Method for groundwater pollution extraction treatment based on elastic water release

Abstract

The application relates to a groundwater pollution extraction treatment method based on elastic water release, and belongs to the technical field of groundwater pollution treatment. The method comprises the following steps: arranging multiple pressure points in a pollution source area, arranging multiple water extraction wells in a downstream boundary area of the pollution source area through which groundwater flows; performing multiple pressurizations on the multiple pressure points within a preset time length; when the last pressurization is performed within the preset time length, the multiple water extraction wells are controlled to start water extraction; after the water level of the pollution source area is lowered to a preset depth below an undisturbed water level and maintained for a preset time length, the multiple water extraction wells are controlled to stop water extraction, and the pressure of the pressure points is unloaded; when the water level of the pollution source area is restored to the undisturbed water level again, the step of performing multiple pressurizations on the multiple pressure points within the preset time length is repeated until the pollution concentration of the extracted groundwater meets a preset condition, so that the water level of the pollution source area is raised and a water mound is formed. The application can improve the problems of tailing and rebound in the extraction treatment of groundwater pollution.

Description

Technical Field

[0001] This application relates to the field of groundwater pollution control technology, and in particular to a groundwater pollution extraction and treatment method based on elastic water release. Background Technology

[0002] Pump and treat (P&T) is a widely used method for groundwater remediation, with extensive practical application both domestically and internationally. This technology involves constructing pumping wells in the contaminated area to extract the contaminated groundwater to the surface, where it is then treated using physical, chemical, or biological methods to achieve purification. It is suitable for situations with high contaminant concentrations requiring rapid treatment.

[0003] However, the application of this technology has always had two problems: one is the "tailing" of pollutants, that is, after a period of extraction and treatment, the concentration of pollutants in groundwater begins to decrease significantly, but later remains at a concentration higher than the safe value and no longer decreases significantly; the other is the "rebound" of pollutants, that is, after extraction stops in the later stage, the concentration of pollutants in groundwater increases.

[0004] The main reason for the above problems lies in the adsorption and desorption of pollutants on the soil. In the vadose zone of the soil (the area between the surface and the groundwater level, where the soil or rock contains both air and moisture), pollutants can interact with soil debris particles through various pathways, including adsorption, desorption, volatilization, diffusion, and biodegradation. Adsorption is the process of pollutants binding to the surface of debris particles, temporarily immobilizing them and reducing their mobility in the environment; the loose pores of the vadose zone become a temporary "warehouse" for pollutants. Desorption, on the other hand, is the process of pollutants being released from the surface of debris particles back into the solution, which may lead to the re-migration and diffusion of pollutants.

[0005] The increase or decrease in the amount of water extracted, as well as the distribution of extraction wells, only affects the increase or decrease in lateral inflow, but has no effect on pollutants adsorbed by debris particles. The decrease in water head caused by extraction actually increases the thickness of the local vadose zone, making pollutant desorption more difficult. Therefore, traditional extraction methods are insufficient to fundamentally solve the problems of tailing and rebound, significantly impacting the effectiveness of groundwater pollution remediation. Summary of the Invention

[0006] To address the issues of tailing and rebound in groundwater pollution extraction and treatment, this application provides a groundwater pollution extraction and treatment method based on elastic water release.

[0007] This application provides a groundwater pollution extraction and treatment method based on elastic water release, which adopts the following technical solution:

[0008] Multiple pressure points are set up in the pollution source area, and multiple pumping wells are set up in the downstream boundary area where groundwater flows through the pollution source area;

[0009] Within the preset duration The system applies pressure to the multiple pressure points repeatedly to raise the water level in the pollution source area and form a water mound.

[0010] During the preset time During the final pressurization, the multiple pumping wells are controlled to start pumping water to lower the water level in the pollution source area.

[0011] Adjust the pumping speed to lower the water level in the pollution source area to a preset depth below the undisturbed water level and maintain this level for a preset duration. Then, control the multiple pumping wells to stop pumping water and unload the pressure at the pressure application point;

[0012] After the pressure at the pressure point is released, a water level funnel forms in the pollution source area. When the water level in the pollution source area returns to the undisturbed level, the process is repeated for a preset time. The process involves applying pressure to multiple pressure points repeatedly to raise the water level in the pollution source area and form a water mound, until the pollutant concentration in the extracted groundwater meets preset conditions.

