A method for suppressing and controlling mine pile pollution

Abstract

The present invention discloses a method for suppressing and controlling pollution in a mine pile, comprising the following steps: Step 1: constructing a bottom mineral-encapsulated barrier layer, which is established in the interval of 30 to 130 cm below the surface of the slag yard, inducing a mineralized coating on the surface of deep slag particles, and blocking mineral oxidation; Step 2: constructing a middle-layer microbial carrier layer, which is established in the interval of 30 cm below the surface of the slag yard, and creating an optimal space for the growth and reproduction of sulfate-reducing bacteria; Step 3: constructing a surface barrier layer, which is established above the surface of the slag yard, and promoting the formation of a reducing environment in the middle-layer microbial carrier layer. The present invention relates to the technical field of mine pollution control. On the basis of constructing a strong reducing environment from the bottom layer to the surface of the pile, the pollution of the mine pile is treated and controlled in situ, which can completely solve the problems of acidic leaching water seepage and heavy metal pollution in the mine slag yard. The method does not cover the film or soil, and adopts a long-term microbial control method to suppress the pollution of the mine pile, and is green, low-carbon and environmentally friendly.

Description

Technical Field

[0001] The invention relates to the technical field of mine pollution control, and in particular to a method for suppressing and controlling mine pile pollution. Background Art

[0002] my country is rich in metal mineral resources. Nonferrous metal mines provide important basic materials while occupying a large amount of land. As nonferrous metal mining proceeds, heavy metal pollution is inevitably caused to the mining site and the surrounding soil. Heavy metal pollution in the soil caused by nonferrous metal mining has become one of the major environmental pollution problems that has received increasing attention. In response to the heavy metal pollution caused by nonferrous metal mining, people have invented and implemented a variety of control measures, but none of them can completely solve the problem of acidic water pollution and ecological damage in mine slag yards from the root.

[0003] The main mechanism of mine pile pollution is that the dominant microbial population inside the exposed mine pile, the acid-producing aerobic bacteria colonies, continuously oxidize sulfide ions into sulfate ions in an oxidizing environment, while producing hydrogen ions, dissolving the heavy metals in the ore body into ionic state, which migrate with the leaching groundwater, causing dual pollution of acidic wastewater and heavy metal ions.

[0004] For the treatment of mine pile pollution, the commonly used treatment methods in the industry are ex situ landfill disposal or in situ risk control. These methods are all physical membrane isolation methods, which cannot control the heavy metal pollution in the mine pile, nor can they achieve the long-term maintenance of the mine pile reduction environment. In addition, the treatment cost is high, and there are problems such as acid return and secondary pollution. Based on this, finding a low-cost, source-control and long-term maintenance method for suppressing and controlling mine pile pollution has become the research focus of such mine ecological and environmental problems. Summary of the invention

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for suppressing and controlling mine pile pollution, comprising the following steps:

[0006] Step 1: Construct a bottom mineral encapsulation barrier layer, which is built 30-130cm below the surface of the slag yard. Drill injection holes from the surface to the inside of the slag pile, and bury a PVDF catheter with a hole-sealing cover at one end. Then, a mixture of indigenous acidophilic sulfate-reducing bacteria and organic fermentation liquid is injected into the catheter at a regular and quantitative manner to induce mineralization coating on the surface of deep slag particles and prevent mineral oxidation.

[0007] The indigenous acidophilic sulfate-reducing bacteria liquid and the organic matter fermentation liquid are prepared in a ratio of 3:5.

[0008] The injection holes are 9 / 100m 2 The holes are arranged in a field shape, with a hole depth of 100cm.

[0009] The perfusion hole is provided with a PVDF conduit (φ200) with a length of 120 cm. Four holes are staggered in the part of the pipe body buried below 50 cm. The hole diameter is 20 mm, and the distance between two adjacent holes is 15 cm. During perfusion, the perfusion volume of the mixed liquid in each perfusion hole is 50~100L / time, and the injection frequency is generally 1~2 times / month, which can be appropriately increased or decreased depending on the degree of pollution.

