Permeable reactive barrier-circulation well combined management unit, system and method for repairing groundwater

Abstract

The permeable reaction wall-circulating well combined control unit, system and method for repairing groundwater belong to the field of groundwater repair. The water-facing surface of the permeable reaction wall module is arranged with a water-permeable layer, and the water-facing surface of the circulating well module is provided with a low-permeability barrier layer, so that the inside of the permeable reaction wall module and the circulating well module forms a semi-closed treatment area. The middle part of the circulating well module in the height direction is filled with low-permeability materials to form a low-permeability filler layer, and the upper and lower parts of the low-permeability filler layer are respectively formed with an upper high-permeability filler area and a lower high-permeability filler area filled with high-permeability materials. When the circulating well module is started, the groundwater forms a circulating flow field in the semi-closed treatment area in the order of the permeable reaction wall module, the lower high-permeability filler area, the channel in the well pipe, the upper high-permeability filler area and the permeable reaction wall module. The scheme provided by the present application is simple and easy to implement, and has strong economic practicality, and can be widely applied in the field of groundwater repair technology.

Description

Technical Field

[0001] This invention relates to the field of contaminated groundwater remediation, specifically to a permeable reactive barrier-circulating well combined control unit, system, and method for remediating groundwater. Background Technology

[0002] my country's soil and groundwater remediation industry has developed for two to three decades. In recent years, as decommissioned contaminated sites have gradually begun or completed remediation work, the industry has focused more on the remediation of in-service contaminated sites. However, due to the stringent requirements for remediation construction at in-service sites and the fact that the land use designation is unlikely to change in the short term, the need for remediation is not urgent. To achieve the goal of preventing pollution from spreading beyond the region, the industry has gradually proposed various pollution control technologies applicable to in-service sites.

[0003] Permeable reactive barrier (PRB) technology is a commonly used in-situ control and treatment technology in groundwater remediation. It uses a permeable reactive barrier to intercept and remediate groundwater pollution plumes. Various patents, such as CN114735800A, CN115259544A, and CN115636460A, have improved PRB technology through innovations in technical principles, improvements in construction processes, and enhancements in filler materials. However, the application of PRB technology is always limited. For example, the capacity of the underground reactive barrier medium is limited, making it impossible to remove pollutants indefinitely. For high concentrations of pollutants, the removal energy and capacity must be considered, which can sometimes shorten the lifespan of the PRB. Furthermore, the reactions within the reactive medium can lead to precipitation, altering the flow field of groundwater in and around the reactive barrier. Blockage of the reactive medium can cause PRB failure.

[0004] Circulating groundwater well (GCW) technology is also considered a promising in-situ groundwater remediation technology. Its principle involves injecting gas into the well to forcibly disturb the aquifer, enhancing groundwater flow and creating a circulating flow field. This continuously carries pollutants from the aquifer into the well for treatment. Various patents, such as CN115849617A and CN115504623A, have improved GCW technology through internal component reinforcement, filler reinforcement, and technological coupling. However, the circulation of GCW technology is limited by soil permeability (it can only be used in soils with good permeability), which restricts its widespread application.

[0005] Patent CN115636464A proposes the idea of ​​embedding GCW into the PRB module. Its essence is to set up a PRB module within the groundwater circulation flow field formed by the GCW module, so that when the groundwater circulates under the action of the GCW module, it passes through the PRB module, thus achieving joint repair of the groundwater.

[0006] However, this structure, on the one hand, does not take into account the secondary pollution that may be caused by the interaction between GCW and groundwater, and on the other hand, still cannot effectively solve the problems mentioned above, such as "the circulation of GCW technology is limited by soil permeability", "the underground reactive wall medium in the PRB module has a limited capacity and cannot remove pollutants indefinitely", and "the interaction in the reactive medium may cause the precipitation of substances, which may change the flow field of groundwater in and around the reactive wall, and the blockage of the reactive medium may cause the PRB to fail". Summary of the Invention

[0007] The purpose of this invention is to provide a combined management and control unit, system, and method for groundwater remediation based on existing permeable reactive wall modules and circulating well modules. This combined approach effectively addresses the problem of reactive wall clogging under low hydraulic gradients and low-permeability soils. It also effectively removes volatile pollutants adsorbed in the packing material of the permeable reactive wall module, significantly extending its service life and facilitating long-term management and remediation. Simultaneously, it enables the circulating well module to act on the circulating well packing layer, avoiding the soil permeability constraints inherent in the circulating well module itself. Based on the pollutant capture by the permeable reactive wall module, efficient pollutant removal can be achieved throughout the entire permeable reactive wall-circulating well system.

