Today’s Solutions: December 18, 2025

The unpredictable and extreme weather patterns we are experiencing due to the climate crisis are making it increasingly difficult, especially for big urban areas, to stay on top of storm drainage and wastewater management.

Heavy rainfall and flooding overwhelm stormwater management systems, especially in coastal areas, and this can lead to backups where runoff containing contaminants like garbage, sediment, and bacteria into local waterways, which lowers water quality overall and threatens our drinking water.

In Canada, six trillion liters of municipal wastewater gets released into the environment yearly, while another billion liters of untreated sewage is pushed into untouched waters when water treatment systems and facilities can’t take the intensity of passing storms, which leads to more water contamination.

Fortunately, a team of researchers from a collection of universities in Canada and the United Kingdom may have found a better and more beautiful solution to treating wastewater: willow trees.

The team studied a willow tree plantation in Quebec and discovered that the ethereal-looking trees were able to filter over 30 million liters of primary wastewater, which was administered to the trees through an irrigation system, per hectare over three years.

Eszter Sas, the lead author of the study and Ph.D. student at the Université de Montréal, says that they are “still learning how these trees can tolerate and treat such high volumes of wastewater, but willows’ complex ‘phyto’-chemical toolkit is giving us exciting clues.”

The researchers were astonished to find that there was no leaching of the wastewater and that all of it was captured and treated by the trees themselves.

This could mean that modern treatment facilities could be enhanced or even replaced by acres and acres of willow trees, which would have multiple benefits for the environment.

Frédéric Pitre, a senior author of the study and professor at the Université de Montréal says that an expansive willow water treatment facility could “[create] an environment for birds and insects… [increase] biodiversity and [cool] down the area—it [would make] green islands instead of heat islands.”

According to the United Nations, an estimated 80 percent of untreated wastewater generated from human activity is released into natural ecosystems, which then lead to a multitude of public health issues across the globe. The team behind the willow water treatment study hopes that their work piques other researchers’ interest and will lead to more findings of other plants that are well suited for treating wastewater across more climates.

Source Study: Science of the Total Environment—Biorefinery potential of sustainable municipal wastewater treatment using fast-growing willow

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