CN106077016A - A kind of continuable house refuse quasi-aerobic landfill system and method - Google Patents

Abstract

This application belongs to the technical field of garbage treatment, and specifically relates to a sustainable domestic waste quasi-aerobic landfill system and method, the system includes quasi-aerobic landfill, gas guide and leachate collection pipe network, leachate return device and Old garbage mining and screening device; at least one landfill area is set up in the landfill, and domestic garbage landfill layer units are filled in order in time in the landfill area; old garbage covering layers are arranged on the domestic garbage landfill layer units; The leachate produced by the domestic waste landfill unit with a burial time of less than 2.5 years is recharged to the domestic waste landfill unit with a landfill time of 2 to 2.5 years; The combination of filtrate backflow has the comprehensive effects of accelerating the degradation and aging of domestic waste, realizing the rapid stabilization of the landfill layer, further reducing the amount of methane released, and reducing the emission intensity of leachate pollutants; Capacity and recycling and sustainable use of waste resources.

Description

A sustainable domestic waste quasi-aerobic landfill system and method

technical field

The present application relates to the technical field of garbage disposal, in particular to a sustainable domestic garbage quasi-aerobic landfill system and method.

Background technique

Sanitary landfill disposal of garbage is a final disposal technology developed from traditional stacking and land disposal methods. The specific operating conditions are to lay solid waste into a thin layer of a certain thickness on a site with a good anti-seepage performance liner. Layer, compact and cover with soil. Compared with the traditional simple landfill, sanitary landfill is a safe, economical and effective final disposal method of solid waste, which can greatly reduce the harm of solid waste to the surrounding environment.

In the landfill process, the input is landfill waste and water, and the output is leachate and landfill gas, both of which are the result of the interaction of physical, chemical and biological processes in the landfill. Landfill gas is a kind of mixed gas, its composition includes CH ₄ , CO ₂ , O ₂ , N ₂ , H ₂ and various trace gases, the main components are important greenhouse gases such as CH ₄ and CO ₂ , of which stable CH ₄ content in state landfill gas accounts for about half.

In the current landfill technology, the quasi-aerobic landfill technology connects the end of the leachate collection pipe network of the quasi-aerobic landfill with the atmosphere, and is driven by the temperature difference generated by the fermentation of the landfill to allow the outside atmosphere to pass through the leachate. The collection system and vertical wells enter the garbage layer, thereby making the surface layer of the quasi-aerobic landfill, near the water collection pipe, the area around the vertical well or the exhaust facility aerobic, while the central part of the landfill away from the above-mentioned areas is in an aerobic state. In the anaerobic state, a corresponding facultative aerobic zone is formed between the aerobic and anaerobic zones. Therefore, the microorganisms in the waste landfill of the quasi-aerobic landfill can degrade the organic components in the waste through aerobic decomposition, anaerobic decomposition and facultative aerobic decomposition. The advantages of quasi-aerobic landfill are as follows: 1) Significantly reduce the concentration of organic pollutants in leachate in a short period of time, and the amount of leachate produced is also correspondingly reduced; 2) Compared with traditional anaerobic landfill , quasi-aerobic landfill reduces the amount of greenhouse gas CH ₄ produced by more than half; 3) shortens the stabilization time of landfill waste; 4) construction investment and operation components are relatively low; 5) the technical level of machinery and equipment Low requirements.

Contents of the invention

The purpose of this application is to provide a sustainable domestic waste quasi-aerobic landfill system and method. The system and method combine quasi-aerobic landfill, methane oxidation of landfill cover layer and return flow of leachate, which has many aspects. comprehensive effect.

The concrete technical scheme of this application is:

This application relates to a sustainable domestic waste quasi-aerobic landfill system, including:

A quasi-aerobic landfill, at least one landfill area is set in the quasi-aerobic landfill, and the at least one landfill area is arranged side by side along the width direction of the landfill area, and the landfill area A domestic waste landfill layer is buried, and the domestic waste landfill layer includes at least one domestic waste landfill layer unit that is sequentially buried in time in the length direction of the landfill area; the domestic waste landfill layer unit There is an old garbage covering layer on it; the old garbage covering layer is a mixture of new covering soil and humus soil at a mass ratio of 10:1-2; preferably, the bottom surface of the landfill area is provided with 1-3 The slope of %; Preferably, a separation wall is provided between two adjacent landfill areas;

Gas guiding and leachate collection pipe network, said gas guiding and leachate collecting pipe network includes porous leachate collection main pipes, porous multiple leachate collection branch pipes, and multiple porous leachate collection pipes respectively distributed in each said landfill area Perforated air duct; the leachate collecting main pipe is located on the bottom surface of the landfill area and extends along the length direction of the landfill area, and one end extends out of the quasi-aerobic landfill to communicate with the atmosphere; the perforation The air guide pipe is a vertical pipe, one end communicates with the leachate collecting main pipe, and one end extends to the outside of the domestic waste landfill layer unit to communicate with the atmosphere, and the plurality of perforated air guide pipes are arranged at intervals; the plurality of leachate The collection branch pipes extend along the bottom surface of the landfill area and are arranged at intervals on both sides of the leachate collection main pipe, and communicate with the leachate collection main pipe respectively; two adjacent leachate pipes in the same landfill area The distance between the collection branch pipe and the two adjacent perforated airway tubes is 22-24m, preferably 23m;

A leachate return device, each landfill area is respectively provided with the leachate return device; the leachate return device includes a leachate collection tank, a return pump and a return pipe; the leachate collection tank is located in the leachate collection The main pipe extends out of the port at one end outside the quasi-aerobic landfill; the return pipe includes a liquid inlet port and a liquid outlet port; the liquid inlet port is connected to the leachate collection tank pipeline through the return pump ; The liquid outlet port of the return pipe in the landfill area where the domestic waste landfill layer unit with a landfill time of less than 2.5 years is extended to the domestic waste landfill layer unit with a landfill time of 2 to 2.5 years;

The stale waste excavation and screening device, the stale waste mining and screening device includes stale waste excavation equipment for excavating the stale waste of the domestic waste landfill layer unit with a landfill time of more than 2.5 years and a device for screening the stale waste into plastic waste and humus soil screening equipment; wherein the plastic waste and humus soil are prepared into garbage derived fuel and the old garbage covering layer respectively.