[0013] Optionally, the influence range of the plurality of pressure points covers the range of the pollution source area; the number of pressure points is determined by the influence radius of a single pressure point and the range of the pollution source area.

[0014] Optionally, the radius of influence of the single pressure point is equal to the burial depth of the aquifer top plate.

[0015] Optionally, if the depth of the contaminated layer does not exceed 10 meters, the pressure applied at a single pressure point shall not be less than 20 tons; if the depth of the contaminated layer exceeds 10 meters, the pressure applied at a single pressure point shall not be less than 50 tons.

[0016] Optionally, the capture range of the plurality of pumping wells covers the range of the pollution source area; the number of pumping wells is determined by the capture width of a single pumping well and the range of the pollution source area.

[0017] Optionally, the formula for calculating the capture width L of a single pumping well is:

[0018] ;

[0019] In the formula, Q is the pumping rate, M is the aquifer thickness, i is the hydraulic gradient of the aquifer under natural conditions, and k is the aquifer permeability coefficient.

[0020] Optional, also includes:

[0021] Multiple injection wells are installed in the downstream boundary area of ​​the pollution plume region through which groundwater flows, and the injection of water into the multiple injection wells is controlled until the water level in the pollution source area is maintained at a preset level.

[0022] Optionally, the radius of influence of a single injection well is 10 meters; the formula for calculating the preset water level u is:

[0023] ;

[0024] In the formula, The undisturbed water level in the pollution source area. The water head height when the radius of influence is 10m. M is the aquifer thickness, and k is the aquifer permeability coefficient.

[0025] Optionally, the preset duration The calculation formula is:

[0026] ;

[0027] The preset duration The calculation formula is:

[0028] ;

[0029] In the formula, k is the aquifer permeability coefficient, i is the hydraulic gradient when the aquifer is pumped, S is the maximum distance from the upstream boundary of the pollution source area to the pumping well, and c is the aquifer storage coefficient.

[0030] Optionally, the preset condition is that the concentration of pollutants in the extracted groundwater does not exceed a preset concentration value for a continuous hydrological year.

[0031] By adopting the above technical solution, pressure is repeatedly applied and unloaded within a short period of time in the pollution source area, and the pumping wells downstream of the pollution source area are activated, which increases the vertical movement of groundwater and artificially accelerates the scouring effect, which is stronger than the effect of natural groundwater flow. This accelerates the desorption of pollutants, increases the efficiency of pollutant extraction, shortens the pollution decay period, and keeps the concentration of pollutants in groundwater at a relatively low level, effectively improving the problems of tailing and rebound in groundwater pollution extraction and treatment. Attached Figure Description

[0032] Figure 1 This is a schematic flowchart of a groundwater pollution extraction and treatment method based on elastic water release, according to an embodiment of this application.

[0033] Figure 2 This is a schematic diagram showing the layout of the pressure points, pumping wells, and injection wells in the embodiments of this application. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0035] Figure 1 This is a schematic flowchart illustrating a groundwater contamination extraction and treatment method based on elastic water release, provided in this embodiment. Figure 1 As shown, the main process of this method is described below (steps S101 to S105):

[0036] Step S101: Set up multiple pressure points in the pollution source area and set up multiple pumping wells in the downstream boundary area where groundwater flows through the pollution source area;

[0037] Figure 2 This illustration shows one possible layout of the pressure application point and pumping well in this embodiment. For example... Figure 2 As shown, all pressure points are located within the pollution source area, and the total influence range of all pressure points must cover the entire pollution source area; all pumping wells are located within the downstream boundary area of ​​the groundwater flow direction in the pollution source area.

[0038] In this embodiment, the pressure application point is typically not a single point, but rather a surface. Applying a concentrated load to the ground in the pollution source area through the pressure application point generates additional stress exceeding the original soil stress level, creating a stress distribution effect on the surrounding soil. This effect range is defined as the influence range of the pressure application point. This influence range is a circle with the center point of the applied pressure as its center and the radius of influence as its radius.

[0039] The calculation of the radius of influence of a single pressure point is very complex because each point in space is different and requires three-dimensional integration. Therefore, the radius of influence of a single pressure point can be simplified and estimated based on the spherical transmission law of force.

