A smoldering-based in-situ waste landfill treatment system and method

Abstract

The application discloses a waste landfill site in-situ treatment system and method based on smoldering, and relates to the technical field of waste landfill treatment. The waste landfill site comprises a base and a solid waste landfill layer located on the base. The waste landfill site in-situ treatment system based on smoldering comprises: an igniter located between the base and the solid waste landfill layer; an air supply device for conveying air to the solid waste landfill layer and controlling the air flow rate; a temperature measuring device for measuring the temperature at different depth positions of the solid waste landfill layer; and a control terminal electrically connected with the air supply device and the temperature measuring device. The treatment system provided by the application can be used for in-situ smoldering treatment of waste in a waste landfill site, so that the waste decomposition speed can be improved, the waste decomposition period of the waste landfill site can be effectively shortened, and the existing waste landfill site close to saturation can be quickly and completely cleaned, so that the waste landfill site can be restored to the waste landfill capacity and be reused. The system provided by the application is simple to operate and suitable for waste landfill sites of different specifications.

Description

Technical Field

[0001] This invention relates to the field of landfill treatment technology, and in particular to an in-situ landfill treatment system and method based on smoldering combustion. Background Technology

[0002] Due to its simplicity and low cost, landfill remains the primary method of urban solid waste disposal, accounting for over 60% of all waste disposal. Currently, a large number of landfills are in operation in my country.

[0003] However, existing landfills have many drawbacks, including large land area requirements, foul odors, groundwater pollution, release of large amounts of greenhouse gases, primarily CH4 and CO2, and a high risk of fires and explosions. Furthermore, because the natural degradation of waste is very slow, typically taking several years, the landfill land has a long reuse cycle, and some land may even become unusable due to contamination, resulting in a waste of land resources. Therefore, how to quickly and efficiently manage the large number of existing landfills has become an urgent issue.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide an in-situ landfill treatment system and method based on smoldering, which aims to treat landfills quickly and efficiently.

[0006] The technical solution of the present invention is as follows:

[0007] A first aspect of the present invention provides a smoldering-based in-situ landfill remediation system, wherein the landfill includes a base and a solid waste landfill layer located on the base, and the smoldering-based in-situ landfill remediation system includes:

[0008] An igniter is located between the base and the solid waste landfill layer;

[0009] An air supply device for supplying air into the solid waste landfill layer and controlling the airflow rate;

[0010] A temperature measuring device is used to measure the temperature at different depths in a solid waste landfill layer.

[0011] Optionally, the air supply device includes:

[0012] Flow control equipment and air compressors;

[0013] A gas guide pipe, one end of which is connected in sequence to the flow control device and the air compressor, and the other end of which is inserted into the solid waste landfill layer.

[0014] Optionally, the air guide pipe includes a main air guide pipe and several branch air guide pipes. One end of the main air guide pipe is connected in sequence to the flow control device and the air compressor, and the other end of the main air guide pipe is connected to the several branch air guide pipes. The several branch air guide pipes are inserted into different positions in the solid waste landfill layer.

[0015] Optionally, the temperature measuring device includes:

[0016] Temperature recorder;

[0017] Several thermocouples, one end of which is electrically connected to the temperature recorder, and the other end of which is located at different depths in the solid waste landfill layer.

[0018] Optionally, the smoldering-based landfill in-situ treatment system further includes:

[0019] The control terminal is connected to both the flow control device and the temperature recorder.

[0020] A second aspect of the present invention provides a smoldering-based in-situ landfill remediation method, wherein the smoldering-based in-situ landfill remediation method employs the smoldering-based in-situ landfill remediation system of the present invention as described above, and the smoldering-based in-situ landfill remediation method includes the following steps:

[0021] The landfill is divided into several units, and each unit is further divided into several areas;

[0022] The waste is removed by smoldering in several areas of each unit in a cyclical manner, and new waste is then landfilled in the areas where the waste has been removed; or, the waste is removed by smoldering in several areas of each unit in a cyclical manner, resulting in a landfill after the waste has been removed.

