Removal efficiency of high-concentration H2S in a pilot-scale biotrickling filter.

A pilot-scale biotrickling filter (BTF) packed with polyurethane (PU) foam was installed at one pharmaceutical factory in Zhejiang Province to study the removal of high-concentration H2S from water treatment plant. Experiments were performed at different empty bed residence times (EBRTs), H2S input load, ratio of liquid flow rate to gas inlet rate (L/G) and sulfate concentration in recirculating liquid to examine their effects on the performance of the BTF. The performance of this bioreactor was monitored continuously over a period of 56 days. After the start-up within 8 days, H2S removal efficiency remained between 90% and 100% with inlet concentration fluctuating from 238 to 590 mg m(-3). H2S removal efficiency was consistently greater than 90%, even at a short EBRT of 9 s and inlet H2S load higher than 187 g m(-3) h(-1). Profiles over the height of the reactor indicated that H2S removal took place mostly in the first section of the column. The performance of BTF could be maintained at high and stable levels when L/G was below 0.005 and sulfate concentration down to 28 g l(-1). The results led to the conclusion that BTF is the optimal choice for treating high-concentration H2S.