Sulphate-Reducing Bacteria

Sulphate Reducing Bacteria (SRB) are ubiquitous in the environment. Sulfate-reducing conditions facilitate the biodegradation of petroleum hydrocarbons as well as chloroform (CF) and carbon tetrachloride (CTC). 

Sulfide radicals produced by SRB and precipitated as iron sulfide can also abiotically degrade TCE and PCE. However, SRB also competes with DHCs for hydrogen and the sulfide radicals they produce are toxic to DHCs. The production of sulfide radicals is unlikely to cause a problem for DHCs established in anaerobic aquifers with incoming flows of sulfates, however, the SRB bloom and sulfide radicals produced following electron donor addition to an aquifer can completely eliminate bioaugmented DHCs. Quantification of SRB provides an understanding of risks to DHC inhibition (via competition for hydrogen and toxic sulfides) and enables optimal timing of bioaugmentation with AusPCE where an aerobic aquifer has been treated for anaerobic reductive dechlorination.