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Shredded tires a cheap, environmentally friendly way to cover landfills
James E.
Kloeppel, Physical Sciences Editor
217-244-1073; kloeppel@illinois.edu
9/28/2005
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CHAMPAIGN, Ill.
— Placing shredded tires on top of – rather than in –
landfills can save money and benefit the environment, researchers from
the University of Illinois say.
Timothy Stark, a professor of civil and
environmental engineering at the University of Illinois at Urbana-Champaign,
and Krishna Reddy, a
professor of civil engineering
at the University of Illinois at Chicago, recently evaluated the
use of shredded tires as a drainage material in waste-containment systems.
Shredding tires into chips roughly 4 inches by 6 inches, they report,
offers a simple and cost-effective way of providing drainage for modern
landfills, remediating older landfills, and disposing of mountains of
scrap tires.
Nearly 280 million tires are discarded annually in the United States.
Piles of worn-out tires can become eyesores and breeding grounds for
mosquitoes. In landfills, intact tires can collect methane (produced
by decomposing waste) and create potential fire hazards. Over time,
these tires can work their way to the surface, where they can damage
liner covers and cause increased leachate production that could contaminate
groundwater.
“As a result, many states now require that scrap tires be shredded
into chips prior to disposal,” Reddy said. “Instead of simply
burying those chips with all the other waste, we suggest using them
as a drainage layer in both modern and abandoned landfills.”
The drainage layer prevents water from percolating through the waste
and polluting the ground water, Reddy said. Typically, the drainage
layer is composed of sand or gravel, which must be purchased and transported
to the landfill.
To investigate the feasibility of using shredded tires as a surrogate
drainage material, scrap tires were shredded and distributed as drainage
layers at two landfills: one in southern Illinois and the other near
Chicago.
Stark and Reddy monitored the two sites for such characteristics as
settlement, erosion, flow rates and water quality, and compared them
with conventional sites that used sand or gravel. The researchers also
measured the permeability of tire chips in the laboratory.
“Our research shows that replacing the sand or gravel with a layer
of tire chips works just as well and costs less,” Stark said.
“The tires must be shredded for disposal anyway, so there is fairly
little expense compared to buying and hauling sand or gravel.”
The remediation of old landfills could consume huge quantities of scrap
tires. “A drainage layer one-foot-thick covering one acre requires
about 70,000 tires,” Stark said. “A typical landfill covers
10 to 20 acres, and there are about 150 abandoned landfills in Illinois,
alone, that are in need of some degree of remediation.”
Shredded tires also could be used as backfill behind retaining walls
and in other locations where sand or gravel is commonly used, the researchers
report.
The work was funded by the Illinois Department of Commerce and Economic
Opportunity.
Editor’s note: To reach Timothy Stark, call 217-333-7394; e-mail: tstark@illinois.edu.
To reach Krishna Reddy, call 312-996-4755; e-mail: kreddy@uic.edu.
