Sulfate reducing bacteria mixed bacteria solution for mine acid wastewater treatment as well as preparation method and application of sulfate reducing bacteria mixed bacteria solution

Abstract

The invention relates to the technical field of environmental microorganisms, and particularly discloses a sulfate reducing bacteria mixed bacteria solution for mine acid wastewater treatment as well as a preparation method and application of the sulfate reducing bacteria mixed bacteria solution. The sulfate reducing bacteria mixed bacteria solution disclosed by the invention is prepared from the following strains with relative abundance: 28.0 to 35.0 percent of bacteroides, 13.0 to 16.0 percent of toathouse bacillus, 8.0 to 12.0 percent of desulfation coccus, 2.5 to 3.6 percent of desulfation leaf bacteria, 2.0 to 2.7 percent of desulfation vibrio and 0.9 to 1.7 percent of sulfuration spirillum. The method comprises the following steps: taking a mine acid wastewater sediment sample as a raw material to prepare a sulfate reducing bacteria mixed bacteria solution; the bacterial liquid can reduce sulfate in the mine acid wastewater into sulfide, generate alkalinity, increase the pH value of the mine acid wastewater, and remove heavy metals in the mine acid wastewater in a precipitation form, so that the mine acid wastewater is harmless, and effective treatment of the mine acid wastewater is realized.

Description

Technical Field

[0001] This application relates to the technical field of environmental microbiology, specifically to a mixed bacterial solution of sulfate-reducing bacteria for the treatment of acidic wastewater from mines, its preparation method, and its application. Background Technology

[0002] Acidic mine wastewater is a common pollutant generated during mining operations. Its main components include high concentrations of sulfates, heavy metal ions (such as iron and manganese), and acidic substances with low pH values. The environmental harm caused by acidic mine wastewater is multifaceted. Its acidic components corrode soil and water bodies, leading to ecosystem imbalance and affecting plant growth and aquatic life. Simultaneously, the heavy metal ions it contains are biotoxic and can accumulate through the food chain, ultimately posing a potential threat to human health. Furthermore, the discharge of acidic mine wastewater also pollutes surface water and groundwater, impacting the sustainable use of water resources. Therefore, how to effectively treat acidic mine wastewater has become an urgent environmental problem to be solved in mining operations.

[0003] Currently, the main methods for treating acidic mine wastewater include physicochemical and biological methods. Physicochemical methods, such as neutralization and precipitation, can rapidly reduce the acidity and heavy metal concentration of wastewater, but they also suffer from high treatment costs and secondary pollution problems such as the generation of large amounts of chemical sludge. Biological methods utilize the metabolic activity of microorganisms to treat wastewater, offering advantages such as low cost and environmental friendliness. Among these, sulfate-reducing bacteria (SUBRR) are considered a promising biological treatment technology because they can reduce sulfate to sulfides while simultaneously precipitating heavy metal ions.

[0004] However, most studies currently use pure strains of sulfate-reducing bacteria, which typically have poor treatment capabilities for actual wastewater. Considering the complexity of actual sulfate wastewater treatment, enriching and culturing indigenous sulfate-reducing bacteria communities can help them cope with real acidic mine wastewater, thereby stabilizing and improving treatment capacity and efficiency.

[0005] Therefore, there is an urgent need to develop a green and efficient method for treating acidic wastewater from mines, which is of great significance for protecting the ecological environment of mines and human health. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides a mixed bacterial solution of sulfate-reducing bacteria for the treatment of acidic wastewater from mines, its preparation method, and its application.

[0007] This application provides a mixed bacterial solution of sulfate-reducing bacteria for the treatment of acidic wastewater from mines, specifically including the following strains in relative abundance: Bacteroides 28.0-35.0%, Bacillus septicemia 13.0-16.0%, Desulfococcus 8.0-12.0%, Desulfospirillum 2.5-3.6%, DesulfoVibrio 2.0-2.7%, and Spirochete sulfide 0.9-1.7%.

[0008] The sulfate-reducing bacteria mixed bacterial solution provided in this application was obtained by enrichment and cultivation from the bottom sediment of acidic mine wastewater. The pH is weakly acidic and the temperature is room temperature. The bacterial solution has good pH adaptability, sulfate reduction ability and heavy metal removal ability.

