By Brian E. Clark
NEENAH – After nearly six years of superheating Fox Valley paper mill sludge and turning it into small chunks of glass for use in construction, Minergy hopes to soon begin applying a similar technology to “vitrify” suburban Chicago sewage and wastewater.
The $40 million plant under construction near Zion, Il. should start operating next year. It will be the first facility of its kind to melt sanitary district sludge, said Wally Kunicki, Minergy’s general manager and a former Wisconsin State Assembly speaker, and if it works as promised it could lead to new markets for the 11-year-old company.
Currently at Minergy’s $45 million Neenah plant, 1,000 tons of paper mill sludge — nearly all the sludge now produced in the Fox River Valley — is melted at 3,000 degrees every day to produce 200 tons of glass aggregate. Minergy, a subsidiary of Wisconsin Energy Corp., was originally created in 1993 to deal with ash from power plants. Like some of the glass aggregate produced in Neenah, the ash byproduct is sold for use in road construction.
Minergy executives hope government agencies and paper mills seeking to dispose upwards of 11 million tons of PBC-contaminated sediments in the Fox River will use Minergy’s expertise. The Fox River cleanup is expected to cost at least $400 million. Seven paper companies have been held responsible for the discharge of PCBs into the river from 1957 to 1971 during the manufacture and recycling of carbonless copy paper.
PCBs are polychlorinated biphenyls now banned by federal law. The Environmental Protection Agency has listed them as human health risks and potential carcinogens. PCBs also were used for many years in paints, plastics, pigments and dyes.
Minergy’s proposal is backed by the Sierra Club and other environmental groups, which say that vitrification – the process through which sludge, sediments, sewage and other wastes are turned into glass – is a far better alternative than putting the dredged mud in landfills. Minergy is also supported by Winnebago, Outagamie and Calumet county officials, who have endorsed Minergy’s plan as a safer alternative than burying it in landfills.
They cite tests conducted two years ago at a Minergy pilot furnace in nearby Winneconne that processed 60 tons of sediment. The EPA measured the results, which showed that PCBs were destroyed at a 99.999 percent efficiency rate.
“It doesn’t get much better than that,” said Kunicki. “That’s about the most stringent environmental standard you can have.”
Earlier this year, the Town of Vinland in Winnebago County filed suit seeking to block disposal plans by paper mills of PCB-laced sediments in a Georgia-Pacific landfill within its borders.
The town’s petition said the 748,000 cubic yards of contaminated sediments that could be stored at the Vinland landfill site would “create a public nuisance and a short-term or long-term environmentally unacceptable hazardous situation.”
After the suit was filed, an ONYX landfill site in Calumet County was chosen by the paper companies, G.W. Gladfelter and WTM1 Co. The Vinland suit was subsequently dropped.
“Vitrification permanently destroys the PCBs, landfilling does not,” Jennifer Feyerherm of the Sierra Club’s Great Lakes Program.
“We want to get the PCBs out of the river, but we support permanent destruction of the PCBs wherever possible and vitrification does that. With landfilling, the PCB problem never really goes away.”
Toby Paltzer, Outagamie executive, acknowledged that vitrifying sludge may be more expensive – at least in the short term. Minergy officials estimate it would cost between $40 and $60 a ton to vitrify the sediments.
According to a CH2M HILL Engineering study commissioned by several paper companies, the landfilling cost is an estimated $43 per ton. The report also said Minergy’s estimates were low and that Minergy’s plan would add $24 million to the first phase of the cleanup and add eight years to the project. The consultants said they also do not believe vitrification provides any overall environmental benefit and could pose air pollution problems of its own.
“CH2M Hill, as well as the Wisconsin DNR and U.S. EPA, is confident that engineered landfills are an environmentally safe, long-term solution for disposal of sediments containing PCBs,” the study said.
“Sticking the stuff in a landfill instead of destroying the PCBs means it will be an issue that our grandchildren and great-grandchildren will have to deal with down the road,” he said.
In the mid-1990s, Fox Valley paper companies were faced with rising costs for putting sludge in landfills.
About the same time, Minergy engineers came up with a process to turn the sludge – clay coatings and wood fibers too short to be recycled into new paper – into glass aggregate, while also producing steam and electricity.
Local government officials embraced the idea, in large part because it reduced the waste stream to landfills by two-thirds. Paper firms signed on as a way to save money.