[0010] Step 2: Construct a middle microbial carrier layer, which is built 30 cm below the surface of the slag yard. After the surface of the slag yard is simply leveled and cleaned, a mixed material composed of organic fermentation liquid, indigenous acidophilic sulfate-reducing bacteria liquid, and microbial carriers is sprayed on the surface of the slag pile using a wet sprayer to create an optimal growth space for the growth and reproduction of sulfate-reducing bacteria;

[0011] The mixed material is prepared by mixing organic fermentation liquid, indigenous acidophilic sulfate-reducing bacteria liquid and microbial carrier in proportion, and the mixing amount is 4-10 kg / m 2 , indigenous acidophilic sulfate-reducing bacteria liquid 5~10kg / m 2 , microbial carrier and low-oxygen water (dissolved oxygen content DO value <2.0mg / L) are mixed to form a mixed material with a concentration of 20~50%.

[0012] The microbial carrier is composed of lime slurry 2-5 kg / m 2 、Mineralizing microorganisms urease-producing bacteria (Bacillus) liquid 2~5kg / m 2 , calcium-based bentonite 5~10kg / m 2 , Iron modified peat soil 1~3kg / m 2 , Attapulgite powder 0.004~0.01kg / m 2 , carboxymethyl cellulose 0.004~0.01kg / m 2 The mixture is sprayed with a wet spraying machine, and the penetration depth of the material is ensured to be greater than or equal to 30cm, and the spraying surface is uniform and comprehensive.

[0013] Step three: Construct a surface barrier layer above the surface of the slag pile, cover the surface of the slag pile by adding active matrices such as improved matrix and plant-based biomass materials, reduce the redox potential, improve the nutritional structure, and use the downward extension of the roots of trees, shrubs and grasses to consume the oxygen and water entering the mine pile; construct vegetation communities in the form of simulating the combination of natural trees, shrubs and grasses, and quickly form a barrier layer of plant community roots that covers the surface active matrix and extends to different levels below the surface. Vegetation grows to form a dense surface vegetation layer. After plant growth rotation and mowing, microorganisms have a suitable living space and a continuous supply of nutrients; artificial induction maintains a strong reducing environment of the microbial in situ improved layer under the surface vegetation cover.

[0014] In the step three, the surface barrier layer is planted by combining planting and sowing, with young seedlings in nutrient bags (young seedlings in nutrient bags are cultivated through inoculation with directional mycorrhizal fungi and rhizobia) planted and plant seeds sown, to form a quasi-natural vegetation community system with succession of pioneer plants, short-term plants, four-season plants, and long-term resident plants. By selecting "trees, shrubs, and grasses" and simulating the local plant community niche for efficient combination, and utilizing the different growth depths of the roots of trees, shrubs, and grasses, a three-dimensional root network barrier layer is formed in the management area, and local native varieties are preferably selected as plant species.

[0015] In step 3, trees are planted first, and after the trees are planted, shrubs are planted between the trees. The ratio of trees to shrubs is 1:2, and the planting density is 2-3 plants / m 2 , planting varieties are 7~10 / 100m 2 . Herbaceous plants are planted densely by broadcasting mixed grass seeds as ground cover plants. The mixed grass seeds are matched according to the seed germination season.

[0016] In step 3, the tree is a young tree in a nutrient bag, within 2 years of age, with a seedling height of 100-120 cm and a nutrient bag diameter of 18-20 cm; the shrub is a young shrub in a nutrient bag, within 1 year of age, with a seedling height of 60-80 cm and a nutrient bag diameter of 16-18 cm. The seedling root system is required to be intact without wearing bags, grow robustly, and must be a local native plant seedling or cutting seedling that has been domesticated and cultivated through directional mycorrhizal fungi and rhizobia inoculation. It is not necessary to select acid-resistant and heavy metal-accumulating plants according to conventional techniques.

