The use of micro-algal biomass as a carbon source for biological sulphate reducing systems

An upflow anaerobic digestor was fed dried algal biomass as a carbon source to establish the feasibility of using micro-algal biomass as the sole carbon source for biological sulphate reduction. The effect of the COD:SO4 ratio on substrate consumption and sulphate removal efficiencies were assessed by varying the organic carbon content of the media. Similar COD removal efficiencies were obtained irrespective of the influent COD:SO4 ratios, which were 8.1, 11.2 and 15.0. However, the rates of COD removal did differ with influent COD:SO4 ratios. The percentage sulphate removed decreased as the ratio of COD:SO4 increased. Not all of the COD was used for sulphate reduction, with only 31% being accounted for.