PCB furnace shows promise

Minergy suggests river cleanup method less costly than landfill

By Ed Culhane
Post-Crescent staff writer

Contaminated Fox River sediments could be dredged and then melted in a glass furnace, destroying virtually all PCBs for less than the cost of landfill disposal, new data suggests.

Officials with the state Department of Natural Resources said new studies submitted as a public comment by Minergy Corp. are promising and could add a new dimension to the proposed river cleanup.

The DNR and the U.S. Environmental Protection Agency plan to issue a decision on the cleanup later this year.

“If it comes down to a tossup between putting it in a landfill and destroying it, our preference has always been to destroy it,” said Bruce Baker, the DNR official directing the cleanup.

In a group of studies completed during the final days of the public comment period that ended Jan. 22, Minergy concluded it could melt all 7.25 million cubic yards of contaminated sediment the DNR wants removed from the lower Fox River — during 16 years of dredging — at a cost of between $26 and $33 a ton.

This is the equivalent of a disposal cost and does not include the expense of dredging the sediments or treating the water removed from sediments.

But it compares favorably with the landfill disposal fees that topped $70 a ton during a dredging project near Kimberly in 1998 and 1999.

DNR officials believe they can dramatically reduce landfill costs during a whole river cleanup because of economies of scale and by using a pipeline to transfer sediment slurry to a landfill site, on the downstream end of the project, greatly reducing transportation costs. Still, landfill costs in the DNR’s feasibility study for dewatered sediment range from $15 a ton to $95 a ton.

Minergy, in a joint project with the DNR and EPA, built a pilot-scale furnace in Winneconne last summer and melted 10.7 tons of Fox River sediment, creating a shiny, black glass aggregate that tested free of contaminants. The EPA took test samples on all phases of the operation for two weeks, and shared the test results with the DNR.

The tests showed that 99.99 percent of PCBs were destroyed, said Bob Paulson, a DNR toxicologist. The furnace also destroyed all dioxins in the sediment without creating new ones in its emissions stack, he said.

“This is phenomenal destruction,” Paulson said. “We did not measure any dioxins in the stuff that came out of the pollution control equipment.”

Rebecca Katers of the Clean Water Action Council, the local environmental organization that is monitoring cleanup plans, reacted cautiously. She noted that the EPA emission tests will not be official until they have been subjected to rigorous quality assurance reviews.

Katers said pilot-scale projects sometimes offer promises not fulfilled by commercial-scale ventures. Should furnace technology be used on the Fox River, she said, the public should be offered guarantees about clean emissions.

“If this is all true, it would be a big benefit to the cleanup to have a permanent destruction of the PCBs,” Katers said, “but we need to see the proof, and we need assurances that if it doesn’t check out once a furnace is operating, that it will be shut down.”

Paper company officials were unavailable for comment on short notice Friday and Saturday.

In addition to the studies, Minergy joined with two other companies — J.F. Brennen, a dredging company in LaCrosse, and Earth Tech, an environmental consulting firm in Sheboygan — to present a conceptual design of a river cleanup using three industrial melters. The first would be located at Little Lake Butte des Morts, melting 600 tons of sediment and producing 250 tons of glass aggregate daily.

The other two would be located in a single facility near the Green Bay stretch of the river, melting 1,200 tons of sediment and producing 500 tons of glass daily.

The furnaces would be quiet, would not emit odors and would be housed within buildings about the size of a grocery store, said Terry Carroll, Minergy’s regional manager.

“It would be a pretty friendly building,” Carroll said. “There are not a lot of moving parts in something like this.”

Carroll said the company easily can market the 750 tons of aggregate that would be produced daily for 16 years. He said the company already is selling the 250 tons of glass produced daily at its sludge-burning plant in Neenah.

The aggregate can be used as construction fill, Carroll said, and as much as 40,000 tons are needed to build a single warehouse above grade. A four-lane highway can use 50,000 tons per mile.

“We have trouble filling large orders because we have a limited supply,” he said.

If all 7.25 million cubic yards of contaminated sediment from the Fox were melted in furnaces, Carroll said, it would produce 3 million tons of glass aggregate during the life of the project.

Ed Lynch, the DNR official coordinating the cleanup studies and the DNR response to the public comments, said the melter studies are good news for the agency.

“We left the door open to look at this as a possible remedy in the cleanup plan,” Lynch said. “It puts us in a favorable position. It allows two options instead of one (for dredged sediments) and it allows us to balance between the two.”

DNR officials said a mix of technologies remains a possibility. Paulson said the paper companies that are expected to pay for the cleanup would have to support the technology as would municipal officials in the Fox Valley.

Appleton Mayor Tim Hanna said Minergy’s concept sounded promising.

“If this works, it has to be better than landfilling the stuff,” Hanna said. “If you can get rid of it, rather than moving out of the river and into the land, isn’t that better?”

Ed Culhane can be reached at 920-993-1000, ext. 216, or by e-mail at eculhane@appleton.gannett.com.