The development and management of current waste tire recycling has
been examined.
In the United States, waste tire management has been successfully developed
and conducted for the last ten years. Tire stockpiles have been reduced
from 2-3 billion in 1990 to 800 million in 1996 to 500 million in 1998.
The annual waste tire recovery rate increased from approximately 17% in
1990 to 60% in 1998.
This success is primarily due to government level efforts such as law
enforcement, funding initiatives and education. However, no progress is
observed in increasing the annual recycling rate from 1996 to 1998. It
is assumed that the current waste tire management strategy has reached
its limit.
Approximately 114 million waste tires (42.2% of annual discarded tires) are converted to Tire-derived Fuel (TDF). The current high dependency on TDF conversion is one reason for the above-mentioned limitation. However, TDF is a viable solution for waste tire management from both an environmental and economic perspective. The present study also demonstrates that the development of other technologies will reduce the heavy reliance on TDF, and will stabilize the market forces for waste tire recycling. No single technology will be able to replace the entire market for TDF in the near future, however, the combination of demands from other recycling technologies has sufficient potential to provide balance. Growing markets have been observed in the application of crumb rubber (including rubber asphalt). Crumb rubber will soon occupy more than 20% of the annual waste tire recycling rate. Large scale whole tire applications such as dams and construction materials are receiving greater attention due to environmental considerations. Pyrolysis and passenger tire retreading are potential large markets in the near future, but currently no successful commercial scale examples are evident.
Economic feasibility is a primary consideration to all recycling technology.
The economic feasibility of all current technologies is based on some sort
of government support. Approximately $0.6/tire is paid for waste tire processing
from
government funding or from disposal fees paid by individual customers.
Due to this revenue, TDF, crumb rubber applications, and whole tire applications
have maintained a cost advantage compared to other alternatives, but the
margin is quite small.
The growing and potential markets of several other technologies will
certainly tend to stabilize waste tire management.