In-situ treatment of acid water seepage from sulfur-containing waste rock piles

Abstract

The present application belongs to the field of wastewater treatment, and particularly relates to an in-situ treatment method for acid water seepage of sulfur-containing waste rock pile, comprising the following steps: drilling and distributing holes on the sulfur-containing waste rock pile to be treated; injecting a sterilizing agent into the holes for sterilization treatment; injecting an alkali solution into the holes after the sterilization treatment for alkali treatment; washing the holes after the alkali treatment to obtain pretreated holes; filling the pretreated holes with bacteria-loaded porous carbon and ferrous salt, and then sealing the holes, so as to perform in-situ treatment on the acid water seepage of the sulfur-containing waste rock pile to be treated; the bacteria-loaded porous carbon is obtained by compounding and modifying raw materials including porous carbon, organic carbon source, activated sludge and sulfate; and the activated sludge is activated sludge containing sulfate-reducing bacteria and iron-reducing bacteria. The present application can adapt to the characteristics of hole treatment, and can realize in-situ long-acting treatment of acid water seepage of sulfur-containing waste rock pile.

Description

Technical Field

[0001] This invention belongs to the field of mine environmental remediation technology, specifically relating to the in-situ treatment of acidic leachate from sulfur-containing waste rock piles in mines. Background Technology

[0002] Over the years, sulfur-containing waste rock piles have gradually produced acidic wastewater due to the oxidation of sulfide minerals. This acidic leachate has a low pH value, sometimes even below 2, and its discharge has a significant impact on the surrounding environment. For some closed and remediated mines, damage to the overburden or impermeable layer allows iron-oxidizing bacteria within the mine pile to oxidize sulfides, producing acidic leachate. Therefore, without disturbing the existing waste rock piles or re-covering them with impermeable layers, the key focus of remediation research is how to control the acidic leachate at its source.

[0003] Acid mine wastewater (AMD) is recognized worldwide as one of the most serious geological and environmental problems caused by mining. Researchers both domestically and internationally have been studying acid mine wastewater for over seventy years, and many countries have recognized the severity of environmental pollution caused by metal mining. Most worryingly, even after mines have been closed for decades, centuries, or even longer, the severe impact of acidic leachate on the ecosystem persists. Current AMD treatment solutions generally fall into two categories: end-of-pipe treatment and source control.

[0004] End-of-pipe treatment refers to the unified treatment of existing acidic mine wastewater. Currently, the main end-of-pipe treatment method is chemical neutralization, which uses lime or limestone to neutralize the pH and precipitate heavy metals as hydroxides. For closed mines, chemical neutralization is costly to operate, and the resulting heavy metal sludge is prone to redissolving, causing secondary pollution. Its disposal becomes a major operational problem and increases costs.

[0005] The main approach to source control is to control the oxidative leaching of sulfides such as pyrite. Based on the steps involved in AMD (Alternating Acid Dissolution), the key factors are pyrite, oxygen, water, and iron-oxidizing bacteria. Controlling individual factors provides a strategy for source control of AMD. Existing technologies include burying alkaline substances in waste rock piles and establishing vegetation cover on the surface of waste rock piles. However, these methods have failed due to the presence of ferric hydroxide, a neutralization product, on the limestone surface, and the inability of vegetation cover to mitigate the acidic nature of the wastewater. Other technologies focus on inhibiting pyrite leaching through physiological, biochemical, chemical, or physical methods. However, research on source control of pyrite dissolution remains at the laboratory evaluation stage, with no reports of industrial applications.

[0006] In recent years, many researchers have utilized the sulfate-reducing and pH-raising effects of sulfate-reducing bacteria (SRB) to treat AMD, developing SRB processes with promising results. Tuttle et al. first proposed using SRB to treat mine wastewater by adding organic waste as nutrients. Liu Xingyu et al. constructed an upflow anaerobic bioreactor (UASB) using SRB and combined it with copper and iron precipitation processes, conducting pilot-scale studies at the Zijinshan Gold and Copper Mine. However, the industrial application of SRB processes for treating AMD is not widespread, especially for some waste rock piles that are generating acidic water, where effective industrial-scale in-situ remediation methods are lacking. Summary of the Invention

[0007] To address the environmental problems caused by acidic water seepage from sulfur-containing waste rock piles, this paper provides an in-situ treatment method for acidic water seepage from sulfur-containing waste rock piles, so as to achieve long-term, effective, and low-cost control of the generation of acidic water seepage from waste rock piles.

