A permeable reactive barrier and wastewater treatment system for composite mine pollution

Abstract

The application provides a permeable reaction wall for composite mine pollution and a wastewater treatment system, wherein the permeable reaction wall comprises a framework shell, a filter layer and alkaline fillers; the alkaline fillers are located in the framework shell, and the filter layer is located between the alkaline fillers and the framework shell; the framework shell comprises a two-way geogrid, and the filter layer comprises a geotextile screen; the framework shell comprises a main body part and end parts located at two ends of the main body part, and openings are arranged on the end parts. The permeable reaction wall containing the alkaline fillers can neutralize the acidic water generated by the pollution in the mine, reduce the pollution degree of the water in the mine, reduce the cost, and has a good pollution water treatment effect.

Description

Technical Field

[0001] This application relates to the field of mine pollution control technology, and in particular to a permeable reactive wall and wastewater treatment system for complex mine pollution. Background Technology

[0002] Sulfide minerals, such as pyrite, found in mine waste can oxidize under the influence of surrounding water and oxygen, forming highly acidic mine wastewater rich in heavy metals and sulfates. This acidic mine wastewater is extremely acidic and rich in heavy metal ions and sulfates, causing severe pollution to the soil and water environment surrounding the mining area.

[0003] A permeable reactive barrier (PRB) is an in-situ remediation technology that uses specific reactive media to remove pollutants from groundwater through physical, chemical, and biological degradation methods. Its principle is to transform pollutants in contaminated mining areas into environmentally acceptable forms, thereby achieving the goal of groundwater pollution control.

[0004] Existing permeable reactive barriers (PRBs) for complex mine pollution include continuous reaction zone PRBs, funnel gate PRBs, and conventional injection PRBs. Continuous reaction zone PRBs and conventional injection PRBs are expensive to build and operate, and are usually installed downstream, which can easily cause pollution to accumulate downstream and form secondary pollution. During use, acidic groundwater can corrode the funnel wall of funnel gate PRBs, resulting in poor performance. Summary of the Invention

[0005] In view of this, the purpose of this application is to propose a permeable reactive wall and wastewater treatment system for complex mine pollution, so as to solve the problems of high cost and poor performance of existing permeable reactive walls for treating mine pollution.

[0006] To achieve the above objectives, this application provides a permeable reactive barrier for complex mine pollution, comprising a structural shell, a filter layer, and an alkaline filler; the alkaline filler is located inside the structural shell, and the filter layer is located between the alkaline filler and the structural shell; the structural shell includes a bidirectional geogrid, and the filter layer includes a geotextile mesh;

[0007] The housing includes a main body and ends located at both ends of the main body, with openings provided at the ends.

[0008] Furthermore, the bidirectional geogrid is a polypropylene or polyethylene bidirectional geogrid.

[0009] Furthermore, the geotextile screen is a polypropylene or polyethylene geotextile screen.

[0010] Furthermore, the permeable reactive wall also includes an open-hole water distribution pipe located within the alkaline filler, with both ends of the open-hole water distribution pipe connected to openings at both ends of the outer shell of the structure, and multiple holes provided on its sidewall.

[0011] Furthermore, the diameter of the permeable reactive wall is 800–1500 mm.

[0012] Furthermore, the alkaline filler includes municipal solid waste incinerator slag and carbon source particles, wherein the carbon source particles include corn cob particles or corn kernels, and the carbon source particles account for 5-10%.

[0013] Furthermore, the plurality of holes are staggered on the side wall of the perforated water distribution pipe, and the distance between adjacent holes is 100-200mm.

[0014] Furthermore, the particle size of the alkaline filler is 2–6 mm.

[0015] This application also provides a wastewater treatment system for complex mine pollution, applied in a mine pollution area. The wastewater treatment system includes multiple permeable reactive walls and diversion channels as described above. The multiple permeable reactive walls are staggered in the mine pollution area, and the diversion channels are connected to the openings at the ends of the structural shell.

[0016] Furthermore, the cross-section of the guide channel is hexagonal, and it is filled with crushed stone.