[0017] The specific order of construction steps of the barrier layers represented by the above three steps is: bottom mineral coating barrier layer → middle microbial carrier layer → surface barrier layer.

[0018] Plant metabolites are used to provide a continuous carbon source for the growth of microorganisms such as sulfate-reducing bacteria, and the respiration of plant roots is used to promote the maintenance of the soil reduction environment, drive the virtuous cycle of the ecosystem, and ultimately establish a self-sustaining, non-degrading, maintenance-free positive succession vegetation ecosystem, thereby achieving the purpose of restoring the ecological functions of sulfur-containing slag dumps in mines.

[0019] After the mixture of indigenous acidophilic sulfate-reducing bacteria liquid and organic fermentation liquid in step one enters the sulfur-containing slag pile, on the one hand, it removes pollutants through biochemical reactions with the leached acidic wastewater inside the pile, and on the other hand, through the mineralization action of microorganisms, mineralized crystals are formed inside the pile, filling the gaps between the slag to form an insulating layer, blocking surface water, natural precipitation and oxygen from entering the slag pile and contacting the sulfides on the surface of the slag particles, thereby blocking the oxidation of sulfide substances inside the slag pile to produce acid and the generation of acidic leached wastewater.

[0020] 1) Principles of controlling slag pollutants (where: CH 2 O represents organic matter. )

[0021] SO 4 2- +2CH 2 O + 2H + → H 2 S↑+ 2H 2 CO 3

[0022] SO 4 2- +2CH 2 O → S 2- + 2H 2 CO 3

[0023] 2) Principle of promoting mineralization coating on the surface of slag

[0024] ① The formed metal sulfide adheres to the surface of the slag particles (where Me represents the metal element.)

[0025] xS 2- +2Me x+ →Me 2 S x ↓

[0026] ② The formed metal carbonate precipitates adhere to the surface of the slag particles (where Me represents the metal element.)

[0027] xCO 3 2- +2Me x+ →Me 2 (CO 3 ) x ↓

[0028] ③ Extracellular macromolecular polymers attached to the surface of slag particles

[0029] Extracellular polymers (EPS) are mainly derived from cell lysis and active secretion during cell metabolism. They are polymers composed of macromolecular substances such as proteins, polysaccharides, nucleic acids and humus. Proteins and polysaccharides account for about 70% of the total organic matter, while nucleic acids, lipids, humic acid, uronic acid, etc. account for only 10% of the total organic matter. The loose structural characteristics, biological activity and negative colloid properties of EPS make EPS not only cohesive to slag particles, but also have adsorption and surface complexation effects on heavy metal ions.

[0030] After the urease-producing bacteria in step 2 enter the pile, they adhere to the surface of the slag particles and react with the Ca in the lime slurry. 2+After a series of reactions, calcium carbonate crystals are formed with other microbial carriers. As calcium carbonate crystals continue to accumulate, they eventually fill the gaps between slag particles to form a microbial carrier layer.

[0031] Bacillus and other bacteria can secrete highly active urease, which catalyzes the decomposition of urea inside the bacteria with its efficient urease activity, rapidly increasing the CO2 content in the microenvironment around the bacteria. 3 2- concentration and pH value; secondly, the surface of Bacillus (including cell wall and extracellular polymers) has more negative surface charge than non-mineralized bacteria, and has a stronger adsorption effect on cations, so the positively charged Ca 2+ Can be adsorbed on the surface of Bacillus pasteurianus in large quantities; in high concentrations of CO 3 2- Under alkaline conditions, Ca 2+ The cells will be used as crystal nuclei and settle to form CaCO 3 crystallization.