[0023] Optionally, the smoldering treatment and waste removal steps specifically include:

[0024] Turn on the air supply device to deliver air into the solid waste landfill layer;

[0025] Turn on the igniter to ignite the waste in the solid waste landfill layer;

[0026] Smoldering of waste in solid waste landfills is controlled by an air supply system;

[0027] After the smoldering of waste in the solid waste landfill is completed, the remaining unburned waste is screened and removed.

[0028] Optionally, the step of screening and removing the remaining unburned waste specifically includes:

[0029] For metallic components, they are recycled after being screened by magnetic separation.

[0030] For sand, glass, ash from combustion, and unburned charcoal, after screening, they can be landfilled on-site, landfilled off-site, or recycled.

[0031] Alternatively, different units or areas can be separated from each other by digging trenches or erecting fireproof barriers.

[0032] Optionally, the smoldering-based in-situ landfill remediation method includes the following steps:

[0033] a. Divide the landfill into several units, and each unit into three areas, labeled as Area A, Area B, and Area C respectively;

[0034] b. The waste in area A is subjected to smoldering treatment. At this time, waste in areas B and C is landfilled.

[0035] c. After smoldering treatment in area A, the unburned waste is screened and removed. At the same time, the waste in area B is smoldered. Meanwhile, the waste in area C is landfilled.

[0036] d. Continue to landfill new garbage in area A after the garbage has been removed. At the same time, screen and remove the unburned garbage in area B after smoldering treatment, and smolder the garbage in area C.

[0037] e. After smoldering treatment in area C, unburned waste is screened and removed. At the same time, waste in area A is smoldered. At this time, waste in area B is landfilled.

[0038] f. Repeat steps c through e.

[0039] Beneficial Effects: In this invention, the igniter is used to trigger the smoldering of waste, the air supply device provides air to deep layers of waste to enable smoldering, and the temperature measuring device monitors the smoldering intensity at different depths in the solid waste landfill layer. The air supply device then controls the airflow rate to regulate the smoldering reaction intensity and spread rate. Therefore, the smoldering-based landfill in-situ treatment system provided by this invention can controllably treat landfill waste in smoldering conditions. Since the smoldering reaction rate is much higher than the biodegradation rate of waste, using the smoldering-based landfill in-situ treatment system provided by this invention can improve the waste decomposition rate, thereby effectively shortening the landfill waste decomposition cycle. This allows for the rapid and thorough cleaning of existing near-saturated landfills, restoring their landfill capacity for reuse, promoting the sustainable use of landfills, mitigating landfill fire and explosion accidents, and reducing the damage of existing landfill leachate to soil and water quality. Furthermore, the high temperature of smoldering (approximately 500°C) can convert most organic solid waste into substances harmless to the soil and kill pathogens within it. The smoldering-based in-situ landfill treatment system provided by this invention is simple to operate, consumes little energy during the treatment process, and is suitable for landfills of different sizes. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of a smoldering-based in-situ landfill treatment system.

[0041] Figure 2 A schematic diagram illustrating the smoldering process in various areas of a landfill.

[0042] Figure 3 This is a schematic diagram of a smoldering-based in-situ zoning treatment method for landfills.

[0043] Figure 4 This is a schematic diagram of another in-situ zoned treatment method for landfills based on smoldering combustion. Detailed Implementation

