Start-up and long-term performance of a gas phase biofilter packed with an inert carrier

Several parameters affecting the performance and characteristics of alkylbenzene fed biofilters were checked when using perlite as inert carrier material. The influence of the inoculum on startup and long term performance was studied using both non defined as well as defined cultures. The inoculated pure cultures, which were still detected in the biofilter after several months operation, allowed shortening the start-up period Qualitative and quantitative biomass distribution appeared to be uneven along the biofilter bed in long term operation studies. The biofilter could withstand a drying period of several weeks although such operating condition led to a shift in dominant microbial populations in the biofilm which was followed by an increase of the biofilter performance. Although a water content of 55-60% appeared to be optimal with perlite, peformance data were still satisfactory down to a water content around 35-40%.