[0009] The sulfate-reducing bacteria mixed solution provided in this application is composed of multiple bacterial genera with specific relative abundance ratios, which can work synergistically to rapidly reduce sulfate to sulfides and generate alkalinity, thereby increasing the pH of acidic mine wastewater. At the same time, it removes heavy metals in acidic mine wastewater by precipitation, thus rendering the acidic mine wastewater harmless and realizing the treatment of acidic mine wastewater, which is of great significance for the bioremediation of acidic mine wastewater.

[0010] This mixed bacterial solution does not generate secondary pollution during wastewater treatment, avoids the production of chemical sludge, and conforms to the green and low-carbon concept. It can adapt to environments with different concentrations of sulfate and heavy metal ions, and has broad applicability to the treatment of acidic mine wastewater, capable of treating various complex wastewater compositions. By enriching and cultivating indigenous sulfate-reducing bacteria, the mixed bacterial solution exhibits stable treatment effects in practical applications, unaffected by seasonal or environmental changes. This sulfate-reducing bacteria mixed bacterial solution provides a highly efficient, economical, and environmentally friendly new method for the bioremediation of acidic mine wastewater, demonstrating significant innovation and practicality.

[0011] Preferably, the sulfate-reducing bacteria mixed bacterial solution specifically includes the following strains in relative abundance: Bacteroides 30.0-33.0%, Bacillus septicemia 14.0-15.0%, Desulfococcus 9.0-11.0%, Desulfospirillum 2.7-3.4%, DesulfoVibrio 2.1-2.5%, and Sulfide Spirochete 1.1-1.5%.

[0012] Preferably, the sulfate-reducing bacteria mixed bacterial solution specifically includes the following strains in relative abundance: Bacteroides 31.0-33.0%, Bacillus septicemia 14.0-15.0%, Desulfococcus 9.0-10.0%, Desulfophyllum 2.7-3.4%, DesulfoVibrio 2.1-2.5%, Sulfide Spirochete 1.1-1.5%, Acidic Cocci 5.1-8.5%, Riken 2.9-3.8%, Raoultella 2.4-3.5%, Enterobacter 2.1-4.2%, Amniporium 1.2-2.5%, and Anaerobic Filamentosum 1.1-2.2%.

[0013] Preferably, the sulfate-reducing bacteria mixed bacterial solution specifically includes the following strains in relative abundance: Bacteroides 30.0-33.0%, Bacillus septicemia 14.0-15.0%, Desulfococcus 9.0-10.0%, Desulfophyllum 2.7-3.4%, DesulfoVibrio 2.1-2.5%, Spirochetes sulfide 1.1-1.5%, Acidococcus 6.1-7.0%, Riken 3.0-3.5%, Raoultella 2.8-3.2%, Enterobacter 2.1-2.8%, Amniporium 1.6-2.0%, Anaerobic filaments 1.5-2.0%, Stylobacterium 1.4-1.8%, Acinetobacter 1.1-1.5%, Clostridium rumenans 0.8-1.2%, and Trichophyton 0.4-0.6%; the remainder being other strains; among the other strains, the content of each strain is <0.5%.

[0014] Secondly, this application provides a method for preparing the above-mentioned sulfate-reducing bacteria mixed bacterial solution, specifically including the following steps in sequence: Collect sediment samples from acidic mine wastewater; place the sediment samples in an enrichment culture medium at a ratio of 18-22g: 800-1200mL, and enrich them for 37-43 days under dark and normal temperature conditions to obtain an enriched bacterial solution, which is a mixed bacterial solution of sulfate-reducing bacteria. The enrichment medium comprises the following components at the following concentrations: KH₂PO₄ 0.6-0.8 g / L, NH₄Cl 1.3-1.5 g / L, CaCl₂·6H₂O 0.15-0.20 g / L, MgSO₄·7H₂O 2.4-2.8 g / L, Na₂SO₄ 0.8-1.2 g / L, yeast extract 0.4-0.6 g / L, sodium lactate 2.5-3.0 g / L, and malt extract 0.05-0.15 g / L. The pH of the enrichment medium is 6.0-7.5.

