An in-situ restoration system and operation method for wastewater in abandoned tunnels in metal mines

Abstract

The present invention discloses an in-situ remediation system for abandoned tunnel sewage in metal mines. The main body of the system uses the abandoned tunnels and other spaces formed by underground mining to construct a filled permeable reaction grid reaction unit; the water outlet automatic control device used in the above-mentioned sewage in-situ remediation system includes a box body, a control box, a water quality analyzer and a water pump; the present invention also proposes an operation method of an in-situ remediation system for polluted groundwater in metal mines, including the following steps: S1, determination of grid construction space; S2, screening of reaction materials; S3, filling of reaction materials; S4, construction of retaining walls and connection of pipelines; S5, operation; S6, maintenance and overhaul. The abandoned tunnel sewage in-situ remediation system set by the present invention utilizes the existing contaminated groundwater confluence space of the mine to achieve efficient passive remediation of contaminated groundwater, effectively solve the problems of tunnel groundwater pollution and collapse, reduce sewage treatment costs, and reduce the risk of groundwater overflow.

Description

Technical Field

[0001] The present invention relates to the technical field of contaminated groundwater remediation, and in particular to an in-situ remediation system and an operation method for wastewater in abandoned tunnels in underground metal mines. Background Art

[0002] Metal mining is the foundation of my country's economic development. During the mining and closure stages of metal mines, underground mining produces a large number of abandoned tunnels, which are also the main confluence and runoff areas of underground polluted groundwater. As time goes by, acid mine water generated in tunnels and other spaces will accumulate and overflow and spread, causing groundwater pollution in adjacent aquifers, and even gushing out through mine caves or discharge points to pollute surface water.

[0003] In the existing mining production process, all the gushing water in the tunnel is directly collected and uniformly discharged to the ground sewage treatment station, and no in-situ treatment is carried out underground or rainwater and sewage are collected and disposed of separately, which increases the pumping and drainage load and the treatment pressure and cost of the above-ground sewage treatment station. In fact, in the path of groundwater flow, only the water that comes into contact with the ore vein and undergoes dissolution reaction will be polluted, while other groundwater that infiltrates into the mine through the surrounding rock cracks and fault zones is basically unpolluted. In addition, after the mine is closed, due to the lack of active human pumping and drainage measures, a large amount of contaminated groundwater will accumulate in the abandoned tunnels and goafs underground. Finally, due to the lack of medium support for the overlying rock strata in these spaces, safety risks such as stratum subsidence and collapse will occur over a long period of time. Therefore, abandoned tunnels in metal mines are the main source of groundwater contamination and safety risk. Adopting effective in-situ remediation technology in this area to achieve effective groundwater management will help reduce the pressure of underground wastewater management and the risk of safety hazards and achieve safe mine operation. Therefore, it is necessary to design an in-situ remediation system and operation method for contaminated groundwater in metal mines to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings existing in the prior art, and to propose an in-situ remediation system and operation method for sewage in abandoned underground tunnels of metal mines. By setting a filled permeable reaction grid, the contaminated groundwater confluence space formed by the existing abandoned underground tunnels of the mine is fully utilized without occupying the mine space. The filling material can realize passive remediation of contaminated groundwater, effectively solve the underground groundwater pollution problem and collapse risk, reduce the sewage treatment cost during mining, and reduce the risk of contaminated groundwater overflow after mine closure.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An in-situ remediation system for wastewater in abandoned tunnels in metal mines comprises a filled permeable reaction grid. The system body composed of the filled permeable reaction grid utilizes the abandoned tunnel space formed by underground mining, and in-situ fills the space with reaction materials to construct a permeable reaction grid reaction unit. A retaining wall is arranged at the end of the reaction unit. A first water outlet pipe, a guide pipe, a water level monitoring pipe and a backwashing pipe are arranged on the water retaining wall. The first water outlet pipe is connected to an online water quality monitoring device, and the first water outlet pipe is connected to a second water outlet pipe and the guide pipe through an electric three-way valve.

[0007] Preferably, the in-situ filling reaction material in the system should be a material with good reaction activity and mechanical strength.

