Comparative experimental evaluation and empirical modeling of advanced oxidation processes for organic compounds removal from cosmetic wastewater with statistical assessment

Cosmetic industry wastewater is characterized by high COD, recalcitrant organic compounds, and poor biodegradability, posing significant challenges to conventional biological treatment systems. This study addresses these challenges through a comprehensive evaluation of four advanced oxidation processes (AOPs): UV, UV/H₂O₂, Photo Fenton, and Photo Fenton like, aiming to identify a sustainable and scalable solution for treating real industrial wastewater collected from a cosmetics factory in Badr City, Egypt. Batch experiments were conducted under varied conditions of pH, hydrogen peroxide dosage, catalyst concentration (Fe⁺² or Fe⁺³), and UV irradiation time. Among the tested processes, the Photo-Fenton system showed the highest performance, achieving 95.5% COD removal and enhancing the biodegradability index (BOD₅/COD) from 0.28 to 0.8 under optimized conditions (pH 3, 0.75 g/L Fe⁺², 1 mL/L H₂O₂, 40 min). Kinetic modeling was applied to all tested AOPs, and the results indicated that pseudo-first-order kinetics best described the degradation behavior, confirming the role of hydroxyl radicals in organic removal. A multiple linear regression model (R² = 0.851) was also developed to predict COD removal efficiency based on process parameters and statistical analysis confirmed significance of the optimal conditions. Energy and cost evaluations identified the Photo-Fenton process as the most efficient and economically feasible option, with the lowest specific energy consumption and material costs per liter treated. These findings suggest that the Photo Fenton process is a viable pre-treatment option for cosmetics wastewater, particularly in decentralized or industrial treatment systems. Future work should focus on scaling the process and integrating it with biological treatment units to improve sustainability.