[0044] This invention provides a smoldering-based in-situ landfill treatment system and method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0046] Existing landfills have many drawbacks, including large land area requirements, foul odors, groundwater pollution, release of large amounts of greenhouse gases, primarily CH4 and CO2, and a high risk of fires and explosions. Furthermore, because the natural degradation of waste is very slow, typically taking several years, the landfill land has a long reuse cycle, and some land may even become unusable due to contamination, resulting in a waste of land resources. Therefore, how to quickly and efficiently treat the large number of existing landfills has become an urgent issue. While smoldering is a new technology for treating organic solid waste, current smoldering treatments are all carried out in reactors, inevitably requiring collection, transportation, and post-treatment processes. Based on this, this invention provides a system for controllable in-situ treatment of existing landfills using smoldering. Specifically, this invention provides a smoldering-based in-situ landfill treatment system, wherein, as... Figure 1 As shown, the landfill includes a base 1, a solid waste landfill layer 2 located on the base 1, and a soil cover layer 3 located on the solid waste landfill layer 2 (containing waste). The smoldering-based in-situ landfill treatment system includes:

[0047] Ignition device 4 is located between the base 1 and the solid waste landfill layer 2;

[0048] An air supply device is used to supply air into the solid waste landfill layer 2 and control the air flow rate.

[0049] A temperature measuring device is used to measure the temperature at different depths in the solid waste landfill layer 2.

[0050] In this embodiment of the invention, the igniter is used to trigger the smoldering of waste, the air supply device provides air to deep layers of waste to enable smoldering, and the temperature measuring device monitors the smoldering intensity at different depths of the solid waste landfill layer. The air supply device then controls the airflow rate to control the smoldering reaction intensity and spread rate. Therefore, the smoldering-based landfill in-situ treatment system provided by this invention can controllably treat landfill waste in smoldering conditions. Since the smoldering reaction rate is much higher than the biodegradation rate of waste, using the smoldering-based landfill in-situ treatment system provided by this invention can improve the waste decomposition rate, thereby effectively shortening the landfill waste decomposition cycle. This allows for the rapid and thorough cleaning of existing near-saturated landfills, restoring their landfill capacity for reuse, promoting the sustainable use of landfills, mitigating landfill fire and explosion accidents, and reducing the damage of existing landfill leachate to soil and water quality. Furthermore, the high temperature of smoldering (approximately 500°C) can convert most organic solid waste into substances harmless to the soil and kill pathogens within it. The smoldering-based in-situ landfill treatment system provided by this invention is simple to operate, consumes little energy during the treatment process, and is suitable for landfills of different sizes.

[0051] In some embodiments, the igniter is externally connected to a transformer ( Figure 1 (Not shown in the diagram) The ignition intensity of the igniter is controlled by adjusting the voltage and current. The ignition intensity can be adjusted according to the organic matter content, moisture content, degree of decomposition, and degree of compaction of the waste in the landfill being treated. Under normal circumstances, 100W of ignition power is sufficient to trigger a self-sustaining smoldering combustion. However, in cases where the waste moisture content is high and the degree of decomposition and compaction is significant, the ignition power can be increased and the ignition time extended.

[0052] In some implementations, such as Figure 1 As shown, the air supply device includes:

[0053] Flow control device 9 and air compressor 10;

[0054] The air guide pipe 5 is connected at one end to the flow control device 9 and the air compressor 10 in sequence, and the other end of the air guide pipe is inserted into the solid waste landfill layer 2.

[0055] In this embodiment, air is delivered to the solid waste landfill layer through an air duct. On the one hand, the air provides oxygen to the deep waste in the landfill layer to aid its smoldering; on the other hand, the air also serves to dry the waste. The flow control device (specifically, a flow meter) can control the air velocity within the air duct, and specifically, the intensity and spread rate of the smoldering reaction can be controlled by controlling the air velocity.

[0056] In some embodiments, the air duct 5 includes a main air duct 51 and a plurality of branch air ducts 52. One end of the main air duct 51 is connected in sequence to the flow control device 9 and the air compressor 10, and the other end of the main air duct 51 is connected to the plurality of branch air ducts 52. The plurality of branch air ducts 52 are inserted into different positions in the solid waste landfill layer 2.

[0057] In this embodiment, the arrangement of several branch air pipes can ensure that air can be introduced into each location of the solid waste landfill layer to ensure the uniformity of its smoldering.

