A combined screening method for stockpiled waste in a landfill

Abstract

The present invention relates to a combined screening method for stock waste in a landfill, and belongs to the technical field of stock waste screening. The present invention adopts a pre-sorting combined with fine screening method to perform multiple sorting and screening treatments on the stock waste in the landfill, divides the process route into pre-sorting mechanical treatment, biological drying treatment, and fine screening mechanical treatment, and constructs different functional areas at the same time. The pre-sorting is used as a reliable pretreatment technology at the front end, and the fine screening is used to consolidate and improve the technology at the back end, forming a set of combined screening methods that complement each other. The sorting specifications and destination of the stock waste are further refined from the overall perspective, greatly improving the effective utilization rate of the stock waste, promoting the sustainable development of the urban economy to a certain extent, and making significant contributions to improving people's quality of life and building an ecological environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of stock waste screening, and in particular relates to a combined screening method for stock waste in a landfill. Background Art

[0002] As a receiving site for municipal solid waste, landfills effectively address the problem of municipal solid waste disposal and contribute significantly to the rapid development of cities. However, with the acceleration of urban development and population growth, urban areas have gradually expanded. Consequently, many landfills located in suburban areas have been relocated to the suburbs or even the city center. The presence of landfills not only causes greater pollution to the surrounding environment but also poses serious problems for the production and daily lives of surrounding residents. Furthermore, the existence of landfills significantly reduces the value of the original sites, forcing many landfills to face relocation challenges. Some landfills that have been out of use for many years are difficult to relocate due to their age and require screening and disposal.

[0003] However, current methods for managing waste stockpiles have problems such as complex processes, high equipment investment, large land area requirements, and low post-screening utilization rates. They cannot quickly and effectively separate heavy aggregates, lightweight materials, humus, and metals from the waste stockpiles. Furthermore, the waste stockpiles become inhomogeneous during screening and crushing. Furthermore, since the screened lightweight materials are not packaged, they are scattered in the open air, impacting the surrounding environment. Therefore, it is particularly necessary to provide a combined screening method for waste stockpiles in landfills with high utilization rates. Summary of the Invention

[0004] The present invention aims to provide a combined screening method for stock waste in landfills. The present invention uses a pre-sorting combined with fine screening method to perform multiple sorting and screening treatments on the stock waste in the landfill. The process route is divided into pre-sorting mechanical treatment, biological drying treatment, and fine screening mechanical treatment. Different functional areas are simultaneously constructed. The pre-sorting is used as a reliable pretreatment technology at the front end, and the fine screening is used to consolidate and improve the technology at the back end, forming a set of complementary combined screening methods. The sorting specifications and destination of the stock waste are further refined from the overall perspective, greatly improving the effective utilization rate of the stock waste, promoting the sustainable development of the urban economy to a certain extent, and making significant contributions to improving people's quality of life and building an ecological environment. The present invention solves the problem of low effective utilization rate of stock waste screening methods in the existing technology.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A combined screening method for stock waste in a landfill comprises the following steps:

[0007] (1) Pre-sorting: The stock garbage in the landfill is loaded into the feeder by a forklift and transported to the sorting platform to obtain sorted material, which is then sent to the first combined drum screen for pre-sorting to obtain the first oversize, the first midsize, and the first undersize;

[0008] (2) Air separation and crushing: The first sieve material and the first sieve material are air-separated respectively, and then moved to a crusher and crushed by adjusting the hot air temperature to obtain a first homogeneous material and a second homogeneous material respectively;

[0009] (3) biological drying: biologically drying the first undersize material, the first homogenized material, and the second homogenized material to obtain a dried material;

[0010] (4) Fine screening: The dried material is sent to the second combined drum screen for screening, followed by air separation, magnetic separation and packaging to obtain the second undersize material, metal materials, bone materials and fine screening packaging materials;

[0011] (5) Resource utilization: The second screened material, metal materials, bone materials and finely screened packaged materials are recycled.

