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MARKETS FOR SCRAP TIRES
October 1991
United States Environmental Protection Agency
Office of Solid Waste
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th Floor
Chicago, IL 60604-3590
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Disclaimer
Any mention of company or product names in the report does not constitute
endorsement by the Environmental Protection Agency.
11
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TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY 1
The Scrap Tire Problem 1
Source Reduction Alternatives 6
Recycling Alternatives 7
Tire to Energy Alternatives 8
Pyrolysis Alternatives 8
Barriers to Increased Scrap Tire Utilization 9
Options for Mitigating the Scrap Tire Problem 11
Study Conclusions 12
CHAPTER 1-ASSESSMENT OF PRESENT SITUATION 15
INTRODUCTION 15
GENERATION OF WASTE TIRES 16
ENVIRONMENTAL PROBLEMS ASSOCIATED WITH WASTE TIRE
STOCKPILES 18
Mosquitoes 18
Fire Hazards 22
SOURCE REDUCTION OF WASTE TIRES 23
Design Modifications 23
Reuse 23
Retreading 24
DISPOSAL OF WASTE TIRES 25
Whole Tire Disposal 25
Shredded Tire Disposal 25
State Legislation Affecting Tire Disposal 26
UTILIZATION ALTERNATIVES 29
Applications of Whole Waste Tires 29
a) Artificial Reefs and Breakwaters 29
b) Playground Equipment 33
c) Erosion Control 33
d) Highway Crash Barriers 33
Applications of Processed Waste Tires 34
a) Splitting/Punching of Tires 34
b) Manufacture of Crumb Rubber
from Scrap Tires 34
1) Crumb Rubber in Rubber and Plastic
Products 35
2) Crumb Rubber in Railroad Crossings 35
3) Rubber Reclaim 36
4) Crumb Rubber Additives for Pavements 37
(a) Rubber Modified Asphalt
Concrete 37
(b) Asphalt-Rubber 38
(c) Research and Demonstration
of RUMAC and Asphalt-
Rubber 40
in
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(d) Markets and Life Cycle Cost
of RUMAC and Asphalt-Rubber 41
c) Lightweight Road Construction Material 42
d) Playground Gravel Substitutes 43
e) Sludge Composting 44
Combustion 45
a) Power Plants 46
1) Modesto Power Plant 46
2) Sterling Power Plant 51
3) Erie Power Plant 51
4) Nevada Power Plant 52
b) Tire Manufacturing Plants 52
c) Cement Kilns 53
DGenstar Cement 55
2) Arizona Portland 57
3) Southwestern Portland 57
d) Pulp and Paper Production 58
1) Tire-Derived Fuel Supply 58
2) Use of Tire-Derived Fuel 58
e) Small Package Steam Generators 59
Pyrolysis 60
a) Baltimore Thermal 61
b) J.H.Beers, Inc. 61
c) TecSon Corporation 61
d) Conrad Industries 61
e) Firestone Tire & Rubber Company 62
f) The Oil Shale Corporation (TOSCO) 62
CHAPTER 2 - MARKET BARRIERS TO WASTE TIRE UTILIZATION 63
INTRODUCTION 63
RUBBER ASPHALT PAVING SYSTEMS 69
Economic Barriers 69
Noneconomic Barriers 70
COMBUSTION 71
Economic Barriers 71
a) Power Plants 71
b) Tire-Derived Fuel 73
Noneconomic Barriers 75
a) Power Plants 75
b) Tire-Derived Fuel 76
PYROLYSIS 77
CHAPTER 3 - OPTIONS FOR MITIGATING THE WASTE TIRE
PROBLEM 79
INTRODUCTION 79
REGULATORY OPTIONS-BASED ON EXISTING STATE PROGRAMS 80
Funding Sources 81
a) Taxes or Fees on Vehicle Titles or
Registration 81
b) Taxes or Fees on the Sales of New Tires
or the Disposal of Old Tires
IV
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c) Fees on the Permitting of Tire 81
Processing or Disposal Facilities,
and the Use of State Budget
Appropriations 81
Identify and Clean Up Tire Dumps 81
Methods for Managing Current Tire Disposal 82
a) Stockpile Regulations 82
b) Processor Regulations 82
c) Hauler Regulations 82
Market Development Incentives 83
a) Rebates for Tire Recycling and
Energy Uses 83
b) Grants and Loans by State Governments 84
c) Funds for Testing Innovative
Uses of Scrap Tires 85
Regulations Regarding the Landfilling of Tires 85
OTHER REGULATORY AND NON-REGULATORY OPTIONS 85
Procurement Strategies 86
Research 86
Additional Coordination Among States and Localities 87
Education and Promotion 87
Waste Exchanges 88
Tradeable Credits 89
Tax Incentives 89
CHAPTER 4 - CONCLUSIONS 91
REFERENCES 93
Appendix A-EPA REGIONAL OFFICES 99
Appendix B - STATE CONTACTS FOR WASTE TIRE PROGRAMS 101
Appendix C - ADDITIONAL SOURCES OF INFORMATION ON
SCRAP TIRES 113
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LIST OF TABLES
Table Page
1 Scrap Tire Legislation Status 4
2 Contents of Scrap Tire Legislation 5
3 Auto, Truck, and Farm Tire Shipments 17
4 Scrap Tire Generation in the United States 19
5 Material and Energy Recovery from Scrap Tires 21
6 Estimated Tire Shredding Costs 27
7 Costs of Landfilling Automotive Waste Tires
in the United States 28
8 Scrap Tire Legislation Status 30
9 Contents of Scrap Tire Legislation 31
10 Asphalt-Rubber Applicator Companies 40
11 Comparison of Rumac and Asphalt-Rubber Costs
with Standard Asphalt Costs 43
12 Summary of Measured Emissions at the Control
Device Outlet 50
13 Summary of Barriers to Solving Scrap Tire
Problem 64
VI
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LIST OF FIGURES
Figure Page
1 Flow diagram showing estimated destination of
scrap tires in 1990 3
2 Flow diagram showing estimated destination of
scrap tires in 1990 20
3 Destination of waste tires, 1990 22
4 An integrated tire utilization system 47
5 Schematic of a tire incineration project 48
6 Schematic of cement manufacturing process 54
7 Tire feed system flow sheet 56
vn
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MARKETS FOR SCRAP TIRES
EXECUTIVE SUMMARY
The management of scrap tires has become a growing problem in recent years.
Scrap tires represent one of several special wastes that are difficult for municipalities
to handle. Whole tires are difficult to landfill because they tend to float to the
surface. Stockpiles of scrap tires are located in many communities, resulting in
public health, environmental, and aesthetic problems.
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.
The Scrap Tire Problem
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.
Six facets of the tire problem are listed below:
Tires are breeding grounds for mosquitoes. Besides the major nuisance
of mosquito bites, mosquitoes can spread several serious diseases.
Uncontrolled tire dumps are unsightly and are fire hazards. Fires in
tire dumps have burned for months, creating acrid smoke and leaving
behind a hazardous oily residue. A few tire fire locations have become
Superfund sites.
Tires should be utilized to minimize environmental impact and
maximize conservation of natural resources. This means reuse or
retreading first, followed by reuse of the rubber to make rubber
products or paving, and then combustion and disposal. At present, the
preferred uses do not accommodate all the tires, and disposal must be
utilized to a large degree.
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Waste tires have to go somewhere. They tend to migrate to the least
expensive use or disposal option. As costs or difficulties of legal
disposal increase, illegal dumping may increase.
Disposing of waste tires is becoming more expensive. Over the past 20
years the average tipping fees for disposing of tires have continually
increased. This trend is likely to continue as landfill space becomes
more scarce.
Tires take up landfill space. Whole tires are banned from many
landfills or charged a higher tipping fee than other waste; even if they
are carefully buried to prevent rising they are very bulky. Shredded
tires take up less space, but it is space that could be saved if the tires
were utilized as raw material for products or as fuel.
As described above, the continuing accumulation of waste tires has led to six
concerns of varying severity. Clearly, the mosquito and fire hazard problems are the
most serious of the concerns listed. Controlling them in the near term will
necessitate providing adequate safeguards on existing stockpiles. Ultimately,
decreasing the waste tire accumulations will involve appropriate uses of recycling,
combustion, and landfilling. The current trends of reuse and source reduction
indicate that the quantity of tires utilized in products is likely to remain smaller
than the quantity combusted or landfilled in the future.
It is estimated that less than 7 percent of the 242 million tires discarded in
1990 were recycled into new products and about 11 percent were converted into
energy. Over 77 percent, or about 188 million tires per year, were landfilled,
stockpiled, or illegally dumped, and the remaining 5 percent were exported. The
flow of scrap tires is shown in Figure 1.
Scrap tire legislation is increasing rapidly at the state level. In 1990, twelve
states passed or finalized scrap tire laws, regulations, or amendments. As of January
1991, thirty-six now have scrap tire laws or regulations in effect, and all but 9 states
regulate or have bills being proposed to regulate tires. A summary of the states'
laws in effect in January 1991 are listed in Table 1. The contents of the legislations
and the sources of funding are summarized in Table 2.
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Vehicles
242
42.2
17.4%
100%
Waste Tire Inventory *
187.8
I
Illegal Dumping
12
5.0%
77.6 %
Landfill
1. Whole
2. Shredded
i
Stockpile
25.9 10.7%
0.3 I 0.1 %
Combustion
1. Power plants
2. Tire plants
3. Cement plants
4. Pulp and paper mills
5. Small package boilers
Whole Tire Applications
1. Reefs and breakwaters
2. Playground equipment
3. Erosion control
4. Highway crash barriers
16.0
6.6%
Processed Tire Products
1. Processed rubber products
2. Crumb rubber for pavements
3. Playground gravel
substitute
4. Sludge composting
5. Split tire products
Figure 1. Flow diagram showing estimated destination of scrap tires in 1990.
(In millions of tires and percent)
* Retreads (33.5 million) and reused tires (10 million) are not counted as scrap tires.
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Table 1
SCRAP TIRE LEGISLATION STATUS
January, 1991
Draft Proposed Regs Law
Alabama X
Alaska
Arizona
Arkansas X
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts X
Michigan
Minnesota
Mississippi X
Missouri
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Draft Proposed Regs Law
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota*
Tennessee
Texas
Utah
Vermont
Virginia
Washington
Wisconsin
West Virginia
Wyoming
Draft - draft being written/bill in discussion
Prop - proposed/introduced in 1990 legislature
Regs - regulated under specific provision of solid waste or other laws (e.g., automotive wastes)
Law - scrap tire law passed
X
X
X
X
X
X
X
X
X
X
X
X
Source: Scrap Tire News, Vol. 5, No. 1, January 1991
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Table 2
CONTENTS OF SCRAP TIRE LEGISLATION
Arizona
California
Colorado
Connecticut
Florida
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Michigan
Minnesota
Missouri
Nebraska
New Hampshire
North Carolina
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
Wisconsin
Funding
Source
2% sales tax on retail sale
$0.25/tire disposal fee
$1. 00/tire retail sales
$0.50/vehicle title fee
permit fees/tire storage sites
$0.50/tire retail sales
$1 .00/tire retail sales
$1. 00/tire disposal fee
state budget appropriations
$0.50 vehicle title fee
$4.00/vehicle title transfer
$0.50/tire retail sales
$1 .00/tire retail sales
graduated vehicle regist. fee
1% sales tax on new tires
$1.00/new tire (surcharge)
$1.00/new tire (dspl tax)
$0.50/new tire sales tax
graduated tax per tire size
$0.50/new tire (dspl tax)
$2. 00/tire vehicle title fee
Storage
Regs
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Processor
Regs
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Hauler Landfill Market
Regs Restrictions* Incentives
X
X
X
draft
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
R&D grants
grants/loans
grants
grants
grants/loans
grants
grants
funds/testing
grants
funds/collection
grants
$0.01 /Ib
R&D grants
$20/ton
funds/testing
grants
$20/ton
The majority of states have imposed regulations that require tires to be processed (cut, sliced, shreeded) prior to landfilling.
Some of the states allow for storage (above ground) of shreds at landfills. OH, NC, CO are among the states considering or allowing
monofils for tire shreds. Whole tires are discoraged from landfills (in almost all cases) either by law (e.g., MN) or more
frequently by high disposal fees.