[0032] Ca 2+ + CO 3 2- → CaCO 3 ↓ (nucleation), Ksp = 3.8 × 10 -9 ;

[0033] The sulfate-reducing bacteria in step 3 can use organic matter and sulfate to undergo biochemical reactions to generate hydrogen sulfide gas, neutralize the acidic environment, and precipitate heavy metals. The relevant mechanisms are as follows:

[0034] 1) Mechanism of sulfate removal by sulfate-reducing bacteria

[0035] SO 4 2- +2CH 2 O + 2H + → H 2 S↑+ 2H 2 CO 3

[0036] SO 4 2- +2CH 2 O → S 2- + 2H 2 CO 3

[0037] 2) Mechanism of metal ion removal by sulfate-reducing bacteria

[0038] xS 2- +2Me x+ → Me 2 S x ↓

[0039] Where: CH 2 O represents organic matter and Me represents metallic elements.

[0040] xCO 3 2- +2Me x+ → Me 2 (CO 3 ) x ↓

[0041] The loose structural characteristics, biological activity and negative colloid charge of extracellular polymers (EPS) enable EPS to adsorb heavy metal ions and have surface complexation effects.

[0042] The anaerobic incubator is composed of a box body with a sealed cover, a flow valve, a controller, an injection pipe, etc. It is automatically controlled after setting a program, and the indigenous acidophilic sulfate-reducing bacteria liquid and nutrient solution are injected at a regular and quantitative time, and the injection depth is in the range of 30 to 130 cm below the surface of the slag yard.

[0043] The original bacteria of indigenous acidophilic sulfate-reducing bacteria are collected from the mine acidic leaching water on site and added to the culture medium for continuous optimization and enrichment. The enriched indigenous acidophilic sulfate-reducing bacteria are inoculated into the culture medium for expansion and cultured anaerobically at 30°C to reduce the redox potential (ORP value) to between -200 and -300, and the culture solution changes from clear to ink color.

[0044] Inoculate the cultured bacterial liquid into the fermentation tank at a 10% inoculation rate, further culture it, and culture it anaerobically at 30°C until the culture liquid changes from clear to ink-colored; repeat this step 3 to 5 times. After the culture is completed, bottle the indigenous acidophilic sulfate-reducing bacteria liquid for storage, and ensure that no air is introduced during the bottling process.

[0045] The culture medium formula is: 2g organic fermentation broth (carbon-nitrogen ratio is 20:1), (NH 4 ) 2 SO 4 0.45 g, KCl 0.05 g, MgSO 4 7H 2 O 0.5g, KH 2 PO 4 0.05 g, Ca(NO 3 ) 2 ·4H 2 O 0.014g, mine acid leaching water 1000mL.

[0046] Preferably, the indigenous acidophilic sulfate-reducing bacteria are obtained by in-situ enrichment in the mine pile, and are cultured nearby using local acid water, without the need for domestication, and are better able to adapt to the local environment.

[0047] Preferably, by adding organic fermentation broth, the redox potential (ORP value) can be quickly reduced to a negative value, and a reducing environment can be quickly established.

[0048] Preferably, the microbial carrier is composed of lime slurry 2-5 kg / m 2 、Mineralizing microorganisms urease-producing bacteria (Bacillus) liquid 2~5kg / m 2 , calcium-based bentonite 5~10kg / m 2 , Iron modified peat soil 1~3kg / m 2 , Attapulgite powder 0.004~0.01kg / m 2 , carboxymethyl cellulose 0.004~0.01kg / m 2 The mixture is sprayed with a wet spraying machine, and the penetration depth of the material is ensured to be greater than or equal to 30cm, and the spraying surface is uniform and comprehensive.

[0049] Preferably, the surface root barrier layer is planted by combining planting and sowing, with young seedlings planted in nutrient bags and plant seeds broadcast, the ratio of trees to shrubs is 1:2, and the planting density is 2-3 plants / m 2 , planting varieties are 7~10 / 100m 2 .

