Application of Supercritical CO2 Bubbling to Inactivate E. coli and Coliform Bacteria in Drinking Water

The effect of the continuous flow of supercritical CO2 microbubbles (the SC-CO2 method) on the inactivation of both Escherichia coli in model water and coliform bacteria in water prior to treatment at a municipal water filtering plant were studied as away to produce safe drinkable tap water. The number of surviving cells in both samples drastically decreased above a certain concentration of dissolved CO2 (gamma = 25). When treated for 13.3 min, cells were not detected at concentrations over gamma = 30. The dependences of the number of surviving cells on the concentration of dissolved CO2 were similar in both the treatments for 6.7 and 13.3 min. Therefore, it was suggested that effective inactivation could be achieved by minimizing the treatment time. From these results, it was proposed that the SC-CO2 method might be effective in inactivating E. coli and coliform bacteria for the production of public drinking water.