Olive mill wastewater turned into biofuel and fertilizer

Researchers at the Institut de Science des Materiaux de Mulhouse created a new use for the billions of gallons of wastewater from olive oil production.

Mediterranean countries produce the majority of the world’s olive oil, an essential diet staple for millions of people. What is also produced along with the oil is billions of gallons of wastewater. Disposing of the waste has become a significant challenge for producers as the pollutant jeopardizes the health of groundwater, farmland and aquatic life. So far, approaches to disposal such as burning the wastewater have simply added additional pollution to the atmosphere.

Researchers from France’s Institut de Science des Materiaux de Mulhouse have found a solution that could improve the environmental footprint of olive oil production as well as provide additional benefits to farmers and local communities. By embedding the olive mill wastewater into another regional waste product, cypress sawdust, and rapidly drying and heating the mixture, the team of scientists produced water safe for irrigation use, a condensed gas bio-oil for use as a heat source and biofertilizer pellets.

With water being an incredibly precious resource, attempts to make more efficient use of it are being undertaken in nearly every industry. In parts of France, construction wastewater is being used for city irrigation and cooling systems, and another waste product (citrus peel) is being used to clean water while also gathering metals for re-use. How might notoriously resource-heavy production and supply chains such as the fashion industry make use of similar innovations?