A method for applying an in situ enhanced extraction volatile contaminant remediation system

Abstract

The application discloses an application method of an in-situ synergistic extraction volatile pollutant remediation system, and the remediation system comprises a waterproof layer arranged between a groundwater layer and a pollution area, a synergistic thermal desorption assembly arranged in the pollution area, and a gas-phase extraction pipe arranged in the pollution area; the synergistic thermal desorption assembly comprises a synergistic outer pipe, a synergistic inner pipe and an aeration connecting pipe connected between the synergistic outer pipe and the synergistic inner pipe. Through arrangement of the synergistic thermal desorption assembly, the application is applied to thermal desorption of the polluted soil layer in the pollution area by partition arrangement of the partition base plate, and heat loss is reduced; through the arrangement form of the inner pipe and the outer pipe, a closed high-temperature liquid space is formed for soil heating; through arrangement of the aeration connecting pipe, high-temperature aeration can be introduced, so that precise aeration application is realized; in addition, through arrangement of the water extraction pipe and the gas-phase extraction pipe interlayer, the gas-phase pollutants can be prevented from condensing and kept in a gas-phase state in the transmission process, so that efficient treatment is facilitated.

Description

Technical Field

[0001] This invention relates to the field of water and soil pollution remediation technology, and in particular to an application method of an in-situ enhanced extraction and remediation system for volatile pollutants. Background Technology

[0002] Vapor phase extraction (VPE) is a commonly used method for removing volatile organic pollutants (VOCs) from soil. However, VPE remediation often suffers from tailing and incomplete treatment. To ensure extraction effectiveness, chemical dosing or thermal desorption are commonly used as supplementary methods. However, thermal desorption is a limited approach, merely heating the well or pipe, resulting in a limited radiation range and significant heat waste, making its auxiliary efficiency for VPE low. Therefore, precise heating based on the contaminated area and the area requiring supplemental heating, along with the use of multiple heating technologies while ensuring VPE efficiency, especially in environments containing groundwater, requires targeted design. Summary of the Invention

[0003] This invention provides an application method for an in-situ enhanced extraction and remediation system for volatile pollutants, which addresses technical issues such as in-situ zoned enhanced heating design, comprehensive and precise heating, and temperature control adapted to gas phase pollutants during the gas phase extraction of volatile pollutants from soil containing groundwater.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: An application method for an in-situ enhanced extraction volatile pollutant remediation system, the remediation system comprising an impermeable layer between the groundwater layer and the contaminated area, an enhanced thermal desorption component disposed within the contaminated area, and a gas phase extraction pipe disposed within the contaminated area; The enhanced thermal desorption assembly includes an enhanced outer tube, an enhanced inner tube, and an aeration connecting tube that connects the enhanced outer tube and the enhanced inner tube. The application method of the in-situ enhanced extraction and remediation system for volatile pollutants is as follows: S1. Based on the determined contaminated area, the soil is divided into an overlying soil layer and a contaminated soil layer, and an impermeable layer is installed above the groundwater layer. S2. Install gas phase extraction pipes and enhanced thermal desorption components within the contaminated area; a closed thermal stability zone is formed between the inner and outer enhanced pipes, and a branch aeration pipe is inserted into the inner enhanced pipe; a water injection pipe and a water extraction pipe are respectively installed at the top of the thermal stability zone. S3. When the temperature measured in the contaminated soil layer is lower than the gas phase extraction standard, the contaminated area is heated; high-temperature liquid is injected into the thermally stable zone through the water injection pipe to heat the enhanced outer pipe; water is pumped out and sampled in the pumping pipe, and the pumping pipe is closed after the temperature of the extracted liquid meets the design requirements. S4. All aeration branch pipes are connected in parallel to the main aeration pipe, and heated air is injected into the main aeration pipe; hot air is injected into the contaminated soil layer in an intermittent aeration manner; the positions of the aeration connecting pipes are pre-set for directional and fixed-height aeration; S5. Stop the aeration interval and perform gas phase extraction through the gas phase extraction pipe; the gas phase extraction pipe is a double-layer pipe; the branch pipe of the pumping pipe is connected to the interlayer of the double-layer pipe; the high-temperature liquid extracted by the pumping pipe keeps the pollutants in the double-layer pipe in a gas phase state. S6. The temperature in the thermal stability zone and the temperature in the extraction pipe interlayer are kept stable by circulating water injection. After repeated intermittent aeration and gas phase extraction, the remediation of volatile pollutants is completed.

