Application of the sono-Fenton/UV process on the treatment of table olive processing wastewater

Abstract The Mediterranean Basin economies of Spain, Italy, Greece, and Turkey depend on the table olive and olive oil industries. Table olive processing wastewater characteristics and quantity depend on olive varietal and processing methods. Olives and processing methods provide phenol, suspended particles, dissolved inorganic solids, and refractory organics. Due of its complexity, conventional methods struggle to tackle table olive processing wastewater. A novel approach to enhanced oxidation processes integrates many ways to boost hydroxyl radical formation and scale up efficiency. UV assisted sono-Fenton process as a modified Fenton process was applied to table olive washing wastewater to achieve high formation of hydroxyl radicals. When UV assisted sono-Fenton experiments executed to determine the optimum reaction conditions, the effects of hydrogen peroxide, ferrous ion concentrations and reaction time on the oxidation of table olive washing wastewater investigated by using a statistical experimental design. Chemical oxygen demand (COD), total organic carbon (TOC) and phenol removal efficiencies were examined by keeping the pH constant. The UV assisted sono-Fenton process achieved 53% phenol, 68% TOC, and 80% COD removal efficiencies. The results show that the UV assisted sono-Fenton process can treat effectively table olive processing wastewater. Optimum reaction conditions for the UV assisted sono-Fenton process were determined. UV assisted sono-Fenton process provides a significant reduction in reaction time and minimizes the costs of process associated with low chemical requirements. So, these optimum reaction conditions were resulted in low sludge production at the UV assisted sono-Fenton process while treating table olive processing wastewater.