Soil groundwater circulation remediation well device and remediation method

Abstract

The application discloses a soil and underground water circulation remediation well device and a remediation method. The device comprises a circulation well which is arranged at soil to be remediated and sequentially comprises an upper screen pipe section, a closed pipe section and a lower screen pipe section from top to bottom; the upper screen pipe section and the lower screen pipe section serve as the well body inlet and outlet of underground water; a flexible air bag unit is immersed in the underground water in the well body, the upper and lower ends of the air bag are made of hard material and the side wall surface is made of flexible material; a pipeline is sealedly penetrated between the upper and lower ends, and the pipeline is used for accommodating an inflation pipeline, a gas extraction pipeline and a gas pressure monitoring line; the underground water circulation in the soil and the well body is completed through intermittent inflation and gas extraction of the air bag. The air bag arranged in the well body and selective inflation and gas extraction of the air bag at different positions are used, without using a submersible pump and a water isolation section and other facilities in the pump lifting method, and without converting the pollutants into a gas phase and then extracting and remediation, so that the underground in-situ remediation of the pollutants is realized under the premise of effectively realizing the underground water circulation.

Description

Technical Field

[0001] This invention relates to the field of soil and groundwater remediation technology, and in particular to a soil and groundwater circulation remediation well device and remediation method. Background Technology

[0002] With the development of industrialization, urbanization, and agricultural modernization, the chemical industry, mining, metal smelting, use of pesticides and fertilizers, and discharge of domestic wastewater are constantly causing environmental safety problems related to soil and groundwater. The discharge of these three types of waste, as well as accidental leaks in storage devices and transportation pipelines, pose serious threats to soil and groundwater. For example, mine wastewater and industrial wastewater from chemical plants can cause pollutants to accumulate in soil and groundwater. In agriculture, the extensive use of fertilizers and pesticides is increasingly causing soil and groundwater pollution problems. Urban residential areas discharge large amounts of domestic sewage and solid waste daily, including organic matter containing nutrients for microorganisms such as carbohydrates, nitrogen, phosphorus, and sulfur, as well as various pathogenic microorganisms. When these pollutants enter water bodies, they cause a large consumption of dissolved oxygen, easily producing foul-smelling substances under the action of anaerobic bacteria, and simultaneously causing the proliferation and spread of pathogens and viruses. Therefore, soil and groundwater remediation requires long-term implementation.

[0003] Soil and groundwater remediation can be achieved using chemical agents, which require injecting chemicals into the soil layer. To achieve rapid action of the injected agents, existing technologies utilize groundwater circulation well remediation technology. For example, Chinese patent application CN115818866A provides a groundwater circulation well remediation system, including a circulation well unit, a chemical dosing device, a gas input device, and a waste gas extraction and treatment device. The circulation well unit has an upper screen pipe section and a lower screen pipe section spaced apart from it. A main well pipe is located between the upper and lower screen pipe sections, extending downwards from the ground surface. Water-resistant sections are located at the lower end of the upper screen pipe section and at the upper and lower ends of the lower screen pipe section. This design allows the groundwater within the main well pipe to form a vertical circulation flow with external groundwater, thereby improving the mixing effect between the chemical oxidizing agent in the chemical dosing device and the groundwater, enhancing the disturbance to the aquifer medium, and promoting the desorption of organic pollutants. However, this type of solution requires the construction of specific supporting groundwater circulation wells, and the installation of extraction pumps, ultrasonic vibration devices, water-proof sections, etc. inside the wells. The well pipe structure is very complex, the construction process requirements are high, and a gas extraction device needs to be installed on the ground. The economic efficiency of repairing the entire system is poor, which is not conducive to the implementation and promotion of the technology.

