Oxygen injection permeable reactive barrier system for in-situ remediation of underground water

Abstract

The utility model belongs to the technical field of groundwater remediation, and particularly relates to an oxygen injection permeable reactive barrier system for groundwater in-situ remediation, which comprises an underground reaction tank, and the upstream end and the downstream end of the underground reaction tank are respectively provided with an upstream face semi-enclosed clamping groove and a downstream face semi-enclosed clamping groove. A first permeable reactive barrier is vertically and slidably mounted in the upstream face half-wrapped clamping groove, a second permeable reactive barrier is vertically and slidably mounted in the downstream face half-wrapped clamping groove, and an oxygen injection groove is formed between the first permeable reactive barrier and the second permeable reactive barrier. And a gas injection device for injecting oxygen into underground water in the oxygen injection tank is arranged outside the oxygen injection tank. The oxygen injection tank is additionally arranged between the two permeable reactive barriers, the oxidation-reduction environment of underground water is changed by injecting oxygen-containing air, the activity of aerobic microorganisms is improved, and pollutants are promoted to be oxidized, decomposed or degraded so as to be reduced; through cooperation of the first permeable reactive barrier, the oxygen injection tank and the second permeable reactive barrier, simultaneous in-situ treatment of heavy metal pollutants and organic pollutants in underground water is realized, and effluent quality is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of groundwater restoration, and in particular relates to an oxygen-injected permeable reaction wall system for in-situ restoration of groundwater. Background Art

[0002] Groundwater pollution incidents often occur in contaminated sites, legacy mining areas, tailings ponds, landfills and other scenarios. Commonly used groundwater remediation technologies include: extraction treatment, in-situ injection, permeable reaction walls, etc. Among them, the permeable reaction wall is an in-situ remediation method that is suitable for a variety of scenarios and will not damage the groundwater flow field and will not cause secondary pollution to the groundwater due to the injection of remediation agents. Based on the analysis of hydrogeological conditions, an underground continuous reaction wall is directly constructed in the runoff path where the pollution halo spreads downstream. The high permeability and hydraulic conditions of the permeable reaction wall are used to make the permeable reaction wall an advantageous corridor for groundwater. According to the type of pollutants to be repaired, physical, chemical or biological methods are used to bury the corresponding agents and fillers in the wall to reduce pollutants in the groundwater. The permeable reaction wall in-situ remediation technology does not require additional water storage containers and water treatment equipment, and the interference to the ecological environment is also small.

[0003] However, the application of permeable reaction walls in actual engineering projects is still relatively rare. The main limiting factors are as follows: (1) The sustainability of permeable reaction walls in treating pollutants is poor. Once the reagents react completely or the fillers are blocked, the reaction wall becomes ineffective. (2) For groundwater in a reducing environment, the permeable reaction wall has a relatively poor effect on treating organic pollution. (3) While the permeability of the reaction wall facilitates groundwater infiltration, it also results in a shorter residence time of groundwater and insufficient reaction. Utility Model Content

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the utility model is to provide an oxygen-injected permeable reaction wall system for in-situ groundwater remediation, which can ensure the effectiveness of the permeable reaction wall and the sustainability of the reaction, improve the treatment effect of organic pollutants in groundwater, and at the same time ensure the residence time of contaminated groundwater in the reaction wall to promote sufficient reaction.

[0005] To achieve the above-mentioned purpose, the technical solution of the utility model is an oxygen-injected permeable reaction wall system for in-situ groundwater remediation, comprising an underground reaction tank, wherein the water-facing end and the water-retaining end of the underground reaction tank are respectively provided with a water-facing surface half-enclosed type slot and a water-retaining surface half-enclosed type slot, a first permeable reaction wall is vertically slidably installed in the water-facing surface half-enclosed type slot, and a second permeable reaction wall is vertically slidably installed in the water-retaining surface half-enclosed type slot, an oxygen injection tank is provided between the first permeable reaction wall and the second permeable reaction wall, and a gas injection device for injecting oxygen into the groundwater in the oxygen injection tank is provided on the top of the oxygen injection tank.

[0006] As one of the embodiments, the water-facing side and the water-receiving side of the first permeable reaction wall are respectively provided with a first water-facing surface water-blocking baffle and a first water-receiving surface water-blocking baffle, and the first water-facing surface water-blocking baffle and the first water-receiving surface water-blocking baffle are respectively vertically slidably installed on the half-enclosed card groove of the water-facing surface.

