Photo courtesy of Vagawi
Every year, approximately 1 Billion tires are replaced due to wear and tear. Many of these tires end up in landfills, but the majority are burned or converted into Tire Derived Fuel. A growing number of tires are being recycled after they have reached the end of their useful lifespan.
Recycling tires is a tricky process, because tires are a hodgepodge of many different things:
A typical passenger tire contains 30 types of synthetic rubber, eight types of natural rubber, eight types of carbon black, steel cord, polyester, nylon, steel bead wire, silica and 40 different kinds of chemicals, waxes, oils and pigments. They typically contain 85% hydrocarbon, 10-15% iron (in the bead wire and steel belts) and a variety of chemical components.
Discarded tires are mostly inert, but their effects on the environment are largely unknown. When discarded in landfills, they pose a significant fire risk and they take up a lot of space. Even before they reach the landfill, a lot of tire rubber flakes off into the environment from normal wear and tear. The effects of this worn tire rubber haven’t been widely studied.
Old tires are a cheap and plentiful resource, so many different ideas have been proposed to put old tyres to practical use. In the 1970’s, several attempts were made to build artificial reefs out of discarded tyres. Those plans didn’t work out very well, because chemicals in the tires repelled marine life. Now, millions of tires are rolling around on the ocean floor and even causing damage to natural coral reefs.
More recently, tire recycling companies stepped in and found commercial uses for tire scraps. More than 80% of dead tires end up getting turned into Tyre Derived Fuel. When tires are burned along with coal and wood scraps, they can actually reduce emissions of some pollutants.
There are other uses for recycled tires – they’re used as an ingredient in road construction, as a replacement for pavement, to make rubber flooring, and as artificial mulch. A blend of liquid asphalt and “Fine Grind” tire rubber lasts about 25% longer than other road surfaces, which cuts down on maintenance costs for highways nationwide. Crumb rubber is also widely used on running tracks and playgrounds for children. It provides excellent cushioning and prevents injuries for children and adults alike. Rubber chips are also offered as mulch.
Rubber mulch is a controversial product. Some gardeners swear by it as a long lasting weed suppressant and low maintenance landscape surface. Other gardeners steer clear of rubber mulch, due to concerns about chemical leaching, fire hazards, and smell.
Here are some of the benefits of using rubber mulch instead of wood mulch:
Here are some of the problems with rubber mulch:
The jury’s still out, but recycled rubber mulch seems safe to use in certain applications. What do you think? Do you have any experience using rubber mulch in your garden or greenhouse?
Here’s another way you might want to consider to recycle old tires – they make great insulation for earth friendly homes. Crumb rubber also shows promise as a water filtering medium. In Arizona, state law makers are exploring another way to dispose of old tires: filling abandoned mine shafts to eliminate dangerous pitfalls. A few million years from now, who knows – those mine shafts might fill up with black gold!
Photo courtesy of Road Dog