ABSTRACT
Laboratory scale experiments were performed to evaluate the feasibility of biofilters for the removal of H[2]S from wastewater treatment plant waste air. The effects of changes in air flow rate and contaminant concentration on biofilter performance treating H[2]S odours were also assessed. Compost was used as media in biofilter. The study was carried out in six different phases, by increasing H[2]S concentrations gradually. In the first phase only humidified air was supplied to acclimatize and develop the biofilm, within the biofilter conditions. In the second phase, inlet H[2]S concentration was kept up to 10 ppm with the humidified air, H-[2]S removal efficiency was very high around 98%. It was concluded that the biofilter, used in the study, was more efficient [>95% removal efficiency] for low contaminant concentrations [up to 30 ppm]. However, as the concentration of H[2]S was increased to 50 ppm the removal efficiency decreased to 85%. The study results showed that biofilter could withstand longer starvation period and required less time to recover to its full efficiency. The effect of operating parameter such as moisture content was also assessed. The study revealed that the compost biofilter may be successfully adopted for various industrial operations where a reduction in emissions of H[2]S is required