[0008] Existing in-situ treatment methods for acidic water seepage from sulfur-containing waste rock piles mainly involve covering the surface with a treatment agent or agitating the soil and modifier. These methods are slow and prone to secondary acid re-seeding. To address this issue, this invention innovatively provides a drilling-based in-situ treatment method. However, early research showed that while this method reduces soil agitation costs and allows for agent injection into the soil, it also presents new problems, such as insufficient contact between the treatment components and the soil, difficulty in controlling treatment conditions due to geothermal activity in the boreholes, reduced treatment efficiency, and difficulty in achieving long-term effectiveness. Furthermore, the difficulty increases further for treatment sites where acidic water seepage has already begun. To address the problems faced by the drilling-based in-situ treatment method of this invention, this invention, after in-depth research, provides the following improvement:

[0009] An in-situ treatment method for acidic water seeping from sulfur-containing waste rock piles involves drilling holes into the sulfur-containing waste rock pile to be treated; injecting a sterilizing agent into the holes for sterilization; injecting an alkaline solution into the holes for alkaline treatment; and washing the holes after alkaline treatment to obtain pretreated holes.

[0010] The pretreatment boreholes were filled with bacteria-laden porous carbon and ferrous salts, and then the boreholes were sealed to treat the seepage acidic water from the sulfur-containing waste rock piles in situ.

[0011] The bacterial-loaded porous carbon is obtained by composite modification of raw materials including porous carbon, organic carbon source, activated sludge and sulfate; the activated sludge is activated sludge containing sulfate-reducing bacteria and iron-reducing bacteria.

[0012] This invention proposes for the first time an in-situ treatment approach for acidic water seeping from borehole-type sulfur-containing waste rock piles. Addressing the challenges of this approach, it innovatively pre-treats the boreholes with sterilization, alkali treatment, and acid washing. This, combined with the synergistic component of bacteria-laden porous carbon, unexpectedly achieves a synergistic effect, adapting to the characteristics of borehole treatment and enabling long-term in-situ treatment of acidic water seeping from sulfur-containing waste rock piles.

[0013] The method of the present invention can be applied to any waste rock pile that needs treatment. For example, due to the urgency of treatment and economic value, it is particularly suitable for waste rock piles that have generated acidic leachate that are difficult to treat technically in the industry.

[0014] In this invention, geological drilling can be used for drilling and hole layout.

[0015] In this invention, the shape of the drill hole is not particularly required and can be controlled according to the characteristics of the drill bit. For example, it can generally be a circular hole.

[0016] In this invention, the drilling parameters can be reasonably controlled according to the pollution situation. For example, the borehole diameter is 30~100mm, the drilling depth accounts for 70%~90% of the total height of the waste rock pile, and the hole spacing is 1~8m.

[0017] In this invention, the sterilizing agent is a non-oxidizing sterilizing agent.

[0018] In this invention, the sterilizing agent is isothiazolinone.

[0019] The sterilizing agent is prepared in advance as a solution with a concentration of 150~350 mg / L.

[0020] In this invention, sterilization is performed 1 to 3 times, with each treatment lasting 3 to 7 days.

[0021] In this invention, the alkaline solution is an aqueous dispersion of at least one alkaline solute selected from sodium hydroxide and calcium hydroxide.

[0022] Preferably, the concentration of the alkaline solute in the alkaline solution is 0.5 wt% to 20 wt%, and more preferably 1 to 12 wt%. When the alkaline solute is sodium hydroxide, its concentration can be reduced to 1 to 4 wt%.

[0023] Preferably, the alkali treatment time is 5 to 30 days.

[0024] In this invention, the washing liquid in the washing stage is water.

[0025] In this invention, the porous carbon is biochar and / or activated carbon. It can be a commercially available product or prepared using conventional carbonization methods.

[0026] In this invention, based on the sterilization, alkali treatment, and washing of the borehole, the combined control of the bacterial-loaded porous carbon and materials enables synergy, adapts to the characteristics of borehole-type in-situ treatment, and thus improves the efficiency and effect of borehole-type in-situ treatment.

[0027] In this invention, the organic carbon source includes at least one biomass and its fermentation products from animal manure, rice straw, stalks and corn cobs.

[0028] Preferably, the organic carbon source is 0.5% to 5% of the weight of the porous carbon, and more preferably 1% to 2.5%.

