Effects of concentration and gas flow rate on the removal of gas-phase toluene and xylene mixture in a compost biofilter

The aim of this work was to study the performance of a compost/ceramic bead biofilter (6:4 v/v) for the removal of gas-phase toluene and xylene at different inlet loading rates (ILR). The inlet toluene (or) xylene concentrations were varied from 0.1 to 1.5 g m⁻³, at gas flow rates of 0.024, 0.048 and 0.072 m³ h⁻¹, respectively, corresponding to total ILR varying between 7 and 213 g m⁻³ h⁻¹. Although there was mutual inhibition, xylene removal was severely inhibited by the presence of toluene than toluene removal by the presence of xylene. The biofilter was also exposed to transient variations such as prolonged periods of shutdown (30 days) and shock loads to envisage the response and recuperating ability of the biofilter. The maximum elimination capacity (EC) for toluene and xylene were 29.2 and 16.4 g m⁻³ h⁻¹, respectively, at inlet loads of 53.8 and 43.7 g m⁻³ h⁻¹.