Comparison between sucrose, ethanol and methanol as carbon and energy sources for biological sulphate reduction

Abstract

Sulphate was reduced via sulphide to sulphur when operating a single-stage completely mixed reactor configuration feeding synthetic feed. The aim of this study was to determine the volumetric and specific sulphate reduction rates using sugar, ethanol and methanol as a carbon and energy sources. The presented results indicated that sugar and ethanol were found to be suitable carbon and energy sources resulting in a volumetric and a specific sulphate reduction rate of 10.4 and 4.8 g SO4(l.d) and 0.8 and 2.8 g SO4/(gVSS.d), respectively, at a Hydraulic Retention Time (HRT) of 3.6 h and at ambient temperature (21 degrees C). Methanol induced methanogenesis rather than sulphidogenesis. The experimental sulphide/sulphate ratio was consistently lower than the theoretical value which indicated that part of the formed sulphide was oxidized to sulphur.