[0008] The technical solution adopted by the present invention to achieve the above-mentioned technical objectives is as follows: a permeable reactive wall-circulating well joint control unit, comprising a circulating well module with a well pipe and at least one permeable reactive wall module connected to the circulating well module, wherein the permeable reactive wall module is filled with highly permeable adsorbent filler, a permeable layer is arranged on the water-facing side of the permeable reactive wall module, and a low-permeability barrier layer is set on the water-facing side of the circulating well module, so that the interior of the permeable reactive wall module and the circulating well module forms a semi-closed treatment zone; the middle part of the circulating well module in the height direction is filled with low-permeability material to form a low-permeability filler layer, and an upper high-permeability filler area and a lower high-permeability filler area filled with high-permeability material are formed above and below the low-permeability filler layer, respectively; a permeable perforation area is provided on the side wall of the well pipe, and when the circulating well module is started, the groundwater forms a circulating flow field in the semi-closed treatment zone along the sequence of the permeable reactive wall module, the lower high-permeability filler area, the channel in the well pipe, the upper high-permeability filler area, and the permeable reactive wall module.

[0009] As another optimized solution for the aforementioned permeable reactive wall-circulating well joint control unit, the top of the well pipe is sealed with a low-permeability material.

[0010] As another optimized solution for the aforementioned permeable reactive wall-circulating well joint control unit, the sidewall of the well pipe is provided with permeable hole areas from top to bottom, or permeable hole areas are provided only at the positions corresponding to the upper high-permeability filling area and the lower high-permeability filling area.

[0011] As another optimized solution for the aforementioned permeable reactive wall-circulating well joint control unit, at least one side of the permeable reactive wall module is provided with a barrier wall to guide groundwater into the permeable reactive wall module.

[0012] As another optimized solution for the aforementioned permeable reactive wall-circulating well joint control unit, the circulating well module has two symmetrically arranged permeable reactive wall modules.

[0013] As another optimized solution for the above-mentioned permeable reactive wall-circulating well joint control unit, the length of the circulating well module is 0.6-5m, and the length of the permeable reactive wall module is 2-8m.

[0014] As another optimized solution for the aforementioned permeable reactive wall-circulating well joint control unit, the thickness of the circulating well module is no greater than the thickness of the permeable reactive wall module, so as to avoid direct interaction between the circulating flow field and groundwater.

[0015] As another optimized solution for the above-mentioned permeable reactive wall-circulating well joint control unit, the thickness ratio of the circulating well module and the permeable reactive wall module is 1:1-3.

[0016] As another optimized solution for the above-mentioned permeable reactive wall-circulating well joint control unit, the diameter of the well pipe is not less than 50mm, and the ratio of the diameter of the well pipe to the thickness of the circulating well module is 1:1.2-2.

[0017] As another optimized scheme for the above-mentioned permeable reactive wall-circulating well joint control unit, the height ratio of the lower high-permeability filling zone to the low-permeability filling layer is 1:0.5-2, and the height ratio of the lower high-permeability filling zone to the upper high-permeability filling zone is 1:0.5-2.

[0018] As another optimized solution for the aforementioned permeable reactive wall-circulating well combined control unit, the low-permeability material has a permeability coefficient of no more than 10. -7 Materials with a speed of cm / s.

[0019] As another optimized option for the aforementioned permeable reactive wall-circulating well combined control unit, the high-permeability material has a permeability coefficient of 10. -2 -10 -3 Materials with a speed of cm / s.

