title: Characteristics of C-, N-DBPs formation from algal organic matter: role of molecular weight fractions and impacts of pre-ozonation.
abstract: Extracellular organic matter (EOM) and intracellular organic matter (IOM) of Microcystis aeruginosa have been reported to contribute to the formation of carbonaceous disinfection by-products (C-DBPs) and nitrogenous disinfection by-products (N-DBPs). Little is known about DBPs formation from different molecular weight (MW) fractions, especially for N-nitrosodimethylamine (NDMA). This study fractionated EOM and IOM into several MW fractions using a series of ultrafiltration membranes and is the first to report on the C-DBPs and N-DBPs formation from chlorination and chloramination of different MW fractions. Results showed that EOM and IOM were mainly distributed in low-MW (<1 KDa) and high-MW (>100 KDa) fractions. Additionally, the low-MW and high-MW fractions of EOM and IOM generally took an important part in forming C-DBPs and N-DBPs, either in chlorination or in chloramination. Furthermore, the effects of pre-ozonation on the formation of DBPs in subsequent chlorination and chloramination were also investigated. It was found that ozone shifted the high-MW fractions of EOM and IOM into lower MW fractions and increased the C-DBPs and N-DBPs yields to different degrees. As low-MW fractions are more difficult to remove than high-MW fractions by conventional treatment processes, therefore, activated carbon adsorption, nanofiltration (NF) and biological treatment processes can be ideal to remove the low-MW fractions and minimize the formation potential of C-DBPs and N-DBPs. Moreover, the use of ozone should be carefully considered in the treatment of algal-rich water.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
authors.forename: Shiqing
authors.initials: S
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
authors.forename: Shumin
authors.initials: S
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China; China Academy of Urban Planning & Design, Beijing 100037, China. Electronic address: yishengshao2011@163.com.
authors.forename: Yisheng
authors.initials: Y
authors.lastname: Shao
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
authors.forename: Naiyun
authors.initials: N
authors.lastname: Gao
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002700:Chloramines; D004203:Disinfection; D060766:Drinking Water; D005110:Extracellular Space / Q000737:chemistry; D054879:Halogenation; D042541:Intracellular Space / Q000737:chemistry; D046931:Microcystis / Q000737:chemistry*; D008970:Molecular Weight; D009584:Nitrogen / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry*; D010126:Ozone / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D018508:Water Purification
chemical_list: D002700:Chloramines; D060766:Drinking Water; D009930:Organic Chemicals; D014867:Water; D010126:Ozone; D002244:Carbon; D009584:Nitrogen
keywords: Disinfection byproducts; Extracellular organic matter; Intracellular organic matter; N-nitrosodimethlamine (NDMA); Pre-ozonation