Steady- and transient-state H2S biofiltration using expanded schist as packing material

The performances of three laboratory-scale biofilters (BF1, BF2, BF3) packed with expanded schist for H2S removal were studied at different empty bed residence times (EBRT = 35, 24 and 16 s) in terms of elimination capacity (EC) and removal efficiency (RE). BF1 and BF2 were filled with expanded schist while BF3 was filled with both expanded schist and a nutritional material (UP20; 12% vol). BF1 and BF3 were inoculated with activated sludge, whereas BF2 was not inoculated. A maximum EC of 42 g m(-3) h(-1) was recorded for BF3 at EBRT = 35 s demonstrating the ability of schist to treat high H2S loading rates, and the ability of UP20 to improve H2S removal. Michaelis-Menten and Haldane models were fitted to the experimental elimination capacities while biofilter responses to transient-state conditions in terms of removal efficiency during shock load events were also evaluated for BF1 and BF3.