Effective Inactivation of Bacillus subtilis Spores by a Combination Treatment of Ozone and UV Irradiation in the Presence of Organic Compounds

Abstract

The kinetics of the inactivation of Bacillus subtilis spores by ozone alone and ozone with UV irradiation were investigated in a circulation system of a 5.3l ofsaline suspension (10⁶ spores/ml) under various conditions of ozone concentration (3.0 and 7.0 mg/l in inlet gas) and UV intensity (3, 413 and 13, 650 μw/cm²).The spore inactivation by ozone with UV irradiation was more effective than by ozone alone in the presence of organic compounds such as tryptophan and ribose. The combination treatment of ozone and UV is considered to be a useful disinfection method for practical use.