Studies on the electrochemical disinfection of water containing Escherichia coli using a Dimensionally Stable Anode

Abstract

The aim of this work was to investigate the disinfectant effect of electrolysis on chlorine-free water, artificially contaminated with Escherichia coli (CCT-1457) and to evaluate the bactericidal activity of electrolysis and kinetic behavior of a single-cell reactor, with a DSA (Dimensionally Stable Anode) electrode to develop a scaled-up system. A high-density E. coli suspension (10(6) CFU mL-1) was electrolyzed in this reactor at 25, 50 and 75 mA cm-2 for up to 60 min, at flow rates of 200 and 500 L h-1. Bacterial survival fell by 98.9% without addition of chlorinated compounds and a power consumption rate not more than 5.60 kWh m-3 at flow rate of 200 L h-1 and 75 mA cm-2. The process produced a germicidal effect that reached this inactivation rate within a relatively short contact time. Also, a solution of electrolyzed 0.08 M Na2SO4 added to the inoculum showed residual bactericidal effect. The efficiency of disinfection was regulated by both the contact time and current density applied, and a kinetic function for the survival rate was developed for the purpose of scaling up.