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:SO 4 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:SO 4 ratios, which were 8.1, 11.2 and 15.0. However, the rates of COD removal did differ with influent COD:SO 4 ratios. The percentage sulphate removed decreased as the ratio of COD:SO 4 increased. Not all of the COD was used for sulphate reduction, with only 31% being accounted for.