Method for reconstructing fly ash landfill based on domestic waste landfill

Abstract

The present application relates to the field of fly ash landfill, and provides a fly ash landfill reconstruction method based on a domestic waste landfill, which comprises the following steps: dividing the domestic waste landfill into a temporary fly ash area and a domestic waste screening and resource utilization area by a partition line, and setting an excavation limit; excavating the garbage in the domestic waste landfill according to the excavation limit, transferring the excavated garbage in the excavation limit to the domestic waste screening and resource utilization area for screening and processing, and constructing an intercept dam at the partition line; after the construction of the intercept dam is completed, fly ash is filled into the temporary fly ash area; when the fly ash is about to form a horizontal thrust on the intercept dam, the fly ash is filled into the other side of the intercept dam; and after the garbage in the domestic waste screening and resource utilization area is excavated and resource utilized, the domestic waste landfill is converted into a fly ash landfill. The garbage in the temporary fly ash area and the domestic waste screening and resource utilization area is excavated and resource utilized, the domestic waste landfill is reconstructed into a fly ash landfill, and the problem that there is no place to dispose of fly ash from a garbage incineration power plant is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fly ash landfill, and particularly relates to a fly ash landfill reconstruction method based on a domestic waste landfill. BACKGROUND

[0002] As the final disposal method of solid waste, landfill plays a role that cannot be replaced by incineration and other resource utilization methods. Domestic waste incineration power plants need to be matched with domestic waste landfills for disposal of fly ash.

[0003] However, when a domestic waste incineration power plant is built, a new domestic waste landfill is often not built, and at the same time, the original domestic waste landfill is in a state close to full capacity and cannot accept fly ash. Even if some landfills still have a remaining capacity, because fly ash zoning landfill is not considered during design, and the operation unit cannot directly mix fly ash with waste, these landfills are only used as emergency landfills and do not accept fly ash. In this way, the final destination of fly ash becomes one of the factors restricting the normal operation of domestic waste incineration power plants. SUMMARY

[0004] The present application provides a fly ash landfill reconstruction method based on a domestic waste landfill, aiming to solve the problem of no place for fly ash of a domestic waste incineration power plant.

[0005] In a first aspect, the present application provides a fly ash landfill reconstruction method based on a domestic waste landfill, comprising:

[0006] The domestic waste landfill is divided into a temporary fly ash area and a domestic waste screening and resource utilization area by a partition line, and an excavation boundary is set; the excavation boundary is pushed out to the domestic waste screening and resource utilization area side according to a preset excavation slope and a preset excavation depth starting from the partition line;

[0007] The garbage in the domestic waste landfill is excavated according to the excavation boundary, and the garbage excavated in the excavation boundary is all transferred to the domestic waste screening and resource utilization area for screening and processing, and an intercepting dam is constructed at the partition line;

[0008] After the construction of the intercepting dam is completed, fly ash is filled into the temporary fly ash area; when the fly ash is about to form a horizontal thrust on the intercepting dam, the fly ash is filled into the other side of the intercepting dam;

[0009] When the garbage in the domestic waste screening and resource utilization area is all excavated and resource utilized, the entire domestic waste landfill is converted into a fly ash landfill.

[0010] In an embodiment, the fly ash landfill reconstruction method based on a domestic waste landfill further comprises:

[0011] In the process of filling fly ash into the temporary fly ash area, the fly ash is bagged and the bagged fly ash is filled into the temporary fly ash area in batches;

[0012] After each batch of bagged fly ash is filled, it is covered by a high-density polyethylene (HDPE) impermeable membrane, and the HDPE impermeable membrane is welded to the bottom HDPE impermeable membrane.

[0013] The intercepting dam is a buttressed retaining wall.

[0014] The fly ash landfill reconstruction method based on the municipal solid waste landfill site further comprises:

[0015] After the construction of the intercepting dam is completed, a new impermeable layer is laid in the first excavation area and the temporary fly ash area, and the original impermeable layer of the municipal solid waste screening and resource utilization area is overlapped with the new impermeable layer; the first excavation area is the overlapping area of the excavation boundary and the municipal solid waste screening and resource utilization area.

[0016] The fly ash landfill reconstruction method based on the municipal solid waste landfill site further comprises:

[0017] After the garbage in the excavation boundary is excavated, if the garbage screening workshop is not completed, the excavated garbage in the excavation boundary is stored on the top of the garbage pile in the municipal solid waste screening and resource utilization area.

