BACKGROUND: An alkaline mineral medium (pH approximate to 10) was used in a previous study to enhance the absorption rate of hydrogen sulfide in a biofiltration process where an alkaliphilic sulfo-oxidizing bacterial consortium was deployed. In this work the same mineral media and bacterial consortium were used to assess a biotrickling filter performance during the treatment of low gaseous concentrations of carbon disulfide and ethanethiol. RESULTS: The alkalinity of the mineral medium increased the solubility of carbon disulfide and ethanethiol by around 50% and 80%, respectively. The oxidation activity of the microorganisms resulted in a lower value compared to other reported results. The maximum elimination capacities reached using alkaline biotrickling filtration were between 2.3 and 3.5 g m(-3) h(-1) with removal efficiencies around 50%. A conceptual model for biotrickling filtration of ethanethiol was developed and validated using experimental data under dynamic conditions. CONCLUSION: Alkaline conditions enhance the absorption rates of sulfur compounds in a biotrickling filter, but the elimination capacity of the system was limited by the low oxidation activities of the alkaliphilic microorganisms. It is necessary to continue exploring the biodiversity in order to find a microorganism adapted to the consumption of volatile sulfur compounds. (C) 2010 Society of Chemical Industry