The effects of perchlorate concentration and hydraulic retention time (HRT) on perchlorate reduction characteristics were investigated in a sulfur-based perchlorate reduction reactor.The results showed that the perchlorate was completely removed at HRT of 12 h and the influent perchlorate concentration ranged from 50 mg·L-1 to 194 mg·L-1;The perchlorate removal efficiency was 74% at HRT of 4 h and the influent perchlorate concentration was 194 mg·L-1;The yield of sulfate was increased by increasing the influent perchlorate concentration and HRT;The influent pH and alkalinity was approximately 8.0 and 500 mg·L-1 CaCO3,and the effluent pH and alkalinity was approximately 6.7 and 100 mg·L-1 CaCO3,respectively;The oxidation reduction potential (ORP) ranged from -380 mV to -330 mV at the bottom of the reactor,however,ORP ranged from -300 mV to -250 mV at the top of the reactor;The molecular biological analysis showed that the microbial consortium structure was different along the flow path in the reactor,Sulfurovum which is known to oxidize sulfur was decreased from 57.78% to 32.19% and Hydrogenophilaceae which is known to oxidize hydrogen sulfide was increased from 4.35% to 22.24%.
Keywords: consortium structure analysis; hydraulic retention time (HRT); oxidation reduction potential (ORP); perchlorate; sulfur autotrophic.