Effect of ozone on the viability of some protozoa in drinking water

In this study, water samples from household tanks in several districts of Alexandria were examined for protozoa contamination and studying the effect of ozone and chlorine on their viability. The parasitic protozoa encountered were Giardia, Cryptosporidia, Blastocystis, Cyclospora and Microsporidia. Distilled water was treated by ozone or chlorine. Ozonated water samples were prepared at a concentration of 1 ppm after contact times with ozone of three, five, seven and nine minutes. Chlorine concentrations were 4 and 8 ppm. Parasites were incubated overnight at room temperature with the treated distilled water. The viability of the parasites was assessed by examining the intestinal sections of the infected animals