[0029] In this invention, the activated sludge is taken from the bottom sediment of a sewage treatment plant or a pond or river.

[0030] Preferably, the activated sludge is 1% to 5% of the weight of porous carbon.

[0031] In this invention, sulfate is provided by a sulfate solution with a mass concentration of 0.5% to 5%.

[0032] Preferably, the sulfate is at least one of ferrous sulfate, sodium sulfate, or magnesium sulfate.

[0033] Preferably, the sulfate content is 1% to 10% of the weight of the porous carbon, and more preferably 2% to 5%.

[0034] Preferably, the modification stage is carried out under closed conditions.

[0035] Preferably, the modification time is 20-50 days.

[0036] In this invention, the ferrous salt includes ferrous sulfate.

[0037] Preferably, the ferrous salt is 1% to 5% of the weight of the bacteria-loaded porous carbon, and more preferably 1% to 2%.

[0038] In this invention, after filling, clay can be used to seal the holes.

[0039] Preferably, the sulfur-containing waste rock pile is a waste rock pile that produces acidic leachate, with an sulfur content of 1% to 10%. The initial pH of the acidic leachate from the sulfur-containing waste rock pile is below 4.

[0040] Beneficial effects

[0041] (1) This invention provides an in-situ treatment method for seepage of acidic water from sulfur-containing waste rock piles by drilling.

[0042] (2) The treatment effect is effective and can be maintained in the long term:

[0043] This invention addresses waste rock piles that have already produced acidic leaching water. It utilizes a borehole layout to modify the internal system of the waste rock pile. First, the boreholes undergo sterilization and alkali treatment pretreatment. Then, a combination of the aforementioned quaternary component-loaded porous carbon is employed, further tailored to the microenvironmental characteristics of the borehole treatment method. This transforms the system into a long-term reducing condition, where microorganisms reduce sulfate ions, raising the pH of the water and precipitating harmful metal ions.

[0044] SO4 2- +2C + 2H₂O = 2HCO₃ - +H2S (under the action of anaerobic bacteria)

[0045] (3) Environmentally friendly: This invention utilizes the strong adsorption capacity of porous carbon to adsorb the carbon source material required for the remediation process onto the porous structure of porous carbon. Furthermore, porous carbon itself is a carbon source material that can be used slowly over a long period of time. On the one hand, the organic matter content in the water body will not be released into the water body during the remediation process, resulting in excessive organic matter. On the other hand, it will provide carbon source material for the growth of anaerobic bacteria for a long time, solving the problem that existing technologies cannot provide carbon source material stably for a long time. Moreover, there is no introduction of external materials and microorganisms during the remediation process. The entire remediation process is clean, safe, environmentally friendly, and free from secondary pollution.

[0046] (4) Low cost and wide range of remediation targets: This invention can improve the treatment effect of microbial technology on acidic water seeping from acidified sulfur-containing waste rock piles, effectively overcome the problems of poor microbial adaptability, low remediation effect and biosafety in existing microbial in-situ treatment technologies, and effectively reduce the economic cost of microbial remediation technology. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the process of the present invention;

[0048] Figure 2 The pH values ​​of the effluent from each treatment scheme in Example 1 and Comparative Examples 1-4 are shown. Detailed Implementation

[0049] The present invention will be further described below with reference to the embodiments, but the scope of the present invention is not limited thereto.

[0050] This invention provides a typical in-situ treatment method for acidic water seeping from sulfur-containing waste rock piles, comprising the following steps:

[0051] (1) Drilling holes in waste rock piles: Drill holes in waste rock piles using geological drilling methods;

[0052] (2) Sterilization pretreatment: Inject sterilizing agent into the borehole drilled in step (1);

[0053] (3) Neutralization pretreatment: Inject alkaline solution into the borehole after sterilization in step (2);

[0054] (4) Water washing: Inject clean water into the hole drilled in step (3) to wash the hole;

[0055] (5) Preparation of bacteria-loaded porous carbon: The organic carbon source is brought into full contact with the porous carbon so that it is adsorbed into the pores of the porous carbon (or waste porous carbon that has adsorbed organic matter is directly used), and then mixed with activated sludge and placed in a closed equipment, and sulfate solution is injected to prepare bacteria-loaded porous carbon.

[0056] (6) Injection of bacteria-loaded porous carbon into holes: After mixing ferrous sulfate and bacteria-loaded porous carbon from step (5), the mixture is inserted into the borehole of the waste rock pile and covered with clay to seal the hole;

[0057] (7) Regularly sample and monitor the quality of the leachate.

