Modeling and optimization of olive mill wastewater dephenolization by a process combining coagulation and advanced oxidation using an activated lime coagulant and hydrogen peroxide

Olive mill wastewater (OMW) is a non-biodegradable and toxic effluent that arouses the interest of the scientific community and stockholders owing to its imminent threat to the environment and health. The fluctuating character and the high rate of phenolic compounds complicate the decontamination process of these kinds of effluents. Hence, there is a need for innovative and effective treatments to neutralize these harmful impacts.

The present work aims at the treatment of polyphenolic compounds of OMW through the combination of the coagulation process with an activated lime coagulant and advanced oxidation using hydrogen peroxide (H₂O₂), and the elucidation of the effect of influencing factors to optimize OMW treatment performances. To this end, the optimization was achieved following an experimental design methodology, and the obtained results were very remarkable when compared to similar studies. By operating under the optimal conditions of 12.45, 26.5 mL.L⁻¹, and 2.5 min for pH, hydrogen peroxide (H₂O₂) ratio, and reaction time, respectively, removal efficiencies reached 98 % for polyphenols, 96.2 % for chemical oxygen demand (COD), 98.5 % for turbidity, and 94 % for color, with a low generated sludge volume of 37 mL/100 mL of OMW.