[0005] Furthermore, the horizontal range of the impermeable layer is larger than the horizontal projection range of the contaminated area; the impermeable layer is formed by drilling and grouting before the gas phase extraction begins.

[0006] Furthermore, the length and position of the enhancement outer pipe correspond to the overlying soil layer and the contaminated soil layer, and the length and position of the enhancement inner pipe correspond to the contaminated soil layer; a partition plate is provided at the top connection of the enhancement outer pipe and the enhancement inner pipe, and the space inside the enhancement outer pipe that is higher than the enhancement inner pipe is the enhancement vacancy area.

[0007] Furthermore, the partition substrate includes a main substrate, an aeration pipe perforation disposed at the center of the main substrate, and water injection pipe perforations and water pumping pipe perforations disposed on both sides of the aeration pipe perforation. The perforation of the aeration pipe corresponds to the connection of the branch aeration pipe, and the perforation of the water injection pipe and the perforation of the water pumping pipe correspond to the connection of the water injection pipe and the water pumping pipe, respectively.

[0008] Furthermore, the branch aeration pipes are provided with aeration holes at intervals in both the vertical and circumferential directions, and the distance between adjacent aeration holes is no greater than the distance between adjacent aeration connecting pipes; a sealing ring is also provided between the branch aeration pipes and the aeration pipe perforations. The branch aeration pipe is connected to the main aeration pipe, which is also equipped with a heater. The main aeration pipe is connected to the aeration pump, and the heating temperature corresponds to the designed air heating temperature.

[0009] Furthermore, aeration valves are installed at intervals on the branch aeration pipes, and an aeration baffle is installed below each aeration valve; the baffle is a circular sealing plate; during aeration, the opening and closing of the valves are adjusted to control the aeration flow rate and aeration height.

[0010] Furthermore, the enhanced thermal desorption components are at least installed at the boundary of the contaminated area and within the contaminated area; the enhanced thermal desorption components within the contaminated area aerate in the circumferential direction of the enhanced outer pipe, and the aeration connecting pipes are spaced apart in the circumferential direction; the enhanced thermal desorption components at the boundary of the contaminated area aerate in the direction of the enhanced outer pipe facing the contaminated area, and the aeration connecting pipes are spaced apart on the side facing the contaminated area.

[0011] Furthermore, the gas phase extraction tube includes a gas phase extraction main pipe and gas phase extraction holes spaced apart on the gas phase extraction main pipe; the gas phase extraction holes are arranged within the contaminated area to be extracted. The gas phase extraction main pipe is connected to the inner pipe of the extraction pipeline, and the extraction pipeline is also equipped with a water outlet pipe. A temperature measuring device is installed at the water outlet pipe. If the temperature inside the extraction pipeline jacket is lower than the set temperature, high-temperature liquid is added through the water pump pipe or external heating measures are used to raise the temperature.

[0012] Furthermore, the water injection pipe is connected to the water injection pump via a pipeline, and the water extraction pipe is connected to the water extraction pump via a pipeline; valves are installed on all pipelines; the branch pipes of each water extraction pipe are connected in parallel to the extraction pipe, and valves are installed on each branch pipe.

[0013] Furthermore, a combined extraction and monitoring pipe is installed downstream of the groundwater layer and downstream of the impermeable layer; the bottom of the monitoring pipe is located above the groundwater layer and extracts groundwater for testing; if pollutants are detected in the groundwater, liquid phase extraction is performed; the extracted liquid enters a gas-liquid separation device; the separated gaseous pollutants are transported in parallel with the gaseous pollutants in the gas phase extraction pipe to a gas collection and treatment device; the liquid pollutants enter a liquid collection device.