[0007] As one of the embodiments, the water-facing side and the water-receiving side of the second permeable reaction wall are respectively provided with a second water-facing surface water-blocking baffle and a second water-receiving surface water-blocking baffle, and the second water-facing surface water-blocking baffle and the second water-receiving surface water-blocking baffle are respectively vertically slidably installed on the water-receiving surface half-enclosed groove.

[0008] As one of the implementation modes, the bottom of the underground reaction tank penetrates at least 1 meter into the relative waterproof layer, and the bottom ends of the waterproof baffles on the water-facing side and the waterproof baffles on the water-receiving side can extend below the bottom surface of the underground reaction tank.

[0009] As one of the implementation modes, the half-enclosed card groove on the water-facing surface and the half-enclosed card groove on the water-receiving surface are both U-shaped structures, and the openings are arranged opposite to each other; the side walls of the half-enclosed card groove on the water-facing surface and the half-enclosed card groove on the water-receiving surface that are perpendicular to the flow direction of groundwater are both provided with water permeable holes.

[0010] As one of the embodiments, an inserted water-blocking baffle is provided in the first permeable reaction wall, the water-facing side of the inserted water-blocking baffle is a flocculation sedimentation zone, and a flocculant dosing device for adding flocculant into the flocculation sedimentation zone is provided on the top of the flocculation sedimentation zone.

[0011] As one of the implementation modes, the top end of the inserted waterproof baffle is flush with the current groundwater level, and the bottom end extends below the bottom surface of the underground reaction tank.

[0012] As one of the embodiments, the back water side of the inserted water-blocking baffle is a reaction zone, and the reaction zone is provided with a first gabion stone cage slidably connected to the half-enclosed groove on the water-facing surface, the bottom of the first gabion stone cage is filled with sand and gravel filter material, the top of the first gabion stone cage is filled with reaction filler, and the bottom of the reaction filler is located below the top surface of the inserted water-blocking baffle.

[0013] As one of the implementation modes, a stainless steel lattice is installed on the top of the flocculation and sedimentation zone and the top of the oxygen injection tank, and a multi-parameter tracking monitoring meter is provided in the flocculation and sedimentation zone and the oxygen injection tank.

[0014] As one of the implementation modes, the second permeable reaction wall comprises a second gabion stone cage slidably connected to the half-enclosed groove on the back water surface, and the second gabion stone cage is filled with activated carbon filter material.

[0015] Compared with the prior art, the utility model has the following beneficial effects:

[0016] (1) The utility model adds an oxygen injection tank between two permeable reaction walls, and changes the redox environment of groundwater by injecting oxygen-containing air, thereby increasing the activity of aerobic microorganisms, promoting the oxidation and decomposition or degradation of pollutants, thereby reducing them and improving the treatment effect of organic pollutants in groundwater;

[0017] (2) The oxygen-injected permeable reaction wall system of the utility model can simultaneously treat heavy metal pollutants and organic pollutants in groundwater in situ, remove particulate matter and heavy metals in the water through the first permeable reaction wall, promote the oxidation and decomposition or degradation of pollutants through the oxygen injection tank, and effectively capture the remaining pollutants in the water through the second permeable reaction wall to ensure the quality of the effluent water;

[0018] (3) The permeable reaction wall of the utility model is vertically slidably installed in a half-packed slot in the underground reaction tank. When the reagent becomes ineffective, it can be pulled out and replaced, thereby ensuring the effectiveness of the reaction reagent and filler and the sustainability of the reaction;

[0019] (4) The utility model provides a water-facing baffle plate and a water-retaining baffle plate on the water-facing side and the water-retaining side of the permeable reaction wall, respectively, which can be lifted up and lowered. This allows contaminated groundwater to stay in the reaction wall for a certain period of time, allowing it to react more fully and allowing pollutants to be removed more effectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A structural diagram of an oxygen-injected permeable reaction wall system for in-situ groundwater remediation provided by an embodiment of the utility model;

[0022] Figure 2 A top view of an oxygen-injected permeable reactive wall system for in-situ groundwater remediation provided by an embodiment of the utility model;

