In this study, the biochemical kinetic behaviors of ketone compounds in a composite bead biofilter were investigated. Both microbial growth rate k(g) and biochemical reaction rate k(d) would be inhibited at higher average inlet concentration. For the microbial growth process, the inhibitive effect was the least pronounced for acetone and the order of k(g) value was MEK > MIPK > acetone in the average inlet concentration range of 100-150 ppm. The degree of inhibitive effect was almost the same for three ketone compounds and the order of k(g) value was acetone > MEK > MIPK in the average inlet concentration range of 200-300 ppm. The values of half-saturation constant K-s for acetone, MEK and MIPK were 26.80, 21.56 and 22.96 ppm, respectively. The values of maximum reaction rate V-m for acetone, MEK and MIPK were 8.55, 9.06 and 7.55 g-C/h-kg packed material, respectively. The zero-order kinetic with the diffusion rate limitation could be regarded as the most adequate biochemical reaction model. For the biochemical reaction process, the inhibitive effect was the most pronounced for MEK and the order of k(d) value was MEK > acetone > MIPK in the average inlet concentration range of 100-150 ppm. The degree of inhibitive effect was MIPK > MEK > acetone and the order of k(d) value was acetone > MEK > MIPK in the average inlet concentration range of 200-300 ppm. The maximum elimination capacity of acetone, MEK and MIPK were 0.157, 0.127 and 0.101 g-C/h-kg packed material. (C) 2007 Elsevier Ltd. All rights reserved.