[0018] The fly ash landfill reconstruction method based on the municipal solid waste landfill site further comprises:

[0019] According to a predetermined division strategy, the municipal solid waste screening and resource utilization area is divided into the first excavation area and the remaining excavation areas; the remaining excavation areas are the excavation areas in the municipal solid waste screening and resource utilization area except the first excavation area.

[0020] After the garbage in the first excavation area is completely excavated and utilized, fly ash is simultaneously filled into the first excavation area; when the garbage in the remaining excavation areas is completely excavated and utilized, fly ash is preferentially filled into the first excavation area, and after the first excavation area is filled, fly ash is filled into the remaining excavation areas.

[0021] The fly ash landfill reconstruction method based on the municipal solid waste landfill site further comprises:

[0022] When fly ash is filled into the temporary fly ash area, the excavated garbage in the excavation boundary is backfilled into the first excavation area.

[0023] After the garbage in the first excavation area is completely excavated and utilized, fly ash is bagged and filled into the first excavation area in batches.

[0024] The fly ash landfill reconstruction method based on the municipal solid waste landfill site further comprises:

[0025] After the fly ash is buried in the first excavation area, all the waste in the second excavation area is excavated and recycled. Then the fly ash is bagged and buried in the second excavation area in batches.

[0026] After all the waste in the third excavation area is removed and recycled, the fly ash is bagged and landfilled in the third excavation area in batches until all the waste in all excavation areas is removed and recycled, and the fly ash is bagged and landfilled in all excavation areas in batches.

[0027] Methods for renovating fly ash landfills based on municipal solid waste landfills also include:

[0028] During the excavation of the waste in the first excavation area and the remaining excavation areas, the waste screening workshop is a mobile screening workshop.

[0029] Methods for renovating fly ash landfills based on municipal solid waste landfills also include:

[0030] When the waste in the first excavation area and the remaining excavation areas is excavated to the bottom of the site through the mobile screening workshop, an additional layer of HDPE geomembrane is covered on the original impermeable layer of the first excavation area and the remaining excavation areas.

[0031] The present invention provides a method for transforming a municipal solid waste landfill into a fly ash landfill. This method divides the landfill into a temporary fly ash zone and a municipal solid waste screening and resource recovery zone using zoning lines, and sets excavation boundaries. The excavation boundaries are established starting from the zoning lines and extending towards the municipal solid waste screening and resource recovery zone according to a preset excavation slope and depth. Waste in the municipal solid waste landfill is excavated according to the excavation boundaries, and all excavated waste within the boundaries is transferred to the municipal solid waste screening and resource recovery zone for screening and treatment. An interception dam is constructed at the zoning lines. After the interception dam is constructed, fly ash is landfilled in the temporary fly ash zone. When the fly ash is about to exert a lateral thrust on the interception dam, it is landfilled on the other side of the interception dam. Once all waste in the municipal solid waste screening and resource recovery zone has been excavated and recovered, the entire municipal solid waste landfill is transformed into a fly ash landfill.

[0032] In the process of transforming a municipal solid waste landfill into a fly ash landfill, the municipal solid waste landfill is divided into a temporary fly ash area and a municipal solid waste screening and resource recovery area. The fly ash is landfilled in the temporary fly ash area. At the same time, after all the waste in the municipal solid waste screening and resource recovery area is cleared and recovered, the municipal solid waste landfill is transformed into a fly ash landfill. Therefore, the fly ash is landfilled in the municipal solid waste screening and resource recovery area, thus solving the problem of where to dispose of fly ash from waste incineration power plants. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a flowchart illustrating the fly ash landfill transformation method based on municipal solid waste landfills provided by the present invention.

[0035] Figure 2 This is a schematic diagram of the excavation boundary provided by the present invention;

[0036] Figure 3 This is a schematic diagram of waste screening and resource utilization provided by the present invention;

[0037] Figure 4 This is a schematic diagram of the interception dam and seepage prevention system provided by the present invention;

[0038] Figure 5 This is a schematic diagram of the temporary fly ash area fly ash landfill provided by the present invention;

[0039] Figure 6 This is a schematic diagram of the synchronous landfilling of fly ash on both sides of the interception dam provided by the present invention;

[0040] Figure 7 This is a schematic diagram of the seepage prevention system reinforcement provided by the present invention;

[0041] Figure 8 This is a schematic diagram of the completed fly ash landfill conversion provided by the present invention;

[0042] Figure 9 This is a flowchart of the overall scheme of the fly ash landfill transformation method based on municipal solid waste landfill provided by the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0044] This invention provides an embodiment of a method for transforming fly ash landfills based on municipal solid waste landfills. It should be noted that although the logical order is shown in the flowchart, under certain data conditions, the steps shown or described may be completed in a different order than that shown here.

