Tire Problem

Tlie Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980 was tire first major response to tire problem of abandoned hazardous waste sites throughout the nation. CERCLA was the begiiming of tlie remediation of hazardous waste sites. This program was designed to ... 

An appropriate sampling program is critical in the conduct of a hcaltli risk assessment. This topic could arguably be part of the exposure assessment, but it has been placed within hazard identification because, if the degree of contamination is small, no further work may be necessary. Not only is it important that samples be collected in a random or representative manner, but the number of samples must be sufficient to conduct a statistically valid analysis. The number needed to insure statistical validity will be dictated by the variability between the results. The larger the variance, tlic greater the number of samples needed to define tire problem, ... 

Stark, J., in The Tire Recycle Solution Minnesota s Answer to the Scrap Tire Problem, Tire Technology Conference, Clemson University, Oct. 28-29, 1987. 

Goddard, H. C. 1992. Incentives for solving the scrap tire problem through existing markets. Journal of Hazardous Materials, 29, 165-177. 

This report discusses the problems associated with scrap tires and identifies existing and potential source reduction and utilization methods that may be effective in solving the tire problem. Barriers to increased utilization and options for removing the barriers are identified and evaluated. 

Over 242 million scrap tires are generated each year in the United States. In addition, about 2 billion waste tires have accumulated in stockpiles or uncontrolled tire dumps across the country. Millions more are scattered in ravines, deserts, woods, and empty lots. Scrap tires provide breeding sites for mosquitoes which can spread diseases and large tire piles often constitute fire hazards. Most tire and solid waste professionals agree that a tire problem exists. 

Frequently, when one or two tires of a set are worn, the entire set is replaced with new tires. Useful tread may remain on several of the remaining tires. These tires are often sold for second cars or farm equipment. About 10 million tires per year are currently being reused. Although the reuse of partially-worn tires cannot be expected to solve the tire problem, reuse could potentially double based on the number of good tires currently thrown away. 

Most of the technologies available for mitigating the nation s scrap tire problem are limited by both economic and noneconomic barriers, and it is often difficult to separate the two. For example, the use of retreaded or used automobile tires is limited by competitive new tire prices, an economic barrier, as well as consumer concerns about safety and reliability, a noneconomic barrier. Designing tires to last 100,000 miles or more would cost considerably more and also would likely result in rougher rides and more tire noise. 

There is now a general public awareness throughout the U.S. that a waste tire problem exists. A number of options have been identified to address the problem, many of which are currently being utilized in several states. State, local, and federal governments need to work on the waste tire problem from all possible angles, in order to arrive at a strong solution. 

While artificial reefs do not hold the potential to solve the scrap tire problem, they do have the potential to consume more than they consume now. Currently there are an estimated 120,000 to 150,000 tires used annually in constructing reefs. The goal of Cape May and Ocean Counties is to construct reefs with about 200,000 tires annually. Currently they are doing about 60 percent of this. One estimate of national potential is between one and 1.5 million tires used yearly (16). This is much higher than current levels because only two counties are actively constructing... 

Table 13 SUMMARY OF BARRIERS TO SOLVING SCRAP TIRE PROBLEM Technology Economic Barriers Noneconomic Barriers... 

An integrated solution is needed to the waste tire problem. Both government and industry need to work together to develop markets for scrap tires and to ensure proper disposal of those tires that are not recycled and are not incinerated for their energy value. In the next two sections of this chapter, options for mitigating the scrap tire problem are discussed. 

As reported in Chapter 1, 23 states have responded to the scrap tire problem by issuing laws that specifically address this problem. An additional 13 states have regulated tires under provisions of other laws, for instance solid waste laws. As of January 1991, an additional 7 more were in the process of drafting or proposing scrap tire laws or regulations (12). 

Following are additional regulatory and non-regulatory options which have been suggested to help mitigate the scrap tire problem. Some of these have been... 

Both the Federal government and states have sponsored research. Funding levels for Federal research on the waste tire problem have fluctuated widely over the past two decades. The Department of Energy (DOE) has also researched recycling of tires, incineration and pyrolysis. Pyrolysis in particular, received significant research funding in the 1970 s, but the economics as yet have not been favorable for this technology to be commercially established in the United States. 

States and communities can work together to address tire problems. They can pool resources so that studies of the use of rubber in pavements, and studies of other uses of rubber from tires, could be performed on a larger scale leading to more useful results. 

Education and promotion is an important component of any program to alleviate the problems of waste tires. Audiences that may need to be informed about one facet or another of the scrap tire problem include individual citizens, environmental groups, tire dealers, corporations, those who are or would like to be involved in businesses related to scrap tires, potential users of scrap tire material, and representatives of local, state and Federal government. 

The book is presented in two parts. Part I covers the problems associated with scrap tires and identifies existing and potential source reduction and utilization methods that may be effective in solving the tire problem. Barriers to increased utilization and options for removing the barriers are identified and evaluated. Part II provides information on the use of whole, scrap tires and tire-derived-fuel (TDF) as combustion fuel, and on the pyrolysis of scrap tires. The use of whole tires and TDF as a primary fuel is discussed for dedicated tire-to-energy facilities. The use of whole tires and TDF as a supplemental fuel is discussed for cement manufacturing plants, electric utilities, pulp and paper mills, and other industrial processes. The focus of Part II is on the impact of burning whole tires and TDF on air emissions. The information in the book is from the following documents ... 

There are many elaborations that have been developed over the years. One of the most important is the k + 1 rule. If a vertex has remained part of the simplex for k + 1 steps, perform the experiment again. The reason for this is that response surfaces may be noisy, so an unduly optimistic response could have been obtained because of experimental error. This is especially important when the response surface is flat near the optimum. Another important issue relates to boundary conditions. Sometimes there are physical reasons why a condition cannot cross a boundary, an obvious case being a negative concentration. It is not always easy to deal with such situations, but it is possible to use step 5 rather than step 4 above under such circumstances. If the simplex constantly tries to cross a boundary either the constraints are slightly unrealistic and so should be changed, or the behaviour near tire boundary needs further investigation. Starting a new simplex near tire boundary with a small step size may solve tire problem. 

---