[0023] In the figure: 1. relative water-proof layer; 2. groundwater flow direction; 3. ground; 4. flocculant dosing device; 401. check valve; 402. dosing pipe; 5. first water-proof baffle on the front water surface; 501. side slide rail of the first water-proof baffle on the front water surface; 6. half-wrapped card slot on the front water surface; 7. sand and gravel filter material; 8. internal water-proof baffle; 9. reaction filler; 10. multi-parameter tracking monitoring meter; 11. first gabion stone cage; 1101. gabion stone cage slide rail; 12. bentonite; 13. first water-proof baffle on the back water surface; 1301. side slide rail of the first water-proof baffle on the back water surface Rail; 14. Oxygen injection tank; 15. Gas injection device; 16. Second water-facing baffle; 1601. Second water-facing baffle side slide rail; 17. Activated carbon filter material; 18. Back water surface half-wrapped card slot; 19. Second back water surface baffle; 1901. Second back water surface baffle side slide rail; 20. Current groundwater level; 21. Photovoltaic power generation system; 22. PLC controller; 23. Flocculation sedimentation area; 24. Movable sludge hopper; 25. First permeable reaction wall; 26. Second permeable reaction wall; 27. Stainless steel lattice. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0026] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present utility model, unless otherwise specified, "plurality" means two or more.

[0027] like Figure 1-Figure 2As shown, this embodiment provides an oxygen-injected permeable reaction wall system for in-situ groundwater remediation, including an underground reaction tank, wherein the water-facing end and the water-receiving end of the underground reaction tank are respectively provided with a water-facing surface half-enclosed groove 6 and a water-receiving surface half-enclosed groove 18, a first permeable reaction wall 25 is vertically slidably installed in the water-facing surface half-enclosed groove 6, and a second permeable reaction wall 26 is vertically slidably installed in the water-receiving surface half-enclosed groove 18, an oxygen injection tank 14 is arranged between the first permeable reaction wall 25 and the second permeable reaction wall 26, and a gas injection device 15 for injecting oxygen into the groundwater in the oxygen injection tank 14 is arranged on the top of the oxygen injection tank 14. This embodiment upgrades the traditional closed permeable reaction wall structure, adds an oxygen injection trough 14 between the first permeable reaction wall 25 and the second permeable reaction wall 26, changes the redox environment of the groundwater by injecting oxygen-containing air into the runoff path, improves the activity of aerobic microorganisms, utilizes carbon sources and oxygen sources to degrade pollutants in the groundwater, enhances the decomposition and biodegradation of organic pollutants, and reduces the content of organic pollutants in the effluent water.

[0028] To optimize the above embodiment, the first permeable reaction wall 25 is provided with a first water-facing surface water-blocking baffle 5 and a first water-backing surface water-blocking baffle 13 on the water-facing side and the water-backing side, respectively. The first water-facing surface water-blocking baffle 5 and the first water-backing surface water-blocking baffle 13 are respectively vertically slidably installed on the water-facing surface half-wrapped card slot 6. Figure 1 As shown, the water-facing side and the water-retaining side of the first permeable reaction wall 25 are respectively installed with a first water-facing surface waterproof baffle 5 and a first water-retaining surface waterproof baffle 13 which can be lifted up and lowered. The contaminated groundwater can be allowed to stay in the first permeable reaction wall 25 for a certain period of time to ensure sufficient reaction, so that the particulate matter and colloid in the water can be removed more effectively.

[0029] To optimize the above embodiment, the second permeable reaction wall 26 is provided with a second water-facing water-blocking baffle 16 and a second water-backing water-blocking baffle 19 on the water-facing side and the water-backing side, respectively. The second water-facing water-blocking baffle 16 and the second water-backing water-blocking baffle 19 are respectively vertically slidably mounted on the water-backing half-wrapped slot 18. Figure 1 As shown, the water-facing side and the water-receiving side of the second permeable reaction wall 26 are respectively installed with a second water-facing surface waterproof baffle 16 and a second water-receiving surface waterproof baffle 19 which can be lifted up and lowered. The contaminated groundwater can stay in the second permeable reaction wall 26 for a certain period of time to ensure sufficient reaction, so that the remaining pollutants in the water can be removed more effectively.

