Disinfection of drinking water by using a novel electrochemical reactor employing carbon-cloth electrodes

A novel electrochemical reactor employing carbon-cloth electrodes was constructed for disinfection of drinking water. Escherichia coli K-12 (10² cells per cm³) was sterilized when a cell suspension was passed through the reactor at a dilution rate of 6.0 h^-1, and a potential of 0.7 V versus a saturated calomel electrode was applied to an electrode. The survival ratio increased with increasing dilution rate but was <0.1% at dilution rates of <6.0 h^-1. Although the survival ratio increased with increasing cell concentration above 10³ cells per cm³, the disinfection rate also increased. The disinfection rate was 6.0 x 10² cells per cm³ per h at a cell concentration of 10² cells per cm³. Continuous sterilization of E. coli cells was carried out for 24 h. Sterilization is based on an electrochemical reaction between the electrode and the cell which is mediated by intracellular coenzyme A. Sterilization of drinking water by using this reactor was successfully performed, demonstrating the potential of such a reactor for clean and efficient water purification.