You may find it difficult to get excited about scrap-tire disposal, but bear with me as we take a look at what the future holds for this somewhat sticky problem. And rest assured, it is a problem. Despite the fact that tire mileages continue to increase with new technology and retreading advances, record numbers of tires are being removed from service due to the ever-growing number of vehicle registrations.
While worn out tires are not considered inherently hazardous and don't create toxic waste even when burned, they do account for nearly 2% of the solid waste generated annually in the U.S. And the issue of solid waste disposal has become a high-visibility issue.
Last year, scrap tires were used primarily to generate tire-derived fuel (TDF). Burning a single scrap tire from a passenger car produces about 300,000 Btus, equal to approximately 2 gal. of fuel oil.
For economic reasons, however, we can't keep up with the amount of scrap tire we're currently generating, let alone what we've already accumulated. Since most tires are replaced locally, it's logistically difficult and expensive to transport them to the relatively few facilities equipped to burn TDF. In addition, tires are low-density (high cube) freight, and there are often no backhauls from the rural TDF customer destinations, making it an expensive haul.
According to Dan Pyanowski, team leader, safety, health & workers' compensation at Goodyear, another obstacle to increased use of TDF is that special equipment is usually required for efficient handling and combustion of tires. Most potential users find that such large capital expenses can only be justified when opening a new facility or as part of a large-scale renovation.
Civil engineering applications rank second in terms of volume of scrap tires used. They can be shredded and applied as road-fill, sub-grade backfill, as leach fields surrounding septic systems, and in landfill leach collection systems.
A common misconception is that rubber from scrap tires is often reclaimed for use in new tires. This was a common practice in the production of bias-ply tires years ago, but the increased construction complexity and use of different specialty rubber compounds in modern radial tires generally precludes this.
Some equipment formerly used in reclamation operations now produces ground or crumb rubber consisting of uniform size granules with wire, nylon, and other reinforcing materials removed. This material is used in a wide variety of products, including asphalt roofing, coating and sealing products, flooring tiles, energy absorbing pads, sports surface, and many types of molded products.
Currently, 37 states ban whole tires and 9 states ban any form of tires from landfills. Donna Jennings, manager, corporate issues and community relations for Goodyear, says a number of states also provide grants or loans for developing and sustaining viable local markets that address the annual generation of scrap tires as a productive resource. It's important to collect and use scrap tires soon after they're removed from service. Once they're placed in stockpiles, the likelihood of productive use is considerably diminished.
The RMA Scrap Tire Management Council, which serves as the focal point for industry concerns, has two primary goals. It wants to create markets and options for properly managing 100% of the scrap tires generated in the U.S., as well as make use of all existing scrap-tire stockpiles. For additional information and updates, visit the organization's web site, www.scraptire.org.