5 startups that are reimagining the world

Tethis, which is Greek for "goddess of fresh water," is on a mission to make industrial wastewater reusable.

The startup has developed a foam-like biodegradable material that binds with pollutants, making it easier to soak them up and remove them from water.

Typically, industrial wastewater contains radioactive material, arsenic, salt and minerals. It's common to dump it into defunct wells, said co-founder Scott Bolin.

"This isn't a sustainable method," he said. "We want to not only clean the water at half the cost of traditional methods, but also make it reusable."

Bolin co-founded Tethis in September 2012 with two other partners, and has raised nearly $2 million in funding.

The firm is in the process of signing on its first industrial clients. "We're starting slowly. Once we've scaled up, we'd also be open to working with cities to clean up their water bodies," he said.