[0030] Furthermore, the bottom of the underground reaction tank is at least 1m deep relative to the waterproof layer 1, and the bottom ends of the water-front waterproof baffle and the water-retaining waterproof baffle can extend below the bottom surface of the underground reaction tank. Since the bottoms of the first water-front waterproof baffle 5 and the first water-retaining waterproof baffle 13 on both sides of the first permeable reaction wall 25 can be deeper relative to the waterproof layer 1 than the first permeable reaction wall 25, the second permeable reaction wall 26 and the oxygen injection tank 14, and the bottoms of the second water-front waterproof baffle 16 and the second water-retaining waterproof baffle 19 on both sides of the second permeable reaction wall 26 can be deeper relative to the waterproof layer 1 than the first permeable reaction wall 25, the second permeable reaction wall 26 and the oxygen injection tank 14, the water-front waterproof baffle and the water-retaining waterproof baffle can block the runoff of groundwater as much as possible, allowing the contaminated groundwater to stay in the corresponding permeable reaction wall for a certain period of time and react more fully, so that the pollutants can be effectively removed.

[0031] In one embodiment, the half-enclosed card slot 6 on the water-facing side and the half-enclosed card slot 18 on the water-receiving side are both U-shaped structures, and the openings are arranged opposite to each other; the side walls of the half-enclosed card slot 6 on the water-facing side and the half-enclosed card slot 18 on the water-receiving side that are perpendicular to the groundwater flow direction 2 are both provided with water-permeable holes. Figure 1 As shown, a plurality of water-permeable holes are provided on the left side wall of the half-enclosed slot 6 on the water-facing side and perpendicular to the groundwater flow direction 2 and on the left side wall of the half-enclosed slot 18 on the water-receiving side and perpendicular to the groundwater flow direction 2 to facilitate the groundwater to enter the first permeable reaction wall 25.

[0032] Furthermore, if Figure 2 As shown, the water-facing end of the front and rear side walls of the half-enclosed groove 6 arranged along the groundwater flow direction 2 protrudes from its left side wall to form two left and right grooves, the first water-facing baffle 5 is vertically slidably installed in the left groove, the first permeable reaction wall 25 and the first back water baffle 13 are vertically slidably installed in the right groove; the back water-facing half-enclosed groove 18 has its back water end of the two front and rear side walls arranged along the groundwater flow direction 2 protruding from its right side wall to form two left and right grooves, the second water-facing baffle 16 and the second permeable reaction wall 26 are vertically slidably installed in the left groove, and the second back water baffle 19 is vertically slidably installed in the right groove.

[0033] In another embodiment, the water-front half-enclosed slot 6 and the water-retaining half-enclosed slot 18 are both U-shaped structures, and the openings are both facing upward. The first water-front water-blocking baffle 5, the first permeable reaction wall 25 and the first water-retaining water-blocking baffle 13 are all slidably connected to the two side walls of the water-front half-enclosed slot 6, and the second water-front water-blocking baffle 16, the second water-retaining water-blocking baffle 19 and the second permeable reaction wall 26 are all slidably connected to the two side walls of the water-retaining half-enclosed slot 18.

[0034] In this embodiment, the width of the half-enclosed groove 6 on the water-facing surface and the half-enclosed groove 18 on the water-receiving surface is consistent with the width of the underground reaction tank, the length of the half-enclosed groove 6 on the water-facing surface is equal to the sum of the thicknesses of the first permeable reaction wall 25, the first water-facing surface waterproof baffle 5 and the first water-receiving surface waterproof baffle 13, and the length of the half-enclosed groove 18 on the water-receiving surface is equal to the sum of the thicknesses of the second permeable reaction wall 26, the second water-facing surface waterproof baffle 16 and the second water-receiving surface waterproof baffle 19.

[0035] The above embodiment is optimized, an inserted water-blocking baffle 8 is provided in the first permeable reaction wall 25, the water-facing side of the inserted water-blocking baffle 8 is a flocculation sedimentation area 23, and a flocculant dosing device 4 for adding flocculants into the flocculation sedimentation area 23 is provided on the top of the flocculation sedimentation area 23. In order to allow the heavy metal contamination ions in the groundwater to be precipitated and removed as much as possible, the flocculation sedimentation area 23 is provided on the water-facing side of the first permeable reaction wall 25 in this embodiment, and the heavy metal ions in the groundwater are formed into floccules by adding flocculants and precipitated under the action of gravity.

[0036] The dosing pipe 402 of the flocculant dosing device 4 of this embodiment extends from the bottom of the device and is inserted into the groundwater of the flocculation sedimentation area 23. A check valve 401 is installed on the dosing pipe 402. A movable sludge hopper 24 for collecting the generated flocculated sediment is provided at the bottom of the flocculation sedimentation area 23. The lifting rope of the movable sludge hopper 24 is fixed to the surface, and the sediment can be regularly pulled up for treatment.