[0004] For example, Chinese patent application CN116514210A discloses a packing-enhanced circulation well system based on funnel-shaped internal components, belonging to the field of groundwater remediation technology. In this solution, the inner well pipe is equipped with a submersible pump and funnel-shaped internal components from bottom to top. By adding funnel-shaped internal components to replace the traditional pipe sealing system, hydraulic circulation can be enhanced and construction difficulty reduced. However, this type of solution still requires facilities such as submersible pumps, and there is a possibility of short-circuiting of water flow within the well pipe, so circulation efficiency cannot be effectively guaranteed.

[0005] Therefore, there is an urgent need for a soil groundwater circulation remediation well device and remediation method that can ensure circulation efficiency while avoiding the use of complex facilities such as submersible pumps and water-proof sections in existing technologies, and also avoid the problem of "water flow short circuit" in the well.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a soil groundwater circulation remediation well device and remediation method. By installing airbags in the well body and selectively inflating and deflating airbags at different locations, it eliminates the need for facilities such as submersible pumps and water-proof sections in pump extraction methods, and also eliminates the need to convert pollutants into gaseous phases for extraction and remediation. Under the premise of effectively realizing groundwater circulation, it achieves in-situ underground remediation of pollutants.

[0008] Another objective of this invention is to provide a soil groundwater circulation remediation well device and remediation method, which can also avoid the problem of "water flow short circuit" in the well by selectively inflating and deflating airbags at different locations.

[0009] To achieve the above objectives, according to a first aspect of the present invention, a soil groundwater circulation remediation well device is provided, comprising: a circulation well, which is located at the soil to be remediated and is provided with an upper screen pipe section, a closed pipe section, and a lower screen pipe section from top to bottom; the upper screen pipe section and the lower screen pipe section serve as the well body inlet and outlet of groundwater; a flexible airbag unit, which is immersed in the groundwater in the well body, the upper and lower ends of the airbag are made of rigid material and the side walls are made of flexible material; a pipe is sealed and penetrated between the upper and lower ends, the pipe being used to accommodate an inflation pipe, an exhaust pipe, and a pressure monitoring line; the intermittent inflation and exhaust of the airbag completes the circulation of groundwater in the soil and in the well body.

[0010] Furthermore, in the above technical solution, the flexible airbag unit can be a single structure or multiple single structures connected in series through pipes.

[0011] Furthermore, in the above technical solution, the flexible airbag unit can be a single structure containing multiple sub-airbags, with adjacent sub-airbags sharing the end face of a rigid material.

[0012] Furthermore, in the above technical solution, after the flexible airbag unit is inflated, the side wall of the airbag can tightly adhere to and hold the well wall.

[0013] Furthermore, in the above technical solution, an air pump and an air valve can be sequentially installed upstream of the air inflation pipeline; an air extraction pump and an air extraction valve can be sequentially installed upstream of the air extraction pipeline.

[0014] Furthermore, in the above technical solution, the air pressure monitoring line may be equipped with a pressure sensor located inside the airbag and a pressure gauge located on the ground.

[0015] Furthermore, in the above technical solution, the device of the present invention further includes: a drug injection pipeline, the port of which can be set at the height of the upper screen tube section and located outside the upper screen tube section; the upstream of the drug injection pipeline can be sequentially connected to a drug tank, a drug injection pump and a drug injection pressure gauge.

[0016] Furthermore, in the above technical solution, the outer side of the upper screen tube section can be filled with a packing medium, the outer side of the closed tube section can be filled with bentonite, and the outer side of the lower screen tube section can be filled with quartz sand. The packing medium can be activated carbon or an iron-based supported catalyst.

[0017] Furthermore, in the above technical solution, the agent can be an oxidant, and the repair process forms a catalytic oxidation system.

