Executive Summary : | The mining industry currently deals with continuous high pressures from environmental minds to evolve toward sustainable mining policies. The most important of these aqueous wastes is commonly known as acid mine drainage (AMD). AMD is the result of the exposure of sulfide minerals to oxygen, water and microorganisms. Despite being a natural process, mining activities accelerate its generation causing severe environmental impacts, particularly on soil, water resources and aquatic communities. Such waters typically pose an additional risk to the environment by the fact that they often contain elevated concentrations of metals (iron, aluminium and manganese, and possibly other heavy metals) and metalloids. Another important consideration here is the potential long-term pollution problem, as production of AMD may continue for many years after mines are closed and tailing dams are decommissioned. Acid mine drainage if not adequately managed the environmental degradation could be accelerated. Therefore, mitigation techniques need to be developed and implemented at the mining sites. Additionally, the possibility of recovery of valuable metals from AMD and mining waste is a potential option since not only environmental impact is reduced but also economic advantages can be obtained. Many methods are in use to remediate AMD, but are limited in implementation due to poor performance, design inaccuracies, difficult understanding of the functionality, high costs, usage of hazardous chemicals, depletion of natural resources and the generation of further waste. Bioremediation provides green, safe, and reliable technology for pollutant clean-up, removal, de-pollution, remediation and reclamation of contaminated sites by microbial activities. The proposed research will focus on lab-scale studies for microbial remediation, using bacteria and/or their metabolites, of AMD-impacted soil and water samples from the lignite mines (namely Rajpardi, Tadkeshwar, Panandro etc.) of Gujarat. Recovery of valuable soluble metals such as iron as by-products and sorption of remaining metal pollutants from mine-impacted water using water hyacinth and microbial biomass will also be carried out. The treated water may be utilized for irrigational purposes after evaluation of its toxicity. The developed system will also be evaluated based on its cost-effectiveness. This project aims to provide strategic framework for the environmentally sustainable development of the lignite mining areas and to improve the understanding of the remediation of AMD-impacted soil and water using an eco-friendly and economic microbial strategy. The cost of remediation will be reduced to a certain extent by the recovery of selected valuable metals and the reuse of treated water for irrigational purposes. This research will also pave way for the conservation of the environment in the mining area, and to safeguard the interests of the stakeholders from metal pollution generated through acid mine drainage. |