Electrochemical disinfection of bacterial contamination: Effectiveness and modeling study of E. coli inactivation by electro-Fenton, electro-peroxi-coagulation and electrocoagulation

Abstract

The present work undertakes an examination and comparison of electro-Fenton (EF), electro-peroxi-coagulation (EPC) and electrocoagulation (EC) applied to the E. coli inactivation in batch reactor. Indeed, platinum (Pt (anode), EF), stainless steel (SS (cathode), EF, EPC) and ordinary steel (Fe (anode), EPC) and aluminum (Al, EC) were used respectively. The current intensity, nature of electrolytic support, bacterial density and hydrogen peroxide (H2O2) concentration are the most influenced study parameters. The obtained results showed that the high current intensities were significant for better inactivation and destruction of E. coli cells and caused a maximum of energy consumption. Both disinfection and energy consumption were improved by adding NaCl (or Na2SO4) in the three processes. Higher cellular density limited the electrochemical process and has negative effect in E. coli inactivation and the energy consumption. Only in the EPC case, the disinfection was considerably increased in function with H2O2 concentration. The modeling parameters of the inactivation kinetics of E. coli showed a good fitting of the established model (0.9560 < R2 < 0.9979, 0.9267 < R2 adjusted <0.997 and 0.0189 < RMSE <0.4821), faster kinetics of E. coli inactivation (significant values of Kmax and Sl) in the case of high current intensity (0.2442<Kmax<0.7440 and 10.50 < Sl < 24.69), the presence of chlorides or sulfates (0.6662<Kmax<0.7818 and 11.67 < Sl < 18.59), and the sufficient H2O2 concentration (0.4712<Kmax<0.9204 and 13.00 < Sl < 16.38). Moreover, the analysis of the results revealed that the EF is more effective in terms of the E. coli inactivation and the energy consumption comparatively to the other studied processes.