[0018] To achieve the above objectives, according to a second aspect of the present invention, the present invention provides a method for soil groundwater circulation remediation, using the apparatus of any of the foregoing claims, comprising the following steps: A. Placing an uninflated flexible airbag unit into a well body having an upper screen pipe section, a closed pipe section, and a lower screen pipe section, and injecting a remediation agent into the soil at a corresponding position on the outside of the upper screen pipe section; B. Inflating the airbag through an inflation pipeline, so that the sidewall of the inflated airbag tightly adheres to and holds the well wall, the airbag expands and reaches a preset pressure, the liquid level in the well rises, and the water in the upper part of the airbag is discharged from the upper screen pipe section into the soil under positive pressure; C. After the pressure inside and outside the well body reaches equilibrium, the gas in the airbag is evacuated through an air extraction pipeline, and the water enters the well body from the soil in the lower screen pipe section under negative pressure, thus intermittently inflating and evacuating to complete the groundwater circulation in the soil and the well body.

[0019] Furthermore, in the above technical solution, when the flexible airbag unit's airbag body adopts multiple serially connected single-unit structures or a single-unit structure containing multiple sub-airbags, the inflation process in step B is performed sequentially from bottom to top. While the uppermost airbag or sub-airbag is inflated, the lowermost airbag or sub-airbag is deflated.

[0020] Furthermore, in the above technical solution, when the flexible airbag unit's airbag body adopts multiple serially connected single-unit structures or a single-unit structure containing multiple sub-airbags, the air extraction process in step C is performed sequentially from bottom to top. While the uppermost airbag or sub-airbag is being deflated, the lowermost airbag or sub-airbag is being inflated.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) The airbag in this invention uses a flexible material for its sidewalls and a rigid material for its top and bottom ends. A cylindrical pipe runs through the middle of the airbag, which can be used for inflation lines, extraction lines, and pressure monitoring lines. The flexible airbag is cylindrical when inflated and gradually expands as the internal pressure increases, tightly adhering to and holding the borehole wall, creating positive pressure within the wellbore. In extraction mode, negative pressure is created within the wellbore. This intermittent positive and negative pressure provides the power for groundwater circulation.

[0023] 2) When the contamination location is shallow and the area to be repaired is small, the flexible airbag unit used in this invention can be a single airbag structure; when the longitudinal range of contamination is large, the circulation well needs to be dug deeper and the longitudinal repair area is large, multiple single airbag structures can be connected in series or a single airbag with multiple sub-airbags can be used. This not only avoids the use of excessively long airbags and reduces customization difficulty, but also reduces the cost of use and makes it more adaptable to the contamination situation on site.

[0024] 3) When multiple single airbags are connected in series or a single airbag has multiple sub-airbags, the present invention can obtain intermittent positive and / or negative pressure in the well body by controlling each single airbag or each sub-airbag in sequence. This can not only automatically control and provide effective power for groundwater circulation, but also avoid the problem of "water flow short circuit".

[0025] 4) This invention eliminates the need to construct complex underground water circulation wells. The facilities inside the wells are easy to construct and operate, resulting in low cost, short construction time, high efficiency and convenience, and greatly reducing the amount of engineering work.

[0026] 5) Compared with the existing "pump extraction method", this invention does not require the use of a submersible pump, thus avoiding the high energy consumption caused by the large inner diameter of the circulation well; compared with the existing "in-well aeration extraction method", it does not produce a large amount of polluting gas, thereby reducing the airtightness requirements of the well from the ground. The pollutant remediation of this invention can be completed in situ underground.

[0027] 6) This invention, by adjusting the inflation and deflation sequence of the airbag, is applicable not only to forward flow circulation wells but also to reverse flow circulation wells;

[0028] 7) The flexible airbag unit of the present invention can also effectively deal with the problem of screen tube blockage. Through the rapid inflation and deflation of the screen tube section airbag or sub-airbag, positive pressure and negative pressure are generated intermittently, which can effectively flush away the blockage at the screen tube.

[0029] 8) The flexible airbag unit of the present invention can be recycled and reused after the repair task is completed.

[0030] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the connection of the soil and groundwater circulation remediation well device of the present invention (the flexible airbag unit includes a single structure of three sub-airbags; the dashed arrows in the figure indicate the circulation direction of the water body).