[0017] As described above, this application provides a permeable reactive barrier and wastewater treatment system for complex mine pollution. The permeable reactive barrier includes alkaline filler, a filter layer enclosing the alkaline filler, and a structural shell. The alkaline filler can neutralize groundwater within the mine pollution area, treating the groundwater and preventing it from contaminating other uncontaminated groundwater. The filter layer allows water to pass through, but prevents the alkaline filler and other impurities from passing through. The filter layer protects the alkaline filler, preventing impurities from entering and reducing the contact area between the alkaline filler and the groundwater within the mine pollution area. Therefore, the filter layer enhances the effectiveness of the permeable reactive barrier. The structural shell ensures the shape of the permeable reactive barrier and does not affect the entry and exit of groundwater from the mine pollution area. The permeable reactive barrier provided by this application is low-cost, effective, and allows for waste utilization, making it suitable for widespread implementation. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram illustrating the function of a continuous reaction belt-type PRB.

[0020] Figure 2 This is a schematic diagram illustrating the function of a funnel-type guide gate PRB.

[0021] Figure 3 This is a schematic diagram illustrating the function of a conventional injected PRB.

[0022] Figure 4 This is a schematic diagram of the structure of a permeable reactive wall used for complex mine pollution according to an embodiment of this application;

[0023] Figure 5 This is a schematic diagram illustrating the effect range of a permeable reactive barrier used for complex mine pollution in an embodiment of this application.

[0024] Figure 6 This is a schematic diagram of the installation structure of a wastewater treatment system for complex mine pollution according to an embodiment of this application;

[0025] Figure 7 This is a line graph showing the pH value of the wastewater treatment system for complex mine pollution according to an embodiment of this application after 3 months of use;

[0026] Figure 8 This is a cross-sectional structural diagram of a wastewater treatment system for complex mine pollution, as described in an embodiment of this application.

[0027] In the diagram: 1. Permeable reactive wall; 11. Alkaline packing; 12. Filter layer; 13. Frame shell; 131. Opening; 14. Perforated water distribution pipe; 2. Flow channel. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0029] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0030] As described in the background section, mine waste contains sulfide minerals, such as pyrite, which, under the influence of surrounding water and oxygen, oxidize to form highly acidic mine wastewater rich in heavy metals and sulfates. This acidic mine wastewater is extremely acidic and rich in heavy metal ions and sulfates, causing severe pollution to the soil and water environment surrounding the mining area. As long as sulfides are present in the mine waste, acidic mine wastewater will continue to be generated; without effective treatment, it can persist for 20 years or even longer.

[0031] Acidic mine wastewater pollution is extremely serious, with similar problems existing in metal mines, coal mines, and other similar facilities. Due to the lack of effective control measures, the wastewater flows into other unpolluted areas, severely polluting the surrounding soil and water environment. Improper treatment and disposal of mining waste and its resulting acidic mine wastewater not only exacerbate engineering disasters, waste resources, and pollute the environment, but also cause serious harm to society, the economy, and the environment.

[0032] Permeable reactive barriers (PRBs) are in-situ remediation technologies that utilize specific reactive media to remove pollutants from groundwater through physical, chemical, and biodegradation methods. The principle is to transform pollutants in contaminated areas into environmentally acceptable forms, thereby achieving the goal of groundwater pollution control. PRBs can effectively remove various pollutants, including dissolved heavy metals, organic matter, inorganic anions, and radioactive substances. PRB technology boasts advantages such as low cost, no need for external power, sustainable in-situ treatment of multiple pollutants, no need for storage containers, high treatment efficiency, minimal environmental impact, and high cost-effectiveness, and has gradually replaced traditional extraction treatment technologies. Currently, in my country, research on PRB technology for soil and groundwater pollution control is largely concentrated in laboratory experiments, lacking technological reserves and engineering application experience.

[0033] Existing groundwater recharge (PRR) systems are installed downstream of groundwater flow in contaminated mining areas to intercept and treat polluted groundwater, transforming it into an environmentally acceptable range after passing through reactive materials. However, existing PRB systems do not alter the environmental characteristics of the contaminated mining area; they merely passively receive polluted groundwater, which is not conducive to source control of pollution and only addresses the symptoms, not the root cause.

[0034] For acidic mines, as long as mine waste exists, pollution is constantly being generated, resulting in a consistently high operating load and long service life for groundwater remediation systems (PRS). Therefore, relying solely on existing PRS technologies to treat groundwater contaminated by acidic mines is a lengthy process that cannot control pollution at its source, and the remediation approach is reactive. Currently, conventional PRS technologies include:

[0035] (1) Continuous reaction belt PRB (e.g.) Figure 1 (As shown)

[0036] Continuous reaction belt PRBs are expensive and are generally suitable for sites with small contaminated areas. The contaminated areas are usually unevenly distributed, making it difficult to determine the thickness of the PRB packing material.

