Biofiltration for removal of methyl isobutyl ketone (MIBK): experimental studies and kinetic modelling.

The present study deals with the biofiltration of methyl isobutyl ketone (MIBK), which is considered to be a highly toxic volatile organic compound. It is released from the paint and petrochemical industries and is one of the major contributors to air pollution. The biofiltration study was carried out on a lab scale for two months in the presence of acclimated mixed culture. The performance of the biofilter column was evaluated for different inlet loads of MIBK at air flow rates ranging from 0.18 to 0.3 m3 h(-1). The maximum removal efficiency of 93% was obtained after 60 days of biofilter operation for an inlet MIBK concentration of 0.45 g m(-3), and a microbial concentration of 2.36 x 10(8) CFU g(-1) of packing material was obtained. This led to a study of shock loadings for 20 days, by varying the inlet MIBK load and air flow rate after every five days, to observe the behaviour of the biofilter column in removing sudden loads of MIBK. The biokinetic constants r(max) and Ks were obtained using the Michaelis-Menten kinetics and were found to be 1.046 g m(-3) and 0.115 g m(-3) h(-1),respectively, with a coefficient of determination (R2) of 0.993. The obtained experimental results were validated with the Ottengraf and Van den Oever kinetic model. The critical inlet concentration, critical inlet load and biofilm thickness were also estimated using the results obtained from the model predictions.