[0012] As a preferred embodiment of the present invention, in step (1), the first combined drum screen is a first combined drum screen with a pore size of 180-190 mm and a pore size of 90-100 mm combined together, thereby forming a gradient combined screening;

[0013] The gradient combined screening has the advantages of more compact sorting process, high degree of integration and smaller footprint.

[0014] As a preferred embodiment of the present invention, step (2) is specifically as follows: the first screen material and the first screen material are subjected to the first air separation and the second air separation respectively to obtain the first air separation heavy material, the first air separation light material and the second air separation heavy material, the second air separation light material; the first air separation heavy material, the second air separation heavy material and the first air separation light material, the second air separation light material are mixed and moved to a crusher; at the same time, the hot air blower is turned on and the hot air temperature is adjusted for crushing to obtain the first homogeneous material and the second homogeneous material respectively.

[0015] As a preferred embodiment of the present invention, the hot air temperature in step (2) is 50-55°C;

[0016] Turn on the hot air blower and adjust the temperature to 50-55℃. Use forced hot air to dry the garbage, which is beneficial for garbage separation and easier for subsequent processing.

[0017] As a preferred embodiment of the present invention, step (3) is specifically as follows: randomly turning over and mixing the first undersize material, the first homogeneous material and the second homogeneous material to form a conical pile, covering the conical pile with a layer of transparent film, heating, exhausting, ventilating and stirring the conical pile until drying is completed to obtain a dried processed material.

[0018] As a preferred solution of the present invention, the height of the conical stacking material is 2-2.4m, and the slope is 50-60°.

[0019] As a preferred solution of the present invention, the bottom end of the transparent film has a clearance height of 0.2-0.3 m, and the top end has a clearance height of 0.4-0.6 m.

[0020] As a preferred embodiment of the present invention, step (4) is specifically as follows: the dried material is sent to the second combined drum screen for screening to obtain the second oversize material, the second midsize material and the second undersize material, the second oversize material and the second midsize material are subjected to the third air separation and the fourth air separation respectively to obtain the third air separation heavy material, the third air separation light material and the fourth air separation heavy material, the third air separation heavy material and the fourth air separation light material, the third air separation heavy material and the fourth air separation heavy material are subjected to magnetic separation and separation by a magnetic separator to obtain metal materials and bone materials, the third air separation light material and the fourth air separation light material are mixed and packaged by a baler to obtain finely screened packaged material.

[0021] As a preferred solution of the present invention, in step (4), the second combined drum screen is a drum screen with an aperture of 20-30 mm and a drum screen with an aperture of 60 mm combined together to form a gradient combined screening.

[0022] As a preferred embodiment of the present invention, step (5) is specifically as follows: using the second screen undersize material to prepare humus soil material for plant cultivation, backfilling, covering landfill required soil resources and non-food chain landscaping soil resource comprehensive utilization; separating the metal materials through classification recovery, recycling and reuse as reusable materials by the material company; grinding and crushing the bone materials into bone powder, bone ash and other materials for feed, fertilizer, or direct backfilling or as raw materials for environmentally friendly building materials; making the finely screened packaged materials into RDF as an environmentally friendly alternative fuel for heat source users such as cement plants, waste incineration power plants and coal-fired power plants.

[0023] Beneficial effects of the present invention:

[0024] (1) The present invention adopts a method of pre-sorting combined with fine screening to carry out multiple sorting and screening treatments on the stock garbage in the landfill, and divides the process route into pre-sorting mechanical treatment, biological drying treatment and fine screening mechanical treatment. At the same time, different functional areas are constructed, and the early pre-sorting is used as a reliable pretreatment technology at the front end and the fine screening is used to consolidate and improve the technology at the back end to form a set of combined screening methods that complement each other. The sorting specifications and destinations of the stock garbage are further refined from the overall perspective, so that the effective utilization rate of the stock garbage can reach 95%, which greatly improves the utilization rate of the combined screening method for stock garbage, promotes the sustainable development of the urban economy to a certain extent, and makes significant contributions to improving people's quality of life and building an ecological environment.