[0008] Preferably, the water level monitoring pipe is used to monitor the amount of water accumulated in the filled permeable reaction grid, and the water quality online monitoring device is used to control the discharge of qualified water bodies and the return and restoration of unqualified water bodies;

[0009] The online water quality monitoring device used in the above-mentioned sewage in-situ remediation system includes a housing, a control box, a water quality analyzer and a water pump. Two sampling barrels are arranged in the housing. A water pump is connected to the water inlet end with a water pumping pipe, and two shunt pipes are connected to the water pumping pipe. A cleaning mechanism for cleaning scale in the sampling barrel is arranged in the housing. The cleaning mechanism includes a motor fixedly connected to the upper end of the sampling barrel, the output shaft of the motor is fixedly connected to a drive shaft, and the side wall of the drive shaft is fixedly connected to a scraper through a connecting rod. The sampling barrel is provided with a sewage pipe connected to its interior, and the housing is provided with a blocking mechanism for blocking large particles of impurities from entering the sampling barrel.

[0010] Preferably, the blocking mechanism comprises two mounting cylinders and two protective cylinders fixedly connected to the side walls of the box body, the mounting cylinder is provided with a first filter screen, the protective cylinder is provided with a second filter screen, and the sampling cylinder is connected with a first connecting pipe and a second connecting pipe.

[0011] Preferably, the side wall of the sampling tube is rotatably connected to a rotating rod, and the rotating rod and the side wall of the driving shaft are fixedly connected to two bevel gears, the two bevel gears are meshed with each other, the side wall of the rotating rod is fixedly connected to a first brush plate, and the side wall of the driving shaft is fixedly connected to a second brush plate, and the diversion pipe, the first connecting pipe, the second connecting pipe and the sewage pipe are all provided with solenoid valves.

[0012] Preferably, the guide pipe and the backwash pipe both extend back to the water inlet end of the grille, and water distribution holes are arranged at the front ends of the guide pipe and the backwash pipe.

[0013] A method for operating an in-situ remediation system for wastewater in abandoned tunnels in underground metal mines, using an in-situ remediation system for wastewater in abandoned tunnels in underground metal mines, comprising the following steps:

[0014] S1. Determination of the grid construction space: Sampling and monitoring of water quality and quantity in the tunnel space where existing groundwater seeps out of the mine, calculating the pollution flux based on the concentration and outflow of pollutants in the groundwater, determining the target area that needs to be repaired, and clarifying the space for the construction of the filled infiltration reaction grid and the lithology of the surrounding rocks.

[0015] S2. Screening of reaction materials: Based on the pollution characteristics of groundwater in the target area, the reaction materials are determined through literature research, indoor batch experiments, column experiments, and pilot experiments. The reaction materials should have good reaction activity and mechanical strength. The filling amount of the reaction material in the infiltration reaction grid is determined in combination with the service life of the remediation system design and the reaction capacity of the reaction material to pollutants.

[0016] S3. Reaction material filling: Under the condition that the accumulated wastewater in the tunnel space has been drained and does not affect the construction, the screened reaction materials are evenly filled in according to the designed dosage, so that the contaminated groundwater in the space can all flow through the reaction materials.

[0017] S4. Construction of retaining wall and connection of pipelines: A retaining wall composed of steel sheet piles or cement walls is constructed at the end of the infiltration reaction grid. The retaining wall is embedded in the surrounding rocks. The first water outlet pipe, diversion pipe, water level monitoring pipe and backwash pipe are arranged on the upper part of the water retaining wall. The first water outlet pipe is installed with an online water quality monitoring device, and is connected to the second water outlet pipe and the diversion pipe through an electric three-way valve. The diversion pipe extends back to the inside of the grid to redirect the discharged water to the water inlet at the front end of the reaction grid. The backwash pipe is located in the lower middle part of the retaining wall and is usually in a closed state.

[0018] S5. Operation: The filled infiltration reaction grid realizes passive operation. The contaminated groundwater that converges in the space automatically flows through the reaction material in the grid under the hydraulic gradient and reacts with it, and then flows out through the first outlet pipe set on the retaining wall. During the operation of the system, the monitoring and control system controls the opening of the three-way valve according to the online water quality monitoring data. When the monitored water quality meets the standard, the three-way valve opens to the second outlet pipe side and directly enters the underground water collection system through the second outlet pipe. When the monitored water quality does not meet the standard, the three-way valve opens to the guide pipe side and returns to the inside of the grid through the guide pipe to react with the reaction material again. The water level monitoring pipe monitors the amount of water accumulated in the infiltration reaction grid to control the amount of water discharged from the first outlet pipe.

