Equipment and method for repairing underground water pollution in electroplating industrial park

Abstract

The invention discloses an electroplating industrial park groundwater pollution remediation device and method, and belongs to the technical field of groundwater remediation, the device comprises a permeable wall, a base arranged at the bottom end of the permeable wall, retention walls arranged on the two sides of the permeable wall, and a reaction box arranged in the permeable wall; cover plates are arranged at the top ends of the permeable walls; a positioning rod movably clamped with the retention wall is arranged on the base; the reaction box is filled with a reaction medium, and a sealing cover is arranged at the top end; the equipment disclosed by the invention is reasonable in structural design, and through the arrangement of the permeable wall, the base, the retention wall and the reaction box which can be flexibly assembled, the installation difficulty of the equipment is reduced, and the installation convenience of the equipment is improved; meanwhile, the reaction box is movably mounted in the permeable wall, so that a reaction medium in the reaction box can be conveniently replaced, the maintenance convenience of the equipment is improved, and the equipment is suitable for popularization and application.

Description

Technical Field

[0001] The present invention relates to the technical field of groundwater remediation, and in particular to a groundwater pollution remediation device and method for an electroplating industrial park. Background Art

[0002] Chromium pollution mainly comes from the discharge of industrial wastewater and solid waste from chromium salt production, electroplating, leather making, etc., and it is of great practical significance to carry out remediation of groundwater Cr(VI) pollution.

[0003] Permeable Reactive Grid (PRB) technology is an in-situ remediation technology for groundwater pollution that emerged in the 1990s. This technology combines three remediation mechanisms: physical, chemical, and biological. Pollutants are removed from groundwater through adsorption, precipitation, filtration, and biodegradation with the reaction medium.

[0004] In the prior art, PRB systems mostly adopt an integrated structure, which is difficult to construct and inconvenient for later maintenance. After the PRB is placed underground, the upper layer is covered with a cushion layer such as soil. When the reaction medium filled in the PRB system needs to be replaced, the PRB system needs to be dug out again, which is labor-intensive. Moreover, since the thickness of the PRB system is fixed, when the Cr(VI) in the groundwater is high, it will affect the repair effect of the PRB system. Summary of the invention

[0005] In response to the above-mentioned technical problems, the present invention provides a groundwater pollution remediation device and method for an electroplating industrial park.

[0006] The technical scheme of the present invention is: a groundwater pollution remediation device for an electroplating industrial park, comprising a permeable wall, a base arranged at the bottom of the permeable wall, water retaining walls obliquely arranged on both sides of the permeable wall and connected to the base, and a plurality of reaction boxes arranged in parallel up and down inside the permeable wall, wherein an obtuse angle is formed between the two water retaining walls and the permeable wall; a first cavity is arranged on both the front and rear sides of the permeable wall, and a second cavity is arranged inside the permeable wall and between the two first cavities; both the two first cavities can be connected to the second cavity; first plug-in slots are arranged on both the left and right sides of the permeable wall, and a second plug-in slot is arranged at the bottom; a cover plate is arranged at the top of the permeable wall; A first plug block capable of being movably connected to the second plug slot is arranged at the center of the upper end surface of the base, and a plurality of positioning rods are arranged on both sides of the upper end surface of the base; The two water retaining walls are respectively movably connected with the two first plug-in grooves in a one-to-one correspondence through the second plug-in blocks, and the two water retaining walls are provided with positioning holes that can be movably connected with the positioning rods in a one-to-one correspondence; The reaction box is movably connected to the inside of the second cavity. The reaction box is provided with water inlet channels at upper positions of the side walls close to the two first cavities. The reaction box is filled with reaction medium and a sealing cover is provided at the top of the reaction box.

[0007] Furthermore, an adjusting groove is provided between the first cavity and the second cavity at the front side of the permeable wall, and a flow regulating plate is slidably connected inside the adjusting groove; a plurality of adjusting holes are evenly distributed on the flow regulating plate; a plurality of flow holes that can be connected to each adjusting hole one by one are evenly distributed at the connection between the adjusting groove and the second cavity; a hydraulic push rod connected to the flow regulating plate is provided inside the permeable wall; Description: When in use, according to the concentration of pollutants in the groundwater, the flow regulating plate is pushed up and down inside the regulating tank by the hydraulic push rod, so that the regulating holes and the flow holes are staggered with each other, which can adjust the flow of groundwater entering the reaction box, which is beneficial to improve the remediation effect of contaminated groundwater.