[0037] In order to ensure the power consumption of the flocculant dosing device 4 and the gas injection device 15, a photovoltaic power generation system 21 can be built in a suitable area around the oxygen injection permeable reaction wall system to generate electricity using solar energy for self-sufficiency.

[0038] Furthermore, the top end of the inserted waterproof baffle 8 is flush with the current groundwater level 20, and the bottom end extends to the relative waterproof layer 1 and is located below the bottom surface of the underground reaction tank.

[0039] In this embodiment, the backwater side of the inserted waterproof baffle 8 is a reaction zone, and the reaction zone is provided with a first gabion stone cage 11 slidably connected to the half-enclosed slot 6 on the water-facing surface, and the bottom of the first gabion stone cage 11 is filled with sand and gravel filter material 7, and the top of the first gabion stone cage 11 is filled with reaction filler 9, and the bottom of the reaction filler 9 is located below the top surface of the inserted waterproof baffle 8. Among them, the reaction filler 9 can select different fillers according to the groundwater pollutants of concern to be treated, such as limestone filler, manganese sand filler, etc.; when the groundwater is acidic, the reaction filler 9 can use limestone filler to increase the pH value of the groundwater; the sand and gravel filter material 7 can remove particulate matter and colloids in the water. Optimally, the top of the reaction filler 9 can be covered with bentonite 12 to prevent the rise of the groundwater level from causing the top of the reaction filler 9 to overflow the filler area.

[0040] Furthermore, the top of the flocculation and sedimentation area 23 and the top of the oxygen injection tank 14 are both installed with stainless steel lattices 27, and the spacing of the stainless steel lattices 27 needs to avoid the risk of personnel falling. The stainless steel lattices 27 on the top of the flocculation and sedimentation area 23 can provide convenience for lowering and lifting the movable sludge hopper 24 and the multi-parameter tracking monitoring meter 10; the stainless steel lattices 27 on the top of the oxygen injection tank 14 can ensure the exposure environment of the oxygen injection tank 14, and the gas injection device 15 can be set up on the stainless steel lattices 27.

[0041] Furthermore, a multi-parameter tracking monitor 10 is provided in the flocculation sedimentation area 23 and the oxygen injection tank 14. The multi-parameter tracking monitor 10 has a replaceable waterproof battery. The gas injection device 15, the flocculant dosing device 4 and the multi-parameter tracking monitor 10 of this embodiment are all connected to the PLC controller 22; the PLC controller 22 can control the start-up and flow regulation of the gas injection device 15 and the flocculant dosing device 4, but does not involve improvements to the program. The multi-parameter tracking monitoring meter 10 in the flocculation and sedimentation area 23 is set on the diving surface, and can monitor the groundwater level and the main pollutant concentration therein in real time, and feed back the monitoring data to the PLC controller 22 in real time. When the data fed back by the multi-parameter tracking monitoring meter 10 in the flocculation and sedimentation area 23 to the PLC controller 22 triggers the set monitoring concentration critical point, the flocculant dosing device 4 will be mobilized to add the agent; the multi-parameter tracking monitoring meter 10 in the oxygen injection tank 14 can monitor the dissolved oxygen content of the groundwater therein in real time, and feed back the monitoring data to the PLC controller 22 in real time. When the data fed back by the multi-parameter tracking monitoring meter 10 in the oxygen injection tank 14 to the PLC controller 22 triggers the set monitoring concentration critical point, the gas injection device 15 will be mobilized to increase the gas injection volume.

[0042] In this embodiment, the second permeable reaction wall 26 includes a second gabion stone cage slidably connected to the back-water half-wrapped slot 18, and the second gabion stone cage is filled with activated carbon filter material 17. The activated carbon filter material 17 uses its porous medium characteristics and large specific surface area to fully adsorb the groundwater after flocculation, adsorption filtration, and oxidation decomposition, effectively capturing the remaining pollutants in the water, and further purifies the water body as the last reaction wall to ensure the quality of the effluent. Optimally, the top of the activated carbon filter material 17 can be covered with bentonite 12 to prevent the groundwater level from rising and causing the top of the activated carbon filter material 17 to overflow the filler area.