Preferably, the landfill height of the domestic waste landfill layer unit is 5-7m.

Preferably, the compacted density of the domestic waste landfill layer unit is 400-600 kg/m ³ , and the porosity is 41%-60%.

Preferably, the internal diameters of the leachate collection main pipe, the leachate collection branch pipe and the perforated airway are respectively 0.15-0.45m; preferably, the leachate collection main pipe, the leachate collection branch pipe and the The diameters of the holes on the perforated airway were 17-20 mm, and the distance between the holes was 11-15 cm.

Preferably, the leachate collection branch pipe has a length of 50-100 m, and the perforated airway has a length of 7-20 m.

Preferably, the bulk density of the old garbage covering layer is 0.7×10 ³ to 1.0×10 ³ kg/m ³ ; the porosity of the old garbage covering layer is 45% to 60%; the thickness of the old garbage covering layer is It is 50-100cm.

Preferably, the leachate return device further includes a leachate return tank; the return pipe includes a return main pipe and a plurality of return branch pipes that are respectively connected to the return main pipe and arranged at intervals; the return tank passes through the return pump It is connected with the pipeline of the leachate collection tank; the return tank is located above the domestic waste landfill layer unit, and the bottom is provided with a leachate outlet; the return main pipe is provided with a leachate inlet; the leachate outlet is connected to the The leachate inlet is connected; the return branch pipe is provided with a liquid outlet, and the liquid outlet extends into the domestic waste landfill layer unit; the liquid outlet of each return branch pipe is located in the leachate collection main pipe directly above, and close to the two sides of each perforated air duct; preferably, the liquid outlet of the return branch extends into 20-40cm below the surface of the domestic waste landfill layer unit; at the same time, the The horizontal distance between the liquid outlet of the return branch pipe and the nearby perforated airway is 5-7m.

This application relates to a method for sustainable domestic waste quasi-aerobic landfill, using the sustainable domestic waste quasi-aerobic landfill system described above to carry out landfill treatment of domestic waste, specifically including the following steps:

(1) After domestic waste is buried unit by time in the form of domestic waste landfill layer units in the landfill area of the quasi-aerobic landfill, the fermentation of the domestic waste landfill layer units leads to the quasi-aerobic There is a temperature difference between the inside and outside of the landfill, and the external atmosphere diffuses into the interior of the domestic waste landfill layer unit through the leachate collection main pipe, leachate collection branch pipe and perforated air duct that are not full flow under the impetus of the internal and external temperature difference, and make An aerobic state is formed around the leachate collection branch pipe, the leachate collection branch pipe and the perforated airway, an anaerobic zone is formed in an area far away from the aerobic zone, and an anoxic zone is formed between the aerobic zone and the anaerobic zone; The organic matter in the domestic waste landfill layer unit is degraded by the internal microorganisms through aerobic decomposition and anaerobic decomposition;

(2) The landfill gas produced by degradation is partly discharged into the atmosphere through the perforated air duct, and partly passes through the old garbage cover layer, and the methane in the landfill gas is further oxidized by the methane oxidizing bacteria in the old garbage cover layer. Oxidative decomposition; the liquid produced by degradation penetrates downward into the leachate collection main pipe and the leachate collection branch pipe to be collected, and the collected leachate is discharged into the filtrate collection pool along the leachate collection main pipe; and the landfill time The leachate produced by the domestic waste landfill layer units less than 2.5 years old is recharged to the domestic waste landfill layer units with a landfill time of 2 to 2.5 years through the leachate return device, further accelerating the degradation rate of organic matter and Stabilization process of domestic waste landfill layer units;

(3) The obsolete waste in the domestic waste landfill layer unit with a landfill time of more than 2.5 years is excavated to free up landfill space for new domestic waste; the excavated stale waste is screened to separate humus and plastic waste; the humus soil is mixed with new covering soil to form the obsolete garbage covering layer, and the plastic waste is prepared into garbage-derived fuel.

Preferably, the hydraulic load for controlling the return of the leachate is 31-45 L/m ³ ·week.

Preferably, the domestic waste landfill layer unit whose landfill time is 2-2.5 years adopts moisture feedback control in the aerobic zone, and the moisture is controlled at 35-50wt%.

The technical solution provided by the application can achieve the following beneficial effects:

The system and method of the present application combine quasi-aerobic landfill, overburden methane oxidation and leachate reflux, which can accelerate the degradation and aging of domestic waste landfill layer units, realize rapid stabilization of the landfill layer, and further reduce methane release The comprehensive effect of reducing the amount of leachate pollutants and reducing the emission intensity of leachate pollutants; and through the excavation of stale waste, on the one hand, it can free up landfill space for landfill treatment of new domestic waste, thereby realizing the sustainable use of quasi-aerobic landfills. Continuous recycling, on the other hand, after the stale waste is sieved, the sieved humus is recycled to prepare the stale waste covering layer for quasi-aerobic landfill, which can reduce methane gas emissions from quasi-aerobic landfill In addition, the sieved combustible waste plastic materials are prepared into RDF; in this way, the recycling and sustainable utilization of waste resources in quasi-aerobic landfills and quasi-aerobic landfills is realized.

