Device for synchronously removing multi-target pollutants of underground water

Abstract

The utility model discloses a device for synchronously removing multi-target pollutants of underground water, and relates to the technical field of underground water pollution remediation. The device for synchronously removing the underground water multi-target pollutants comprises a permeable reactive barrier, a first unit is arranged on the right side of the permeable reactive barrier, a permeable grid is arranged on the right side of the first unit, an automatic sample detection and analysis device is arranged above the permeable grid, and a second unit is arranged on the right side of the permeable grid. According to the device for synchronously removing the multi-target pollutants in the underground water, the pollutants are subjected to multi-stage enhanced treatment based on the synergistic effect of adsorption, electrochemistry, plant enrichment and microbial degradation through an electrodynamic force combined physical-chemical-phytoremediation technology, so that the efficient and lasting removal of the composite pollutants such as heavy metals, inorganic matters and organic matters in the underground water is realized; the method solves the problem of difficult cooperative treatment of multiple pollutants, and has the advantages of simple construction, low installation cost, efficient restoration, strong applicability, ecological environmental protection and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of groundwater pollution remediation, in particular to a device for synchronously removing multi-target pollutants in groundwater. Background Art

[0002] With the rapid development of economy and industry, the discharge of domestic sewage, industrial wastewater, and the leakage of leachate from solid waste have significantly increased the harmful substances in groundwater, such as heavy metals, bacteria, inorganic salts, organic matter, etc.

[0003] At present, groundwater pollution remediation technologies mainly include physical, chemical and biological technologies. Physical technologies include gas lift, air stripping, multiphase extraction, in-situ heat treatment, adsorption, electrodynamics and other methods; chemical technologies include redox, leaching, extraction treatment and other methods; biological technologies include plant and microbial methods. Phytoremediation is the process of using plants to absorb, stabilize and decompose pollutants in contaminated soil areas or groundwater. Microbial remediation is the degradation of pollutants in the soil through microbial enrichment and microbial transformation. The adsorption of the filling matrix of the phytoremediation belt, the assimilation and absorption of the plant and the degradation of the microorganism can remove pollutants such as nitrogen, phosphorus, heavy metals and organic matter in the water body. Due to the different composition, pollutant types and properties of underground water-containing media, especially in the case of complex pollution with the simultaneous presence of multiple pollutants, a single remediation technology has obvious shortcomings and it is difficult to achieve the remediation goal. The coupling of multiple technologies is one of the effective measures to solve the problem of complex pollution of soil and groundwater.

[0004] Permeable reactive wall (PRB), electrokinetic remediation (EKR) and phytoremediation are emerging in-situ remediation technologies for soil and groundwater. Permeable reactive wall is to intercept or remove pollutants in groundwater by filling specific active fillers in the wall through adsorption, precipitation, surface complexation, redox and biodegradation. It can effectively remove inorganic salts, highly toxic heavy metals such as cadmium, chromium and lead, and various pollutants such as vinyl chloride organic pollutants. The PRB method can treat a variety of pollutants for a long time and has little disturbance to groundwater. It has the advantages of no need for external power and simple construction. However, it is necessary to comprehensively consider factors such as pollutant characteristics, hydrogeological conditions, economic benefits, and environmental impact of on-site construction. Electrokinetic remediation is to install electrodes on the contaminated site and apply DC voltage to migrate pollutants to both sides of the electrodes to repair the pollution. The solubility of pollutants has a great influence on the treatment effect. When there are a large number of metal ions and negatively charged acid ions in the soil and groundwater, significant electromigration will occur. Electrokinetic remediation is not effective in removing pollutants with poor solubility and weak desorption ability and non-polar organic matter.

[0005] The combined application of electrodynamic remediation and other remediation technologies has received more and more attention. Among them, the permeable reaction wall-electrokinetic-plant (PRB-EKR-Phytoremediation) joint technology is becoming a research hotspot in the field of soil and groundwater environmental remediation at home and abroad. The permeable reaction wall-electrokinetic-plant joint remediation technology combines the advantages of each technology and comprehensively utilizes physical, chemical, electrochemical, biological and ecological effects to effectively improve the removal efficiency of pollutants and reduce the cost of remediation. The basic principle is to use PBR for primary pollution remediation to remove complex pollutants such as heavy metals, inorganic salts and organic pollutants; use electrodynamic-plant coupling technology for secondary pollution remediation. Under the action of electrodynamics, heavy metals, inorganic salts and organic pollutants move rapidly to both ends of the electrodes. During the movement, the filler matrix adsorbs, microorganisms degrade, and plants absorb and remove pollutants.

