Evaluation of innovative packing materials for the biodegradation of H 2 S: a comparative study

The biofiltration of gas polluted with H 2 S was carried out using innovative configurations of packing materials (i.e. a new synthetic material called UP20, sapwood, peat, pozzolan and pine bark). A comparison of seven different configurations (media alone or in combination) was made based on biofilter performances and pressure drop measurements. Biofilters were operated continuously for at least 95 days at a constant flow rate (0.5 N m 3 h −1 corresponding to a superficial velocity of 65 m h −1 and an empty bed residence time of 57 s). Elimination capacities and removal efficiencies were calculated according to loading rates varying from 0 to 25.5 g m −3 h −1 (inlet concentration up to 400 mg m −3 ). Biofilter performances were modelled and biokinetic constants were calculated using the Ottengraf model and a modified Michaelis–Menten model. In terms of elimination capacity, packing materials can be ordered from the most efficient to the least efficient: peat–UP20 in a mixture > peat–UP20 in two layers > peat > pozzolan–UP20 in two layers > pine bark > sapwood–UP20 in two layers > sapwood. A maximal removal rate, V m , of 55 g m −3 h −1 was calculated for biofilters filled with peat–UP20 (in a mixture or in two layers) and peat (in comparison, V m = 8.3 g m −3 h −1 for a biofilter filled with sapwood). Peat is the best material to treat high H 2 S concentrations and the addition of UP20 can significantly increase the removal efficiency. The pozzolan–UP20 combination represents an interesting packing material to treat pollutant loading rates up to 5 g m −3 h −1 with low pressure drops. For low H 2 S concentrations, sapwood can be considered as a good support for H 2 S degradation with pollutant loading rates up to 4 g m −3 h −1 . Copyright © 2010 Society of Chemical Industry