Control of Heavy Metals Contamination from Coal Wastes through Microbial Sulfate Reduction Process

摘要

Acid-mine drainage (AMD) that releases highly acidic, sulfate, and metals-rich drainage is a serious environmental problem, contaminating surface and groundwater as well as soils in coal mining districts in China. This paper presents a laboratory investigation to study the possibility of using sulfate-reducing bacteria (SRB) for inhibiting AMD and controlling heavy metals contamination from coal wastes, which is considered to be the major environmental pollution associated with coal mining activities. Tests were conducted to determine if the bacteria produced hydrogen sulfide could be used for the removal of soluble heavy metals of AMD from coal wastes. We investigated the mechanisms of heavy metals ions precipitation in the form of sulfides from the coal waste by sulfate-reducing bacteria. We investigated the effect of the dosage of SRB inoculation on controlling heavy metals contamination. The results show that SRB can effectively immobilize cadmium and zinc of AMD from coal waste, increase pH value and decrease Eh, EC and SO4 2- concentrations of AMD from coal wastes. The SRB can effectively control heavy metals (Cd and Zn) contamination and AMD from coal wastes.