Simultaneous treatment of dimethyl disulfide and hydrogen sulfide in an alkaline biotrickling filter

Foul odors comprise generally a complex mixture of molecules, where reduced sulfur compounds play a key role due to their toxicity and low odor threshold. Previous reports on treating mixtures of sulfur compounds in single biofilters showed that hydrogen sulfide (H₂S) interferes with the removal and degradation of other sulfur compounds. In this study, hydrogen sulfide (H₂S) and dimethyl disulfide (DMDS) were fed to an alkaline biotrickling filter (ABTF) at pH 10, to evaluate the simultaneous removal of inorganic and organic sulfur compounds in a single, basic-pH system. The H₂S-DMDS mixture was treated for more than 200 days, with a gas residence time of 40 s, attaining elimination capacities of 86 g_DMDS m^-3 h^-1 and 17 g_H2S m^-3 h^-1 and removal efficiencies close to 100%. Conversion of H₂S and DMDS to sulfate was generally above 70%. Consumption of sulfide and formaldehyde was verified by respirometry, suggesting the coexistence of both methylotrophic and chemoautotrophic breakdown pathways by the immobilized alkaliphilic biomass. The molecular biology analysis showed that the long-term acclimation of the ABTF led to a great variety of bacteria, predominated by Thioalkalivibrio species, while fungal community was notoriously less diverse and dominated by Fusarium species.