Assessment of solar photo-Fenton, photocatalysis, and H2O2 for removal of phytopathogen fungi spores in synthetic and real effluents of urban wastewater

Abstract

Scarcity of fresh water is a major environmental problem, and properly treated wastewater could be an alternative renewable water resource, especially for agriculture as the final point-of-use. But before wastewater can be reused, it must be treated to meet chemical and biological quality standards, which depend on the final use and legislation. Advanced Oxidation Processes (AOPs) have been demonstrated to be very efficient in decreasing the pathogen load in contaminated water. This study presents the experimental evaluation of several solar-driven AOPs, i.e., photo-Fenton (Fe2+, Fe3+) at low reagent concentration, heterogeneous photocatalysis (TiO2), and solar photoassisted H2O2 treatment for removal of the spores of Fusarium sp., a worldwide phytopathogen. The experimental work was done in a pilot solar photoreactor with Compound Parabolic Collector (CPC). Disinfection of Fusarium solani spores by all treatments was excellent in distilled water, in simulated municipal wastewater effluent (SMWWE), and in real municipal wastewater effluents (RMWWE). Degradation of dissolved organic carbon (DOC) was also evaluated. The inactivation rates varied depending on the water matrix, and disinfection was fastest in distilled water followed by SMWWE, and RMWWE. The best F. solani inactivation rate was with photo- Fenton treatment (10/20 mg/L of Fe2+/H2O2) at pH 3, followed by H2O2/Solar (10 mg/L) and finally TiO2/Solar was the slowest. These results underline the importance of solar AOPs and the CPC reactor technology as a good option for waterborne pathogen removal.