Cleaning up on olive-oil production

Cleaning up on olive-oil production

LIFE Environment is contributing to cleaning up olive-oil production. The MINOS project resulted in innovative ingredients for the pharmaceutical, cosmetics and food industries.

The EU is the global leader in olive production with 70% of global output. Spain alone produces 36% of the world’s olive oil, and the sector is a major contributor to the economies of Greece, Italy and Portugal as well as being important to Cyprus, France and Slovenia. Nevertheless, the economic benefits come at a cost.

Much of the EU olive harvest is processed into olive oil. Both olive growing and oil production use considerable volumes of water while refining processes generate significant waste. The waste streams are highly hazardous to the environment and present a number of treatment challenges. LIFE projects have demonstrated that good environmental practice can save money and lead to new business opportunities with wastes converted into saleable commodities.

In total, 4.6 million tonnes of olive-mill wastewater are produced each year in the EU – some 80 to 83% water. Another 15 to 18% are organic compounds – mainly phenols, polyphenols and tannins – while the remainder is inorganic elements such as potassium salts and phosphates.

Recovering polyphenols

The MINOS LIFE project in Crete focused on the recovery of polyphenols from the process waste for the pharmaceutical, cosmetics and food industries. A pilot plant was constructed for the integrated treatment of olive-mill wastewater and for the recovery of the polyphenols. The wastewater was treated with absorbent resins and organic solvents before undergoing a heat treatment that delivers the polyphenols.

Clean water emerging from the treatment was suitable for disposal in water bodies, irrigation and reuse in the plant. Other end products include polyphenols and sludge that, after further filtration, is composted with the olive leaves that are rejected as solid waste.

The resulting organic substances have a high economic value as ingredients for use in the production of pharmaceuticals and cosmetics and as food additives. They are rich in natural anti-oxidants, which can prevent colon and breast cancer, and have antibacterial and antiviral properties. This makes recovery an attractive alternative to discharge.

The system was optimised at a pilot scale but, for full-scale viability, the mostly small olive-oil mills would probably need to co-operate to invest in the necessary specialised equipment and to employ the specialised scientific personnel required. In this way the wastewater produced by each olive-oil producer would be treated in a central unit with significantly lower capital and operational costs than possible with installations in each individual mill.

MINOS has a high demonstration value and can be easily transferred to other geographical areas where there are many small-scale olive oil producers.

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