[0032] Figure 2 This is a schematic diagram of the flexible airbag unit of the present invention using a single airbag structure.

[0033] Figure 3 This is a schematic diagram of the single-unit structure of the flexible airbag unit of the present invention, which uses three sub-airbags.

[0034] Figure 4 yes Figure 3 A schematic diagram of the structure of the three sub-airbags after deflation.

[0035] Explanation of key figure labels:

[0036] 1-Flexible airbag unit, 100-End face, 101-Side wall, 1A-First sub-airbag, 1B-Second sub-airbag, 1C-Third sub-airbag; 2-Well body, 21-Upper screen pipe section, 22-Sealed pipe section, 23-Lower screen pipe section, 3-Filling layer, 31-Filling medium, 32-Bentonite, 33-Quartz sand, 4-Hollow pipe, 41-Inflation pipe, 410-Inflation port, 42-Pressure monitoring line, 420-Pressure sensor, 43-Extraction pipe, 430-Extraction port, 5-Agent injection pipe, 6-Agent tank, 7-Agent injection pump, 8-Agent injection pressure gauge, 9-Extraction pump, 10-Extraction valve, 11-Pressure gauge, 12-Inflation pump, 13-Inflation valve. Detailed Implementation

[0037] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0038] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0039] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0040] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0041] Example 1

[0042] like Figures 1 to 4 As shown, this embodiment provides a soil groundwater circulation remediation well device, which includes at least a circulation well and a flexible airbag unit 1. The circulation well is located at the soil to be remediated and, from top to bottom, consists of an upper screen pipe section 21, a closed section 22, and a lower screen pipe section 23. The upper screen pipe section 21 and the lower screen pipe section 23 serve as the inlet and outlet of the well body 2 for groundwater. The flexible airbag unit 1 is submerged in the groundwater within the well body 2. The end faces 100 at both ends of the airbag are made of rigid material, while the sidewalls 101 are made of flexible material (see reference). Figure 2 A hollow pipe 4 is sealed between the upper and lower ends, and the pipe 4 is used to accommodate the inflation pipe 41, the extraction pipe 43, and the air pressure monitoring line 42. In this embodiment, the circulation of groundwater in the soil and well body 2 can be achieved through the intermittent inflation and extraction of the airbag. Preferably, but not limitingly, the flexible airbag unit can be a single structure (see reference). Figure 2 It can also be a single-unit structure connected in series via pipe 4, or a single-unit structure containing multiple sub-airbags (see reference). Figure 3 When multiple sub-airbag structures are used, adjacent sub-airbags share the end face 100 of the rigid material. Furthermore, after the flexible airbag unit 1 is inflated, the side wall surface 101 of the airbag can tightly adhere to and hold the well wall.

[0043] This embodiment utilizes flexible airbag units, eliminating the need for complex groundwater circulation wells. The well's internal facilities are highly operable and easy to construct. When the circulation well is shallow and the longitudinal repair area is small, a single airbag can be used, with intermittent inflation and deflation of the airbag to achieve groundwater circulation within the well and in the soil. When the circulation well is deep and the longitudinal repair area is large, multiple single-unit airbag structures can be used in series, or a single structure containing multiple sub-airbags can be employed. By controlling the inflation and deflation sequence of multiple single airbags or multiple sub-airbags, positive and negative pressures are intermittently generated within the well, thereby achieving groundwater circulation within the well and in the soil, thus improving repair efficiency. Applying the flexible airbag unit of this embodiment to circulation wells proposes a novel inventive concept. Compared to the "pump extraction method," it eliminates the need for submersible pumps and water-tight sections. Compared to the "in-well aeration extraction method," it does not generate a large amount of polluting gas, and pollutants can be repaired in situ underground. Furthermore, it effectively avoids the problem of "waterway short-circuiting" within the well.

