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Baltimore’s trash-eating waterwheel

A new twist on an old idea helped clean up a harbor

by Alexander H. Tullo
April 16, 2018 | A version of this story appeared in Volume 96, Issue 16

A photo of a waterwheel in Baltimore.
Credit: Craig Bettenhausen/C&EN
Mr. Trash Wheel has become a Baltimore icon.

John Kellett spent two decades on Baltimore’s Inner Harbor, first as an educator aboard boats that took schoolchildren to learn about the waterfront and then as director of Baltimore’s Maritime Museum.


Baltimore’s trash-eating waterwheel

“It was pretty obvious that trash was one of the major issues that Baltimore harbor faced,” he says. “Visitors to the harbor were remarking about it.”

It was also clear to Kellett that too much trash was bobbing around for it to come only from boats or visitors on foot. Local streams were gathering trash from around the region and carrying it into the harbor.

Then he seized on an idea: why not intercept the trash at those tributaries?

Kellett started with the Jones Falls, one of the major streams emptying into the bay. He also had a design. Floating booms would stop the flow of garbage, largely plastic flotsam, and funnel it to a machine. A waterwheel would drive a series of revolving rakes that would fish the trash out of the water and onto a conveyor that led to a dumpster on a barge.

The idea won support from Baltimore’s Abell Foundation, which financed a small prototype that Kellett installed in 2008. The pilot was so successful that the Waterfront Partnership of Baltimore footed the $700,000 needed to build a full-size machine.

Credit: Adam Lindquist
Baltimore’s Mr. Trash Wheel hard at work.

The machine, Mr. Trash Wheel, opened in 2014. Since then, Kellett estimates, it has collected more than 700 metric tons of trash. Volume is heaviest after a hard rain, which washes cigarette butts, plastic bags, polystyrene foam containers, and other junk down Baltimore’s gutters. After one storm, Kellett says, operators emptied the dumpsters 15 times, for a total of 50 metric tons. Mr. Trash Wheel costs about $100,000 per year to run.

The water is noticeably cleaner because of Mr. Trash Wheel, Kellett claims. “Everybody who uses the harbor or works around the harbor or walks around the harbor would say that it makes a tremendous difference,” he says.

Clearwater Mills, the company Kellett founded, is now building its third waterwheel in the area. It’s also looking to expand beyond Maryland. Clearwater Mills waterwheels may go up in Milwaukee; Honolulu; Newport Beach, Calif.; and Toronto. The firm is also evaluating two locations—the Bronx River and the Gowanus Canal—in New York City.

To Kellett, the satisfaction comes from both cleaner water and public awareness. “It helps people understand that pollution doesn’t start here in the harbor,” he says. “It starts in your neighborhood.”


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