ABSTRACT
Dissimilatory sulfate reduction is a microbial process that commonly occurs in anoxic aquatic environments. By-products of the process are hydrogen sulfide and carbonate alkalinity. Sulfate reduction in wetlands constructed to treat acid mine drainage (AMD) is desirable because hydrogen sulfide readily reacts with dissolved metals, precipitating them as sulfides, and alkalinity neutralizes drainage acidity. This chapter discusses factors which affect the importance of sulfide formation in aquatic systems and evaluates the theoretical potential of the process in wetlands constructed to treat AMD. The importance of dissimilatory sulfate reduction (DSR) in affecting the chemistry of flow-through water is related to the difference between rates of formation and destruction of sulfides. The plan calls for the acid inflow to be partially neutralized by the limestone, subjected to DSR processes as it diffuses upward through the organic substrate, and subjected to oxidizing, “polishing” processes at the wetland surface.
