Neenah Paper steams up.

Neenah Paper, based in Alpharetta, Ga., is using green steam to provide energy for its Neenah, Wis., mill.

The company estimates that it will purchase 350 million pounds of steam--a byproduct of a wastewater recycling process--per year to dry paper during manufacturing and to heat the mill. Neenah projects that this will reduce its natural gas consumption by 80 percent annually.

By reducing natural gas consumption, Neenah will also decrease its carbon dioxide emissions by 80 percent, or 150,000 metric tons.

The state of Wisconsin declared the steam "green" because it is derived from a renewable, organic source: wastewater sludge from paper mills.

Minergy Corp., a processing facility based in Neenah, Wis., developed the innovative method to recover the mineral content of the sludge and transform it into beneficial uses like steam, electricity and glass aggregate.

"The steam is used to pre-dry the sludge," Terry Carroll, Minergy general manager, says. The solids are then melted in a glass furnace. "This leaves behind inorganic mineral components that flow from the furnace as liquid glass, which can ultimately be used in various commercial applications. The heat produced by the melting process is recovered in a generator, which co-produces more steam. It is also used to power a turbine generator, which in turn generates electricity. It is truly a full-circle process," Carroll says.