[0037] (2) Funnel-type PRB (e.g.) Figure 2 (As shown)

[0038] The groundwater in acidic mines is acidic, which corrodes the conventional funnel wall of a funnel-guided gate PRB (Peripherally Reinforced Burglar) system. Therefore, the funnel wall requires high corrosion resistance, thus increasing costs. Furthermore, the funnel-guided gate PRB system significantly and irreversibly disrupts the groundwater flow field, hindering the overall ecological restoration of the mine.

[0039] (3) Conventional injectable PRB (such as...) Figure 3 (As shown)

[0040] Currently, injected PRB only intercepts pollution downstream, which is costly and can easily cause pollution to accumulate downstream, resulting in secondary pollution.

[0041] Therefore, the purpose of this application is to propose a permeable reactive wall and wastewater treatment system for complex mine pollution, so as to solve the problems of high cost and poor performance of existing permeable reactive walls for treating mine pollution.

[0042] The embodiments of this application are described in detail below with reference to the accompanying drawings. This application provides a permeable reactive barrier 1 for complex mine contamination, such as... Figure 4 As shown, it includes a structural shell 13, a filter layer 12, and an alkaline filler 11; the alkaline filler 11 is located inside the structural shell 13, and the filter layer 12 is located between the alkaline filler 11 and the structural shell 13; the structural shell 13 includes a bidirectional geogrid, and the filter layer 12 includes a geotextile screen;

[0043] The outer casing 13 includes a main body and ends located at both ends of the main body, with openings 131 provided on the ends.

[0044] The alkaline filler 11 can neutralize the polluted water in the contaminated mining area, improving the quality of the polluted water. The outer shell 13 is the outer shell structure of the permeable reactive wall 1, and the bidirectional geogrid is selected, which has good mechanical properties, serving as a supporting shell without affecting the entry and exit of polluted water in the contaminated mining area. The filter layer 12 is used to wrap the alkaline filler 11, protecting it and preventing impurities located in the contaminated mining area from entering the alkaline filler 11 and contacting it, thereby affecting the neutralization effect of the alkaline filler 11 and the polluted water in the contaminated mining area, ensuring the effectiveness of the permeable reactive wall 1. The geotextile filter constitutes the filter layer 12, which can achieve the function of the filter layer 12 while also being low-cost, reducing the cost of the permeable reactive wall 1. The use of the bidirectional geogrid for the outer shell 13 is also low-cost, reducing the cost of the permeable reactive wall 1.

[0045] In addition, the outer shell 13 includes a main body and end portions. The outer shell 13 is a cylindrical structure, the main body is cylindrical, and the end portions are the two end faces of the cylindrical structure. Each end face is provided with an opening 131. When using the permeable reactive wall 1, the permeable reactive wall 1 is placed vertically in the contaminated area of ​​the mine. The openings 131 on the two end faces of the outer shell 13 allow contaminated water near the permeable reactive wall 1 to enter the permeable reactive wall 1 through the openings 131, which facilitates the permeable reactive wall 1 to treat the contaminated water in the contaminated area of ​​the mine and prevents the contaminated water from overflowing and polluting other uncontaminated areas.

[0046] The permeable reactive wall 1 provided in this application for complex mine pollution has the characteristics of low cost and good performance. It can be distributed in the mine pollution area to directly remediate the mine pollution area, inhibit the generation of new acid mine pollution, control pollution from the source, and has the characteristics of short treatment cycle and good ecological performance.

[0047] In some embodiments, the bidirectional geogrid is a polypropylene or polyethylene bidirectional geogrid. Polypropylene or polyethylene bidirectional geogrids have good corrosion resistance. Using polypropylene or polyethylene bidirectional geogrids ensures that the permeable reactive wall 1 has good corrosion resistance during use, preventing the corrosive effect of polluted water in the mine pollution area on the bidirectional geogrid, thereby extending the service life of the permeable reactive wall 1.

