Ozone inactivation of Pseudomonas aeruginosa, Escherichia coli, Shigella sonnei, and Salmonella typhimurium in water

Based on the properties of ozone as a strong germicidal agent, inactivation kinetics of Pseudomonas aeruginosa, Escherichia coli, Shigella sonnei and Salmonella typhimurium towards ozone in water were studied. The values of 9 0% inactivation (t(90)) obtained varied from 0.20 minutes (2.4 mg/L, Escher ichia coli ATCC 25922) to 8.33 minutes (0.39 mg/L, Pseudomonas aeruginosa w ild strain). First order inactivation kinetics with respect to both the con centrations of ozone and microorganisms were found, resulting an overall se cond order inactivation kinetics. The ATCC strains showed to be the most se nsitive toward ozone among all. Meanwhile, the environmental isolation of P seudomonas aeruginosa was the most resistant and Escherichia coli the most sensitive wild strain. The longest time required to achieve total inactivat ion was 35 minutes.