[0015] The method for preparing sulfate-reducing bacteria mixed bacterial solution provided in this application is entirely based on biological processes. It is low-cost, environmentally friendly, and green and sustainable. It can treat acidic mine wastewater on a large scale, and is of great significance for the passive restoration of historically abandoned mines.

[0016] Preferably, the enrichment medium comprises the following components at the following concentrations: KH₂PO₄ 0.65-0.78 g / L, NH₄Cl 1.3-1.5 g / L, CaCl₂·6H₂O 0.15-0.20 g / L, MgSO₄·7H₂O 2.5-2.7 g / L, Na₂SO₄ 0.8-1.2 g / L, yeast extract 0.4-0.6 g / L, sodium lactate 2.6-2.9 g / L, and malt extract 0.07-0.12 g / L, and the pH of the enrichment medium is 6.8-7.2.

[0017] Preferably, the method for preparing the sulfate-reducing bacteria mixed bacterial solution further includes subculturing the enriched bacterial solution; the subculturing method is as follows: the enriched bacterial solution is transferred to an improved culture medium at a ratio of 8-12 mL: 80-120 mL, and subcultured once every 12-15 days under dark and room temperature conditions; the improved culture medium includes the following components at the following concentrations: Na2SO4 0.8-1.2 g / L, yeast extract 0.4-0.6 g / L, sodium lactate 0.5-0.9 g / L, malt extract 0.05-0.15 g / L, and the pH of the improved culture medium is 6.8-7.2.

[0018] Preferably, the improved culture medium comprises the following components at the following concentrations: Na2SO4 0.8-1.2 g / L, yeast extract 0.4-0.6 g / L, sodium lactate 0.6-0.8 g / L, and malt extract 0.07-0.12 g / L, and the pH of the improved culture medium is 6.8-7.2.

[0019] Thirdly, this application provides an application of the above-mentioned sulfate-reducing bacteria mixed bacterial solution or the sulfate-reducing bacteria mixed bacterial solution prepared by the above preparation method in the treatment of acidic wastewater from mines.

[0020] Fourthly, this application provides a method for treating acidic mine wastewater, which uses the above-mentioned sulfate-reducing bacteria mixed bacterial solution or the sulfate-reducing bacteria mixed bacterial solution prepared by the above-mentioned preparation method to treat the acidic mine wastewater.

[0021] In the actual application of acidic wastewater treatment in mines, it is necessary to screen for inexpensive and efficient natural carbon source wood chips and use them for the growth and reproduction of sulfate-reducing bacteria.

[0022] In summary, the technical solution of this application has the following effects: This application uses samples of acidic mine wastewater sediment as raw material and optimizes the screening, cultivation, and reaction conditions of sulfate-reducing bacteria to prepare a mixed bacterial solution containing multiple sulfate-reducing bacteria. This bacterial solution exhibits good pH adaptability, sulfate reduction capacity, and heavy metal removal capacity. Furthermore, the method for preparing sulfate-reducing bacteria provided in this application is based on a biological process, is low-cost, environmentally friendly, and greenly sustainable, and can treat acidic mine wastewater on a large scale, which is particularly significant for the passive remediation of historically abandoned mines.

[0023] This application provides a method for biological treatment of acidic mine wastewater using sulfate-reducing bacteria, which improves the feasibility and reliability of the technology; ensures the high efficiency of the mixed bacterial solution of sulfate-reducing bacteria in actual site applications, so that both sulfate reduction rate and heavy metal removal rate can reach a high level; this method utilizes biological treatment technology to reduce the treatment cost of acidic mine wastewater, avoids secondary pollution caused by traditional physicochemical methods, and has significant environmental and economic benefits. Attached Figure Description

[0024] Figure 1 These are photographs taken on day 0 and day 14 during the preparation of the sulfate-reducing bacteria mixed bacterial solution in Example 1.

[0025] Figure 2 This refers to the microbial community structure of the sulfate-reducing bacteria mixed bacterial solution in Example 1.

[0026] Figure 3 The diagram shows the physical changes of the sulfate-reducing bacteria mixed solution in Example 1 during the simulated wastewater treatment process.

[0027] Figure 4 The diagram shows the pH changes during the simulated wastewater treatment process using the sulfate-reducing bacteria mixed bacterial solution from Example 1.