[0048] In some embodiments, the geotextile is a polypropylene or polyethylene geotextile. During use, the permeable reactive wall 1 needs to enter the highly corrosive acidic mining area, where polluted water will pass through the filter layer 12 into the alkaline filler 11. Therefore, the filter layer 12 is preferably a polypropylene or polyethylene geotextile with good corrosion resistance, which can extend the service life of the filter layer 12, and thus extend the service life of the permeable reactive wall 1.

[0049] In some embodiments, the permeable reactive wall 1 further includes an open-ended water distribution pipe 14 located within the alkaline filler 11. Both ends of the open-ended water distribution pipe 14 are connected to openings 131 at both ends of the outer casing 13, and its sidewalls are provided with multiple holes. The connection between the open-ended water distribution pipe 14 and the openings 131 serves a certain guiding function, allowing polluted water from the contaminated mining area to flow into the permeable reactive wall 1, facilitating the treatment of the polluted water. Simultaneously, the open-ended water distribution pipe 14 also serves as a replenishment channel for sulfate-reducing bacteria solution, which has strong acidophilic properties, beneficial for treating polluted water from the contaminated mining area. When the neutralization effect of the permeable reactive wall 1 decreases due to prolonged use, the sulfate-reducing bacteria solution can be replenished through the openings 131 and the open-ended water distribution pipe 14.

[0050] In some embodiments, the diameter of the permeable reactive wall 1 is 800–1500 mm. The polluted water in the contaminated mining area is neutralized within the permeable reactive wall 1. Therefore, based on the working method and characteristics of the permeable reactive wall 1, to ensure its effectiveness, its diameter is set to 800–1500 mm, which guarantees its effectiveness while not wasting the alkaline filler 11. The specific diameter of the permeable reactive wall 1 can be reasonably adjusted according to the water flow conditions within the contaminated mining area.

[0051] In some embodiments, the alkaline filler 11 comprises municipal solid waste incinerator slag and carbon source particles, wherein the carbon source particles comprise corn cob particles or corn kernels, and the carbon source particles account for 5-10%. Using municipal solid waste incinerator slag and corn cob particles or corn kernels as the alkaline filler 11 eliminates the need for secondary treatment during use and prevents secondary pollution. It allows for environmental coexistence, reduces costs, and facilitates waste utilization.

[0052] Using the municipal solid waste incineration slag as part of the alkaline filler 11 allows for full resource utilization of the slag. It fully utilizes the CaO and CaCO3 chemicals in the slag to neutralize acidic mine wastewater, increasing the pH of polluted water in the mining area and promoting the growth of sulfate-reducing bacteria. The high stability of SiO2 in the slag provides a long-term stable framework for the alkaline filler 11. The iron content in the slag inhibits the growth of Cu in acidic mines. 2+ Toxicity to sulfate-reducing bacteria.

[0053] Using corn cob particles or corn kernels as part of the alkaline filler 11 allows them to serve as a carbon source for sulfate-reducing bacteria. The high content of low-molecular-weight organic matter in the corn cob particles or corn kernels provides a carbon source for the initial growth of sulfate-reducing bacteria. The high molecular weight organic matter in the corn cob particles or corn kernels provides a carbon source for the long-term growth of sulfate-reducing bacteria. Furthermore, the corn cob particles or corn kernels reduce the redox potential of the polluted water in the mine contaminated area, increasing the growth activity of sulfate-reducing bacteria and facilitating the neutralization effect of the permeable reactive barrier 1 on the polluted water in the mine contaminated area, thus ensuring the treatment effect.

[0054] Sodium lactate is the optimal carbon source for sulfate-reducing bacteria. However, sodium lactate dissolves in groundwater and is lost with the groundwater, causing a loss of carbon source for sulfate-reducing bacteria. In addition, sodium lactate is acidic and will reduce the neutralization capacity of the municipal solid waste slag. Therefore, based on the effect and characteristics of the use of corn cob particles or corn kernels, it is preferred that the total proportion of corn cob particles or corn kernels be 5-10% to ensure the neutralization effect of the alkaline filler 11 while improving the activity of sulfate-reducing bacteria.

[0055] In some embodiments, a plurality of holes are staggered on the sidewall of the perforated water distribution pipe 14, and the distance between adjacent holes is 100-200 mm. The plurality of holes are used to supply water; therefore, staggering the holes ensures uniform water flow. The distance between adjacent holes is set according to the amount of groundwater flow in the contaminated area where the permeable reactive wall 1 is located, and the distance is set within 100-200 mm to ensure the usability of the perforated water distribution pipe 14.