[0058] The specific steps (1) are as follows: the borehole diameter is 30~100mm, the borehole depth accounts for 70%~90% of the height of the entire waste rock pile, and the spacing between the holes is 1~8m;

[0059] The specific steps (2) are as follows: the sterilizing agent is a commercially available non-oxidizing sterilizing agent, the main component of which isothiazolinone, the number of sterilizations is 1 to 3, and the single action time is 3 to 7 days;

[0060] The specific steps (3) are as follows: inject 0.5%~5% sodium hydroxide alkaline solution or 5%~20% calcium hydroxide slurry into the borehole and treat it with alkali for 5~30 days;

[0061] The specific step (4) is: injecting clean water to wash the hole, the purpose of which is to clean or dilute the residual sterilizing agent and unreacted alkaline solution around the hole. The specific amount of water used for washing depends on the specific conditions of the waste rock pile site.

[0062] The specific steps (5) are as follows: the porous carbon is brought into full contact with an organic carbon source (or waste porous carbon that has been adsorbed with organic matter can be used directly), and then mixed with 1% to 5% activated sludge and placed in a tower-type or trough-type closed container. A 0.5% to 5% mass concentration sulfate solution is injected to prepare the bacteria-loaded porous carbon. The organic carbon source can be one or more fermentation liquids of animal manure, rice straw, straw and corn cob, or directly organic compound products, depending on local conditions. The activated sludge is taken from the bottom mud of sewage treatment plants or ponds and rivers. The bacteria-loaded porous carbon is sealed and cultured at room temperature for 20 to 50 days.

[0063] The specific steps (6) are as follows: ferrous sulfate particles are mixed into the cultured porous carbon in step (5) at a ratio of 1% to 5%, and injected into the borehole of the waste rock pile. Finally, the top is covered with clay to seal the hole.

[0064] The specific steps (7) are as follows: periodically analyze the pH, ORP, TOC and related harmful metal ions of the leachate samples.

[0065] raw material

[0066] The porous carbon described in this invention can be a conventional commercial product in the industry, or it can be prepared using conventional methods. For example, as an optional solution, the porous carbon in the following examples is fruit shell activated carbon with a particle size of 50-200 mesh and a specific surface area >950 m². 2 / g, strength >90%, iodine adsorption value >800mg / g, it comes from Jiangsu Qisheng Carbon Industry.

[0067] Activated sludge can be obtained from domestic wastewater treatment plants or directly from blackened pond and riverbed sediment. Its main active bacteria are sulfate-reducing bacteria and iron-reducing bacteria (bacterial content > 10). 4 (units / g sludge).

[0068] It should be noted that, in order to compare the experimental results, the test area was a region with the same physicochemical properties, and the difference in the initial pH of the water in the borehole was controlled within 0.2.

[0069] Example 1

[0070] A uranium mine in southern my country has generated a large amount of sulfide-containing waste rock (sulfur content of 5.2%) during years of mining operations. These waste rock piles, numbering over ten in size, are located in the valley of the mining area. After remediation years ago, damage to the impermeable layer has led to the production of acidic seepage water with a pH of 2-4. The technology of this invention was used to industrialize the in-situ microbial remediation of the largest waste rock pile, A, including the following steps:

[0071] (1) The nearby drilling team shall be responsible for drilling holes in the waste rock pile with a diameter of 50 mm and a drilling depth of 80% (±5%) of the height of the entire waste rock pile, with a hole spacing of 2.5 m;

[0072] (2) Purchase KS-370 non-oxidizing sterilizing agent (main component isothiazolinone) from Shandong Aike Water Treatment Co., Ltd., prepare it with clean water to a concentration of 200mg / L and inject it into each borehole for sterilization twice, with a single action time of 4 days;

[0073] (3) Inject calcium hydroxide slurry with a mass concentration of about 12% into the borehole and wait for the reaction to neutralize for 20 days;

[0074] (4) Inject a certain amount of clean water into the borehole to wash or dilute the residual sterilizing agent and unreacted alkali solution around the borehole.