[0050] Preferably, the tree, shrub and grass plant varieties are local native plant seedlings or cuttings that have been domesticated and cultivated through inoculation with directional mycorrhizal fungi and rhizobia. There is no need to select acid-resistant and heavy metal-accumulating plants according to conventional techniques, which overcomes the defect that acid-resistant and heavy metal-accumulating plants cannot form a humus layer and suitable space for microbial growth due to their small biomass. The plant selection is wide, and plants with large biomass suitable for local climatic conditions can be used.

[0051] Preferably, compared with other traditional technologies, the present invention does not use film or soil covering, but uses active matrix covering to construct a reducing environment in situ and supplement nutrients to meet plant growth.

[0052] Preferably, in the present invention, the three-layer three-dimensional structure completely suppresses and controls mine pile pollution from the source by gradually constructing and strengthening the reduction environment. The root layer continuously consumes oxygen and water in the slag body, and continuously extends and grows downward until the plant roots connect the three-layer structure into one, forming an enhanced reduction closed circle.

[0053] It has the following beneficial effects: First, the indigenous acidophilic sulfate-reducing bacteria in the first bottom mineral-encapsulated barrier layer rapidly proliferate using nutrient solution in an oxygen-deficient environment, becoming the dominant bacterial community, inhibiting the survival of acid-producing aerobic bacteria, and weakening the biological oxidation reaction of metal sulfides to produce acidic substances, thereby controlling the acid production at the source; secondly, the middle microbial carrier layer of the second layer can block the leaching water carrying oxygen from entering the area below 30 cm below the surface of the slag yard, isolating oxygen; thirdly, the surface barrier layer further inhibits the growth of acid-producing bacteria, improving The pH value is adjusted and the heavy metal ions are fixed, making the surface environment of the slag suitable for vegetation growth; finally, during the vegetation greening period three months after the treatment, the respiration of the roots of trees, shrubs and grasses can continue to consume the oxygen and water in the slag, creating an oxygen-deficient environment. At the same time, the dead branches and leaves of pioneer plants falling on the surface of the slag will also form a covering layer, which can not only block the scouring effect of rainwater and reduce the infiltration of surface runoff, but also provide a rich carbon source for the probiotics in the third layer of the root barrier layer, promoting their growth, thereby inhibiting acid-producing bacteria. Combining the above four effects, the reducing environment inside the mine pile is established and strengthened for a long time, and can be self-sustaining without excessive maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic diagram of a three-layer strong reduction structure constructed by the method of the present invention;

[0055] Among them, 1. bottom mineral coating barrier layer; 2. middle microbial carrier layer; 3. surface barrier layer; 4. PVDF catheter; 5. catheter hole; 6. flow valve; 7. controller; 8. box for loading mixed liquid; 9. infusion tube; 10. box support frame. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] Example 1

[0058] The implementation site is located in a mine slag dump in Anhui Province. The following methods and steps are used to treat the area:

[0059] Step 1: Construct a bottom mineral-encapsulated barrier layer. Drill an injection hole with a depth of 100 cm on the surface of the slag yard, pre-bury a PVDF catheter in it, and inject the mixed liquid into the pile through the catheter. Utilize biochemical reduction reaction and mineralization reaction to form a barrier layer within 30 cm of the pile surface, inducing the formation of a mineralized coating on the surface of deep slag particles to prevent mineral oxidation. The mixed liquid is prepared by indigenous acidophilic sulfate-reducing bacteria liquid and organic fermentation liquid in a ratio of 3:5. The injection volume of each injection hole is 50L / time, and the injection frequency is once / month;