[0043] In this embodiment, the specific filling amounts of the sand and gravel filter material 7 and the reaction filler 9 in the first gabion stone cage 11 and the specific filling amount of the activated carbon filter material in the second gabion stone cage are determined according to the pollutant concentration and the reduction target. Under the condition that the depth of the permeable reaction wall is constant, in order to ensure the volume of the pharmaceutical filler and the residence time of the groundwater reaction, the length of each permeable reaction wall and the total length of the oxygen-injected permeable reaction wall system are determined.

[0044] In some embodiments, the first water-facing surface waterproof baffle 5, the first water-receiving surface waterproof baffle 13 and the first gabion stone cage 11 are all vertically slidably installed in the water-facing surface semi-enclosed groove 6 by means of the cooperation of slide rails and slide grooves. Specifically, the first water-facing surface waterproof baffle side slide rails 501 can be vertically installed on both sides of the first water-facing surface waterproof baffle 5, the first water-receiving surface waterproof baffle side slide rails 1301 can be vertically installed on both sides of the first water-receiving surface waterproof baffle 13, and the gabion stone cage slide rails 1101 can be vertically installed on both sides of the first gabion stone cage 11 skeleton. Slide grooves are respectively arranged at positions corresponding to each slide rail on the water-facing surface semi-enclosed groove 6, and the first water-facing surface waterproof baffle 5, the first water-receiving surface waterproof baffle 13 and the first gabion stone cage 11 can be lowered by slidingly cooperating between the slide rails and the corresponding slide grooves. and pulling up; the second water-facing surface waterproof baffle 16, the second water-receiving surface waterproof baffle 19 and the second gabion gabion are all vertically slidably installed in the back surface half-wrapped slot 18 by means of the cooperation of slide rails and slide grooves. Specifically, the second water-facing surface waterproof baffle side slide rails 1601 can be vertically installed on both sides of the second water-facing surface waterproof baffle 16, and the second back surface waterproof baffle side slide rails 1901 can be vertically installed on both sides of the second back surface waterproof baffle 19, and the gabion gabion slide rails can be vertically installed on both sides of the second gabion gabion frame, and slide grooves are respectively arranged on the back surface half-wrapped slot 18 at positions corresponding to each slide rail, and the second water-facing surface waterproof baffle 16, the second back surface waterproof baffle 19 and the second gabion gabion are slidably cooperated with the corresponding slide grooves to realize the lowering and pulling up of the second water-facing surface waterproof baffle 16, the second back surface waterproof baffle 19 and the second gabion gabion. The first gabion stone cage 11 and the second gabion stone of this embodiment can be made of stainless steel. After the reagent filling is completed on the ground 3, the slide rail and the slide groove are aligned and placed in the corresponding half-pack type slot, and the gabion stone cage can be installed in sections according to the length of the reaction wall; after the late reagent filling reaction fails, it is pulled upward and pulled out along the slide groove. After the reagent filling is replaced, the above installation steps are repeated to reset it, thereby ensuring the effectiveness of the reagent filling in the permeable reaction wall. The aperture of the gabion stone cage needs to be smaller than the diameter of the reagent filling.

[0045] The oxygen-injected permeable reactive wall system for in-situ groundwater remediation of this embodiment is usually constructed downstream of the groundwater contamination halo to reduce pollutants in groundwater phreatic water. The construction method is as follows:

[0046] S1. Select a suitable location to dig an underground reaction tank downstream of the groundwater pollution halo, and the bottom of the underground reaction tank should be at least 1m deep relative to the aquiclude.

[0047] S2. After the excavation of the underground reaction tank is completed, a half-enclosed card slot 6 on the water-facing side and a half-enclosed card slot 18 on the water-facing side are constructed at the water-facing side and the water-receiving side of the underground reaction tank respectively;

[0048] S3, vertically slide and install the first water-facing surface baffle 5 and the first water-receiving surface baffle 13 in the half-enclosed slot 6 of the water-facing surface respectively, vertically slide and install the second water-facing surface baffle 16 and the second water-receiving surface baffle 19 in the half-enclosed slot 18 of the water-receiving surface respectively, form an oxygen injection tank 14 between the first water-receiving surface baffle 13 and the second water-receiving surface baffle 16, and drain the sewage left in the reaction tank;