[0008] Furthermore, a water sample collection tube penetrating the cover plate is arranged inside the first cavity at the rear side of the infiltration wall, a plurality of sampling cavities are evenly distributed inside the water sample collection tube, sampling holes corresponding to each sampling cavity are arranged on the outer wall of the water sample collection tube, and suction tubes corresponding to each sampling cavity are arranged inside the water sample collection tube; Note: By setting up a water sample collection tube, it is convenient to collect the restored groundwater samples in real time; by setting up multiple sampling cavities at different heights inside the water sample collection tube, it is convenient to detect the restoration results of groundwater at different depths.

[0009] Further, both sides of the outer wall of each reaction box are provided with a water baffle plate that can be slidably engaged with the inner wall of the second cavity; the bottom end of the reaction box is provided with an annular groove, and the sealing cover is provided with an annular protrusion that can be movably engaged with the annular groove at the bottom end of the adjacent reaction box; Note: By setting up multiple reaction boxes, not only can the convenience of the equipment be improved during installation, but it can also prevent groundwater from concentrating at a certain position in the reaction box and flowing out, thereby improving the reliability of the equipment.

[0010] Furthermore, a plurality of baffles are evenly distributed inside each reaction box, each baffle is fixedly connected to the top or bottom of the reaction box, and each baffle is staggered up and down inside the reaction box; Description: By setting baffles inside the reaction box, groundwater enters the reaction box through the water inlet channel at the front end of the reaction box, passes through each baffle in turn, and flows out from the water inlet channel at the rear end of the reaction box, which is beneficial to prolong the contact time between groundwater and reaction medium, thereby helping to improve the remediation efficiency of contaminated groundwater.

[0011] Furthermore, an inner sleeve is movably provided inside the second cavity, and each reaction box is movably connected inside the inner sleeve; a countersunk hole is provided at the top of the inner sleeve, and a lifting ear is provided inside the countersunk hole; Note: By arranging an inner sleeve inside the second cavity, it is convenient to replace the reaction medium filled in the reaction box, thereby effectively extending the service life of the equipment and reducing the cost of groundwater remediation.

[0012] Furthermore, a barrier net is provided on the water inlet channel; Note: By setting a barrier net on the water inlet channel, it is possible to prevent impurities carried in the groundwater from clogging the inside of the reaction box and affecting the contact efficiency between the chromium-containing wastewater and the reaction medium.

[0013] Furthermore, the reaction box is made of a degradable material, such as PBAT material; Note: Using a reaction box made of degradable materials can avoid secondary pollution of soil and groundwater during the use of the equipment.

[0014] The present invention also provides a method for remediating groundwater pollution in an electroplating industrial park, based on the above-mentioned groundwater pollution remediation equipment in an electroplating industrial park, comprising the following steps: S1. Determine the installation location of the equipment according to the concentration and depth of pollutants in the groundwater; then excavate the foundation pit for equipment installation; S2, place the base at the bottom of the installation pit, and then plug and fix the infiltration wall with the first plug-in block on the base through the second plug-in slot at the bottom; flexibly connect the two retaining walls with the first plug-in slots on both sides of the infiltration wall through the second plug-in blocks on the side walls; at this time, the two retaining walls are respectively plugged into the positioning rods on both sides of the base; S3, respectively filling the two first cavities with crushed stone particles with a particle size of 30-45 mm, respectively filling the reaction medium into each reaction box, and placing each reaction box in turn into the second cavity, at this time, the annular groove and the annular protrusion between the two adjacent reaction boxes are mutually engaged, and finally the cover plate is engaged with the top of the permeable wall; wherein the reaction medium is nano zero-valent iron with a particle size of 15-55 nm; S4. Under the action of the retaining wall, the contaminated groundwater flows toward the infiltration wall, first through the first cavity on the front side of the infiltration wall, then enters the interior of the reaction box through the water inlet channel at the front end of each reaction box, and comes into contact with the nano zero-valent iron. The nano zero-valent iron is used to adsorb the heavy metal chromium in the groundwater and react chemically, reducing the hexavalent chromium to trivalent chromium with lower toxicity. The repaired groundwater flows out through the water inlet channel at the rear end of the reaction box, and is finally discharged through the first cavity on the rear side of the infiltration wall.