[0060] Step 2: Construct a middle microbial carrier layer. Use a wet sprayer to spray a mixed material made of organic fermentation liquid, indigenous acidophilic sulfate-reducing bacteria liquid, and microbial carriers on the surface of the slag pile to create an optimal growth environment for the growth and reproduction of sulfate-reducing bacteria, and induce microbial mineralization reactions. A middle microbial carrier layer is formed within 30 cm below the surface of the pile, achieving water and oxygen consumption effects. The dosage of the mixed liquid material is 4 kg / m 2 , indigenous acidophilic sulfate-reducing bacteria liquid 5kg / m 2 , microbial carrier (lime slurry 2kg / m 2 、Mineralizing microorganisms urease-producing bacteria (Bacillus) liquid 2kg / m 2 , calcium-based bentonite 5kg / m 2 , Iron modified peat soil 1kg / m 2 , attapulgite powder 0.004kg / m 2 , carboxymethyl cellulose 0.004kg / m 2 Mixed with low oxygen water (dissolved oxygen content DO value <2.0mg / L) to form a 20% concentration mixed liquid material;

[0061] Step 3: Construct a surface barrier layer. After the surface of the slag yard is simply leveled and cleared, the active improved matrix such as organic compost and plant-based biomass materials is covered to reduce the redox potential in the pile, improve the nutritional structure of the pile, and create an environment for the basic growth of vegetation. The active improved matrix includes the following components per unit area: 8kg / m 2 , fresh organic fertilizer 10kg / m 2 , soil loosening agent 5g / m 2 , indigenous acidophilic sulfate-reducing bacteria liquid 3kg / m 2 , calcium magnesium phosphate fertilizer 0.5kg / m 2 , plant-based biomass materials (crop straw 1kg / m 2 , Grass fiber 0.5kg / m 2 , wood fiber 0.1kg / m 2 ).

[0062] Select local native plants, trees: pine, Ligustrum lucidum, sow nutrient bag seedlings, 2 years old, 100 cm tall, 18 cm diameter, inoculate mycorrhizal fungi and rhizobia; shrubs: Ligustrum lucidum, Robinia pseudoacacia, Rhus chinensis, Amorpha fruticosa, Sapium sebiferum, sow nutrient bag seedlings or cuttings, 1 year old, 60 cm tall, 16 cm diameter, inoculate mycorrhizal fungi and rhizobia. The ratio of trees to shrubs is 1:2, according to the density of 2 plants / m 2 Planting, planting varieties are 7 / 100m 2 The herbs are planted in a broadcast and dense planting manner. Through plant replacement, a natural vegetation community system is formed. Combined with the niche theory, a surface barrier layer is formed to achieve the purpose of long-term effectiveness of the vegetation barrier layer.

[0063] After 12 months of treatment, the treatment effect of the leached water from the slag pile was tested. The pH value of the acidic leached water produced by the pile rose to above 6, close to a neutral environment, and the content of heavy metals such as iron, copper, lead, cadmium, and zinc was greatly reduced, with a reduction of more than 93%. A self-sustaining, non-degraded stable vegetation ecosystem was established on the sulfur-containing slag pile. The test results are shown in Table 1.

[0064] Table 1 Treatment effect of leached water in sulfur-containing slag dump in mine

[0065] index pH iron copper lead cadmium Zinc Before treatment (mg / L) 3.52 295 20.2 0.0235 0.054 0.192 After treatment (mg / L) 6.42 13.45 0.884 0.00162 0.00361 0.0106 Decline rate (%) / 95.4 95.6 94.1 93.3 94.5

[0066] Example 2

[0067] The implementation site is located in a sulfur-containing slag dump of a metal mine in Guangdong Province. The following methods and steps are used to treat the area:

[0068] Step 1: Construct a bottom mineral-encapsulated barrier layer. Drill an injection hole with a depth of 100 cm on the surface of the slag yard, pre-embed a PVDF catheter in it, and inject the mixed liquid into the pile through the catheter. Utilize biochemical reduction reaction and mineralization reaction to form a barrier layer within 30 cm of the pile surface, inducing the formation of a mineralized coating on the surface of deep slag particles to prevent mineral oxidation. The mixed liquid is prepared by indigenous acidophilic sulfate-reducing bacteria liquid and organic fermentation liquid in a ratio of 3:5. The injection volume of each injection hole is 100L / time, and the injection frequency is 2 times / month;