[0020] As another optimized solution for the aforementioned permeable reactive wall-circulating well joint control unit, the highly permeable adsorption packing material is a physical, chemical, biological, or multi-effect packing material such as activated carbon or molecular sieve.

[0021] A permeable reactive wall-circulating well joint control system, comprising at least one of the aforementioned permeable reactive wall-circulating well joint control units.

[0022] The method for combined remediation of groundwater using a permeable reactive barrier and circulating well includes the following steps:

[0023] 1) A permeable reactive wall module is provided on at least one side of the circulating well module and connected to it. The permeable reactive wall module is filled with highly permeable adsorbent filler and a permeable layer is provided on its water-facing side. A low-permeability barrier layer is provided on the water-facing side of the circulating well module, thereby forming a semi-closed treatment area where only the permeable reactive wall module interacts with the groundwater.

[0024] 2) The circulating well module is filled with high-permeability material, low-permeability material and high-permeability material from bottom to top, thereby forming a lower high-permeability filling zone, a low-permeability filling layer and an upper high-permeability filling zone;

[0025] 3) Periodically activate the auxiliary equipment of the well pipe in the circulation well module so that the groundwater forms a circulating flow field in the order of permeable reactive wall module, lower high-permeability filler zone, channel in the well pipe, upper high-permeability filler zone and permeable reactive wall module under the hydraulic lifting action in the well pipe. This washes away the high-permeability adsorbent filler in the permeable reactive wall module that interacts with the groundwater and removes pollutants from the well pipe.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1) This invention is based on existing permeable reactive wall modules and circulation well modules, and organically couples the two to treat groundwater pollution remediation. It can not only effectively solve the problem of reactive wall clogging under low hydraulic gradient and low permeability soil, but also effectively remove volatile pollutants adsorbed in the packing of the permeable reactive wall module, significantly improve the service life of the packing, and help the long-term management and remediation of the permeable reactive wall module; at the same time, it can also enable the circulation well module to act on the circulation well packing layer, avoiding the soil permeability constraints of the circulation well module itself. Based on the pollutant capture by the permeable reactive wall module, it can achieve efficient removal of pollutants in the entire permeable reactive wall-circulation well.

[0028] 2) This invention creates a semi-closed treatment zone where only the permeable reactive wall module interacts with the groundwater by setting a permeable reactive wall module connected to the side of the circulating well module, setting a permeable layer on the water-facing side of the permeable reactive wall module, and setting a low-permeability barrier layer on the water-facing side of the circulating well module. In this way, when the circulating well module is not activated, the packing material in the permeable reactive wall module continuously adsorbs pollutants in the groundwater. After accumulating to a certain level, the circulating well module is activated to effectively flush and wash away the packing material, thereby regenerating the packing material. The washed-away pollutants are removed through the well pipe of the circulating well module, ultimately achieving sustainable remediation of groundwater pollution and preventing the circulating well module from releasing pollutants back into the groundwater during operation.

[0029] 3) This invention can effectively remove volatile pollutants adsorbed in the packing of the permeable reactive wall module, significantly improve the service life of the packing, and alleviate the problem of reactive wall clogging under low hydraulic gradient and low permeability soil, which is conducive to the long-term management and repair of the permeable reactive wall module. At the same time, by enabling the circulation well module to act on the circulation well packing layer, it also avoids the soil permeability constraint of the circulation well module itself. Based on the capture of pollutants by the permeable reactive wall, it can achieve efficient removal of pollutants in the entire permeable reactive wall-circulation well module, which is conducive to expanding the site applicability of the permeable reactive wall and circulation well module.

[0030] 4) The circulating well module of this invention adopts a convenient single-well pipe well construction scheme, which reduces the construction difficulty and cost, and enables the circulating well technology to be well extended and extended, providing a more reliable option for in-situ remediation of in-service sites.