[0019] S6. Maintenance and inspection: During the long-term operation of the system, when the water quality of the first outlet pipe does not meet the standard for a long time or the reaction grid is blocked, open the backwash pipe and use the backwash water pump to backwash the reaction grid to promote the activity of the reaction material and clear the pore space. When the reaction material in the system is completely inactivated and the contaminated groundwater cannot be repaired, the system needs to stop running and open the retaining wall to replace the reaction material.

[0020] The present invention has the following beneficial effects:

[0021] 1. This device is equipped with a filled permeable reaction grid, which makes full use of the contaminated groundwater confluence space formed by the existing abandoned underground tunnels, main veins, goafs, etc. in the mine, and constructs an in-situ filled permeable reaction grid system. It does not occupy the mine space, and the filling material forms a support effect on the overlying rock layer to prevent settlement and reduce safety risks such as collapse. On the other hand, it can be used as a filling reaction material to realize the passive repair of contaminated groundwater, effectively solve the groundwater pollution problem caused by the accumulation and overflow diffusion of acid mine water generated in goafs and tunnels, reduce the sewage treatment cost during mining, and reduce the risk of contaminated groundwater overflow after mine closure;

[0022] 2. The device is equipped with automatic control devices such as online real-time water quality monitoring and electric valves. When the water quality monitoring at the outlet does not meet the standard, the substandard water can be automatically discharged into the grille through the diversion pipe to achieve secondary treatment. The repair system is passively operated, and the normal operating state can be controlled only through online monitoring, with low energy consumption and no secondary pollution.

[0023] 3. This device is equipped with a backwash port. When the activity of the reaction material in the system decreases or becomes blocked in the later stage of operation, the grid can be backwashed to promote the activity of the reaction material and increase the permeability;

[0024] 4. The device is equipped with a cleaning mechanism. Through the setting of two sampling tubes, the scale in one sampling tube can be automatically cleaned when sampling in the other sampling tube, so as to avoid the scale blocking the sampling tube. No manual maintenance and cleaning is required, thereby improving the practicality of the device and ensuring the continuous sampling work;

[0025] 5. The device is provided with a blocking mechanism and a rotating rod. During the rotation of the driving shaft, the first brush plate and the second brush plate rotate to clean the impurities on the first filter screen and the second filter screen, thereby achieving the purpose of automatically clearing the first filter screen and the second filter screen, improving the automation of the device and also improving the utilization rate of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the side plan structure of the filled permeable reaction grid of the present invention;

[0027] Figure 2 It is a schematic diagram of the top plan structure of the filled permeable reaction grid of the present invention;

[0028] Figure 3 Isothermal adsorption fitting of lead ion removal in metal mines by the iron-based mineral composite reaction material filled in the permeable reaction grid of the present invention;

[0029] Figure 4 Isothermal adsorption fitting of cadmium ions removed from metal mines by the iron-based mineral composite reaction material filled in the permeable reaction grid of the present invention;

[0030] Figure 5 Isothermal adsorption fitting of the iron-based mineral composite reaction material filled in the permeable reaction grid of the present invention for the removal of aluminum ions in metal mines;

[0031] Figure 6 Isothermal adsorption fitting of nickel ions removed from metal mines by the iron-based mineral composite reaction material filled in the permeable reaction grid of the present invention;

[0032] Figure 7 Schematic diagram of a column experiment for removing As3+ from the reaction material of the present invention;

[0033] Figure 8 This is a graph showing the test results of the reaction material of the present invention removing As3+;

[0034] Fig. 9 It is a schematic diagram of a test of the present invention;

[0035] Fig.10 It is a schematic structural diagram of the water quality online monitoring device of the present invention;

[0036] Fig.11 for Fig.10 A magnified view of the structure at A.

