Performance of a compost and biochar packed biofilter for gas-phase hydrogen sulfide removal

The main aim of this study was to evaluate the performance of an aerobic biofilter packed with compost for the removal of gas-phase hydrogen sulfide (H2S). After 52 d of operation, the biofilter was re-packed by replacing a certain portion (25%, v/v) of the existing compost with biochar and its performance was tested. The steady and transient performance of the biofilter was evaluated by varying the H2S concentrations from 0.1 to 2.9 gm(-3) at an empty bed residence time (EBRT) of 119 and 80s, respectively. The maximum elimination capacity (ECmax) of the compost and compost + biochar biofilter were similar to 19 and 33 gm(-3) h(-1), respectively, with > 99% removal efficiency at an EBRT of 119s. The compost biofilter showed a quick response to shock loads and the critical load to the biofilter during the shock loading step was similar to 81 gm(-3) h(-1).