COAL-GENERATED ACID MINE DRAINAGE REMEDIATION OPTIONS

Acid mine drainage (AMD) causes negative impacts on terrestrial ecosystems, surface and groundwater as well as soils and sediments. In the Midwestern U.S., AMD have primarily been associated with coal mining activity, which has left a legacy of impacted sites that are often remote and disperse, and many are abandoned. They are producing drainages that are acidic and have high contents of sulfate, iron, aluminum and other environmentally relevant metals (i.e., Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn). Adopting effective methods for AMD prevention, treatment and remediation to the point of meeting the surface water quality standards has proved challenging because of the extreme geochemical characteristics of certain coal-generated AMD.

Preventing the formation of coalmine AMD is a desirable approach. Our team has examined alternative coal processing waste disposal technology, such as co-disposal of coarse and fine coal refuse, which can provide both the geotechnical stability needed to lower refuse facility liabilities and the geochemical environment necessary to minimize sulfate and chloride discharges. Bioremediation technologies are based on enhancing the activity of selected microbial communities in order to generate alkalinity and promote reduction reactions of sulfate and metals with subsequent precipitation of sulfide minerals. Recent field and laboratory investigations by our team have shown that a combination of geochemical (i.e., selection of appropriate electron donors for microbial activity) and microbial (i.e, acidophilic and acidotolerant sulfate-reducing bacteria) constituents partially control the long-term AMD remediation efficiency.

In this presentation we will cover the current abiotic and biological strategies for AMD prevention and remediation and discuss the factors that may influence the selection of a certain AMD treatment approach.