From PCBs to pavement

Posted Sept. 12, 2003

Asphalt-granule mix could be one road to Fox PCB solution

By Alex Hummel
of The Northwestern

It looks like a normal slab of asphalt hot out of the mixer, but the recipe features tiny black granules of glass that could become a permanent solution for cleaning up contaminated Fox River sediments.

Road makers on Thursday laid a span of special asphalt at Johnson Trucking in Neenah to demonstrate a possible landfill-free future for PCB-contaminated muck.

State Department of Transportation engineers have approved the recipe for asphalt containing glass aggregate, created by heating paper mill sludge and other waste products at high temperatures.

The hope is PCB-contaminated sediments scooped out of the Fox River will yield a similar product to be used in road asphalt. At $25 to $55 a ton, the cost of the glass aggregate versus quarried rock used in road building will likely be the ultimate determinant.

Minergy touts glass aggregate as an asphalt ingredient because the shape of the granules leaves the right sized air pockets in roads. The air pockets help the right amount of moisture soak in. Too much water on the surface can warp the road. If too much water is absorbed, the road can crack.

Thursday’s demonstration could foreshadow one solution to the PCB problem – stronger roads.

The state isn’t 100 percent sold on using glass aggregate from river sediments in its roads. But Busalacchi said the state is “very encouraged” by the concept and progress.

“Having trucks run up and down it on a regular basis is going to really tell the tale,” said Wisconsin DOT Secretary Frank Busalacchi, who was on hand for the demonstration, led by Neenah’s Minergy Corporation.

“We let the road projects so obviously we’re going to have to be the lead on these things,” Busalacchi said.

Local governments in the Fox Valley are warming up to vitrification — the process of cooking sludge or sediment down into glass — instead of burying PCB-contaminated sediments in local landfills.

The Winnebago County Solid Waste Management Board has already voted in support of vitrification as a Fox River cleanup option. Solid waste officials and Minergy representatives hope to encourage neighboring towns, cities and counties to do the same.

Chuck Farrey, a town of Vinland and Winnebago County board supervisor, is among vitrification’s supporters. His town may be nearing a legal fight over planned disposal of Fox River PCB sediments in a Georgia Pacific landfill there.

Officials are concerned about potential leaching of PCB material into groundwater. The town has a tentative Oct. 15 public hearing on tap including a Minergy presentation.

“I think it’s going to be a health and safety issue,” Farrey said. “And if there are options (to landfilling) that are viable, they’ve got to be explored.”

Minergy Regional Manager Terry Carroll said his company will keep close watch on the Johnson Trucking asphalt week by week to monitor for any cracking or other stresses.

“The demonstration today will show that, yes, we will have sufficient markets for the material, and we don’t have to go any further than northeast Wisconsin,” Carroll said.

Alex Hummel: (920) 426-6669 or