Source: Scrap Tire News, Vol. 5, No. 1, January 1991.
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Source Reduction Alternatives
Source reduction measures for tires include the following:
Design of extended life tires
Reuse of used tires
Retreading
Great strides have been made in the last 40 years in tire manufacturing that have
more than doubled the useful life of tires. Forty thousand mile tires are common-
place, and 60,000 to 80,000 mile lifetimes are often achieved. Constraints of cost, fuel
consumption, and comfortable rides, make it unlikely that any major design
changes will occur in the near future that will significantly increase lire life.
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.
Retreading is the application of a new tread to a worn tire that still has a good
casing. There are currently over 1,900 retreaders in the United States and Canada;
however, that number is shrinking because of the decreased markets for passenger
retreads. This decline is primarily due to the low price of new tires and the
common misperception that retreads are unsafe. The price of inexpensive new
passenger tires ($50 to $60) is often at or near the price of quality retreads. On the
other hand, truck tire retreading is increasing. Truck tires are often retreaded three
times before being discarded and the truck tire retreading business is increasing.
The National Tire Dealers and Retreaders Association asserts that properly-
inspected retreaded tires have lifetimes and failure rates comparable to new tires.
Mileage guarantees and/or warranties for retreads are often similar to or identical to
new tire warranties. In 1987, about 23 million passenger and light truck tires and 14
million truck tires were retreaded. By 1990 these retread rates changed to 18.6
million and 14.9 million, respectively. It is estimated that most good truck tire
casings are being retreaded due to the high cost of new truck tires, but that at least
two times as many passenger and light truck tires would be suitable for retreading.
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Recycling Alternatives
Some recycling alternatives use whole tires, thus requiring no extensive
processing; other alternatives require that tires be split or punched to make
products; and still other alternatives involve tires that are finely ground enabling
the manufacture of crumb rubber products. Some applications for each alternative
are listed below:
Whole tire applications
Artificial reefs and breakwaters
Playground equipment
Erosion control
Highway crash barriers
Split or punched tire applications
Floor mats, belts, gaskets, shoe soles, dock bumpers, seals, muffler
hangers, shims, washers, and insulators
Shredded tire applications
Lightweight road construction material
Playground gravel substitutes
Sludge composting
Ground rubber applications
Rubber and plastic products; for example, molded floor mats,
mud guards, carpet padding, and plastic adhesives
Rubber railroad crossings
Additives for asphalt pavements
All of the tire recycling alternatives listed above are being used to varying
degrees. However, the total usage of tires for recycling currently is estimated to be
less than 7 percent of the annual generation. The markets for most of the products
may be increased, but, even if increased to their fullest potential, appear to be small
compared to the number of tires generated each year. Ground rubber applications
hold the greatest promise. The tire recycling alternative with the greatest potential
to significantly reduce the scrap tire problem of the United States is in asphalt
highway construction.
There are two types of processes for using crumb rubber in pavements. One
application, referred to as rubber modified asphalt concrete (RUMAC), involves
replacing some of the aggregate in the asphalt mixture with ground tires. The
second, called asphalt-rubber, blends/reactivates a certain percentage of the asphalt
cement with ground rubber. Both systems are being evaluated by state agencies as
well as the federal government.
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Tire to Energy Alternatives
Tires have a fuel value of 12,000 to 16,000 Btu per pound, slightly higher than
that of coal. With existing technology, tire combustion can meet Federal and State
environmental requirements. Tires may be burned whole or shredded into tire
derived fuel (tdf)- Whole tire combustion requires less processing expense;
however, most of the plants currently burning tires for fuel do not have the
capability to burn whole tires. In 1990, about 25.9 million tires (10.7 percent of total
generation) were burned for energy production. Combustion facilities currently
using tires as fuel include:
Power plants
Tire manufacturing plants
Cement kilns
Pulp and paper plants
Small package steam generators
The largest scrap tires combustion system is the Oxford Energy plant in
Modesto, California. It consumes about 4.9 million tires per year and generates 14
MW of power. A second Oxford Energy power plant, designed to burn about 9-10
million tires per year, is under construction in Connecticut. Commercial operation
is planned for 1991.
Seven cement kilns in the United States utilize about 6 million scrap tires per
year to replace conventional fuels. Cement kilns appear to be ideal for scrap tires
because of their high operating temperatures (2,600 F) and good conditions for
complete combustion, which minimize air pollution problems. Also, there is no
residue, since the ash is incorporated into the cement product. Of the 240 cement
kilns in the United States, about 50 are equipped with precalciner/preheaters,
making them most suitable for tire combustion.
Many furnaces designed to burn wood chips at pulp and paper plants are
suitable for burning tire-derived-fuel without major modifications. Frequently,
only wire-free tdf can be used in these boilers, thus increasing the tire processing
costs. An estimated 12 million tires per year are currently being consumed by the
pulp and paper industry.
Pyrolysis Alternatives
Pyrolysis of tires involves the application of heat to produce chemical changes
and derive various products such as carbon black. Although several experimental
pyrolysis units have been tried, none has yet demonstrated sustained commercial
operation.
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Barriers to Increased Scrap Tire Utilization
Barriers to increased scrap tire utilization can be classified into two main
types - economic and noneconomic.
Economic barriers refer to the high costs or limited
revenues associated with various waste tire utilization
methods which make the uses unprofitable. Tire
processors will not invest time or capital unless there is a sufficient
rate of return to justify the efforts.
Noneconomic barriers refer to a number of constraints on utilization.
These include technical concerns such as lack of technical information
or concerns regarding the quality of products or processes. These
barriers also include the reluctance of consumers, processors, and
regulators to employ new approaches or technologies for aesthetic or
other reasons. They also include constraints on utilization because of
health and safety, environmental issues, laws, and regulations.
The strength and persistence of these barriers are evident from the
continuing buildup of tire stockpiles and dumps over the last several years.
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.
Making products such as reefs, playground equipment, floor mats, gaskets,
etc., out of scrap whole or processed scrap tires is primarily limited by the high cost
of tires compared with other raw materials. However, there are also some
noneconomic barriers. Reefs made of tires, for example, are not appropriate for the
rough shores of the northwest. Playground equipment made of wood or other
products is often preferred for aesthetic reasons.
The two technologies with the most potential for using a major portion of
scrap tires generated each year, and actually reducing the tire stockpiles, are
pavements with rubber additives and combustion for energy generation.
Barriers to the increased usage of rubber in asphalt pavements are both
economic and noneconomic in nature. The cost of installing roads of rubberized
asphalt is greater than conventional asphalt, which is an economic barrier. On the
other hand, several studies show that the total life cycle cost of rubberized asphalt is
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lower than conventional asphalt. This would be an economic benefit. However,
decisions on paving are often made on the basis of road miles paved per year, rather
than life cycle cost of the pavement.
The two forms of rubberized asphalt that have been tested the longest,
asphalt-rubber and PlusRide, are patented. The required royalty fees increase the
cost of these products. Although, initially, patents may have stimulated the growth
of these products, they now appear to represent an economic barrier to increased
scrap tire usage by these technologies. The patent for asphalt-rubber expires in 1991.
After that more companies are expected to become involved, resulting in lower
costs. Non-patented rubberized asphalt roadways are also being tested.
One of the major noneconomic barriers to the use of rubber in asphalt
pavements has been the lack of consensus on the results of long-term testing. Many
long-term tests have been performed, but they were performed in over a dozen
states, and as yet these tests have not been brought together and evaluated in a
cohesive study.
Power plants to burn scrap tires involve large capital investments and annual
operating expenses. However, plants located near large supplies of tires can be
feasible. A key variable in determining economic feasibility for these plants is the
buy-back rate granted by the utility. In areas of the country where the rate is high,
such as California and the northeast, power plants are feasible. The buy-back rate is
the rate the utilities pay for electricity generated from alternative fuel,, and reflects
the fuel and other costs avoided by the utility.
Burning tires in existing pulp and paper mills and certain types of cement
kilns requires much less capital investment than the dedicated power plants
mentioned above. Pulp and paper mills often burn hog-fuel (chipped wood), thus
requiring very little modification for tire chips. The main economic variable is the
price of the competing fuel. Tire-derived fuel must often compete with low cost
coal or petroleum coke, a waste product from the petroleum refining process. If tdf
is only slightly cheaper than the alternate fuel, then plant modification cannot be
justified.
The main noneconomic barriers to scrap tire combustion are the time
required for permitting a plant and the concerns of neighbors regarding
environmental, health, and safety issues. Because of the test burns required and
time delays in permitting, many cement plant and pulp and paper mill operators
hesitate to change their operation for the small savings realized by burning scrap
tires.
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Options for Mitigating the Scrap Tire Problem
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.
State governments have been very active in utilizing a variety of techniques
for addressing tire problems. By the end of 1990, thirty-six states had regulated scrap
tires, up from only one state in 1985. Twenty-one states had funded their state tire
management programs through such means as a tax or surcharge on tires, added
vehicle registration fees, or fees to transfer vehicle titles. Twenty-four states had
final regulations addressing storage of tires. At least twelve states had included
some type of market incentives such as rebates, grants or loans to help build markets
for scrap tires.
These state laws can make a significant dent in solving the nation's tire
problem. Particularly important provisions are funding sources based on taxes or
fees on tires sold or on vehicles sold or transferred; mandates to clean up of tire
dumps; regulations to reduce fire and mosquito hazards at tire stockpiles; and
recordkeeping and tracking requirements to ensure that tires are sent only to
reputable haulers, processors, or end-users who manage the tires legally. Market
incentives such as the rebate systems instituted by the states of Oregon, Wisconsin,
Utah, and Oklahoma, have been very successful in promoting additional recycling
and the use of tires for energy recovery.
In addition to the state regulations, other ideas that have been implemented
or proposed to address scrap tires, include: (1) procurement strategies; (2) research;
(3) increased coordination among states; (4) education and promotion; (5) waste
exchanges; (6) tradeable credits; and (7) tax incentives.
EPA's Federal procurement guidelines for retreaded tires, which became
effective on November 17, 1989, are encouraging Federal agencies both to retread
tires on their vehicles, and to buy retreaded tires. States may decide to develop
similar guidelines to encourage retreaded tires.
There is a need to continue to perform research on methods of recycling tires,
such as the use of crumb rubber in rubber products and plastics. Existing research on
rubberized asphalt should be summarized, and a decision made regarding its
feasibility for more widespread use, or if there are still technical or economic
questions, determining exactly what additional research is needed to answer these
questions, and then perform this research. States and Federal government, and
environmental and transportation agencies, should coordinate research efforts so
that fewer, more comprehensive research projects (particularly related to rubberized
asphalt) can be performed.
11
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Other means of exchanging information such as conferences on scrap tires,
hotlines, newletters, waste exchanges, and computerized data bases, are being
developed or utilized by both government and industry. Because the economics
and technology of scrap tires is changing so rapidly, these sources are particularly
helpful in spreading information regarding scrap tires, to government officials,
entrepreneurs, environmental groups, and private citizens.
Study Conclusions
Each year about 242 million tires are scrapped. Current trends indicate that
less than 7 percent of these tires are being recycled as products and 11 percent are
being burned for energy, and 5 percent are being exported. The rest are being
landfilled, stockpiled, or dumped illegally.
EPA wishes to encourage waste tire reduction and recycling, with a special
emphasis on reducing the number of tires in uncontrolled stockpiles or illegal
dumps. These tires are often sites of mosquito infestation, with the potential for
spreading dangerous mosquito-borne diseases. Large tire dumps can also lead to
fires with major releases of hazardous organic chemicals into the air, surface water,
and ground water.
Recycling rubber from tires for use in asphalt pavements is a promising
technology. Asphalt pavements incorporating tire rubber are claimed to have twice
the lifetime of ordinary asphalt, but they can cost twice as much. Pavements with
crumb rubber additives consume over one million tires per year now, and both
asphalt-rubber and rubber modified asphalt concrete have considerable potential for
expansion. If Federal, state, and local governments promote much broader use and
demonstration of this technology, perhaps the technical issues will be resolved and
usage will expand.
