Chao Wu
College of Chemical and Biological Engineering, Zhejiang University, China
Biotrickling filter (BTF) applications in two-liquid phase bioreactors (TLPB) are limited by the lack of agitation, ozone clogging in the long term and a further promotion in mass transfer. Versus a twoliquid phase BTF with silicone oil as a non-aqueous phase, a two-liquid phase airlift bioreactor (ALR) was developed to remove gaseous o-xylene. A higher elimination capacity of 26% was obtained for the two-liquid phase ALR (92 g.m-3.h-1, removal efficiency of 91%) versus the two-liquid phase BTF. Removal efficiency of the two-liquid phase ALR was constant and above 90% regardless of the inlet concentration. More complete removal of o-xylene was observed for the two-liquid phase ALR under both steady state and shock-load conditions. Therefore, sufficient mixing is essential to the TLPBs for the removal of hydrophobic VOCs. However, microbial diversity in the two-liquid phase ALR was not richer than that of the two-liquid phase BTF. The dominant microbial community was Comamonas in the two-liquid phase ALR, Chitinophagaceae in the two-liquid phase BTF.
Keywords: Two-liquid phase bioreactor; airlift bioreactor; biotrickling filter; hydrophobic volatile organic compounds; and microbial diversity.