Once a Pollutant, 'Scrubber Sludge' Finds a Market. The Wall
Street Journal, October 5, 1998, ppB1,B2.
Power companies that have been using "scrubbers" to remove
the sulfur and fly ash coming out of their stacks are now selling
this waste to farmers and construction companies instead of
dumping it into landfills.
Two companies, Caraustar Industries and Babb Cellular
Concrete use the sulfur and fly ash to make construction products
such as wallboard and concrete.
Farmers are also buying the residue-called "scrubber
sludge"- because it helps increase crop yields. "Wherever you put
that stuff," said Ken Curtis, owner of a fertilizer business in
Illinois, "it just greens up."
In the past, power companies usually buried the sludge in
landfills, incurring liabilities. Now the Tennessee Valley
Authority makes from $6 to $10 million annually on sales of the
byproduct. "We're turning a deficit into a positive number," said
Cheri Miller, a TVA marketing specialist.
Ralph Woodward, a farmer from Carlisle, Indiana has a farm
by a power plant. Woodward thought that the scrubbing process
mandated by the Clean Air Act would result in a sulfurous sludge
that would probably improve the soil. He asked the officials at
the plant if he could have some because they were just dumping
it. "They just ignored me," said Woodward. He then donated
$50,000 to Purdue University to test his theory. He persuaded
soil scientist Darrell Norton to test his theory. "If this old
dumb farmer makes a claim that [sludge] works, they don't pay
much attention to you," Woodward says. "But if Purdue does it,
that it authentic."
Dr. Norton found that the sludge could increase crop yields
and reduce water-pollution runoff by increasing the soil's
capacity to hold rainwater.
The use of the sludge on some farmland has been approved by
federal and some state environmental agencies. It has been slow
to sell however. "It's an education process. Farmers have never
heard of it."
The construction industry also was looking at ways to use
the sludge containing calcium sulfate. The mineral, also known as
gypsum, is the raw material used to make wallboard. Some
manufacturers were mining the mineral from distant locations at
A power plant near Jacksonville, Florida began selling
sludge to farmers in the late 1980s. Soon after, a wallboard
company bought their entire output. "If we had more, they'd
probably take that too," says Jay Worley, an official at the
Indianapolis Power and Light Company sells about 300 tons a
year from one plant. Some of their other plants are being
upgraded to produce higher quality sludge. "When you are getting
paid for byproduct, you can afford to spend more money on it,"
said Jim Meiers, the utility's chief scientist.