Using whole tires as fuel for reciprocating grate power plants ap>pears to be
economically feasible in some regions of the country, and can meet environmental
permitting requirements. One such plant in Modesto, California, is currently
consuming 4.9 million tires per year. Another power plant is under construction in
Connecticut and is expected to consume an additional 10 million tires per year. A
second 10 million tire per year plant is being planned for an area near Las Vegas,
Nevada. The main barriers to such plants appear to be local resistance? to
incineration projects and lengthy permitting procedures.
The replacement of coal by tire-derived-fuel appears economically feasible for
cement kilns. Seven such kilns are currently operating in the U.S., consuming the
equivalent of about 6 million tires per year between them. There is potential for
this use to expand further, particularly for those cement kilns whose feed systems
are compatible with the use of TDF.
12
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Tire-derived fuel is economically feasible for use in hog fuel boilers in the
pulp and paper industry. It is estimated that the equivalent of 12 million tires is
consumed annually in this way in the U.S. There is potential for this use to expand
further.
Other technologies and options are promising on a smaller scale, but also are
important to the overall solution. Uses of crumb rubber for such diverse products
as athletic surfaces, tracks, and rubber molded products, show potential for growth.
Also, increased retreading could utilize a significant number of tires. If the market
justified retreading all the usable carcasses, about 20 million additional passenger
and light truck tires could be retreaded each year. Current trends, however, indicate
that fewer of these tires are retreaded each year.
Other uses of tires are sometimes feasible for specialized geographic
conditions. Cape May County, New Jersey uses 100,000 tires per year, which is 100
percent of its scrap tires, for artificial reefs. The State of Minnesota has used about a
million of its tires since 1986 for roads in swampy areas.
The markets for most other products made from tires have potential, but
appear to be relatively small. These include rubber railroad crossings, artificial reefs,
playground equipment, erosion control, highway crash barriers, playground gravel
substitute, sludge composting, rubber farm and agricultural equipment, and rubber
mats. Each of these products has the potential for using some portion of our waste
tire stockpile. Collectively, they are all important parts of the solution to the tire
problem.
13
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Chapter 1
ASSESSMENT OF PRESENT SITUATION
INTRODUCTION
About 242 million automotive, truck, and off-road tires are discarded in the
United States each year. This is approximately equal to one waste tire per person per
year. Additionally, there are 33.5 million tires that are retreaded and an estimated 10
million that are reused each year as second-hand tires. It is estimated that 7 percent
of the discarded tires are currently being recycled into new products and 11 percent
are converted to energy. Nearly 78 percent are being landfilled, stockpiled, or
illegally dumped, with the remainder being exported.
Tires are difficult to landfill. Whole tires do not compact well, and they tend
to work their way up through the soil to the top. As a result, tire stockpiles, which
cost less than landfills, have sprung up all over the country. It is estimated that
between 2 and 3 billion tires are stockpiled in the U.S. at present, with at least one
pile containing over 30 million tires. Tire stockpiles are unsightly and are a threat
to public health and safety. Not only are tire piles excellent breeding grounds for
mosquitoes, but they are also fire hazards.
It is the goal of the EPA to eliminate illegal dumping altogether and to reduce
the stockpiling and landfilling of discarded tires as much as possible. The report,
The Solid Waste Dilemma: An Agenda for Action, lays out EPA's national strategy
for managing municipal solid waste (MSW) (1). It sets out a three-tier hierarchy for
management of municipal solid waste, with source reduction ranking first, followed
by recycling, then incineration and land disposal. Interestingly enough, over the last
40 years, tires have been somewhat of a success story for source reduction. The
advent of the 40,000-mile tire means that tires last longer before they wear out.
As with many other components of the waste stream, the highest priority
options, source reduction and recycling, are the least utilized and landfilling is the
most common practice. Potential source reduction measures for tires include the
design of longer lived tires, reuse of tires removed from vehicles, and retreading.
These practices all extend the useful life of tires before they are discarded.
Considerable increases in tire lifetimes have been achieved in the past 20 years with
the advent of the radial tire. On the other hand, partially because of the radial tires,
retreading of automobile tires is decreasing each year. Radial tire side walls tend to
be weaker than bias ply walls, thus the rejection rate by retreaders is higher. Radials
also are more expensive to retread than bias plies. Truck tire retreading, however, is
still increasing. A total of about 37 million tires were retreaded in 1987. This
dropped to 33.5 million in 1990. Retreading extends the useful life of a retreadable
15
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tire from 60 to 80 percent (an automobile tire with one retread) to 300 percent (a
truck tire with three retreads).
Tire recycling activities include the use of whole tires or processed tires for
useful purposes. Whole tire applications include reefs and breakwaters, playground
equipment, erosion control, and highway crash barriers. Processed tire products
include mats and other rubber products, rubberized asphalt, playground gravel
substitute, and bulking agent for sludge composting.
Scrap tire combustion is practiced in power plants, tire manufacturing plants,
cement kilns, pulp and paper plants, and small package steam plants.
GENERATION OF WASTE TIRES
It is commonly accepted in the tire industry that about one tire per person per
year is discarded. Since there is no industry group or governmental agency that
monitors tire disposal in the United States, the best estimates that can be made are
based on tire production. The Rubber Manufacturers Association (RMA) records the
number of original equipment, replacement, and export tires that are shipped each
year in the United States. (See Table 3.) In 1990, a total of 264,262,000 tires were
shipped. The RMA data include new tire imports, but not imported used tires. To
estimate the number of tires that were discarded in the United States in 1990, the
following assumptions were made:
One tire is discarded for each replacement tire
shipped, including new and used imports. (Discard is
assumed to be in the same year as replacement tire
production.)
Original equipment tires are not discarded in
the year they are produced, but rather in the
year a replacement is sold.
Exported tires are not discarded in the USA.
Four tires are discarded for each automobile or
truck when it is taken out of service.
Retreads and reused tires are put back into
service in the same calendar year that they were
taken out. (Therefore, retreading and reuse simply
have the effect of extending the tire's useful life.)
16
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Table 3
U.S. AUTO, TRUCK, AND FARM TIRE SHIPMENTS*
(In thousands of tires)
1990
Original equipment
Replacement
Export
Totals
1989
Original equipment
Replacement
Export
Totals
1988
Original equipment
Replacement
Export
Totals
1987
Original equipment
Replacement
Export
Totals
1986
Original equipment
Replacement
Export
Totals
Passenger
47,199
152,251
14,110
213,560
51,170
151,156
12,437
214,763
54,131
155,294
9,365
218,790
52,913
151,892
5,987
210,792
54,392
144,267
4,032
202,691
Farm
s/Truck Equipment
6,993
36,588
3,283
46,864
8,177
35,172
3,548
46,897
8,801
33,918
3,301
46,020
7,845
34,514
2,069
44,428
6,859
32,392
1,302
40,553
995
2,549
294
3,838
890
2,664
270
3,824
753
2,662
267
3,682
608
2,658
226
3,492
512
2,319
170
3,001
Total
55,187
191,388
17,687
264,262
60,237
188,992
16,255
265,484
63,685
191,874
12,933
268,492
61,366
189,064
8,282
258,712
61,763
178,978
5,504
246,245
* Includes imported new original equipment and replacement tires.
Source: Rubber Manufacturers Association (RMA) Monthly Tire Report,
December 1990 and earlier years.
17
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Although these are simplifying assumptions, they lead to a good
approximation of the number of tires available for discard each year. Inaccuracies
may result because sometimes when vehicles are de-licensed, they may remain in
the junk yard or in a garage for a while before their tires are discarded. Also, when a
tire is removed from a vehicle for retreading or reuse, a new replacement tire may
take its place. For this replacement tire, there will be no corresponding discard.
However, when the retreaded tire is sold again, a waste tire would be generated.
Table 4 summarizes waste tire generation based on the assumptions above.
These data show that in 1990 scrap tires were generated at the rate of about 0.97 tires
per person per year. Figure 2 and Table 5 show the estimated disposition of the 242
million scrap tires generated in 1990. About 16.3 million were recycled, 26 million
were recovered for energy, and about 12 million were exported, leaving 188 million
for landfilling, stockpiling, or illegal dumping. Figure 3 shows that in 1990 17.4
percent of the tires scrapped were recycled or burned for energy.
ENVIRONMENTAL PROBLEMS ASSOCIATED WITH WASTE TIRE STOCKPILES
Because of the difficulty of landfilling scrap tires and the resulting high costs,
stockpiles have sprung up across the country. It is estimated that between 2 and 3
billion tires are stockpiled in the U.S. at present, with at least one pile containing
over 30 million tires. In addition to being unsightly, tire piles are excellent breeding
grounds for mosquitoes and they are fire hazards.
Mosquitoes
Mosquitoes have long been identified as pests and vectors of disease. It has
also been known for some time that tires have the potential to serve as ideal
breeding grounds for mosquitoes, especially when tires occur in large numbers in
stockpiles. Because of the shape and impermeability of tires, they may hold water
for long periods of time providing sites for mosquito larvae development.
Because tires can hold water, they have contributed to the introduction of
non-native mosquito species when used tires are imported to the U.S. The new
species are often more difficult to control and spread more disease (2).
There is evidence of tires contributing to the presence of mosquito-
transmitted diseases. The main solution that has been offered is tire shredding.
This guarantees that no water will be held for breeding sites. Further preventive
measures could include requiring all shipped tires and all stockpiles to be fumigated.
Other solutions sometimes suggested to the mosquito problem in tire stockpiles
18
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Table 4
SCRAP TIRE GENERATION IN THE UNITED STATES
(In Thousands)
Year
Replacement Tire Shipments
Passenger1/
Truck1/
Farm Equipment 1/
Imported Used Tires 27
Total Replacement Tires
Tires from Scrapped Vehicles 3/
Cars
Trucks
Total Tires from Scrapped Vehicles
Total Scrap Tires in U.S.
U.S. Population (thousands) 3/
Scrap Tires/Person/Year
1984
144,580
31,707
2,592
1,793
180.672
26.700
6.408
33,108
213,780
235,961
0.91
1985
141,455
32,098
2,395
3,233
179,181
30,916
8,400
39,316
218.497
238,207
0.92
1986
144,267
32,392
2,319
2,552
181,530
33,768
9,236
43,004
224,534
240.523
0.93
1987
151,892
34,514
2,658
2,925
191,989
32,412
9,456
41,868
233,857
242,825
0.96
1988
155,294
33,918
2,662
1,352
193,226
35.016
9,004
44,020
237,246
245,807
0.97
1989
151,156
35.172
2,664
1.466
190.458
37,200 4/
10.400 41
47,600
238.058
247,732
0.96
1990
152,251
36,588
2,549
1,108
192,496
39,000 4/
11,00047
50,000
242.496
249,981
0.97
1/ (Includes imported new tires) National Petroleum News, Fact Book, 1986-1988. Data from the Rubber Manufacturers
Association. 1988 through 1990 data from RMA Industry Monthly Tire Report, December 1989 and December 1990.
21 U.S. Department of Commerce. "U.S. Imports for Consumption." (FT246). 1984-1990.
3/ U.S. Department of Commerce. Statistical Abstracts, 1990 and prior years. Estimate based on 4 tires per vehicle.
4/ Estimated by Franklin Associates, by linear extrapolation.
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Reuse
10
10
Vehicles
242
42.2
17.4%
33.5
33.5
Retread
100%
Waste Tire Inventory *
187.8
Illegal Dumping
25.9 10.7%
Combustion
1. Power plants
2. Tire plants
3. Cement plants
4. Pulp and paper mills
5. Small package boilers
12
5.0%
77.6%
Landfill
1. Whole
2. Shredded
i
Stockpile
0.3
0.1%
Whole Tire Applications
1. Reef sand breakwaters
2. Playground equipment
3. Erosion control
4. Highway crash barriers
16.0
6.6%
Processed Tire Products
1. Processed rubber products
2. Crumb rubber for pavements
3. Playground gravel
substitute
4. Sludge composting
5. Split tire products
Figure 2. Flow diagram showing estimated destination of scrap tires in 1990.
(In millions of tires and percent)
* Retreads (33.5 million) and reused tires (10 million) are not counted as scrap tires.