[0015] Compared with the prior art, the beneficial effects of the present invention are embodied in the following aspects: First, the device structure of the present invention is reasonably designed. By providing a permeable wall, a base, a retaining wall and a reaction box that can be flexibly assembled, the difficulty of installing the device is reduced and the convenience of installing the device is improved; Second, the device of the present invention provides different cavities inside the permeable wall, and fills the two first cavities with crushed stone particles with a buffering effect. The crushed stone particles can slow down the impact of groundwater flow on the reaction box inside the second cavity, thereby improving the reliability of the reaction box. Third, the present invention arranges a plurality of reaction boxes of different heights inside the permeable wall, which is conducive to prolonging the residence time of groundwater inside the reaction box, improving the contact efficiency between contaminated groundwater and nano zero-valent iron, thereby improving the removal effect of heavy metal chromium in contaminated groundwater. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a longitudinal sectional view of the apparatus of the present invention; Figure 2 is a front view of the device of the present invention; Figure 3 is a top view of the apparatus of the present invention; Figure 4 It is a structural schematic diagram of the permeable wall of the present invention; Figure 5 It is a structural schematic diagram of the base of the present invention; Figure 6 It is a schematic diagram of the connection between the reaction box and the permeable wall of the present invention; Figure 7 The present invention Figure 6 A local enlarged schematic diagram of the middle A; Figure 8 It is a structural schematic diagram of a reaction box of the present invention; Fig. 9 It is a schematic diagram of the connection between the flow regulating plate and the permeable wall of the present invention; Fig.10 It is a schematic structural diagram of the water sample collection tube of the present invention; Among them, 1-permeability wall, 10-first cavity, 11-second cavity, 12-first plug-in slot, 13-second plug-in slot, 14-cover plate, 15-adjustment slot, 16-inner sleeve, 160-sinking hole, 161-lifting ear, 2-base, 20-first plug-in block, 21-positioning rod, 3-water retaining wall, 30-second plug-in block, 31-positioning hole, 4-reaction box, 40-water inlet channel, 400-barrier net, 41-sealing cover, 42-water retaining plate, 43-annular groove, 44-annular protrusion, 45-baffle, 5-flow regulating plate, 50-adjustment hole, 51-flow hole, 52-hydraulic push rod, 6-water sample collection tube, 60-sampling cavity, 61-sampling hole, 62-suction tube. DETAILED DESCRIPTION

[0017] Example 1: Figure 1 , Figure 2 , Figure 4The device for remediating groundwater pollution in an electroplating industrial park shown in the figure comprises a permeable wall 1, a base 2 arranged at the bottom of the permeable wall 1, water retaining walls 3 obliquely arranged on both sides of the permeable wall 1 and connected to the base 2, and four reaction boxes 4 arranged in parallel up and down inside the permeable wall 1, wherein the angle formed between the two water retaining walls 3 and the permeable wall 1 is 135°; a first cavity 10 is arranged on both the front and rear sides of the permeable wall 1, and a second cavity 11 is arranged inside the permeable wall 1 and between the two first cavities 10; the two first cavities 10 can be connected to the second cavity 11; a first plug-in slot 12 is arranged on both the left and right sides of the permeable wall 1, and a second plug-in slot 13 is arranged at the bottom; a cover plate 14 is arranged on the top of the permeable wall 1; like Figure 5 As shown, a first plug block 20 capable of being movably engaged with the second plug slot 13 is provided at the center of the upper end surface of the base 2, and three positioning rods 21 are provided on both sides of the upper end surface of the base 2; like Figure 1 , Figure 3 As shown, the two water retaining walls 3 are respectively movably connected with the two first plug-in slots 12 in a one-to-one correspondence through the second plug-in blocks 30, and the two water retaining walls 3 are provided with positioning holes 31 that can be movably connected with the positioning rods 21 in a one-to-one correspondence; like Figure 1 , Figure 8 As shown, the reaction box 4 is movably connected to the inside of the second cavity 11, and a water inlet channel 40 is provided at the upper position of the side wall of the reaction box 4 close to the two first cavities 10. The reaction box 4 is filled with reaction medium, and a sealing cover 41 is provided on the top of the reaction box 4; the reaction box 4 is made of degradable material, such as PBAT material.

