If tire recycling seems like an easy task, consider the millions of tires worldwide that are sitting in empty lots, back yards and river beds. The problem is that the very thing we like in tires -- tough, durable construction -- makes them a challenge to recycle.
But that's not to say that tires can't be recycled, and millions of them are every year. It's simply a matter of finding uses for old tires, and getting them to a tire recycler.
Fortunately, technology has advanced to the point that tires can now be profitably recycled into many useful products.
The Trouble with Tires
Tires that are simply thrown away are a serious environmental problem. The sheer volume of tires discarded each year -- almost 300 million tires in the United States alone -- makes safe disposal difficult.
Discarded tires are an ideal breeding ground for mosquitoes and other disease-carrying animals because their hollow, rounded shape holds water for a long time. When disposed in a tire stockpile, used tires are often burned outdoors, which creates an ugly black smoke that contains toxic compounds (due in part to the oil and other products used in manufacturing tires).
Tires are also a problem in landfills: Their hollow, rounded shape takes up valuable shape in landfills. Additionally, tires often don't stayed buried -- they have the unfortunate habit of trapping gases like methane and then "bubbling up" through landfills, ripping through landfill liners in the process.
How Are Tires Recycled?
Tire recycling and reuse have made great strides in recent years, partly due to environmental regulations and partly due to innovative technologies that have created new uses for old tires.
Civil engineers in particular have found a wide variety of uses for old tires. Shredded tires are used in constructing road embankments and below-grade fill; they can also be used as a vibration-reducing material for railway lines.
Ground-up tire rubber is also used as a road material or construction material when mixed with asphalt or concrete.
Because of its shock-absorbing nature, shredded tires make an effective ground cover for safer playgrounds, and as a material for running tracks and other athletic facilities. And the durability of tires make them ideal for reuse as dock bumpers, sidewalk material, roadway curbing and edging -- even speed bumps and highway crash bumpers can be made of old tires.
Because oil and rubber burn well, shredded tires are burned as fuel in some industrial processes. Tire-derived fuel, or TDF, is used in pulp and paper factories, cement kilns, electric utilities and other facilities. The EPA has stated that "emissions from tire-derived fuel are often less and generally within the same range as emissions from conventional fossil fuels," provided the burning occurs in a properly maintained device.
There are also a number of imaginative household uses for old tires. Tire swings, sandals, garden planters, furniture and artwork have all been created from scrap tires.
Tire Recycling: By the Numbers
According to the EPA and the Rubber Manufacturers Association, some 290 million tires are discarded in the United States each year.
Over 80 percent of these (about 233 million tires) are reused or recycled in some way. About 130 million tires are used annually as tire-derived fuel (TDF), making TDF the single biggest use for old tires.
Over 16 million old tires are reused as retreads, i.e., where new rubber is molded onto an old tire. Retreading tires uses much less oil and other resources than are used to create a new tire. Some 56 million tires are used in civil engineering projects like roadway embankments and the other engineering uses mentioned above.
How to Recycle Tires
Most car owners recycle their old tires at a service station or other facility that accepts old tires when the owner buys new tires. Additionally, some local governments sponsor tire collection programs, accepting old tires with "no questions asked."
The most environmentally aware way to recycle tires is, of course, to keep your tires in good operating condition for as long as possible. Follow smart, green car-maintenance practices like keeping tires properly inflated, rotating your tires, balancing your wheels, and aligning your wheels when necessary.