A catalytic oxidation process of olive oil mill wastewaters using hydrogen peroxide and copper

The Mediterranean region is the largest olive oil producer in the world, consequently in this areaolive oil mill wastewaters have a high seasonal pollution potential. Due to the presence of phytotoxiccompounds, such as poly-phenols, the olive oil mill wastewater is not easily biodegradable,and, therefore, the direct biological treatment is not recommended. Many techniques have beenproposed for the their treatment, such as catalytic wet oxidation, ozonization, photo-catalysis,etc., among which, the catalytic oxidation seems to give good results. The present paper reportsthe results of an experimental investigation carried out with the aim to defi ne a new catalyticoxidation process with hydrogen peroxide using copper-based catalyst, able to reduce the phytotoxicityof olive oil mill wastewaters and to recover the catalyst after oxidation treatment. Theexperimental results have showed that, operating in a slurry type reactor at mild operating conditions,it is possible to reduce the organic chemical oxygen demand down to 10% and the polyphenolsamount of wastewater down to 1%. Therefore, the process is able to increase the rapidlybiodegradable substrate content up to 80%, to remove color and total suspend solid amount andto minimize the metal loss of the catalyst after oxidation process, with a recover of about 80%with respect to its initial amount, permitting to reuse it for a long life cycle.