[0045] ReferenceFigure 1 , Figure 1 This is a flowchart illustrating the fly ash landfill modification method based on a municipal solid waste landfill provided by the present invention. The fly ash landfill modification method based on a municipal solid waste landfill provided by this embodiment of the invention includes:

[0046] Step 101: Divide the municipal solid waste landfill into a temporary fly ash zone and a municipal solid waste screening and resource recovery zone using zoning lines, and set excavation boundaries.

[0047] Specifically, suitable municipal solid waste landfills are located around waste-to-energy plants that generate fly ash. After determining the suitable landfills, zoning lines are established. The purpose of these zoning lines is to divide the landfills into different areas. It should be noted that the landfills contain waste piles, and the municipal solid waste in these piles is unsorted and unrecovered.

[0048] In this embodiment, the municipal solid waste landfill is divided into two areas by zoning lines: a temporary fly ash zone and a municipal solid waste screening and resource recovery zone. The temporary fly ash zone is where fly ash from waste incineration is landfilled, while the municipal solid waste screening and resource recovery zone is where municipal solid waste is landfilled and screened for resource recovery. Dividing the municipal solid waste landfill into two areas maximizes its utilization. After determining the zoning lines, excavation boundaries need to be set before subsequent excavation work can begin. It should be noted that the excavation boundaries are linear boundary lines defined for waste excavation work in the municipal solid waste landfill, serving as an effective means of dividing the temporary fly ash zone and the municipal solid waste screening and resource recovery zone and conducting waste excavation.

[0049] Furthermore, the excavation boundary is set by comprehensively considering two main factors: excavation slope and excavation depth. The method for setting the excavation boundary is as follows: starting from the zoning line, the excavation boundary is extended towards the municipal solid waste screening and recycling zone according to the preset excavation slope and preset excavation depth. It should be noted that the excavation slope is determined by the height of the waste pile and the length of the area extended towards the municipal solid waste screening and recycling zone. It can also be understood as the ratio of the height of the waste pile to the length of the area extended towards the municipal solid waste screening and recycling zone. Typically, the ratio of the height of the waste pile to the length of the area extended towards the municipal solid waste screening and recycling zone is 1:2 or 1:3. The excavation depth is usually the depth to the bottom guide layer of the municipal solid waste landfill.

[0050] It should be noted that, in this embodiment, the recommended slope of the municipal solid waste landfill site is at least 2°, determined based on the topography of the landfill site. (Refer to...) Figure 2 , Figure 2This is a schematic diagram of the excavation boundary provided by the present invention. Before excavation, the municipal solid waste landfill has an original impermeable layer and a percolation guiding layer. It should be noted that the original impermeable layer is a structural layer used to prevent leachate from entering the external environment of the municipal solid waste landfill, mainly to prevent leachate migration into the natural environment and to ensure the safety and reliability of the landfill. The percolation guiding layer is a structural layer used to guide leachate into a specific area, directing the leachate to the lowest point of the landfill and concentrating it for discharge from the landfill to a leachate treatment station, mainly to prevent leachate accumulation in the waste pile. Downstream of the impermeable and percolation guiding systems, there is a waste dam to collect and contain the waste, preventing pollution and harm to the surrounding environment.

[0051] Step 102: Excavate the waste in the municipal solid waste landfill according to the excavation boundary, and transfer all the waste excavated within the excavation boundary to the municipal solid waste screening and resource recovery area for screening and treatment, and construct an interception dam at the partition line.

[0052] Specifically, the waste in the municipal solid waste landfill is excavated according to the excavation boundary. In one embodiment, the ratio of the height of the waste pile to the length of the area pushed towards the municipal solid waste screening and resource recovery zone is 1:2. If the height of the waste pile is 10m, then the length of the area pushed towards the municipal solid waste screening and resource recovery zone is 20m. Therefore, the area to be excavated includes the temporary fly ash zone and the waste in the 20m long area pushed towards the municipal solid waste screening and resource recovery zone.

[0053] Furthermore, after all the debris within the excavation boundary is removed, a retaining wall is constructed at the zoning line. It should be noted that in this embodiment, the retaining wall is a buttress retaining wall. It should also be noted that constructing a buttress retaining wall is a common practice in hydraulic engineering. The connecting supports of a buttress retaining wall are typically arranged at fixed intervals on the slope, serving to support the foundation, reduce hydraulic velocity, and evenly distribute lateral and vertical forces, thereby ensuring the stability and safety of the buttress retaining wall.

