Olive Mill Wastewater: Treatment and Valorization

Abstract

AbstractFor more than 7000 years, olive oil production and consumption have been an established tradition in the Mediterranean area. Due to its great dietary and nutritional value, the olive oil industry is quickly growing across the world. Its manufacturing takes place in two ways: press extraction (the traditional method) and the continuous three-phase decanter process. Olive oil is extracted from the fruit of the olive and mixed with water to create a paste. Water is used in some of these steps to squeeze out most of the oil from the olive. The resulting paste is then mixed to increase the percentage of available oil. Both methods produce approximately (20%) olive oil, (30%) solid waste (olive husk) and 50% olive mill wastewater. This olive mill wastewater has a low pH and contains high toxic organic loads, which makes it a major environmental issue for countries producing olive oil. This chapter discusses the various approaches used for the mitigation of wastewater contaminants produced by the olive oil industry. Recent research studies which focused on the valorization options for dealing with olive mill waste residues such as animal feed, biofuel and biogas are also discussed.KeywordsOlive oilOlive oil extractionOlive mill wastewaterMediterranean areasWastewater treatmentValorization