The National Gypsum plant in Shippingport, Pa., not only recycles 99 percent of its own waste, it recyles waste from a local power plant to make wallboard, earning it kudos from Pennsylvania Department of Environmental Protection (DEP) Secretary David E. Hess. Hess offered congratulations to National Gypsum plant officials on their pollution prevention efforts during a recent tour of the wallboard manufacturing facility.
"Ninety-nine percent of the content of the wallboard manufactured here comes from recycled material," Hess announced. "More than 440,000 tons a year of scrubber sludge from the Bruce Mansfield power plant doesn't go to a landfill because it is used here to make a product used by builders and homeowners everywhere.
Due to its recycling efforts, the company reduced wallboard waste by 8,960 square feet per day in 2001.
"This kind of story is repeated over and over again in Pennsylvania as companies and municipalities look for creative ways to reduce or eliminate waste, prevent pollution and lower their energy use," added Hess.
He noted that the 215 winners of the Governor's Environmental Excellence Award permanently reduced wastewater by 5.2 billion gallons, solid waste by 122 million tons and air emissions by 112 million tons. They saved more than 78 million kilowatt-hours of electricity, and reduced their own costs by $648 million.
The Bruce Mansfield facility burns more than 6 millions tons of coal annually and produces 56 million kilowatt-hours of electricity per day. The facility uses scrubber-style air pollution systems on its three stacks and produces up to 4 million gallons of scrubber sludge per day. The National Gypsum plant uses more than 1,200 tons a day of sludge from Bruce Mansfield.
The National Gypsum plant can produce 725 million square feet of wallboard per year. The plant ships an average of 3 million square feet of wallboard daily. Production began in November 1999, and the plant employs 105 employees.
The flue gas desulferization (FGD) sludge is conveyed to National Gypsum from the Bruce Mansfield facility on a one-and-a-half-mile-long conveyor belt. At the facility, it is dewatered and ground into a powder. The resulting material, called stucco, is blended with water and other ingredients to make a paste. The slurry is spread on a moving stream of cream-colored paper and then covered, sandwiched with another paper, or gray back, to be formed into wallboard at the facility's forming station.
The long, continuous sheet of wallboard then travels on moving belts and roller conveyors to the knife, where it is cut into specified lengths. The long "board line" is needed to allow the gypsum slurry time (about four minutes) to harden before it is cut. The cut wallboard panels are turned cream side up and sent into the kiln to dry.
edited by Sandy Smith ([email protected])