20
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Table 5
MATERIAL AND ENERGY RECOVERY FROM SCRAP TIRES
No. of Tires Percentage of 242
Method of Recovery (In millions) Million Scrap Tires
Energy/Burning 25.9 10.7
Reclaim 2.9 1.2
Splitting 2.5 1.0
Crumb Rubber for Pavements 2.0 0.8
Other Crumb 8.6 3.6
Whole Tires 0.3 0.1
Total Recovered 42.2 17.4
Used Export 12 5.0
Landfill, Stockpile and 188 77.6
Dumping
Total Scrap Tires* 242 100.0
* Retreads (33.5 million) and reused tires (10 million) are not
counted as scrap tires.
Source: Franklin Associates, Ltd. and Dr. Robert Hershey. Estimates
based on published data and technical discussions.
21
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Used Export
5.0%
Other Recovery
6.7%
Energy/Burning
10.7%
Landfill/Stockpile
Illegal Dumping
77.6%
Figure 3: Destination of Waste Tires, 1990
Sources: Table 5
are to drill holes in the tires so that the water drains or to remove the tire bead and
turn the carcass inside out. This has been practiced on a small scale by individuals
(3). y
Fire Hazards
For as long as it has been known that waste tires harbor mosquitoes, it has
been known they pose a fire hazard. Tire fires are particularly bad because of the
difficulty in extinguishing them. This is because of the 75 percent void space present
in a whole waste tire, which makes it difficult to either quench the fire with water or
cut off the oxygen supply. Water on tire fires often increases the production of
pyrolytic oil and provides a mode of transportation to carry the oils off-site and
speed up contamination of soils and water.
The potential fire hazard presented by waste tire stockpiles has been realized a
number of times in the past decade. Several stockpiles have burned until their tire
supplies were exhausted which, depending on weather conditions, may be a few
days to more than a year. Air pollutants from tire fires include dense black smoke
which impairs visibility and soils painted surfaces. Toxic gas emissions include
polyaromatic hydrocarbons (PAHs), CO, SO2, NO2, and HC1. Following tire pile fires,
oils, soot, and other materials are left on site. These tire fire by-products, besides
being unsightly, may cause contamination to surface and subsurface water as
22
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well as the soils on which the tires were located. For these reasons, multimillion
dollar cleanups are sometimes required to avoid further environmental problems
(2).
If stockpiles for waste tires are carefully monitored, the fire hazard can be
reduced. Shredded tires pose less of a threat for fires. Tire shreds behave differently
than whole tires when burning and because they have less air space, they can be
extinguished more easily by allowing water to smother the fire (4). Other
precautions that may reduce the fire hazards of tire stockpiles are mandatory fire
lanes and fire plans so that a fire can be attended to as quickly as possible (3).
Ultimately, the best solution to the problems of waste tires as fire hazards and
mosquito breeding grounds is to eliminate stockpiles. At the least, the number of
tires in a stockpile should be minimized, thus reducing the number of breeding sites
for mosquitos and fuel for fires.
SOURCE REDUCTION OF WASTE TIRES
There are two options for reducing the number of tires landfilled, stockpiled,
and dumped. One is to increase recovery, which is discussed later in this report, and
the other is to reduce the number of tires generated in the first place (source
reduction). Source reduction measures that have limited potential for reducing the
number of tires to be disposed include:
Design of extended life tires
Reuse of used tires
Retreading.
Design Modifications
Great strides have been made in the last 40 years in tire manufacturing that
have more than doubled the useful life of tires. Further increases in life would
require higher pressure, thicker treads, or less flexible materials. Each of these
methods would result in more gas consumption, higher cost, and/or rougher rides.
Currently steel-belted radial passenger tires last about 40,000 miles. If these tires are
properly inflated, rotated, and otherwise cared for, 60,000 to 80,000 mile lifetimes
may be achieved. It is not expected that any major design changes will occur in the
near future that will significantly increase tire life (5).
Reuse
Frequently, when one or two tires of a set are worn, the entire set is replaced
with new tires. Useful tread may remain on one, two, or three of the tires removed.
Many tire stores and tire haulers sort out the usable tires for resale. Virtually every
major city in the USA has stores that sell used tires. These tires are often sold for
second cars or farm equipment.
23
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Although the reuse of partially-worn tires cannot be expected to solve the
scrap tire problem in the USA, it has been estimated that a minimum of one
additional year of tire life can be achieved out of 25 percent of the tires removed
from vehicles (6). Assuming this to be the case, then the reduction of the scrap tire
problem by the reuse of used tires can be estimated. Suppose a set of four tires is
removed after 40,000 miles. If 25 percent (one tire), on average still has a useful
tread of 10,000 miles left, this is equivalent to the set of four tires lasting 42,500 miles
instead of 40,000, an increase in life of 6 percent. It is not known how many good
used tires are currently being reused, but based on contacts with several tire stores, it
is evident that a significant portion (estimated 50 percent) of the good used tires are
currently being reused. If the other 50 percent were also used, a 3 percent reduction
in tire disposal could be realized.
Retreading
The third source reduction measure which can extend the useful tire life, and
therefore reduce the number of tires scrapped, is retreading. Retreading is the
application of a new tread to a worn tire that still has a good casing. Retreading
began in the 1910s and has always played a role in the replacement tire market.
There are currently over 1,900 retreaders in the United States and Canada; however,
that number is shrinking because of the decreased markets for passenger retreads.
Truck tires are often retreaded three times before being discarded and the truck tire
retreading business is increasing. On the other hand, passenger tire retreading is
declining. This decline is primarily due to the low price of new tires and the
common perception that retreads are unsafe. The price of inexpensive new
passenger tires ($50 to $60) is often at or near the price of quality retreads.
The National Tire Dealers and Retreaders Association claims that properly-
inspected retreaded tires have lifetimes and failure rates comparable to new tires.
Mileage guarantees and/or warranties for retreads are often similar to or identical to
new tire warranties.
In 1987, about 23 million passenger and light truck tires and 14 million truck
tires were retreaded. By 1990, the passenger and light truck retreads dropped to 18.6
million while truck retreads increased to 14.9 million (7). It is estimated that most
good truck tire casings are being retreaded due to the high cost of new truck tires, but
that at least twice as many passenger car and light truck tires would be suitable for
retreading. While retreading will not by itself solve the nation's tire problem,
growth in retreading would reduce the number of new replacement tires needed
each year and, therefore, reduce the number requiring disposal. For1 example, if the
markets could be developed so that all the passenger and light truck tires suitable for
retreading were actually retreaded, then about 20 million fewer new replacement
tires would be needed annually. This would reduce the number of waste tires
generated per year by almost 10 percent.
24
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DISPOSAL OF WASTE TIRES
The removal of waste tires from the generator's property is generally
performed by a tire jockey or solid waste hauler. Some hauling is done by tire users,
tire dealers, or retreaders, but the majority of the over 193 million tires that go to
dumps or stockpiles go by way of a hauler who is paid to remove waste tires from
the dealer's property. The hauler may be held accountable for the number of tires
and how they were disposed of, depending on the state. Haulers may be paid $0.35
to $5.00 per tire to dispose of the tires. If they then dispose of the tires legally, they
must pay a fee at a landfill or processing facility. If they stockpile the tires or illegally
dump them, the tires create serious health hazards.
Whole Tire Disposal
There are no known whole tire disposal methods without adverse effects.
Disposing of the tires above ground creates the hazards of mosquitoes and fires. The
alternate disposal method is landfilling or burial, which is also not without
problems. In landfills, tires require a large volume because about 75 percent of the
space a tire occupies is void. This void space provides potential sites for gas
collection or the harboring of rodents. Some landfill operators report that tires tend
to float or rise in a landfill and come to the surface, piercing the landfill cover.
The primary advantage to whole tire disposal is that processing costs are
avoided. However, landfills' bad experience with whole scrap tires has led to
extremely high tipping fees or total bans on whole tires. Landfill fees for small
quantities range from $2.00 per passenger tire to $5.00 per truck tire. For mass
quantities, tipping fees range from $35.00 per ton to over $100 per ton for whole
tires, depending on the region of the country. These fees are generally at least twice
the fee for mixed municipal solid waste.
Shredded Tire Disposal
Shredding or splitting of tires is becoming increasingly common as part of the
disposal process. Shredded tires stored above ground pose less of a hazard than do
whole tires. Shredding eliminates the buoyancy problem and makes tires into a
material that can be easily landfilled. Shredding can reduce a tire's volume up to 75
percent. This volume reduction can also reduce transportation costs 30 to 60 percent
simply because fewer trips are required and maximum hauling weights may be
achieved more easily.
Haul costs depend on many factors, including truck size, distance hauled,
local labor rates, etc. For semi-truck loads of 1,000 whole auto tires hauled over 100
miles, typical costs are in the 15 to 20 cents per ton-mile range. This is equivalent to
15 to 20 cents per 100 tires per mile. Shredding can reduce this cost by 30 to 60
percent.
25
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The main disadvantage of shredding before landfilling is that an extra
processing step is required, which adds costs. Shredder companies charge from $19
to $75 per ton to shred scrap tires (8). T.Y.R.E.S., Inc. of the Los Angeles area is
currently shredding for $18.50 a ton. But they say these costs will soon increase
significantly because of labor and liability insurance that is required by the city. They
said that about 20 tons per hour need to be processed to make the shredding
profitable. They have a mobile operation and must transport the machine from
landfill to landfill (9). Saturn Shredders, maker of mobile shredding equipment, has
broken down typical costs of a 500 to 800 tires per hour shredding operation. These
are the cost per tire to the shredder company and do not include any profit or fees.
The cost breakdown is outlined in Table 6. For the two processing rates, the cost per
tire for coarse shredding (4- to 8-inch) ranges from 18 to 25 cents per tire, or 18 to 25
dollars per ton, assuming passenger tires at 20 pounds per tire.
Shredding costs are fairly constant nationally except for labor and fuel, which
may change the total cost up or down 10 percent. When shredding costs are added
to solid waste disposal fees, it reflects the cost of landfilling shredded waste tires. For
comparison, several examples of tipping fees for whole waste tires in mass
quantities were obtained representing the northeast, midwest, south, and west
region. These values were not regional averages, but are thought to be values that
are representative of the areas.
Table 7 compares the cost of landfilling whole tires and shredded tires in the
United States. Shown are estimates of the money saved or lost by shredding prior to
landfilling. In the northeast region of the United States, where landfill costs are
highest, $38.00 per ton can sometimes be saved by shredding tires before landfilling
them. In other areas of the country, disposal costs may increase by as much as $3.00
per ton by shredding before landfilling. These cost estimates are generalizations,
and each community would need to determine if shredding before landfilling is
economical. It becomes apparent through these comparisons that as landfill space is
used up, shredding will become more beneficial, not only in terms of reducing
hazards, but also in terms of saving money.
State Legislation Affecting Tire Disposal
Scrap tire legislation is increasing rapidly at the state level. In 1990, twelve
states passed or finalized scrap tire laws, regulations, or amendments (12). Thirty-six
states now have scrap tire laws or regulations in effect, and all but 9 states regulate or
have bills proposed or in draft form to regulate tires. A summary of the states' laws
in effect in January 1991 is provided in Table 8. The legislations' contents are
summarized in Table 9.
Several states have considered or are considering legislation that would ban
all whole tires from landfills. Minnesota has already banned all tires from landfills.
In some other states, landfills have such high tipping fees that whole tires are
26
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Table 6
ESTIMATED TIRE SHREDDING COSTS
Mobile Shredders
(In dollars and cents per tire)
800 500
Tlres/nr(l) Tlres/hr(l)
CAPITAL COSTS
Shredder 155,000 155,000
Shredder Stand 48,000 48,000
Diesel Generator 30,000 30,000
Infeed Conveyor 15,200 15,200
Discharge Conveyor 16.800 16,800
Total Capital Cost (2) 265,000 265,000
ANNUAL COSTS
Debt Financing (3) 43,128 43,128
Operating & Maintenance
Labor (3 at $10/hr) 62,400 62,400
Maintenance & Supplies 8,100 5,063
Cutter replacement and sharpening 54,800 33,800
Electricity @ 8 cents/kw-hr 25,000 16,000
Overhead, Administrative,insurance 30,000 30,000
TotalO&M 180,300 147,263
Total Annual Cost 223,428 190,390
Tires Processed Per Year (25% downtime) 1,248,000 780,000
Shredding Cost (cents/tire) 17.9 24.4
(1) Capacity for passenger tires.