Description of drawings

Fig. 1 is the schematic diagram of gas and liquid flow in the domestic waste landfill layer of the embodiment of the present application;

Fig. 2 is a top view schematic diagram of the layout of the landfill area and the gas guide and leachate collection pipe network of the embodiment of the present application;

Fig. 3 is a three-dimensional schematic diagram of the layout of the gas guiding and leachate collection pipe network in the landfill area of the embodiment of the present application;

Fig. 4 is the gabion sectional structure schematic diagram of the embodiment of the present application;

Fig. 5 is a schematic diagram of the layout position of the leachate backflow device in the domestic waste landfill layer unit of the embodiment of the present application;

reference sign,

1-quasi-aerobic landfill;

11 - bottom surface;

12 - landfill area;

13 - Wall;

2- Domestic waste landfill layer;

21 - Aerobic zone;

22 - anaerobic zone;

3- old garbage overlay;

4- Gas guide and leachate collection pipe network;

41 - leachate collection supervisor;

42 - Leachate collection branch pipe;

43 - perforated airway;

5- Leachate return device;

51 - leachate collection tank;

52 - return supervisor;

53-return branch pipe;

6 - Gabion;

61 - mesh cage;

62 - gravel.

detailed description

In order to make the purpose, technical solution and advantages of the application clearer, the technical solution of the application will be clearly and completely described below in conjunction with the embodiments of the application and the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the application , but not all examples. All other embodiments obtained by those skilled in the art on the basis of the technical solutions and given embodiments provided in this application without creative efforts shall fall within the scope of protection of this application.

The "upper" and "lower" mentioned in the text all refer to the placement state of the structures in the drawings.

This application relates to a sustainable domestic waste quasi-aerobic landfill system, including:

For a quasi-aerobic landfill, at least one landfill area is set in the quasi-aerobic landfill, and at least one landfill area is arranged side by side along the width direction of the landfill area, and domestic waste is buried in each landfill area. The buried layer, the domestic waste landfill layer includes at least one domestic waste landfill layer unit that is sequentially buried in time in the length direction of the landfill area; the domestic waste landfill layer unit is provided with a stale garbage covering layer; The old garbage covering layer is a mixture of new covering soil and humus soil at a mass ratio of 10:1-2;

Air guiding and leachate collection pipe network, the air guiding and leachate collection pipe network includes porous leachate collection main pipes, porous multiple leachate collection branch pipes, and multiple perforated air ducts distributed at the bottom of each landfill area; The leachate collection main pipe is located on the bottom of the landfill area and extends along the length of the landfill area, and one end extends out of the quasi-aerobic landfill to communicate with the atmosphere; the perforated air duct is a vertical pipe, and one end communicates with the leachate collection main pipe 1. One end extends to the outside of the domestic waste landfill layer unit to communicate with the atmosphere, and multiple perforated air ducts are arranged at intervals; multiple leachate collection branch pipes extend along the bottom surface of the landfill area and are arranged at intervals on both sides of the leachate collection main pipe, and They are respectively connected with the leachate collection main pipe; the distance between two adjacent leachate collection branch pipes and two adjacent perforated air ducts in the same landfill area is 22-24m, preferably 23m; as shown in Figure 2 and Figure 3 .

Leachate return device, each landfill area is equipped with a leachate return device; the leachate return device includes a leachate collection tank, a return pump and a return pipe; the leachate collection tank is located in the leachate collection main pipe extending out of the quasi-aerobic landfill The port at the outer end; the return pipe includes a liquid inlet port and a liquid outlet port; the liquid inlet port is connected to the leachate collection tank through a return pump; the landfill unit of the domestic waste landfill layer with a landfill time of less than 2.5 years is located in the landfill area The outlet port of the return pipe extends to the domestic waste landfill unit with a landfill time of 2-2.5 years;

Stale waste mining and screening device, the stale waste mining and screening device includes stale waste excavation equipment for excavating stale waste in the domestic waste landfill layer unit with a landfill time of more than 2.5 years and used to screen stale waste into plastic waste and decayed waste Screening equipment for soil; wherein the plastic waste and humus are prepared into Refuse Derived Fuel (RDF) and the old garbage covering layer respectively.

The present application further relates to a method for sustainable domestic waste quasi-aerobic landfill, using the aforementioned sustainable domestic waste quasi-aerobic landfill system, which specifically includes the following steps:

(1) After domestic waste is buried unit by time in the form of domestic waste landfill layer units in the landfill area of the quasi-aerobic landfill, the fermentation of the domestic waste landfill layer units leads to a temperature difference between the inside and outside of the quasi-aerobic landfill , the external atmosphere diffuses into the interior of the domestic waste landfill layer unit through the leachate collection main pipe, the leachate collection branch pipe and the perforated air duct under the impetus of the internal and external temperature difference, and makes the leachate collection branch pipe, leachate collection branch pipe and An aerobic state is formed around the perforated air duct, an anaerobic zone is formed in the area away from the aerobic zone, and an anoxic zone is formed between the aerobic zone and the anaerobic zone; the organic matter in the domestic waste landfill layer unit is passed by the microorganisms inside Degraded by aerobic decomposition and anaerobic decomposition;

(2) The landfill gas produced by degradation is partially discharged into the atmosphere through the perforated air duct, and partly passes through the old garbage covering layer covering the domestic waste landfill layer unit, and the methane in the landfill gas is absorbed by the old garbage covering layer. The methane-oxidizing bacteria further oxidize and decompose; the liquid generated by the degradation penetrates downward into the leachate collection main pipe and the leachate collection branch pipe to be collected, and the collected leachate is discharged along the leachate collection main pipe into the filtrate collection tank; and the landfill time is 2.5 The leachate produced by the domestic waste landfill layer units less than one year old is further recharged to the domestic waste landfill layer units whose landfill time is 2-2.5 years, further accelerating the degradation of organic matter and the stabilization of the domestic waste landfill layer units process;

(3) The obsolete waste in the domestic waste landfill layer unit with a landfill time of more than 2.5 years is excavated to free up landfill space for new domestic waste; the excavated stale waste is screened to separate humus and Plastic waste: the humus soil is mixed with new covering soil to form the obsolete garbage covering layer, and the plastic waste is prepared into RefuseDerived Fuel (RDF).

