The hexane removal performance of three compost-based biofilters containing silicone oil at 0% (control), 10% and 20% v/v, and inoculated with a hydrophobic hexane degrading consortium was comparatively assessed under different irrigation strategies. The addition of 10% of silicone oil to the biofilter significantly improved its abatement performance by 72% compared to the control biofilter. However, when 20% of silicone oil was added to the compost no removal enhancement was observed, likely due to a severe reduction of the water holding capacity of the packing media (which decreased by 71%) together with a silicone-oil mediated gas flow channeling. An optimum mineral salt medium irrigation rate of 100 mL L-packing(-1) d(-1) resulted in a superior and more stable hexane abatement performance. No significant losses of silicone oil were observed at the end of the experimental period (<= 2.5%). (C) 2013 Elsevier B.V. All rights reserved.