Energetic Valorization of Wet Olive Mill Wastes through a Suitable Integrated Treatment: H2O2 with Lime and Anaerobic Digestion

In the Mediterranean region, the disposal of residues of olive oil industries representsan important environmental issue. In recent years, many techniques were proposed to improvethe characteristics of these wastes with the aim to use them for methane generation in anaerobicdigestion processes. Nevertheless, these techniques, in many cases, result costly as well as difficult toperform. In the present work, a simple and useful process that exploits H2O2 in conjunction withlime is developed to enhance the anaerobic biodegradability of wet olive mill wastes (WMOW).Several tests were performed to investigate the influence of lime amount and H2O2 addition modality.The treatment efficiency was positively affected by the increase of lime dosage and by the sequentialaddition of hydrogen peroxide. The developed process allows reaching phenols abatements upto 80% and volatile fatty acids productions up to 90% by using H2O2 and Ca(OH)2 amounts of0.05 gH2O2/gCOD and 35 g/L, respectively. The results of many batch anaerobic digestion tests,carried out by means of laboratory equipment, proved that the biogas production from fresh wetolive mill wastes is hardly achievable. On the contrary, organic matter abatements, around to 78%,and great methane yields, up to 0.34–0.35 LCH4/gCODremoved, were obtained on pretreated wastes