Minergy’s Fox Valley Glass Aggregate Plant solves environmental problems

From Wisconsin Energy’s Current Newsletter April 13, 1998

Imagine a technology that can reduce landfilling in a county by two-thirds while creating two high-demand products, using a renewable energy source, and improving air quality. Engineers at Minergy Corp. not only imagined such technology, they designed and built it too.

After several years of research and development, Minergy’s Fox Valley Glass Aggregate Plant in Neenah begins full operation this month. The $45 million plant recycles 350,000 tons of paper sludge annually, melting the sludge in a glass-fired boiler that produces two products – steam for the P.H. Glatfelter Co., a Neenah paper mill, and glass aggregate, a glasslike substance used for sandblasting grit, roofing shingle granules and in asphalt production.

“Building this plant has given us the opportunity to expand our relationship with some of Wisconsin Electric’s largest customers, the paper mills, and help them to truly solve some significant environmental problems,” says Terry Carroll, regional manager for Minergy.

The plant, which employs 24 people, also is improving the environment in the Fox Valley region. By recycling the paper sludge instead of placing it in a landfill, Minergy’s Glass Aggregate Plant preserves 10 Acres of green space per year. Truck traffic and the resulting emissions have been reduced by about 450,000 miles per year, since the plant is located near sludge suppliers. And the operation of P.H. Glatfelter’s existing steam boilers, which have higher emission levels than the Glass Aggregate plant, will be reduced by 90 percent.

“Its a win-win-win situation,” says Lenord Leverence, Winnebago County solid waste director. Winnebago County’s Solid Waste management board selected Minergy’s proposal to build the Glass Aggregate Plant as part of its effort to pursue alternatives to landfilling paper sludge. The benefits are even greater, since paper sludge accounts for two-thirds of the waste stream in the county.

Eight area paper mills operated by Wisconsin Tissue Mills, P.H. Glatfelter, Kimberley-Clark, Ponderosa Fibers and Gilbert Paper supply Minergy with paper sludge. Paper sludge is wood waste which consists of paper fibers that are too short to be recycled into new paper. It also contains large quantities of clay, making the sludge practically impossible to reuse in paper making. At the Glass Aggregate Plant, the sludge is pre-dried, then melted at high temperatures in a cyclone boiler similar to the kind of boiler used in some power plants. High temperatures convert the clay component of the paper sludge into glass aggregate, while the heat recovery system uses energy from the wood fibers to produce steam.

Minergy’s glass aggregate technology is patented worldwide. It also owns the technology used at Wisconsin Electric’s lightweight aggregate plant in Oak Creek. Minergy also owns and operates four other commercial facilities: Provag Aggregate Plant, Geetruidenberg, Netherlands; VIT sludge treatment plant, Hengle, Netherlands; and the Mid-City and Motor Casting Foundry sand reclamation plants, Milwaukee.

Several organizations already have recognized Minergy’s innovations and positive impacts with awards. In 1997, while the plant was under construction, Wisconsin Manufacturers and Commerce Association presented Minergy with its “Business Friend of the Environment Award,” and both the Wisconsin Recycling Markets Board and the Wisconsin Department of Natural Resources awarded grants to Minergy for the project.