Mitra Gholami , Shahram Nazari, Ahmad Reza Yari , Seyed Mohsen Mohseni , Soudabeh Alizadeh Matboo ,
Volume 75, Issue 2 (5-2017)
Background: Electrolysis is an electrochemical method for the treatment of water. recently water disinfection by electrochemical methods has been increasingly carried out. The aim of this applied research was to investigate the removal of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria from drinking water by using electrolysis method with Al-Fe electrodes parallel with the monopole mode.
Methods: An experimental study was conducted in the laboratory of microbiology, Iran University of Medical Science in May 2017. In this study, the contaminated water samples were prepared through adding 103, 104 and 105 E. coli and S. aureus bacteria per 1 milliliters (mL) of drinking water. Independent variables Included: different concentrations of E.coli and S. aureus bacteria (103, 104 and 105 CFU/ml), reaction time (5, 10, 15, 20 and 25 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.
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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 98 to 73% and 99.1 to 76%, respectively. In initial concentration of 104 CFU/ml, optimum conditions were obtained for current density, reaction time and electrodes gap, 1.67 mA/cm2, 20 min and 2 cm, respectively. With increasing current density and reaction time in both strains of bacteria, were decreased significantly. The electrodes gap do not have much impact on the efficiency of the process. The amount of electrical energy consumed in optimal conditions was calculated 0.5128 kilowatt-hour (kWh/h). Statistical analysis shows that exist significant relationship (P<0.01) between initial concentrations of bacterial strains and efficiency of the process.
Conclusion: According to the results, E. coli and S. aureus, removal efficiency were obtained more than 98%, therefore electrolysis process can be used in the removal of pathogenic bacteria from drinking water.
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