[0075] (5) Waste porous carbon (carbon material after adsorbing organic matter (a mixture of styrene and acrylic acid) from a nearby chemical plant’s water treatment workshop was used. The content of adsorbed organic matter accounted for 1.14% of the weight of the porous carbon. After mixing with 1.2% of the weight of the porous carbon and activated sludge from a sewage treatment plant, the porous carbon was placed in a tower-type closed equipment and injected with 1% ferric sulfate solution to prepare bacteria-loaded porous carbon. The amount of solute injected into the ferric sulfate solution was 5% of the weight of the porous carbon. The porous carbon was sealed and cultured at room temperature for 25 days.

[0076] (6) Mix ferrous sulfate particles into the cultured porous carbon in step (5) at a ratio of 1.5%, and inject it into the borehole of the waste rock pile. Finally, cover the top with clay to seal the hole.

[0077] (7) Regularly analyze the pH, ORP, TOC and related harmful metal ions of the leachate samples.

[0078] Comparative Example 1

[0079] Compared with Example 1, the only difference is that in step 5, the porous carbon is replaced with an equal weight of crop straw powder, while the other conditions are the same as in Example 1.

[0080] Comparative Example 2

[0081] Compared with Example 1, the only difference is that steps 2 and 3 are omitted, and step 4 and subsequent processing are performed directly after step 1. The other conditions are the same as in Example 1.

[0082] Comparative Example 3

[0083] Compared with Example 1, the only difference is that in step 5, no organic matter was added (the porous carbon did not pre-adsorb organic matter), and the other conditions are the same as in Example 1.

[0084] Comparative Example 4

[0085] Compared with Example 1, the only difference is that in step 5, ferrous sulfate from step 6 was not added, while the other conditions are the same as in Example 1.

[0086] On-site repair effect monitoring:

[0087] For Example 1 and Comparative Examples 1-4, the remediation effect of the leachate was monitored to ensure the effectiveness of the remediation process and environmental safety. The pH values ​​of the effluent from each remediation scheme are shown in the figure below.

[0088] The specific repair data (sampled on day 400) are shown in the table below (except for pH, all units are mg / L):

[0089]

[0090] As shown in the figure and table above, compared with Comparative Examples 1-4, Example 1 showed that the inhibition system within the waste rock pile was quickly established and remained effective for a long period. From day 20 onwards, the pH value of the leachate remained consistently between 6.5 and 7.5, and U was not detected in the leachate. The concentrations of other metal ions all met the discharge standards. Comparative Example 1, due to the lack of porous carbon, saw its leachate pH value gradually decrease from day 200, and the leachate from day 50 to 150 was black, indicating excessive organic matter content. Comparative Example 2, due to the lack of sterilization and neutralization pretreatment, resulted in severe inhibition of microorganisms in the acidic system, with the leachate pH value remaining below 4.0 throughout the entire remediation period. Comparative Example 3, using porous carbon without a composite organic carbon source, resulted in insufficient release of carbon source substances, leading to a gradual decrease in leachate pH value after day 250. Comparative Example 4 did not utilize the synergistic effect of ferrous iron, and due to the lack of Fe... 2+ It has a stimulating and promoting effect on the growth of reducing bacteria, resulting in a lower overall pH value compared to Example 1, and thus failing to achieve the ideal repair effect.

[0091] The only cost required for the industrial-scale treatment method of this technology is the cost of drilling and preparing bacterial-loaded activated carbon, both of which are one-time investments. The treatment effect is effective for a long time and there is no overall maintenance cost. If the control effect decreases after a certain long period, new bacterial-loaded porous carbon can be implanted again using the existing drill holes.

[0092] Example 2

[0093] This invention was used to industrially treat acidic leachate from a sulfur-containing waste rock pile (sulfur content 7.89%) stored during the mining process of a copper mine in Jiangxi Province. The leachate had a pH value of 1-2, and some heavy metal ions exceeded emission standards. The industrial-scale implementation of this invention's technology for in-situ microbial treatment of the waste rock pile included the following steps:

[0094] (1) A certain exploration team was responsible for drilling holes in the waste rock pile. The hole diameter was 55mm, the drilling depth accounted for about 80% of the height of the entire waste rock pile, and the spacing between the holes was 4~5m.

[0095] (2) Purchase a commercially available non-oxidizing sterilizing agent (main component isothiazolinone) from a certain company, prepare it with water to a concentration of ~300mg / L and inject it into each borehole for sterilization 3 times, with a single action time of 4~5 days;

[0096] (3) Inject a 3.5% sodium hydroxide solution into the borehole and treat with alkali for 6 days;

[0097] (4) Inject a certain amount of clean water into the borehole to wash or dilute the residual sterilizing agent and unreacted alkali solution around the borehole.

