Dozens of Great Lakes communities are trying to find ways to pay for removing contaminated sediment from bodies of water. Dredging silt full of pollutants from the bottoms of the rivers and lakes can cost tens of millions of dollars. In the third and final part of our series on contaminated sediment, the Great Lakes Radio Consortium’s Jonathan Ahl reports on what may be the only attempt in progress to find a new way to dredge toxic silt and mud:
Dozens of Great Lakes communities are trying to find ways to pay for removing contaminated sediment from bodies of water. The cost of dredging silt full of pollutants from the bottoms of the rivers and lakes can cost tens of millions of dollars. In the third and final part of our series on contaminated sediment, the Great Lakes Radio Consortium’s Jonathan Ahl reports on what may be the only attempt in progress to find a new way to dredge toxic silt and mud.
(ambient sound in the warehouse)
Two engineers are working in the back of a massive warehouse at Kress Corporation headquarters in Brimfield, Illinois. They are standing over a bin six feet wide and twenty feet long. It’s full of green water and thick brown muck. This is a replica of a river bottom and its sediment… — sediment that could contain pollutants including PCB’s, mercury, and lead.
(ambient sound – the dredger in action)
Crawling through the bed is a machine that houses a two-foot diameter disc. It looks like a Ferris wheel that scoops up its sediment passengers at the bottom of its rotation, and deposits it into a container next to the dredge just before dropping down to make another cut into the muck. Jim Sutor is an engineer with Kress Corporation. He says if the full size model works as well as this one-tenth size prototype, it will be much more efficient than the current method of removing contaminated sediment using a clam shell dredger – a bucket raised and lowered by a crane:
“It’s more of a continuous operation, so it’s more efficient than a
clamshell, where a clamshell goes down and takes a cut, brings it up, then puts it into something. Well this wheel is continually moving the whole time. It’s continually taking a cut.”
Sutor says the full size version of this machine will be able to dredge 1600 cubic yards per hour, and stir up less sediment into the water column than clamshell dredges. But not everyone is convinced that this new technology will do much to solve the problems that face communities looking to clean toxic areas.
Michael Palermo is a contaminated sediment expert with the U.S. Army Corps of Engineers. He says it’s risky to invest a lot of money on new dredging technology, especially considering dredging equipment already exists that can remove contaminated sediment from lakes and rivers.
“Well I think we know very well how to address these problems with technologies we have. The problem that we have is that some of the technologies that we would like to apply are very expensive, and we do think there is research needed, but there are ways to address the problems with the technologies that we have now.”
Kress Corporation is predicting their new dredge will be a more financially viable option to current machines. But they can’t prove it yet. The company is receiving federal funds to help with the development of the new technology. Illinois Congressman Ray LaHood says the one million dollars that is going toward the Kress Dredger is a good allocation of sediment remediation money:
“We know there are lots of bodies of water all over the country that are in great need of a piece of machinery like this to save lakes or rivers, or other bodies of water.”
However, some communities say the government is throwing away money on research, when that same money could be used to clean up their neighborhood waterways. They argue that existing technology is good enough to remove the contaminated sediments from their rivers and lakes. But officials at Kress Corporation say once their full sized prototype is in the water, it will be clear that the money was well spent. Those tests are scheduled to begin later this year. For the Great Lakes Radio Consortium, I’m Jonathan Ahl.