Biofiltration of H2S in air-Experimental comparisons of original packing materials and modeling

The treatment of hydrogen sulfide using a biofilter packed with expanded schist and topped with a layer of a synthetic nutritional material (UP20) was examined at a constant H2S concentration (100 ppmv). The impact of the empty bed residence time (EBRT) on process performances was clearly underlined by varying the polluted air flow from 4 to 20 m(3) h(-1) corresponding to a variation in the EBRT from 63 to 13 s. Complete H2S degradation was observed when the EBRT was higher than 51 s. Experimental data collected at various EBRTs (13-63 s) were fitted using the Ottengraf model equations. The alpha(lump) parameter value was found to be 26.4 g(1/2) m(-3/2) h(-1). This single parameter, which enables the performance of the biofilter as a whole to be characterized whatever its composition (mixture or layers of different packing materials) and whatever the EBRT, is a powerful tool to compare packing materials and to design such bioreactors. Theal alpha(lump) value characterizing the performances of expanded schist coupled with a thin layer of UP20 was higher than thea alpha(lump) values obtained for other packing materials (natural or synthetic) reported in previous studies. (c) 2016 Elsevier B.V. All rights reserved.