[0014] The beneficial effects of this invention are reflected in: This invention utilizes an enhanced thermal desorption component, employing a partitioned substrate to strategically desorb contaminated soil layers within specific contaminated areas, thereby minimizing heat loss. The internal and external pipe configuration creates a closed, high-temperature liquid space for soil heating. The aeration connecting pipes allow for the introduction of high-temperature aeration, enabling precise aeration through directional and height-controlled processes. Furthermore, the interlayer between the pumping pipe and the gas phase extraction pipe helps prevent condensation of gaseous pollutants during transport, maintaining their gaseous state for efficient treatment. This invention solves the technical problems of in-situ zoned enhanced heating design, comprehensive and precise heating, and temperature control adapted to gaseous pollutants during gas phase extraction of volatile pollutants from soil containing groundwater. Other features and advantages of this invention will be set forth in the following description and will be apparent in part from the description, or may be learned by practicing the invention; the main objectives and other advantages of this invention can be realized and obtained by means of the methods particularly pointed out in the description. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the application of an in-situ enhanced extraction and remediation system for volatile pollutants. Figure 2 This is a schematic diagram of the enhanced thermal desorption component and its connection structure; Figure 3 This is a schematic diagram of the partition substrate structure; Figure 4 This is a schematic diagram of the aeration baffle structure; Figure 5 This is a schematic diagram of the gas phase extraction tube structure.

[0016] Figure reference numerals: 1-Overlying soil layer, 2-Contaminated soil layer, 3-Groundwater layer, 4-Contaminated area, 5-Imperile layer, 6-Enhanced thermal desorption component, 61-Enhanced outer pipe, 62-Enhanced inner pipe, 63-Separating base plate, 631-Main base plate, 632-Perforated aeration pipe, 633-Perforated water injection pipe, 634-Perforated pumping pipe, 64-Enhanced vacant area, 65-Aeration connecting pipe, 66-Thermal stable zone, 67-Aeration baffle, 7-Gas phase extraction Pipe, 71-Main gas phase extraction pipe, 72-Gas phase extraction hole, 8-Aeration pump, 9-Heater, 10-Main aeration pipe, 11-Branch aeration pipe, 12-Water injection pipe, 13-Water pumping pipe, 14-Water injection pump, 15-Water pumping pump, 16-Gas-liquid separation device, 17-Liquid collection device, 18-Gas collection and treatment device, 19-Extraction pipeline, 20-Valve, 21-Outlet pipe, 22-Extraction monitoring combination pipe, 23-Aeration valve. Detailed Implementation

[0017] The technical solutions of the present invention will be described in detail below through embodiments. The following embodiments are merely exemplary and can only be used to explain and illustrate the technical solutions of the present invention, and should not be construed as limiting the technical solutions of the present invention.

[0018] Taking an oil pipeline leak as an example, the pipeline is buried in the soil. Once a leak occurs, a large amount of volatile organic compounds such as benzene from the oil will be stored in the soil in the gaseous phase. Figures 1 to 5 As shown, the in-situ enhanced extraction volatile pollutant remediation system includes an impermeable layer 5 installed between the groundwater layer 3 and the contaminated zone 4, an enhanced thermal desorption component 6 installed within the contaminated zone 4, and a gas phase extraction pipe 7 installed within the contaminated zone 4. The enhanced thermal desorption component 6 includes an enhanced outer pipe 61, an enhanced inner pipe 62, and an aeration connecting pipe 65 connecting the enhanced outer pipe 61 and the enhanced inner pipe 62.

[0019] Combination Figures 1 to 5 As shown, the application method of the in-situ enhanced extraction volatile pollutant remediation system includes the following specific steps: S1. Based on the defined contaminated area 4, the soil is divided into an overlying soil layer 1 and a contaminated soil layer 2, and an impermeable layer 5 is installed above the groundwater layer 3. The horizontal range of the impermeable layer 5 is larger than the horizontal projection range of the contaminated area 4; the impermeable layer 5 is formed by drilling and grouting before the start of gas phase extraction.