[0098] (5) The newly purchased Jiangsu Qisheng Carbon Industry fruit shell porous carbon was fully adsorbed and contacted with industrial grade organic compound lactic acid solution. 1.88% of the weight of the porous carbon lactic acid was adsorbed into the porous medium. Then, 5% of the pond bottom mud was placed in a trough-type sealed container and a 0.85% mass concentration sulfate (sodium sulfate) solution was injected (the amount of solute injected in the sulfate solution was 4.5% of the weight of the porous carbon) for sealed culture of the bacteria-loaded porous carbon at room temperature for 33 days.

[0099] (6) Mix ferrous sulfate powder at a ratio of 1.2% into the porous carbon cultured in step (5) and inject it into the borehole of the waste rock pile. Finally, cover the top with clay to seal the hole.

[0100] (7) Regularly analyze the pH, ORP, TOC and related harmful metal ions of the leachate samples.

[0101] For Example 2, long-term monitoring was used to ensure the effectiveness and environmental safety of the remediation process. Results showed that 23 days after the biofilm-loaded porous carbon was injected into the boreholes, the pH value of the system consistently reached above 6.4, and the concentrations of TOC and major metal ions met emission standards after 350 days of monitoring.

Claims

1. An in-situ treatment method for acidic water seeping from sulfur-containing waste rock piles, characterized in that, Drill holes in the sulfur-containing waste rock pile to be treated; inject a sterilizing agent into the holes for sterilization; after sterilization, inject an alkaline solution into the holes for alkaline treatment; after alkaline treatment, wash the holes to obtain pretreated holes. The pretreatment boreholes were filled with bacteria-laden porous carbon and ferrous salts, and then the boreholes were sealed to treat the seepage acidic water from the sulfur-containing waste rock piles in situ. The bacterial-loaded porous carbon is obtained by composite modification of raw materials including porous carbon, organic carbon source, activated sludge and sulfate; the activated sludge is activated sludge containing sulfate-reducing bacteria and iron-reducing bacteria; The modification stage is carried out under closed conditions; the modification time is 20-50 days. The sterilizing agent is a non-oxidizing sterilizing agent; the sterilization process is repeated 1 to 3 times, with each treatment lasting 3 to 7 days; The porous carbon is biochar and / or activated carbon; The organic carbon source includes at least one biomass and its fermentation products from animal manure, rice straw, stalks, and corn cobs; the organic carbon source is 0.5% to 5% of the weight of porous carbon. Activated sludge is taken from wastewater treatment plants or pond / river bottom sediments; The activated sludge consists of 1% to 5% of the weight of porous carbon. The sulfate is provided by a 0.5% to 5% (w / w) sulfate solution; the sulfate is at least one of ferric sulfate, sodium sulfate, or magnesium sulfate. Sulfates account for 1% to 10% of the weight of porous carbon; Ferrous salts include ferrous sulfate; Ferrous salts account for 1% to 5% of the weight of the bacteria-loaded porous carbon.

2. The in-situ treatment method for acidic water seeping from sulfur-containing waste rock piles as described in claim 1, characterized in that, Drilling and hole layout are carried out using geological drilling methods; The borehole diameter is 30~100mm, the borehole depth accounts for 70%~90% of the total height of the waste rock pile, and the spacing between the holes is 1~8m.

3. The in-situ treatment method for acidic water seeping from sulfur-containing waste rock piles as described in claim 1, characterized in that, The sterilizing agent is isothiazolinone.

4. The in-situ treatment method for acidic water seeping from sulfur-containing waste rock piles as described in claim 1, characterized in that, The alkaline solution is an aqueous dispersion of at least one alkaline solute selected from sodium hydroxide and calcium hydroxide. The concentration of alkaline solute in the alkaline solution is 0.5%~20%; The alkali treatment time is 5 to 30 days.

5. The in-situ treatment method for acidic water seeping from sulfur-containing waste rock piles as described in claim 1, characterized in that, The washing solution used in the washing stage is water.

6. The in-situ treatment method for acidic water seeping from sulfur-containing waste rock piles as described in claim 1, characterized in that, The organic carbon source is 1 to 2.5% of the weight of the porous carbon.

7. The in-situ treatment method for acidic water seeping from sulfur-containing waste rock piles as described in claim 1, characterized in that, Ferrous salts account for 1-2% of the weight of the bacteria-loaded porous carbon.

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