title: Simultaneous bio-autotrophic reduction of perchlorate and nitrate in a sulfur packed bed reactor: Kinetics and bacterial community structure.
abstract: This study investigated the simultaneous removal of perchlorate and nitrate from aqueous solution in an up-flow sulfur autotrophic reduction reactor. A nitrate and perchlorate containing pollution solution was treated with a remarkable removal efficiency greater than 97%. The concentration of nitrate was 22.03 ± 1.07 mg-N/L coexisting with perchlorate either 21.87 ± 1.03 mg/L or 471.7 ± 50.3 μg/L, in this case the reactor could be operated at a hydraulic retention time (HRT) ranging from 12.00 h to 0.75 h. Half-order kinetics model fit the experimental data well; this indicates that diffusion in the biofilm was the limiting step. Perchlorate reduction required a longer reaction time than the coexisting nitrate, regardless of the perchlorate concentration. Sulfur (S) disproportionation was inhibited when nitrate was not completely removed; whereas it was accelerated when perchlorate decreased to low concentrations. This process therefore generated excessive sulfate and consumed much more alkalinity. High-throughput sequencing method was used to analyze bacterial community spatial distribution in the reactor under different operational conditions. The reduction of the two contaminants was accompanied by a decrease in biodiversity. The results indicated that Sulfuricella, Sulfuritalea Thiobacillus, and Sulfurimonas are effective DB (denitrification bacteria)/PRB (perchlorate reduction bacteria). The Chlorobaculum genus was the dominant bacteria associated with S disproportionation.
authors.affiliation: School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou, Henan, 450001, China. Electronic address: dongjinwan@yeah.net.
authors.forename: Dongjin
authors.initials: D
authors.lastname: Wan
authors.affiliation: School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou, Henan, 450001, China.
authors.forename: Yongde
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou, Henan, 450001, China.
authors.forename: Yiyi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China. Electronic address: xiaoshuhu@126.net.
authors.forename: Shuhu
authors.initials: S
authors.lastname: Xiao
mesh_terms: D019149:Bioreactors / Q000382:microbiology; D019414:Chlorobi; D007700:Kinetics; D009566:Nitrates / Q000737:chemistry; D010472:Perchlorates; D013455:Sulfur / Q000737:chemistry*; D018508:Water Purification
chemical_list: D009566:Nitrates; D010472:Perchlorates; D013455:Sulfur
keywords: High-throughput sequencing; Kinetics; Nitrate; Perchlorate; Sulfur autotrophic; Sulfur disproportionation