Inactivation of E-coli, B-subtilis spores, and MS2, T4, and T7 phage using UV/H2O2 advanced oxidation

The goal of this study was to evaluate the potential of an advanced oxidation process (AOP) for microbiocidal and virucidal inactivation. The viruses chosen for this study were bacteriophage MS2, T4, and T7. In addition, Bacillus subtilis spores and Escherichia coli were studied. By using H2O2 in the presence of filtered ultraviolet (UV) irradiation (UV/H2O2) to generate wavelengths above 295 run, the direct UV photolysis disinfection mechanism was minimized, while disinfection by H2O2 was also negligible. Virus T4 and E. coli in phosphate buffered saline (PBS) were sensitive to > 295 nm filtered UV irradiation (without H2O2), while MS2 was very resistant. Addition of H2O2 at 25 mg/l in the presence of filtered UV irradiation over a 15 min reaction time did not result in any additional disinfection of virus T4, while an additional one log inactivation for T7 and 2.5 logs for MS2 were obtained. With E. coli, only a slight additional effect was observed when H2O2 was added. B. subtilis spores did not show any inactivation at any of the conditions used in this study. The OH radical exposure (CT value) was calculated to present the relationship between the hydroxyl radical dose and microbial inactivation. (c) 2007 Elsevier B.V. All rights reserved.