[Synergistic disinfection of Bacillus subtilis spores by UV irradiation and chlorine].

The inactivation effect of Bacillus subtilis spores was studied, both UV irradiation and chlorine disinfection individual and combined application process was examined with laboratory water samples. Results show that only 0.53 lg reduction was achieved by chlorine with CT value of 300 (mg x min)/L, UV irradiation is more effective than that of chlorination, at a UV dose of 40mJ/cm2 results in 3.3 lg reduction. Up to 6.2 lg reduction are achieved with a UV dose of 40mJ/cm2 following by chlorine with CT value of 300 (mg x min)/L. The calculation from the Berenbaum formula verified that the effect of the combined applications of UV irradiation and chlorine in inactivatiing Bacillus subtilis is a kind of synergistic effect.