This Natural Pool Cleans Itself With Plants, Not Chlorine

At a self-cleaning pool that just opened in London, you won’t find a toxic chemical in sight.

Most swimming pools are doused in chlorine as a disinfectant, despite the fact that the chemical can react with other things commonly found in pools—like pee and skin cells—to create byproducts linked to asthma and cancer. A new temporary pool in London takes a different approach by cleaning the water with plants instead.

In a “regeneration zone,” plants like pondweed and water lily absorb nitrates and ammonium and release oxygen, while microorganisms reduce algae and germs. Another section of the pool uses a gravel bed to host another layer of microorganisms for more cleaning. Throughout the day, pumps push the water from the swimming area through the filters.

The self-cleaning pool, which opened on April 1, was built as part of an art project on a site that’s slated for development. For the artists, it was a way to interact with a changing neighborhood—a new building will be constructed next to the pool as people swim—and also a way to literally immerse visitors in nature and help people think about the connection between their own health and the health of the environment.

“Visitors enter a living laboratory where they are aware of their relationship with nature, and about consequences of their interaction’s with nature and take responsibilities, they thus become actors,” say the designers, Slovenia-based artist Marjetica Potrc, and Dutch architects Eva Pfannes and Sylvain Hartenberg. “The water is important for the engagement of the actors. . . . They become aware of various natural processes by swimming in the pond.”

Read more: This Natural Pool Cleans Itself With Plants, Not Chlorine