[0058] In some implementations, such as Figure 1 As shown, the temperature measuring device includes:

[0059] Temperature recorder 7;

[0060] A plurality of thermocouples 6, one end of which is electrically connected to the temperature recorder 7, and the other end of which is disposed at different depths in the solid waste landfill layer.

[0061] Thermocouples are installed at different depths in the solid waste landfill layer to monitor the intensity of the smoldering reaction at these depths. Simultaneously, the airflow rate can be controlled via an air supply device to regulate the intensity and spread of the smoldering reaction. When the smoldering reaction is weak (when the temperature recorder shows a low temperature), the airflow rate is appropriately increased; conversely, the airflow rate is decreased.

[0062] In some implementations, such as Figure 1 As shown, the smoldering-based landfill in-situ treatment system further includes:

[0063] The control terminal 8 is electrically connected to the flow control device 9 and the temperature recorder 7. The control terminal (such as a computer) controls the flow control device and the temperature recorder, and records and saves the data.

[0064] This invention also provides a smoldering-based in-situ landfill remediation method, wherein the smoldering-based in-situ landfill remediation method employs the smoldering-based landfill remediation system described above in this invention, and the smoldering-based in-situ landfill remediation method includes the following steps:

[0065] The landfill is divided into several units, each unit is further divided into several areas, and each area is equipped with the smoldering-based landfill in-situ treatment system described above.

[0066] The waste is removed by smoldering in several areas of each unit in a cyclical manner, and new waste is then landfilled in the areas where the waste has been removed; or, the waste is removed by smoldering in several areas of each unit in a cyclical manner, resulting in a landfill after waste removal, i.e., landfill land after waste removal (which can be used for other purposes).

[0067] The method provided by this invention is simple to operate, safe, and low in cost, enabling in-situ treatment of landfill waste without the need for complex pretreatment, post-treatment, and transportation processes. Furthermore, by dividing the landfill into zones and performing smoldering treatment only on specific areas, the treatment process becomes safer and more controllable.

[0068] The method provided by this invention can improve the decomposition speed of waste, thereby effectively shortening the waste decomposition cycle of landfills. It can quickly and thoroughly clean up existing near-saturated landfills, releasing them and restoring their landfill capacity for reuse. This promotes the sustainable use of landfills and effectively solves problems such as the large area occupied by existing landfills, the fact that most landfills are nearing saturation, the slow processing speed of existing landfills, the frequent occurrence of landfill fires and explosions, and the harmful effects of landfill leachate on soil and water quality. Furthermore, the smoldering temperature (approximately 500°C) is high, which can convert most organic solid waste into substances harmless to the soil and kill pathogens within it.

[0069] In some implementations, such as Figure 2 As shown, the smoldering treatment and waste removal steps specifically include:

[0070] Turn on the air supply device to deliver air into the solid waste landfill layer;

[0071] Turn on the igniter to ignite the waste in the solid waste landfill layer (the smoldering surface spreads upwards from the bottom of the solid waste landfill layer);

[0072] Smoldering of waste in solid waste landfills is controlled by an air supply device (i.e., smoldering of waste in solid waste landfills is controlled by controlling the air flow rate).

[0073] After the smoldering of waste in the solid waste landfill is completed, the remaining unburned waste is screened and removed.

[0074] The step of screening and removing the remaining unburned waste specifically includes:

[0075] For metallic components, they are recycled after being screened by magnetic separation.

[0076] For sand, glass, ash from combustion, and unburned charcoal, after screening, they can be landfilled on-site, landfilled off-site, or recycled.

