The next time you nosh on some tapas, don’t throw away those olive pits: they could provide a greener way of cleaning up industrial effluents.

That’s the conclusion reached by Ángeles Martín Lara, a doctoral student in the department of chemical engineering at the University of Granada.

Lara found that the waste produced from olives during the oil extraction process can be used to eliminate heavy metals from sewage or waste waters. Olive pits, pomace Iskins, pulp and stems) and remains from olive tree pruning, it turns out, have an outstanding capacity to retain lead in effluents.

Lara and professors Francisco Hernáinz Bermúdez de Castro, Gabriel Blázquez García and Mónica Calero de Hoces conclude that “biosortion represents a viable alternative … , both for its depuration capacity and its economic operation cost; it has also been considered as a ‘clean’ technology in the elimination of heavy metals in sewage and waste waters of productive activities.”

The olive industry produces great amounts of such waste byproducts in Andalusia and their costs are very low or even null; sometimes, their management can become a problem. Their use as biosorbents of heavy metals, according to the researchers, “makes them a very desirable alternative, as they would have an extra value before their final elimination.”

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