The kinetic process of formaldehyde biodegradation in a biofilter packed with a mixture of compost, vermiculite powder and ceramic particles was investigated in this study The results showed that more than 60% of formaldehyde was removed by the first 5 cm high biofilter bed at 406 L h(-1) flowrate within the range of 5-207 mg m(-3) inlet concentrations. A macrokinetic model was applied to describe the kinetic process of formaldehyde biodegradation and the experimentally determined elimination capacity for the biofilter agreed well with the model predicted values The data on the effect of spider plant (Chlorophytum comosum L.) on formaldehyde removal indicated that formaldehyde biofiltration might be stimulated by spider plant since formaldehyde was assimilated by spider plant roots and microbial formaldehyde degradation was enhanced by the root exudates (C) 2010 Elsevier Ltd. All rights reserved