Optimum Study On Sulfate Reducing Bacteria Coated Ore To Control Acid Wastewater Discharge And Carbon Source

Copper is an industry with outstanding competitive advantages in Jiangxi,and the output of copper mines is among the best in the country.The mining scale and output of the mine are getting larger and larger,and accordingly more and more low-grade ores(commonly known as waste rock)are being collectively discarded and deposited in the waste rock mountain.The accumulated waste ore is exposed to the air for a long time.Due to natural oxidation and the leaching of rainwater,a large amount of acidic mine wastewater is generated.Acidic mine wastewater has a low pH and contains large amounts of sulfate ions and heavy metal ions,causing serious pollution to the surrounding environment and groundwater.According to the current research progress,the main methods for treating acid mine wastewater pollution are:traditional physical methods(such as adsorption method),chemical methods(such as acid-base neutralization method),and some special treatment methods(such as constructed wetland method)Wait).However,these methods are difficult to carry out large-scale engineering applications due to the limitations of ore accumulation sites,costs,and scope of application.The microbial treatment method using sulfate-reducing bacteria is currently the most potential method for pollution control of sulfur-containing ores.Therefore,this master's degree thesis intends to conduct research on the use of sulfate-reducing bacteria to control new technologies of acid mine wastewater discharge,by improving the advantages of the preferred sulfate-reducing bacteria in the microbial flora,and exploring the optimal growth of sulfate-reducing bacteria Conditions,such as temperature,pH value,and the effects of different initial sulfate concentrations and different carbon sources on the growth of sulfate-reducing bacteria;then the sulfate-reducing bacteria coated ores were simulated to control the discharge of acid wastewater.The main research contents include;1.Enrichment,purification and identification of sulfate reducing bacteriaIn order to increase the proportion and superiority of sulfate-reducing bacteria in the flora,the sulfate-reducing bacteria were first enriched repeatedly and purified by the dilution coating-stacked sandwich method to obtain the treated experiment Flora.Samples were extracted from the microflora and observed by scanning electron microscopy,and then the 16S rRNA gene sequence was 97%similarity level to classify the OTU statistical flora.The experimental results show that the content of sulfate-reducing bacteria in the flora increased from about 23%to 60%,forming a microbial community with sulfate-reducing bacteria as the dominant species.2.Study on physiological characteristics of sulfate-reducing bacteriaThe physiological characteristics of the enriched and purified flora were studied,the conditions of different initial pH values,different initial temperatures and different initial sulfate concentrations were set,and the growth process of sulfate-reducing bacteria and the changes of relevant parameters in the culture medium were analyzed.Such as OD600,pH and sulfate removal rate.The results showed that the growth of the sulfate-reducing flora after treatment accorded with the S-shaped curve of microbial growth.The optimum pH for the growth of the flora was 7.0,the optimum temperature was 33?,and the initial sulfate concentration was 500 mg/L-2000 mg/At L,the growth of sulfate-reducing bacteria is not inhibited by sulfate concentration.With sufficient carbon source,as the concentration of sulfate increases,the efficiency of sulfate removal also increases.Under the condition that ethanol,sodium lactate,maltodextrin and sludge are respectively carbon sources,sulfate reducing bacteria can use these substances as carbon sources.3.Optimization research on controlling acid wastewater discharge and carbon source by sulfate-reducing bacteria coated oreIn order to explore the application of the sulfate-reducing bacteria biological method in the actual situation,this part of the experiment simulates the field environment and conducts a column leaching experiment to analyze the effect of in-situ control of acid mine wastewater under the action of different carbon sources.The experimental results show that inoculating SRB and supplementing the carbon source in the initial stage can effectively control the sulfate release of sulfur-containing waste rock and the generation of acid mine drainage,using ethanol,maltodextrin,sodium lactate and sludge from urban domestic sewage treatment plants as carbon sources.When leaching into rainwater,the sulfate emission reduction rates were 84.8%,76.2%,69.9%,and 54.0%,respectively.In the experimental column using maltodextrin as the carbon source,due to the strong film-forming or smearing performance of maltodextrin,a dense biofilm can be produced on the surface of the ore.The physical structure of the biofilm itself can inhibit the ore in the air.Leaching oxidation,and more conducive to the retention and sustained role of sulfate reducing bacteria.The predominant bacteria in the biofilm are Proteobacteria,Firmicutes and Bacteroidetes,which can effectively control the oxidation of sulfur and the generation of acid drainage.