Comparison of single‐layer and multi‐layer rotating drum biofilters for VOC removal

Abstract

AbstractTwo types of rotating drum biofilters were tested to investigate the effect of medium configuration on biofilter performance for removing volatile organic compounds (VOCs) from waste gas streams. One was a single‐layer biofilter that consisted of a thick layer of open‐pore reticulated polyurethane foam media. The other was a multi‐layer biofilter that used a set of four concentric thinner layers of the media. The effect of the two different media configurations was examined using diethyl ether as a model VOC at various organic loading rates. The results showed that the multi‐layer biofilter could maintain more stable and higher ether removal efficiencies at gas empty bed contact time (EBCT) of 30 s than the single‐layer biofilter at gas EBCT of 90 s, and at organic loading rates ranging from 2.0 to 8.0 kg COD m−3 day−1 (32.1 to 128.4 g ether m−3 h−1), all based on the medium volume. The multi‐layer biofilter also exhibited a more even biomass distribution on the concentric surface at a medium depth than the single‐layer biofilter, which suggests a reduced possibility of short‐circuiting of gas streams and, consequently, better performance.