[0020] S2. A gas phase extraction pipe 7 and an enhanced thermal desorption component 6 are installed in the contaminated zone 4. A closed thermal stability zone 66 is formed between the enhanced inner pipe 62 and the enhanced outer pipe 61. An aeration pipe 11 is inserted into the enhanced inner pipe 62. A water injection pipe 12 and a water extraction pipe 13 are respectively installed at the top of the thermal stability zone 66.

[0021] The length and position of the enhancement outer pipe 61 correspond to the overlying soil layer 1 and the contaminated soil layer 2, and the length and position of the enhancement inner pipe 62 correspond to the contaminated soil layer 2. A partition plate 63 is provided at the top connection of the enhancement outer pipe 61 and the enhancement inner pipe 62, and the space inside the enhancement outer pipe 61 above the enhancement inner pipe 62 is the enhancement empty area 64. The partition plate 63 includes a main plate 631, an aeration pipe perforation 632 located at the center of the main plate 631, and water injection pipe 12 perforation 633 and water pumping pipe 13 perforation 634 located on both sides of the aeration pipe perforation 632. The aeration pipe perforation 632 is connected to the branch aeration pipe 11, and the water injection pipe 12 perforation 633 and water pumping pipe 13 perforation 634 are connected to the water injection pipe 12 and the water pumping pipe 13, respectively.

[0022] S3. When the temperature measured in the contaminated soil layer 2 is lower than the gas phase extraction standard, the contaminated area 4 is heated; high-temperature liquid is injected into the thermally stable zone 66 through the water injection pipe 12 to heat the enhancement outer pipe 61; water is pumped and sampled in the pumping pipe 13, and the pumping pipe 13 is closed after the temperature of the pumped liquid meets the design requirements.

[0023] S4. All aeration branch pipes are connected in parallel to the main aeration pipe 10, and heated air is injected into the main aeration pipe 10. Hot air is injected into the contaminated soil layer 2 in an intermittent aeration manner. The position of the aeration connecting pipe 65 is set in advance for directional and fixed-height aeration.

[0024] In this embodiment, the branch aeration pipe 11 is provided with aeration holes at intervals in both the vertical and circumferential directions, and the distance between adjacent aeration holes is not greater than the distance between adjacent aeration connecting pipes 65; a sealing ring is also provided between the branch aeration pipe 11 and the aeration pipe through hole 632; a heater 9 is also provided on the main aeration pipe 10 connected to the branch aeration pipe 11, and the main aeration pipe 10 is connected to the aeration pump 8, and the heating temperature corresponds to the designed air heating temperature.

[0025] In this embodiment, aeration valves 23 are spaced apart on the branch aeration pipe 11, and an aeration baffle 67 is provided below each aeration valve 23; the aeration baffle 67 is a circular sealing support plate, used to enhance the partitioning of the inner pipe 62 and support the installation of the branch aeration pipe 11; during aeration, the opening and closing of the valve 20 is adjusted to control the aeration flow rate and aeration height.

[0026] In addition, the enhanced thermal desorption components 6 are at least located at the boundary of the polluted zone 4 and within the polluted zone 4; the enhanced thermal desorption components 6 within the polluted zone 4 aerate in the circumferential direction of the enhanced outer pipe 61, and the aeration connecting pipes 65 are spaced apart in the circumferential direction; the enhanced thermal desorption components 6 at the boundary of the polluted zone 4 aerate in the direction of the enhanced outer pipe 61 facing the polluted zone 4, and the aeration connecting pipes 65 are spaced apart on the side facing the polluted zone 4.

[0027] In this embodiment, the water injection pipe 12 is connected to the water injection pump 14 via a pipe, the water injection pump 14 is connected to the water supply source and the water is preheated, the water extraction pipe 13 is connected to the water extraction pump 15 via a pipe, and the water extraction pump 15 is also connected to the recycling pool; each pipe is equipped with a valve 20; the branch pipes of each water extraction pipe 13 are connected in parallel to the extraction pipe 19, and each branch pipe is equipped with a valve 20.

[0028] S5. Stop the aeration interval and perform gas phase extraction in the gas phase extraction pipe 7; the gas phase extraction pipe 19 is a double-layer pipe; the branch pipe of the water pumping pipe 13 is connected to the interlayer of the double-layer pipe; the high-temperature liquid extracted by the water pumping pipe 13 keeps the pollutants in the double-layer pipe in a gas phase state.

