Biotrickling Filtration of Air Contaminated with 1-Butanol

The removal of high concentrations of 1-butanol in an air stream was evaluated with a biotrickling filter for potential application to an industrial off-gas. Experiments were conducted on a laboratory-scale system, packed with perlite, in a co-current downward mode with constant recycling of water. The performance was monitored for different inlet concentrations and empty bed residence times during a period of over 60 days of stable operation. A maximum elimination capacity (EC) of 100 g m−3 h−1 was achieved during periods in which the butanol concentration varied from 0.55 to 4.65 g m−3. The removal efficiency was stable and exceeded 80% for butanol concentrations in the range of 0.4 to 1.2 g m−3, corresponding to inlet mass loadings of up to approximately 100 g m−3 h−1. However, when the concentration exceeded 4 g m−3, removal efficiency rapidly dropped to 15% (EC of 22 g m−3 h−1), indicating an inhibition effect that was reversed by decreasing the inlet concentration. This biotrickling filter was able to deal with higher sustained butanol concentrations than have been previously reported, but might not be suitable for concentrations much in excess of 1.2 g m−3 or mass inlet loads in excess of 100 g m−3 h−1.