Sulphate reduction in a biological cathode and physically separated from biological organic matter oxidation has been studied in this paper. The bioelectrochemical system was operated as microbial fuel cell (for bioelectricity production) to microbial electrolysis cell (with applied voltage). Sulphate reduction was not observed without applied voltage and only resulted when the cathodic potential was poised at -0.26 V vs. SHE, with a minimum energy requirement of 0.7 V, while maximum removal occurred at 1.4 V applied. The reduction of sulphate led to sulphide production, which was entrapped in the ionic form thanks to the high biocathode pH (i.e. pH of 10) obtained during the process. (C) 2012 Elsevier Ltd. All rights reserved.