title: Impact of UV/H2O2 pre-oxidation on the formation of haloacetamides and other nitrogenous disinfection byproducts during chlorination.
abstract: Haloacetamides (HAcAms), an emerging class of nitrogen-based disinfection byproducts (N-DBPs) of health concern in drinking water, have been found in drinking waters at μg/L levels. However, there is a limited understanding about the formation, speciation, and control of halogenated HAcAms. Higher ultraviolet (UV) doses and UV advanced oxidation (UV/H2O2) processes (AOPs) are under consideration for the treatment of trace organic pollutants. The objective of this study was to examine the potential of pretreatment with UV irradiation, H2O2 oxidation, and a UV/H2O2 AOP for minimizing the formation of HAcAms, as well as other emerging N-DBPs, during postchlorination. We investigated changes in HAcAm formation and speciation attributed to UV, H2O2 or UV/H2O2 followed by the application of free chlorine to quench any excess hydrogen peroxide and to provide residual disinfection. The results showed that low-pressure UV irradiation alone (19.5-585 mJ/cm(2)) and H2O2 preoxidation alone (2-20 mg/L) did not significantly change total HAcAm formation during subsequent chlorination. However, H2O2 preoxidation alone resulted in diiodoacetamide formation in two iodide-containing waters and increased bromine utilization. Alternatively, UV/H2O2 preoxidation using UV (585 mJ/cm(2)) and H2O2 (10 mg/L) doses typically employed for trace contaminant removal controlled the formation of HAcAms and several other N-DBPs in drinking water.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University , Shanghai, 200092, China.
authors.forename: Wenhai
authors.initials: W
authors.lastname: Chu
authors.forename: Naiyun
authors.initials: N
authors.lastname: Gao
authors.forename: Daqiang
authors.initials: D
authors.lastname: Yin
authors.forename: Stuart W
authors.initials: SW
authors.lastname: Krasner
authors.forename: William A
authors.initials: WA
authors.lastname: Mitch
mesh_terms: D000081:Acetamides / Q000138:chemical synthesis*; D001965:Bromides / Q000737:chemistry; D001966:Bromine; D002713:Chlorine; D004203:Disinfection; D054879:Halogenation; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007454:Iodides / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry / Q000528:radiation effects; D010084:Oxidation-Reduction; D014466:Ultraviolet Rays; D014867:Water; D014874:Water Pollutants, Chemical / Q000138:chemical synthesis*; D018508:Water Purification / Q000379:methods*; D014881:Water Supply
chemical_list: D000081:Acetamides; D001965:Bromides; D007454:Iodides; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D014867:Water; D002713:Chlorine; D006861:Hydrogen Peroxide; D009584:Nitrogen; D001966:Bromine