MADISON COUNTY TO USE SCRAP TIRES
By BOB MESSINGER
Old tires cause special disposal problems. Nationally we generate over 270 million scrap tires each and every year. New York State alone produces between 15 to 20 million waste tires annually. It has been estimated that there are over a billion scrap tires stored illegally throughout the United States. A NYSDEC report from November 1999, identified 116 unpermitted and unregistered waste tire stockpiles thought to contain more than 23 million tires within the State.
These old tires not only present an eyesore, they can also become a danger to the environment and when filled with water provide a great nesting place for mosquitoes who, in turn, help spread diseases like the West Nile Virus. Tire fires are a real concern since they are very hard to extinguish and pollute air quality. Tires are tough and durable and these same properties that give safe rides and long service make disposal of them very difficult. Landfilling old tires is almost impossible. Landfills don't like to handle them since they don't compact as easily as municipal solid waste, and (more importantly) they can "float to the top" causing damage to landfill covers. In fact 35 states ban whole tires from landfills. In addition, landfill tipping fees make this method of disposal costly. Presently it seems that the most popular method for tire disposal is the use of tire derived fuel (TDF). Contrary to popular belief, incineration of tires and tire chips under proper controls has proven environmentally safe. But, public opposition continues to curtail this method of disposal. Old tires have been ground and used to build tennis courts, running tracks, and even as rubber modified asphalt for roads but the economics of these uses are debatable. One of the biggest problems with breaking down old tires is the amount of steel they contain - each radial passenger tire will have 2.5 pounds of steel in it. It is costly to extract the steel from the rubber. With the exception of truck tires (15% of the tire market) re-treads seem to be a thing of the past. One promising area for disposal seems to be use in civil engineering applications that involve replacing conventional construction material like roadfill, gravel, sand, or dirt with scrape tires and tire chips.
Madison County, located in the middle part of the State, has been given permission by NYSDEC to use old tire chips in the construction of their landfill expansion. A modern "double lined landfill" is designed to prevent any leachate (contaminated water that passes over or through garbage) from reaching any water supply. It would typically be constructed with a layer of 24" of clay upon which a synthetic plastic liner would be placed. Above that, an additional 12" of clay is placed and another synthetic liner covers that layer. New York State regulation then requires a primary collection layer to be placed over that liner. It must have a minimum thickness of 24" of gravel to protect the underlying liner material and leachate collection plumbing. And typically, a frost protection layer of 12" of fill is placed on top of that. Madison County proposed to replace 12" of gravel in the primary drainage layer with 18" of tire chips. They also got permission to use tire chips as the frost protection layer (see diagram). Their consulting engineer, Barton & Loguidice proved to DEC that tire chips will ensure proper hydraulic operation of the leachate collection system, meet the gradation requirements, pass permeability tests, and withstand anticipated loading requirements. They pointed out that installation of tire chips is much like gravel and can be placed to proper grade using a low ground pressure dozer. It was felt that rubber tired equipment could be used in this process even though old steel belts could adversely affect vehicular tires. They also recommended that the tire chips be compacted with smooth drum rollers to create as smooth a surface as possible. B & L also pointed out that using tire chips in the frost protection layer offers more insulation than soil.
Some of the other considerations when replacing soil with tire chips were stability, compressibility, water quality, protection of the synthetic liner from puncture by old steel belts in the chipped tires, landfill fires, insect breeding grounds, and durability. In each case, tire chips either measured up to standards or a common sense solution to any potential problem was reached.
This 7 acre project is expected to utilize over 1,000,000 scrap tires from the vast stockpiles that have been built up. Those million tires won't act as breeding grounds for unwanted insects and be subject to polluting fires. And, using the tire chips will provide some economic benefits as well. It appears that Madison County can save up to $120,000 by replacing construction material with scrap tires. It should be a "win-win" project providing both environmental and economic benefits.
Madison County's use of tire chips is not totally unique. Tire shreds have been used in California for both gas collection and leachate collection layers in landfills. They have been used in Ohio for leachate collection layers. In New York State, tire chips have been used for road base, and in landfills as daily cover, gas collection trenches, and leachate collection layers. The Chautauqua County landfill uses them as daily cover and as backfill for gas collection trenches. Seneca Meadows Landfill outside of Waterloo uses them as part of their leachate collection system as does the High Acres Landfill in Monroe County. Highland Landfill in Allegany County utilizes tire chips as both road base and will use them as backfill for gas collection trenches. Delaware County's landfill and the Modern Landfill in Niagara County use them in their leachate collection systems.
Disposal of old tires will continue to be a major challenge for solid waste managers. New York's governor, at the urging of state and national environmental and industry leaders, has recently formed a special task force to continue to study the methods for tire disposal. The Center for Integrated Waste Management at SUNY Buffalo and Empire State Development are researching their use as a replacement for stone in septic system leach fields. 13 other states are investigating the potential uses of old tire chips in studies and demonstration projects. It all suggests that the issue of scrap tires is becoming more prominent for regulators and that beneficial use is seen as a real alternative.
Madison County's project won't solve the entire problem - but every little bit helps.