domestic waste, characterized in that, Use the oxygen carried by the initial state of the incoming garbage as the initial oxygen demand for subsequent aerobic degradation; arrange a vertical air duct array connecting the bottom leachate drainage pipes at intervals in the landfill storage area. The top of the vertical air duct array is installed with a non-powered air intake device at intervals, and the outlet pipes and inverted U-shaped intake pipes of the non-powered air intake device are arranged alternately; the ventilation method inside the landfill heap is strengthened by the non-powered air intake device, and the power source is the negative pressure suction force generated by the non-powered air intake device, so as to realize the transmission and retention of oxygen inside the heap and be used for the aerobic degradation of the garbage inside the heap; at the same time, the gas density gradient caused by the temperature difference inside and outside the landfill heap is used as the driving force for natural gas convection to assist air intake; the leachate drainage pipe is buried in the gravel filling layer at the bottom of the landfill heap to realize a slow-release air circulation path of atmosphere-air duct-gravel filling layer, so as to extend the residence time of the air flow inside the garbage heap. Use the oxygen influence range of the vertical air duct in the landfill heap as the landfill unit of the vertical air duct. Each vertical air duct is located at the center of its own landfill unit. The ratio of the diameter of the vertical air duct to the diameter of its oxygen influence range is (1:150) to (1:50); the oxygen influence range is the area within the aerobic radius centered on the vertical air duct; realize the continuity of the landfill operation space of the incoming garbage, and the independent ventilation discreteness between each unit. The depth of the landfill unit is 3 - 5 m. The compaction density of the incoming garbage in the initial state is 0.4 - 0.5 t / m 3 ; Cover the surface of the landfill heap with a film to isolate the infiltration of external liquids, thereby reducing leachate. Specifically, the landfill method includes the following steps: (1) Determine the size of the landfill unit divided by the outlet pipe and the inverted U-shaped intake pipe diameter of the non-powered air intake device and its ventilation influence range. A secondary blind ditch for leachate drainage is preset at the center of the bottom of each landfill unit. (2) Lay secondary leachate drainage branch pipes in the secondary blind ditches inside each landfill unit, and drill leachate diversion holes on the pipe walls. Lay a gravel filling layer at the bottom of the unit, and supplement fresh air to the gravel filling layer through natural convection and diffusion to achieve the purpose of oxygenation. (3) Inside the heap, the secondary leachate drainage branch pipes are connected to the outlet pipes and inverted U-shaped intake pipes of the non-powered air intake device. Three-way components are assembled at the connection part between the outlet pipes and inverted U-shaped intake pipes of the non-powered air intake device and the secondary leachate drainage branch pipes. At the same time, the outlet pipes of the non-powered air intake device achieve the air extraction effect from the bottom of the heap, and the inverted U-shaped intake pipes form the natural inhalation of air, ensuring the gas residence time inside the heap, increasing the contact area between fresh air and the garbage heap, and realizing the air flow sharing between each landfill unit. (4)When carrying out landfill operations, the incoming waste does not require screening or compaction pretreatment operations. Instead, it is landfilled layer by layer while maintaining the initial compaction density of the waste at 0.4 - 0.5 t / m 3 , that is, on the basis of maintaining the original porosity of the waste itself, and fully maintaining the oxygen carried by the waste heap body; after each landfill operation is completed, the surface of the heap body is covered in accordance with the principles of daily covering, intermediate covering, and final covering to fully isolate external moisture and ensure a low yield of leachate from the waste heap body; (5) The main leachate drainage pipe at the bottom of the landfill area drains a small amount of leachate generated during the landfill process to the leachate regulation pond for biochemical treatment and then discharges it up to the standard. At the same time, it can also realize the air intake operation under the condition of non-full-flow design.

2. The landfill method according to claim 1, characterized in that, The diameter of the landfill unit does not exceed 15 m.

3. The landfill method according to claim 1, characterized in that, The film used for the film covering is a polyethylene film.

4. The landfill method according to claim 1, characterized in that, The leachate drainage pipe is located in the secondary blind ditch. Through the leachate drainage pipe in the secondary blind ditch, the leachate generated by each landfill unit is collected into the main blind ditch, and then flows into the leachate regulation pool through aggregation for biochemical treatment and is discharged after reaching the standard.

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