[0040] Specifically, the radius of influence of a single pressure point is equal to the burial depth of the aquifer top plate, where the burial depth of the aquifer top plate refers to the thickness of the impermeable or weakly permeable layer (such as clay layer) overlying the aquifer, that is, the vertical distance from the ground to the top of the aquifer.

[0041] To facilitate implementation, the pressure applied at each pressure point is set to the same magnitude, which also ensures a more even stress distribution across the entire pollution source area. Once the radius of influence of each individual pressure point is determined, the area of ​​influence can be determined. Then, based on the size of the entire pollution source area, the minimum number of pressure points needed is determined so that the union of the influence areas of all pressure points completely covers the pollution source area. The location of each pressure point can be determined during the process of determining the number of pressure points. Of course, to completely cover the pollution source area, the capture ranges of adjacent pressure points will overlap.

[0042] In this embodiment, the downstream boundary area of ​​the groundwater flowing through the pollution source area refers to the area near the downstream boundary of the groundwater flow within the pollution source area. Therefore, the pumping wells can be all located outside the pollution source area, all located inside the pollution source area, or some located inside the pollution source area and others outside, as long as the total capture range of all pumping wells covers the entire pollution source and all pumping wells are located near the downstream boundary of the groundwater flow within the pollution source area. Placing the pumping wells in the downstream boundary area facilitates the collection of pollutants in the groundwater, the detection of pollutant concentrations, and, to some extent, the interception of a portion of the pollutants.

[0043] The capture range of a pumping well refers to the area that the well can influence and lower the surrounding groundwater level during pumping operations. This capture range determines the amount of groundwater the well can extract and the resulting groundwater flow. The capture range is a circle with the well itself as its center and the capture width as its radius.

[0044] The pumping capacity Q of a single pumping well can be calculated by multiplying the area of ​​a rectangle with a capture width L and an aquifer thickness M as its side length by the flow velocity V of the groundwater passing through that cross section. , where i is the hydraulic gradient of the aquifer under natural conditions, and k is the aquifer permeability coefficient.

[0045] Therefore, the formula for calculating the capture width L of a single pumping well can be derived as follows:

[0046] Formula (1);

[0047] It should be noted that the hydraulic gradient of an aquifer refers to the head loss per unit seepage path along the direction of water flow, and the magnitude of the hydraulic gradient directly affects the flow rate of groundwater. The aquifer permeability coefficient reflects the flow velocity of groundwater within the aquifer and can be obtained through laboratory tests and in-situ tests, such as pumping tests, pressure tests, and injection tests. In practical work, parameters are often inferred from field water level and flow data using mathematical models.

[0048] To facilitate implementation, the pumping capacity of each well is set to be the same, which also ensures a more even distribution of water level drop across the entire pollution source area. Once the capture width of each individual well is determined, the area of ​​the capture range can be determined. Then, based on the size of the entire pollution source area, the minimum number of wells needed can be determined so that the union of the capture ranges of all wells completely covers the pollution source area. The location of each well can be determined during the process of determining the number of wells. Of course, to completely cover the pollution source area, the capture ranges of adjacent wells will overlap.

[0049] Assuming there are N pumping wells, the capture width L of a single pumping well and the width A of the pollution source area perpendicular to the groundwater flow direction have the following relationship:

[0050] Formula (2);

[0051] To minimize the value of N in formula (2), the capture width L of a single pumping well is maximized by controlling the pumping rate Q. According to the Theis formula, the relationship between the output flow rate and the drawdown is:

[0052] Formula (3);

[0053] In formula (3), The depth of the well water level is Q, and the pumping rate is Q. k Where M is the formation permeability coefficient and M is the aquifer thickness. R is the radius of influence of the pumping operation, and R is the diameter of the pumping well.

[0054] Combining formulas (1) and (3), we can obtain:

[0055] Formula (4);

[0056] As can be seen from formula (4), to find the minimum number of pumping wells in the scheme, it can be obtained by maximizing L, which can be achieved by increasing the drawdown. This is achieved by simultaneously increasing the diameter R of the pumping well.

[0057] It should be noted that a pollution source refers to the location or area where pollutants initially enter the groundwater system. This can be a point source, such as factory discharge outlets, sewage treatment plant effluents, landfills, and mine drainage, or a non-point source, such as agricultural fertilization and urban rainwater runoff.