[0069] Step 2: Construct a middle microbial carrier layer. Use a wet sprayer to spray a mixed material made of organic fermentation liquid, indigenous acidophilic sulfate-reducing bacteria liquid, and microbial carriers on the surface of the slag pile to create an optimal growth environment for the growth and reproduction of sulfate-reducing bacteria, and induce microbial mineralization reactions. A middle microbial carrier layer is formed within 30 cm below the surface of the pile, achieving water and oxygen consumption effects. The dosage of the mixed liquid material is 10 kg / m 2 , indigenous acidophilic sulfate-reducing bacteria solution 10kg / m2 , Microbial carrier (lime slurry 5kg / m 2 、Mineralizing microorganisms urease-producing bacteria (Bacillus) liquid 5kg / m 2 , calcium-based bentonite 10kg / m 2 , Iron modified peat soil 3kg / m 2 , Attapulgite powder 0.01kg / m 2 , carboxymethyl cellulose 0.01kg / m 2 Mixed), and low oxygen water (dissolved oxygen content DO value <2.0mg / L) to form a 50% concentration mixed liquid material;

[0070] Step 3: Construct a surface barrier layer. After the surface of the slag yard is simply leveled and cleared, the active improved matrix such as organic compost and plant-based biomass materials is covered to reduce the redox potential in the pile, improve the nutritional structure of the pile, and create an environment for the basic growth of vegetation. The active improved matrix includes the following components per unit area: lime 10kg / m 2 , fresh organic fertilizer 15kg / m 2 , soil loosening agent 8g / m 2 , indigenous acidophilic sulfate-reducing bacteria liquid 5kg / m 2 , calcium magnesium phosphate fertilizer 1.0kg / m 2 , plant-based biomass materials (crop straw 1.5kg / m 2 , Grass fiber 1.0kg / m 2 , wood fiber 0.3kg / m 2 ).

[0071] Select local native plants, trees: camphor, Ligustrum lucidum, Pinus massoniana, sow nutrient bag seedlings, 2 years old, 120 cm tall, 20 cm in diameter, inoculate mycorrhizal fungi and rhizobia; shrubs: Ligustrum lucidum, Robinia pseudoacacia, Rhus chinensis, Amorpha fruticosa, Sapium sebiferum, Lespedeza, Cassia tora, sow nutrient bag seedlings or cuttings, 1 year old, 80 cm tall, 18 cm in diameter, inoculate mycorrhizal fungi and rhizobia. The ratio of trees to shrubs is 1:2, according to the density of 3 plants / m 2 Planting, planting varieties are 10 / 100m 2 The herbs are planted in a broadcast and dense planting manner. Through plant replacement, a natural vegetation community system is formed. Combined with the niche theory, a surface barrier layer is formed to achieve the purpose of long-term effectiveness of the vegetation barrier layer.

[0072] In this embodiment, due to the high degree of pollution of sulfur-containing slag, the amount and frequency of microbial liquid injection were increased. After 12 months of treatment, the treatment effect of the leached water of the slag pile was tested. The pH value of the pile environment rose to above 6, close to a neutral environment, and the content of heavy metals such as arsenic, copper, lead, cadmium, and zinc was greatly reduced, with a reduction of more than 98%. A self-sustaining, non-degraded stable vegetation ecosystem has been initially established on the sulfur-containing slag pile. The test results are shown in Table 2.

[0073] Table 2 Effect of leaching water treatment in mine slag dump

[0074] index pH arsenic copper lead cadmium Zinc Before treatment (mg / L) 2.78 11.2 35.8 0.077 3.09 1069 After treatment (mg / L) 6.65 0.0482 0.175 0.00133 0.00467 0.65 Decline rate (%) / 99.6 99.5 98.3 99.8 99.9

[0075] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications are considered to be within the scope of protection of the present invention.

