$49M dredging under way on Ottawa River

A dredge works the Ottawa River near Stickney Avenue. THE BLADE/ANDY MORRISON Enlarge | Photo Reprints

One of the largest cleanups in Great Lakes history kicked into high gear yesterday in North Toledo.

At 8 a.m., crews began operating dredges on 24-hour cycles along the Ottawa River, said Scott Cieniawski, U.S. Environmental Protection Agency project manager.

Through October, the $49 million project will be operated around the clock except for Sundays, he said.

The system was put into place Monday, after passing a test run Saturday. Sixteen hours of dredging was done Monday and Tuesday before the 24-hour cycles began yesterday, Mr. Cieniawski said.

The river's most polluted sediment is being piped through a water-treatment system specially designed for it on the north side of Toledo's Hoffman Road landfill, said Bob Rule of de maximis inc., an environmental consulting firm hired by a group of companies paying for half the work.

After screening out golf balls, wood chips, and large chunks of debris, the soupy mixture is passed through a filtration system that removes bulk sediment.

A polymer is added as a thickener to help bind small particles together for easier removal, Mr. Rule said.

To remove even more of the free-flowing dirt, the thinned-out liquid is pumped into socklike mesh bags 300 feet long, the length of a football field.

Those bags screen out particles and let water pass through, much like coffee filters.

They're 30 feet wide, and swell to a height of 6 feet. Workers stomp on the bags to loosen up the silt and keep water gushing out.

The water is treated on-site before it is returned to the river, Mr. Rule said.

The Ottawa is a Lake Erie tributary long viewed by the Ohio Department of Health and Ohio Environmental Protection Agency as the state's most polluted waterway.

A silt curtain has been installed in the river near I-75 to catch errant sediment before it can reach Lake Erie's Maumee Bay, Mr. Rule said.

In the aftermath of litigation initiated in 2004 against 13 companies by the U.S. Fish and Wildlife Service, a consortium of seven businesses known as the Ottawa River Group offered to pick up half the costs. The city also was named as a participant in that settlement.

The seven businesses in the consortium are DuPont, Allied Waste North America, GenCorp Inc., Honeywell Inc., Illinois Tool Works Inc., United Technologies Corp., and defunct Chrysler LLC, also known as OldCarCo. The city is providing support with its donation of landfill space.

The government's half is coming from the Great Lakes Legacy Act that Congress started in 2004 for removing polluted sediment from Great Lakes harbors and tributaries.

Only one other project in that program - the 2006-2007 cleanup of the Ashtabula River in northeast Ohio - has been awarded more money.

The Great Lakes region's largest dredging project for environmental restoration is in Wisconsin's Fox River. It is being done with money allocated by the U.S. EPA's Superfund program, Mr. Cieniawski said.

The Ottawa River project initially was scheduled to take two years. The timetable was expedited after dredge operators persuaded those in charge it would be more efficient having three machines on site instead of one. Two are constantly in use and one is on standby, Mr. Cieniawski said.

The dredges, guided by GPS technology, dig up two feet of sediment on each pass. They are canvassing a 5 1/2-mile stretch of the river west of Suder Avenue.

Mr. Rule projects 230,000 to 250,000 cubic yards of polluted sediment will be removed, as much as seven feet of the riverbed.

All but 10,000 cubic yards of it will be buried in the landfill. Anything with chemicals too harsh for the Toledo dump is to be sent off for disposal at a hazardous waste site in Wayne County, Mr. Cieniawski said.

Contact Tom Henry at:

thenry@theblade.com

or 419-724-6079.