[0058] Step S102, within a preset duration The system applies pressure to the multiple pressure points repeatedly to raise the water level in the pollution source area and form a water mound.

[0059] In this embodiment, when an external force is applied to the soil through the pressure point, the pore water in the soil first bears this pressure, causing an increase in pore water pressure. Due to the redistribution of stress, some parts of the soil undergo elastic deformation, and the previously compressed pore water is released, forming local water mounds. This entire process is called elastic water release. When the external force is removed, the soil returns to its near-original state, and the pore water is redistributed accordingly.

[0060] It is important to note that a water mound is not directly equivalent to a bulge on the soil surface. Rather, it refers more to the localized accumulation of water in the soil due to elastic deformation of the soil skeleton and changes in pore water pressure, which causes the groundwater level to rise in the pollution source area.

[0061] Setting the preset duration to a relatively short time and repeatedly applying pressure to the soil within a short period can increase the vertical flow of groundwater and artificially accelerate the scouring effect, which is stronger than the effect of natural groundwater flow. This accelerates the desorption of pollutants in the vadose zone, increases the efficiency of pollutant extraction, and shortens the pollution decay period.

[0062] In some embodiments, the pressure applied at each pressure point can be determined based on the depth of the contaminated layer, which typically refers to the depth of the soil or rock layer containing the pollutants in the groundwater. Specifically, if the depth of the contaminated layer does not exceed 10 meters, the applied pressure at a single pressure point shall not be less than 20 tons; if the depth of the contaminated layer exceeds 10 meters, the applied pressure at a single pressure point shall not be less than 50 tons.

[0063] Since pressure needs to be applied and unloaded multiple times at the pressure point in a short period of time, a truck loaded with goods can be set as the load application object for ease of implementation. When pressure needs to be applied, the truck is driven to the center of the pressure point, and when pressure needs to be unloaded, the truck is driven away from the center of the pressure point and away from the pollution source area.

[0064] After pressure is applied, the transmission of pressure over a short distance can be considered instantaneous, but water flow requires a certain amount of time. In some embodiments, it is assumed that applying pressure is equivalent to the hydraulic gradient i increasing to 1, and the groundwater flow velocity V is... Let k be the aquifer permeability coefficient, a be the porosity, and a be a common value of 0.2, with a flow distance S of 0.25 m. Since... Therefore, the preset duration The calculation formula is:

[0065] Formula (5);

[0066] Preset duration The calculation formula is:

[0067] Formula (6);

[0068] In the formula, k is the aquifer permeability coefficient, i is the hydraulic gradient when the aquifer is pumped, S is the maximum distance from the upstream boundary of the pollution source area to the pumping well, and c is the aquifer storage coefficient, which describes the aquifer's ability to release or store water when the pressure head changes.

[0069] It should be noted that the hydraulic gradient during pumping... ,in, It is the water level at the upstream boundary of the pollution source area. B is the water level in the pumping well during pumping, and B is the distance from the upstream boundary of the pollution source area to the pumping well along the direction of groundwater flow. ,in, s is the water level in the pumping well under natural conditions, and s is the drawdown of the pumping well during pumping.

[0070] Optionally, if the calculated preset duration Less than 10 minutes, at this time the preset duration The duration can be set to 10 minutes, and the number of pressure applications can be set to 5.

[0071] Step S103, within the preset duration During the final pressurization, multiple pumping wells are controlled to start pumping water to lower the water level in the pollution source area.

[0072] In this embodiment, for a single pressurization point, the duration of all pressurization operations except for the last pressurization can be set to the same. The start time of the last pressurization is the start time of the pumping well.

[0073] Due to the aforementioned elastic water release phenomenon, the groundwater level in the pollution source area rises. At this time, the pumping well is opened, and after the pumping well starts pumping water, the water level in the pollution source area will gradually show a downward trend in order to eliminate the water mound and extract the pollutants.

[0074] Step S104: Adjust the pumping speed to lower the water level in the pollution source area to a preset depth below the undisturbed water level and maintain this level for a preset duration. Then, control multiple pumping wells to stop pumping water and unload the pressure at the pressure application point;

[0075] In this embodiment, the undisturbed water level, also known as the original water level or natural water level, refers to the stable water level that groundwater naturally reaches without being disturbed by human activities such as extraction or injection. The undisturbed water level reflects the equilibrium state of the groundwater system under natural conditions. That is to say, before the extraction and treatment method described in this embodiment is carried out, the groundwater level in the pollution source area is the undisturbed water level.

