Combined slow-release carbon source of sulfate reducing bacteria and application of combined slow-release carbon source in in-situ prevention and treatment of mine acidic water

Abstract

The invention relates to a combined slow-release carbon source of sulfate reducing bacteria and application of the combined slow-release carbon source in in-situ prevention and treatment of acid mine water, and belongs to the technical field of resources and environment. The invention relates to a combined slow-release carbon source of sulfate reducing bacteria. The combined slow-release carbon source is prepared from a carbonate material, a liquid carbon source material and biodegradable plastic. The combined slow-release carbon source provided by the invention solves the problems of large carbon source loss amount, poor sustainability, difficult supplementation and poor dynamic adjustability when sulfate reducing bacteria are applied to a mine acidic water in-situ control technology, so that sustainable dynamic proliferation of the sulfate reducing bacteria is realized, and the stability of a sulfate reducing bacteria control system is improved; the purposes of mine acid water source reduction and in-situ prevention and control are achieved.

Description

Technical Field

[0001] The invention relates to a combined slow-release carbon source of sulfate-reducing bacteria and application thereof in in-situ prevention and treatment of acidic mine water, belonging to the technical field of resources and environment. Background Art

[0002] Sulfide minerals contained in high-sulfur mining areas form high-sulfur mine water with complex occurrence conditions and prominent environmental problems under the joint action of water, rock and organisms. It is a serious ecological and environmental problem faced by the field of mineral resource utilization in the world. Acidic mine water has the characteristics of low pH value, high iron, high sulfate and heavy metals. If it is not properly handled, it will seriously pollute the surrounding soil and water environment, affect the ecosystem, and endanger the health of animals, plants and humans.

[0003] The use of sulfate-reducing microorganisms to treat mine acidic water has long attracted widespread attention and is currently a method with development potential for treating mine acidic water. Traditional sulfate-reducing bacteria treatment methods are mostly passive treatments for discharged mine acidic water, using sulfate-reducing bacteria to convert SO4 2- Reduction, the reduction products and heavy metal ions in the mine acidic water form sulfide precipitation and are removed simultaneously, reducing SO4 2 In the process of acid mine water, alkalinity is released, thereby neutralizing the pH of mine acid water. Although it has been proven that inoculation of sulfate-reducing bacteria can prevent and control the generation of mine acid water from the source, it has not yet been put into practical application. Compared with passive treatment systems, the important factor that determines the effect of source control is the sustainability of sulfate-reducing bacteria growth and proliferation, and the carbon source is the key to determining the sustainability of sulfate-reducing bacteria growth and proliferation. Organic matter such as sodium lactate, ethanol, acetic acid and their waste carbon sources are fast-acting carbon sources, which are consumed quickly and are soluble liquids. In practical applications, the loss volume is large and the cost is high; agricultural waste carbon sources have low effective ingredients and need to be frequently supplemented in large quantities, which makes it difficult to implement supplementary operations in the completed source control projects. In addition, sulfate-reducing bacteria are extremely sensitive to pH. The low pH of the initial water environment will lead to slow proliferation of sulfate-reducing bacteria and difficulty in forming a dominant population; during the treatment process, the pH value is affected by factors such as rainfall and channel connectivity, and if the carbon source supply of sulfate-reducing bacteria cannot respond quickly to changes in water pH, it will often lead to a decrease in sulfate reduction efficiency until the control system collapses. Due to the lack of carbon source materials that are compatible with the characteristics, conditions and process changes of mine acid water generation, the in-situ prevention and control technology of mine acid water based on sulfate-reducing bacteria is difficult to implement, which greatly limits the practical application of microbial reduction technology in the field of in-situ prevention and control of mine acid water. Summary of the invention

[0004] The purpose of the present invention is to provide a combined slow-release carbon source of sulfate-reducing bacteria and its application in in-situ prevention and treatment of mine acidic water.

[0005] A combined slow-release carbon source for sulfate-reducing bacteria, which is composed of carbonate materials, liquid carbon source materials and biodegradable plastics, wherein:

[0006] The carbonate material is one or more of sodium carbonate, potassium carbonate, calcium carbonate, and magnesium carbonate;

[0007] The liquid carbon source material is a liquid organic substance that can be utilized by sulfate-reducing bacteria;

[0008] The biodegradable plastic is one or more of polyvinyl alcohol, polylactic acid, polycaprolactone, polybutylene succinate, polyhydroxybutyrate / pentanoate, starch, polybutylene adipate-butylene succinate, polybutylene adipate terephthalate, and their copolymers.

[0009] Application of the above-mentioned combined slow-release carbon source as a carbon source for sulfate-reducing bacteria.

