title: Formation of nitrogenous disinfection by-products from pre-chloramination.
abstract: A sampling survey investigated the formation of nitrogenous disinfection by-products (N-DBPs) and carbonaceous DBPs (C-DBPs) from pre-chloramination, an increasingly common treatment strategy in China for regulated C-DBP control, followed by subsequent conventional water treatment processes, i.e., coagulation, sedimentation, and filtration. Dihalogenated N-DBPs typically peaked in the summer and early autumn with a relatively higher temperature, with the maximum levels of dichloroacetamide (DCAcAm), dichloroacetonitrile (DCAN), bromochloroacetonitrile, dibromoacetonitrile and dichloroacetone at 1.8, 6.3, 6.0, 2.6 and 1.8μgL(-1) in the finished water, respectively. Also, the levels of all the dichlorinated N-DBPs were correlated with the ratio of dissolved organic nitrogen (DON) to dissolved organic carbon, implying autochthonous DON played an essential role in the formation of these DBPs. In contrast, the yields of trihalogenated DBPs [chloroform (CF), trichloronitromethane (TCNM) and trichloroacetone (TCAce)] appeared not to be significantly affected by seasons. CF and DCAN were the dominant species in trihalomethanes (THMs) and dihaloacetonitriles (DHANs), respectively. Bromine was more readily incorporated into DHANs to form brominated DBPs than THMs during pre-chloramination. Although pre-chloramination can ensure the finished water to meet with the current Chinese THM regulatory limits, the increased levels of TCNM and TCAce may be a new water quality concern.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, China.
authors.forename: Wen-Hai
authors.initials: WH
authors.lastname: Chu
authors.forename: Nai-Yun
authors.initials: NY
authors.lastname: Gao
authors.forename: Yang
authors.initials: Y
authors.lastname: Deng
authors.forename: Michael R
authors.initials: MR
authors.lastname: Templeton
authors.forename: Da-Qiang
authors.initials: DQ
authors.lastname: Yin
mesh_terms: D000081:Acetamides / Q000032:analysis; D000097:Acetonitriles / Q000032:analysis; D002713:Chlorine / Q000737:chemistry*; D002725:Chloroform / Q000032:analysis; D004203:Disinfection; D060766:Drinking Water / Q000737:chemistry; D054879:Halogenation; D009584:Nitrogen / Q000737:chemistry*; D013696:Temperature; D022882:Trihalomethanes / Q000032:analysis; D018508:Water Purification
chemical_list: D000081:Acetamides; D000097:Acetonitriles; D060766:Drinking Water; D022882:Trihalomethanes; D002713:Chlorine; D002725:Chloroform; C121970:bromochloroacetonitrile; C032619:2,2-dichloroacetamide; D009584:Nitrogen; C051716:dichloroacetonitrile; C051715:dibromoacetonitrile