Electric current induced bacterial inactivation in seawater: effects of various operating conditions

Abstract

Conventional water disinfection processes suffer from several disadvantages including safety and handling issues and may result in the formation of undesirable and often harmful by-products. Novel disinfection methods, such as the application of low electric current, may present more practical, viable, and sustainable processes. The present study investigates the effects of applying a low-intensity (0.1–1.0 A) direct electric current for short durations (5–30 s) on the inactivation of different bacteria in seawater. The effects of distance between electrodes (5, 10, 15 cm), pH of seawater (6, 8, 10), and operating temperature (10, 20, 30 °C) on the inactivation process are examined. The sole effect of electric current on the inactivation of bacteria, as opposed to the combined effects of current and chlorine generated by seawater electrolysis, was a set study objective. The results show that inactivation of bacteria is achieved at different rates reaching values of 100%. The level of inactivation was found to be influenced by current intensities, application times, bacteria, and distances between electrodes. The results also show that pH and temperature, within the ranges investigated, have an insignificant impact on the inactivation process. Scanning electron microscope imagery revealed inactivation to be the result of bacterial cell wall damage.