[0037] In the figure: 1 rainfall infiltration, 2 water seepage fissures, 3 surrounding rock, 4 mineral veins, 5 contaminated groundwater, 6 filled permeable reaction grid, 7 retaining wall, 8 first outlet pipe, 9 water quality online monitoring device, 10 electric three-way valve, 11 second outlet pipe, 12 diversion pipe, 13 backwash pipe, 14 water level monitoring pipe, 15 space between blocked tunnel and main tunnel, 16 outlet, 17 permeable reaction grid simulation tank, 18 reaction material filling area, 19 water collection tank outlet, 20 water collection tank body, 21 blocked tunnel contaminated groundwater confluence, 22 liquid storage container, 23 nitrogen bag, 24 peristaltic pump, 25 liquid sampling tube, 26 monitoring probe, 27 medium sampling port, 28 reaction material, 29 box, 30 control box, 31 water quality analyzer, 32 water pump, 33 sampling cylinder, 34 bevel gear, 35 installation cylinder, 36 motor, 37 first filter screen, 38 diversion pipe, 39 first brush plate, 40 first connecting pipe, 41 rotating rod, 42 driving shaft, 43 scraper, 44 second connecting pipe, 45 protective cylinder, 46 second filter screen, 47 second brush plate, 48 sewage pipe. DETAILED DESCRIPTION

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0039] An in-situ remediation system for polluted groundwater in a metal mine underground includes a filled permeable reactive barrier 6. The system main body composed of the filled permeable reactive barrier 6 utilizes the abandoned roadways and goaf spaces formed by underground mining, and in-situ fills reaction materials 28 therein to construct a permeable reactive barrier reaction unit. A water retaining wall 7 is arranged at the end of the reaction unit. A first water outlet pipe 8, a diversion pipe 12, a water level monitoring pipe 14 and a backwashing pipe 13 are arranged on the water retaining wall 7. The first water outlet pipe 8 is connected with an on-line water quality monitoring device 9. The first water outlet pipe 8 is connected to the second water outlet pipe 11 and the diversion pipe 12 through an electric three-way valve 10.

[0040] The reaction materials 28 in-situ filled in the system should be materials with good reaction activity and mechanical strength. The reaction materials 28 filled in the filled permeable reactive barrier 6 are granular materials with a certain mechanical strength, good water permeability and a large reaction capacity for heavy metal ions; the reaction materials 28 are preferably composed of carbonate rock materials that can effectively reduce the pH value of acidic wastewater and iron-based materials that can effectively remove various heavy metal ions, including sponge iron, iron oxide, zeolite-supported iron oxide, activated carbon-supported nano-iron, etc. When filling the materials, they can be compounded and loaded according to the characteristics of groundwater pollution to achieve the maximum removal effect. The reaction materials 28 used include carbonate rock and iron-based materials (zeolite-supported iron, activated carbon-supported iron, etc.); the above materials not only have a certain mechanical strength but also are easy to be processed into granular shapes. Carbonate rock can buffer the pH value of the aqueous solution and is used to adjust the pH value of acidic groundwater; iron-based materials can remove various heavy metal ions through adsorption, reduction, precipitation and other effects and are used for the fixed removal of heavy metals in polluted groundwater 5. For wastewater with a strong acidity (pH < 5), the method of filling carbonate rock at the front end and iron-based materials at the back end can be adopted. First, use carbonate rock to buffer the pH to above 6, and then use iron-based zeolite to remove heavy metal ions; for weakly acidic (5 < pH < 6.5), the filling amount of carbonate rock can be reduced or it can be directly mixed and filled with iron-based zeolite; for neutral and alkaline wastewater (pH > 7), iron-based zeolite can be directly used for filling;

[0041] Highly active granular materials with a certain mechanical strength are filled in the barrier. On the one hand, they act as filling materials to support the overlying rock formation and prevent collapse. On the other hand, they act as highly efficient reaction materials 28 to achieve the passive remediation of polluted groundwater 5.

[0042] The retaining wall 7 is constructed of steel sheet piles or cement walls and embedded in the surrounding rock 3 to store groundwater in the space. A sealed tunnel contaminated groundwater confluence port 21 constructed of steel sheet piles or cement walls is provided at the end of the filled permeable reaction grid 6, so that a certain amount of wastewater accumulated in the space can fully react with the reaction material 28 and then be discharged through the sealed tunnel contaminated groundwater confluence port 21.

