Visible light plays a significant role during bacterial inactivation by the photo-fenton process, even at sub-critical light intensities.

The aim of this research is to clarify the contribution of sunlight wavelengths, irradiance and Fe/HO during bacterial disinfection by the photo-Fenton process in clear surface waters. We considered different solar spectrum distributions (visible, UVA-Visible), sub-critical irradiances (0-400 W/m), focusing on the action modes of E. coli inactivation by the constituents involved in the composite process, at low μM reactants concentration (Fe/HO) in in ultrapure (MQ) water.