[0077] In this embodiment, such as Figure 2 As shown, the solid waste landfill layer serves as the smoldering treatment zone. Ignition is achieved using an igniter, and air is introduced to initiate smoldering. The intensity of the smoldering reaction at different depths is monitored by a temperature measuring device, while the airflow velocity is controlled by an air supply device to regulate the intensity and spread of the smoldering reaction, thus controlling combustion. When the smoldering reaction is weak (the temperature recorder shows a low temperature), the airflow velocity is appropriately increased; conversely, the airflow velocity is decreased. After smoldering in the solid waste landfill layer is complete, the remaining unburned waste is screened and removed. Specifically, metallic components are screened using magnetic separation for recycling; sand, glass, ash from combustion, and incompletely burned char are screened and then disposed of in-situ, off-site, or recycled, ultimately resulting in a new landfill area.

[0078] In some implementations, different units and areas are separated from each other by digging trenches or erecting fireproof barriers. This ensures that different units and areas of the landfill do not interfere with each other.

[0079] In some implementations, when the landfill needs to be reused, i.e., after the waste in the landfill is removed and new waste is refilled, such as... Figure 3 As shown, the smoldering-based in-situ landfill remediation method includes the following steps:

[0080] a. Divide the landfill into several units, each unit into three areas, labeled as Area A, Area B and Area C respectively (in step a, Area A, Area B and Area C are not limiting, but are labeled as Area A, Area B and Area C for ease of description). Each area is equipped with the smoldering-based landfill in-situ treatment system as described above.

[0081] b. The waste in area A is subjected to smoldering treatment. At this time, the waste in areas B and C is landfilled (including partially degraded waste and new waste that has not been degraded).

[0082] c. After smoldering treatment in area A, the unburned waste is screened and removed. At the same time, the waste in area B is smoldered. Meanwhile, the waste in area C is landfilled.

[0083] d. Continue to landfill new garbage in area A after the garbage has been removed. At the same time, screen and remove the unburned garbage in area B after smoldering treatment, and smolder the garbage in area C.

[0084] e. After smoldering treatment in area C, unburned waste is screened and removed. At the same time, waste in area A is smoldered. At this time, waste in area B is landfilled (that is, new waste is landfilled in area B after the waste has been removed).

[0085] f. Repeat steps c through e.

[0086] In this embodiment, different areas undergo different processing procedures simultaneously. Each area goes through a process of smoldering, screening and removing unburned waste, and landfilling of new waste, and this process is repeated in a cycle to ensure that each area is effectively utilized. Furthermore, only one area is smoldering at any given time (i.e., smoldering occurs in areas A, B, and C in a sequential cycle), making the processing safer and more controllable.

[0087] In step b, it is only for the convenience of describing that the smoldering treatment starts from area A. Of course, the smoldering treatment can start from area B or area C. In this invention, it is only necessary to start the smoldering treatment from one of the areas, and it is not limited to which specific area starts the smoldering treatment first.

[0088] The smoldering treatment in steps b to e is carried out using the smoldering-based landfill in-situ treatment system described above. This system involves igniting the waste using an igniter and introducing air into the solid waste landfill layer. The intensity and spread rate of the smoldering reaction are controlled by adjusting the flow rate of the introduced air, thereby achieving the smoldering and removal of the waste.

[0089] In some implementations, when the landfill is not required to be reused, i.e., after the waste in the landfill is removed and no new waste is refilled, such as... Figure 4 As shown, the smoldering-based in-situ landfill remediation method includes the following steps:

[0090] a1. Divide the landfill into several units, and each unit into three areas, labeled as Area A, Area B and Area C respectively;

[0091] b1. The waste in area A is subjected to smoldering treatment. At this time, the waste in areas B and C is landfilled (including partially degraded waste and new waste that has not been degraded).

[0092] c1. After smoldering treatment in area A, the unburned waste is screened and removed. At the same time, the waste in area B is smoldered. Meanwhile, the waste in area C is landfilled.

[0093] d1. Screen and remove the unburned waste after smoldering treatment in area B, and perform smoldering treatment on the waste in area C;

[0094] Finally, the unburned waste after smoldering treatment in area C is screened and removed. In this way, all the waste in areas A, B and C can be cleaned up, and no landfill area is left.

