This study armed to develop a biotrickling biofilter packed only with fern chips for the removal of air-borne low concentration VOCs (volatile organic compounds) emitted from a solvent refinery located in Kaohsiung county of southern Taiwan. The fern chips could avoid the shortcomings of traditional media, such as compaction, drying, and breakdown, which lead to the performance failure of the biofilters. A pilot-scale biofilter (0.80 mL ¡Ñ 0.75 mW ¡Ñ 1.50 mH) packed with 0.24 m3 fern chips was used for the performance study. The study was conducted in the plant by drawing vented gas streams from two distillation columns and two solvent storage vessels. The gas streams contain aromatics and oxygenated hydrocarbons such as benzene, alcohols, and esters. Results indicated that suitable nutrition rates are 10, 100, and 10 g/m3.d, respectively, of milk powder, Urea-N, and K2HPO4-P, accompanied with a water spraying rate of 125 L/m3.d. Around 85% of VOCs in the influent gas with concentrations of 600-3,200 ppm (as CH4) could be removed under an average loading of 60 g VOC (as methane)/m3.h. A test indicated that odor intensity (expressed as dilution to threshold (D/T) ratio) of the influent gas could be reduced from around 7,330 to 73.