Bioaugmentation of Aerobic Granular Sludge with the Addition of a Bioflocculant-Producing Consortium

Abstract

A consortium of bioflocculant-producing bacteria (BPA), mainly consisting of previously enriched Devosia hwasunensis and Tetrasphaera elongata, was inoculated into a sequencing batch airlift reactor during aerobic granular sludge cultivation to determine the effects of BPA on the formation of aerobic granular sludges. The results indicate that granulation time was substantially shortened from 56 to 28 days with the addition of BPA. Microbial community analysis of granular sludge based on denaturing gradient gel electrophoresis revealed diversity. Dominant populations belonged to Actinobacteria and α-and γ-proteobacteria. The added bacterial species, D. hwasunensis and T. elongata, which have been proposed to secrete extracellular polysaccharide mucus, played an important role in particle formation and in the maintenance of the stability and physicochemical properties of the granular sludge.