(2) Tractor for moving from location to location not included.
(3) Financing Assumptions:
10 percent Interest
1 0 year amortization
Source: Franklin Associates, Ltd; based on estimates supplied by Saturn Shredders.
27
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Table 7
COSTS OF LANDFILLING AUTOMOTIVE WASTE TIRES IN THE UNITED STATES
(In dollars per ton or cents per tire) 1/
Costs by Region
Shredded
Landfill Fee 21
Processing Cost
Total
Whole
Landfill Fee 3/
Processing Cost
Total
Savings Realized
by Shredding 4/
Northeast
45
25
70
108
0
108
Midwest
18
25
43
75
0
75
South
16
25
41
50
0
50
West
13
25
38
35
0
35
38
32
-3
1/ Since automotive scrap tires weigh 20 pounds each on average, dollars per ton is
equivalent to cents per tire.
21 Reference 10.
3/ Reference 11.
4/ Total costs of landfilling whole tires - total costs of landfilling shredded tires.
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effectively banned. Florida and Oregon have required that the tires be reduced in
volume by methods such as slicing or shredding.
Another landfill restriction method, in addition to banning tires or requiring
shredding, is to require that tires be disposed of in tire monofills, either whole or
shredded. This allows precautions to be taken that will keep the tires buried. It also
keeps open the potential for mining the material for some useful purpose at a later
date. Specific rules for tire disposal in monofills will be drafted by Ohio in 1991,
following the completion of a feasibility study that is examining the engineering
properties and leaching potential of shredded tires.
UTILIZATION ALTERNATIVES
In this section, tire utilization methods are described. These include the
recycling of tires into whole tire and processed tire products. The recycling
discussion is followed by a discussion of 'tire utilization methods that capture their
energy value. These are incineration and pyrolysis.
Applications of Whole Waste Tires
Whole waste tires can be used for artificial reefs, breakwaters, erosion control,
playground equipment, and highway crash barriers.
a) Artificial Reefs and Breakwaters. In the late 1970s, the Goodyear Tire and
Rubber Company researched a number of uses for whole tires. Among these uses
were artificial reefs and breakwaters. Goodyear billed these applications as being
major outlets for scrap tires. They claimed that by 1978 they had built some 2,000
reefs. In Ft. Lauderdale, Florida alone they were said to have used 3 million tires
and were adding one million tires per year to that reef alone. Besides stimulating
the fishing industry it was believed that tires would later be mined for their raw
materials. Since that time, enthusiasm for this use has waned and scrap tire reefs are
now only built in minimal numbers.
Breakwaters are barriers off shore that protect a harbor or shore from the full
impact of the waves. Breakwaters using scrap tires have been tested by the U.S.
Army Corps of Engineers and were found to be effective on small-scale waves. It
was recognized at the outset that this application would never use a great number of
scrap tires, but tires perform well in applications where floats are needed. Scrap tires
for breakwaters and floats are filled with material, usually foam, which displaces 200
pounds of water and can be used to float a number of devices such as marinas and
docks and serve as small breakwaters.
Topper Industries of Vancouver, Washington, has patented the concept of a
material-filled floating tire. The concept employs scrap tires as a durable container
for holding the flotation material together (13). Topper Industries is the only
known producer of scrap tire flotation devices and that company estimates that they
29
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Table 8
SCRAP TIRE LEGISLATION STATUS
January, 1991
Draft Proposed Regs Law
Alabama X
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X X
X
X
X
X
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
Wisconsin
West Virginia
Wyoming
Draft - draft being written/bill in discussion
Prop - proposed/introduced in 1990 legislature
Regs - regulated under specific provision of solid waste or other laws (e.g., automotive wastes)
Law - scrap tire law passed
Draft Proposed Regs Law
X
X
X
X
X
X
X
X
X
X
X
X
Source: Scrap Tire News, Vol. 5, No. 1, January 1991
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Table 9
CONTENTS OF SCRAP TIRE LEGISLATION
Arizona
California
Colorado
Connecticut
Florida
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Michigan
Minnesota
Missouri
Nebraska
New Hampshire
North Carolina
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
Wisconsin
Funding
Source
2% sales tax on retail sale
$0.25/tire disposal fee
$1 ,00/tire retail sales
$0.50/vehicle title fee
permit fees/tire storage sites
$0.50/tire retail sales
$1.00/tire retail sales
$1.00/tire disposal fee
state budget appropriations
$0.50 vehicle title fee
$4.00/vehicle title transfer
$0.50/tire retail sales
$1.00/tire retail sales
graduated vehicle regist. fee
1% sales tax on new tires
$1.00/new tire (surcharge)
$1.00/new tire (dspl tax)
$0.50/new tire sales tax
graduated tax per tire size
$0.50/new tire (dspl tax)
$2.00/tire vehicle title fee
Storage
Regs
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Processor
Regs
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Hauler Landfill Market
Regs Restrictions* Incentives
X
X
X
draft
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
R&D grants
grants/loans
grants
grants
grants/loans
grants
grants
funds/testing
grants
funds/collection
grants
$0.01/lb
R&D grants
$20/ton
funds/testing
grants
$20/ton
The majority of states have imposed regulations that require tires to be processed (cut, sliced, shredded) prior to landfilling.
Some of the states allow for storage (above ground) of shreds at landfills. OH, NC, CO are among the states considering or allowing
monofills for tire shreds. Whole tires are discouraged from landfills (in almost all cases) either by law (e.g., MN) or more
frequently by high disposal fees.
Source: Scrap Tire News, Vol. 5, No. 1, January 1991.
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use 30,000 to 50,000 tires per year. These tires are included in breakwaters, marina
and dock floats, buoys, and other flotation applications. Topper Industries, Inc.
obtains its tires from junk dealers within a 100-mile radius of Vancouver,
Washington. They then sell the floats to a market covering primarily the western
half of the United States.
Costs for constructing flotation devices are determined on a dollar per pound
basis. Topper Industries claims a one-half to three-fourth cost savings by using scrap
tire floats over wood, wood-fill, or other alternatives. The tire floats cost approxi-
mately $0.06 to $0.08 per pound, whereas the economically closest alternative, foam-
filled plastic, costs $0.10 to $0.14 per pound of flotation (14).
Breakwaters and flotation devices presently consume approximately 30,000 to
50,000 tires per year. If tire floats were to acquire the major portion of the flotation
market, it may be possible to increase the current tire consumption by a factor of
three to four, which would still be less than 1 percent of the annual generation of
scrap tires in the United States.
Artificial reefs are constructed by splitting tires like bagels leaving about six
inches attached and then stacking them in triangular fashion. Holes are drilled
through this stack and about 45 pounds per tire of concrete are poured in the holes
to anchor the reef. The 1,800 pound 3-foot high reefs are then hauled by barge 4 to 12
miles off the coast and dumped in 60 to 100 foot deep water. They then provide
habitat for marine organisms and fish (14).
The largest operations of building artificial reefs from scrap tires are occurring
in Cape May and Ocean Counties, New Jersey. These two counties consume about
120,000 tires per year in making reefs. Cape May County has a goal of using 100,000
tires per year for reefs, by combining tires with concrete and placing them in the
ocean (15). This is the only disposal option for scrap tires within Ocean County. It is
likely that reefs are being built in other states, particularly Florida, but quantities of
tires used are small and on an irregular basis (15).
In Ocean and Cape May Counties, tires are brought in by individuals or
haulers wishing to dispose of the tires. The counties may have an influx of tires
when area fire departments require that storage sites be abated. Ocean County
charges one dollar per tire to accept the tires, while Cape May County charges $25.25
per ton (equivalent to 25 cents per tire).
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
32
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reefs. But, it is low compared to scrap tires generated annually because artificial reefs
are restricted to fairly calm sandy coastline, where reef development is needed.
Much of the northwest coast has rough water and Oregon has even banned artificial
reefs from their sea waters (17). Cape May and Ocean Counties do not foresee an end
to their activities as long as the state fish and wildlife agency continues to provide
sites to place the reefs.
Costs for constructing reefs are about $3.50 per tire. This cost is somewhat
offset by charging $1 per tire in Ocean County to accept tires or $25.25 per ton to
accept tires in Cape May County. This compares to the average of $45.25 per ton to
landfill the tires in the northeastern United States. Since haulers in Cape May
County save money by taking tires to the reef builders, tire supply is not a problem.
In Ocean County, costs are minimized by using prison labor for building reefs; and a
county owned barge takes the reefs to the dump site (15).
b) Playground Equipment. The only large producer of tire playground
equipment is Tire Playground, Inc. in New Jersey. President William Weisz says
that his company currently uses up to 4,500 truck tires per year, but has used up to
7,500 per year in the past. In addition to this are the small-scale local and backyard
recreational uses of tires. The tire consumption cannot be easily determined, but it
is thought to be small compared to the scrap tire supply. The demand for Tire
Playground's products is declining as the east coast economy improves and schools
and parks select wooden playground equipment. The material cost for the tire
playgrounds is one-fourth of the cost of alternative equipment (18).
Even if the market for tire playgrounds were developed completely, it would
require less than a million tires per year, which is less than one-half percent of the
annual generation.
c) Erosion Control. The California Office of Transportation Research has
designed and tested several erosion control applications of scrap tires. Scrap tires
were banded together and partially or completely buried on unstable slopes in tests
conducted between 1982 and 1986. They found that tires used with other
stabilization materials to reinforce an unstable highway shoulder or protect a
channel slope remained stable and can provide economical and immediate
solutions. Construction costs were reduced from 50 to 75 percent of the lowest cost
alternatives such as rock, gabion (wire-mesh/stone matting), or concrete protection.
Information on the applications has been distributed since 1988, but it is difficult to
determine the number of times these designs have been used. John Williams of the
California Transportation Laboratory believes it would be fair to say that fewer than
10,000 tires are used annually for erosion control. He says it is difficult to estimate
the potential annual consumption by this method as tire designs are not always
appropriate and tires for this use may not be acceptable in highly visible areas (19).
d) Highway Crash Barriers. The use of scrap tires as crash barriers was studied
in the late 1970s by the Texas Transportation Institute. They determined that stacked
33
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tires bound by a steel cable and enclosed with fiber glass would reduce or absorb
impact of automobiles traveling up to 71 miles per hour.
Since that time, no widespread use of tires in this application has occurred.
State transportation departments generally prefer sand-filled crash barriers because
they have excellent absorption characteristics and are easier to erect and dismantle.
Applications of Processed Waste Tires
Tire processing includes punching, splitting, or cutting tires into products;
processing tires into crumb rubber for use in rubber or plastic products, railroad
crossings, rubber reclaim, or asphalt paving; and chopping tires into small pieces or
chips for use as gravel or wood chip substitutes.
Various rubber products can be manufactured using rubber from scrap tires to
replace some or all of the virgin rubber or other material in the product. Tires may
be either split, punched, or stamped to yield shapes suitable for fabrication, or the
tires may be processed to crumb size to make new products, usually by mixing with
other materials.
In this section the primary focus is on reuse of the rubber from tires.
However, the fabric and steel may also be recycled.
a) Splitting/Punching of Tires. Splitting involves the removal of the steel
bead and then using a stamp or punch to achieve the desired shape. Splitters
purchase tires on the market either graded or ungraded. They are responsible for
disposal of the part of the tires that are left as well as the unrecyclable tires, so they
generally buy only appropriate tires. For example, steel-belted radials create
problems for the splitters and are usually not wanted.
Products from the splitting of tires include floor mats, belts, gaskets, shoe
soles, dock bumpers, seals, muffler hangers, shims, washers, insulators, and fishing
and farming equipment. The market for this type of product is very limited;
however, one Massachusetts company reports they use 2,000 tires per day to
manufacture fishing equipment, such as net parts, rubber discs, rollers, chain covers,
strips for traps, etc. Because this industry is so diversified and there are no
published data, it is difficult to make good estimates of the nationwide usage of split
rubber products. Estimates made in 1987 indicate the U.S. market for these products
is about 2.5 to 3.0 million tires per year (20). In the absence of additional data, it is
assumed that the markets in 1990 remained at the same level.
b) Manufacture of Crumb Rubber from Scrap Tires. Crumb rubber is made by
either mechanical or cryogenic size reduction of tires. Because of the high cost of
cryogenic size reduction (at liquid nitrogen temperatures), mechanical size
reduction by chopping and grinding is used most often. Typically tires are shredded
to reduce them to 3/4-inch chips. Then a magnetic separator and fiber separator
34
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remove all steel and polyester fragments. The rubber chips are then reduced to
pebbles by a cracker grinder or granulator. A series of screening and regrinding
operations achieves the desired crumb size, which may be 600 to 800 microns. This
rubber may be used in rubber or plastic products, or processed further into reclaim
rubber or asphalt products. A significant portion of the crumb rubber market
demand is met by buffings and peels from retread shops.
