title: Evaluation of drinking water treatment combined filter backwash water recycling technology based on comet and micronucleus assay.
abstract: Based on the fact that recycling of combined filter backwash water (CFBW) directly to drinking water treatment plants (WTP) is considered to be a feasible method to enhance pollutant removal efficiency, we were motivated to evaluate the genotoxicity of water samples from two pilot-scale drinking water treatment systems, one with recycling of combined backwash water, the other one with a conventional process. An integrated approach of the comet and micronucleus (MN) assays was used with zebrafish (Danio rerio) to investigate the water genotoxicity in this study. The total organic carbon (TOC), dissolved organic carbon (DOC), and trihalomethane formation potential (THMFP), of the recycling process were lower than that of the conventional process. All the results showed that there was no statistically significant difference (P>0.05) between the conventional and recycling processes, and indicated that the genotoxicity of water samples from the recycling process did not accumulate in 15 day continuous recycling trial. It was worth noting that there was correlation between the concentrations of TOC, DOC, UV254, and THMFPs in water and the DNA damage score, with corresponding R(2) values of 0.68, 0.63, 0.28, and 0.64. Nevertheless, both DNA strand breaks and MN frequency of all water samples after disinfection were higher than that of water samples from the two treatment units, which meant that the disinfection by-products (DBPs) formed by disinfection could increase the DNA damage. Both the comet and MN tests suggest that the recycling process did not increase the genotoxicity risk, compared to the traditional process.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China. Electronic address: chentinghit@163.com.
authors.forename: Ting
authors.initials: T
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China. Electronic address: xuyongpeng@hit.edu.cn.
authors.forename: Yongpeng
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Zhiquan
authors.initials: Z
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Shijun
authors.initials: S
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Wenxin
authors.initials: W
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China. Electronic address: hit_cuifuyi@hotmail.com.
authors.forename: Fuyi
authors.initials: F
authors.lastname: Cui
mesh_terms: D004202:Disinfectants / Q000032:analysis; D004203:Disinfection; D060766:Drinking Water / Q000737:chemistry*; D005374:Filtration; D015162:Micronucleus Tests; D059027:Recycling; D022882:Trihalomethanes / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis; D018508:Water Purification / Q000379:methods*
chemical_list: D004202:Disinfectants; D060766:Drinking Water; D022882:Trihalomethanes; D014874:Water Pollutants, Chemical
keywords: Combined filter backwash water; Comet assay; Drinking water treatment; Genotoxicity; Micronucleus