[0006] Existing technologies generally couple electrodynamic remediation with other single technologies such as permeable reaction walls and phytoremediation, mainly for the removal of single pollutants, or through traditional adsorption and plant absorption. How to achieve simultaneous and efficient removal of COD, nitrogen and phosphorus, heavy metals, inorganic salts, and organic matter in contaminated sites remains a huge challenge. So far, existing soil and groundwater remediation technologies cannot effectively treat complex pollutants. Utility Model Content

[0007] 1. Technical issues to be resolved

[0008] In view of the deficiencies of the prior art, the utility model provides a device for synchronously removing multiple target pollutants from groundwater, which solves the problems existing in the prior art.

[0009] (II) Technical solution

[0010] To achieve the above objectives, the utility model is implemented through the following technical solutions: a device for synchronously removing multi-target pollutants from groundwater, comprising a permeable reaction wall, a first unit is arranged on the right side of the permeable reaction wall, a permeable grille is arranged on the right side of the first unit, an automatic sample detection and analysis device is arranged above the permeable grille, a second unit is arranged on the right side of the permeable grille, a water-blocking wall and a grille filter are arranged on the right side of the second unit, the water-blocking wall is located below the grille filter, a plant remediation belt is arranged on the right side of the grille filter, a pool bottom is arranged at the bottom of the plant remediation belt, yin and yang electrodes are arranged in the plant remediation belt, a deep purification module is arranged on the right side of the plant remediation belt, the deep purification module includes a pool body, a bionic filler is arranged on the right side of the pool body, an outlet pool is arranged on the right side of the bionic filler, the outlet pool includes a pool body, and a pool bottom is arranged at the bottom of the pool body.

[0011] Preferably, the depth of the permeable reaction wall is greater than 1 m of the groundwater pollution plume depth, the distance between two adjacent walls is 2 to 5 m, a permeable grid is arranged in the middle of the wall to divide the reaction area into a first unit and a second unit, and the grid is welded into a hole-shaped grid by longitudinal and transverse steel bars, and the hole spacing is 2 to 5 cm.

[0012] Preferably, the first unit wall is composed of a steel frame and a permeable geotextile, and the steel frame is covered with the permeable geotextile. The steel frame is welded vertically and horizontally by multiple stainless steel solid pipes, with a pipe diameter of 12 to 20 mm and a frame width of 30 to 50 cm. The permeability coefficient of the permeable geotextile is greater than 5.0*10-5m / s.

[0013] Preferably, the second unit wall is composed of a waterproof partition wall and a grille filter. The top height of the partition wall is located in the middle of the first unit wall. A grille filter is installed on the top, and the grille hole size is 1 cm to 2 cm.

[0014] Preferably, the first unit is filled with an adsorption filler, which is one of iron ore, activated zeolite, volcanic rock, ceramsite or a composite filter material, with a particle size of 2 to 8 mm; the second unit is filled with an active filler, which is a biochar composite filler, and the filler is a spherical porous particle with a particle size of 2 to 4 mm. The material filling needs to make the permeability coefficient of the wall and the reaction zone 2 to 5 times higher than the permeability coefficient of the aquifer.

[0015] The biochar composite filler comprises 40% to 50% bentonite-modified biochar, 20% to 25% zero-valent iron, 10% to 15% clay, 7% to 15% diatomaceous earth, and 3% to 5% ammonium bicarbonate, wherein clay is used as a bonding raw material, diatomaceous earth is used as a high permeability raw material, and ammonium bicarbonate is used as a pore-forming agent. The bentonite-modified biochar is prepared by mixing montmorillonite bentonite and biochar and then pyrolyzing them after standing. The particle size of the montmorillonite bentonite is 0.05 to 0.1 mm, the particle size of the biochar is 0.15 to 0.18 mm, the mass ratio of bentonite to biochar is 1:8 to 20, the pyrolysis temperature is 500 to 800°C, and the pyrolysis time is 30 to 60 minutes.

[0016] Preferably, the bottom surfaces of the plant restoration zone pool body and the deep purification module pool bottom are impermeable walls, the bottom surfaces are flush with the top of the permeable reaction wall watertight wall, and the outlet side wall is composed of a steel frame and a permeable geotextile.

[0017] The plant restoration zone pool is filled with a matrix, which is one of gravel, sand, zeolite, anthracite, bioceramsite, manganese sand, steel slag, waste wood, corn cob particles or a composite filler, and plants are planted on the top of the matrix. The combination ratio of the plant restoration zone matrix needs to be selected according to the polluted water quality, compliance requirements, etc. The most economical ratio.

