Enhancement of solar water disinfection using H2O2 generated in situ by electrochemical reduction

In this study, the solar water disinfection (SODIS) process was enhanced by in situ generated H2O2, and the influences of current, temperature, bacterial load, humic acid (HA), and bicarbonate were investigated. The results revealed that 1.29 kJ/L of electricity consumption reduced the treatment time by 40 % and decreased the required solar energy from 235.95-141.58 kJ/L. O-1(2) was the main reactive oxygen species (ROS), which played an important role. Increasing the current from 15 to 25 mA improved the cumulative H2O2 production, but it had no effect on the disinfection rate. Bicarbonate markedly suppressed E. coli inactivation. Decreasing the initial E. coli concentration reduced the required treatment time from 180 to 120 min. Increasing the temperature had a positive effect on the disinfection. HA concentration of 1 mg/L was the best for E. coli inactivation. In the presence of higher HA concentrations, it required a longer treatment time.