Originally created 02/08/02

Scientists find steel pollutant-eating bacteria



People started calling Christine Schuster names when they heard she was spreading bacteria around the west side of U.S. Steel's Gary (Ind.) Works, North America's largest steel complex.

"I was known as the bug lady around here for a short period of time," said Schuster, whose job is making sure Gary's west side complies with environmental regulations.

There are bad bugs and there are good bugs. With the help of Carnegie Mellon University scientists, Schuster deployed some good bugs to attack a problem with an intimidating name: Carbonaceous Biological Oxygen Demand, or CBOD.

Because of CBOD, carbon compounds in the 30 million gallons of water Gary's west side discharges daily were consuming oxygen in the waters of the Grand Calumet River, which flows into Lake Michigan. The lack of oxygen threatened fish, which breathe oxygen through their gills. CBOD wasn't a problem until the river water was heated by the summer sun, depriving it of even more oxygen.

In 1998, the Gary Works violated Indiana Department of Environmental Management regulations governing CBOD six times during the months of July, August and September. The violations prompted state officials to order U.S. Steel to take care of the problem.

It took as much as $1 million in research, but working with U.S. Steel employees, an outside contractor and CMU scientists, Schuster came up with a much less expensive solution: germs.

"Bacteria work cheap, but they're slow," said Edwin G. Minkley Jr., director of CMU's Environmental Technology Center.

U.S. Steel was already adding bacteria to its wastewater treatment plant two years ago when CMU got involved at the invitation of the late U.S. Steel President Paul Wilhelm, a CMU trustee. The bacteria fed on carbons, so they attacked the compounds in oils, greases, cleaners and caustic solutions that made it into the wastewater produced at Gary's west end, where sheet steel is coated and finished.

"For all intents and purposes, they're food for bacteria," said Matthew S. Blough, a program manager at the CMU center.

The problem was U.S. Steel wasn't using enough of the right kinds of bacteria and wasn't adding them early enough in the wastewater treatment process for the germs to do their job. Once Minkley and Blough identified the right bacteria for the job and recommended adding them earlier, CBOD violations dropped.

Minkley now hopes to use bacteria to solve other problems for U.S. Steel facilities in Pittsburgh. The Pennsylvania Department of Environmental Protection has tentatively approved a pilot project this spring to test the effectiveness in a new setting.