[0044] Further as Figure 1 As shown, the upper screen section 21 and the lower screen section 23 are non-sealed pipes with screen holes or slits to allow water to pass through, preferably slits with a width of 1mm-3mm. The sealed section 22 is watertight. A filling layer 3 is provided on the outside of the well section. Preferably, but not limitingly, the upper screen section 21 is filled with a filler medium 31, which can be activated carbon or an iron-based supported catalyst, as needed. The sealed section 22 can be filled with bentonite 32, and the lower screen section 23 can be filled with quartz sand 33.

[0045] Further as Figure 2 , 3 As shown, the sidewall 101 of the single airbag in this embodiment is made of a flexible material, which has the characteristics of high strength and high flexibility. It is preferably pressure-resistant and corrosion-resistant rubber, but other materials with equivalent effects can also be used. A hollow pipe 4 is provided in the middle of the airbag to accommodate the inflation pipe 41, the deflation pipe 43, the air pressure monitoring line 42, etc. The pipe 4 passes through the airbag and is sealed to it. The top and bottom of the airbag (i.e., Figure 2 The rigid connection between the end face 100 and the sub-airbag (reference) Figure 3 The material is preferably corrosion-resistant aluminum. The airbag is an inflatable cylinder when inflated. As the internal pressure of the airbag increases, the sidewall 101 gradually expands, allowing the airbag to tightly adhere to and hold the well wall. Multiple Figure 2 The individual airbags shown can be used in series. When the circulation well is deep and the longitudinal repair area is large, if a single airbag is used for repair, the airbag needs to be long enough. In this application scenario, multiple airbags can be placed in series inside the well. Figure 2The airbags shown avoid the use of excessively long airbags, reducing customization complexity and lowering operating costs. Each airbag can follow a pre-defined inflation and deflation sequence. When airbags are used in series, they can be multiple single-unit airbags or a single-unit airbag containing multiple sub-airbags (see reference). Figure 3 ). Figure 3 The diagram shows three sub-airbag structures, namely, the first sub-airbag 1A, the second sub-airbag 1B, and the third sub-airbag 1C arranged sequentially from top to bottom, with adjacent sub-airbags sharing the end face 100 of a rigid material.

[0046] Further as Figure 1 As shown, an air pump 12 and an air valve 13 are sequentially installed upstream of the inflation line 41, and an inflation port 410 is provided at the end of the inflation line 41 inside the airbag (see reference). Figure 2 , Figure 3 The upstream of the suction pipe 43 is equipped with a suction pump 9 and a suction valve 10, and the end of the suction pipe 43 located inside the airbag is equipped with a suction port 430 (see reference). Figure 2 , Figure 3 The air pressure monitoring line 42 is equipped with a pressure sensor 420 located inside the airbag and a pressure gauge 11 located on the ground. In this embodiment, both the inflation and deflation processes can be fully automatically controlled.

[0047] Further as Figure 1 As shown, the device in this embodiment also includes a reagent injection pipeline 5. The injection port of the reagent injection pipeline 5 is located at the height of the upper screen tube section 21 and outside the upper screen tube section. The upstream of the reagent injection pipeline 5 is sequentially connected to a reagent tank 6, a reagent injection pump 7, and a reagent injection pressure gauge 8. Depending on the type of pollutant and the remediation requirements, oxidants such as sodium persulfate can be used, and the remediation process forms a catalytic oxidation system.

[0048] Example 2

[0049] This embodiment provides a method for soil groundwater circulation remediation, using the apparatus described in Embodiment 1 above, and includes the following steps (see reference). Figure 1 ):

[0050] Step S101, insert the uninflated flexible airbag unit (reference) Figure 4 A single airbag structure containing three sub-airbags is placed into a well body 2 having an upper screen pipe section 21, a closed pipe section 22 and a lower screen pipe section 23, and the remediation agent is injected into the soil at the corresponding position outside the upper screen pipe section 21.