[0049] S4, fill the first gabion stone cage 11 with sand and gravel filter material 7 and reaction filler 9, fill the second gabion stone cage with activated carbon filter material 17, then vertically slide the first gabion stone cage 11 from between the first water-facing surface water-blocking baffle 5 and the first water-receiving surface water-blocking baffle 13 to install it in the half-enclosed card groove 6 on the water-facing surface, and vertically slide the second gabion stone cage from the second water-facing surface water-blocking baffle 16 and the second water-receiving surface water-blocking baffle 19 to install it in the half-enclosed card groove 18 on the water-receiving surface;

[0050] S5. An inserted waterproof baffle 8 is added to the water-facing side of the first gabion stone cage 11, so that a flocculation sedimentation area 23 is formed between the first water-facing waterproof baffle 5 and the inserted waterproof baffle 8; the top of the inserted waterproof baffle 8 is flush with the current groundwater level 20, and the bottom is inserted into the relative waterproof layer 1 and is located below the bottom surface of the underground reaction tank;

[0051] S6. A flocculant dosing device 4 is installed on the top of the flocculation sedimentation zone 23. The dosing pipe 402 of the flocculant dosing device 4 extends from the bottom of the device and is inserted into the groundwater of the flocculation sedimentation zone 23. A movable sludge hopper 24 is installed at the bottom of the flocculation sedimentation zone 23. The lifting rope of the movable sludge hopper 24 is fixed to the ground surface, and the sediment can be pulled up and processed regularly; a gas injection device 15 is installed on the top of the oxygen injection tank 14, and the end of the gas injection pipe of the gas injection device 15 is inserted into the groundwater of the oxygen injection tank 14; and a multi-parameter tracking monitoring meter 10 is installed in the flocculation sedimentation zone 23 and the oxygen injection tank 14.

[0052] The working process of the oxygen injection permeable reaction wall system for groundwater in-situ remediation in this embodiment is as follows:

[0053] When the oxygen injection permeable reaction wall system is completed, the first water-facing surface water-blocking baffle is lifted to allow the contaminated groundwater to flow into the flocculation and sedimentation area 23 of the first permeable reaction wall 25. Under the action of the flocculant, the heavy metal ions form floccules and settle down under the action of gravity. When the multi-parameter tracking monitoring meter 10 in the flocculation and sedimentation area 23 monitors the water level to reach the original water level, the first water-facing surface water-blocking baffle 5 is closed. The multi-parameter tracking monitoring meter 10 in the flocculation and sedimentation area 23 reflects the concentration of pollutants in the groundwater in real time. When the concentration reaches the designed reduction concentration, the first water-facing surface water-blocking baffle 5 is slightly lifted to ensure that the upstream groundwater enters the flocculation and sedimentation area 23 at a certain stable flow rate.

[0054] Under the action of the water head pressure and the blocking of the inner waterproof baffle 8, the groundwater entering the flocculation and sedimentation area 23 will flow upward in front of the inner waterproof baffle 8, pass the inner waterproof baffle 8, and flow from top to bottom through the reagent filling area of ​​the first permeable reaction wall 25, first pass through the reaction filling 9, further react and precipitate to adsorb pollutants, and then through the sand and gravel filter material 7 to intercept the remaining colloidal suspended matter in the gaps of the filter material; after the residence time is satisfied, the first back-water waterproof baffle 13 is lifted up to allow the groundwater treated by the first permeable reaction wall 25 to flow into the oxygen injection tank 14 from the bottom;

[0055] The oxygen-containing air is sucked in by the gas injection device 15 and then injected downward into the groundwater, thereby changing the redox condition of the groundwater, increasing the dissolved oxygen in the groundwater, and providing an oxygen source for aerobic microorganisms; when the concentration of organic matter outside the pollution halo is moderate, it can provide a carbon source for the growth and reproduction of microorganisms without poisoning the microorganisms. Adequate carbon and oxygen sources can effectively promote the degradation of organic pollutants by aerobic microorganisms;

[0056] The multi-parameter tracking monitor 10 in the oxygen injection tank 14 reflects the dissolved oxygen content in the groundwater in real time; when the oxygen injection amount in the oxygen injection tank 14 reaches the design requirement and satisfies the required reaction time, the second water-facing surface water-blocking baffle 16 is lifted to allow the groundwater that has undergone sedimentation, reaction, adsorption, filtration, aeration and oxidation to enter the final second permeable reaction wall 26, and the activated carbon filter material 17 in the second permeable reaction wall 26 utilizes its porous medium characteristics to finally remove odor, colloids, organic matter and heavy metals in the water;

