Water is something we rarely think about until it’s gone or dirty. Wastewater treatment is one of the quiet challenges of modern life, and algae are surprisingly good at helping.

The process is called phycoremediation. Algae feed on nutrients that pollute water, such as nitrogen and phosphorus, which come from households, farms, and industries. As the algae grow, they absorb these nutrients. The water gets cleaner, and the algae thrive.

It’s nature’s version of a recycling system.

Unlike many conventional methods, algae-based treatment can use less energy and fewer chemicals. It can also produce biomass that is put to good use rather than thrown away.

It’s worth being clear that this isn’t the same as an algae tree. An algae tree is an air-purifying device, while wastewater treatment works with algae in water systems built for that job. Both draw on the same living organism, just in different ways.

Small ideas, treated with care, can solve big problems. This is one of them.