Regarding the biodegradation process in the domestic waste landfill layer unit of the quasi-aerobic landfill system, in the aerobic zone, microorganisms use ammonia nitrogen for nitrification reaction; in the anaerobic zone, denitrification is carried out to convert ammonia nitrogen into nitrogen; finally , landfill gas, such as nitrogen, methane and carbon dioxide, is generated inside the domestic waste landfill layer unit, part of the landfill gas directly diffuses from the top of the domestic waste landfill layer into the old garbage covering layer, part of it diffuses into the perforated air duct, and Exhaust to the atmosphere along the perforated airway, as shown in Figure 1.

The sustainable domestic waste quasi-aerobic landfill system and the sustainable domestic waste quasi-aerobic landfill method in this application also specifically include the following improvement features:

As an improvement of the present application, the height of the domestic waste landfill layer unit of the present application is 5-7m. In one landfill area of the quasi-aerobic landfill mentioned above in this application, there may be only one domestic waste landfill layer unit, or there may be more than one domestic waste landfill layer units, which are next to each other along the length direction of the landfill area. Laying; first pile up to form a domestic waste landfill layer unit and set a stale garbage covering layer on the formed domestic waste landfill layer unit, and then pile up next to the previous landfill layer unit along the length of the landfill area The next landfill layer unit until one landfill is filled. After that, the domestic waste is landfilled in the next landfill area. In this way, the landfill time of different domestic waste landfill layer units in the same landfill area is different, and the landfill time of domestic waste landfill layer units in different landfill areas is also different.

As an improvement of the present application, the compacted density of the domestic waste landfill layer unit of the present application is 400-600 kg/m ³ , and the porosity is 41%-60%.

Preferably, on the bottom surface of the landfill area, the leachate collection branch pipe is located at the centerline of the landfill area, and a plurality of leachate collection branch pipes are distributed on both sides of the leachate collection main pipe and arranged at intervals, as shown in FIG. 2 .

As an improvement of the present application, the bottom of the landfill area has a slope of 1-3%, and the leachate collection main pipe and leachate collection branch pipes also have a slope of 1-3%, as shown in FIG. 3 .

The research shows that in the quasi-aerobic landfill, _O2 diffuses in the landfill layer through the leachate collection main pipe, leachate collection branch pipe and perforated air duct, forming an obvious hierarchical effect in the entire landfill layer; quasi-aerobic landfill The concentration of _O2 in the structure takes the vertical perforated air duct as the center, forms an inverted cone shape and diffuses in the landfill, and its influence range is the area surrounded by the quadric surface. Specifically, due to the settlement and compaction of garbage, the upper layer is relatively loose, that is, O ₂ in the upper layer is easier to diffuse downward through the perforated air duct, so the O ₂ concentration in the upper layer is higher, while the O ₂ concentration in the middle and lower layers is only in the perforated air duct. Higher around the trachea, forming an inverted cone-shaped distribution. At the same time, the aerobic radius of the quasi-aerobic landfill is also affected by many factors such as the leachate collection supervisor, the diameter of the perforated air duct, the unit height of the domestic waste landfill layer, and the characteristics of domestic waste.

As an improvement of the present application, in the same landfill area, the distance between two adjacent leachate collection branch pipes and two adjacent vertical perforated air ducts is 22-24m, preferably 23m; after research, it is found that When the distance between the perforated air ducts is about 23m, the ratio of the volume of the aerobic area to the anaerobic area can reach 0.67 in the domestic waste landfill unit. Emissions meet the volume percentage <5% requirement.

As an improvement of the present application, the diameters of the perforations on the leachate collection main pipe, the leachate collection branch pipe and the perforated airway tube are respectively 17-20 mm, and the hole distance is 11-15 cm.

As an improvement of the present application, the inner diameters of the leachate collection main pipe, the perforated airway pipe and the leachate collection branch pipe are 0.15-0.45m. In this application, the inner diameter refers to the inner diameter, and the outer diameter refers to the outer diameter. The size of the pipe diameter can affect the flow velocity of the gas in the leachate collection main pipe and the perforated air duct. Within this range, the air flow velocity in the pipe can be guaranteed not to be affected by the flow friction resistance in the pipe and the inlet resistance of the nozzle.

As an improvement of the present application, the length of the leachate collection branch pipe is 50-100 m; the length of the perforated airway pipe is 7-20 m. It has been found through research that, for a perforated airway, too long a length will lead to a sharp drop in the gas flow rate in the tube. This is because as the length of the pipe increases, the work done by the frictional resistance of the pipe wall becomes larger and larger, so that the flow rate decreases.

Preferably, this application chooses to build a quasi-aerobic landfill in a place with high annual wind speed, which not only helps to increase the flow velocity in the pipe, but also promotes the diffusion of pollutants.

Preferably, the perforated air duct protrudes 30-50 cm from the domestic waste landfill layer unit.