[0025] (2) The present invention adopts a combination of drum screens with different apertures to form a gradient combined screening during pre-sorting and fine screening. The formed gradient combined screening can screen multiple stocks of garbage of different sizes at one time, and has the advantages of a more compact sorting process, a high degree of integration, and a smaller footprint. At the same time, the hot air blower is turned on in the crushing link and the temperature is adjusted to 50-55°C. The garbage is dried by forced hot air, which is beneficial to assist in the separation of the garbage, making the garbage more homogenized and convenient for subsequent processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 The present invention is a schematic flow chart of a combined screening method for stock garbage in a landfill. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] like Figure 1 The figure shows a flow chart of a combined screening method for stock garbage in a landfill according to the present invention.

[0030] Example 1

[0031] A combined screening method for stock waste in a landfill comprises the following steps:

[0032] (1) Pre-sorting: The stock garbage in the landfill is loaded into the feeder by a forklift and transported to the sorting platform to obtain sorted material, which is then sent to the first combined drum screen with an aperture of 180 mm and a drum screen of 95 mm for pre-sorting, thereby forming a gradient combined screening and obtaining the first oversize, the first midsize, and the first undersize;

[0033] (2) air separation and crushing: the first sieve oversize and the first sieve medium are subjected to the first air separation and the second air separation, respectively, to obtain the first air separation heavy material, the first air separation light material, the second air separation heavy material, and the second air separation light material; the first air separation heavy material, the second air separation heavy material, and the first air separation light material, and the second air separation light material are mixed and transferred to a crusher; at the same time, a hot air blower is turned on and the hot air temperature is adjusted to 55°C for crushing, to obtain the first homogeneous material and the second homogeneous material, respectively;

[0034] (3) Biological drying: The first undersize material, the first homogenized material, and the second homogenized material are randomly turned over and mixed to form a conical pile with a height of 2 m and a slope of 55°. A transparent film with a bottom clearance of 0.2 m and a top clearance of 0.4 m is covered on the conical pile. The conical pile is heated, evacuated, ventilated, and stirred until drying is completed to obtain a dried material.

[0035] (4) Fine screening: The dried material is fed into a second combined drum screen with an aperture of 20 mm and a 60 mm, and subjected to gradient combined screening to obtain a second oversize material, a second midsize material, and a second undersize material. The second oversize material and the second midsize material are subjected to a third air separation and a fourth air separation, respectively, to obtain a third air separation heavy material, a third air separation light material, and a fourth air separation heavy material and a fourth air separation light material. The third air separation heavy material and the fourth air separation heavy material are subjected to magnetic separation by a magnetic separator and separated to obtain metal materials and bone materials. The third air separation light material and the fourth air separation light material are mixed and packaged by a baler to obtain finely screened packaged material.

[0036] (5) Resource utilization: The second screened material is used to prepare humus materials, which are used for plant cultivation, backfilling, covering landfills, and comprehensive utilization of non-food chain landscaping soil resources; the separated metal materials are recycled and reused as reusable materials by the material company through classification; the bone materials are ground and crushed to make bone powder, bone ash and other materials for feed and fertilizer, or directly backfilled or used as raw materials for environmentally friendly building materials; the finely screened baled materials are made into RDF as an environmentally friendly alternative fuel for heat source users such as cement plants, waste incineration power plants and coal-fired power plants.

[0037] Example 2

[0038] Compared with Example 1, the differences are that the first combined drum screen in step (1) is a first combined drum screen with an aperture of 185 mm and a drum screen with an aperture of 90 mm; the hot air temperature in step (2) is 53°C; and the second combined drum in step (3) is a second combined drum screen with an aperture of 30 mm and a drum screen with an aperture of 60 mm. The remaining parameters and operating steps remain unchanged.

[0039] Example 3

[0040] Compared with Example 1, the differences are that the first combined drum screen in step (1) is a first combined drum screen with a pore size of 190 mm and a pore size of 100 mm combined together; the hot air temperature in step (2) is 50°C; and the second combined drum in step (3) is a second combined drum screen with a pore size of 25 mm and a pore size of 60 mm combined together. The other parameters and operating steps remain unchanged.