[0054] Step 103: After the interception dam is constructed, the fly ash is buried in the temporary fly ash area; when the fly ash is about to exert a lateral thrust on the interception dam, the fly ash is buried on the other side of the interception dam.

[0055] Specifically, after the interception dam is constructed, i.e., after the buttress retaining wall is completed, the fly ash is buried in the temporary fly ash area. Further, when the fly ash in the temporary fly ash area accumulates to a certain height, it will exert a lateral thrust on the buttress retaining wall, causing the wall to become unstable. When the fly ash is about to exert a lateral thrust on the interception dam, it is buried on the other side of the interception dam, i.e., the heel side. It should be noted that one side of the buttress retaining wall is the temporary fly ash area, and the heel side of the buttress retaining wall is the municipal solid waste screening and resource recovery area.

[0056] Step 104: After all the waste in the municipal solid waste screening and resource recovery area has been cleared and recovered, the entire municipal solid waste landfill is transformed into a fly ash landfill.

[0057] Specifically, after all the waste in the municipal solid waste screening and recycling zone is excavated and recycled, the fly ash is landfilled in batches in the municipal solid waste screening and recycling zone until all the fly ash is landfilled in the municipal solid waste landfill, and the entire municipal solid waste landfill is transformed into a fly ash landfill.

[0058] The fly ash landfill transformation method based on municipal solid waste landfill provided in this invention divides the municipal solid waste landfill into a temporary fly ash zone and a municipal solid waste screening and resource recovery zone by a zoning line, and sets excavation boundaries. The excavation boundaries are set starting from the zoning line and extending towards the municipal solid waste screening and resource recovery zone according to a preset excavation slope and preset excavation depth. Waste in the municipal solid waste landfill is excavated according to the excavation boundaries, and all the waste excavated within the excavation boundaries is transferred to the municipal solid waste screening and resource recovery zone for screening and treatment. An interception dam is constructed at the zoning line. After the interception dam is constructed, fly ash is landfilled in the temporary fly ash zone. When the fly ash is about to exert a lateral thrust on the interception dam, the fly ash is landfilled on the other side of the interception dam. After all the waste in the municipal solid waste screening and resource recovery zone is excavated and resource-recovered, the entire municipal solid waste landfill is transformed into a fly ash landfill. In the process of transforming a municipal solid waste landfill into a fly ash landfill, the municipal solid waste landfill is divided into a temporary fly ash area and a municipal solid waste screening and resource recovery area. The fly ash is landfilled in the temporary fly ash area. At the same time, after all the waste in the municipal solid waste screening and resource recovery area is cleared and recovered, the municipal solid waste landfill is transformed into a fly ash landfill. Therefore, the fly ash is landfilled in the municipal solid waste screening and resource recovery area, thus solving the problem of where to dispose of fly ash from waste incineration power plants.

[0059] Furthermore, methods for redeveloping fly ash landfills based on municipal solid waste landfills also include:

[0060] After the waste within the excavation boundary is excavated, if the waste screening workshop is not yet completed, the excavated waste within the excavation boundary will be stored on top of the waste pile in the municipal solid waste screening and resource recovery area.

[0061] Specifically, the processing cycle for screening and recycling municipal solid waste in landfills is generally one or several years, and the construction of waste screening workshops also takes time. Therefore, when excavating waste within the excavation boundary, the waste screening workshop may be in an unfinished state.

[0062] Therefore, when excavating waste within the excavation boundary, if the waste screening workshop is not yet completed, the excavated waste will be temporarily stored on top of the waste pile in the municipal solid waste screening section. If the waste screening workshop is completed and operational, some of the excavated waste will be screened and recycled first, and the remaining waste will be stored on top of the waste pile in the municipal solid waste screening section. Subsequently, the waste placed on top of the waste pile will be screened and recycled in batches.

[0063] It should be further noted that in this embodiment, the waste screening workshop is a mobile screening workshop, a skid-mounted structure. The convenience and flexibility of a mobile screening workshop allow it to be placed directly on top of the waste pile for rapid and efficient screening. Through its structure and equipment, the waste screening workshop can screen the waste, separating it into different categories such as combustible lightweight materials, large pieces, and humus. (Refer to...) Figure 3 , Figure 3 This is a schematic diagram of waste screening and resource utilization provided by the present invention.

[0064] Furthermore, methods for redeveloping fly ash landfills based on municipal solid waste landfills also include:

[0065] After the interception dam is constructed, a new anti-seepage layer is laid in the first excavation area and the temporary fly ash area, and the original anti-seepage layer of the municipal solid waste screening and resource recovery area is overlapped with the new anti-seepage layer; the first excavation area is the area where the excavation boundary overlaps with the municipal solid waste screening and resource recovery area.

