Energy Valorization of Olive Mill Waste Cake – Extraction of Vegetable Oil and Transesterification

Abstract

The olive mill wastewater, effluents from the trituration of olives, are treated in most Mediterranean countries by natural evaporation. However, this method of treatment is a source of air and soil pollution by the generation of solid waste, called olive mill waste cake. This work focused on extracting of vegetable oil from this by-product for biodiesel production by transesterification. The extraction took place with a Soxhlet extractor, using hexane as solvent. The vegetable oil and biodiesel were characterized by measuring the physicochemical parameters that identify them according to AFNOR standards. The extraction results show that the oil yield is 21.28%. The oil obtained is characterized by density, water and ash content, acidity, saponification, peroxide and ester. The yield of the oil esterification reaction is 86.41% or about 185 Kg of biodiesel/ton of olive mill waste cake, and in terms of energy 2783.7 MJ or 2 GW.t -1 . The biodiesel produced is comparable to petroleum diesel according to EN 14214, 2013.