THE MARKET FOR SCRAP TIRES just keeps on trucking. A new report by the Rubber Manufacturers Association (RMA), Washington, D.C., shows that the number of newly discarded tires that are being reused continues to increase. Meanwhile, the number of scrap tires in stockpiles, which often consist of older tires, continues to dwindle, the “U.S. Scrap Tire Markets 2003” report says.
Of the 290 million scrap tires that were generated in 2003, 80.4 percent, or 233 million, went to an end-use market, according to the RMA's biennial report on scrap tire markets. The numbers represent the continuation of a steady increase that has taken place since RMA began the study more than a decade ago. For example, only 11 percent of the 223 million tires discarded in 1990 were reused. By 1996, just more than 62 percent of the annually scrapped tires were recycled.
Chaz Miller, state programs director for the National Solid Wastes Management Association, Washington, D.C., says the increased recycling rate is due in large part to RMA's efforts during the past 15 years to promote and open up scrap tire markets. “They've kept at it very effectively and steadily,” he says, noting the reuse rate should continue to be strong for the immediate future.
The most frequent reuse of scrap tires in 2003 was as tire-derived fuel (TDF). More than 44 percent — or 130 million — of the tires discarded that year were used to produce TDF, which comes in the form of rubber chips, according to the study. Cement kilns, pulp and paper mills, and utility and industrial boilers are among the facilities that use the fuel.
The second largest market for scrap tires in 2003 was the civil engineering field, which used 19.4 percent of the tires, the study says. Civil engineering applications included leachate collection and gas venting systems in landfills, drain fields for septic systems, subgrade fill in highway embankments, and backfill for walls and bridge abutments.
The ground-rubber market was the third largest scrap tire reuse market in 2003, using just less than 10 percent of the tires. Tires were used to create ground rubber that was used in rubber-modified asphalt, running track surfaces, dock bumpers and railroad crossing blocks, among other applications.
Just more than 9 percent of 2003's scrap tires were disposed of in landfills, and the fate of 10.3 percent of the tires is unknown, the study indicates.
While the annually generated scrap tires are finding more markets, the number of older, discarded tires in stockpiles is decreasing. In 1990, about 1 billion tires were in stockpiles, which are susceptible to fires and can become breeding grounds for vermin, the study says. However, a steady decline has ensued over the past 13 years as many states have begun scrap tire management programs. In 2003, about 275 million tires were stockpiled, the RMA's report says.
More than 90 percent of the stockpiles are concentrated in 11 states: Alabama, Colorado, Connecticut, Michigan, New Jersey, New York, Ohio, Pennsylvania, Texas, Massachusetts and Washington. Three of the states — Alabama, Michigan and New York — passed legislation in 2003 intended to decrease the stockpiles, according to the report, which adds that Ohio is “making progress.”
“Whether any of the other major stockpile states will be able to develop abatement programs anytime in the next two years is very uncertain,” the report concludes.
One challenge to decreasing stockpiles can be the advanced age of the tires. “Some markets are available to stockpiled tires, including some TDF and civil engineering applications,” the report says. “However, other markets are precluded by the condition of stockpiled tires.”