[0028] Figure 5 The graph shows the changes in ORP during the simulated wastewater treatment process using the sulfate-reducing bacteria mixed bacterial solution from Example 1.

[0029] Figure 6 To apply the sulfate-reducing bacteria mixed bacterial solution from Example 1 to the simulated wastewater treatment process of Fe 2+ Concentration change graph.

[0030] Figure 7 The graph shows the change in sulfide concentration during the simulated wastewater treatment process using the sulfate-reducing bacteria mixed bacterial solution from Example 1.

[0031] Figure 8 The graph shows the change in sulfate concentration during the simulated wastewater treatment process using the sulfate-reducing bacteria mixed bacterial solution from Example 1.

[0032] Figure 9 This is a graph showing the pH changes during the actual wastewater treatment process using the sulfate-reducing bacteria mixed bacterial solution from Example 2.

[0033] Figure 10 To apply the sulfate-reducing bacteria mixed bacterial solution from Example 2 to the actual wastewater treatment process, Fe... 2+ Concentration change graph.

[0034] Figure 11 The graph shows the change in sulfate concentration during the actual wastewater treatment process using the sulfate-reducing bacteria mixed bacterial solution from Example 2. Detailed Implementation

[0035] The present application will be further described in detail below with reference to embodiments, comparative examples and performance test results. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0036] Example

[0037] Example 1

[0038] Example 1 provides a mixed bacterial solution of sulfate-reducing bacteria and its preparation method.

[0039] A sample of sediment from the bottom of an acidic wastewater mine in Anhui Province was collected, sealed, and transported to the laboratory. The sampling location was a typical area where acidic wastewater from a mine accumulates. The sediment was yellow in color, indicating that it was contaminated with heavy metals such as iron.

[0040] An enrichment medium was prepared, consisting of the following components at the following concentrations: KH₂PO₄ 0.7 g / L, NH₄Cl 1.4 g / L, CaCl₂·6H₂O 0.17 g / L, MgSO₄·7H₂O 2.6 g / L, Na₂SO₄ 1.0 g / L, yeast extract 0.5 g / L, sodium lactate 2.7 g / L, and malt extract 0.1 g / L. The pH of the medium was adjusted to 7.0 using 0.2 mol / L NaOH and 0.2 mol / L HCl solutions. The medium was then sterilized at 0.1 MPa and 121°C for 20 min. The malt extract (model Y017FC) was purchased from Hangzhou Best Biotechnology Co., Ltd. When using it, 130.1 g of the extract was added to 1000 mL of distilled water, stirred, heated to boiling until completely dissolved, and then autoclaved at 121°C for 15 min.

[0041] Take 20g of sediment sample and place it in a 1L blue-capped bottle containing enrichment medium. Incubate in the dark at room temperature (24℃) for 40 days to obtain the enriched bacterial solution, which is the sulfate-reducing bacteria mixed solution.

[0042] like Figure 1 The images shown are actual photos taken on day 0 and day 14 during the preparation of the sulfate-reducing bacteria mixed bacterial solution. On day 0, the solution was clear and transparent when it was first enriched, and contained yellow sediment. After day 14 of enrichment culture, the solution turned black. The black color is considered to be metal sulfide, indicating that the mixed bacterial solution containing sulfate-reducing bacteria was successfully enriched.

[0043] After 16S gene sequencing, the microbial community structure of the sulfate-reducing bacteria mixed culture prepared in Example 1 (shown as relative abundance at the genus level) is as follows: Figure 2As shown, the strains with the following relative abundances mainly include: Bacteroides 33.3%, Bacillus septicemia 14.6%, Desulfococcus 9.6%, Desulfophyllum 3.1%, DesulfoVibrio 2.3%, and Sulfide Spirochetes 1.3%; as detailed in Table 2.

[0044] The bacterial culture was then passaged using a modified culture medium at a passage ratio of 10%. Specifically, 10% (v / v) of the bacterial culture was added to 90% (v / v) of fresh modified culture medium. Passage was conducted in the dark at room temperature, every two weeks. The modified culture medium consisted of: 1.0 g / L Na₂SO₄, 0.5 g / L yeast extract, 0.7 g / L sodium lactate, and 0.1 g / L malt extract, with a pH of 7.0.

