The performance of a trickle-bed air biofilter (TBAB) for treating butyl acetate (BA) vapour was evaluated under different influent concentrations and gas flow rates. Almost complete BA removal could be achieved for influent carbon loading between 12 and 177 g m(-3) h(-1). The TBAB appeared to be efficient for controlling BA emission under these carbon loading conditions. The applicable conditions of TBAB were thus suggested. A mathematical model that incorporates mass transfer process and biofilm reactions was Presented to predict the performance of TBAB for BA removal. The effluent gas phase BA concentrations predicted by the model were in good agreement with the measured data. In a sensitivity analysis, three parameters were identified to strongly influence the model performance, the surface area of the biofilm per unit volume of packing material (As), the empty-bed residence time (EBRT), and the microbial yield coefficient on BA (Y-B). A practical application of the model to derive the performance equation of TBAB is also given. (C) 2003 Elsevier Ltd. All rights reserved.