[0066] Specifically, after the interception dam is constructed, the municipal solid waste screening and resource recovery area will be divided into excavation zones. Specifically, the municipal solid waste screening and resource recovery area will be divided into the first excavation zone and the remaining excavation zones. The first excavation zone is the area where the excavation boundary overlaps with the municipal solid waste screening and resource recovery area. The remaining excavation zones are the excavation zones in the municipal solid waste screening and resource recovery area other than the first excavation zone. The remaining excavation zones include multiple excavation zones from the second excavation zone to the Nth excavation zone.

[0067] During the construction of the interception dam, the original seepage prevention and seepage guidance layers in the area within the excavation boundary will be destroyed. That is, the original seepage prevention and seepage guidance layers in the first excavation area and the temporary fly ash area will be destroyed. Therefore, after the interception dam is completed, a new seepage prevention layer will be laid in the first excavation area and the temporary fly ash area, and the original seepage prevention layer in the municipal solid waste screening and resource recovery area will be overlapped with the new seepage prevention layer.

[0068] In one embodiment, the method for overlapping the original seepage barrier layer and the new seepage barrier layer is a "pressing method". That is, a pre-reserved overlap length is left in the new seepage barrier layer, and then the new seepage barrier layer is placed on the original seepage barrier layer to make it fit tightly against the original seepage barrier layer. Then, it is compacted with professional tools to combine the two seepage barrier materials into one. Therefore, this method can effectively avoid water leakage caused by insufficient overlap.

[0069] Reference Figure 4 , Figure 4 This is a schematic diagram of the interception dam and seepage prevention system provided by the present invention. Since the original seepage prevention layer and seepage guidance layer in the first excavation area and the temporary fly ash area will be destroyed, when setting the zoning line, the temporary fly ash area is set upstream of the seepage prevention layer and seepage guidance layer of the municipal solid waste landfill, so as to protect the downstream seepage prevention system and seepage guidance system.

[0070] Furthermore, methods for redeveloping fly ash landfills based on municipal solid waste landfills also include:

[0071] During the process of burying fly ash into the temporary fly ash area, the fly ash is bagged and then buried into the temporary fly ash area in batches.

[0072] After each batch of bagged fly ash is landfilled, it is covered with a high-density polyethylene (HDPE) geomembrane, and the HDPE geomembrane is welded to the bottom HDPE geomembrane.

[0073] Specifically, during the process of landfilling fly ash into the temporary fly ash area, the fly ash is stored in bags, and the bagged fly ash is landfilled into the temporary fly ash area in batches. In one embodiment, the fly ash is bagged using an automatic packaging machine, which conveys the fly ash to the hopper of the packaging machine, where the machine automatically completes the weighing, metering, and bagging.

[0074] Furthermore, after each batch of bagged fly ash is landfilled, it is covered with an HDPE (High Density Polyethylene) geomembrane, which is then welded to the HDPE geomembrane at the bottom of the site. It should be noted that the HDPE geomembrane is a high-strength, high-density polyethylene geomembrane with excellent impermeability and durability, ensuring that rainwater cannot penetrate below the geomembrane layer during rainy weather.

[0075] Reference Figure 5 , Figure 5This is a schematic diagram of a temporary fly ash landfill area provided by the present invention. The temporary fly ash area does not have a bottom permeate drainage system; therefore, rainwater wells and submersible pumps need to be provided within the storage area to pump out and drain rainwater after rain, preventing rainwater accumulation. It should be noted that the storage area is a temporary fly ash area excavated after waste removal, used for landfilling bagged fly ash.

[0076] Furthermore, methods for redeveloping fly ash landfills based on municipal solid waste landfills also include:

[0077] When the fly ash is buried in the temporary fly ash area, the waste excavated from the excavation boundary is backfilled into the first excavation area;

[0078] After all the waste in the first excavation area is removed and recycled, the fly ash is bagged and landfilled in the first excavation area in batches.

[0079] Specifically, while the fly ash is being landfilled in the temporary fly ash area, some of the excavated waste from the excavation boundary is also being backfilled into the first excavation area. This is done by pressing down on the heel plate of the buttress retaining wall to prevent the fly ash in the temporary fly ash area from accumulating to a certain height and exerting a pushing force on the buttress retaining wall towards the waste screening and recycling area, causing the wall to become unstable and ultimately leading to the collapse of the buttress retaining wall. The remaining waste is still stored on top of the waste pile for drying and screening. It should be noted that the dried waste is relatively dry, making it easier to separate solids and liquids during the screening process, which facilitates the waste screening work to some extent.

