Traitement D’une Solution Colorée Et D’un Rejet Alimentaire Par Les Procédés D’électro- Fenton Et D’électro- photo-fenton

Abstract

This final-year project is part of the fight against industrial water pollution, particularly wastewater contaminated with dyes, whether of synthetic origin or derived from agro-industrial discharges. These substances are generally characterized by high chemical stability, low biodegradability, and significant toxicity to aquatic environments, making their removal by conventional processes difficult. In response to this issue, advanced oxidation processes, particularly electrochemical methods, offer a promising alternative. In this context, two complementary approaches were investigated. The Electro-Fenton process was applied to a synthetic solution containing the dye Bezactiv Yellow. A parametric study was conducted to assess the influence of certain operating parameters, namely the amount of catalyst, the electrolyte concentration, and the current density. The results revealed remarkable treatment efficiency: the chemical oxygen demand (COD) was reduced from 150 mg/L to 12 mg/L, corresponding to a 92% removal rate, while the total organic carbon (TOC) decreased from 50 mg/L to 2 mg/L, indicating a 96% mineralization of the initial organic matter after 45 minutes of treatment. In parallel, the Electro-Photo-Fenton process was implemented for the treatment of real wastewater from the juice production unit of the BIFA company in Constantine. In this case, an optimization approach based on a Box-Behnken design of experiments was used to identify the most effective operating conditions for maximizing COD reduction. The model identified optimal conditions corresponding to a catalyst concentration of 1.5 g/L, NaCl concentration of 4.76 g/L, and a current density of 11.97 mA/cm². These parameters led to a COD reduction rate estimated at 50.10 %, close to the set objective. The results obtained confirm the effectiveness of both processes in their respective contexts. The Electro-Fenton process proved particularly efficient for the advanced degradation of a synthetic dye in a controlled environment, while the Electro-Photo-Fenton process led to a significant improvement in the quality of real agro-industrial effluent. These processes appear to be robust, eco-friendly, and adaptable solutions capable of enhancing the treatment strategies for colored wastewater in both industrial and environmental sectors.