Solar photo-Fenton optimization for the treatment of MWTP effluents containing emerging contaminants

Growing use of xenobiotic substances, synthetic fragrances, pesticides, drugs, and other contaminants is leading to their increasing concentrations in the aquatic environment (over 1 μg/L). Conventional municipal wastewater treatment plants (MWTP) are unable to degrade these contaminants entirely. In this study, solar photo-Fenton process is proposed and optimized as a tertiary treatment for MWTP effluents containing emerging contaminants (ECs) and other micro-pollutants. A three-level factorial experimental design (33), modified with 2 × 3 axial and 6 central runs to make it spherical was carried out for optimization using Statgraphics software. The influence of hydrogen peroxide dosage, iron (II) concentration and temperature were assessed over accumulated energy (QUV kJ/L as the response factor) necessary to remove more than 95% of the micro-pollutants. Pareto graphic and response surfaces showed that Fe (II) concentration, temperature and their interaction are the variables that influence the response factor the most. Finally, the optimal operating conditions were successfully applied to the treatment of a real MWTP effluent at pilot plant scale removing 80% of total micropollutants after 0.56 kJ/L.