Microbial treatment of high-strength perchlorate wastewater

To treat wastewater containing high concentrations of perchlorate, a perchlorate reducing-bacterial consortium was obtained by enrichment culture grown on high-strength perchlorate (1200 mg L−1) feed medium, and was characterized in a sequence batch reactor (SBR) over a long-time operation. The consortium removed perchlorate in the SBR with high reduction rates (35–90 mg L−1 h−1) and stable removal efficiency over 200-day operations. The maximum specific perchlorate reduction rate (qmax), half saturation constant (Ks), and optimal pH range were 0.67 mg-perchlorate mg-dry cell weight−1 h−1, 193.8 mg-perchlorate L−1, and pH 7–9, respectively. The perchlorate reduction yield was 0.48 mol-perchlorate mol-acetate−1. A clone library prepared using the amplicons of cld gene encoding chlorate dismutase showed that the dominant (per)chlorate reducing bacteria in the consortium were Dechlorosoma sp. (53%), Ideonella sp. (28%), and Dechloromonas sp. (19%).