title: Combined ozone and ultraviolet inactivation of Escherichia coli.
abstract: The kinetics of Escherichia coli inactivation using ozone and ultraviolet (UV) radiation, separately and simultaneously, was evaluated at 25 degrees C in buffered (pH 6.0, 7.0 and 8.0), demand-free media. While ozone was found to be a stronger disinfectant than UV radiation, using both simultaneously was more effective than using them individually. Inactivation kinetics was pseudo first-order for the three treatment processes, while the disinfection rate was a linear function of the disinfectant dose. The synergism observed in microbial inactivation when the disinfectant processes were combined was illustrated by estimates of kinetic model parameters. This synergy was attributed to the generation of hydroxyl radicals via ozone photolysis. Subsequently, dosage calculations, as based on disinfectant level and exposure time, indicated that the simultaneous use of UV and ozone could substantially reduce their individual doses.
authors.affiliation: Department of Civil Engineering, Mississippi State University, Mississippi, 36762-9546, USA. magbanua@engr.msstate.edu
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Magbanua
authors.forename: Gaurav
authors.initials: G
authors.lastname: Savant
authors.forename: Dennis D
authors.initials: DD
authors.lastname: Truax
mesh_terms: D015169:Colony Count, Microbial; D004202:Disinfectants / Q000494:pharmacology*; D004203:Disinfection / Q000379:methods; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification / Q000528:radiation effects*; D007700:Kinetics; D010126:Ozone / Q000494:pharmacology*; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid; D014873:Water Pollutants / Q000302:isolation & purification / Q000528:radiation effects; D018508:Water Purification / Q000379:methods; D014881:Water Supply
chemical_list: D004202:Disinfectants; D014873:Water Pollutants; D010126:Ozone