[0031] 5) The solution provided by this invention is simple, easy to implement, economical and practical, and can be widely applied in the field of groundwater remediation technology. Attached Figure Description

[0032] Figure 1 This is a top view of the structure of the present invention;

[0033] Figure 2 for Figure 1 A schematic diagram of the structure in the height direction;

[0034] Attached reference numerals: 1. Barrier wall; 2. Permeable reactive wall module; 3. Circulation well module; 301. Upper high-permeability filling zone; 302. Low-permeability filling layer; 303. Lower high-permeability filling zone; 4. Well pipe; 401. Permeable hole zone; 402. Channel; 5. Low-permeability barrier layer. Detailed Implementation

[0035] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. Parts not explained in the following embodiments of the present invention, such as the supporting facilities of the circulating well module, the specific structure and operation process for eliminating pollution, as well as the construction and construction of the circulating well module, the construction and construction of the permeable reactive wall module, the construction and construction of the barrier wall, etc., are all prior art known or should be known by those skilled in the art.

[0036] Example 1

[0037] Permeable reactive wall-circulating well integrated control unit, such as Figure 1 and 2 As shown, it includes a circulation well module 3 with a well pipe 4 and at least one permeable reactive wall module 2 connected to the circulation well module 3. Figure 1 and Figure 2The image shows two symmetrically arranged permeable reactive wall modules 2. The line connecting these two modules can be aligned with the groundwater flow direction, tilted at a certain angle, or perpendicular. The circulation well module 3 and the permeable reactive wall module 2 are mature modules in existing technology, and their structure and principles are publicly available and will not be elaborated upon here. The permeable reactive wall module 2 is filled with highly permeable adsorption filler to adsorb and intercept pollutant plumes in the groundwater. A permeable layer is arranged on the water-facing side of the permeable reactive wall module 2, which can be a permeable high-permeability filler layer or a shaped water distribution structure. A low-permeability barrier layer 5 is arranged on the water-facing side of the circulation well module 3, so that the interiors of the permeable reactive wall module 2 and the circulation well module 3 form a semi-closed treatment zone. The water-facing side of the circulation well module 3 and the permeable reactive wall module 2 refers to the surface in contact with groundwater. The permeable layer interacts with the groundwater, allowing it to enter the permeable reactive wall module 2 and be absorbed by the highly permeable adsorption filler. The low-permeability barrier layer 5 is used to prevent direct interaction between groundwater and the circulation well module 3, i.e., groundwater directly entering the circulation well module 3, or groundwater in the circulation well module 3 flowing out directly without passing through the permeable reactive wall module 2; the middle part of the circulation well module 3 in the height direction is filled with low-permeability material to form a low-permeability filler layer 302, and an upper high-permeability filler area 301 and a lower high-permeability filler area 303 filled with high-permeability material are formed above and below the low-permeability filler layer 302, respectively; the side wall of the well pipe 4 has permeability. The permeable pore area 401 consists of several permeable pores distributed around the side wall of the well pipe 4 within a certain height range. The permeable pore area 401 on the side wall of the well pipe 4 is set in advance. When the circulating well module 3 is started, the groundwater relies on the hydraulic lifting effect in the well pipe 4 to form a circulating flow field in the semi-closed treatment area, along the sequence of the permeable reactive wall module 2, the lower high permeability filler area 303, the channel 402 in the well pipe 4, the upper high permeability filler area 301, and the permeable reactive wall module 2.

[0038] In this embodiment, the highly permeable adsorption filler filling the permeable reactive wall module 2 is physical, chemical, biological or multi-effect filler such as activated carbon and molecular sieve. In specific implementation, the filler can be a single type of physical or chemical filler such as activated carbon and molecular sieve, or a mixture of multiple physical fillers, or a porous adsorption filler loaded with chemical or biological components, or other multi-effect fillers.

[0039] In this embodiment, the low-permeability material has a permeability coefficient of no more than 10. -7 Materials with a speed of cm / s; bentonite, cement, and other materials can be selected.

[0040] In this embodiment, the high-permeability material has a permeability coefficient of 10. -2 -10 -3 For materials with a particle size of cm / s, materials such as quartz sand, glass sand, and perlite of appropriate particle size can be selected.

