Removal of E.coli and S. aureus from aqueous solution by using electrocoagulation/ electroflotation process

Electrocoagulation is an electrochemical method for the treatment of water and waste water. Water disinfection by electrochemical methods has been increasingly carried out recently. The aim of this applied research is to investigate the removal of E. coli and S. aureus bacteria from drinking water by using Electrocoagulation (EC) - Electroflotation (EF) with Stainless Steel - Graphite felt electrodes parallel with the monopole mode.
An experimental study was conducted in a batch system. In this study, the contaminated water samples were prepared by adding104, 105 and 106 CFU/ml E. coli and S. aureus. Independent variables Including: different concentrations of E.coli and S. aureus bacteria (104, 105 and 106 CFU/ml), reaction time (5, 10, 15 and 20 min), initial pH (7, 8 and 9), electrode gap (1, 2 and 3 cm), current density (0.83, 1.67 and 3.3 mA/cm2) to determine the optimum conditions were investigated. One-way ANOVA was used to analyze the results.
The results show that in the optimum conditions with increasing the pH from 7 to 9 removal efficiency of bacterial strains of E.coli and S. aureus were decreased significantly from 100% to 80% and 100% to 83%, respectively. In initial concentration of 105 CFU/ml, optimum conditions were obtained for current density, reaction time and electrodes gap; 3.3 mA/cm2, 20 min and 2 cm, respectively.
According to the results, E.coli and S. aureus removal efficiency in optimum conditions was obtained, 100%. Thus, the EC/EF process can be used for removal of pathogenic bacteria from drinking water.