[0018] The particle size of the inorganic fillers such as gravel, sand, zeolite, etc. is 2-10 mm, and the particle size of the organic fillers such as waste wood blocks, corn cob particles, etc. is 3-6 mm.

[0019] Preferably, electric restoration cathode and anode electrodes are provided on both sides of the plant restoration pool body. Under the action of the DC electric field, charged heavy metals or polar organic pollutants in the soil move to the oppositely charged electrodes by electric migration, and are adsorbed by the matrix, absorbed by the plants, and decomposed and removed by microorganisms.

[0020] The cathode electrode and the anode electrode are any one of graphite rod, titanium, stainless steel, conductive metal organic framework material, iron or porous carbon material.

[0021] The low-voltage DC power supply is a solar photovoltaic device. When a DC voltage is applied to the electrodes, a DC electric field will be formed between the electrodes, and the voltage range for driving the electric repair is 0 to 50V.

[0022] Preferably, the deep purification module pool is filled with bionic materials as microbial carriers, which are one or both of polypropylene ball fillers or carbon fiber aquatic plants for microbial biofilm formation.

[0023] Preferably, the bottom of the outlet pool is flush with the bottom of the deep purification module pool, and the pool bottom is made of highly permeable material, which serves as a drainage layer to allow the purified water to quickly penetrate into the groundwater environment. The outlet side wall is composed of a steel frame and a permeable geotextile, and the pool size is 0.5 to 0.8 m;

[0024] The highly permeable material is a composite layer of pebbles and crushed stones, the particle size of the pebbles is 20 to 50 mm, the particle size of the crushed stones is 10 to 30 mm, and the thickness is 0.5 to 0.6 m;

[0025] The plant restoration belt is added with plant growth promoting bacteria (PGPB) to enhance the metal resistance of plants, promote the absorption of heavy metals and nutrients by plants, and thus improve the efficiency of plant restoration. The plants include wetland plants and heavy metal hyperaccumulators. Wetland plants include plants with strong sewage purification capabilities such as reeds, cattails, irises, loosestrife, lily, canna, etc. Heavy metal hyperaccumulators are extremely resistant to heavy metals such as Cr, Pb, Cu, and Cd, including one or more of dianthus acutus, coreopsis grandiflora, alfalfa, Li's grass, pokeweed, baoshan violet, cosmos, ryegrass, and centipede grass.

[0026] (III) Beneficial effects

[0027] The utility model provides a device for synchronously removing multiple target pollutants from groundwater.

[0028] Beneficial effects:

[0029] The device for simultaneous removal of multiple target pollutants in groundwater uses electrodynamics combined with physical-chemical-plant remediation technology to perform multi-stage enhanced treatment of pollutants based on the synergistic effects of adsorption-electrochemistry-plant enrichment-microbial degradation, achieving efficient and lasting removal of complex pollutants such as heavy metals, inorganic and organic matter in groundwater, solving the problem of difficult coordinated treatment of multiple pollutants. It has the advantages of simple construction, low installation cost, efficient remediation, strong applicability, and ecological and environmental protection.

[0030] The present invention realizes the integrated deep treatment of groundwater with complex pollution such as heavy metals, ammonia nitrogen, inorganic salts, and organic matter through the synergistic effect of permeable reaction walls, electrodynamic combined plant remediation, and deep purification modules, and multi-stage enhanced treatment, thereby expanding the application scope of electrodynamic-plant coupled remediation technology.

[0031] The electrodynamic-plant coupling remediation technology can speed up the flow of groundwater and pollutants. Heavy metals, cations and polar organic pollutants in the soil migrate to the cathode under the action of the DC electric field. The pollutants are adsorbed by the matrix, absorbed by the plants, and degraded by microorganisms. At the same time, the addition of plant growth-promoting bacteria and the slow release of carbon sources by the matrix stimulate the growth of microorganisms, which can significantly improve the efficiency of plant remediation and avoid secondary pollution.

[0032] The deep purification module is used to continuously degrade residual pollutants through microorganisms, thereby achieving efficient and lasting removal of groundwater pollutants. The PLC control system determines the type, dosage and time of adding microorganisms based on water quality monitoring information, realizing automated and intelligent operation, effectively improving the stability and utilization rate of high-efficiency degradation bacteria, and solving the problem of low pollutant removal rate.

