| Acid Mineral Drainage(AMD) as a kind of wastewater of low pH value and high concentration sulphate contains a certain soluble heavy metal ion. If AMD discharges directly into water without effective treatment it will do great harm to the environment. Recently, the two main treatment methods are neutralization and artificial wetland. Neutralization is a method of adding alkaline substance to the wastewater. However, it is difficult to dehydrate and easily causes secondary pollution since a large amount of sludge has been produced. Another method is about artificial wetland, which limited its engineering application in that the plants are fragile on acid resistance as well as its system is not affected. Based on preliminary laboratory work, this paper focused on the cultivation of acid resistance domestication and carrier immobilization, then used self-manufactured anaerobic reactor to deal with acid mineral drainage and made a preliminary evaluation of main indicators on treated wastewater.SRB domestication: the paper made a dynamic study of sulphate degradation process on the basis of gradually reducing the pH of the culture medium to respectively domesticate SRB, and also made a comparative analysis of the variation of pH value and sulphate concentration. The results indicate that SRB could grow under the condition of pH 4, the removal rate of sulphate could reach 15% after domestication and after passage the removal rate of sulphate could reach 38%. However, SRB could not grow under the condition of pH 4 without domestication as well as the removal rate of sulphate is only 0.9%. It shows that domestication process has a significant impact on the growth capacity of SRB’s tolerance to low pH, which plays a key role in the subsequent treatment of AMD by SRB, and meanwhile by the analysis of degradation rate, sulphate degradation model is constructed.Manufacturing process and characteristics: reactor, which was divided into three stages, was made of PVC pipe. Potassium chloride solution was used as tracer, through the variation of conductivity and dissolved oxygen, to study whether the filler had an impact on HRT or not and nitrogen stirring to the residence time of tracer, and then studied the hydraulic hybrid in the reactor. The results show that the multi-stage reactor could meet the anaerobic environment for its internal structure is conducive to strengthening the degree of turbulence inside the reactor and improving the SRB contact with AMD. Each stage of the reactor presents completely mixed flow state, and the overall direction of flow exhibits plug flow pattern. The larger the HRT is, the more fully mixing within the reactor. It leads to detention area or dead zones when the reactor is added with filler. Nitrogen is bubbled into reactor, which enhances the effect on plug-flow and is advantageous to the mixing of fluid in the reactor.Operation of reactors: using two identical reactors to test whether the filler existed and made a research on the impact of hydraulic retention time to the treatment effect. The monitoring results of wastewater indicators show that the optimum HRT of reactor is 20 h when the effect on treatment is best. The pH could increase from 4.5 to about 6.8; the removal rate of sulfate reaches 95.17%; the removal rate of Cu2+ is 92.86%; the removal rate of Fe3+ is 96.51%; and the removal rate of Mn2+ is 95.5%. |
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