A low-energy intensive electrochemical system for the eradication of Escherichia coli from ballast water: Process development, disinfection chemistry, and kinetics modeling

The invasion of biological organisms via ballast water has created threats to the environment and human health. In this study, a cost-effective electrochemical disinfection reactor was developed to inactivate Escherichia coli, one of the IMO-regulated indicator microbes, in simulated ballast water. The complete inactivation of E. coli could be achieved within a very short time (150, 120, or 60s) with an energy consumption as low as 0.0090, 0.0074 or 0.0035kWh/m ³ for ballast water containing E. coli at concentrations of 10 ⁸, 10 ⁷ and 10 ⁶CFU/100mL, respectively. Electrochemical chlorination was the major disinfection mechanism in chloride-abundant electrolytes, whereas oxidants such as ozone and free radicals contributed to 20% of the disinfection efficiency in chloride-free electrolytes. Moreover, a disinfection kinetics model was successfully developed to describe the inactivation of E. coli.