Transforming Coffee Waste into an Agricultural Clean-Up Hero

A study has presented a novel approach to tackle agricultural contamination using an everyday waste product: used coffee grounds. Annually, around six million tonnes of coffee grounds are discarded, contributing to landfill overflow and the release of harmful greenhouse gases. However, this so-called waste might just be the answer to one of agriculture’s most pressing issues.

Researchers from Brazil’s Federal Technological University of Paraná have uncovered a method whereby used coffee grounds, when activated with zinc chloride, can become a potent absorber of bentazone. Bentazone is a herbicide widely used in agriculture that poses significant risks to water quality and, by extension, to human and environmental health. The study, published in the Journal of Chemical Technology and Biotechnology, demonstrated that coffee grounds treated to increase their carbon content could remove the herbicide more effectively by 70 percent.

This discovery not only has the potential to mitigate the harmful impacts of bentazone in surface water but also repurposes an abundant waste product, aligning with circular economy principles. The European Environment Agency has already flagged the presence of dangerous levels of bentazone in surface waters, threatening the EU’s environmental targets and necessitating more rigorous water treatment processes.