Performance evaluation of an agro waste based biofilter treating toluene vapours

Biodegradation of toluene vapour was investigated for 162 days in a laboratory scale biofilter packed with maize waste. Inlet concentration of toluene was varied from 2.86 to 5.79 g m(-3) and the volumetric flow rate of toluene loaded air from 0.09 to 0.3 m3 h(-1). The media bed height used in the study was 0.63 m. Plug flow behaviour of the bed was confirmed by RTD experiments. The steady state was achieved in 18 days. Depending upon initial loading rates, removal efficiency ranging from 54.5 to 85.3% and elimination capacity ranging from 43.47 to 174.6 g h(-1) m(-3) were observed during steady state operation. The dynamic behaviour of the biofilter was evident from response to change in process conditions. The stability of the biomass was evident from the fast response of the biofilter to shutdown and restart operations. High value of carbon recovery confirms the effective biodegradation in the biofilter. In the startup period, the pressure drop in the bed increased for some time after that it tended towards a constant value.