[0033] The zero-valent iron in the biochar composite filler is used to reduce heavy metals and pollutants. The generated Fe2+ is absorbed by microorganisms and plants as nutrients and enhances their growth and metabolic capabilities, promoting the absorption and degradation of pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A cross-sectional view of a device for synchronously removing multiple target pollutants from groundwater according to an embodiment of the present application;

[0035] Figure 2 A plan view of a device for synchronously removing multiple target pollutants from groundwater according to an embodiment of the present application;

[0036] Figure 3 Schematic diagram of electrode arrangement according to an embodiment of the present application.

[0037] In the figure: 1. Permeable reaction wall; 11. Permeable grille; 12. First unit; 13. Second unit; 14. Water-blocking wall; 15. Grille filter; 16. Automatic sample detection and analysis device; 2. Plant restoration belt; 21. First tank body; 22. Cationic and anodic electrode pairs; 23. Bottom of tank body; 3. Deep purification module; 31. Second tank body; 32. Bionic filler; 4. Outlet pool; 41. Pool bottom. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0039] See also Figure 1-3 The utility model provides a technical solution: a device for synchronously removing multiple target pollutants from groundwater, comprising a permeable reaction wall 1, a first unit 12 is arranged on the right side of the permeable reaction wall 1, a permeable grille 11 is arranged on the right side of the first unit 12, an automatic sample detection and analysis device 16 is arranged above the permeable grille 11, a second unit 13 is arranged on the right side of the permeable grille 11, a water-blocking wall 14 and a grille filter 15 are arranged on the right side of the second unit 13, the water-blocking wall 14 is located on the grille filter 15 Below, a plant remediation belt 2 is arranged on the right side of the grille filter 15, a pool bottom surface 23 is arranged at the bottom of the plant remediation belt 2, a positive and negative electrodes 22 are arranged in the plant remediation belt 2, a deep purification module 3 is arranged on the right side of the plant remediation belt 2, and the deep purification module 3 includes a first pool body 21, a bionic filler 32 is arranged on the right side of the first pool body 21, an outlet pool 4 is arranged on the right side of the bionic filler 32, and the outlet pool 4 includes a second pool body 31, and a pool bottom 41 is arranged at the bottom of the second pool body 31.

[0040] The depth of the permeable reaction wall 1 is greater than the depth of the groundwater pollution plume by 1m, the distance between two adjacent walls is 2-5m, a permeable grid 11 is arranged in the middle of the wall to divide the reaction area into a first unit 12 and a second unit 13, the grid is welded into a hole-shaped grid by longitudinal and transverse steel bars, and the hole spacing is 2-5cm.

[0041] The wall of the first unit 12 is composed of a steel frame and a permeable geotextile, and the steel frame is covered with the permeable geotextile. The steel frame is welded vertically and horizontally by multiple stainless steel solid pipes, with a pipe diameter of 12-20 mm and a frame width of 30-50 cm. The permeability coefficient of the permeable geotextile is greater than 5.0*10-5m / s.

[0042] The wall of the second unit 13 is composed of a watertight water-blocking wall and a grille filter. The top of the water-blocking wall is located in the middle of the wall of the first unit. A grille filter is installed on the top. The size of the grille holes is 1 cm to 2 cm.

[0043] The first unit 12 is filled with an adsorption filler, which is one of iron ore, activated zeolite, volcanic rock, ceramsite or a composite filter material, with a particle size of 2 to 8 mm; the second unit 13 is filled with an active filler, which is a biochar composite filler, and the filler is a spherical porous particle with a particle size of 2 to 4 mm. The material filling needs to make the permeability coefficient of the wall and the reaction zone 2 to 5 times higher than the permeability coefficient of the aquifer.

[0044] The biochar composite filler comprises 40% to 50% bentonite-modified biochar, 20% to 25% zero-valent iron, 10% to 15% clay, 7% to 15% diatomaceous earth, and 3% to 5% ammonium bicarbonate, wherein clay is used as a bonding raw material, diatomaceous earth is used as a high permeability raw material, and ammonium bicarbonate is used as a pore-forming agent. The bentonite-modified biochar is prepared by mixing montmorillonite bentonite and biochar and then pyrolyzing them after standing. The particle size of the montmorillonite bentonite is 0.05 to 0.1 mm, the particle size of the biochar is 0.15 to 0.18 mm, the mass ratio of bentonite to biochar is 1:8 to 20, the pyrolysis temperature is 500 to 800°C, and the pyrolysis time is 30 to 60 minutes.

[0045] The bottom surfaces of the second pool body 31 of the plant restoration zone and the bottom surface 41 of the deep purification module pool are impermeable walls, and the bottom surfaces are flush with the top of the permeable reaction wall watertight wall. The outlet side wall is composed of a steel frame and a permeable geotextile.