[0041] In this embodiment, the top of the well pipe 4 is sealed with a low-permeability material to prevent groundwater from flowing out from the top of the well pipe 4, so that all groundwater entering the well pipe 4 circulates within a semi-closed treatment area. The low-permeability material here has a permeability coefficient of no more than 10, as mentioned earlier. -7 Materials with a flow rate of cm / s, such as bentonite and cement, can also be sealed with metal plates.

[0042] The above embodiments are basic implementations of the present invention. Improvements and limitations can be made based on the above to obtain the following embodiments:

[0043] Example 2

[0044] This embodiment further defines the permeable hole area 401 on the well pipe 4 in Embodiment 1. Its main structure is the same as in Embodiment 1, but the limitation lies in that: the sidewall of the well pipe 4 is provided with permeable hole areas 401 from top to bottom, meaning the sidewall of the well pipe 4 is covered with permeable holes. However, due to the presence of the low-permeability filler layer 302 in the middle, the permeable holes corresponding to this layer cannot function, and groundwater cannot enter the low-permeability filler layer 302. Alternatively, permeable hole areas 401 may only be provided at positions corresponding to the upper high-permeability filler area 301 and the lower high-permeability filler area 303. Figure 2 As shown, at this time, the height of the permeable pore area 401 can be level with the height of the upper high-permeability filling area 301 or the lower high-permeability filling area 303, or it can be less than the height of the upper high-permeability filling area 301 or the lower high-permeability filling area 303, that is, it only occupies a part of the height range of the upper high-permeability filling area 301 or the lower high-permeability filling area 303.

[0045] Example 3

[0046] This embodiment is an improvement on Embodiment 1. Its main structure is the same as Embodiment 1, but the improvement lies in that: at least one side of the permeable reactive wall module 2 is provided with a barrier wall 1 to guide groundwater into the permeable reactive wall module 2, such as... Figure 1 and 2 As shown, there is a barrier wall 1. The barrier wall 1 is generally located along the direction of groundwater flow and away from the side of the circulation well module 3. The barrier wall 1 is made of low-permeability material. Its purpose is to prevent groundwater from passing through, thereby guiding the water flow into the permeable reactive wall module 2. Its thickness and height are set according to the actual hydrogeological conditions.

[0047] Example 4

[0048] This embodiment further defines the circulating well module 3 and the permeable reactive wall module 2 in Embodiment 1. Its main structure is the same as in Embodiment 1, but the definition is as follows: the length of the circulating well module 3 is 0.6-5m. In specific implementation, the length of the circulating well module 3 can be 0.6m, 1m, 2m, 3m, 4m, 5m, or any specific value within the range of 0.6-5m. The length of the permeable reactive wall module 2 is 2-8m. In specific implementation, the length of the permeable reactive wall module 2 can be an integer such as 2m, 3m, 4m, 5m, 6m, 7m, 8m, or any non-integer value within the range of 2-8m. The lengths of the circulating well module 3 and the permeable reactive wall module 2 refer to the length of their projections in the horizontal plane.

[0049] In this embodiment, the thickness of the circulating well module 3 is no greater than the thickness of the permeable reactive wall module 2 to avoid direct interaction between the circulating flow field and the groundwater. The thickness of the circulating well module 3 and the permeable reactive wall module 2 refers to the thickness or width of the projection formed by these two modules in the horizontal plane. Generally, the thickness ratio of the circulating well module 3 and the permeable reactive wall module 2 is 1:1-3. In specific implementations, the thickness ratio of the circulating well module 3 and the permeable reactive wall module 2 can be any specific value among 1:1, 1:1.5, 1:2, 1:2.5, 1:3, or 1:1-3.

[0050] In this embodiment, the diameter of the well pipe 4 is not less than 50mm, and the ratio of the diameter of the well pipe 4 to the thickness of the circulation well module 3 is 1:1.2-2. In specific implementation, the diameter of the well pipe 4 should meet the size requirements of the internal components, and can be any specific size design of 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm or other not less than 50mm. However, it should be noted that the diameter of the well pipe 4 should not be too large to avoid adverse effects on the construction of the circulation well. The ratio of the diameter of the well pipe 4 to the thickness of the circulation well module 3 can be any specific ratio value among 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2 or 1:1.2-2.