[0010] An in-situ prevention and control method for mine acid water, specifically including the following steps:

[0011] Add the above-mentioned combined slow-release carbon source to the source area of mine acid water. After inoculating sulfate-reducing bacteria into the source area of mine acid water, measure the sulfate production in the mine wastewater of the source area of mine acid water.

[0012] Further, it specifically includes the following steps: S1. Determine the addition amount of carbonate materials according to the pH value of the mine acid water in the source area of mine acid water;

[0013] S2. Mix the carbonate materials, liquid carbon source materials and biodegradable plastics in proportion to obtain a combined slow-release carbon source;

[0014] S3. Add the combined slow-release carbon source in S2 to the source area of mine acid water. After inoculating sulfate-reducing bacteria into the source area of mine acid water, measure the sulfate production in the mine wastewater of the source area of mine acid water.

[0015] Further, the specific calculation formula for the addition amount of the carbonate material is:

[0016] M = 10 -X ×(42 - 50) / A;

[0017] Wherein, A is the reaction efficiency, A = 0.1 - 0.5;

[0018] X is the pH value of the mine acid water.

[0019] Further, in S1, if the pH value of the mine acid water is greater than 5, the addition amount of the carbonate material is 0.

[0020] Furthermore, the mass ratio of the liquid carbon source material to the biodegradable plastic is 0.005-1:1.

[0021] Furthermore, in S1, the source of mine acid water can be a pyrite waste rock pile, a coal mine, pyrite, a mined-out area of pyrite waste rock or a waste residue pile.

[0022] The beneficial effects brought by the preparation method provided by the present invention are as follows:

[0023] (1) The combined slow-release carbon source of the present invention solves the problems of large carbon source loss, poor persistence, difficult supplementary addition and poor dynamic regulation faced by the application of sulfate-reducing bacteria in the in-situ prevention and control technology of mine acid water, thereby realizing the sustainable dynamic proliferation of sulfate-reducing bacteria, improving the stability of the sulfate-reducing bacteria prevention and control system, and achieving the purpose of reducing the amount of mine acid water at the source and in-situ prevention and control. The present invention uses carbonate materials as the pH buffer materials for the sulfate-reducing bacteria treatment system, uses liquid carbon source materials as the rapid proliferation carbon source for sulfate-reducing bacteria in the early stage, and uses biodegradable plastics as the sustainable proliferation slow-release carbon source for sulfate-reducing bacteria. Through the combined use of the above materials, the sustainable dynamic proliferation of sulfate-reducing bacteria is realized during the in-situ prevention and control of mine acid water, and the materials can be regularly supplemented by means of reserved feeding holes, monitoring holes or newly added drill holes, etc.

[0024] (2) The in-situ prevention and control method of mine acid water of the present invention uses carbonate materials as the buffer neutralization materials and deoxygenation materials for the sulfate-reducing bacteria treatment system, making the pH value and oxygen conditions of the environment where sulfate-reducing bacteria are inoculated in the initial stage suitable for the growth and proliferation of microorganisms, and playing a buffering role when the pH fluctuates in the later stage; using liquid carbon source materials as the rapid proliferation carbon source for sulfate-reducing bacteria, enabling the inoculated sulfate-reducing bacteria to rapidly proliferate in the mine acid water environment; using biodegradable plastics as the sustainable proliferation carbon source for sulfate-reducing bacteria, realizing the dynamic response of the hydrolysis products of polylactic acid in the water environment with the change of pH value, maintaining the sustainability of the prevention and control of mine acid water, and being applicable to the in-situ prevention and control of mine acid water. Specific Embodiments

[0025] The following further describes the present invention in detail with reference to embodiments, so that those skilled in the art can implement it according to the description in the specification.

[0026] It should be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0027] The first aspect of the present invention protects a combined slow-release carbon source for sulfate-reducing bacteria, which is composed of carbonate materials, liquid carbon source materials and biodegradable plastics.

[0028] Among them, the carbonate material is one or more of sodium carbonate, potassium carbonate, calcium carbonate, and magnesium carbonate. Specifically, it can be a single-substance carbonate, such as sodium carbonate, potassium carbonate, calcium carbonate, and magnesium carbonate, or a mixed salt, such as a mixed salt of sodium carbonate and potassium carbonate, potassium carbonate and calcium carbonate, calcium carbonate and magnesium carbonate, or minerals such as limestone and magnesite containing the above carbonates.

[0029] The liquid carbon source material is a liquid organic matter that can be utilized by sulfate-reducing bacteria, including but not limited to sodium lactate, ethanol, acetic acid, lactic acid, etc.

[0030] The biodegradable plastic is one or more of polyvinyl alcohol (PVA), polylactic acid (PLA), polycaprolactone (PCL), polybutylene succinate (PBS), polyhydroxybutyrate / pentanoate (PHBV), starch (St), polybutylene adipate-butylene succinate (PBSA), polybutylene adipate terephthalate (PBAT), and their copolymers.

