This study demonstrates the possibility of removal of dimethyl sulfide in a thermophilic biotrickling filter (BTF52) operated at 52 degrees C, using an enriched sludge inoculum. The efficiency and long-term performance of BTF52 were compared with a reactor operated in parallel at 22 degrees C (BTF22). After a start-up period of 17 and 25 days, maximum elimination capacity values of about 30 and 18 g m h were measured in BTF22 and BTF52. respectively. However, using tap water instead of deionized water as a matrix for the mineral medium caused a substantial improvement of maximum elimination capacity increasing to 75 and 45 g m(-3) h(-1) in BTF22 and BTF52. CaCO3 was found to be the crucial ingredient causing this performance increase. Also, the effect of variable operating conditions on the performance of both reactors was examined. At DMS loading rates of 6.5 g m(-3) h(-1). the elimination capacities in both reactors recovered within 2 h after shor-term (24 and 48 h) complete shut downs. Temperature changes to 21 and 59 degrees C decreased the removal efficiency of BTF52 by 90 and 30%, respectively. Finally, batch experiments showed that liquid-phase sulfate concentrations exceeding 2.2 g L-1, decreased the removal rate by 50% at 52 degrees C. (C) 2007 Elsevier B.V. All rights reserved.