Effect of ozone treatment on three bacterial strains of drinking water

Abstract

Because of its excellent disinfection and oxidation qualities, ozone is widely used for drinking water treatment. Ozone is frequently used to destroy and inhibit the growth of microorganisms from contaminated water. In this paper, ozone efficiency was tested for water treatment containing cell suspensions of Escherichia coli K12-MG 1655, Enterococcus faecalis ATCC 29212 and Pseudomonas aeruginosa ATCC 9027 using an ozone generator OZONFIX 8G. Water samples were subjected to ozone treatment for different periods, ranging from 15 seconds to 15 minutes. Ozone was generated by the corona discharge method. The use of electrical power to generate ozone by corona discharge is the most commercially viable method. Analyses were performed both for determining the cell viability by the total plate count technique, and for determination of the cell growth curves after the applied ozone treatment. The bacteria were cultured in liquid media on an orbital shaker at 150 rpm and 37° C. The bacterial multiplication was measured by recording the absorbance A600nm on a UV-VIS spectrophotometer. Following the experiments, it was found that ozone showed a strong effect of inhibiting the growth of the three bacterial strains, both in terms of viability and multiplication capacity. The most resistant was the bacterial strain of Pseudomonas aeruginosa ATCC 9027.