[0031] The morphology of the biodegradable plastic can be one or more of granular, powdery, plastic products, and their waste.

[0032] In the present invention, the carbonate material is used as a buffer neutralizing material and deoxygenating material for the sulfate-reducing bacteria treatment system, making the pH value and oxygen conditions of the environment where the sulfate-reducing bacteria are inoculated in the initial stage suitable for the growth and proliferation of microorganisms, and playing a buffering role when the pH fluctuates in the later stage; the liquid carbon source material is used as a carbon source for the rapid proliferation of sulfate-reducing bacteria, enabling the inoculated sulfate-reducing bacteria to rapidly proliferate in the acidic mine water environment; the biodegradable plastic is used as a carbon source for the sustainable proliferation of sulfate-reducing bacteria, realizing the dynamic response of the hydrolysis products of polylactic acid in the water environment with the change of pH value, maintaining the sustainability of the prevention and control of acidic mine water, and being applicable to the in-situ prevention and control of acidic mine water.

[0033] In the present invention, the mass ratio of the liquid carbon source material to the biodegradable plastic is 0.005 - 1:1. Preferably, the mass ratio of the liquid carbon source material to the biodegradable plastic can be 0.005:1, 0.01:1, 0.02:1, 0.04:1, 0.08:1, 0.16:1, 0.32:1, 0.64:1, 1:1, etc.

[0034] In the present invention, the addition amount (kg / m³) of the carbonate material can be determined according to the pH value of the acidic mine water. The specific calculation formula is:

[0035] M = 10 -X ×(42 - 50) / A;

[0036] Among them, A is the reaction efficiency, and A = 0.1 - 0.5;

[0037] X is the pH value of the acidic mine water.

[0038] The present invention secondly aims to protect the use of the above-mentioned combined slow-release carbon source as a carbon source for sulfate-reducing bacteria.

[0039] The third object of the present invention is to protect an in-situ prevention and control method for acid mine water, wherein the above-mentioned combined slow-release carbon source is added to the source of acid mine water, and after inoculating sulfate-reducing bacteria, the sulfate content in the soil of the source of acid mine water or the mine wastewater is tested. Specifically, the source of acid mine water in the present invention can be a pyrite waste rock pile, a coal mine, a pyrite mine, a pyrite waste rock goaf or a waste slag pile.

[0040] In the present invention, if the pH value of the mine acidic water is greater than 5, the added amount of the carbonate material is 0.

[0041] In the present invention, the sulfate-reducing bacteria are indigenous single strains or indigenous microbial enrichments with sulfate-reducing function in the soil of the mine acidic aquatic source, or may be externally introduced single strains or microbial enrichments with sulfate-reducing function.

[0042] It should be noted that the sulfate-reducing bacteria of the present invention are not new strains screened by the inventors. Single strains or microbial enrichments with sulfate-reducing function in the prior art can realize the function of the sulfate-reducing bacteria of the present invention. For example, the bacterium Desulfovibrio YQ-2 screened by the inventors from acidic water sludge of coal mines in Yangquan, Shanxi Province can realize the function of the sulfate-reducing bacteria of the present invention. The strain is deposited in the China Center for Type Culture Collection, and the deposit information is CCTCC AB2022129 (YQ-2). Therefore, the specific information of the sulfate-reducing bacteria in the present invention will not be repeated.

[0043] The following examples all use static leaching experiments to evaluate the in-situ prevention and control effect of mine acidic water, and the prevention and control effect is evaluated by the amount of sulfate generated. The liquid-to-solid ratio of the static leaching experiment is 10:1.

[0044] <Example 1>

[0045] The carbonate material in this embodiment is calcite with a particle size of less than 3 mm, the liquid carbon source material is sodium lactate, the biodegradable plastic is polylactic acid, the mine acidic water comes from the mine acidic water produced by the pyrite waste rock pile in Tongling, Anhui, and the sulfate-reducing bacteria is the bacterium Desulfovibrio YQ-2.

[0046] S1. The pH value of the acidic water in the pyrite waste rock pile mine was tested to be 3.19, and the amount of calcite used was calculated to be 0.20 kg / m3.

[0047] S2. Prepare sodium lactate and polylactic acid at a mass ratio of 0.1:1. Add calcite, sodium lactate and polylactic acid to the waste rock sample, and then inoculate sulfate-reducing bacteria into the waste rock sample. After 30 days, test the sulfate content in the mine wastewater of the waste rock pile.

[0048] After detection, compared with the control group without adding the combined slow-release carbon source, after 30 days, the sulfate production in the water sample decreased by 94.2%, and the production of mine acid water decreased significantly.

