Dye is used to color the chips. It is reported that after one and one-half years, the dye is still on the chips. Safety Soil of Carmichael, California produces a similar playground gravel substitute made from tires. They claim their product will not harbor sand fleas, will not splinter or deteriorate like wood, and will not get into childrens’ ears or noses as will pea gravel. Safety Soil is manufactured entirely from nylon tires with the steel beads removed. Additional advantages include its ability to drain water, its cleanliness and softness, and the fact that it doesn’t need replenishing. Safety Soil serves only the northern California market because shipping costs are around $400 for eight-ton loads, Shipping to southern California costs over $1,000 plus for 15.5 ton loads and is not economical for the longer distances (39). Cushion-Turf of Illinois also manufactures a similar product. Advantages of the tire chips are that they provide a better cushion than the standard materials such as asphalt, stone, and wood chips. Their ability to drain water, stay clean, and their long life are also attributes. Playground tire chips, when longevity is considered, can be competitive with alternate materials, Alternate materials generally range from $15 to $35 per ton. The higher initial cost of tire chips compared to other materials may discourage the use of these chips for playgrounds. e) Sludge Composting. Another use for tires that have been shredded is as a bulking agent in the composting of wastewater treatment sludge, The two inch square chips are mixed with the sludge to maximize air flow through the compost pile. The chips are then removed from the compost and recycled prior to its sale or use. Tire chips are more nearly uniform than the most commonly used alternate material, wood chips, which results in more complete and odor-free composting, The initial cost of tire chips is about three times that of wood chips. Since tire chips don’t degrade, however, they can be completely recycled; whereas, about 25 to 35 percent of wood chips are lost to degradation with each batch, Shredded tire chips were used successfully for five years as a bulking agent for sewage sludge composting in Windsor, Ontario. The Windsor facility is a 24 million gallon per day wastewater treatment plant. Sludge composting had been performed since 1978. The compost was used for landfill cover material, landspreading, greenhouse soil conditioning, and other miscellaneous uses. Tire chips were used to replace about one-third of the wood chips normally used at the Windsor facility. The tire chips were screened out and reused, so that no additional new chips were required. About 30 percent of the wood chips were lost to the compost each cycle (40).
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