For semi-open quasi-aerobic landfills, the obsolete garbage covering layer of the application has good air permeability, which can ensure that the outside air can infiltrate into the domestic waste landfill layer unit, and at the same time, the methane generated by the domestic waste landfill layer unit is buried. The gas diffuses from the landfill layer to the old garbage cover layer for further oxidation and decomposition. As a material for the covering layer of stale waste, stale waste, that is, mineralized waste, contains a large number of methane oxidizing bacteria in the humus sieved from the stale waste, which not only meets the requirements of the permeability coefficient of the covering material, but also has biological adsorption, removal Smelly effect. The storage capacity of the quasi-aerobic landfill can be greatly regenerated by re-mining the mineralized waste to solve the difficult problem of site selection for the quasi-aerobic landfill, relieve the pressure of the new quasi-aerobic landfill, and realize the quasi-aerobic landfill The capacity space and the recycling and sustainable utilization of waste resources.

In this application, the old garbage covering layer is a mixture of new covering soil and old garbage at a mass ratio of 10:1-2; it can obtain higher methane oxidation efficiency and has better economic feasibility.

Regarding the concept of new covering soil, compared with the old covering soil, in this technical field, the covering soil with less methane oxidizing bacteria content in the new covering soil; the covering soil with higher content of methane oxidizing bacteria in the old covering soil, usually in quasi-aerobic landfill After being covered for 1-2 years, the medium-fresh covering soil is gradually oxidized into old covering soil with methane oxidation capacity due to the environment of methane release. In this process, the growth and proliferation of methanotrophs exist.

As an improvement of the present application, the thickness of the old garbage covering layer is 50-100cm; the bulk density of the old garbage covering layer is 0.7×10 ³ ～1.0×10 ³ kg/m3; the porosity of the old garbage covering layer is 45%～ 60%.

As an implementation of the present application, a separation wall is provided between two adjacent landfill areas.

The leachate collection main pipe, the perforated air duct and the leachate collection branch pipe are buried in the quasi-aerobic landfill and are in direct contact with domestic waste. A gabion is installed outside, and the gabion is composed of crushed stones covering the pipe wall and a mesh cage wrapped with the crushed stones, as shown in Figure 4.

In order to achieve the anti-seepage effect on the bottom surface of the quasi-aerobic landfill, before domestic waste is buried in the quasi-aerobic landfill, an anti-seepage layer is laid on the bottom surface of the quasi-aerobic landfill. The anti-seepage layer includes HDPE film . Further, the anti-seepage layer also includes geotextiles. First lay a layer of HDPE film on the bottom surface of the quasi-aerobic landfill, then lay a layer of geotextile on the HDPE film, and pile up domestic waste on the geotextile. The leachate collection main pipe and the leachate collection branch pipe are also arranged on the anti-seepage layer.

Generally, a layer of clay liner is first laid on the bottom surface of the quasi-aerobic landfill, and then HDPE membrane and geotextile are laid on the clay liner, and then the gas guide and leachate collection pipe network are arranged.

Preferably, a leachate drainage layer is laid on the geotextile; the leachate collection main pipe and the leachate collection branch pipes are embedded in the leachate drainage layer.

In this application, the leachate return device is set up to directly return the leachate produced in the quasi-aerobic landfill to the unit of the domestic waste landfill layer, and use the "biological filter bed" function of the garbage layer to reduce pollutants in the leachate emission intensity. The backflow leachate can supplement the carbon source for the microorganisms to denitrify, which is more conducive to the denitrification. At the same time, leachate recharge in quasi-aerobic landfill can eliminate the accumulation of NH ₄ ⁺ -N concentration caused by traditional anaerobic landfill recharge. In addition, the direct return of leachate has the advantages of saving investment, simple operation, and low operating cost. It can effectively reduce the concentration of pollutants, reduce the amount of leachate produced, accelerate the rate of landfill gas generation and the stabilization process of landfill waste and quasi-aerobic filling. Landfill settlement rate, improve the use efficiency of quasi-aerobic landfill and other advantages; and research shows that after backflow, leachate water quality will not cause water quality deterioration.

As a specific embodiment of the leachate return device of the present application, the leachate return device also includes a leachate return tank; the return pipe includes a return main pipe and a plurality of return branch pipes that are respectively connected to the return main pipe and arranged at intervals; The pump is connected to the leachate collection tank pipeline; the return tank is located above the domestic waste landfill unit, and the bottom is provided with a leachate outlet; the return main pipe is provided with a leachate inlet; the leachate outlet is connected to the leachate inlet; the return branch pipe is provided with The liquid outlet extends to the unit of the domestic waste landfill layer.

As an improvement of this application, in order to make full use of the aerobic-anoxic-anaerobic structure formed by the quasi-aerobic landfill layer, the leachate is returned to the aerobic area, on the one hand to avoid the increase of the aerobic area in the landfill. On the other hand, ensure that the area has good water and nutrient conditions, so that the area can maximize the ability of methane oxidation. That is, the liquid outlet of each return branch pipe is located directly above the leachate collection main pipe, and a return branch pipe is provided on both sides of each perforated air duct; preferably, the liquid outlet of the return branch pipe extends into the domestic waste landfill layer 20-40cm below the surface of the unit; at the same time, the horizontal distance between the liquid outlet of the return branch pipe and the nearby perforated air duct is 5-7m to ensure the return infiltration effect of the leachate, and at the same time ensure that the leachate can pass through the unit of the domestic waste landfill layer in turn aerobic, anoxic and anaerobic zones. As shown in Figure 5, the anoxic region is not marked in the figure.

The above reflux design can effectively adjust the moisture and nutrient content of the garbage in the aerobic area of the quasi-aerobic landfill, so that the aerobic area of the quasi-aerobic landfill can maintain a high methane oxidation efficiency, thereby minimizing methane release of gas.

