A new olive oil production scheme with almost zero wastes

Abstract

Disposal and/or treatment of olive mill wastewaters (OMW) or semisolid wastes (alperujo) are among the most important environmental problems in the Mediterranean region due to the presence of high organic content, e.g., phenols, low nitrogen concentration, and high concentrations of slowly biodegradable compounds such as lipids and fatty acids. In the present study, a new scheme for olive oil production process with almost zero wastes is proposed where all the olive fruit ingredients are used for the production of goods: extra virgin olive oil, olive pomace oil, various antioxidants, animal feed, solid fuels, and water for irrigation. The idea involves separation of the, rich in oil, pulp (60–65%) from the olive pit (stone). The pit contains a woody shell and the kernel (seed) which also contains oil and can be utilized for the extraction of olive-residue oil with hexane while the remaining solid is used as biofuels (pellet). First, the paste is driven to a pilot oil extraction system (2-phase decanter) to get the olive oil and then the phenols are extracted from the remaining pulp. The remaining paste (solid edible phase) can be sterilized using UV and can be enriched with spices and herbs to produce edible solid paste for food industry or for animal food. The extracted samples of phenolic and other miscible organic substances are treated with a membrane system for the enrichment of phenolics. The commercialization of phenols and other isolated byproducts can contribute to reducing the cost of the proposed process.