[0045] Examples 2-4 Examples 2-4 provide a mixed bacterial solution of sulfate-reducing bacteria and its preparation method.

[0046] The difference between the above embodiments and Embodiment 1 is that the pH or composition of the enrichment culture medium is different, as shown in Table 1.

[0047] Table 1. Concentrations of each raw material in the enrichment culture medium in Examples 1-4 and Comparative Examples 1-3.

[0048] All other process parameters in the above embodiments are the same as those in Embodiment 1.

[0049] Comparative Example Comparative Examples 1-3 Comparative Examples 1-3 each provide a mixed bacterial solution of sulfate-reducing bacteria and its preparation method.

[0050] The difference between the above comparative examples and Example 1 is that the pH or composition of the enrichment culture medium is different, as shown in Table 1.

[0051] All other process parameters in the above comparative examples were the same as in Example 1. The specific results of the microbial community structure composition of the sulfate-reducing bacteria mixed bacterial solutions prepared in Comparative Examples 1-3 after 16S gene sequencing are shown in Table 2.

[0052] Performance testing (1) Microbial community structure of sulfate-reducing bacteria mixed bacterial solution The enriched bacterial suspension samples (i.e. sulfate-reducing bacteria mixed suspensions) prepared in Examples 1-4 and Comparative Examples 1-3 were subjected to 16S gene sequencing to detect the microbial community structure composition (shown as relative abundance at the genus level). The specific results are shown in Table 2.

[0053] Table 2. Detection results of microbial community structure composition in Examples 1-4 and Comparative Examples 1-3

[0054] As shown in Table 2, the test results indicate that by using the technical solutions of Examples 1-4 of this application, an enrichment culture medium with a pH of 6.0-7.5 was prepared using specific types and concentrations of raw materials. The raw materials of the mine acidic wastewater sediment sample were enriched and cultured. The resulting mixed bacterial solution of sulfate-reducing bacteria contained a variety of sulfate-reducing bacteria, including 8.0-12.0% of desulfococci, 2.5-3.6% of desulfophylls, 2.0-2.7% of desulfovibrio, and 0.9-1.7% of spirochetes.

[0055] Application Example 1 Application Example 1 provides a method for treating simulated acidic mine wastewater using a mixed solution of sulfate-reducing bacteria.

[0056] In Application Example 1, the sulfate-reducing bacteria mixed bacterial solution prepared in Example 1 was used as the research object.

[0057] This stage is the laboratory batch experiment stage, aiming to study the treatment effect of the sulfate-reducing bacteria mixed bacterial solution on simulated laboratory wastewater. Based on the measured indicators and actual needs of acidic wastewater from a certain mine, simulated wastewater was used, with the following composition: MgSO4·7H2O 4.0 g / L; Na2SO4 3.5 g / L; sodium lactate 2.0 g / L; FeSO4·7H2O 3 g / L; wastewater pH 4.7. 100 mL of the sulfate-reducing bacteria mixed bacterial solution prepared in Example 1 was added to 1150 mL of simulated wastewater to test the treatment effect of the sulfate-reducing bacteria mixed bacterial solution on the simulated wastewater.

[0058] Figure 3 The figure shows the physical changes of the sulfate-reducing bacteria mixed bacterial solution during the simulated wastewater treatment process. As can be seen from the figure, during the simulated treatment process, the wastewater color gradually changed from transparent to black. After that, the black precipitate fell off and the wastewater turned transparent again.

[0059] Figure 4 The graph shows the pH change of the sulfate-reducing bacteria mixed solution during the treatment of simulated wastewater. As can be seen from the graph, the sulfate-reducing bacteria mixed solution can gradually increase the pH of the simulated wastewater from 4.7 to about 5.6 within 53 days (it can work under acidic pH).

[0060] Figure 5 The graph shows the ORP changes of the sulfate-reducing bacteria mixed bacterial solution during the simulated wastewater treatment process. As can be seen from the graph, the ORP of the sulfate-reducing bacteria mixed bacterial solution remained between -300 and -250 mV in the later stage of the simulated treatment process.

