Use of mature compost as filter media and the effect of packing depth on hydrogen sulfide removal from composting exhaust gases by biofiltration

A study was conducted to investigate the utilization of mature compost as a biofilter medium for the removal of hydrogen sulfide (H 2 S) from the exhaust gases of the composting process. Source-selected kitchen waste from municipal solid waste was composted in a reactor, and the exhaust gas was passed through a biofilter packed with a 1:4 (wet weight) mixture of mature compost and sand. Two treatments were applied under sterilized and unsterilized conditions to quantify the contribution of microbial activity. The effect of packing depth on H 2 S removal efficiency was also studied. A global H 2 S removal efficiency of 51% was obtained in the biofilter for loading rates in the range of 0–429 mg H 2 S m −3 h −1 . The adsorption capacity was the main factor affecting H 2 S removal efficiency, contributing 64.2% to the total removal efficiency, with microbial activity contributing 35.8%. The relationship between the cumulative amount of H 2 S removed and the packing height was well-described by a linear equation. The equation indicated that 99% H 2 S removal efficiency could be achieved using a packing height of 96 cm for unsterilized packing material or 158 cm for sterilized packing material.