Effects of sulphate addition and sulphide inhibition on microbial fuel cells

The effects of adding sulphate in: (i) standard activated sludge microbial fuel cells (MFCs) and (ii) larger-scale leachate-treating columns – both as individual units and as a system connected in cascade – are reported. S-replete power output was ∼2-fold higher than that of the S-deplete MFC. Furthermore, the effects of evolved sulphide (S2−) inhibition were investigated. The overall decrease in power output from the sulphide inhibitor (Na2MoO4) additions was 83% for the S-replete and 90% for the S-deplete. The second phase with the leachate treating units shows an improvement of 32–86% (depended on leachate strength) in current output as a result of adding sulphate. When leachate column MFCs were connected fluidically in series, the amount of Na2SO4 made available downstream was decreasing (increase in power was 99%, 40% and 12% for columns in cascade). Results demonstrated the beneficial effects of added sulphur sources to both activated sludge and leachate-treating MFCs.