[0051] Example 5

[0052] This embodiment further defines the circulating well module 3 in Embodiment 1. Its main structure is the same as in Embodiment 1, but the limitation lies in that: the circulating well module 3 should be filled with high-permeability, low-permeability, and high-permeability fillers sequentially from bottom to top, thus forming a lower high-permeability filler zone 303, a low-permeability filler layer 302, and an upper high-permeability filler zone 301. The filling height of the three sections should be specifically designed according to the pollutant situation. The height ratio of the lower high-permeability filler zone 303 to the low-permeability filler layer 302 is 1:0.5-2, and the height ratio of the lower high-permeability filler zone 303 to the upper high-permeability filler zone 301 is... The height ratio of 301 is 1:0.5-2. In specific implementation, the filling height ratio of the lower high-permeability material to the middle barrier material can be any one of the following specific ratios: 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, or 1:0.5-2. The filling height ratio of the lower high-permeability material to the upper high-permeability material can be any one of the following specific ratios: 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, or 1:0.5-2.

[0053] Example 6

[0054] A permeable reactive wall-circulating well joint control system is used to remediate groundwater. Based on factors such as the area of ​​groundwater pollution, at least one set of permeable reactive wall-circulating well joint control units as described in Examples 1-6 above is designed in the control system. The spacing between these control units is adjusted according to the actual situation.

[0055] Example 7

[0056] Methods for groundwater remediation using a combination of permeable reactive barriers and circulating wells, such as... Figure 1 and 2 As shown, it includes the following steps:

[0057] 1) A permeable reactive wall module 2 is provided on at least one side of the circulating well module 3 and is connected to it. The permeable reactive wall module 2 is filled with highly permeable adsorbent filler and a permeable layer is provided on its water-facing side. A low-permeability barrier layer 5 is provided on the water-facing side of the circulating well module 3, thereby forming a semi-closed treatment area in which only the permeable reactive wall module 2 interacts with the groundwater.

[0058] 2) The circulating well module 3 is filled with high-permeability material, low-permeability material and high-permeability material from bottom to top, thereby forming the lower high-permeability filling zone 303, the low-permeability filling layer 302 and the upper high-permeability filling zone 301.

[0059] 3) Periodically activate the auxiliary equipment of the well pipe 4 in the circulating well module 3 so that the groundwater forms a circulating flow field in the order of the permeable reactive wall module 2, the lower high-permeability filler zone 303, the channel 402 in the well pipe 4, the upper high-permeability filler zone 301 and the permeable reactive wall module 2 under the hydraulic lifting effect in the well pipe 4. This washes away the high-permeability adsorption filler in the permeable reactive wall module 2 that interacts with the groundwater, thereby removing pollutants and regenerating the filler so that it can repeatedly adsorb pollutants. The washed-out pollutants are finally removed from the well pipe 4.

Claims

1. A combined permeable reactive barrier-circulation well unit, comprising a circulation well module (3) with a well pipe (4) and at least one permeable reactive barrier module (2) connected to the circulation well module (3) and filled with a highly permeable adsorptive filler in the permeable reactive barrier module (2), characterized in that: The water-facing surface of the permeable reaction wall module (2) is arranged with a water-permeable layer, and the water-facing surface of the circulation well module (3) is arranged with a low-permeability barrier layer (5), so that the inside of the permeable reaction wall module (2) and the circulation well module (3) forms a semi-closed treatment area; the middle part of the circulation well module (3) in the height direction is filled with a low-permeability material to form a low-permeability filler layer (302), and the upper and lower parts of the low-permeability filler layer (302) are respectively arranged with an upper high-permeability filler area (301) and a lower high-permeability filler area (303) filled with high-permeability materials, and the side wall of the well pipe (4) is provided with a water-permeable hole area (401), and when the circulation well module (3) is started, the groundwater in the semi-closed treatment area forms a circulation flow field along the permeable reaction wall module (2), the lower high-permeability filler area (303), a channel (402) in the well pipe (4), the upper high-permeability filler area (301) and the permeable reaction wall module (2) in sequence. The thickness of the circulation well module (3) is not greater than the thickness of the permeable reaction wall module (2), so as to avoid direct interaction between the circulation flow field and the groundwater; at least one side of the permeable reaction wall module (2) is provided with a barrier wall (1) for guiding the groundwater into the permeable reaction wall module (2).