[0043] The water level monitoring pipe 14 is used to monitor the amount of water accumulated in the filled permeable reaction grid 6. The guide pipe 12 and the backwash pipe 13 are both extended back to the water inlet end of the grid. The front ends of the guide pipe 12 and the backwash pipe 13 are provided with water distribution holes. The water quality online monitoring device 9 and the electric three-way valve 10 are controlled by the monitoring control system. The monitoring control system controls the electric three-way valve 10 to open to the second water outlet pipe 11 or the guide pipe 12 according to the data of the automatic online monitoring device. The water quality online monitoring device 9 is used to control the discharge of qualified water bodies and the return and repair of unqualified water bodies;

[0044] The water quality online monitoring device 9 used in the above-mentioned sewage in-situ remediation system includes a box 29, a control box 30, a water quality analyzer 31 and a water pump 32. The control box 30 and the water quality analyzer 31 are existing technologies and are not described in detail. A monitoring control system is provided in the control box 30, two sampling barrels 33 are provided in the box 29, and a water pump 32 is connected to the water inlet end. Two shunt pipes 38 are connected on the water pump 32. A cleaning mechanism for cleaning scale in the sampling barrel 33 is provided in the box 29, and the cleaning mechanism includes a motor 36 fixedly connected to the upper end of the sampling barrel 33, and the output shaft of the motor 36 is fixedly connected to the drive shaft 42. The side wall of the drive shaft 42 is fixedly connected to the scraper 43 through a connecting rod, and the sampling barrel 33 is provided with a sewage pipe 48 connected to its interior.

[0045] The box body 29 is provided with a blocking mechanism for blocking large particles of impurities from entering the sampling tube 33. The blocking mechanism includes two mounting tubes 35 and two protective tubes 45 fixedly connected to the side walls of the box body 29. The mounting tubes 35 are provided with a first filter screen 37, and the protective tubes 45 are provided with a second filter screen 46. The sampling tube 33 is connected with a first connecting pipe 40 and a second connecting pipe 44.

[0046] The side wall of the sampling tube 33 is rotatably connected to a rotating rod 41, and the rotating rod 41 and the side wall of the driving shaft 42 are fixedly connected to two bevel gears 34, and the two bevel gears 34 are meshed with each other. The side wall of the rotating rod 41 is fixedly connected to a first brush plate 39, and the side wall of the driving shaft 42 is fixedly connected to a second brush plate 47. Solenoid valves are provided on the shunt pipe 38, the first connecting pipe 40, the second connecting pipe 44 and the sewage pipe 48.

[0047] A method for operating an in-situ remediation system for polluted groundwater in a metal mine, using an in-situ remediation system for wastewater in an abandoned tunnel in a metal mine as described in any one of claims 1 to 4 above, comprising the following steps:

[0048] S1. Determination of grid construction space: Sampling and monitoring of water quality and quantity in tunnels and goafs where groundwater seeps out of the mine, calculating the pollution flux based on the concentration and outflow of pollutants in the groundwater, determining the target area that needs to be repaired, and clarifying the spatial conditions for the construction of the filled permeable reaction grid 6 and the lithology of the surrounding rock 3.

[0049] S2. Screening of reaction material 28: Based on the pollution characteristics of groundwater in the target area, the reaction material 28 is determined through literature research, indoor batch experiments, column experiments, and pilot experiments. The reaction material 28 should have both reaction activity and mechanical strength. The filling amount of the reaction material 28 in the permeable reaction grid is determined in combination with the designed service life of the remediation system and the reaction capacity of the reaction material 28 to pollutants.

[0050] S3. Filling of reaction materials 28: During the dry season or when the accumulated wastewater in the tunnel space is drained and does not affect the construction, the screened reaction materials 28 are evenly filled in according to the designed amount, so that the contaminated groundwater 5 in the space can all flow through the reaction materials 28 (to ensure that the reaction materials 28 can fill the required repair space, permeable sacks and permeable troughs can be used to first load the reaction materials 28, and then they are stacked in batches from the inside to the outside of the space so that the space is filled with reaction materials 28).

[0051] S4. Construction of retaining wall 7 and connection of pipelines: A retaining wall 7 composed of steel sheet piles or cement walls is constructed at the end of the permeable reaction grid. The retaining wall 7 is embedded in the surrounding rock 3. A first water outlet pipe 8, a guide pipe 12, a water level monitoring pipe 14 and a backwash pipe 13 are arranged on the upper part of the retaining wall 7. An online water quality monitoring device 9 is installed on the first water outlet pipe 8, and is connected to the second water outlet pipe 11 and the guide pipe 12 through an electric three-way valve 10, wherein the guide pipe 12 extends back to the inside of the grid to redirect the discharged water to the water inlet at the front end of the reaction grid. The backwash pipe 13 is located in the lower middle part of the water retaining wall 7 and is usually in a closed state.