[0051] In step S102, air is inflated into the airbag through the air inflator 41, so that the side wall of the inflated airbag is tightly attached to the well wall and hugs it. The airbag expands and reaches the preset pressure, the liquid level in the well rises, and the water in the upper part of the airbag is discharged from the upper screen pipe section 21 into the soil under positive pressure.

[0052] In step S103, after the pressure inside and outside the well body reaches equilibrium, the gas in the airbag is evacuated through the air extraction pipe 43. Under negative pressure, water enters the well body 2 from the soil in the lower screen pipe section 23. This intermittent inflation and deflation completes the circulation of groundwater in the soil and the well body 2.

[0053] Through the above steps, Embodiment 2 of this method can achieve the same technical effect as Embodiment 1. Further, when the airbag body of the flexible airbag unit 1 adopts multiple serially connected single-unit structures or a single-unit structure containing multiple sub-airbags, the inflation process in step S102 is performed sequentially from bottom to top. During this process, while the uppermost airbag or sub-airbag is inflated, the lowermost airbag or sub-airbag is deflated; when the airbag body of the flexible airbag unit 1 adopts multiple serially connected single-unit structures or a single-unit structure containing multiple sub-airbags, the deflation process in step S103 is performed sequentially from bottom to top. During this process, while the uppermost airbag or sub-airbag is deflated, the lowermost airbag or sub-airbag is inflated.

[0054] The following is based on Figure 3 Taking a flexible airbag unit 1 containing three sub-airbags as an example, the airbag inflation and deflation sequence is explained in detail:

[0055] pass Figure 1 After constructing the groundwater circulation well of the present invention as shown, Figure 4The uninflated airbag shown is placed in well body 2. The air pump 12 first inflates the third sub-airbag 1C through the air inflating pipe 41. The air inflating pipe of the third sub-airbag 1C is opened, and the third sub-airbag 1C gradually expands, displacing the groundwater in the well surrounding it. The water level in the well rises slowly with the expansion of the airbag and flows out from the upper screen pipe section 21. After the third sub-airbag 1C reaches the preset pressure, the air inflating pipe of the third sub-airbag 1C is closed. The air inflating pipe of the second sub-airbag 1B is opened, and the air pump 12 inflates the second sub-airbag 1B through the air inflating pipe 41. The second sub-airbag 1B gradually expands, displacing the groundwater in the well surrounding it. The water level in the well rises slowly with the expansion of the airbag and flows out from the upper screen pipe section 21. After the second sub-airbag 1B reaches the preset pressure, the air inflating pipe of the second sub-airbag 1B is closed. The air inflating pipe of the first sub-airbag 1A is opened, and the air pump 12 inflates the first sub-airbag 1A through the air inflating pipe 41... Inflation of the first sub-airbag 1A causes it to gradually expand, displacing the surrounding groundwater in the well. The water level in the well rises slowly as the airbag expands, flowing out from the upper screen pipe section 21. Once the first sub-airbag A reaches the preset pressure, its inflation line is closed. It should be noted that while the inflation line of the first sub-airbag 1A is open to inflate it (i.e., the uppermost sub-airbag), the extraction line 41 of the third sub-airbag 1C (i.e., the lowermost sub-airbag) is opened. The third sub-airbag 1C gradually contracts, creating negative pressure nearby, and groundwater enters the well body 2 from the lower screen pipe section 23. After the inflation line of the first sub-airbag 1A is closed, the extraction line of the second sub-airbag 1B is opened. The second sub-airbag 1B gradually contracts, creating negative pressure nearby, and groundwater enters the well body 2 from the lower screen pipe section 23. At this point, the first sub-airbag 1A is inflated, while the second sub-airbag 1B and the third sub-airbag 1C are in contracted. This is the initial state of the cycle.

