Cleaning up dirty water has been on the agenda of many scientists lately. That’s no surprise—water pollution poses a health risk pretty much everywhere, especially in developing countries, where kids play among sewage, workers toil in muck daily, and millions die from drinking contaminated water every year. Scotland-based Biomatrix Water offers one more innovative way to clean up the mess: installing islands that suck up pollution from the water they're floating in.

The islands look and work like wetlands. Man-made structures hold together their vegetation; the pollutant-sucking process works naturally. Roots suspended beneath the islands promote the growth of aquatic biofilm (the green slime you find on rocks) that “cleanse[s] the water through the breakdown, sorption, and metabolic transformation of nutrients and impurities,” explains the Biomatrix website. Treatment plants have used biofilm filters for decades, reports Fast Company. But the company’s engineering additions, such as columns of synthetic fiber, maximize the growth of the beneficial bacteria that absorbs pollutants.

The islands come in different shapes and sizes and can be modified to grow local greenery. Besides increasing biofilm in the water, they also serve as fish refuges and feeding zones, creating low-maintenance ecosystems that could improve the area’s biodiversity while thriving for more than 20 years. The buoyant structures are also nice to look at: They can hold trees, driftwood, and even sculpture.

Partnering with conservationists and local governments, the company has already installed the pseudo-wetlands in the Philippines, India, China, and other countries.