shows a CPC disinfection experiment upscaled to 14 L of distilled water. The addition of 50 mg/L H2O2 reduced the Fusarium CFUs by 2.6 logs. The blank experiment without H2O2 reduced the fungal spores 0.8 log with the same average irradiance of 23 W/m2. The H2O2 concentration decreased 18.1 mg/L almost linearly during the experiment from 49.8 mg/L (starting concentration) to 31.7 mg/L (final concentration). In the dark experiments, the H2O2 concentration only decreased slightly (2.5 mg/L). The temperature reached from 25 to 33 °C during solar exposure. The reaction H2O2 consumption profile is linear to the “normalized illumination time” similar to photo-Fenton-like decomposition of H2O2 in degradation of chemical compounds in CPC reactors ( Malato et al., 2002 and Pérez-Estrada et al., 2005). Slight H2O2 losses (0.1 log) in the dark can be attributed to enzymatic decomposition by the fungal spores ( Sousa-Lopes et al., 2004).