[0056] In some embodiments, the alkaline packing material 11 has a particle size of 2–6 mm. Preferably, the alkaline packing material 11 with a particle size of 6 mm or less has a high specific surface area, providing a larger growth environment for sulfate-reducing bacteria and improving the treatment capacity of the permeable reactive wall 1. Preferably, the alkaline packing material 11 with a particle size of 2 mm or more improves the anti-clogging performance of the permeable reactive wall 1. Setting the particle size of the alkaline packing material 11 to 2–6 mm increases the interaction area between the alkaline packing material 11 and the polluted water in the contaminated area of ​​the mine.

[0057] In addition, when using the municipal solid waste incineration slag as the alkaline filler, pretreatment of the slag is required. The pretreatment steps are as follows: slag particles of 2-6 mm are separated through a two-stage screening process; slag particles larger than 6 mm are crushed and then screened again to obtain slag particles of 2-6 mm. The screened slag constitutes over 80% of the original slag, resulting in high utilization. The slag has a pH of 10.49-11.52, is alkaline, and can neutralize the acidic groundwater in the contaminated mining area. After pretreatment, the average specific surface area of ​​the slag increases by 23% to 7.24 m². 2 / g can serve as a good biological carrier for sulfate-reducing bacteria, which is beneficial for the treatment of polluted water. The pretreated municipal solid waste incinerator ash has a leakage coefficient of 3.96–9.51 × 10⁻⁶. -3 The permeability coefficient is 2.14–5.98 × 10 cm / s. -2 The speed of cm / s is increased by an order of magnitude, resulting in better penetration and less clogging.

[0058] Specifically, the radius of influence of each of the described permeable reactive walls 1 is 3-5m, and the area of ​​influence is shaped like an acorn, such as... Figure 5 As shown, darker colors represent lower pH values, and lighter colors represent higher pH values. The effective range of each of the permeable reactive walls 1 is related to the soil porosity and groundwater flow velocity at the location where the permeable reactive wall 1 is used, being directly proportional to the groundwater flow velocity and inversely proportional to the soil porosity.

[0059] This application also provides a wastewater treatment system for complex mine pollution, applicable to areas contaminated by mining, such as... Figure 6 As shown, the wastewater treatment system includes multiple permeable reactive walls 1 and diversion channels 2 as described above. The permeable reactive walls 1 are staggered within the contaminated mining area. The diversion channels 2 are connected to the openings 131 at the ends of the outer shell 13 of the structure. The top of the diversion channel 2 protrudes from the outer surface of the contaminated mining area, while the bottom is buried within the contaminated area. This allows it to intercept and divert acidic wastewater generated by runoff from the outer surface of the contaminated mining area, preventing wastewater from flowing into uncontaminated areas and thus expanding the contaminated area. Connecting the diversion channels 2 to the openings 131 at the ends of the permeable reactive walls 1 allows the collected wastewater to be diverted into the permeable reactive walls 1, enabling the permeable reactive walls 1 to treat the wastewater and enhancing the treatment effect of the wastewater treatment system.

[0060] In addition, the multiple permeable reactive walls 1 are staggered within the contaminated mining area, enabling them to sequentially treat the contaminated water along the flow direction of the groundwater within the contaminated mining area until it reaches the downstream of the groundwater. This significantly improves the treatment effect of the contaminated water, avoids damage to other uncontaminated areas from the contaminated mining area, and protects the ecological environment.

[0061] In some embodiments, the cross-section of the guide channel 2 is hexagonal, and it is filled with gravel. By setting the cross-section of the guide channel 2 to hexagonal, under the same cross-sectional area, the hexagonal structure can significantly improve the guiding effect and flow velocity of the guide channel 2, allowing polluted water to flow into the guide channel 2 along the bends at the interface, preventing the outflow of polluted water. Furthermore, filling the guide channel 2 with gravel can filter the polluted water, preventing impurities from flowing into the perforated water distribution pipe 14 through the guide channel 2 and clogging the holes in the perforated water distribution pipe 14, thereby affecting the use of the perforated water distribution pipe 14 and consequently affecting the wastewater treatment of the permeable reactive wall 1.