[0056] Next, the inflation line of the third sub-airbag 1C is opened, and the third sub-airbag 1C gradually inflates, displacing the surrounding groundwater in the well. Simultaneously, the suction line of the first sub-airbag 1A is opened, and the first sub-airbag 1A gradually contracts, creating a negative pressure nearby. This provides space for the groundwater displaced by the expansion of the third sub-airbag 1C, drawing groundwater from the lower part of the well into this space. This process continues until the second sub-airbag 1B inflates. After this, the first sub-airbag 1A inflates, and simultaneously, the third sub-airbag 1C contracts, creating a negative pressure nearby, drawing groundwater from the lower screen pipe section 23 into this space. Then, the second sub-airbag 1B contracts, creating a negative pressure nearby, drawing groundwater from the lower screen pipe section 23 into this space. At this point, the first sub-airbag 1A is inflated, while the second sub-airbag 1B and the third sub-airbag 1C are contracted; this is the end of the cycle.

[0057] Repeat the above cycle until the repair work is completed. Throughout the entire repair process, the inflation and deflation of the airbags are automatic. Groundwater enters the circulation well from the lower screen section and flows out from the upper screen section, forming a three-dimensional circulation flow around the well. Because the water in the soil strata is in an open state, while the upper and lower ends of the well are closed, the positive and negative pressures created during the inflation and deflation of the airbags primarily have an effect within the well. By sequentially inflating and deflation, the circulating water will not experience "backflow," thus effectively avoiding the problem of "water flow short-circuiting." The inflation and deflation of the airbags should follow the above-mentioned sequence; otherwise, water near the airbags may not be able to drain, and in this case, the airbags may rupture.

[0058] The technical effects of the present invention can be verified by conducting simulation experiments in two specific examples in the test chamber:

[0059] Example 1:

[0060] Inside a 1.5m × 1m × 1.5m (length × width × height) groundwater pollution simulation test chamber, a 10cm thick clay layer was evenly laid at the bottom, followed by a 1.2m thick layer of silt with a horizontal permeability coefficient of approximately 0.4m / d, and a 0.2m thick layer of topsoil. The water level inside the test chamber was controlled at 1.2m above the test site. A groundwater circulation well with an airbag assembly was installed in the middle of the test chamber, with a well diameter of 63mm. Activated carbon was used as the external packing material for the upper screen section, and sodium persulfate was used as the oxidant at a concentration of 100g / L, with an injection flow rate of 10mL / h. The airbag operated according to the aforementioned automatic control process. Driven by the hydraulic circulation, it significantly enhanced the mass transfer efficiency of the oxidizing active substances, effectively expanding the reagent delivery range.

[0061] Toluene was injected into a simulated test chamber at a depth of 0.6 m. The toluene concentration at 0.6 m was measured to be 1542 ug / L. After 48 hours, the toluene concentration at 1 m was measured to be 1361 ug / L. The test was then started. After 24 hours, samples were taken for testing. The toluene concentration was 728 ug / L. After 48 hours, the toluene concentration was 624 ug / L. After 72 hours, the toluene concentration was 591 ug / L, achieving a pollutant removal rate of 56.6%.

[0062] Example 2:

[0063] Inside a 1.5m × 1m × 1.5m (length × width × height) groundwater pollution simulation test chamber, a 10cm thick clay layer was evenly laid at the bottom, followed by a 1.2m thick layer of silt with a horizontal permeability coefficient of approximately 0.4m / d, and a 0.2m thick layer of topsoil. The water level inside the test chamber was controlled at 1.2m above the test site. A groundwater circulation well with a flexible airbag was installed in the middle of the test chamber, with a well diameter of 63mm. An iron-based supported catalyst was used as the external packing material for the upper screen section, and sodium persulfate was used as the oxidant to form a catalytic oxidation system. The sodium persulfate concentration was 60g / L, and the injection flow rate was 10mL / h. The airbag operated according to the aforementioned automatic control process.

