New use for stones left over from olive oil production

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Scientists at the University of Granada have discovered a new use for olive stones left over from olive oil pressing.

Germán Tenorio Rivas of Department of Chemical Engineering of the University of Granada has found an interesting use for the apparently useless olive stones: they can be used to eliminate heavy metal pollution – in this case chrome – by biosorption from wastewater from industries such as paint manufacture, tanneries or metalworking.

On of the key advantages of the technique is that it provides a use for an otherwise useless agricultural residue. As Rivas points out, “We don’t need to bring it from anywhere else, we already produce it here, and we produce a great amount. It is also clean and cheap.”

The process of biosorption of chrome by olive stones stems from their capacity to retain metallic ions in their surface. Tenorio believes biosorption could be used instead of more expensive clean-up technologies, such as precipitation. Unlike these processes, the use of olive stones does not leave a toxic sludge. The end products are clean water and the olive stones with the retained metal, which can then be reclaimed.