[0061] Figure 6 The effect of a mixed bacterial solution of sulfate-reducing bacteria on Fe in a simulated wastewater treatment process. 2+ Concentration change graph; As shown in the graph, the mixed bacterial solution of sulfate-reducing bacteria can reduce the Fe concentration in simulated wastewater by 53 days. 2+ The concentration decreased from 592.0 mg / L to 64.6 mg / L, and the heavy metal Fe... 2+ The removal rate is as high as 89.1%.

[0062] Figure 7 The graph shows the change in sulfide concentration during the simulated wastewater treatment process by the mixed bacterial solution of sulfate-reducing bacteria. The removal of heavy metals is related to the formation of sulfides. As shown in the graph, the concentration of sulfides continues to increase during the removal of heavy metals until it stabilizes at 20-25 mg / L.

[0063] Figure 8 The graph shows the change in sulfate concentration during the treatment of simulated wastewater by the mixed bacterial solution of sulfate-reducing bacteria. As can be seen from the graph, the mixed bacterial solution of sulfate-reducing bacteria can reduce the sulfate concentration of simulated wastewater from 5500 mg / L to 3858 mg / L within 53 days, with a removal rate as high as 29.8%.

[0064] Application Example 2 Application Example 2 provides a method for treating acidic wastewater from actual mines using a mixed solution of sulfate-reducing bacteria.

[0065] In Application Example 2, the sulfate-reducing bacteria mixed bacterial solution prepared in Example 1 was used as the research object.

[0066] Acidic wastewater was collected from a mine in Fujian Province. The physicochemical properties of the wastewater are shown in Table 3. The wastewater was treated using a mixed bacterial solution of sulfate-reducing bacteria prepared in Example 1.

[0067] Table 3 Physicochemical properties of acidic wastewater from a mine in Fujian Province

[0068] Take 50 mL of bacterial solution and place it in 500 mL of acidic wastewater. Add 50 g of agricultural waste wood chips as a slow-release carbon source and test the treatment effect of the sulfate-reducing bacteria mixed bacterial solution on the actual wastewater.

[0069] Figure 9 The graph shows the pH change of the sulfate-reducing bacteria mixed bacterial solution during the actual wastewater treatment process. As can be seen from the graph, after 35 days of treatment with the sulfate-reducing bacteria mixed bacterial solution, the pH of the wastewater in Fujian can be increased from 3.52 to 8.42, which effectively improves the pH of the wastewater.

[0070] Figure 10 The effect of mixed bacterial solution of sulfate-reducing bacteria on Fe in actual wastewater treatment process 2+Concentration change graph; As shown in the graph, after 35 days of treatment with mixed bacterial solution of sulfate-reducing bacteria, the Fe concentration in Fujian wastewater decreased. 2+ The concentration decreased from 135.4 mg / L to 0.1 mg / L, with a removal rate of 99.9%, indicating its effectiveness in removing Fe from actual wastewater. 2+ It has excellent removal effect.

[0071] Figure 11 The graph shows the change in sulfate concentration during the treatment of simulated wastewater by the mixed bacterial solution of sulfate-reducing bacteria. As can be seen from the graph, after 35 days of treatment with the mixed bacterial solution of sulfate-reducing bacteria, the sulfate concentration in the wastewater from Fujian can be reduced from 2161.1 mg / L to 457.6 mg / L, with a removal rate of 78.8%.

[0072] The above results indicate that the sulfate-reducing bacteria mixed bacterial solution prepared in this application can be applied to the treatment of acidic wastewater in actual mines.

[0073] Application Example 3-5 Application Example 3-5 provides a method for treating simulated acidic mine wastewater using a mixed solution of sulfate-reducing bacteria.

[0074] The difference between Application Examples 3-5 and Application Example 2 is that the source of the sulfate-reducing bacteria mixed bacterial solution is different, originating from Comparative Examples 1-3 respectively. All other parameters in the above application examples are the same as in Application Example 1.

[0075] Application Comparative Examples 1-3 Comparative Examples 1-3 provide a method for treating simulated acidic mine wastewater using a mixed bacterial solution of sulfate-reducing bacteria.

