Wood waste from BC forestry sector may be key to removing microplastics from water
It’s a hidden pollution problem that’s also one of the most common on Earth.
Microplastics have been found in more than 99% of tap water samples in Canada, the US and Europe — along with every single water body from the Antarctic to the North Pole. And 10 billion tonnes of it will have accumulated in the environment by 2025.
But now a team from the University of British Columbia has unlocked what they believe is a silver bullet solution to removing it almost entirely, using worthless waste products from sawmills.
Scientists at UBC’s BioProducts Institute found that adding tannins — natural plant compounds that make your mouth pucker if you bite into unripe fruit — to a layer of wood dust, it can create a filter that traps virtually all microplastic particles present in water.
Those same tannins are found in wood dust and tree bark, materials that would typically be burned, to create a filter capable of removing 99.9% of microplastics from water. They call it the ‘bioCap’.
“Our filter, unlike plastic filters, does not contribute to further pollution as it uses renewable and biodegradable materials: tannic acids from plants, bark, wood and leaves, and wood sawdust—a forestry byproduct that is both widely available and renewable,” said Dr. Orlando Rojas, the institute’s scientific director.
Rojas, a professor in the Departments of Wood Science, Chemical and Biological Engineering, and Chemistry at UBC, adds it’s difficult to capture all the different kinds of microplastics in a solution, as they come in different sizes, shapes and electrical charges.
The plastics themselves are found in an enormous amount of everyday disposable items, including microfibres from clothing, microbeads from cleansers and soaps and foams and pellets from utensils, containers and packaging. Even in women’s makeup products and disposable masks.
“By taking advantage of the different molecular interactions around tannic acids, our bioCap solution was able to remove virtually all of these different microplastic types.”
While most technical solutions proposed to date are costly or difficult to scale up, the UBC’s solution could potentially be scaled down for home use or scaled up for municipal treatment systems.
“Our filter, unlike plastic filters, does not contribute to further pollution as it uses renewable and biodegradable materials: tannic acids from plants, bark, wood and leaves and wood sawdust—a forestry byproduct that is both widely available and renewable.”