landfills: New Life for Old Tires in Iowa Landfill

Daniel R. Scott

Sometimes when you have a good idea, you just have to roll with it - despite the obstacles.

In planning its landfill expansion, Iowa City, Iowa, officials were inspired to use tires as the drainage layer in a new six-acre landfill cell.

Other landfill owners had experimented with using waste tires in landfill construction on a small scale, and the Iowa project members - Iowa City, Howard R. Green Co., Cedar Rapids; McAninch Corp., Des Moines; Tire Tech Environmental Systems, Muscatine; and the Iowa Department of Natural Resources (IDNR), Des Moines - believed that this large-scale use of waste tires would save money, provide a use for unwanted waste and reduce the need for other natural resources.

The Howard R. Green consulting firm designed the expansion. Typically, a landfill's drainage layer consists of one foot of sand or gravel, but in Iowa City's case, waste tires would be ground into smaller pieces, then used over the landfill cell base to collect liquids draining from the refuse. The liquids then would be pumped to the city's wastewater treatment facility.

IDNR awarded the city a $42,000 grant to cover the cost of one half of the purchase and delivery price of the waste tires from the tire processor, Tire Tech. In 1996, the state of Iowa allocated $15 million for a six-year waste tire management fund. This fund annually provides $300,000 in grants to encourage alternative uses for waste tires.

More than 1 million discarded tires collected from eastern Iowa are expected to be used in Iowa City's landfill, amounting to one third of the state's total annual number of disposed tires.

The sand drainage layer in the original landfill cell design was estimated to cost $190,000; the shredded waste tire drainage layer was estimated at $227,000. But the IDNR grant reduced the cost to $185,000, making tires less expensive than sand.

Shredding the 11,000 tons of tires stockpiled at the processor's site, which is located 60 miles from the landfill, and trucking the 500 semi-truck loads of shredded tires to the site were the project's major obstacles. However, by allowing five months to get the tires to the site, the city anticipates that this logistical problem will be averted. Iowa City estimates an $82,500 cost to shred and truck the tires to the landfill.

Performance of the shredded waste tire drainage layer also was a concern. Because shredded tires are more porous than sand or gravel, the tires will meet permeability requirements. However, the city was concerned about the effect of overburden waste and leachate on the tires over time.

Existing studies show that up to 100 feet of overburden waste does not significantly affect tire permeability and shows no affect of the chemicals leaching through tires. However, the city will semi-annually analyze the cell's leachate to ensure that no collection or chemical problems arise.

McAninch began cell construction in July, placing the tires in a 21-inch thick layer that is expected to eventually result in an 8-inch thick layer after up to 100 feet of refuse is placed on top of it. Construction was scheduled to be completed by November 1998.

One possible benefit from the shredded tire layer may be found in the added cell base liner. A discarded two-by-four piece of wood or a metal pipe can act like a spear through a sand layer, puncturing a landfill's base liner during placement and compaction. The shredded tires may act more like a shield to divert possible projectiles before they can penetrate the tire liner.

If the shredded tires function as well as anticipated in Iowa City's landfill, they will be considered in future cell expansion projects.

Acquisitions Biocorp Inc., Redondo Beach, Calif., has acquired Ccotrade, Unna, Germany, a manufacturer of fully biodegradable and compostable food service wear. It will be known as Biocorp-Ccotrade.

IESI NY, New York, has expanded its New York City presence by acquiring Brooklyn-based Spartan Dismantling Corp.'s asbestos transfer station and hauling assets.

The U.S. Department of Justice has informed Eastern Environmental Services Inc., Mt. Laurel, N.J., that a complaint will be filed in Eastern District Court of New York against its previously announced merger with Waste Management Inc., Oak Brook, Ill.

ENSR International, Acton, Mass., has acquired Galson Corp., Syracuse, N.Y.