[0076] By applying pressure to the soil at the pressure point while simultaneously controlling the pumping wells, the groundwater level can be restored to an undisturbed level. Furthermore, to extract a sufficiently large volume of contaminated water, pumping continues after the groundwater level has returned to the undisturbed level until it drops to a predetermined depth below the undisturbed level. This predetermined depth is typically set to be greater than 15 meters, and the water level must be maintained stably for a certain period before pumping is stopped and the external force applied at the pressure point is unloaded. This design allows for the rapid extraction of large quantities of contaminated water.

[0077] It should be noted that the water level in the pollution source area can be equivalent to the water level monitored at the pumping well, i.e., the water level of the pumping well.

[0078] Step S105: After unloading the pressure at the pressure application point, a water level funnel forms within the pollution source area. When the water level in the pollution source area returns to the undisturbed water level, the process is repeated for a preset duration. The process involves applying pressure to multiple pressure points repeatedly to raise the water level in the pollution source area and form a water mound, until the concentration of pollutants in the extracted groundwater meets the preset conditions.

[0079] In this embodiment, after the pressure at the pressure application point is released, although the water mound disappears, a local water level trough, or water level funnel, will form. At this time, the water level in the pollution source area will be lower than the undisturbed water level. It is necessary to wait for upstream and lateral groundwater to replenish the water level so that it can return to the undisturbed water level.

[0080] In some embodiments, groundwater is extracted in real time to measure the concentration of pollutants in the groundwater. If the concentration of pollutants in the groundwater does not exceed the preset concentration value for a hydrological year, it is not necessary to repeat steps S101 to S104. Otherwise, steps S101 to S104 need to be repeated to perform the process of pressurizing the pressurization point and pumping water from the pumping well.

[0081] Furthermore, if the groundwater pollutant concentration does not exceed the preset concentration value for three consecutive hydrological years, the entire groundwater pollution extraction and treatment process can be stopped, and monitoring of the groundwater pollutant concentration in the area can be discontinued. The preset concentration value can be set with reference to the Class III water limits in the "Groundwater Environmental Quality Standard".

[0082] Furthermore, pollutants spreading from pollution sources can form an area in groundwater. This area migrates and spreads with the flow of groundwater, forming a feather-like distribution known as a pollution plume. The morphology, size, and diffusion rate of the pollution plume are influenced by various factors, including the flow rate of groundwater, the chemical properties of the pollutants, and the geological structure of the aquifer.

[0083] To control the local flow field, reduce the local hydraulic gradient, and limit the downstream diffusion of pollutants, multiple injection wells can be installed in the downstream boundary area of ​​the pollution plume region through which groundwater flows. The injection of water from these wells can be controlled until the water level in the pollution source area is maintained at a preset level. This injection process is independent of and does not affect the aforementioned pressurization and pumping processes.

[0084] In this embodiment, the downstream boundary region through which groundwater flows in the contamination plume area refers to the area near the downstream boundary of the contamination plume area. Therefore, the injection wells can all be located outside the contamination plume area, all inside the contamination plume area, or partly inside the contamination plume area and partly outside the contamination plume area (e.g., Figure 2 As shown in the figure, it is acceptable as long as the sum of the influence range of all injection wells covers the entire pollution plume area and all injection wells are located near the downstream boundary of the groundwater flow direction in the pollution plume area.

[0085] The influence range of a water injection well refers to the area that the well can influence and raise the surrounding groundwater level during water injection operations. This influence range determines the amount of water that the well can inject and the resulting groundwater flow. The influence range is a circle with the well itself as its center, and the radius of this circle is the radius of influence of the water injection well.

[0086] To facilitate implementation, the injection volume of each well is set to be the same, which also ensures a more even distribution of water level rise across the entire plume area. Once the influence radius of each individual well is determined, the size of the affected area can be determined. Then, based on the size of the entire plume area, the minimum number of wells needed can be determined so that the union of the influence areas of all wells completely covers the entire plume area. The location of each well can be determined during the process of determining the number of wells. Of course, to completely cover the plume area, the influence areas of adjacent wells will overlap.

