Separation and purification of high purity products from three different olive mill wastewater samples

Morocco is known for producing olive oil, which release olive mill wastewater (OMW) on rates that are growing exponentially. This resulting effluent produced through discontinuous (traditional units) or continuous processes (modern and semi-modern units) is qualified as a highly polluting substance, since it contains great concentrations of chemical and biological oxygen demand and contains high concentration of organic substances. Despite its treatment throughout the extraction process, this liquid waste still contains a very important oily residue, always considered as a pollutant waste.This research is one of the first studies describing a new method to treat and value the OMW as well as to extract new eventual products. The proposed pre-treatment process consisted in a centrifugation in which the remaining oil from three OMW samples (press, two and three-phase centrifugation system) was recovered, the inclusion with urea came out with oleic and linoleic acid with high purities, the triglycerides forming this oily part were transformed into methyl esters, and then crystallized four times with urea at (4 °C and 20 °C) for methyl oleate and (−5 °C) for methyl linoleate, also biodegradable soap and extra pure glycerol were obtained with high qualities from the same phase. Furthermore, the aqueous phase resulting from centrifugation has been treated with ethyl acetate to recover the polyphenolic compounds with a yield of 67%.With this new procedure followed in the present study, from one liter of OMW's oil it seems possible to obtain 137 g of purified oleic acid and 37 g linoleic acid.In order to ensure both, feasibility and economic viability of the OMW treatment project, a case study was performed based on Marrakesh region data. The prototype of the unit yield favorable results.