[0080] Furthermore, during the excavation of the first excavation area, the lack of backfill material to provide weight and prevent instability of the buttress retaining wall necessitates the simultaneous backfilling of fly ash on both sides of the buttress retaining wall. This ensures weight distribution on both sides, especially the heel side. After all the waste in the first excavation area is removed and recycled, the fly ash is bagged and backfilled in batches into the first excavation area, using the simultaneous backfilling method on both sides of the buttress retaining wall. (Refer to...) Figure 6 , Figure 6 This is a schematic diagram of the synchronous landfilling of fly ash on both sides of the interception dam provided by the present invention.

[0081] Furthermore, methods for redeveloping fly ash landfills based on municipal solid waste landfills also include:

[0082] When the waste in the first excavation area and the remaining excavation areas is excavated to the bottom of the site through the mobile screening workshop, an additional layer of HDPE geomembrane is covered on the original impermeable layer of the first excavation area and the remaining excavation areas.

[0083] Specifically, when excavating the waste in the first and remaining excavation areas through the mobile screening workshop down to the site floor, a high-density polyethylene (HDPE) geomembrane is then laid over the original impermeable layer in these areas. Protected by the HDPE geomembrane, rainwater will not seep into the site floor during rainy days, ensuring separation of rainwater and wastewater, preventing rainwater from entering the waste and forming leachate, which would then enter the site floor drainage system. (Refer to...) Figure 7 , Figure 7 This is a schematic diagram of the seepage prevention system reinforcement provided by the present invention.

[0084] Furthermore, methods for redeveloping fly ash landfills based on municipal solid waste landfills also include:

[0085] After the fly ash is buried in the first excavation area, all the waste in the second excavation area is excavated and recycled. Then the fly ash is bagged and buried in the second excavation area in batches.

[0086] After all the waste in the third excavation area is removed and recycled, the fly ash is bagged and landfilled in the third excavation area in batches until all the waste in all excavation areas is removed and recycled, and the fly ash is bagged and landfilled in all excavation areas in batches.

[0087] Specifically, according to a preset division strategy, the municipal solid waste screening and resource recovery area is divided into a first excavation area and other excavation areas. The first excavation area is the area where the excavation boundary overlaps with the municipal solid waste screening and resource recovery area. The other excavation areas are the excavation areas in the municipal solid waste screening and resource recovery area other than the first excavation area. The other excavation areas include multiple excavation areas from the second excavation area to the Nth excavation area.

[0088] After the fly ash is landfilled in the first excavation area, the waste in the second excavation area is excavated and screened. After all the waste in the second excavation area is removed and recycled, the fly ash is bagged, processed, and landfilled in the second excavation area in batches. After each batch of bagged fly ash is landfilled, the bagged fly ash is covered with a high-density polyethylene (HDPE) geomembrane, and the HDPE geomembrane covering the fly ash bags is welded to the HDPE geomembrane at the bottom of the site.

[0089] Furthermore, after all the waste in the third excavation area is cleared and recycled, the fly ash is bagged and landfilled in the third excavation area in batches until all the waste in all excavation areas is cleared and recycled, and the fly ash is bagged and landfilled in all excavation areas in batches. The HDPE geomembrane is then used to cover the fly ash bags and to weld the bottom HDPE geomembrane.

[0090] Furthermore, in the process of transforming fly ash landfills based on municipal solid waste landfills, after all municipal solid waste in the waste screening and resource recovery zone has been excavated and screened, the combustible materials after screening are transported to the waste-to-energy incineration plant. This ensures a sufficient supply of combustible materials for the waste-to-energy incineration plant, thereby guaranteeing the scale of incineration and enabling the plant to generate a continuous and stable amount of electricity. This, in turn, ensures the profitability of the waste-to-energy incineration plant, maximizes the utilization of municipal solid waste resources, and solves the problem of the previous operating losses of waste-to-energy incineration plants.

[0091] Furthermore, all municipal solid waste in the waste sorting and resource recovery zone has been excavated and sorted, preventing it from occupying the landfill for extended periods. This allows the landfill to be successfully used as a fly ash landfill, achieving a method for gradually transforming the municipal solid waste landfill into a fly ash landfill and solving the problem of where to dispose of fly ash from waste-to-energy plants. (Reference) Figure 8 , Figure 8 This is a schematic diagram illustrating the completion of fly ash landfill conversion provided by the present invention.