[0052] S5. Operation: The filled permeable reaction grid 6 can realize passive operation. The contaminated groundwater 5 that converges in the space automatically flows through the reaction material 28 in the grid under the hydraulic gradient and reacts with it, and then flows out through the first water outlet pipe 8 set on the retaining wall 7. During the operation of the system, the monitoring and control system controls the opening of the electric three-way valve 10 according to the online water quality monitoring data. When the monitored water quality meets the standard, the electric three-way valve 10 opens to the second water outlet pipe 11 side, and can directly enter the underground water collection system through the second water outlet pipe 11. When the monitored water quality does not meet the standard, the electric three-way valve 10 opens to the guide pipe 12 side, and is returned to the inside of the grid through the guide pipe 12 to react with the reaction material 28 again. The water level monitoring pipe 14 monitors the amount of water accumulated in the permeable reaction grid to control the amount of water discharged from the first water outlet pipe 8.

[0053] S6. Maintenance and overhaul: During the long-term operation of the system, when the water quality of the first outlet pipe 8 does not meet the standard for a long time or the reaction grid is blocked (the water output is reduced), the backwash pipe 13 is opened and the reaction grid is backwashed by a backwash water pump to promote the activity of the reaction material 28 and clear the pore space. When the reaction material in the system is completely inactivated and the contaminated groundwater 5 cannot be repaired, the system needs to stop running and the retaining wall 7 is opened to replace the reaction material 28.

[0054] In the present invention, Figure 1-2 As shown in the figure, during the mining and closure stages of metal mines, rainfall infiltration 1 and other processes penetrate downward through the seepage fissures 2 distributed in the surrounding rock 3 of the mine. When groundwater flows through the ore veins 4 and undergoes dissolution and filtration reactions, some pollutants such as heavy metal ions will be released, causing groundwater pollution. Polluted groundwater 5 will be concentrated in abandoned tunnels, veins and goafs underground, which are also the main confluence and runoff areas of underground groundwater. As time goes by, mine wastewater generated in goafs, tunnels, etc. will accumulate and overflow and spread, causing serious pollution of mine groundwater.

[0055] Figure 3-6 The isothermal adsorption fitting of the zeolite-loaded iron reaction material 28 filled in the permeable reaction grid for the removal of heavy metal ions in metal mines clearly shows that it has good universality for the removal of typical heavy metal ions, large reaction capacity and high removal efficiency;

[0056] Figure 7-8 To simulate the permeable reaction grid for anionic heavy metal As using column experiments 3+ In the column experiment, the peristaltic pump 24 is connected to the liquid storage container 22 and the reactor through a pipeline. The liquid storage container 22 is provided with a nitrogen bag 23. The reactor is provided with a liquid sampling tube 25, a monitoring probe 26 and a medium sampling port 27. The reactor is filled with a reaction material 28. It can be seen that in the inlet water As 3+When the concentration was as high as 2000 μg / L and the groundwater flow rate was 0.8 m / d, the As in the effluent of the reaction column was 3+ The concentration was always kept at a low level, with the maximum concentration being only 124 μg / L. 3+ The concentration remains stable. 3+ The removal rate has been above 94%;

[0057] Fig. 9 The figure is a schematic diagram of a pilot test of a filled permeable reaction grid 6 constructed in an underground tunnel of a gold mine in Guizhou. A contaminated groundwater confluence 21 of a blocked tunnel is constructed by steel sheet piles or cement walls. A retaining wall 7 is provided in the space 15 between the blocked tunnel and the main tunnel. The contaminated groundwater 5 flows out through the outlet 16 of the retaining wall 7. The pilot experiment is designed to construct a water collection tank body 20 downstream of the confluence. The water collection tank body 20 is provided with a water collection tank outlet 19. Four independent reaction material filling areas 18 are designed at the connection of the water collection tank body 20, which are permeable reaction grid simulation tanks 17 for filling different reaction materials or mixed reaction materials 28. The contaminated groundwater 5 flows through the permeable reaction grid simulation tank 17 and reacts with the materials filled therein to achieve the removal of pollutants. After screening the material with the best removal effect on the contaminated groundwater 5, the retaining wall 7 can be opened to fill the reaction material 28 into the abandoned tunnel to achieve safe filling of the abandoned tunnel and repair of the contaminated groundwater 5.

[0058] In the initial state, the lower end of the box body 29 is equipped with an external support frame so that the first connecting pipe 40 of the box body 29 is immersed in sewage.