As an improvement of the present application, the hydraulic load of the leachate backflow should be less than the saturated permeability coefficient of the domestic waste landfill layer unit; preferably, the hydraulic load of the leachate backflow is 31-45L/m ³ ·week. Studies have shown that as the backflow intensity (hydraulic load) increases, the seepage of leachate in the landfill can be significantly accelerated; however, when the hydraulic load is too large, it may be due to the existence of preferential channels inside the garbage heap. There is great inhomogeneity in the moisture content inside the garbage dump.

As an improvement of the present application, the domestic waste landfill unit with a landfill time of 2-2.5 years in the present application adopts moisture feedback control in the aerobic zone, and the moisture content is controlled within the range of less than 35-50wt%.

The following is an exemplary description of the structural parameter settings and effects of the applied quasi-aerobic landfill system through specific examples, as follows:

This example selects a small and medium-sized quasi-aerobic landfill:

In the width direction of the bottom surface of the quasi-aerobic landfill site, multiple landfill areas are arranged side by side, and a separation wall is set between adjacent landfill areas; along the midline position of the bottom surface length direction of each landfill area, both sides are slopes, Slope a=2%, and the bottom surface also has a slope of 2% along the length direction, as shown in Figure 3;

In order to achieve the anti-seepage effect, an anti-seepage layer is laid on the bottom surface of the quasi-aerobic landfill, including laying clay liner, HDPE film, and geotextile in sequence; The filtrate collection pipe network; the main leachate collection pipe (pipe diameter 0.40m, hole diameter 18mm, hole spacing 12cm) is laid along the aforementioned midline position, and the lower end extends from the bottom of the landfill area to the quasi-aerobic landfill; the vertical Straight perforated air ducts (7.5m in length, 0.15m in diameter, 18mm in hole diameter, and 12cm in hole spacing) are connected to the leachate collection main pipe with an interval of 23m between adjacent perforated air ducts; A pair of leachate collection branch pipes (50m in length, 0.15m in diameter, 18mm in hole diameter, and 12cm in hole distance) are respectively arranged on both sides of the connection point between each perforated airway and the leachate collection main pipe; The leachate collection main pipe and leachate collection branch pipe, together with the HDPE membrane and geotextile under the bottom surface, are partially sunk into the clay liner sink;

In order to avoid the clogging of the gas guide and leachate collection pipe network, the leachate collection main pipe and the leachate collection branch pipe are covered with gravel protection, and a layer of leachate drainage layer is laid on the geotextile to collect the leachate. The main pipe and the leachate collection branch are buried in the leachate drainage layer to facilitate the flow of the bottom leachate; the surrounding of the perforated air duct is protected by a gabion;

Then from one end of the landfill area along the length direction, domestic waste is filled to form a landfill layer unit (equal to the landfill area, 7m high, compacted density 400-600kg/m ³ , porosity 41%) ~60), and then pave the obsolete garbage covering layer (a mixture of new covering soil and humus soil at a mass ratio of 10:1.5, with a bulk density of 0.7×10 ³ to 1.0×10 ³ kg/m ³ , on the landfill unit. The porosity is 45% to 60%, and the thickness is 70cm); then, along the length direction of the landfill area, close to the previous landfill layer unit to bury domestic waste to form the next landfill layer unit and lay old For the landfill layer, the parameters are the same as before; it is laid in this way until the entire landfill area is filled to form the domestic waste landfill layer of the landfill area; then the domestic waste is buried in the next landfill area, and the landfill method is the same as before; In this way, due to the different formation times of different domestic waste landfill layer units, the landfill time of domestic waste landfill layer units in each landfill area in a quasi-aerobic landfill is also different;

In this example, the leachate returns, and the leachate flowing out of the leachate collection main pipe is collected in the leachate collection tank, and then returns directly without any treatment; first, the leachate in the leachate collection tank is transported to the high-level backflow through the return pump In the tank, a leachate outlet is set at the bottom of the return tank, and a control valve is set. A horizontal return main pipe is set above the quasi-aerobic landfill. The leachate inlet of the return main pipe is connected with the leachate outlet of the return tank and is lower than The filtrate outlet and the return main pipe are connected with multiple vertical return branch pipes. The liquid outlets of the return branch pipes pass through the old garbage covering layer and lead to 40cm below the surface of the domestic waste landfill layer unit, and the liquid outlets of each return branch pipe are located at the level of the leachate. Directly above the collection main pipe, and near the sides of each perforated airway pipe, set up a return branch pipe at a horizontal interval of 7m, as shown in Figure 5. The hydraulic load of the leachate backflow is controlled at 31-45L/m ³ ·week, and the domestic waste landfill layer unit adopts the water feedback control in the aerobic zone, and the water in the aerobic zone is controlled within the range of 35-50%;

And in this example, the leachate produced by the domestic waste landfill unit with a landfill time of less than 2.5 years is returned to the domestic waste landfill unit with a landfill time of 2 to 2.5 years, which is conducive to accelerating the recovery of organic matter in the landfill layer. biodegradation and accelerate the stabilization process of domestic waste landfill layer units; the stale waste of domestic waste landfill layer units with a landfill time of more than 2.5 years can be excavated to free up landfill space for new landfill Household waste, in this way, the capacity space of the quasi-aerobic landfill can be recycled; experiments have shown that the use of the above-mentioned quasi-aerobic landfill can stabilize the landfill of the domestic waste landfill layer unit in about 2 years, and then return the leachate After 0.5 years, the unit of domestic garbage landfill layer can be completely stabilized; and after the excavation of stale garbage with a landfill time of more than 2.5 years, it will be screened into combustible materials such as plastics, rubber and other waste plastic materials and humus by screening equipment ; combustible plastic waste can be made into garbage-derived fuel and recycled, and humus soil contains a large number of methane-oxidizing bacteria, which can be mixed with new soil to form old garbage cover; thus realizing quasi-aerobic landfill and quasi-aerobic landfill Recycling and sustainable utilization of waste resources in aerobic landfills.

