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 (q(max)), half saturation constant (K(s)), 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%), Ideo-nella sp. (28%), and Dechloromonas sp. (19%). (C) 2010 Elsevier Ltd. All rights reserved.