Inactivation of Cryptosporidium and Giardia in Drinking Water by Ozone

The paper used the fluorescence staining method to study the effect of O3 inactivating Cryptosporidium and Giardia in water. The results indicated that O3 had the stronger inactivating ability. When the dosages of O3 were above 3.0 mg /L and exposure time was 7 min, the extinct rate can be achieved 99.9%. The turbidity and concentration of organics were found to be statistically significant in artificial water. With the increasing of turbidity and temperature, the inactivating effect decreased. The inactivating ability of O3 was stronger under acidic conditions than in alkalic circumstance. When the concentration of the organic in the reaction system is high, competition between Cryptosporidium, Giardia and organics with O3 which reduced inactivation ratio might take place.