title: UV/H(2)O(2) treatment of drinking water increases post-chlorination DBP formation.
abstract: Ultraviolet (UV) irradiation has become popular as a primary disinfectant because it is very effective against Cryptosporidium and does not directly form regulated disinfection by-products. Higher UV doses and UV advanced oxidation (UV/H2O2) processes are under consideration for the treatment of trace organic pollutants (e.g. pharmaceuticals, personal care products). Despite the disinfection effectiveness of UV light, a secondary disinfectant capable of maintaining a distribution system residual is required to meet current U.S. regulation. This study investigated changes in disinfection by-product (DBP) formation attributed to UV or UV/H2O2 followed by application of free chlorine to quench hydrogen peroxide and provide residual disinfectant. At a UV dose of 1000 mJ/cm(2), trihalomethane (THM) yield increased by up to 4 microg/mg-C and 13 microg/mg-C when treated with low and medium pressure UV, respectively. With the addition of hydrogen peroxide, THM yield increased by up to 25 microg/mg-C (5mg-H2O2/L) and 37 microg/mg-C (10 mg-H2O2/L). Although no changes in DBPs are expected during UV disinfection, application of UV advanced oxidation followed by chlorine addition was assessed with regard to impacts on DBP formation.
authors.affiliation: Civil, Environmental and Architectural Engineering, University of Colorado at Boulder, 428 UCB, ECOT 441, Boulder, CO 80309-0428, USA.
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Dotson
authors.forename: Volha Olya S
authors.initials: VO
authors.lastname: Keen
authors.forename: Debbie
authors.initials: D
authors.lastname: Metz
authors.forename: Karl G
authors.initials: KG
authors.lastname: Linden
mesh_terms: D001966:Bromine / Q000032:analysis; D002713:Chlorine / Q000032:analysis; D004203:Disinfection; D054879:Halogenation; D006861:Hydrogen Peroxide / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry; D009930:Organic Chemicals / Q000032:analysis; D011312:Pressure; D012995:Solubility; D014466:Ultraviolet Rays; D018508:Water Purification / Q000379:methods*; D014881:Water Supply / Q000032:analysis*
chemical_list: D009930:Organic Chemicals; D017665:Hydroxyl Radical; D002713:Chlorine; D006861:Hydrogen Peroxide; D001966:Bromine