Abstract
Inactivation of bacteria in water by the phtocatalytic oxidation and repression of the photoreactivation were studied. By counting bacteria with Standard Plate Count (SPC) method and heterotrophic bacteria in the river water, the inactivation and photoreactivation effects under the condition of 254nm-ultraviolet irradiation and that of the black light (maximum intensity: 352nm (300nm-440nm) ) irradiation was examined. The inactivation effect by 254nm-ultraviolet irradiation was particularly remarkable than the black light irradiation, while the oxidative degradation potential was almost equivalent. And it was proved that the photoreactivation of bacteria could be suppressed by using the photocatalyst with 254nm-ultraviolet irradiation. Generation of aldehydes was confirmed in the 254nm-ultraviolet irradiation with photocatalyst of tap water, river water, and groundwater, however, their amount were very limited in typical reaction time for inactivation.