2. The permeable reactive barrier-circulation well combined management and control unit according to claim 1, characterized in that: The top end of the well pipe (4) is sealed by a low-permeability material.

3. The permeable reactive barrier-circulation well combined management and control unit according to claim 1, characterized in that: The side wall of the well pipe (4) is provided with a water-permeable hole area (401) from top to bottom, or only provided with a water-permeable hole area (401) at positions corresponding to the upper high-permeability filler area (301) and the lower high-permeability filler area (303).

4. The permeable reactive barrier-circulation well combined management and control unit according to claim 1, characterized in that: The circulation well module (3) is provided with two symmetrical permeable reaction wall modules (2).

5. The permeable reactive barrier-circulation well combined management and control unit according to claim 1, characterized in that: The length of the circulation well module (3) is 0.6-5m, and the length of the permeable reaction wall module (2) is 2-8m.

6. The permeable reactive barrier-circulation well combined management and control unit according to claim 1, characterized in that: The thickness ratio of the circulation well module (3) to the permeable reaction wall module (2) is 1:1-3.

7. The permeable reactive barrier-circulation well combined management and control unit according to claim 1, characterized in that: The diameter of the well pipe (4) is not less than 50mm, and the ratio of the diameter of the well pipe (4) to the thickness of the circulation well module (3) is 1:1.2-2.

8. The permeable reactive barrier-circulation well combined management and control unit according to claim 1, characterized in that: The height ratio of the lower high-permeability filler area (303) to the low-permeability filler layer (302) is 1:0.5-2, and the height ratio of the lower high-permeability filler area (303) to the upper high-permeability filler area (301) is 1:0.5-2.

9. The permeable reactive barrier-circulation well combined management and control unit according to claim 1, characterized in that: The low permeability material is a material having a permeability coefficient of no more than 10 -7 cm / s.

10. The permeable reactive barrier-circulation well combined management and control unit according to claim 1, characterized in that: The high permeable material is a material with a permeability coefficient of 10 -2 -10 -3 cm / s.

11. The permeable reactive barrier-circulation well combined management and control unit according to claim 1, characterized in that: The high-permeability adsorptive filler is a physical, chemical, biological or multi-effect filler.

12. A permeable reactive barrier-circulation well combined management system, characterized in that: The system comprises at least one permeable reaction wall-circulation well combined control unit according to any one of claims 1-11.

13. A method for remediation of groundwater by a combination of permeable reactive barrier and recirculation well, characterized in that, The system comprises the following steps: 1) arranging a permeable reaction wall module (2) on at least one side of the circulation well module (3) and in communication with the circulation well module (3), filling the permeable reaction wall module (2) with high-permeability adsorptive fillers, arranging a water-permeable layer on the water-facing surface of the permeable reaction wall module (2), arranging a low-permeability barrier layer (5) on the water-facing surface of the circulation well module (3), so as to form a semi-closed treatment area in which only the permeable reaction wall module (2) interacts with the groundwater; 2) sequentially filling the circulation well module (3) from bottom to top with high-permeability materials, low-permeability materials and high-permeability materials, so as to form a lower high-permeability filler area (303), a low-permeability filler layer (302) and an upper high-permeability filler area (301). 3) periodically start the auxiliary equipment of the well pipe (4) in the circulating well module (3) to make the groundwater form a circulating flow field along the permeable reaction wall module (2), the lower high-permeable filling area (303), the channel (402) in the well pipe (4), the upper high-permeable filling area (301) and the permeable reaction wall module (2) in sequence under the hydraulic lifting effect of the well pipe (4), so as to elute the high-permeable adsorptive filling in the permeable reaction wall module (2) interacting with the groundwater, and make the pollutants removed from the well pipe (4).

Images