[0049] <Example 2>

[0050] In this example, in-situ prevention and control of mine acid water experiments were carried out on mine acid water from the Shandihe Coal Mine in Yangquan, Shanxi. The liquid carbon source material in this example is sodium lactate, the biodegradable plastic is polyvinyl alcohol, and the sulfate-reducing bacteria is Desulfovibrio YQ-2.

[0051] S1. Test the pH value of the mine acid water in this coal mine to be 5.52, the sulfate content to be 1340 mg / L, and the addition amount of carbonate material to be 0.

[0052] S2. Prepare sodium lactate and polyvinyl alcohol at a mass ratio of 0.02:1. Add sodium lactate and polyvinyl alcohol to the waste rock sample, and then inoculate sulfate-reducing bacteria into the waste rock sample. After 30 days, test the sulfate content in the mine wastewater of this coal mine.

[0053] After detection, compared with the control group without adding the combined slow-release carbon source, after 30 days, the sulfate production in the mine wastewater decreased by 97.7%, and the production of mine acid water decreased significantly.

[0054] <Example 3>

[0055] In this example, in-situ prevention and control of mine acid water experiments were carried out on mine acid water from the pyrite mine in Baihe, Shaanxi.

[0056] The carbonate material in this example is sodium carbonate, the liquid carbon source material is ethanol, the biodegradable plastic is polylactic acid, the carbonate material is sodium carbonate, and the sulfate-reducing bacteria is Desulfovibrio YQ-2.

[0057] S1. Test the pH value of the mine acid water in this pyrite mine to be 2.72, the sulfate content to be 5040 mg / L, and calculate the addition amount of sodium carbonate to be 0.17 kg / m³.

[0058] S2. Prepare ethanol and polylactic acid at a mass ratio of 0.01:1. Add sodium carbonate, ethanol and polylactic acid to the soil sample, and then inoculate sulfate-reducing bacteria into the soil sample. After 15 days, test the sulfate content in this soil.

[0059] After detection, compared with the control group without the combined slow-release carbon source, after 15 days, the production of sulfate in the soil sample decreased by 93.2%, and the production of mine acid water decreased significantly.

[0060] In the case of no conflict, the above-mentioned embodiments and features in the embodiments in this article can be combined with each other.

[0061] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A combined slow-release carbon source for sulfate-reducing bacteria, characterized in that: The combined slow-release carbon source is composed of carbonate material, liquid carbon source material and biodegradable plastic, wherein: The carbonate material is one or more of sodium carbonate, potassium carbonate, calcium carbonate and magnesium carbonate; The liquid carbon source material is liquid organic matter that can be utilized by sulfate-reducing bacteria; The biodegradable plastic is one or more of polyvinyl alcohol, polylactic acid, polycaprolactone, polybutylene succinate, polyhydroxybutyrate / valerate, starch, polybutylene succinate-adipate, polybutylene terephthalate-adipate and copolymers thereof.

2. Use of the combined slow-release carbon source as claimed in claim 1 as a carbon source for sulfate-reducing bacteria.

3. A method for in-situ prevention and control of acidic water in mines, characterized in that: The following steps are involved: The combined slow-release carbon source of claim 1 is added to a mine acidic water source, and after sulfate-reducing bacteria are inoculated into the mine acidic water source, the sulfate generation in the mine wastewater of the mine acidic water source is tested.

4. The in-situ prevention and control method for acidic mine water according to claim 3, characterized in that: The specific steps include: S1. Determine the amount of carbonate material to be added according to the pH value of the mine acidic water in the mine acidic water source; S2, mixing the carbonate material, the liquid carbon source material and the biodegradable plastic in proportion to obtain a combined slow-release carbon source; S3. Add the combined slow-release carbon source in S2 to the mine acidic water source, inoculate sulfate-reducing bacteria into the mine acidic water source, and then test the amount of sulfate generated in the mine wastewater of the mine acidic water source.

5. The in-situ prevention and control method for acidic mine water according to claim 4, characterized in that: The specific calculation formula for the amount of carbonate material added is: M=10 -X ×(42~50) / A; Wherein, A is the reaction efficiency, A = 0.1 to 0.5; X is the pH value of mine acidic water.

6. The in-situ prevention and control method of acidic mine water according to claim 4, characterized in that: In S1, if the pH value of the mine acidic water is greater than 5, the amount of carbonate material added is 0.

7. The in-situ prevention and control method for acidic mine water according to claim 4, characterized in that: The mass ratio of the liquid carbon source material to the biodegradable plastic is 0.005 to 1:

1.

8. The in-situ prevention and control method for acidic mine water according to claim 4, characterized in that: In S1, the source of acid mine water can be pyrite waste rock dump, coal mine, pyrite mine, pyrite waste rock goaf or slag dump.