[0029] In this embodiment, the gas phase extraction tube 7 includes a gas phase extraction main tube 71 and gas phase extraction holes 72 spaced apart on the gas phase extraction main tube 71; the gas phase extraction holes 72 are disposed within the contaminated area 4 to be extracted; the gas phase extraction main tube 71 is connected to the inner pipe of the extraction pipe 19, and the extraction pipe 19 is also provided with a water outlet pipe 21; a temperature measuring device is provided at the water outlet pipe 21, and if the temperature inside the interlayer of the extraction pipe 19 is lower than the set temperature, high-temperature liquid is added through the water pumping pipe 13 or external heating measures are used to raise the temperature.

[0030] The temperatures in S6, the thermal stability zone 66, and the interlayer of the extraction pipe 19 are kept stable by circulating water injection. After repeated intermittent aeration and gas phase extraction, the remediation of volatile pollutants is completed.

[0031] In application, an extraction and monitoring combination pipe 22 is installed downstream of the groundwater layer 3 and downstream of the impermeable layer 5. The bottom of the monitoring combination pipe is located above the groundwater layer 3, and groundwater is extracted for detection. If pollutants are detected in the groundwater, liquid phase extraction is performed. The extracted liquid enters the gas-liquid separation device 16. The separated gaseous pollutants are transferred in parallel with the gaseous pollutants in the gas extraction pipe 7 to the gas collection and treatment device 18. The liquid pollutants enter the liquid collection device 17.

[0032] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An application method for an in-situ enhanced extraction and remediation system for volatile pollutants, characterized in that, The remediation system includes an impermeable layer between the groundwater layer and the contaminated area, an enhanced thermal desorption assembly installed in the contaminated area, and a gas extraction pipe installed in the contaminated area. The enhanced thermal desorption assembly includes an enhanced outer tube, an enhanced inner tube, and an aeration connecting tube that connects the enhanced outer tube and the enhanced inner tube. The application method of the in-situ enhanced extraction and remediation system for volatile pollutants is as follows: S1. Based on the determined contaminated area, the soil is divided into an overlying soil layer and a contaminated soil layer, and an impermeable layer is installed above the groundwater layer. S2. Install gas phase extraction pipes and enhanced thermal desorption components within the contaminated area; a closed thermal stability zone is formed between the inner and outer enhanced pipes, and a branch aeration pipe is inserted into the inner enhanced pipe; a water injection pipe and a water extraction pipe are respectively installed at the top of the thermal stability zone. S3. When the temperature measured in the contaminated soil layer is lower than the gas phase extraction standard, the contaminated area is heated; high-temperature liquid is injected into the thermally stable zone through the water injection pipe to heat the enhanced outer pipe; water is pumped out and sampled in the pumping pipe, and the pumping pipe is closed after the temperature of the extracted liquid meets the design requirements. S4. All aeration branch pipes are connected in parallel to the main aeration pipe, and heated air is injected into the main aeration pipe; hot air is injected into the contaminated soil layer in an intermittent aeration manner; the positions of the aeration connecting pipes are pre-set for directional and fixed-height aeration; S5. Stop the aeration interval and perform gas phase extraction through the gas phase extraction pipe; the gas phase extraction pipe is a double-layer pipe; the branch pipe of the pumping pipe is connected to the interlayer of the double-layer pipe; the high-temperature liquid extracted by the pumping pipe keeps the pollutants in the double-layer pipe in a gas phase state. S6. The temperature in the thermal stability zone and the temperature in the extraction pipe interlayer are kept stable by circulating water injection. After repeated intermittent aeration and gas phase extraction, the remediation of volatile pollutants is completed.

2. The application method of the in-situ enhanced extraction volatile pollutant remediation system as described in claim 1, characterized in that, The horizontal range of the impermeable layer is larger than the horizontal projection range of the contaminated area; the impermeable layer is formed by drilling and grouting before the start of gas phase extraction.

