The effects of pharmaceutical drugs reach far beyond our own bodies. Plenty of hormones and other chemicals found in medications end up in our pee and get flushed into the sewage system, contaminating water supplies and negatively affecting the ecosystem. There are trace amounts of antibiotics, hormones like estrogen—though mostly from sources other than hormonal birth control, like agricultural waste and soy products—and other pharmaceutical by-products that wastewater treatment plants don’t filter out. Over generations, these chemicals can affect the fertility of fish and frogs, among other environmental impacts.

One potential solution: a bacterial coating that would live in your toilet. As part of a student competition called the Biodesign Challenge, inventors Amanda Harrold, Kathleen McDermott, Jacob Steiner, and Perrine Papillaud of Rensselaer Polytechnic Institute in Troy, New York came up with the concept for Live(r) Clear, a living enzyme membrane designed to block pharmaceuticals from making their way into the sewage system, Popular Science reports.

Designed to act like “living wallpaper,” the toilet liner would coat the bowl “with enzymes capable of breaking down estrogen, so that less of it is sent to wastewater treatment plants,” co-creator Kathleen McDermott told mental_floss in an email. The idea is that the estrogen-eating microbes would live in a honeycomb structure made of something like silicone. It would adhere to the sides of the toilet bowl, trapping the hormones in the water before they end up down the pipes.

It’s just a speculative design for now, but the students are looking to incorporate enzymes similar to those used by the human liver, such as one called CP450.

The students are one group of many art and design students competing to show off their bio-inspired, futuristic projects at the Biodesign Summit in New York City in June.

[h/t Popular Science]

All images via the Biodesign Challenge unless otherwise noted.