Removal of dimethyl sulfide from waste air in a membrane bioreactor

Long-term experiments with a membrane bioreactor to remove dimethyl sulfide (Me2S) from waste air are reported for the first time. The membrane bioreactor contained a polydimethylsiloxane/Zirfon((R)) composite membrane and was inoculated with Hyphomicrobium VS, a methylotrophic micro-organism. The optimal conditions of pH (67) and sulfate contents (< 8 g SO42--S.L-1) for maximum Me2S-degradation were determined in batch studies and applied during membrane biofiltration. Dimethyl sulfide conversion depended both on gas residence time and inlet concentration. The removal efficiency of air contaminated with 38 mg Me2S.m(-3) was found to be 99% at 24 s, 90% at 12 s and 85% at 8 s gas residence time. At a gas residence time of 24 s, removal efficiencies of 99%, 93% and maximum 87% were observed for Me2S concentrations of 33 mg.m(-3), 116 mg.m(-3) and 375 mg.m(-3), respectively. The maximum elimination capacity was 4.82 kg Me2S.m(r)(-3).d(-1) (efficiency of 74%) which is higher than ever obtained with the conventional biofilters and biotrickling filters.