[0046] The plant restoration zone 2 is filled with a matrix, which is one of gravel, sand, zeolite, anthracite, bioceramsite, manganese sand, steel slag, waste wood, corn cob particles or a composite filler, and plants are planted on the top of the matrix. The combination ratio of the plant restoration zone matrix needs to be selected according to the polluted water quality, compliance requirements, etc. The most economical ratio.

[0047] The particle size of the inorganic fillers such as gravel, sand, zeolite, etc. is 2-10 mm, and the particle size of the organic fillers such as waste wood blocks, corn cob particles, etc. is 3-6 mm.

[0048] The plant restoration belt 2 has 22 pairs of electric restoration positive and negative electrodes on both sides of the pool. Under the action of the DC electric field, charged heavy metals or polar organic pollutants in the soil move to the electrodes with opposite charges through electrical migration, and are adsorbed by the matrix, absorbed by the plants, and decomposed and removed by microorganisms.

[0049] The cathode electrode and the anode electrode are any one of graphite rod, titanium, stainless steel, conductive metal organic framework material, iron or porous carbon material.

[0050] The low-voltage DC power supply is a solar photovoltaic device. When a DC voltage is applied to the electrodes, a DC electric field will be formed between the electrodes, and the voltage range for driving the electric repair is 0 to 50V.

[0051] The first pool body 21 of the deep purification module is filled with bionic materials as microbial carriers, which are one or both of polypropylene ball fillers or carbon fiber water plants for microbial biofilm formation.

[0052] The bottom 41 of the outlet pool is flush with the bottom of the second pool body 31 of the deep purification module. The pool bottom is made of highly permeable material and serves as a drainage layer to allow the purified water to quickly penetrate into the groundwater environment. The outlet side wall is composed of a steel frame and a permeable geotextile. The pool size is 0.5 to 0.8 m.

[0053] The highly permeable material is a composite layer of pebbles and crushed stones, the particle size of the pebbles is 20 to 50 mm, the particle size of the crushed stones is 10 to 30 mm, and the thickness is 0.5 to 0.6 m;

[0054] The plant restoration belt 2 is added with plant growth-promoting bacteria PGPB to enhance the metal resistance of plants, promote the absorption of heavy metals and nutrients by plants, and thus improve the efficiency of plant restoration. The plants include wetland plants and heavy metal hyperaccumulators. Wetland plants include plants with strong sewage purification capabilities such as reeds, cattails, irises, loosestrife, lily of the valley, canna, etc. Heavy metal hyperaccumulators are extremely resistant to heavy metals such as Cr, Pb, Cu, and Cd, including one or more of dianthus acutus, coreopsis grandiflora, alfalfa, Li's grass, pokeweed, baoshan violet, cosmos, ryegrass, and centipede grass.

[0055] Example:

[0056] Example 1

[0057] from Figures 1-2 It can be seen that the device for the simultaneous removal of multiple target pollutants from groundwater in this embodiment includes a permeable reaction wall 1 and filling materials, a plant restoration belt 2, a deep purification module 3 and an outlet pool 4, and each module is connected in sequence. The permeable reaction wall 1 is arranged along the seepage direction of the groundwater pollution plume. The wall depth is greater than the groundwater pollution plume depth by 1m. The distance between two adjacent walls is 2 to 5m. A permeable grid 11 is arranged in the middle of the wall to divide the reaction area into a first unit 12 and a second unit 13. The grid is welded into a hole-shaped grid by longitudinal and transverse steel bars, and the hole spacing is 2 to 5cm. The wall of the first unit is composed of a steel skeleton and a permeable geotextile, and the outside of the steel skeleton is covered with a permeable geotextile. The steel skeleton is welded vertically and horizontally by a plurality of stainless steel solid pipes. The pipe diameter is 12 to 20mm, the skeleton width is 30 to 50cm, and the permeability coefficient of the permeable geotextile is greater than 5.0*10 -5The second unit wall is composed of a watertight watertight wall 14 and a grille filter 15. The top of the watertight wall is located in the middle of the first unit wall. A grille filter is installed on the top. The size of the grille hole is 1 cm to 2 cm.