[0095] In summary, this invention provides a smoldering-based in-situ landfill treatment system and method. The igniter triggers the smoldering of the waste, an air supply device provides air to deep layers of waste to enable smoldering, and a temperature measurement device monitors the smoldering intensity at different depths in the solid waste landfill layer. The air supply device then controls the airflow rate to regulate the smoldering reaction intensity and spread rate. Therefore, the smoldering-based in-situ landfill treatment system provided by this invention allows for controllable smoldering treatment of landfill waste. Since the smoldering reaction rate is much higher than the biodegradation rate of waste, using this system can improve waste decomposition speed, effectively shorten the landfill decomposition cycle, and quickly and thoroughly clean up near-saturated landfills, restoring their landfill capacity for reuse. This promotes the sustainable use of landfills, mitigates landfill fire and explosion accidents, and reduces the damage of existing landfill leachate to soil and water quality. Furthermore, the high temperature of smoldering can convert most organic solid waste into substances harmless to the soil and kill pathogens within it. The smoldering-based in-situ landfill treatment system provided by this invention is simple to operate, consumes little energy during the treatment process, and is suitable for landfills of different sizes.

[0096] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for in-situ landfill remediation based on smoldering combustion, characterized in that, The landfill includes a base, a solid waste landfill layer located on the base, and a soil cover layer located on the solid waste landfill layer. The smoldering-based in-situ landfill remediation method employs a smoldering-based in-situ landfill remediation system, which includes: An igniter is located between the base and the solid waste landfill layer; the igniter is externally connected to a transformer, and the ignition intensity of the igniter is controlled by controlling the voltage and current. An air supply device is used to supply air into the solid waste landfill layer and control the air flow rate; the air supply device includes a flow control device. A temperature measuring device is used to measure the temperature at different depths in a solid waste landfill layer; the temperature measuring device includes: Temperature recorder; A plurality of thermocouples, one end of which is electrically connected to the temperature recorder, and the other end of which is disposed at different depths in the solid waste landfill layer; The control terminal, wherein the flow control device and the temperature recorder are electrically connected to the control terminal respectively; The smoldering-based in-situ landfill remediation method includes the following steps: a. Divide the landfill into several units, and each unit into three areas, labeled as Area A, Area B, and Area C respectively; b. The waste in area A is subjected to smoldering treatment. At this time, waste in areas B and C is landfilled. c. After smoldering treatment in area A, the unburned waste is screened and removed. At the same time, the waste in area B is smoldered. Meanwhile, the waste in area C is landfilled. d. Continue to landfill new garbage in area A after the garbage has been removed. At the same time, screen and remove the unburned garbage in area B after smoldering treatment, and smolder the garbage in area C. e. Screen and remove the unburned waste after smoldering treatment in area C, and at the same time smolder the waste in area A. At this time, landfill the waste in area B; f. Repeat steps c to e.

2. The in-situ landfill remediation method based on smoldering according to claim 1, characterized in that, The specific steps for screening and removing unburned waste include: For metallic components, they are recycled after being screened by magnetic separation. For sand, glass, ash from combustion, and unburned charcoal, after screening, they can be landfilled on-site, landfilled off-site, or recycled.

3. The in-situ landfill remediation method based on smoldering according to claim 1, characterized in that, Different units and areas are separated from each other by digging trenches or erecting fireproof barriers.

4. The in-situ landfill remediation method based on smoldering according to claim 1, characterized in that, The air supply device also includes: Air compressor; A gas guide pipe, one end of which is connected in sequence to the flow control device and the air compressor, and the other end of which is inserted into the solid waste landfill layer.

5. The in-situ landfill remediation method based on smoldering according to claim 4, characterized in that, The air guide pipe includes a main air guide pipe and several branch air guide pipes. One end of the main air guide pipe is connected to the flow control device and the air compressor in sequence, and the other end of the main air guide pipe is connected to the several branch air guide pipes. The several branch air guide pipes are inserted into different positions in the solid waste landfill layer.

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