Crumb rubber can be mixed with other materials to make new products,
including plastic floor mats and adhesives. It can also be mixed with asphalt as an
additive to make cement products.
1) Crumb Rubber in Rubber and Plastic Products. Crumb rubber may h~
incorporated into rubber sheet and molded products such as floor mats, vehicle
mud guards, and carpet padding or into plastic products, including plastic floor mats
and adhesives. Additional uses that have contributed to the expansion of this
market over the last three years are rubber play surfaces, tracks and athletic surfaces,
and garbage cans. In 1987 about 2.3 million tires (1 percent) were utilized in this
manner. 1990 estimates have risen to 8.6 million tires per year, or 3 percent of the
scrap tires generated that year.
2) Crumb Rubber in Railroad Crossings. OMNI Products, Inc., a
subsidiary of Reidel Environmental Technologies, Inc., has a patented process for
using crumb rubber to make solid rubber railroad crossings (21). The molded panels
fit between the tracks and fasten to the ties. OMNI is operating in three locations:
Portland, Oregon; Lancaster, Pennsylvania; and Annis, Texas. Currently only
buffings from tire retreading operations are being used, but the company is testing
the use of crumb rubber that still contains the fiber.
Rubberized crossings compete with crossings made of asphalt and timbers.
The installed cost of the OMNI product is about 35 percent higher than timber and
about 100 percent higher than asphalt. The manufacturer claims that the life cycle
cost of rubberized crossings can be lower than competing materials because they
expect their product to last about 10 to 20 years compared to 3 to 4 years for asphalt,
depending on the traffic.
In 1990 OMNI used at least 14 million pounds of crumb rubber for railroad
crossings. Another company, Park Rubber Company of Illinois, used less than 1
million pounds of crumb rubber for the same purpose. If 20 million pounds were
used for rubber railroad crossings, this would be equivalent in weight to about a
million scrap automotive tires. However, if only buffings are used, only about 10
percent of each tire is used, and the tire disposal problem is not solved.
There is a potential for growth of the rubber railroad crossing market. There
are 185,800 public railroad crossings and at least as many private ones in the U.S.
Less than 2 percent have rubber crossings. A typical railroad crossing consumes
about 350 pounds of rubber per track foot.
35
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3) Rubber Reclaim. For the traditional rubber "reclaim," crumb rubber
is mixed with water, oil, and chemicals and heated under pressure, thus rupturing
the carbon-sulfur bonds that cross-link the molecular matrix. The resulting partially
devulcanized rubber may be formed into slabs or bales and shipped to manufac-
turers who process and vulcanize it for use as an alternative to virgin rubber to use
in tires or to make mats and other rubber products.
Reclaim rubber tends to lose its elastic properties during processing and,
therefore, is no longer extensively used in tires because of the flex needed. That is, it
does not become like new rubber. However, some new tires routinely contain one
to 2 percent crumb rubber (5).
Because of the increased use of synthetic materials in making new tires after
World War II, the reclaim industry has dramatically decreased in size. During
World War II, about 60 percent of the rubber in tires was reclaimed rubber. Each of
the major tire manufacturers has discontinued operating reclaim plants in the last 8
to 10 years, until now only about one to 2 percent of the raw material for tires is
reclaim. There are currently only two companies that produce reclaim rubber, i.e.,
partially-devulcanized rubber, from whole tires for use in tires and other rubber
products. These companies are Midwest Rubber Reclaiming Co. in East St. Louis,
Illinois and Rouse Rubber, Inc., in Vicksburg, Mississippi (22).
In 1987, the equivalent of 3.4 million tires were consumed for reclaim rubber.
By 1989 this figure had declined to 2.9 million tires (23). The reclaim industry's
production capacity is estimated to be between 100 and 144 million pounds per year,
(5 to 7 million tires per year), indicating a capacity of utilization of about 40 to 60
percent, due to limited market demand. The Department of Commerce is no longer
updating its reclaim rubber production figures yearly. It is estimated that production
remained 2.9 million tires or less in 1990.
A new reclaim producer, Rubber Research Elastomers (RRE) of Minneapolis
declared bankruptcy in August, 1989 (24). RRE, under Chapter 11, is currently
exploring options for restructuring its operations. Since RRE's "Tirecycle" products
have generated considerable interest, the process is worth discussing.
In the Tirecycle process, first developed in 1982, finely ground scrap rubber is
treated with a liquid polymer to form a reclaimed rubber product. RRE literature
claims superior bonding properties and suggests use in tread rubber and other
products including washers, mats, car parts, and tiedowns. The Tirecycle product is
claimed to be useful with thermoplastics such as polypropylene, polyethylene, and
polystyrene, as well as polyvinyl chloride, polyesters, and urethanes.
The RRE facility in Babbitt, Minnesota, financed by St. Louis County and the
state, was envisioned to have a capacity to process three million tires per year, all of
Minnesota's scrap tires. Actual production never reached over 10 percent of that
value.
36
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A study by the University of Minnesota completed May 19,1989 (25),
concluded that there are adequate rubber markets for Tirecycle products, but that the
Tirecycle product performance and delivery often failed to live up to customers'
expectations. The study also concluded that the operation needs a large infusion of
cash (over two million dollars) before reaching 60 percent of capacity and reaching
breakeven conditions under an optimistic scenario. As a result of the University of
Minnesota study, St. Louis County and the state decided not to continue funding the
KRE Tirecycle project.
4) Crumb Rubber Additives for Pavements. Crumb rubber can also be
combined with asphalt for use as a paving material. There are two main types of
processes for doing this. Advantages claimed for both include increased durability,
flexibility, and longevity, when compared with conventional asphalt pavements.
One application, referred to as Rubber Modified Asphalt Concrete (RUMAC), or the
dry process, involves the displacement of some of the aggregate in the asphalt
mixture with the ground whole tires. For this application the tire crumbs or chips
may still contain some of the reinforcing materials such as polyester, fiber glass, and
steel. PlusRide is the commercial name by which one kind of RUMAC is
marketed. The TAK system, a non-patented generic system being tested by the State
of New York and others, is another form. PlusRide and the TAK system each
have a different size distribution of the rubber aggregate in the asphalt mixture.
The second application of crumb rubber in asphalt (also a patented process)
involves the blending/reactivating of a certain percentage of the asphalt cement
with a ground rubber that is free of other tire constituents such as polyester,
fiber glass, or steel. This application is referred to as asphalt-rubber (A-R), the
Arizona process, or the wet process. While A-R typically uses only one-third of the
rubber per mile of pavement that RUMAC uses (assuming equal thicknesses of
material), it has been tested at more locations of the United States over a longer
period of time. In the following pages, the technologies and uses of RUMAC and
A-R are described. This is followed by a brief summary of research on pavements
containing rubber.
(a) Rubber Modified Asphalt Concrete. The PlusRide
technology typically uses 3 percent by weight (60 pounds per ton of total mix) of
granulated coarse and fine rubber particles to replace some of the aggregate in the
asphalt mixture (26). Wire and fabric must be removed from the tire crumb and
the maximum moisture content is 2 percent. The granulated rubber is graded to
specifications, and in the PlusRide system, the aggregate is gap graded to make
room for the rubber to be uniformly dispersed throughout the paving mixture. The
granulated rubber is graded to specifications as follows:
37
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Percent
Sieve Size Passing by Weight
1/4 inch 100
U.S. No. 4 76-100
U.S. No. 10 28-42
U.S. No. 20 16-42
TAK, the non-patented RUMAC system being tested by the New York State
Department of Transportation, uses a uniformly graded rubber crumb, and therefore
does not require gap grading of the aggregate. The New York DOT is testing this
system in highway strips using 1, 2, and 3 percent rubber in total asphalt mix. The
results will be compared with results from PlusRide test strips. It is too early for
any test results, since the strips were laid in the fall of 1989 (27).
The asphalt binder used in both types of RUMAC is the same as that used in
conventional asphalt. Therefore, conventional equipment is used for mixing the
final product. A belt conveyor is used to feed the rubber into the mixer.
The formula for PlusRide was invented in Sweden in the late 1960s and was
patented in the United States by the PaveTech Corporation located in Seattle,
Washington under the trade name PlusRide. Marketing is done by several
companies across the country.
PlusRide modified asphalt is currently being tested in highways, streets,
bridges, and airports. PlusRide and TAK use all the rubber in waste tires,
including the sidewall interliner and tread portions, recycling all but the steel and
fabric. Chief advantages over conventional asphalt are claimed to be increased
flexibility and durability, which make it attractive for rehabilitating road surfaces
with severe cracking.
(b) Asphalt-Rubber. Asphalt-rubber was developed in the late
1960s and has been used primarily in the City of Phoenix, Arizona (28). The asphalt-
rubber process involves the blending of presized granulated rubber into standard
asphalt heated to over 400 degrees Fahrenheit. Blending occurs for about 45
minutes. A-R is produced by one of two procedures. In the Arizona Refinery
procedure, an oil extender is added to the asphalt before heating and adding rubber,
and in the McDonald procedure, kerosene is added to the hot blended mixture.
Either procedure is performed just before application at the job site, as A-R cannot be
stored for more than 3 days without adjustment of the mix.
The composition of A-R is highly dependent on the needs of the project.
Rubber content is generally 15 to 25 percent of the binder by weight and the crumb
size used ranges from fine to coarse in six different sizes. The crumb used is
produced by a crumb rubber company which separates the ferrous ami fabric
38
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materials from the tire and then shreds to a specific rubber particle size. Various
polymers may also be added to the formula. The crack seal industry has many
different mixes from which to choose.
The application process is also dependent on the type of project. Asphalt-
rubber used as a seal coat is sprayed on the surface with equipment designed for
asphalt-rubber's high viscosity and need for constant stirring to suspend the rubber.
Hot mix projects require little special equipment as the asphalt-rubber is premixed
with the aggregate and applied in the same manner as a standard overlay (29).
For the more than 20-year history of asphalt-rubber, most applications have
been used for testing or experimental projects. The exception has been the wide use
and success of A-R in Arizona and other southwestern states, including California
and Texas. Some states that have not used A-R extensively in the past are awaiting
material and application specifications to be established (30). This situation may
soon be remedied as the Asphalt Rubber Producers Group (ARPG) is currently
working with the American Society for Testing and Materials (ASTM) and the
American Association of State Highway and Transportation Officials (AASHTO) to
establish specifications for the A-R industry (29).
Applicators with royalty agreements for A-R are located in Phoenix, Los
Angeles, East Texas, Washington, and Rhode Island. These companies are able to
meet the current levels of use competitively. These companies are shown in Table
10.
When A-R is applied, the applicator usually obtains crumb rubber from the
shredder company that is geographically closest to the project site. Since there are a
limited number of crumb rubber shredders, scrap tires may not originate from the
community buying the A-R application. If, for example, a city or state buying an
A-R application is located outside the 200 to 300 mile radius of the crumb producer
who is providing the crumb rubber, it is likely that their own scrap tire supply is not
being consumed.
The A-R process consumed 1.9 million tires in its U.S. production in 1989
(31), which is almost a 60 percent increase over 1987. In 1986, 35,000 tons of A-R
were placed by five U.S. applicators. In 1989, 47,000 tons were used, and the ARPG
predicts about 65,000 tons will be used in 1990 (31).
The longer pavement life claimed for asphalt rubber is attributed to higher
viscosity and impermeability of asphalt-rubber. These properties have decreased
thermal cracking, potholing, deformation, and reflective cracking in most states in
which tests were performed. Studies by the Alaska Department of Transportation
showed decreased stopping distances as a result of asphalt-rubber being more flexible
and preventing ice formation (32).