[0018] Example 2: This example describes a method for remediating groundwater pollution in an electroplating industrial park, based on an electroplating industrial park groundwater pollution remediation device in Example 1, comprising the following steps: S1. Determine the installation location of the equipment according to the concentration and depth of pollutants in the groundwater; then excavate the foundation pit for equipment installation; S2, place the base 2 at the bottom of the installation pit, and then plug and fix the infiltration wall 1 with the first plug block 20 on the base 2 through the second plug slot 13 at the bottom; flexibly connect the two water retaining walls 3 with the first plug slots 12 on both sides of the infiltration wall 1 through the second plug blocks 30 on the side walls; at this time, the two water retaining walls 3 are respectively plugged into the positioning rods 21 on both sides of the base 2; S3, respectively filling the two first cavities 10 with crushed stone particles with a particle size of 30-35 mm, filling the reaction box 4 with a reaction medium, and placing each reaction box 4 in turn into the second cavity 11, and finally clamping the cover plate 14 on the top of the permeable wall 1; wherein the reaction medium is nano zero-valent iron with a particle size of 15-30 nm; S4. The contaminated groundwater flows toward the infiltration wall 1 under the action of the retaining wall 3, first passes through the first cavity 10 on the front side of the infiltration wall 1, then enters the interior of the reaction box 4 through the water inlet channel 40 at the front end of the reaction box 4, and contacts with the nano zero-valent iron. The nano zero-valent iron is used to adsorb the heavy metal chromium in the groundwater and react chemically to reduce the hexavalent chromium to trivalent chromium with lower toxicity. The repaired groundwater flows out through the water inlet channel 40 at the rear end of the reaction box 4, and is finally discharged through the first cavity 10 on the rear side of the infiltration wall 1.

[0019] Embodiment 3: This embodiment differs from Embodiment 1 in that Fig. 9 As shown, an adjusting groove 15 is provided between the first cavity 10 and the second cavity 11 on the front side of the permeable wall 1, and a flow regulating plate 5 is slidably engaged inside the adjusting groove 15; a number of adjusting holes 50 are evenly distributed on the flow regulating plate 5; a number of flow holes 51 that can be respectively connected to each adjusting hole 50 in a one-to-one correspondence are evenly distributed at the connection between the adjusting groove 15 and the second cavity 11; a hydraulic push rod 52 connected to the flow regulating plate 5 is provided inside the permeable wall 1; the angle formed between the two retaining walls 3 and the permeable wall 1 is 155°; and five positioning rods 21 are provided on both sides of the upper end surface of the base 2.

[0020] Example 4: This example describes a method for remediating groundwater pollution in an electroplating industrial park, which is based on a device for remediating groundwater pollution in an electroplating industrial park according to Example 3. The difference from Example 2 is that: In step S3, the particle size of the crushed stone particles is 35-45 mm; the particle size of the nano zero-valent iron is 30-55 nm.

[0021] In step S4, the concentration of heavy metal chromium in the contaminated groundwater is detected, and the flow regulating plate 5 is pushed up and down in the regulating tank 15 by the hydraulic push rod 52, so that the regulating hole 50 and the flow hole 51 are staggered with each other, thereby regulating the flow of groundwater entering the reaction box 4.

[0022] Embodiment 5: This embodiment differs from Embodiment 3 in that Figure 3 , Fig.10 As shown, a water sample collection tube 6 penetrating the cover plate 14 is arranged inside the first cavity 10 at the rear side of the infiltration wall 1, and four sampling cavities 60 are evenly distributed inside the water sample collection tube 6. Sampling holes 61 corresponding to each sampling cavity 60 are arranged on the outer wall of the water sample collection tube 6, and suction tubes 62 corresponding to each sampling cavity 60 are arranged inside the water sample collection tube 6.

[0023] Example 6: This example describes a method for remediating groundwater pollution in an electroplating industrial park, which is based on an electroplating industrial park groundwater pollution remediation device according to Example 5. The difference from Example 4 is that it also includes step S5: S5. Collect groundwater samples from different sampling chambers 60 using the suction tube 62 and perform tests.

[0024] Embodiment 7: This embodiment is different from Embodiment 5 in that eight sampling cavities 60 are provided.