For more than a century, the lower Fox River has had one of the world’s largest concentration of pulp and paper mills. Before wastewater treatment was required by law, the river was often the dumping ground for paper mills, depleting the stream’s oxygen and killing nearly all its fish – except carp.
“Before the 1950s, it wasn’t uncommon to see large sludge mats floating down the river,” said Robert Paulson, a Minergy official who worked for the state DNR for 13 years.
After the passage of passage of the Clean Water Act in 1972 – which limited discharges into the river – game fish returned to the Fox River, which now boasts major walleye tournaments.
Advisories from state agencies warn, however, that eating fish from the river could be unhealthy because of PCBs deposited in the river.
The first stage of a $66 million clean-up program – which would use landfilling to store PCB-laced sediments – began in September in Little Lake Butte des Morts and has already generated controversy.
Winnebago County Executive Jane Van De Hay said leachate from the Winnebago County landfill, which was used in earlier sediment disposal tests, has PCBs in it.
“Turning the sediment into glass using Minergy’s technology would destroy not only the PCBs, but mercury and lead, too.”
“We want the PCB-contaminated sediments taken care of in the most cost-effective and permanent way,” she said. “We are optimistic that something can be worked out.”
Len Leverence, head of Winnebago County’s solid waste division, said officials will meet Oct. 25 with their attorneys to determine how they should proceed. Options include a suit, he said.
“We do not want that sediment in any of our county landfills, that’s the bottom line,” he said.
Paulson said his company is not counting on processing the sediments from the first phase of the removal process. But if Minergy gets the contract to vitrify the PCB-polluted sludge in the northern end of the Fox River, Paulson said a vitrification plant could be built in 16 months and be ready for operation in two years. A decision could be made early next year.
“It would not slow that phase down,” he said, estimating that it would take between 10 and 15 years to treat all of the contaminated sludge.
In addition to the Fox River, he said other PCB-contaminated sites in the state, including die-casting plants in Sheboygan and Milwaukee, could be candidates for Minergy’s technology. There are many other polluted sites around the nation and globe, he added.
Winnebago County’s Leverence said his county’s experience with Minergy and its vitrification plant over the past five-plus years has been excellent.
Minergy’s boiler – which consumes 250 tons of coal a day – generates 300,000 pounds an hour of steam that goes directly to the adjacent P.H. Glatfelter paper plant to run its machines. By using Minergy steam, Glatfelter was able to take its less efficient boilers off line, Minergy’s Paulson said.
“We are intimately connected to their facility,” added Paulson, who noted that Glatfelter makes specialty writing and publishing papers at the Neenah facility.
In addition, he said Minergy sells six megawatts of electricity – – enough to power 17,000 homes – back to Alliant Energy for use in the regional grid.
Paulson said the Minergy plant, which employs 24 people and operates around the clock, saves 10 acres of open space a year and has reduced truck traffic by 450,000 miles annually.
Kunicki and Brian Jensen, general manager of the North Shore Sanitary District, said environmental concerns are also the reason behind the North Shore Sanitary District’s decision to sign on with Minergy.
“We weren’t considering a land application because of pathogens, heavy metals and worries about contamination of ground water and soils,” said Jensen.
“We were also looking for a beneficial reuse of what was left over and this fit the bill,” he added. “We looked at Minergy’s smelter and liked what we saw for a lot of reasons.
“We think it’s a great way to deal with what is basically a hazardous waste. It also makes sense to us from a business perspective, too.”
Kunicki said he hopes the Zion plant, which will heat the sewage sludge and waste water residue to 2,000 degrees to turn it into glass, will be a model for other municipalities around the country and globe.
“Now, most of it goes to landfills or is used as a fertilizer on greenspace or feed crops, but not on plants humans will consume,” he said.
“It just makes more sense to destroy all those pathogens,” he said. “The end product is inert, it won’t leach out and there is a beneficial reuse for the glass byproduct.”
Kunicki said Zion plant could process up to 35 tons of dried sewage sludge a day and produce 6,000 tons of glass a year.
“We’ve already had interest from Singapore, Poland and Russia,” he said. “We just need a reference plant that is up and running.
Kunicki said Minergy wants to make sure the plant operates as promised.
“Waste-water treatment tends to be very conservative and redundant because the people who run the facilities have been sold a lot of mousetraps over the years that did not work,” he said.
“We want to make sure we get this right,” he said.