Bioremediation of Mine tailings from Chhattisgarh, India

Abstract

Mining activity for extraction of the underground minerals for industrial operation and economic growth of a country is inevitable. After successful extraction of the minerals, the fine dumping contents termed as mine tailings (MT) with scattered traces of residual minerals, dig up the soil, and a disturbed ecosystem is left unattended and often without any treatment. This leads to serious threats to the surrounding ecosystems due to the presence of various toxic, primary and secondary elements in the form of organic/inorganic pollutants. In the present study, we considered MTs from three mining sites, namely, Nandini Limestone Mine, Limestone Century Cement Mine and Dalli Rajhara Iron Mine located in Chhattisgarh, India. Lead and iron along with sulfate are detected at high concentrations from the three sites. The laboratory acclimatized culture mixed with fresh MTs at four ratios (3:1, 2:1, 1:1 and 1:2) are exposed to three different environments, namely, anaerobic, anoxic and aerobic for determining the treatment potential. Microbial study confirms the presence of iron resistant microbial species namely, Bacillus cereus, Bacillus megaterium, Bordetella ansorpi and Sinorhizobium meliloti as well as lead resistance possessing microbes Bacillus thuringiensis, Clostridium perfringens, Escherichia coli and Bacillus amyloliquefaciens in the acclimatized reactor originated from MTs. Lead and iron resistant species are identified in all the sites capable of MTs treatment and at the ratio of 3:1, 2:1, 1:1 all the reactors provided similar performance, whereas there is a drop in performance efficiency of all the reactors at the ratio of 2:1. Therefore, with acclimatized indigenous culture, bioremediation of MTs rich in lead and iron is feasible in all three environments.