[0087] By placing the injection well in the downstream boundary area, the water level rises, which dilutes and intercepts the flow, reducing the migration of pollutants downstream. At the same time, maintaining the water level at the injection well also accelerates the recovery of the water level funnel.

[0088] Setting the well spacing between injection wells to 10m, and ensuring that the influence range of the water head rise is also 10m, allows the water head rise ranges generated by the injection wells to connect seamlessly, creating a continuous hydraulic barrier effect. The formula for calculating the influence radius R of a single injection well is a commonly used empirical formula. ,in, This refers to the water head height above the undisturbed water level.

[0089] Optionally, the radius of influence R of a single injection well is set to 10 meters; the formula for calculating the preset water level u is:

[0090] Formula (7);

[0091] In formula (7), The undisturbed water level in the pollution source area. The water head height when the radius of influence is 10m. M is the aquifer thickness, and k is the aquifer permeability coefficient.

[0092] Hydraulic head describes the potential energy state of water underground or on the Earth's surface. It is a unit of energy, usually expressed in meters or feet. Hydraulic head can be considered as the energy required for water to rise from its current position to a reference horizontal plane, which consists of both the water's gravitational potential energy and pressure potential energy.

[0093] Additionally, it should be understood that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0094] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for treating groundwater pollution based on elastic water release, characterized in that, include: Multiple pressure points are set up in the pollution source area, and multiple pumping wells are set up in the downstream boundary area where groundwater flows through the pollution source area; Within a preset time period T1, multiple pressure points are applied to cause the water level in the pollution source area to rise and form a water mound. During the final pressurization within the preset time T1, the multiple pumping wells are controlled to start pumping water to lower the water level in the pollution source area. Adjust the pumping speed to lower the water level in the pollution source area to a preset depth below the undisturbed water level and maintain it for a preset time T2, then control the multiple pumping wells to stop pumping and unload the pressure at the pressure application point. After the pressure at the pressure point is released, a water level funnel is formed in the pollution source area. When the water level in the pollution source area returns to the undisturbed water level, the process of applying pressure to the multiple pressure points multiple times within a preset time T1 is repeated to raise the water level in the pollution source area and form a water mound until the pollutant concentration of the extracted groundwater meets the preset conditions. The influence range of the multiple pressure points covers the area of ​​the pollution source region; the number of pressure points is determined by the influence radius of a single pressure point and the range of the pollution source region. The radius of influence of a single pressure point is equal to the burial depth of the top plate of the aquifer. The formula for calculating the preset duration T1 is as follows: The formula for calculating the preset duration T2 is as follows: In the formula, k is the aquifer permeability coefficient, i is the hydraulic gradient when the aquifer is pumped, S is the maximum distance from the upstream boundary of the pollution source area to the pumping well, and c is the aquifer storage coefficient. The preset condition is that the concentration of pollutants in the extracted groundwater does not exceed a preset concentration value for a continuous hydrological year.

2. The method according to claim 1, characterized in that, If the depth of the contaminated layer does not exceed 10 meters, the pressure applied at a single pressure point shall not be less than 20 tons; if the depth of the contaminated layer exceeds 10 meters, the pressure applied at a single pressure point shall not be less than 50 tons.

3. The method according to claim 1, characterized in that, The capture range of the plurality of pumping wells covers the area of ​​the pollution source region; the number of pumping wells is determined by the capture width of a single pumping well and the extent of the pollution source region.

4. The method according to claim 3, characterized in that, The formula for calculating the capture width L of a single pumping well is: In the formula, Q is the pumping rate, M is the aquifer thickness, i is the hydraulic gradient of the aquifer under natural conditions, and k is the aquifer permeability coefficient.

5. The method according to claim 1, characterized in that, Also includes: Multiple injection wells are installed in the downstream boundary area of ​​the pollution plume region through which groundwater flows, and the injection of water into the multiple injection wells is controlled until the water level in the pollution source area is maintained at a preset level.

6. The method according to claim 5, characterized in that, The radius of influence of a single injection well is 10 meters; The formula for calculating the preset water level u is: u = u1 + u2; In the formula, u1 is the undisturbed water level in the pollution source area, and u2 is the water head height with an influence radius of 10m. M is the aquifer thickness, and k is the aquifer permeability coefficient.

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