[0058] The first unit is filled with adsorption filler, which is one of iron ore, activated zeolite, volcanic rock, ceramsite or composite filter material, with a particle size of 2 to 8 mm. The iron ore is divalent iron ore such as pyrite and siderite. The second unit is filled with active filler, which is biochar composite filler. The filler is spherical porous particles with a particle size of 2 to 4 mm. The material filling needs to make the permeability coefficient of the wall and the reaction zone 2 to 5 times higher than the permeability coefficient of the aquifer. The activated biochar composite filler is filled in a polyethylene mesh bag to prevent water flow impact and loss. The size of the polyethylene mesh bag is 0.5m*0.3m. The active filler can be filled on the ground first and then sealed, and then hoisted and stacked one by one in layers and placed in the second unit of the wall. Specifically, the composition of the biochar composite filler includes 40% to 50% bentonite modified biochar, 20% to 25% zero-valent iron, 10% to 15% clay, 7% to 15% diatomaceous earth, and 3% to 5% ammonium bicarbonate. Clay is used as a bonding raw material, diatomaceous earth is used as a high permeability raw material, and ammonium bicarbonate is used as a pore-forming agent. The bentonite modified biochar is prepared by mixing montmorillonite bentonite and biochar and then pyrolyzing them. The particle size of the montmorillonite bentonite is 0.05-0.1 mm, the particle size of the biochar is 0.15-0.18 mm, the mass ratio of the bentonite to the biochar is 1:8-20, the pyrolysis temperature is 500-800°C, and the pyrolysis time is 30-60 minutes.

[0059] The pollution plume converges into the reaction zone of the permeable reaction wall, where the adsorption filter material and activated biochar composite filler adsorb pollutants such as heavy metals, ammonia nitrogen, inorganic salts, and organic matter. At the same time, zero-valent iron reduction removes some organic pollutants, and the preliminarily treated groundwater enters the plant restoration zone.

[0060] The plant restoration zone 2 consists of a first tank body 21, a matrix, plants, and anode and cathode electrodes 22. The bottom surface 23 of the tank body is an impermeable wall, which is flush with the top of the permeable reaction wall and the water-retaining wall. The outlet wall is composed of a steel skeleton and a permeable geotextile. The tank body is filled with a matrix, which is one of gravel, sand, zeolite, anthracite, bioceramsite, manganese sand, steel slag, waste wood blocks, corn cob particles, or a composite filler, and plants are planted on the top of the matrix. Specifically, the particle size of inorganic fillers such as gravel, sand, zeolite, etc. is 2 to 10 mm, and the particle size of organic fillers such as waste wood blocks and corn cob particles is 3 to 6 mm. The organic filler provides a carbon source for microorganisms. The combination ratio of the matrix needs to be selected according to the polluted water quality and compliance requirements. The most economical ratio.

[0061] Specifically, electric repair cathode and anode electrodes are provided on both sides of the cell body. Under the action of the DC electric field, the charged heavy metals or polar organic pollutants in the soil move to the oppositely charged electrodes by electromigration, and are adsorbed by the matrix, absorbed by the plants, and decomposed and removed by microorganisms. The cathode electrode and the anode electrode are any one of graphite rods, titanium, stainless steel, conductive metal organic framework materials, iron or porous carbon materials. The low-voltage DC power supply is a solar photovoltaic device. When a DC voltage is applied to the electrodes, a DC electric field will be formed between the electrodes, and the voltage range for driving the electric repair is 0 to 60V.

[0062] The residual pollutants enter the plant remediation zone, and the complex pollutants are continuously removed. Some pollutants such as COD and ammonia nitrogen are degraded by microorganisms in the filler matrix, and other pollutants such as heavy metals are absorbed and degraded by plants. After two-stage enhanced treatment, heavy metal pollution is completely removed, and the treated upstream water enters the deep purification module.

[0063] The deep purification module 3 consists of a second tank body 31 and a bionic filler 32. The bottom surface of the tank body is an impermeable wall, which is flush with the top of the permeable reaction wall watertight wall, and the outlet side wall is composed of a steel skeleton and a permeable geotextile. The tank body is filled with bionic materials as a microbial carrier, which is one or both of polypropylene ball fillers or carbon fiber water plants for microbial biofilm. Specifically, the filling density of the polypropylene ball filler is 0.9g / cm3, the diameter is 0.5-1.0cm, and the filling ratio is not less than 75%. The distance between the carbon fiber grasses is 20-30cm, and a weight is hung at the bottom of the water plants to keep the water plants vertically stretched. High-efficiency microbial strains form biofilms on the bionic fillers, and residual organic matter and inorganic pollutants such as ammonia nitrogen are continuously degraded by microorganisms, achieving deep purification of groundwater pollutants.