Using the above-mentioned landfill process, the municipal solid waste is subjected to quasi-aerobic landfill treatment; taking a solid waste landfill layer unit in a certain landfill area during the operation process as an example, the domestic waste landfill layer unit reaches After 2 years (24 months), the recharge of leachate is started, and the recharged leachate is produced in the domestic waste landfill unit with a landfill time of less than 2.5 (30 months) years; for leachate and perforated air ducts The landfill gas at the top nozzle was tested for different time periods, and the analysis results are shown in Table 1 and Table 2.

Table 1 The main components of the unit leachate of the domestic waste landfill layer at different landfill times (backflow)

Table 2 The main components of landfill gas in the domestic waste landfill layer unit with different landfill time (return flow)

It can be seen from the above Tables 1 and 2 that: using this method for quasi-aerobic landfill disposal of municipal solid waste, within 1 to 24 months of landfill disposal, the concentrations of COD _Cr and NH ₃ -N in the leachate are significantly decreased to 320.4 and 103.2 mg/L; the concentration of methane in landfill gas increased first and then decreased to 6.44%, and the concentration of oxygen decreased first and then increased to 5.93%. Within 24 to 30 months of landfill disposal, due to the leachate backflow disposal, the stabilization process of landfill waste in the pile is further accelerated. During the backflow process, the concentrations of COD _Cr and NH ₃ -N in the leachate produced by the pile showed a trend of first increasing and then significantly decreasing, and finally decreased to 147.4 and 60.8mg/L; the methane concentration in the landfill gas again showed a first increase The oxygen concentration showed a trend of decreasing first and then increasing, and finally increased to 6.11%. In summary, after 2.5 years of landfill disposal and 0.5 years of leachate return treatment, the quasi-aerobic landfill of domestic waste can achieve better stabilization, and at the same time "quasi-aerobic landfill + leachate return" The process significantly speeds up the stabilization process of landfill domestic waste, and at the same time, the concentration of leachate pollutants produced is low, and the greenhouse gas methane has been effectively reduced, which has significant advantages for the subsequent excavation and utilization of stabilized stale waste.

Taking a municipal solid waste quasi-aerobic landfill unit without leachate backflow as a comparison example, the leachate and the landfill gas at the top nozzle of the perforated air duct were tested for different time periods , the analysis results are shown in Table 3 and Table 4;

Table 3 The main components of the unit leachate in the domestic waste landfill layer with different landfill time (without backflow)

Table 4 Main components of landfill gas in different landfill layers of domestic waste (without backflow)

Comparing Tables 3 and 4 with Tables 1 and 2, it can be seen that after leachate reflux treatment, the concentration of pollutants produced in the landfill pile decreased significantly, the concentration of methane in landfill gas increased first and then decreased, and the concentration of oxygen decreased first. After being lowered, it is raised, and finally the landfill garbage dump has a higher stabilization effect. The landfill without leachate return treatment has a poor stabilization effect (the final leachate pollutant concentration is higher, and the concentration of landfill gas methane is higher), and at the same time, due to the lack of realization of leachate generation for fresh garbage The treatment of this part of the leachate will further lead to higher costs for the subsequent disposal of this part of the leachate.

Although the present application is disclosed as above with preferred embodiments, it is not used to limit the claims. Any person skilled in the art can make some possible changes and modifications without departing from the concept of the present application. Therefore, the present application The scope of protection shall be based on the scope defined by the claims of the present application.

Claims (10)

1. a continuable house refuse quasi-aerobic landfill system, it is characterised in that including:

Quasi-aerobic landfill field, sets at least one landfill district, and at least one landfill edge, district described in described quasi-aerobic landfill field The width in described landfill district is arranged side by side, and in described landfill district, landfill has consumer waste filling and embedding floor, described house refuse to fill out Buried regions is included on the length direction in described landfill district at least one the consumer waste filling and embedding layer unit filled the most successively；Institute State consumer waste filling and embedding layer unit and be provided with old rubbish cover layer；Described old rubbish cover layer is that new earthing is pressed with fertile soil The mixture of mass ratio 10:1～2；Preferably, the bottom surface in described landfill district is provided with the gradient of 1～3% along its length；Adjacent It is provided preferably with divider wall between two described landfill districts；

Inducing QI and leachate collection pipe network, described inducing QI and leachate collection pipe network include being respectively distributed in each described landfill district Porous leachate collection supervisor, many leachate collection arms of porous and many perforation airways；Described percolate Collecting main is positioned on bottom surface, described landfill district and extends along the length direction in described landfill district, and to stretch out described standard aerobic in one end Landfill yard is outer to be communicated with air；Described perforation airway is VERTICAL TUBE, and one end connects with described leachate collection supervisor, one end is prolonged Extend and communicate with air outside described consumer waste filling and embedding layer unit, and the plurality of perforation airway interval is arranged；Described many Leachate collection arm extends and is spaced the both sides being arranged in described leachate collection supervisor along the bottom surface in described landfill district, and point It is not connected with described leachate collection supervisor；Adjacent two described leachate collection arms in same landfill district, adjacent two The spacing distance of described perforation airway is respectively 22～24m, preferably 23m；