[0025] Embodiment 8: This embodiment differs from Embodiment 5 in that Figure 1 , Figure 6 , Figure 8 As shown, water baffles 42 capable of slidingly engaging with the inner wall of the second cavity 11 are provided on both sides of the outer wall of each reaction box 4; an annular groove 43 is provided at the bottom end of the reaction box 4, and an annular protrusion 44 capable of movably engaging with the annular groove 43 at the bottom end of the adjacent reaction box 4 is provided on the sealing cover 41; three baffles 45 are evenly distributed inside each reaction box 4, each baffle 45 is fixedly connected to the top or bottom of the reaction box 4, and each baffle 45 is staggeredly distributed up and down inside the reaction box 4; a barrier net 400 is provided on the water inlet channel 40.

[0026] Example 9: This example describes a method for remediating groundwater pollution in an electroplating industrial park, based on an electroplating industrial park groundwater pollution remediation device according to Example 8, which differs from Example 6 in that: In step S3, after each reaction box 4 is sequentially placed into the second cavity 11, the annular groove 43 and the annular protrusion 44 between two adjacent reaction boxes 4 are engaged with each other; In step S4, the contaminated groundwater enters the interior of the reaction box 4 through the water inlet channel 40 at the front end of each reaction box 4, passes through each baffle 45 in sequence, and contacts with the nano zero-valent iron.

[0027] Embodiment 10: This embodiment is different from Embodiment 8 in that seven reaction boxes 4 are provided, and five baffles 45 are provided inside each reaction box 4 .

[0028] Embodiment 11: This embodiment differs from Embodiment 8 in that Figure 6 , Figure 7 As shown, the second cavity 11 is movably sleeved with an inner sleeve 16 , and each reaction box 4 is movably clamped inside the inner sleeve 16 ; a countersunk hole 160 is provided at the top of the inner sleeve 16 , and a lifting ear 161 is provided inside the countersunk hole 160 .

[0029] Example 12: This example describes a method for remediating groundwater pollution in an electroplating industrial park, and is based on an electroplating industrial park groundwater pollution remediation device according to Example 11. The difference from Example 9 is that: In step S5 , when the nano zero-valent iron inside the reaction box 4 needs to be replaced, the inner sleeve 16 is lifted by an external lifting device, and each reaction box 4 is taken out from the inner sleeve 16 .

[0030] Example 13: This example is different from Example 1 in that the number of reaction boxes is 8.

[0031] It should be noted that the hydraulic push rod 52 used in the present invention adopts the existing technology, which is not particularly limited here. Those skilled in the art can select corresponding products according to actual needs.

Claims

1. A groundwater pollution remediation equipment for electroplating industrial park, characterized in that: The invention comprises a permeable wall (1), a base (2) arranged at the bottom end of the permeable wall (1), a water retaining wall (3) arranged obliquely on both sides of the permeable wall (1) and connected to the base (2), and a plurality of reaction boxes (4) arranged vertically and parallelly inside the permeable wall (1), wherein an obtuse angle is formed between the two water retaining walls (3) and the permeable wall (1); a first cavity (10) is arranged on both the front and rear sides inside the permeable wall (1), and a second cavity (11) is arranged inside the permeable wall (1) and between the two first cavities (10); the two first cavities (10) can be connected to the second cavity (11); a first plug-in slot (12) is arranged on both the left and right sides of the permeable wall (1), and a second plug-in slot (13) is arranged at the bottom end; and a cover plate (14) is arranged at the top end of the permeable wall (1); A first plug block (20) capable of being movably engaged with the second plug slot (13) is provided at the center of the upper end surface of the base (2), and a plurality of positioning rods (21) are provided on both sides of the upper end surface of the base (2); The two water retaining walls (3) are respectively movably plugged into the two first plugging slots (12) in a one-to-one correspondence via the second plugging blocks (30), and the two water retaining walls (3) are each provided with a positioning hole (31) that can be movably plugged into the positioning rod (21) in a one-to-one correspondence; The reaction box (4) is movably snap-fitted into the interior of the second cavity (11); a water inlet channel (40) is provided at an upper position of the side walls of the reaction box (4) close to the two first cavities (10); the interior of the reaction box (4) is filled with a reaction medium; and a sealing cover (41) is provided at the top of the reaction box (4).

