Rotating Biological Contactors

The Rotating Biological Contactor (RBC) is an effective combination of both biofilter and biotrickling filter which has several advantages. The characteristics and performance of a RBC modified for waste gas treatment are described. Its efficiency was evaluated for the biodegradation of dichloromethane (DCM) in gas phase and benzene and xylene in liquid phase, with specifically acclimated microbial cultures under different hydraulic and organic loading regimes. The gas phase DCM removal (30-80%) is significantly influenced by the organic loading rate and the flow rate, with high initial concentrations and high flow rates giving lower removals. Poor contact with biofilm and inhibition of microbial activity due to acidic intermediates cause reduced removals. High benzene and xylene removals (93-99%) are observed in liquid phase, for inlet TOC ranging between 90 and 1800 mg/l. The microbial profile of the biofilm degrading benzene and xylene was analyzed from the DNA extracted from the biofilm using molecular biological techniques. Phylogenetic analysis revealed nine strains belonging to the phylum Firmicutes and Proteobacteria. © 2013 John Wiley & Sons, Ltd.