[0076] The difference between Comparative Examples 1-3 and Application Example 2 is that the source of the sulfate-reducing bacteria mixed bacterial solution is different, originating from Comparative Examples 1-3 respectively. All other parameters of the above comparative examples are the same as those of Application Example 1.

[0077] Test results Table 4 shows the treatment effects of the sulfate-reducing bacteria mixed bacterial solution in Application Examples 2-5 and Comparative Examples 1-3 on simulated acidic mine wastewater; including pH, Fe 2+ Concentration, sulfate concentration.

[0078] Table 4. Treatment effects of simulated acidic mine wastewater in Application Examples 2-5 and Comparative Application Examples 1-3

[0079] Based on the wastewater treatment effects of Examples 1-4 and Comparative Examples 1-3, and Application Examples 2-5 and Comparative Examples 1-3, it can be seen that the pH of the enrichment medium for preparing the sulfate-reducing bacteria mixed bacterial solution in Comparative Example 1 was 5.0, while the contents of sodium lactate and malt extract in the enrichment medium for preparing the sulfate-reducing bacteria mixed bacterial solution in Comparative Examples 2-3 were mismatched, resulting in poor treatment effect of the prepared sulfate-reducing bacteria mixed bacterial solution on acidic wastewater. In contrast, the sulfate-reducing bacteria mixed bacterial solution prepared in Examples 1-4 of this application, by precisely matching the content concentration of each raw material component and controlling the pH to 6.0-7.5, exhibits excellent treatment effect on acidic wastewater.

[0080] By further comparing the wastewater treatment effects in Application Examples 2-3, it can be seen that the treatment effect of the sulfate-reducing bacteria mixed bacterial solution prepared with an enrichment medium of pH 6.0 in Example 2 on acidic wastewater is worse than that of the sulfate-reducing bacteria mixed bacterial solution prepared with an enrichment medium of pH 7.0 in Example 1 on acidic wastewater. Therefore, this application preferably controls the pH of the enrichment medium to 6.8-7.2.

[0081] Further comparison of the wastewater treatment effects in Examples 2 and 4-5 reveals that the sulfate-reducing bacteria mixed culture solution prepared in Example 3 (using 2.5 g / L sodium lactate and 0.07 g / L malt wort as the enrichment medium) and Example 4 (using 3.0 g / L sodium lactate and 0.15 g / L malt wort as the enrichment medium) is less effective at treating acidic wastewater than the sulfate-reducing bacteria mixed culture solution prepared in Example 1 (using 2.6-2.9 g / L sodium lactate and 0.07-0.12 g / L malt wort as the enrichment medium). Therefore, this application preferably controls the concentration of the two raw materials in the enrichment medium to 2.6-2.9 g / L sodium lactate and 0.07-0.12 g / L malt wort.

[0082] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A mixed bacterial solution of sulfate-reducing bacteria for treating acidic wastewater from mines, characterized in that, Specifically, the strains with the following relative abundances include: Bacteroides 28.0-35.0%, Bacillus septicemia 13.0-16.0%, Desulfococcus 8.0-12.0%, Desulfospirillum 2.5-3.6%, DesulfoVibrio 2.0-2.7%, and Sulfide Spirochete 0.9-1.7%.

2. The sulfate-reducing bacteria mixed bacterial solution according to claim 1, characterized in that, Specifically, the strains with the following relative abundances include: Bacteroides 30.0-33.0%, Bacillus septicemia 14.0-15.0%, Desulfococcus 9.0-11.0%, Desulfospirillum 2.7-3.4%, DesulfoVibrio 2.1-2.5%, and Sulfide Spirochete 1.1-1.5%.

3. The sulfate-reducing bacteria mixed bacterial solution according to claim 1, characterized in that, Specifically, the strains with the following relative abundances include: Bacteroides 31.0-33.0%, Bacillus septicemia 14.0-15.0%, Desulfococcus 9.0-10.0%, Desulfospirillum 2.7-3.4%, DesulfoVibrio 2.1-2.5%, Sulfide Spirochete 1.1-1.5%, Acidic Cocci 5.1-8.5%, Riken 2.9-3.8%, Raoultella 2.4-3.5%, Enterobacter 2.1-4.2%, Amniopterus 1.2-2.5%, and Anaerobic Filamentosum 1.1-2.2%.