2. The groundwater pollution remediation equipment for electroplating industrial park according to claim 1 is characterized in that: An adjusting groove (15) is provided between the first cavity (10) and the second cavity (11) at the front side of the permeable wall (1), and a flow regulating plate (5) is slidably engaged inside the adjusting groove (15); a plurality of adjusting holes (50) are evenly distributed on the flow regulating plate (5); a plurality of flow holes (51) are evenly distributed at the connection between the adjusting groove (15) and the second cavity (11), and can be respectively connected to the adjusting holes (50) in a one-to-one correspondence; and a hydraulic push rod (52) connected to the flow regulating plate (5) is provided inside the permeable wall (1).

3. The groundwater pollution remediation equipment for electroplating industrial park according to claim 1 is characterized in that: A water sample collection tube (6) penetrating the cover plate (14) is arranged inside the first cavity (10) at the rear side of the permeable wall (1), a plurality of sampling cavities (60) are evenly distributed inside the water sample collection tube (6), sampling holes (61) are arranged on the outer wall of the water sample collection tube (6) and are connected to each of the sampling cavities (60) in a one-to-one correspondence, and suction tubes (62) are arranged inside the water sample collection tube (6) and are connected to each of the sampling cavities (60) in a one-to-one correspondence.

4. The groundwater pollution remediation equipment for electroplating industrial park according to claim 1 is characterized in that: Both sides of the outer wall of each reaction box (4) are provided with a water baffle (42) capable of slidingly engaging with the inner wall of the second cavity (11); the bottom end of the reaction box (4) is provided with an annular groove (43), and the sealing cover (41) is provided with an annular protrusion (44) capable of movably engaging with the annular groove (43) at the bottom end of an adjacent reaction box (4).

5. The groundwater pollution remediation equipment for electroplating industrial park according to claim 4 is characterized in that: A plurality of baffles (45) are evenly distributed inside each of the reaction boxes (4), each of the baffles (45) is fixedly connected to the top or bottom of the reaction box (4), and each of the baffles (45) is staggeredly distributed up and down inside the reaction box (4).

6. The groundwater pollution remediation equipment for electroplating industrial park according to claim 4 is characterized in that: An inner sleeve (16) is movably provided inside the second cavity (11), and each reaction box (4) is movably clamped inside the inner sleeve (16); a countersunk hole (160) is provided at the top end of the inner sleeve (16), and a lifting ear (161) is provided inside the countersunk hole (160).

7. The groundwater pollution remediation equipment for electroplating industrial park according to claim 1 is characterized in that: A barrier net (400) is provided on the water inlet channel (40).

8. The groundwater pollution remediation equipment for electroplating industrial park according to claim 1 is characterized in that: The reaction box (4) is made of degradable material.

9. A method for remediating groundwater pollution in an electroplating industrial park, based on the groundwater pollution remediation equipment in an electroplating industrial park according to claim 5, characterized in that: The following steps are involved: S1. Determine the installation location of the equipment according to the concentration and depth of pollutants in the groundwater; then excavate the foundation pit for equipment installation; S2, placing the base (2) into the bottom of the installation pit, and then plugging and fixing the infiltration wall (1) with the first plugging block (20) on the base (2) through the second plugging groove (13) at the bottom end thereof; movably engaging the two water retaining walls (3) with the first plugging grooves (12) on both sides of the infiltration wall (1) through the second plugging blocks (30) on the side walls thereof; at this time, the two water retaining walls (3) are respectively plugged into the positioning rods (21) on both sides of the base (2); S3, respectively filling the two first chambers (10) with crushed stone particles with a particle size of 30 to 45 mm, respectively filling the reaction medium into each reaction box (4), and sequentially placing each reaction box (4) into the second chamber (11), at which time the annular groove (43) and the annular protrusion (44) between two adjacent reaction boxes (4) are mutually engaged, and finally the cover plate (14) is engaged with the top of the permeable wall (1); wherein the reaction medium is nano zero-valent iron with a particle size of 15 to 55 nm; S4. The contaminated groundwater flows toward the infiltration wall (1) under the action of the retaining wall (3), first passes through the first cavity (10) on the front side of the infiltration wall (1), then enters the interior of the reaction box (4) through the water inlet channel (40) at the front end of each reaction box (4), and contacts with the nano zero-valent iron. The nano zero-valent iron is used to adsorb the heavy metal chromium in the groundwater and cause a chemical reaction, thereby reducing the hexavalent chromium to trivalent chromium with lower toxicity. The repaired groundwater flows out through the water inlet channel (40) at the rear end of the reaction box (4), and is finally discharged through the first cavity (10) on the rear side of the infiltration wall (1).

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