[0064] Toluene was injected into a simulated test chamber at a depth of 0.6 m. The toluene concentration at 0.6 m was measured to be 1857 ug / L. After 48 hours, the toluene concentration at 1 m was measured to be 1584 ug / L. The test was then initiated. After 24 hours, samples were taken for testing. The toluene concentration was 546 ug / L. After 48 hours, the concentration was 459 ug / L. After 72 hours, the concentration was 387 ug / L. The pollutant removal rate reached 75.6%.

[0065] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A soil groundwater circulation and remediation well device, characterized in that, include: A circulating well is constructed at the site of soil to be remediated and consists of an upper screen pipe section, a closed pipe section, and a lower screen pipe section from top to bottom; the upper and lower screen pipe sections serve as the well inlet and outlet for groundwater. A flexible airbag unit is submerged in groundwater within the well. The upper and lower ends of the airbag are made of rigid material, while the sidewalls are made of flexible material. A sealed pipe runs through the upper and lower ends, housing inflation and deflation lines, as well as pressure monitoring circuitry. Intermittent inflation and deflation of the airbag facilitates the circulation of groundwater in the soil and within the well. The flexible airbag unit can be a single structure connected in series via the pipe or a single structure containing multiple sub-airbags. When the flexible airbag unit is a single structure containing multiple sub-airbags, adjacent sub-airbags share the end faces of the rigid material. The inflation process proceeds sequentially from bottom to top. While the uppermost airbag or sub-airbag is inflated, the lowermost airbag or sub-airbag is deflated. The deflating process also proceeds sequentially from bottom to top. While the uppermost airbag or sub-airbag is deflated, the lowermost airbag or sub-airbag is inflated.

2. The soil and groundwater circulation remediation well device according to claim 1, characterized in that, After the flexible airbag unit is inflated, the sidewall of the airbag fits tightly against the well wall and holds it in place.

3. The soil and groundwater circulation remediation well device according to claim 1, characterized in that, An air pump and an air valve are sequentially installed upstream of the air inflation pipeline; an air extraction pump and an air extraction valve are sequentially installed upstream of the air extraction pipeline.

4. The soil and groundwater circulation remediation well device according to claim 1, characterized in that, The air pressure monitoring line is equipped with a pressure sensor located inside the airbag and a pressure gauge located on the ground.

5. The soil and groundwater circulation remediation well device according to claim 1, characterized in that, The device further includes: The agent injection pipeline has its port located at the height of the upper screen tube section and outside the upper screen tube section; the upstream of the agent injection pipeline is connected in sequence to the agent tank, the injection pump and the agent injection pressure gauge.

6. The soil and groundwater circulation remediation well device according to claim 1, characterized in that, The outer side of the upper screen tube section is filled with filler medium, the outer side of the closed tube section is filled with bentonite, and the outer side of the lower screen tube section is filled with quartz sand.

7. The soil and groundwater circulation remediation well device according to claim 6, characterized in that, The packing medium is activated carbon or an iron-based supported catalyst.

8. The soil and groundwater circulation remediation well device according to claim 5, characterized in that, The agent is an oxidant, and the repair process forms a catalytic oxidation system.

9. A method for soil groundwater recycling remediation, characterized in that, Using the apparatus as described in any one of claims 1 to 8, the method includes the following steps: A. Place the uninflated flexible airbag unit into the well body which has an upper screen pipe section, a closed pipe section and a lower screen pipe section, and inject the repair agent into the soil at the corresponding position outside the upper screen pipe section. B. Inflate the airbag through the inflation pipeline so that the side wall of the inflated airbag is tightly attached to the well wall and holds it tightly. The airbag expands and reaches the preset pressure. The liquid level in the well rises and the water in the upper part of the airbag is discharged from the upper screen pipe section into the soil under positive pressure. C. After the pressure inside and outside the well reaches equilibrium, the gas in the airbag is evacuated through the air extraction pipeline. Under negative pressure, water enters the well from the soil in the lower screen pipe section. This intermittent inflation and deflation completes the circulation of groundwater in the soil and the well.

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