3. The application method of the in-situ enhanced extraction volatile pollutant remediation system as described in claim 1, characterized in that, The length and position of the enhancement outer pipe correspond to the overlying soil layer and the contaminated soil layer, while the length and position of the enhancement inner pipe correspond to the contaminated soil layer. A partition plate is provided at the top connection of the enhancement outer pipe and the enhancement inner pipe, and the space inside the pipe where the enhancement outer pipe is higher than the enhancement inner pipe is the enhancement vacancy area.

4. The application method of the in-situ enhanced extraction volatile pollutant remediation system as described in claim 3, characterized in that, The partition substrate includes a main substrate, an aeration pipe perforation disposed at the center of the main substrate, and water injection pipe perforations and water pumping pipe perforations disposed on both sides of the aeration pipe perforation. The perforation of the aeration pipe corresponds to the connection of the branch aeration pipe, and the perforation of the water injection pipe and the perforation of the water pumping pipe correspond to the connection of the water injection pipe and the water pumping pipe, respectively.

5. The application method of the in-situ enhanced extraction volatile pollutant remediation system as described in claim 1, characterized in that, The branch aeration pipes are provided with aeration holes at intervals in both the vertical and circumferential directions, and the distance between adjacent aeration holes is no greater than the distance between adjacent aeration connecting pipes; a sealing ring is also provided between the branch aeration pipes and the aeration pipe perforations. The branch aeration pipe is connected to the main aeration pipe, which is also equipped with a heater. The main aeration pipe is connected to the aeration pump, and the heating temperature corresponds to the designed air heating temperature.

6. The application method of the in-situ enhanced extraction volatile pollutant remediation system as described in claim 1, characterized in that, Aeration valves are installed at intervals on the branch aeration pipes, and an aeration baffle is installed below each aeration valve; the baffle is a circular sealing plate; during aeration, the opening and closing of the valves are adjusted to control the aeration flow rate and aeration height.

7. The application method of the in-situ enhanced extraction volatile pollutant remediation system as described in claim 1, characterized in that, The enhanced thermal desorption components are installed at least at the boundary of the polluted area and within the polluted area. The enhanced thermal desorption components within the polluted area aerate in the circumferential direction of the enhanced outer pipe, and the aeration connecting pipes are spaced apart in the circumferential direction. The enhanced thermal desorption components at the boundary of the polluted area aerate in the direction of the enhanced outer pipe facing the polluted area, and the aeration connecting pipes are spaced apart on the side facing the polluted area.

8. The application method of the in-situ enhanced extraction volatile pollutant remediation system as described in claim 1, characterized in that, The gas phase extraction tube includes a gas phase extraction main tube and gas phase extraction holes spaced apart on the gas phase extraction main tube; the gas phase extraction holes are arranged in the contaminated area corresponding to the extraction. The gas phase extraction main pipe is connected to the inner pipe of the extraction pipeline, and the extraction pipeline is also equipped with a water outlet pipe. A temperature measuring device is installed at the water outlet pipe. If the temperature inside the extraction pipeline jacket is lower than the set temperature, high-temperature liquid is added through the water pump pipe or external heating measures are used to raise the temperature.

9. The application method of the in-situ enhanced extraction volatile pollutant remediation system as described in claim 1, characterized in that, The water injection pipe is connected to the water injection pump via a pipeline, and the water extraction pipe is connected to the water extraction pump via a pipeline; valves are installed on each pipeline; the branch pipes of each water extraction pipeline are connected in parallel to the extraction pipeline, and valves are installed on each branch pipe.

10. The application method of the in-situ enhanced extraction volatile pollutant remediation system as described in claim 1, characterized in that, Downstream of the groundwater layer and downstream of the impermeable layer, an extraction and monitoring combination pipe is installed; the bottom of the monitoring combination pipe is located above the groundwater layer and extracts groundwater for testing; if pollutants are detected in the groundwater, liquid phase extraction is performed; the extracted liquid enters the gas-liquid separation device; the separated gaseous pollutants are transported in parallel with the gaseous pollutants in the gas phase extraction pipe to the gas collection and treatment device. Liquid contaminants enter the liquid collection device.

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