[0064] The purified water enters the outlet pool 4. The bottom 41 of the outlet pool is flush with the bottom of the deep purification module. The bottom is made of highly permeable material, which serves as a drainage layer to allow the purified water to quickly penetrate into the groundwater environment. The outlet side wall is composed of a steel skeleton and a permeable geotextile. The pool size is 0.5-0.8m. The highly permeable material is a composite layer of pebbles and crushed stones. The pebble particle size is 20-50mm, the crushed stone particle size is 10-30mm, and the thickness is 0.5-0.6m.

[0065] Specifically, the plants to be planted include wetland plants and heavy metal hyperaccumulators. Wetland plants include plants with strong sewage purification capabilities such as reeds, cattails, irises, loosestrife, lily of the valley, canna, etc. Heavy metal hyperaccumulators are extremely resistant to heavy metals such as Cr, Pb, Cu, and Cd, including one or more of the following: Dianthus acutus, Coreopsis grandiflora, alfalfa, Li's grass, Phytolacca baoshanensis, cosmos, ryegrass, and centipede grass.

[0066] Example 2

[0067] from Figures 1-2 It can be seen that the permeable reaction wall 1, the plant restoration belt 2 and the deep purification module 3 are all equipped with an automatic sample detection and analysis device 16 for the automated collection, detection and analysis of multi-layer water quality samples. The automatic sample detection and analysis device mainly samples and analyzes various indicators of the water body through detectors and sensors, including conductivity sensors, dissolved oxygen sensors, heavy metal sensors, COD sensors, NH3-N sensors, microbial (BOD) sensors, organic matter detectors and A / D converters. The groundwater quality detection information is input into the PLC control system through the A / D converter. The maintenance personnel determine the replacement cycle of the permeable reaction wall filler based on the water quality monitoring information. When the filler has been used for a long time and the pollutant removal effect is poor, it can be replaced with a new filler.

[0068] Furthermore, plant growth promoting bacteria (PGPB) can be added to the phytoremediation belt to enhance the metal resistance of plants, promote the absorption of heavy metals and nutrients by plants, and thus improve the efficiency of phytoremediation. Domesticated high-efficiency microbial strains can also be placed in the phytoremediation belt and the deep purification module pool to degrade organic or inorganic matter and deeply purify the water body. The microbial strains include one or more of nitrifying bacteria, denitrifying bacteria, anaerobic dechlorinating bacteria or organic matter degrading bacteria. The addition of bacterial agents is automatically controlled by the PLC system, and the type and time of adding bacterial agents to the phytoremediation belt and deep purification module are determined according to the water quality monitoring information to achieve automated and intelligent operation.

[0069] Example 3

[0070] like Figure 3 As shown, the phytoremediation belt cation and cathode electrode pairs 22 can also be arranged in other ways: (a) anode-cathode, the cation and cathode electrode pairs are set 1m away from the side of the pool body; (b) anode-cathode-anode, two anode electrodes are set on both sides of the pool body, and a cathode electrode is set in the middle; (c) cathode-anode-cathode, two cathode electrodes are set on both sides of the pool body, and an anode electrode is set in the middle or at the bottom. Several electrodes are placed in the phytoremediation belt and arranged in rows. The distance between each electrode pair is less than 30cm, and the electrodes are rod-shaped electrodes. The parameters such as the redox potential, conductivity and temperature of the electrode pair in the effective range are measured, and a larger sustainable DC current is identified and supplied without affecting the normal operation of the electrode system, so as to accelerate the remediation process of complex pollutants.

[0071] In summary, the device for simultaneous removal of multiple target pollutants in groundwater, through the combination of electrodynamics and physical-chemical-phytoremediation technology, performs multi-stage enhanced treatment of pollutants based on the synergistic effect of adsorption-electrochemistry-plant enrichment-microbial degradation, achieves efficient and lasting removal of complex pollutants such as heavy metals, inorganic and organic matter in groundwater, solves the problem of difficulty in coordinated treatment of multiple pollutants, and has the advantages of simple construction, low installation cost, efficient repair, strong applicability, and ecological and environmental protection.

[0072] The present invention realizes the integrated deep treatment of groundwater with complex pollution such as heavy metals, ammonia nitrogen, inorganic salts, and organic matter through the synergistic effect of permeable reaction walls, electrodynamic combined plant remediation, and deep purification modules, and multi-stage enhanced treatment, thereby expanding the application scope of electrodynamic-plant coupled remediation technology.