Claims

1. A method for suppressing and controlling mine pile pollution, characterized in that: The following steps are involved: Step 1: Construct a bottom mineral encapsulation barrier layer, which is built in the interval of 30~130cm below the surface of the slag yard. Drill injection holes from the surface to the inside of the slag pile, and pre-embed a PVDF catheter with a hole-sealing cover at one end. Then, a mixture of indigenous acidophilic sulfate-reducing bacteria liquid and organic matter fermentation liquid is injected into the catheter at a regular and quantitative manner to induce the formation of a mineralized coating on the surface of deep slag particles to prevent mineral oxidation; Step 2: Construct a middle microbial carrier layer, which is built 30 cm below the surface of the slag yard. After the surface of the slag yard is simply leveled and cleaned, a mixed material composed of organic fermentation liquid, indigenous acidophilic sulfate-reducing bacteria liquid, and microbial carrier is sprayed on the surface of the slag pile using a wet sprayer to create an optimal growth space for the growth and reproduction of sulfate-reducing bacteria. Step 3: Construct a surface barrier layer above the surface of the slag pile, cover the surface of the slag pile by adding improved substrates and plant-based biomass materials, and construct a vegetation community in the form of a natural combination of trees, shrubs and grasses to promote the formation of a reducing environment in the middle microbial carrier layer; The specific order of construction steps of each barrier layer represented by the above three steps is: bottom mineral coating barrier layer → middle microbial carrier layer → surface barrier layer; The microbial carrier is composed of lime slurry 2-5 kg / m 2 、Mineralizing microorganisms urease-producing bacterial liquid 2~5kg / m 2 , calcium-based bentonite 5~10kg / m 2 , Iron modified peat soil 1~3kg / m 2 , Attapulgite powder 0.004~0.01kg / m 2 , carboxymethyl cellulose 0.004~0.01kg / m 2 Mixed.

2. A method for suppressing and controlling mine pile pollution according to claim 1, characterized in that: During the perfusion in step 1, the perfusion volume of the mixed solution consisting of the indigenous acidophilic sulfate-reducing bacteria solution and the organic matter fermentation solution in each perfusion hole is 50-100 L / time, and the injection frequency is 1-2 times / month, which can be appropriately increased or decreased depending on the degree of pollution.

3. The method for suppressing and treating mine pile pollution according to claim 1, characterized in that: The indigenous acidophilic sulfate-reducing bacteria liquid described in step 1 is prepared by in-situ enrichment of acid wastewater from mine sludge and direct expansion of the acid wastewater.

4. The method for suppressing and controlling mine pile pollution according to claim 1, characterized in that: The amount of organic fermentation liquid prepared in step 2 is 4-10 kg / m 2 , the dosage of indigenous acidophilic sulfate-reducing bacteria solution is 5~10kg / m 2 , add hypoxic water to the mixed solution to adjust the concentration to 20~50%.

5. The method for suppressing and treating mine pile pollution according to claim 1, characterized in that: The improved substrate in step 3 is composed of 8-10 kg / m 2 , fresh organic fertilizer 10~15kg / m 2 , soil loosening agent 5~8g / m 2 , indigenous acidophilic sulfate-reducing bacteria solution 3~5kg / m 2 , calcium magnesium phosphate fertilizer 0.5~1.0kg / m 2 The plant-based biomass material is composed of 1-1.5 kg / m 2 , Grass fiber 0.5~1.0kg / m 2 , wood fiber 0.1~0.3kg / m 2 Material composition.

6. The method for suppressing and treating mine pile pollution according to claim 1, characterized in that: The vegetation community of trees, shrubs and grasses described in step 3 is planted by combining planting and sowing, with young seedlings planted in nutrient bags and plant seeds broadcast. The ratio of trees to shrubs is 1:2, and the planting density is 2-3 plants / m 2 , planting varieties are 7~10 / 100m 2 .

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