ABSTRACT

44Anaerobic bioconversion of methanol was tested in the presence of selenate (SeO4 2−), thiosulfate (S2O3 2−) and sulfate (SO4 2−) as electron acceptors. Complete SeO4 2− reduction occurred at COD:SeO4 2− ratios of 12 and 30, whereas ~ 83% reduction occurred when the COD:SeO4 2− ratio was 6. Methane production did not occur at the three COD:SeO4 2− ratios investigated. Up to 10.1 and 30.9% of S2O3 2− disproportionated to SO4 2− at COD:S2O3 2− ratios of 1.2 and 2.25, respectively, and > 99% reduction was observed at both ratios. The presence of S2O3 2− lowered the methane production by 73.1% at a COD:S2O3 2− ratio of 1.2 compared to the control. This study showed that biogas production is not preferable for SeO4 2− and S2O3 2− rich effluents such as pulp and paper, and petroleum refining wastewaters, whereas volatile fatty acids (VFA) production could be a potential resource recovery option for these wastewaters.