4. The sulfate-reducing bacteria mixed bacterial solution according to claim 1, characterized in that, Specifically, the strains included in relative abundance were: Bacteroides 30.0-33.0%, Bacillus septicemia 14.0-15.0%, Desulfococcus 9.0-10.0%, Desulfospirillum 2.7-3.4%, DesulfoVibrio 2.1-2.5%, Spirochetes sulfide 1.1-1.5%, Acidococcus 6.1-7.0%, Riken 3.0-3.5%, Raoultella 2.8-3.2%, Enterobacter 2.1-2.8%, Amniporium 1.6-2.0%, Anaerobic filaments 1.5-2.0%, Stylobacterium 1.4-1.8%, Acinetobacter 1.1-1.5%, Clostridium rumenans 0.8-1.2%, and Trichophyton 0.4-0.6%; the remainder being other strains; among the other strains, the content of each strain was <0.5%.

5. A method for preparing a mixed bacterial suspension of sulfate-reducing bacteria as described in any one of claims 1-4, characterized in that, Specifically, the following steps are performed sequentially: Collect sediment samples from acidic mine wastewater; place the sediment samples in an enrichment culture medium at a ratio of 18-22g: 800-1200mL, and enrich them for 37-43 days under dark and normal temperature conditions to obtain an enriched bacterial solution, which is a mixed bacterial solution of sulfate-reducing bacteria. The enrichment medium comprises the following components at the following concentrations: KH₂PO₄ 0.6-0.8 g / L, NH₄Cl 1.3-1.5 g / L, CaCl₂·6H₂O 0.15-0.20 g / L, MgSO₄·7H₂O 2.4-2.8 g / L, Na₂SO₄ 0.8-1.2 g / L, yeast extract 0.4-0.6 g / L, sodium lactate 2.5-3.0 g / L, and malt extract 0.05-0.15 g / L. The pH of the enrichment medium is 6.0-7.

5.

6. The method for preparing the sulfate-reducing bacteria mixed bacterial solution according to claim 5, characterized in that, The enrichment medium comprises the following components at the following concentrations: KH₂PO₄ 0.65-0.78 g / L, NH₄Cl 1.3-1.5 g / L, CaCl₂·6H₂O 0.15-0.20 g / L, MgSO₄·7H₂O 2.5-2.7 g / L, Na₂SO₄ 0.8-1.2 g / L, yeast extract 0.4-0.6 g / L, sodium lactate 2.6-2.9 g / L, and malt extract 0.07-0.12 g / L. The pH of the enrichment medium is 6.8-7.

2.

7. The method for preparing the sulfate-reducing bacteria mixed bacterial solution according to claim 5, characterized in that, It also includes subculturing the enriched bacterial solution; the subculturing method is as follows: the enriched bacterial solution is transferred to an improved culture medium at a ratio of 8-12 mL: 80-120 mL, and subcultured once every 12-15 days under dark and room temperature conditions; the improved culture medium includes the following components at the following concentrations: Na2SO4 0.8-1.2 g / L, yeast extract 0.4-0.6 g / L, sodium lactate 0.5-0.9 g / L, malt extract 0.05-0.15 g / L, and the pH of the improved culture medium is 6.8-7.

2.

8. The method for preparing the sulfate-reducing bacteria mixed bacterial solution according to claim 7, characterized in that, The improved culture medium comprises the following components at the following concentrations: Na2SO4 0.8-1.2 g / L, yeast extract 0.4-0.6 g / L, sodium lactate 0.6-0.8 g / L, and malt extract 0.07-0.12 g / L, and the pH of the improved culture medium is 6.8-7.

2.

9. The application of the sulfate-reducing bacteria mixed bacterial solution as described in any one of claims 1-4 or the sulfate-reducing bacteria mixed bacterial solution prepared by the preparation method as described in any one of claims 5-8 in the treatment of acidic wastewater from mines.

10. A method for treating acidic wastewater from mines, characterized in that, The sulfate-reducing bacteria mixed solution according to any one of claims 1-4 or the sulfate-reducing bacteria mixed solution prepared by the preparation method according to any one of claims 5-8 is used to treat acidic wastewater from mines.

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