[0059] When in use, only the solenoid valve on one of the shunt pipes 38 is opened, and the solenoid valves on the first connecting pipe 40 and the second connecting pipe 44 corresponding to the sampling tube 33 corresponding to the shunt pipe 38 are opened, and the sewage enters the sampling tube 33. The sewage is sent to the water quality analyzer 31 for analysis by starting the water pump 32. After the sampling tube 33 has been used for a period of time, a large amount of scale is formed on its inner wall. The solenoid valves on the shunt pipe 38, the first connecting pipe 40 and the second connecting pipe 44 corresponding to the sampling tube 33 can be closed. After starting the motor 36, the output shaft of the motor 36 drives the drive shaft 42 to rotate, and the drive shaft 42 drives the scraper 43 to rotate, thereby scraping off the scale in the sampling tube 33, opening the first connecting pipe 40 and the sewage pipe 48, and the scale flows out under the action of gravity, and then the relevant solenoid valves are closed. In the process, the scale in the sampling tube 33 is automatically cleaned, and no manual maintenance and cleaning is required, thereby improving the practicality of the device.

[0060] During the cleaning process, the electromagnetic valves of the corresponding shunt pipe 38, the first connecting pipe 40 and the second connecting pipe 44 on another sampling cylinder 33 can be opened, so that another sampling cylinder 33 can perform sampling work, thereby ensuring the continuous progress of the sampling work;

[0061] During the rotation of the driving shaft 42, the two bevel gears 34 are engaged to drive the rotating rod 41 to rotate, and the first brush plate 39 and the second brush plate 47 rotate, so that the impurities on the first filter screen 37 and the second filter screen 46 can be cleaned, thereby achieving the purpose of automatically clearing the first filter screen 37 and the second filter screen 46.

[0062] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and practical concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An in-situ remediation system for wastewater in abandoned tunnels in metal mines, comprising a filled permeable reaction grid (6), characterized in that: The main body of the system composed of the filled permeable reaction grid (6) utilizes the abandoned tunnel space formed by underground mining, in which the reaction material (28) is filled in situ to construct a permeable reaction grid reaction unit, a water retaining wall (7) is arranged at the end of the reaction unit, and a first water outlet pipe (8), a flow guide pipe (12), a water level monitoring pipe (14) and a backwash pipe (13) are arranged on the water retaining wall (7), the first water outlet pipe (8) is connected to an online water quality monitoring device (9), and the first water outlet pipe (8) is connected to the second water outlet pipe (11) and the flow guide pipe (12) through an electric three-way valve (10); The water level monitoring pipe (14) is used to monitor the amount of water accumulated in the filled permeable reaction grid (6), and the water quality online monitoring device (9) is used to control the discharge of water bodies that meet the standards and the return and restoration of water bodies that do not meet the standards; The water quality online monitoring device (9) used in the above-mentioned sewage in-situ remediation system comprises a housing (29), a control box (30), a water quality analyzer (31) and a water pump (32); two sampling barrels (33) are arranged in the housing (29); a water inlet end of the water pump (32) is connected to a water pumping pipe, and two shunt pipes (38) are connected to the water pumping pipe; a cleaning mechanism for cleaning scale in the sampling barrel (33) is arranged in the housing (29); the cleaning mechanism comprises a motor (36) fixedly connected to the upper end of the sampling barrel (33); the output shaft of the motor (36) is fixedly connected to a drive shaft (42); a scraper (43) is fixedly connected to the side wall of the drive shaft (42) via a connecting rod; a sewage discharge pipe (48) connected to the interior of the sampling barrel (33) is arranged on the housing (29); and a blocking mechanism for blocking large particles of impurities from entering the sampling barrel (33) is arranged on the housing (29); The sampling cylinder (33) is connected to a first connecting tube (40) and a second connecting tube (44). The side wall of the sampling cylinder (33) is rotatably connected to a rotating rod (41). The rotating rod (41) and the side wall of the driving shaft (42) are both fixedly connected to two bevel gears (34). The two bevel gears (34) are meshed with each other. The side wall of the rotating rod (41) is fixedly connected to a first brush plate (39). The side wall of the driving shaft (42) is fixedly connected to a second brush plate (47). Solenoid valves are provided on the shunt tube (38), the first connecting tube (40), the second connecting tube (44) and the sewage pipe (48).

