title: The effect of chlorine and combined chlorine/UV treatment on coliphages in drinking water disinfection.
abstract: Chlorine disinfection is a globally used method to ensure the safety of drinking water. However, it has not always been successful against viruses and, therefore, it is important to find new methods to disinfect water. Seventeen different coliphages were isolated from the treated municipal wastewater. These coliphages and MS2 were treated with different dosages of chlorine in drinking water, and a combined chlorine/ultraviolet irradiation treatment for the chlorine-resistant coliphages. Chlorine disinfection with 0.3-0.5 mg/L total chlorine (free Cl-dosage 0.12-0.21 mg/L) for 10 min achieved 2.5-5.7 Log10-reductions for 11 sensitive coliphages. The six most resistant coliphages showed no reduction with these chlorine concentrations. MS2 was intermediate in chlorine resistance, and thus it is not a good indicator for viruses in chlorine disinfection. In the combined treatment total chlorine of 0.05-0.25 mg/L (free Cl-dosage 0.02-0.08 mg/L) and ultraviolet irradiation (14-22 mWs/cm(2)) were more effective than chlorine alone, and 3-5 Log10-reductions were achieved for the chlorine-resistant strains. The chlorination efficiency could be increased by higher dosages and longer contact times, but this could increase the formation of disinfection by-products. Therefore, the combination treatment is a recommended disinfection method.
authors.affiliation: Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 1627, FI 70211 Kuopio, Finland E-mail: alyaaz@uef.fi; Department of Biology, University of Baghdad, College of Sciences for Women, Baghdad, Iraq.
authors.forename: Alyaa M
authors.initials: AM
authors.lastname: Zyara
authors.affiliation: Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 1627, FI 70211 Kuopio, Finland E-mail: alyaaz@uef.fi.
authors.forename: Eila
authors.initials: E
authors.lastname: Torvinen
authors.affiliation: Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 1627, FI 70211 Kuopio, Finland E-mail: alyaaz@uef.fi.
authors.forename: Anna-Maria
authors.initials: AM
authors.lastname: Veijalainen
authors.affiliation: Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 1627, FI 70211 Kuopio, Finland E-mail: alyaaz@uef.fi.
authors.forename: Helvi
authors.initials: H
authors.lastname: Heinonen-Tanski
mesh_terms: D002713:Chlorine / Q000494:pharmacology*; D003090:Coliphages / Q000187:drug effects* / Q000302:isolation & purification; D004202:Disinfectants / Q000494:pharmacology*; D004203:Disinfection / Q000295:instrumentation / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D060766:Drinking Water / Q000821:virology; D014466:Ultraviolet Rays; D018508:Water Purification / Q000379:methods*
chemical_list: D004202:Disinfectants; D060766:Drinking Water; D002713:Chlorine