Evaluation of innovative packing materials for the biodegradation of H2S: a comparative study

Abstract

AbstractThe biofiltration of gas polluted with H2S 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 m3 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, Vm, 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, Vm = 8.3 g m−3 h−1 for a biofilter filled with sapwood). Peat is the best material to treat high H2S 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 H2S concentrations, sapwood can be considered as a good support for H2S degradation with pollutant loading rates up to 4 g m−3 h−1. Copyright © 2010 Society of Chemical Industry