[0041] Comparative Example 1

[0042] Compared with Example 1, the difference is that the pre-sorting in step (1) is not performed, that is, the stock garbage in the landfill is directly sorted and crushed from step (2), specifically:

[0043] (1) Air separation and crushing: The waste in the landfill is air-separated to obtain a first air-separated heavy material and a first air-separated light material. The first air-separated heavy material and the second air-separated light material are mixed and moved to a crusher. At the same time, a hot air blower is turned on and the hot air temperature is adjusted to 55°C for crushing to obtain a first homogeneous material and a second homogeneous material respectively.

[0044] (2) Bio-drying: Compared with step (3) of Example 1, the first undersize was omitted, and the remaining parameters and operating steps remained unchanged;

[0045] (3) Fine screening: the same as step (4) of Example 1.

[0046] Comparative Example 2

[0047] Compared with Example 1, the difference is that step (2) of air separation and crushing is not performed, specifically:

[0048] (1) Pre-sorting: the same as step (4) of Example 1;

[0049] (2) Biological drying: The first sieve oversize, the first sieve middle and the first sieve undersize are randomly turned over and mixed to form a conical pile with a height of 2m and a slope of 55°. A transparent film with a bottom clearance of 0.2m and a top clearance of 0.4m is covered on the conical pile. The conical pile is heated, evacuated, ventilated and stirred until drying is completed to obtain a dried material.

[0050] (3) Fine screening: the same as step (4) of Example 1.

[0051] Comparative Example 3

[0052] Compared with Example 1, the difference is that the gradient combined screening is not performed on the second combined drum screen of step (4), and the specific step (4) is: the dried material is air-selected to obtain a third air-selected heavy material and a third air-selected light material, the third air-selected heavy material is magnetically separated and separated by a magnetic separator to obtain metal materials and bone materials, and the third air-selected light material is mixed and packaged by a baler to obtain finely screened and packaged materials.

[0053] The remaining parameters and operating steps remain unchanged.

[0054] Comparative Example 4

[0055] Compared with Example 1, the difference is that the hot air blower in step (2) is not turned on, and the other parameters and operating steps remain unchanged.

[0056] Performance testing

[0057] (1) The sizes of the first homogeneous material and the second homogeneous material after the air separation and crushing treatment in step (2) were observed and recorded by the operators. The results are shown in Table 1.

[0058] (2) Observe, record and calculate the effective utilization rate of the stored garbage in Examples 1-3 and Comparative Examples 1-4. The results are shown in Table 1.

[0059] Table 1

[0060]

[0061] As shown in Table 1, the present invention employs a pre-sorting combined with fine screening method to perform multiple sorting and screening processes on the landfill's stockpile. The process route is divided into pre-sorting mechanical treatment, biological drying treatment, and fine screening mechanical treatment. Different functional areas are simultaneously constructed, with pre-sorting serving as a reliable front-end pretreatment technology combined with fine screening to consolidate and improve the technology at the back end, forming a set of mutually complementary combined screening methods. Furthermore, the overall sorting specifications and destination of the stockpile are refined, enabling the effective utilization rate of the stockpile to reach 95%, significantly improving the utilization rate of the combined screening method for stockpile. Specifically, as can be seen from Comparative Examples 1-3, regardless of whether the pre-sorting step, the air separation, the crushing step, or the gradient combined screening step using the second combined drum screen are missing, the effective utilization rate of the stockpile is not as good as that of Examples 1-3, with the lack of the first combined drum screen and the second combined drum screen being particularly significant.

[0062] In addition, it can be seen from Comparative Example 4 that the present invention turns on the hot air blower in the crushing stage and adjusts the temperature to 50-55°C. The garbage is dried by forced hot air, which is beneficial to assist in the separation of the garbage, making the garbage more homogenized and convenient for subsequent processing. At the same time, forced hot air can also increase the effective utilization rate of the existing garbage to a certain extent.

