Check out this piece from IowaWatch.org on Lou Licht and his earth-cleaning poplars.

NORTH LIBERTY – Lou Licht was once a polluter – aiding and abetting companies that spewed toxins into the air and water.

Today he could hardly be greener.

With a quick-growing, toxic-zapping tree and a patented technique, Licht cleans up the types of messes he once helped create. His professional and environmental interests are wrapped up in trees, and he hopes to apply his work in Iowa.

He’s an entrepreneur with a doctorate in civil and environmental engineering from the University of Iowa. But in some ways, Licht still is like the dairy farmer he grew up as. Only now, he grows things. His crops are poplar trees that filter fine particles and formaldehyde from the air. When planted in swales, they retain and filter water from rain, reducing storm surges and runoff in flood-prone states like Iowa. And, they can treat sewage.

“In the case of Iowa, where we are surrounded by farmland, the right 15-20 acres can do all the tertiary treatment for a town of 1,000 people,” he said.