Global Co-occurrence of Acid Mine Drainage and Organic Rich Industrial and Domestic Effluent: Biological sulfate reduction as a co-treatment-option

Biological sulfate reduction offers prospects to co-treat a variety of organic and inorganic waste effluents because of the ability of sulfate reducing bacteria (SRB) to reduce sulfate to sulfide and generating alkalinity while using organic substrates for their metabolism. SRB are found in sulfate rich waters such as acid mine drainage (AMD). AMD does not contain enough organic substrates to sustain SRB metabolism and growth. Commercial grade organic electron donors such as ethanol, lactate and methanol have been used successfully in the treatment of AMD but are costly to sustain long-term treatment of AMD. This calls for the exploration of cheap and locally available organic substrates as alternatives. This study therefore explores utilization of locally available industrial, agricultural and domestic wastewaters in providing organic substrates for sulfate reduction in the treatment of AMD. The study leverages the ability of SRB to use organic substrates while reducing sulfate to hydrogen sulfide. Organic substrates can be removed from the organic rich effluent through sulfate reduction, while the biologically generated hydrogen sulfide can be used to precipitate dissolved metals, biogenic alkalinity attenuates pH, and hence AMD can be made free of sulfate, metals and acidity.