Percolate reflux, each landfill district is respectively equipped with described percolate reflux；Described percolate reflux bag Include leachate collection pond, reflux pump and return duct；Described leachate collection pond is positioned at described leachate collection supervisor and stretches out described The port of quasi-aerobic landfill one end outside the venue；Described return duct includes feed liquor port and liquid outlet mouth；Described feed liquor port leads to Cross described reflux pump to be connected with described leachate collection pond pipeline；Landfill time consumer waste filling and embedding layer list below 2.5 years The liquid outlet mouth of the return duct in landfill district, place of unit extends to the landfill time in the consumer waste filling and embedding layer unit of 2～2.5 years；

Old rubbish exploitation screening plant, described old rubbish exploitation screening plant includes for excavating the landfill time in 2.5 years The old rubbish excavating equipment of the above old rubbish of consumer waste filling and embedding layer unit and for old rubbish sieve is divided into plastic cement Waste material and screening plant humous；Wherein said plastic waste materials and fertile soil are prepared to garbage derivatived fuel and institute the most respectively The old rubbish cover layer stated.

House refuse quasi-aerobic landfill system the most according to claim 1, it is characterised in that described consumer waste filling and embedding layer The landfill height of unit is 5～7m.

House refuse quasi-aerobic landfill system the most according to claim 1, it is characterised in that described consumer waste filling and embedding layer The compacted density of unit is 400～600kg/m³, porosity is 41%～60%.

Continuable house refuse quasi-aerobic landfill system the most according to claim 1, it is characterised in that described percolate The internal diameter of collecting main, described leachate collection arm and described perforation airway is respectively 0.15～0.45m；Preferably, institute State the diameter of perforate on leachate collection supervisor, described leachate collection arm and described perforation airway be respectively 17～ 20mm, pitch-row is 11～15cm.

Continuable house refuse quasi-aerobic landfill system the most according to claim 1, it is characterised in that described percolate Collect a length of the 50～100m of arm, a length of the 7～20m of described perforation airway.

Continuable house refuse quasi-aerobic landfill system the most according to claim 1, it is characterised in that described old rubbish The unit weight of rubbish cover layer is 0.7 × 10³～1.0 × 10³kg/m³；The porosity of described old rubbish cover layer be 45%～ 60%；The thickness of described old rubbish cover layer is 50～100cm.

Continuable house refuse quasi-aerobic landfill system the most according to claim 1, it is characterised in that described percolate Reflux also includes percolate return tank；Described return duct includes return main and is connected also with described return main respectively Spaced apart many backflow arms；Described return tank is connected with described leachate collection pond pipeline by described reflux pump；Institute State return tank to be positioned on described consumer waste filling and embedding layer unit, and bottom is provided with percolate outlet；Described return main is provided with Percolate import；The outlet of described percolate is connected with described percolate import；Described backflow arm is provided with liquid outlet, described in go out liquid Mouth extends in described consumer waste filling and embedding layer unit；The liquid outlet of each described backflow arm is positioned at described leachate collection supervisor Surface, and respectively set a described backflow arm near the both sides of each perforation airway；Preferably, the going out of described backflow arm Liquid mouth stretches into below described consumer waste filling and embedding layer unit surface 20～40cm；The liquid outlet of the most described backflow arm is with nearer Perforation airway horizontal interval 5～7m.

8. the method for a continuable house refuse quasi-aerobic landfill, it is characterised in that use claim 1-7 arbitrary described Continuable house refuse quasi-aerobic landfill system carries out the landfill disposal of house refuse, specifically includes following steps:

(1) house refuse in the landfill district of described quasi-aerobic landfill field with the form of consumer waste filling and embedding layer unit temporally by list After unit's landfill, the fermentation of described consumer waste filling and embedding layer unit causes the inside and outside temperature difference that produces in described quasi-aerobic landfill field, and extraneous is big Gas passes through the described leachate collection supervisor of non-flowing full, leachate collection arm and perforation airway under internal-external temperature difference promotes Diffuse into the inside of described consumer waste filling and embedding layer unit, and make described leachate collection arm, leachate collection arm and Perforation airway around formed oxygen condition, away from the formation anaerobic zone, region of aerobic zone, between aerobic zone and anaerobic zone then Form anoxic zone；Organic matter in described consumer waste filling and embedding layer unit is divided by aerobic decomposition and anaerobism by internal microorganism Solution decomposes；

(2) the landfill gas part that degraded produces is emitted in air by described perforation airway, and part is by described old rubbish Rubbish cover layer, the methane in landfill gas is then by the further oxidation Decomposition of methane-oxidizing bacteria in described old rubbish cover layer；Fall Solve the liquid produced to penetrate into downwards described leachate collection supervisor and leachate collection arm and be collected, the diafiltration of collection Liquid is emitted in described filtrate collection pond along described leachate collection supervisor；And fill time house refuse below 2.5 years The percolate that buring layer unit produces then is recharged to the landfill time the life of 2～2.5 years by described percolate reflux Garbage loading embeading layer unit alive, the stabilisation of the degradation rate and consumer waste filling and embedding layer unit that further speed up organic matter is entered Journey；

(3) the old rubbish of landfill time consumer waste filling and embedding layer unit more than 2.5 years vacates landfill space after being mined For filling new house refuse；The old rubbish excavated is sized isolates fertile soil and plastic waste materials；Described fertile soil Being mixed and made into described old rubbish cover layer with new earthing, described plastic waste materials is prepared to garbage derivatived fuel.

The method of continuable house refuse quasi-aerobic landfill the most according to claim 8, it is characterised in that control described The hydraulic load of percolate backflow is 31～45L/m³Week.

The method of continuable house refuse quasi-aerobic landfill the most according to claim 8, it is characterised in that described in fill out Time of burying uses aerobic zone moisture feedback control at the consumer waste filling and embedding layer unit of 2～2.5 years, moisture Control 35～ 50wt%.