[0092] Furthermore, referring to Figure 9 , Figure 9 This is a flowchart illustrating the overall scheme of the fly ash landfill transformation method based on municipal solid waste landfills provided by the present invention. The overall process of the fly ash landfill transformation method based on municipal solid waste landfills provided by the embodiments of the present invention can be understood as follows:

[0093] After locating suitable municipal solid waste landfills around waste-to-energy plants that generate fly ash, the zoning lines of the municipal solid waste landfills are determined, and the landfill area is divided into a temporary fly ash zone and a municipal solid waste screening and resource recovery zone according to the zoning lines.

[0094] Starting from the zoning line, the excavation boundary is pushed out towards the municipal solid waste screening and resource recovery zone according to the preset excavation slope and preset excavation depth. At the same time, the municipal solid waste screening and resource recovery zone is divided into the first excavation zone, the second excavation zone to the Nth excavation zone according to the preset division strategy.

[0095] Furthermore, according to the excavation boundary, the garbage within the excavation boundary is excavated first, that is, the garbage in the two areas of temporary fly ash zone and first excavation zone is excavated first. After all the garbage within the excavation boundary is cleared, an interception dam is constructed at the zoning line, that is, a buttress retaining wall is constructed.

[0096] Furthermore, during the construction of the interception dam, the original impermeable and permeable layers within the excavation boundary will be destroyed. That is, the original impermeable and permeable layers in the first excavation area and the temporary fly ash area will be destroyed. Therefore, after the interception dam is completed, a new impermeable layer will be laid in the first excavation area and the temporary fly ash area, and the original impermeable layer in the municipal solid waste screening and resource recovery area will be overlapped with the new impermeable layer. Simultaneously with the completion of the interception dam, the mobile screening workshop has also been completed and is ready for the screening and resource recovery of excavated waste.

[0097] After the interception dam was constructed, the fly ash was stored in bags and then landfilled in batches into a temporary fly ash area. After each batch of bagged fly ash was landfilled, it was covered with a high-density polyethylene (HDPE) geomembrane, which was then welded to the HDPE geomembrane at the bottom of the site.

[0098] While the fly ash was being landfilled in the temporary fly ash area, some of the excavated waste from the excavation boundary was also backfilled into the first excavation area. The remaining waste was stored on top of the waste pile for drying and resource recovery screening. During the excavation of the first excavation area, the lack of backfill waste to provide weight and prevent the instability of the buttress retaining wall meant that after all the waste in the first excavation area was cleared and recovered, the fly ash was bagged and landfilled in the first excavation area in batches, using a method of simultaneous landfilling of fly ash on both sides of the buttress retaining wall.

[0099] After the fly ash is landfilled in the first excavation area, the waste in the second excavation area is excavated and screened. After all the waste in the second excavation area is removed and recycled, the fly ash is bagged, treated, and landfilled in the second excavation area in batches. After each batch of bagged fly ash is landfilled, the fly ash bags are covered with a high-density polyethylene (HDPE) geomembrane, and the HDPE geomembrane covering the fly ash bags is welded to the HDPE geomembrane at the bottom of the site. After all the waste in the third excavation area is removed and recycled, the fly ash is bagged and landfilled in the third excavation area in batches until all the waste in all excavation areas is removed and recycled, and the fly ash is bagged and landfilled in all excavation areas in batches, completing the HDPE geomembrane covering of the fly ash bags and the welding of the bottom HDPE geomembrane. Ultimately, all the waste in the municipal solid waste landfill was excavated and recycled, and the fly ash was bagged and disposed of in the municipal solid waste landfill. The excavated and screened recycled waste was sent to a waste-to-energy plant for incineration. Thus, the transformation of the municipal solid waste landfill into a fly ash landfill was successfully completed.