[0063] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0064] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A combined screening method for stock garbage in a landfill, characterized in that: The combined screening method comprises the following steps: (1) Pre-sorting: The stock garbage in the landfill is loaded into the feeder by a forklift and transported to the sorting platform to obtain sorted materials, which are then sent to the first combined drum screen for pre-sorting to obtain the first oversize, the first midsize, and the first undersize; (2) Air separation and crushing: The first sieve material and the first sieve material are air separated respectively, and then moved to the crusher and crushed by adjusting the hot air temperature to obtain the first homogeneous material and the second homogeneous material respectively; (3) Biological drying: biologically drying the first undersize material, the first homogenized material, and the second homogenized material to obtain a dried material; (4) Fine screening: The dried material is sent to the second combined drum screen for screening, followed by air separation, magnetic separation and packaging to obtain the second undersize material, metal materials, bone materials and fine screening packaging materials; (5) Resource utilization: The obtained second screen undersize, metal materials, bone materials and fine screening packaged materials are recycled; The step (4) specifically comprises: feeding the dried processed material into a second combined drum screen for screening to obtain a second oversize material, a second midsize material, and a second undersize material; subjecting the second oversize material and the second midsize material to a third air separation and a fourth air separation respectively to obtain a third air separation heavy material, a third air separation light material, and a fourth air separation heavy material, and a fourth air separation light material; subjecting the third air separation heavy material and the fourth air separation heavy material to magnetic separation by a magnetic separator and separation to obtain metal materials and bone materials; and mixing and packaging the third air separation light material and the fourth air separation light material by a packaging machine to obtain finely screened packaging material; The step (2) specifically comprises: performing a first air separation and a second air separation on the first screen material and the first screen material, respectively, to obtain a first air separation heavy material, a first air separation light material, a second air separation heavy material, and a second air separation light material; mixing the first air separation heavy material, the second air separation heavy material, the first air separation light material, and the second air separation light material, respectively, and transferring them to a crusher; simultaneously turning on a hot air blower and adjusting the hot air temperature for crushing, to obtain a first homogeneous material and a second homogeneous material, respectively.

2. A combined screening method for stock waste in a landfill according to claim 1, characterized in that: In step (1), the first combined drum screen is a first combined drum screen in which drum screens with apertures of 180-190 mm and 90-100 mm are combined together, thereby forming a gradient combined screening.

3. The combined screening method for stock garbage in a landfill according to claim 1, characterized in that: The hot air temperature in step (2) is 50-55°C.

4. The combined screening method for stock waste in a landfill according to claim 1, characterized in that: The step (3) specifically comprises: randomly pushing and mixing the first undersize material, the first homogeneous material and the second homogeneous material to form a conical pile, covering the conical pile with a layer of transparent film, and heating, exhausting, ventilating and stirring the conical pile until drying is completed.

5. The combined screening method for stock waste in a landfill according to claim 4, characterized in that: The height of the conical stacking material is 2-2.4m, and the slope is 50-60°.

6. The combined screening method for stock waste in a landfill according to claim 4, characterized in that: The bottom end of the transparent film has a clearance height of 0.2-0.3m, and the top end has a clearance height of 0.4-0.6m.

7. The combined screening method for stock waste in a landfill according to claim 4, characterized in that: Step (4) The second combined drum screen is a drum screen with an aperture of 20-30 mm and a drum screen with an aperture of 60 mm combined together to form a gradient combined screening.

8. The combined screening method for stock waste in a landfill according to claim 1, characterized in that: The step (5) is specifically as follows: using the second screen undersize to prepare humus soil materials for plant cultivation, backfilling, covering landfills, and comprehensive utilization of soil resources required for non-food chain landscaping; recycling and reusing the separated metal materials as reusable materials by the material company through classification; grinding and crushing the bone materials into bone powder and bone ash materials for feed and fertilizer, or directly backfilling or as raw materials for environmentally friendly building materials; and making the finely screened baled materials into RDF as an environmentally friendly alternative fuel for cement plants, waste incineration power plants, and coal-fired power plants.

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