[0062] In addition, crushed stone with a calcium carbonate content of less than 5% is preferred to avoid the crushed stone from breaking under the action of acidic polluted water, which would affect the filtration effect of the crushed stone. Therefore, crushed stone with a calcium carbonate content of less than 5% can improve the long-term stability of the guide channel 2.

[0063] Specifically, such as Figure 7 and Figure 8 As shown, three months after the wastewater treatment system was put into use, the pH values ​​within the influence range of the four rows of permeable reactive walls from upstream to downstream were measured. It can be seen that after the wastewater treatment system, the pH value of the polluted water downstream of the mine pollution area increased to the neutral range, and the acidic wastewater was effectively treated.

[0064] The following two specific examples illustrate the effectiveness of the wastewater treatment system.

[0065] Example 1:

[0066] Within copper mine A, copper ore is accompanied by a large amount of FeS. When FeS encounters water and oxygen, it forms acidic mine wastewater. This acidic wastewater then dissolves heavy metals such as cadmium, chromium, and arsenic from the mine, causing widespread environmental pollution. After using the aforementioned wastewater treatment system, the treated groundwater quality meets the Class IV environmental quality standard. The water quality changes one year after treatment are shown in Table 1.

[0067] Table 1A shows the water quality of the copper mine pollution area one year after remediation.

[0068]

[0069] Example 2:

[0070] Within the B gold mine, a large amount of FeS is present. When FeS encounters water and oxygen, it forms acidic mine wastewater. This acidic wastewater then dissolves heavy metals such as cadmium, chromium, and arsenic from the mine, causing widespread environmental pollution. After using the aforementioned wastewater treatment system, the treated groundwater quality meets the Class IV environmental quality standard. The water quality changes one year after treatment are shown in Table 2.

[0071] Table 2B: Water quality in gold mine pollution areas one year after remediation.

[0072]

[0073] As can be seen from the above two embodiments, the wastewater treatment system provided in this application can improve the pH value of groundwater in the polluted area of ​​the mine, effectively control heavy metals in the groundwater in the polluted area of ​​the acid mine, inhibit the generation of new pollution in the acid mine, control pollution from the source, have a short treatment cycle, and have good ecological benefits.

[0074] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0075] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A wastewater treatment system for complex mine pollution, applied in a mine pollution area, characterized in that, It includes multiple permeable reactive walls and diversion channels. The multiple permeable reactive walls are staggered in the contaminated area of ​​the mine. The diversion channels are connected to the openings at the ends of the outer shell of the structure. The top of the diversion channels protrudes from the outer surface of the contaminated area of ​​the mine, and the bottom is buried in the contaminated area of ​​the mine. The permeable reactive wall includes a structural shell, a filter layer, alkaline filler, and perforated water distribution pipes; the alkaline filler is located inside the structural shell, and the filter layer is located between the alkaline filler and the structural shell; the structural shell includes a bidirectional geogrid, and the filter layer includes a geotextile mesh; The outer casing of the structure includes a main body and end portions located at both ends of the main body, with openings provided at the end portions; The perforated water distribution pipe is located inside the alkaline filler, and both ends of the perforated water distribution pipe are respectively connected to the openings on both ends of the structural shell, and multiple holes are provided on its side wall. The alkaline filler includes municipal solid waste incinerator slag and carbon source particles, wherein the carbon source particles include corn cob particles or corn kernels, and the carbon source particles account for 5-10%.

2. The wastewater treatment system for complex mine pollution according to claim 1, characterized in that, The bidirectional geogrid is a polypropylene or polyethylene bidirectional geogrid.

3. The wastewater treatment system for complex mine pollution according to claim 1, characterized in that, The geotextile filter is a polypropylene or polyethylene geotextile filter.

4. A wastewater treatment system for complex mine pollution according to claim 1, characterized in that, The diameter of the permeable reactive wall is 800~1500mm.

5. A wastewater treatment system for complex mine pollution according to claim 1, characterized in that, The multiple holes are staggered on the side wall of the perforated water distribution pipe, and the distance between adjacent holes is 100~200mm.

6. A wastewater treatment system for complex mine pollution according to claim 1, characterized in that, The alkaline filler has a particle size of 2~6mm.

7. A wastewater treatment system for complex mine pollution according to claim 1, characterized in that, The cross-section of the guide channel is hexagonal, and it is filled with crushed stone.

Images