[0073] The electrodynamic-plant coupling remediation technology can speed up the flow of groundwater and pollutants. Heavy metals, cations and polar organic pollutants in the soil migrate to the cathode under the action of the DC electric field. The pollutants are adsorbed by the matrix, absorbed by the plants, and degraded by microorganisms. At the same time, the addition of plant growth-promoting bacteria and the slow release of carbon sources by the matrix stimulate the growth of microorganisms, which can significantly improve the efficiency of plant remediation and avoid secondary pollution.

[0074] The deep purification module is used to continuously degrade residual pollutants through microorganisms, thereby achieving efficient and lasting removal of groundwater pollutants. The PLC control system determines the type, dosage and time of adding microorganisms based on water quality monitoring information, realizing automated and intelligent operation, effectively improving the stability and utilization rate of high-efficiency degradation bacteria, and solving the problem of low pollutant removal rate.

[0075] The zero-valent iron in the biochar composite filler is used to reduce heavy metals and pollutants. The generated Fe2+ is absorbed by microorganisms and plants as nutrients and enhances their growth and metabolic capabilities, promoting the absorption and degradation of pollutants.

[0076] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0077] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for synchronously removing multiple target pollutants from groundwater, comprising a permeable reaction wall (1), characterized in that: A first unit (12) is arranged on the right side of the permeable reaction wall (1), a water permeable grille (11) is arranged on the right side of the first unit (12), an automatic sample detection and analysis device (16) is arranged above the water permeable grille (11), a second unit (13) is arranged on the right side of the water permeable grille (11), a water-blocking wall (14) and a grille filter (15) are arranged on the right side of the second unit (13), the water-blocking wall (14) is located below the grille filter (15), and a plant restoration belt (2) is arranged on the right side of the grille filter (15). The bottom of the plant remediation belt (2) is provided with a pool bottom surface (23), a positive and negative electrode pair (22) is provided in the plant remediation belt (2), a deep purification module (3) is provided on the right side of the plant remediation belt (2), the deep purification module (3) comprises a first pool body (21), a bionic filler (32) is provided on the right side of the first pool body (21), a water outlet pool (4) is provided on the right side of the bionic filler (32), the water outlet pool (4) comprises a second pool body (31), and a pool bottom (41) is provided at the bottom of the second pool body (31).

2. The device for synchronously removing multiple target pollutants from groundwater according to claim 1, characterized in that: The depth of the permeable reaction wall (1) is greater than the depth of the groundwater pollution plume by 1 m, the distance between two adjacent walls is 2 to 5 m, a permeable grid (11) is arranged in the middle of the wall to divide the reaction area into a first unit (12) and a second unit (13), the grid is welded by longitudinal and transverse steel bars into a hole-shaped grid, and the hole spacing is 2 to 5 cm.

3. The device for synchronously removing multiple target pollutants from groundwater according to claim 1, characterized in that: The wall of the first unit (12) is composed of a steel frame and a permeable geotextile. The steel frame is covered with the permeable geotextile. The steel frame is welded vertically and horizontally by a plurality of stainless steel solid pipes. The pipe diameter is 12 to 20 mm. The frame width is 30 to 50 cm. The permeability coefficient of the permeable geotextile is greater than 5.0*10-5 m / s.

4. The device for synchronously removing multiple target pollutants from groundwater according to claim 1, characterized in that: The wall of the second unit (13) is composed of a watertight water-blocking wall and a grille filter. The top of the water-blocking wall is located in the middle of the wall of the first unit. A grille filter is installed on the top. The size of the grille holes is 1 cm to 2 cm.

5. The device for synchronously removing multiple target pollutants from groundwater according to claim 1, characterized in that: The plant remediation belt (2) is provided with an electric remediation cathode and cathode electrode pair (22) on both sides of the pool, and the cathode and cathode electrode pair (22) includes a cathode electrode and an anode electrode. Under the action of a direct current electric field, charged heavy metals or polar organic pollutants in the soil migrate to electrodes with opposite charges through electrical migration, and are adsorbed by the matrix, absorbed by the plants, and decomposed and removed by microorganisms. The cathode electrode and the anode electrode are any one of graphite rod, titanium, stainless steel, conductive metal organic framework material, iron or porous carbon material; The low-voltage DC power supply is a solar photovoltaic device. When a DC voltage is applied to the electrodes, a DC electric field will be formed between the electrodes, and the voltage range for driving electric repair is 0 to 50V.

6. The device for synchronously removing multiple target pollutants from groundwater according to claim 1, characterized in that: The first pool body (21) of the deep purification module is filled with bionic material as a microbial carrier, which is one or both of polypropylene ball fillers and carbon fiber water plants for microbial biofilm formation.

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