title: Effect of UV irradiation on the proportion of organic chloramines in total chlorine in subsequent chlorination.
abstract: This study investigated the changes of chlorine species and proportion of organic chloramines during the chlorination process after UV irradiation pretreatment in drinking water. It was found that the UV pretreatment could enhance the percentage of organic chloramines by increasing free chlorine consumption in the chlorination of raw waters. The percentage of organic chloramines in total chlorine increased with UV intensity and irradiation time in raw waters. However, for the humic acid synthesized water, the percentage of organic chloramines increased first and then decreased with the increase of UV irradiation time. The value of SUVA declined in both raw and humic acid synthesized waters over the UV irradiation time, which indicated that the decomposition of aromatic organic matter by UV could be a contributor to the increase of free chlorine consumption and organic chloramine proportion. The percentage of organic chloramines during chlorination of raw waters after 30-min UV irradiation pretreatment varied from 20.2% to 41.8%. Total chlorine decreased obviously with the increase of nitrate concentration, but the percentage of organic chloramines increased and was linearly correlated to nitrate concentration.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
authors.forename: Tian-Yang
authors.initials: TY
authors.lastname: Zhang
authors.affiliation: Department of Safety, Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, Kaohsiung 824, Taiwan, ROC.
authors.forename: Yi-Li
authors.initials: YL
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China. Electronic address: tjwenwu@tongji.edu.cn.
authors.forename: Bin
authors.initials: B
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
authors.forename: Sheng-Ji
authors.initials: SJ
authors.lastname: Xia
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
authors.forename: Fu-Xiang
authors.initials: FX
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
authors.forename: Nai-Yun
authors.initials: NY
authors.lastname: Gao
mesh_terms: D002700:Chloramines / Q000032:analysis* / Q000528:radiation effects; D002713:Chlorine / Q000032:analysis* / Q000528:radiation effects; D004203:Disinfection; D005618:Fresh Water / Q000737:chemistry*; D054879:Halogenation; D006812:Humic Substances / Q000032:analysis*; D009566:Nitrates / Q000737:chemistry; D014466:Ultraviolet Rays; D018508:Water Purification / Q000379:methods*
chemical_list: D002700:Chloramines; D006812:Humic Substances; D009566:Nitrates; D002713:Chlorine; C030816:chloramine
keywords: Chlorination; Humic acid; Organic chloramines; Raw water; Total chlorine; UV irradiation