2. The in-situ remediation system for abandoned underground tunnel sewage in a metal mine according to claim 1 is characterized in that: The in-situ filled reaction material (28) in the system should be a material with good reaction activity and mechanical strength.

3. The in-situ remediation system for abandoned underground tunnel sewage in a metal mine according to claim 1 is characterized in that: The blocking mechanism comprises two mounting cylinders (35) and two protective cylinders (45) fixedly connected to the side walls of the box body (29); a first filter screen (37) is provided on the mounting cylinder (35), and a second filter screen (46) is provided on the protective cylinder (45).

4. The in-situ remediation system for abandoned underground tunnel sewage in a metal mine according to claim 1 is characterized in that: The guide pipe (12) and the backwash pipe (13) both extend back to the water inlet end of the grille, and water distribution holes are arranged at the front ends of the guide pipe (12) and the backwash pipe (13).

5. An operating method of an in-situ remediation system for wastewater in abandoned tunnels in metal mines, using an in-situ remediation system for wastewater in abandoned tunnels in metal mines as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Determination of grid construction space: sampling and monitoring of water quality and quantity in the abandoned tunnel space where the existing groundwater seeps out of the mine, calculating the pollution flux based on the concentration and outflow of pollutants in the groundwater, determining the target area that needs to be repaired, and clarifying the spatial conditions for the construction of the filled permeable reaction grid (6) and the lithology of the surrounding rock (3); S2. Screening of reaction materials (28): Based on the pollution characteristics of groundwater in the target area, the reaction materials (28) are determined through literature research, indoor batch experiments, column experiments, and pilot experiments. The reaction materials (28) should have both reaction activity and mechanical strength. In addition, the filling amount of the reaction materials (28) in the filled permeable reaction grid is determined in combination with the designed service life of the remediation system and the reaction capacity of the reaction materials (28) to pollutants; S3, filling of reaction materials (28): During the dry season or when the accumulated wastewater in the tunnel space is drained and does not affect the construction, the selected reaction materials (28) are evenly filled in according to the designed amount, so that the contaminated groundwater (5) in the space flows completely through the reaction materials (28); S4, construction of a water retaining wall (7) and connection of pipelines: a water retaining wall (7) composed of a steel sheet pile or a cement wall is constructed at the end of the filled permeable reaction grid, the water retaining wall (7) is embedded in the surrounding rock (3), and a first water outlet pipe (8), a flow guide pipe (12), a water level monitoring pipe (14) and a backwash pipe (13) are arranged on the upper part of the water retaining wall (7); a water quality online monitoring device (9) is installed on the first water outlet pipe (8), and is connected to the second water outlet pipe (11) and the flow guide pipe (12) through an electric three-way valve (10), wherein the flow guide pipe (12) extends back into the filled permeable reaction grid to redirect the discharged water to the water inlet at the front end of the filled permeable reaction grid, and the backwash pipe (13) is located in the middle and lower part of the water retaining wall (7) and is usually in a closed state; S5, operation: the filled permeable reaction grid (6) realizes passive operation. The contaminated groundwater (5) that converges in the space automatically flows through the reaction material (28) in the filled permeable reaction grid under the hydraulic gradient and reacts with it, and then flows out through the first outlet pipe (8) set on the retaining wall (7). During the operation of the system, the monitoring and control system controls the opening of the electric three-way valve (10) according to the online water quality monitoring data. When the monitored water quality meets the standard, the electric three-way valve (10) opens to the second outlet pipe (11) side and directly enters the underground water collection system through the second outlet pipe (11). When the monitored water quality does not meet the standard, the electric three-way valve (10) opens to the guide pipe (12) side and flows back to the filled permeable reaction grid through the guide pipe (12) to react with the reaction material (28) again. The water level monitoring pipe (14) monitors the amount of water accumulated in the filled permeable reaction grid to control the amount of water discharged from the first outlet pipe (8); S6. Maintenance and overhaul: During the long-term operation of the system, when the water quality of the first outlet pipe (8) does not meet the standard for a long time or the filled permeable reaction grid is blocked, the backwash pipe (13) is opened and the filled permeable reaction grid is backwashed by a backwash water pump to promote the activity of the reaction material (28) and clear the pore space. When the reaction material in the system is completely inactivated and the contaminated groundwater (5) cannot be repaired, the system needs to be stopped and the retaining wall (7) is opened to replace the reaction material (28).

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