Journal of North Khorasan

Background & objectives: Presence of various microorganism, particularly human pathogens, in drinking water causes many health problems. Therefore, the water disinfection has been one of the main drinking water treatment processes. E. coli bacteria is known as an appropriate microbial water quality indicator. Electrochemical processes are very powerful for the removal of pollutants, particularly microbial contaminants, due to low environmental effects, ease of use and relative costs down for it. The aim of this study was to investigate the performance of electrochemical process in E. coli bacteria removal from water as well as the effect of various parameters on the performance of it.

Material & Methods: The electrochemical reactor was constructed and E. coli bacteria removal performance of under the influence of current density, initial bacteria population and supporting electrolyte type and concentration have evaluated.

Results:  The best performance of the electrochemical system was obtained in the current density of 6 mA/cm², concentrations of 0.25 g/l for each NaCl and Na₂SO₄ as supporting electrolyte and CFU/100 ml initial bacterial population.

Conclusion: With the increasing current density up to 6 mA/cm², efficiency of bacteria removal  was significantly increased. In investigation on effect of supporting electrolyte type and concentration were shown that by increasing the concentration of NaCl, the performance showed a significant increase E. coli removal. This performance has not been obtained in the case of Na₂SO₄ as supporting electrolyte.  With increasing of the initial bacteria number, higher time were needs to the complete elimination E.coli, when the initial bacterial number were increased.

Key words: Electrochemical techniques, Escherichia coli, Polluted water