Removal of Methyl Isobutyl Ketone From Contaminated Air by Trickle-Bed Air Biofilter

A laboratory-scale trickle-bed air biofilter was evaluated for the removal of methyl isobutyl ketone (MIBK) from a waste gas stream. Six-millimeter (6  mm) Celite pellets (R-635) were used as the biological attachment medium. Effects of MIBK volumetric loading rates on removal efficiency, biofilter reacclimation, biomass growth, and removal kinetics were studied under three different operating conditions, namely, backwashing and two intermittent periods (off chemical—no MIBK input; and off flow-no flow input). Backwashing of the biofilter once a week with full-medium fluidization removed the excess biomass and attained stable long-term performance with over 99% removal efficiency for loading rates less than 3.26  kg chemical oxygen demand (COD)/m^3  day. The two intermittent periods could also sustain high removal efficiency for loading rates up to 1.09  kg  COD/m^3  day without any backwashing. The recovery time increased with an increase in loading rates. Furthermore, the intermittent operations required a longer time to recover than backwashing. The pseudofirst-order removal rate constant decreased with an increase in volumetric loading rate. The removal kinetics showed an apparent dependency on the experimental operating conditions.