39
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Table 10
ASPHALT-RUBBER APPLICATOR COMPANIES
International Surfacing Phoenix, Arizona
Cox Paving Company Blanco, Texas
Eagle Crest Construction Company Arlington, Washington
Manhole Adjusting Contractors Monterey Park, California
Asphalt Rubber Systems Riverside, Rhode Island
Source: Asphalt Rubber Producers Group
The Asphalt Rubber Producers Group (ARPG), which promotes asphalt-
rubber, suggests that the doubled life of A-R pavements provides two options for
departments of transportation. In one case, an inexpensive application of A-R
applied to severely deteriorated pavements can extend that pavement's life. For
new pavements, they suggest a long-term cost benefit by performing more than
twice as long as a standard pavement even though its original cost was less than
twice as much.
(c) Research and Demonstration of RUMAC and Asphalt-
Rubber. Procurement guidelines for the use of rubber in asphalt were proposed by
the U.S. EPA in 1986, but have been tabled since that time because many state
highway departments felt that not enough research had been completed at that time
to justify promotion of this technology nationally through procurement guidelines.
Questions still remain about the life expectancy, suitability in different climates, and
recyclability.
Research on RUMAC in the United States, beginning in 1981, has been
conducted by a number of institutions and states, including the University of
Oregon, the University of Idaho, the California, Alaska, New York, and New Jersey
Departments of Transportation, and the Colorado Department of Highways. Tests
are still under way, although most test results to date indicate improved durability
and skid resistance and less cracking.
Because the initial cost of PlusRide is higher than conventional asphalt and
because of the long times required for satisfactory testing, it is not being used
routinely at this time. Since 1979, however, this material has been used in over 60
test applications in the United States.
Asphalt-rubber has been tested in at least 25 states over the last 2 decades. It
has been used primarily as a maintenance tool to save existing distressed surfaces,
and most recently as a preventive maintenance tool. It is not being used routinely
in new construction.
40
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One of the concerns regarding both RUMAC and A-R highways is their
recyclability. Old asphalt is typically heated and mixed with fresh material to create
new asphalt. There is concern that when the rubber modified asphalt is reheated, it
may catch fire or produce noxious smoke. The industry claims that this will not
occur, and that recycling of rubberized asphalt has been successfully done in Sweden.
However, many state highway departments are not yet convinced.
In 1985 the New York State Department of Transportation indicated a
possibility of health and environmental problems in using rubber in asphalt. They
felt the presence of carbon black, carcinogens, and unhealthy fumes may cause
problems in utilizing rubber in asphalt (33). Since 1985, New York has had no
evidence that rubber significantly increases the health problems of asphalt (27). The
California Department of Transportation, which has experience with both RUMAC
and A-R, indicated they are not aware of any additional health problems due to the
addition of rubber (34).
d) Markets and Life Cycle Cost of RUMAC and Asphalt-Rubber.
Asphalt-rubber is diversifying into new markets with the construction of
geomembranes for lining of evaporation tanks, hazardous waste storage sites, and
ponds. A-R provides impermeable linings which restrict the movement of the
substances to be contained (33). Though the A-R applicators promote these
applications, they realize they are only a small supplement to the pavements
market. The greatest potential for utilizing large quantities of asphalt-rubber
remains in road, runway, and parking lot construction applications.
Pavement applications for asphalt-rubber include:
Crack and joint sealants
Seal coats
Interlayers
Hot mix binder in overlays.
Crack and joint sealants are applied only on cracks and joints. Seal coats
include hot asphalt-rubber sprayed on the surface followed by precoated aggregate.
Interlayers are the application of seal coats followed by either a standard overlay or
an asphaltic-rubber overlay. Asphalt-rubber, when blended with an aggregate hot
mix at about 9 to 10 percent by weight, serves as a binder in the thin overlay applied
to the road surface. The hot mix binder holds the greatest potential for using large
quantities of scrap rubber because of the thickness and quantity of the overlay.
Fifteen to 25 percent of the binder is crumb rubber. Current investment and
research projects are concentrated in this use of asphalt-rubber (29).
A general rule in comparing costs of standard asphalt and A-R or RUMAC is
that the rubberized material will be between 40 and 100 percent higher than the cost
of standard asphalt. The lack of an exact cost ratio between the alternatives is caused
by the variability in the cost determining factors that are involved. In a California
41
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study in 1988, standard dense graded asphalt concrete controls cost approximately
$3.04 per square yard, while equal thicknesses of asphalt-rubber and RUMAC
applications averaged about $6.13 per square yard (36). Table 11 compares cost
estimates from five areas, including New York, California, Washington, Phoenix,
and Wisconsin.
Only Wisconsin has had negative results with regard to service life of asphalt-
rubber. Wisconsin tried rubber mixed with recycled asphalt and got 10 times more
cracking than with recycled asphalt alone. They now have 3 new A-R projects
planned for 1990, using new asphalt. ARPG defends pavement life increases of two
and one-half to three times greater than conventional. Standard pavements
consistently last 10 to 12 years, whereas asphalt-rubber pavements last 20 or more
years. The ARPG claims that if an asphalt-rubber pavement were designed to last
the same length of time as a standard pavement by making the layer thinner, the
costs will be the same.
The increased pavement life can be attributed to higher viscosity and
impermeability of rubberized asphalt. These properties have decreased thermal
cracking, potholing, deformation, and reflective cracking in most states in which
tests were performed. Studies by the Alaska Department of Transportation showed
decreased stopping distances as a result of rubberized asphalt being more flexible and
preventing ice formation (37).
c) Lightweight Road Construction Material. Since 1986, the State of
Minnesota has been using chipped tires as a lightweight fill material where roads
cross marginal subgrade (38). In some areas of the country, this technology has
potential for recycling a large number of tires. This technology was developed when
the Department of Natural Resources, Division of Forestry, was interested in
developing low cost means for crossing peat and other soft soils. Wood chips are
often used for this purpose. Because wood chips and rubber chips are lightweight
compared to gravel, settling of roadways is greatly reduced.
Rubber chips for this technology are coarse shredded to four to six inches in
diameter. Steel may be left in the shredded tires. The cost of these tire chips is very
competitive with wood chips.
Minnesota has used close to a million tires to date for road fill. In one 100-
foot section north of the Twin Cities, where the road crosses a peat bog, 3,000 cubic
yards of tire chips were used. This is equal to about 81,000 tires.
In late 1989, Minnesota tested tires for leachate and found that leaching of heavy
metals, polynuclear aromatic hydrocarbons, and total petroleum hydrocarbons from
tire chips could not be completely ruled out (38). Now the preferred method is to
use wood chips below the water table and tire chips above the wood chips. This is
expected to extend the life of the fill over using just wood chips, since wood chips
degrade in the unsaturated zone.
42
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Table 11
COMPARISON OF RUMAC AND ASPHALT-RUBBER COSTS
WITH STANDARD ASPHALT COSTS
Ratio of
Rubberized Asphalt to Predictions of
Study Standard Costs Life Extension
New York Department of
Transportation (1) RUMAC 1.50 No data yet
California Department of
Transportation (2) Both 2.0 3 times
Washington State (3) RUMAC 1.5 to 2.0 No data yet
Phoenix (4) A-R 2.00 2 times
Wisconsin Department of
Transportation (5) A-R 1.3 to 2.1 No improvement
to slightly
worse
(1) Phone conversation with Tom Van Bramer, NY State DOT, 1990.
(2) Phone conversation with Robert Doty, CA DOT, 1990.
(3) Phone conversation with Dale Clark, WA DOE, 1990.
(4) Phone conversation with Bob Draper, City of Phoenix, 1990.
(5) Phone conversation with Clint Solberg, WI DOT, 1990.
Source: Franklin Associates, Ltd.
The Minnesota Pollution Control Agency estimates that about 20 to 30
percent of Minnesota's tires that are recycled will be used as lightweight roadway fill.
At this time other states are not using this technology. Wisconsin, however, is
planning to evaluate it soon.
d) Playground Gravel Substitutes. At least two companies make a playground
gravel substitute from chipped used tires. Waste Reduction Systems in Upper
Sandusky, Ohio, is marketing colorized tire chips (one-fourth to one-half inch) for
use under and around playground equipment and for running tracks. The tire chips
provide a better cushion than the standard materials such as asphalt, stone, and
wood chips. For this use it is important that all steel is removed from the chips. By
shredding to one-fourth to one-half inch, magnets can be used to remove all steel.
43
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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 childrens1 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).
44
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The primary disadvantage to using tire chips for sludge composting was the
initial cost of the chips. Generally, no equipment modification is required. Tire
chips cost about $60 to $80 per ton; whereas wood chips are around $15 to $20 per
ton. Another disadvantage is that any effect of dilution of contaminants in the
sludge (particularly heavy metals such as lead and cadmium) by wood chips is lost
(41). Since rubber does not decompose, none of it stays with the compost as wood
chips do. Another concern that has been expressed is that zinc from the tires may
somehow adversely affect the compost. It is not clear at this time whether these are
valid environmental concerns.
The Windsor facility no longer composts sewage sludge, so it is not using tire
chips for this purpose. This technology has been considered in Columbus, Ohio;
Nashville, and several other U.S. communities. At this time, however, no facilities
in the United States are known to use this technology on a routine basis.
Combustion
Tires may also be utilized for their energy value, as they have at least as high a Btu
value as coal. This section describes the ways tires are being used for fuel in the
United States.
In the past three years there have been major increases in the utilization of
waste tires as a fuel. Applications have included power plants, tire manufacturing
facilities, cement kilns, and pulp and paper production. These applications have
demonstrated the capability to extract energy value from the tires in an
environmentally acceptable manner, while at the same time alleviating tire disposal
problems in their communities.
Waste tires make an excellent fuel since they have a fuel value slightly higher
than that of coal, about 12,000 to 16,000 Btu per pound. On a national basis, they
represent a potential energy source of 0.07 quadrillion Btu per year, since there are
roughly 242 million tires discarded per year, each weighing about 20 pounds with
15,000 Btu per pound (42). This is equivalent to 12 million barrels of crude oil and
represents about 0.09 percent of the national energy needs. As such, tires compete
with other solid fuels-coal, petroleum coke, and wood wastes (hog fuel).
Burning tires whole obviates the need for expensive shredding operations.
However, the burning of whole tires requires a relatively sophisticated high
temperature combustion facility to keep emissions within environmental limits. It
also requires equipment capable of handling the whole tires and feeding them into
the combustion chamber.
Most of the plants currently burning tires for fuel do not have the capability
to burn whole tires. Instead they must burn tires that have been shredded into
chunks. In this form it is known as tire-derived fuel (tdf). The size of the pieces can
vary from 2 inches to 6 inches, depending on the shredding operation. Typically,
45
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the rubber chunks also contain steel wire from the tire beads and steel belts.
Removal of the wire involves an expensive process, which requires fine shredding
and the use of powerful magnets. Wire-free tdf is considerably more expensive.
In the sections which follow, the use of tires and tdf in various combustion
facilities is discussed:
Power Plants
Tire Manufacturing Plants
Cement Kilns
Pulp and Paper Plants
Small Package Steam Generators.
a) Power Plants. In the past three years major tire-burning power plant
projects have been initiated by Oxford Energy, a company which is headquartered in
Santa Rosa, California. Oxford Energy built a 14 MW power plant in Modesto,
California, and they have operated it since 1987 (43). Recently, they began
construction of their second plant at Sterling, Connecticut, with a 26 MW capacity
(44). They have also initiated efforts for a third plant, a 26 MW unit near Las Vegas,
Nevada.
Oxford Energy has pursued a strategy of developing an integrated waste tire
utilization system (45), as shown schematically in Figure 4. Their philosophy is to
collect and sort the waste tires, utilizing them for fuel or other applications, with no
tires going to landfills. This approach includes culling out the tires in best
condition, which can be sold as used tires or retreadable casings. The majority of the
tires are used in a whole-tire-to-energy plant. Some tires are selected as raw material
for manufacturing processes involving stamping, peeling, or buffing. Other tires are
shredded for fuel for cement plants or pulp and paper plants.