[0057] Finally, the second backwater baffle 19 is opened to discharge the treated groundwater downstream. A multi-parameter tracking monitoring meter 10 can be set downstream to monitor and reflect the treatment effect of the oxygen injection permeable reaction wall system of this embodiment in real time.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An oxygen-injected permeable reactive wall system for in-situ groundwater remediation, characterized in that: It comprises an underground reaction tank, wherein the water-facing end and the water-receiving end of the underground reaction tank are respectively provided with a water-facing surface half-enclosed slot and a water-receiving surface half-enclosed slot, a first permeable reaction wall is vertically slidably installed in the water-facing surface half-enclosed slot, a second permeable reaction wall is vertically slidably installed in the water-receiving surface half-enclosed slot, an oxygen injection tank is arranged between the first permeable reaction wall and the second permeable reaction wall, and a gas injection device for injecting oxygen into the groundwater in the oxygen injection tank is arranged on the top of the oxygen injection tank.

2. The oxygen-injected permeable reactive wall system for in-situ groundwater remediation according to claim 1, characterized in that: The water-facing side and the water-receiving side of the first permeable reaction wall are respectively provided with a first water-facing surface water-blocking baffle and a first water-receiving surface water-blocking baffle, and the first water-facing surface water-blocking baffle and the first water-receiving surface water-blocking baffle are respectively vertically slidably installed on the water-facing surface half-enclosed groove.

3. The oxygen-injected permeable reactive wall system for in-situ groundwater remediation according to claim 1, characterized in that: The water-facing side and the water-receiving side of the second permeable reaction wall are respectively provided with a second water-facing surface water-blocking baffle and a second water-receiving surface water-blocking baffle. The second water-facing surface water-blocking baffle and the second water-receiving surface water-blocking baffle are respectively vertically slidably installed on the water-receiving surface half-enclosed slot.

4. The oxygen-injected permeable reactive wall system for in-situ groundwater remediation according to claim 2 or 3, characterized in that: The bottom of the underground reaction tank penetrates into the relative waterproof layer by at least 1m, and the bottom ends of the waterproof baffle plate on the water-facing surface and the waterproof baffle plate on the water-receiving surface can extend below the bottom surface of the underground reaction tank.

5. The oxygen-injected permeable reactive wall system for in-situ groundwater remediation according to claim 1, characterized in that: The half-enclosed card slot on the water-facing side and the half-enclosed card slot on the water-receiving side are both U-shaped structures, and the openings are arranged opposite to each other; the side walls of the half-enclosed card slot on the water-facing side and the half-enclosed card slot on the water-receiving side that are perpendicular to the flow direction of groundwater are both provided with water permeable holes.

6. The oxygen-injected permeable reactive wall system for in-situ groundwater remediation according to claim 1, characterized in that: An inserted water-blocking baffle is arranged in the first permeable reaction wall, the water-facing side of the inserted water-blocking baffle is a flocculation sedimentation zone, and a flocculant dosing device for adding flocculant into the flocculation sedimentation zone is arranged on the top of the flocculation sedimentation zone.

7. The oxygen-injected permeable reactive wall system for in-situ groundwater remediation according to claim 6, characterized in that: The top end of the inserted water-blocking baffle is flush with the existing groundwater level, and the bottom end extends below the bottom surface of the underground reaction tank.

8. The oxygen-injected permeable reactive wall system for in-situ groundwater remediation according to claim 6, characterized in that: The backwater side of the inserted water-blocking baffle is a reaction zone, and the reaction zone is provided with a first gabion stone cage slidably connected to the half-enclosed groove on the water-facing surface, the bottom of the first gabion stone cage is filled with sand and gravel filter material, the top of the first gabion stone cage is filled with reaction filler, and the bottom of the reaction filler is located below the top surface of the inserted water-blocking baffle.

9. The oxygen-injected permeable reactive wall system for in-situ groundwater remediation according to claim 6, characterized in that: The top of the flocculation and sedimentation zone and the top of the oxygen injection tank are both installed with stainless steel lattices, and the flocculation and sedimentation zone and the oxygen injection tank are both provided with multi-parameter tracking monitoring meters.

10. The oxygen-injected permeable reactive wall system for in-situ groundwater remediation according to claim 1, characterized in that: The second permeable reaction wall comprises a second gabion stone cage slidably connected to the half-wrapped groove on the back water surface, and the second gabion stone cage is filled with activated carbon filter material.

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