[0100] In the process of transforming municipal solid waste landfills into fly ash landfills, the landfills are divided into temporary fly ash zones and municipal solid waste screening and resource recovery zones. Fly ash is initially placed in the temporary fly ash zone. Simultaneously, after all waste in the screening and resource recovery zone is removed and recovered, the municipal solid waste landfill is transformed into a fly ash landfill. Therefore, placing fly ash in the screening and resource recovery zone solves the problem of where to dispose of fly ash from waste-to-energy plants. Furthermore, the combustible materials from the resource recovery of municipal solid waste in the landfill are transported to the waste-to-energy plant, ensuring a sufficient supply of combustible materials. This guarantees the incineration capacity of the waste-to-energy plant, resulting in a continuous and stable power generation, ensuring the plant's profitability, maximizing the utilization of municipal solid waste resources, and resolving the previous issue of waste-to-energy plants operating at a loss.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for the transformation of fly ash landfills from municipal solid waste landfills, characterized in that, include: The municipal solid waste landfill is divided into a temporary fly ash zone and a municipal solid waste screening and resource recovery zone by zoning lines, and excavation boundaries are set. The excavation boundary is defined as starting from the zoning line and extending towards the municipal solid waste screening and resource recovery zone according to a preset excavation slope and a preset excavation depth; the preset excavation slope is the ratio of the height of the waste cone to the length of the area extended towards the municipal solid waste screening and resource recovery zone. The preset excavation depth is the depth to which the diversion layer at the bottom of the municipal solid waste landfill is excavated; Excavate the waste in the municipal solid waste landfill according to the excavation boundary, and transfer all the waste excavated within the excavation boundary to the municipal solid waste screening and resource recovery area for screening and treatment, and construct an interception dam at the zoning line; After the interception dam is constructed, the fly ash will be buried in the temporary fly ash area; while burying the fly ash in the temporary fly ash area, the waste excavated from the excavation boundary will be backfilled into the first excavation area; when the fly ash is about to exert a lateral thrust on the interception dam, the fly ash will be buried on the other side of the interception dam; wherein, the first excavation area is the overlapping area between the excavation boundary and the municipal solid waste screening and resource utilization area; Once all the waste in the municipal solid waste screening and recycling zone has been cleared and recycled, the entire municipal solid waste landfill will be transformed into a fly ash landfill.

2. The method for transforming fly ash landfills based on municipal solid waste landfills according to claim 1, characterized in that, Also includes: During the process of burying fly ash into the temporary fly ash area, the fly ash is bagged and then buried into the temporary fly ash area in batches. After each batch of bagged fly ash is landfilled, it is covered with a high-density polyethylene (HDPE) geomembrane, and the HDPE geomembrane is welded to the bottom HDPE geomembrane.

3. The method for transforming fly ash landfills based on municipal solid waste landfills according to claim 1 or 2, characterized in that, The interception dam is a buttress-type retaining wall.

4. The method for transforming fly ash landfills based on municipal solid waste landfills according to claim 1, characterized in that, Also includes: After the interception dam is constructed, a new anti-seepage layer is laid in the first excavation area and the temporary fly ash area, and the original anti-seepage layer in the municipal solid waste screening and resource recovery area is overlapped with the new anti-seepage layer.

5. The method for transforming fly ash landfills based on municipal solid waste landfills according to claim 4, characterized in that, Also includes: After the waste within the excavation boundary is excavated, if the waste screening workshop is not yet completed, the excavated waste within the excavation boundary will be stored on top of the waste pile in the municipal solid waste screening and resource recovery area.

6. The method for transforming fly ash landfills based on municipal solid waste landfills according to claim 5, characterized in that, Also includes: According to a preset division strategy, the municipal solid waste screening and resource recovery area is divided into the first excavation area and the remaining excavation areas; The remaining excavation areas are: the excavation areas other than the first excavation area in the municipal solid waste screening and resource recovery area; After all the waste in the first excavation area is cleared and recycled, the fly ash is simultaneously landfilled in the first excavation area; when all the waste in the other excavation areas is cleared and recycled, the fly ash is first landfilled in the first excavation area, and after the first excavation area is filled, it is then filled into the other excavation areas.

7. The method for transforming fly ash landfills based on municipal solid waste landfills according to claim 6, characterized in that, Also includes: After all the waste in the first excavation area is removed and recycled, the fly ash is bagged and landfilled in the first excavation area in batches.

8. The method for transforming fly ash landfills based on municipal solid waste landfills according to claim 7, characterized in that, Also includes: After the fly ash is buried in the first excavation area, all the waste in the second excavation area is excavated and recycled. Then the fly ash is bagged and buried in the second excavation area in batches. After all the waste in the third excavation area is removed and recycled, the fly ash is bagged and landfilled in the third excavation area in batches until all the waste in all excavation areas is removed and recycled, and the fly ash is bagged and landfilled in all excavation areas in batches.

9. The method for transforming fly ash landfills based on municipal solid waste landfills according to claim 8, characterized in that, Also includes: During the excavation of the waste in the first excavation area and the remaining excavation areas, the waste screening workshop is a mobile screening workshop.

10. The method for transforming fly ash landfills based on municipal solid waste landfills according to claim 9, characterized in that, Also includes: When the waste in the first excavation area and the remaining excavation areas is excavated to the bottom of the site through the mobile screening workshop, an additional layer of HDPE geomembrane is covered on the original impermeable layer of the first excavation area and the remaining excavation areas.

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