1) Modesto Power Plant. The Modesto Energy Project of Oxford Energy
is currently the world's largest tire-fueled power plant. The plant is located in
Westley, California, about 90 miles east of San Francisco. It consumes approxi-
mately 4.9 million tires per year.
The Modesto plant utilizes a technology that has successfully operated at the
Gummi Mayer tire facility in West Germany since 1973. The combustion system,
which is shown schematically in Figure 5, operates at temperatures over 1,800
degrees Fahrenheit. There are two tire incinerators, each with an associated boiler.
During combustion, the tires are supported on a reciprocating stoker grate. The
grate is made of bars of high temperature metal, which can survive continued
operation in the extreme heat. These high temperatures provide for complete
combustion of the tires, while minimizing emissions of dioxins and furans (46).
The grate configuration provides for air flow above and below, which aids
combustion and helps to keep the grate cool. The grate also allows the slag and ash
46
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r
USED TIRE
MARKET
COLLECTION &
TRANSPORT SYSTEM
(150 MILE RADIUS)
FUEL STOCKPILE
| RETREADERS
BUFFING
DUST
COLLECTION
STAMPING
WHOLE TIRE
TO
ENERGY
PLANT
GRANULATING
SHREDDING
CRUMB
RUBBER
VIANUFAC
TURED
PARTS
ROAD
SURFACE
CEMENT
AGRICUL-
TURAL
BUILDING
MATERIAL
SOIL
ADDITIVE
SMELTERS
UTILITY
Figure 4. An Integrated Tire Utilization System Source: Oxford Energy Company
47
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STEAM
GENERATION
EMISSION
CONTROL
SYSTEM
BOILER
STEAM
TO STEAM
TURBINE
GENERATOR
EXHAUST
STACK
00
TIRE FEED
HOPPER
Figure 5. Schematic of a Tire Incineration Project
Source: Oxford Energy Company
-------
to filter down to a conveyor system, which takes them to hoppers for by-product
sales to off-site users.
The hot combustion gases rise to enter the boiler, producing superheated
steam. Each incinerator has its own boiler, and they both feed steam to the same
turbine generator. It produces 14 MW of power, yielding 100 million kilowatt hours
each year under normal operations. The power plant includes a full pollution
control system, with flue gas desulfurization, thermal de-NOx, and a fabric filter
baghouse.
In January and March of 1988, Radian Corporation made a comprehensive
series of performance measurements on the air pollution control system at Modesto
(47). As shown in Table 12, the measurements included chlorinated dibenzo-p-
dioxins (CDD), chlorinated dibenzofurans (CDF), polycyclic aromatic hydrocarbons
(PAH), polychlorinated biphenols (PCB), total hydrocarbons (THC), ammonia, NOX/
sulfur trioxide, sulfur dioxide, hydrochloric acid, carbon monoxide, and particulate
matter.
The measurements determined that the plant was operating within the
permitted levels for all criteria pollutants. The high temperature combustion was
found to be very effective in controlling the emissions of dioxins and furans, and
their combined emission rate was less than one hundredth of the permitted level.
The only part of the control system found to be under-performing was the thermal
de-NOx system. Radian's measurements showed a three-day average of 384.3
pounds per day for NO2, which was below the permitted level of 500 pounds per
day, but it required the use of offsets which Oxford Energy had previously
purchased. The operation of the thermal de-NOx was also found to require more
ammonia than expected and ammonia emissions exceeded the limit in some of the
runs. Later the cause of the under performance of the de-NOx was traced to the
buildup of a white powder residue within the walls of the incinerator. This caused
an increase in radiant heat transfer to the region where the de-NOx was operating,
increasing the temperature and adversely affecting its performance. Oxford has
installed soot blowers in the incinerator to prevent the white powder buildup. This
is expected to improve the performance of the de-NOx to operate at design levels.
At the Modesto plant, all the by-products can be recycled (48). The steel slag
from the incinerator, which contains the steel from the tire belts and beads, is being
sold for use in cement production or road base. The zinc oxide from the baghouse
can be used in zinc production or as part of a fertilizer. Currently all of the zinc
oxide is being sold for zinc production. The gypsum generated by the scrubber can be
used in wallboard production or as a soil conditioner. Currently all of the gypsum is
being sold as a soil conditioner.
49
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Table 12
SUMMARY OF MEASURED EMISSIONS AT THE CONTROL DEVICE OUTLET
Parameter
CDD
CDF
PAH
PCBa
THCb
NH3
NOX
S03 (CCS)
SO2(M8)
SO2 (CEM)
HC1
CO
PM- Front 1/2
-Back 1/2
-Total
Total Metalsc
Particle Sizing
Emissions
0.515 ng/sec
1.69 ng/sec
61.6 ug/sec
3. ug/sec
0.239 ppmv@12%CO2
63.9 ppmv@12%CO2
49.54 ppmv@12%CO2
45 ppmv @12% CC>2
4.2 ppmv@12%CO2
3.76 ppmv @12% CO2
<3.5 ppmv@12%CO2
52.59 ppmv@12%CO2
0.00190 grains/dscf
0.000418 grains/dscf
0.0023 grains/dscf
48.4 mg/sec
grains/dscf
0.423
Factor
9.85E-03
3.23E-02
1.18
5.74E-02
64.8
0.037
38.6
5.56
4.56
4.08
<2.24
24.9
2.75
0.605
3.36
0.92
50% cut point
0.086 um
Units
ug/MMBtu
ug/MMBtu
mg/MMBtu
mg/MMBtu
mg/MMBtu
lb/lbNH3 injected
g/MMBtu
g/MMBtu
g/MMBtu
g/MMBtu
g/MMBtu
g/MMBtu
g/MMBtu
g/MMBtu
g/MMBtu
g/MMBtu
Percent Less Than 2 um
79.9%
Ib/day
9.81E-08
3.22E-07
1.17E-02
5.71E-04
0.646
181.8
384.3
55.4
45.4
40.6
<22.3
247.8
25.5
5.7
31.2
9.2
aData obtained from Engineering-Science.
^Expressed as parts per million methane.
cEstimated based on inlet concentrations and particulate reduction.
Source: Reference 47 (Oxford Energy Modesto facility).
-------
The power generated at Modesto is sold to Pacific Gas & Electric Company.
Oxford has a long-term agreement with the utility to provide electric power. In
1989, the buy-back rate was 8.3 cents per kilowatt hour.
The success of the Modesto plant showed that whole-tires-to-energy plants
can be built and run profitably in the U.S. The characteristics of the Modesto plant
which made this possible are:
Technology for burning tires economically and within
environmental limits
Buy-back rate from the utility which is high enough to make
the plant profitable
Supply of tires to fuel the plant and provide
sufficiently high tipping fees.
Oxford Energy was able to provide all these features in siting their plant at Modesto.
They located the plant at the Filbin tire pile, which is estimated to have over 35
million tires. In addition, they were able to integrate the plant into their overall tire
collection and processing business and earn revenue from a continuing stream of
tipping fees and collection fees to dispose of tires from tire dealers, recappers, and
other sources in the area.
2) Sterling Power Plant. Oxford Energy has begun construction of its
Exeter Energy Project in Sterling, Connecticut. The construction is being financed
with $55.3 million of tax-exempt bonds issued by the Connecticut Development
Authority and $42.2 million in debt instruments from Sanwa Bank and Zurn
Industries (49). Zurn Industries is the construction contractor for the project. The
plant will be similar in design to the Modesto facility, but will have roughly twice
the capacity.
It is planned to begin commercial operation in 1991, with a buy-back rate of 6.7
cents per kilowatt-hour for the generated electricity. The buy back rate gradually
increases over time, reaching 13.6 cents per kilowatt-hour in 2005. It is anticipated
that in addition to whole tires, the plant will also be able to burn tdf for
approximately 25% of the Btu value. This feature is important for the Sterling
plant, since Oxford Energy has been collecting and shredding tires for several years
in anticipation of the construction of the plant. The 26.5 MW plant will consume
about 9-10 million tires per year from the continued collection and processing of
tires from Connecticut and the surrounding New England area.
3) Erie Power Plant. In July 1989, Oxford Energy announced plans to
build a 30 MW tire-to-energy facility in Lackawanna, New York (50). Oxford Energy
plans that this facility, named the Erie Energy Project, be designed to burn 10 million
tires per year. Under a long-term sales agreement with New York State Electric and
51
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Gas, Oxford Energy plans to sell power at 6 cents per kilowatt-hour, beginning in
1993. Under the agreement, the rate increases gradually over time to 10 cents per
kilowatt-hour in 2005. Oxford Energy has submitted applications to the City of
Lackawanna and the State of New York for the necessary permits. At this time, it is
not clear whether the plant will be constructed, since two other competing waste
projects are also being considered for the site.
4) Nevada Power Plant. Late in 1989, Oxford Energy also announced
plans to build a 30 MW tire-to-energy plant at Moapa, Nevada near Las Vegas. This
planned facility, similar to the Sterling Power Plant, would burn tires from
California and Nevada. The arid environment at the plant site is ideal for
minimization of any mosquito problems associated with tire storage. Oxford Energy
is proceeding with the permitting process and they have already filed for air quality
permits.
In conclusion, whole-tire-to-energy power plants with a reciprocating grate system
and state-of-the-art air pollution controls have proven practical, both in the U.S. and
West Germany. With the completion of the Sterling plant, there will be the capacity
in the U.S. to turn 14 million tires per year into electricity. It must be emphasized
that two keys to successful operation of such plants are proximity to tire sources and
adequate buy-back rates for the electricity generated by the plants.
b) Tire Manufacturing Plants. Two Firestone tire plants have installed
pulsating floor furnaces to dispose of scrap tires and other solid wastes (2). The two
Firestone tire-burning furnaces are located in Des Moines, Iowa and Decatur,
Illinois. They were built in 1983 and 1984, respectively. The furnaces were designed
by Basic Environmental Engineering, Inc. of Glen Ellyn, Illinois.
Currently, only the Decatur incinerator is operating. The Des Moines
incinerator was shut down in 1987 for exceeding opacity limits. The Des Moines
plant produces very large agricultural tires, which are much more difficult to burn
without opacity problems than the passenger tires produced at Decatur. Reopening
the Des Moines incinerator would probably require the addition of a. baghouse,
which is not economically feasible.
Each of the two incinerators has the capacity to burn 100 tons of waste per day
and produce approximately 20,000 pounds per hour of steam for use in the tire
manufacturing process. Twenty-five per cent of the load to the incinerator is whole
tires and rubber scraps. The remainder consists of paper, wood, and miscellaneous
solid waste. The percentage of rubber does not exceed 25 percent so that the flue gas
can stay within the opacity limit. Even though only one quarter of the weight of the
load is tires, the tires account for 80 percent of the Btu consumed by the furnaces.
Both furnaces are fed by the same type of system, utilizing a charging hopper
and a hydraulic ram. The ram pushes the solid waste into a primary combustion
52
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chamber with a stepped hearth. The walls of this chamber are water cooled. Pulses
of air shake up the fuel charge and move it along through the hearth. The hot gas
from the primary combustion chamber goes through three additional combustion
stages before going through a fire-tube boiler. Of the 20,000 pounds per hour of
steam, approximately 70 percent is produced by the fire-tube boiler and 30 percent is
produced by the water-cooled walls of the primary combustion chamber.
The staged combustion system allows the operator to maintain good control
of carbon monoxide and nitrogen oxide, keeping them below environmental limits.
The ash from each plant is removed from the furnace bottom and sent to a water
bath.
The combustion system requires cleaning of the boiler tubes after every 30
days of operation. A typical incinerator run is 7 to 17 days. This type of duty cycle is
suitable for solid waste disposal at the tire plants, although it would be unacceptable
for steady production of electric power.
The incinerator configuration used by Firestone at these two plants appears
best suited to a tire manufacturing operation with capability to use the process
steam. Each of the incinerators has the capacity to handle approximately 500,000
tires per year. No additional tire-burning incinerators using the pulsed hearth
design have been built since these two plants were constructed.
c) Cement Kilns. Cement kilns appear to be very suitable for disposing of
waste tires because these furnaces operate at very high temperatures and have long
residence times. Kiln temperatures are typically around 2,600 degrees Fahrenheit.
High temperatures, long residence times, and an adequate supply of oxygen assure
complete burnout of organics, which minimizes the formation of dioxins and
furans, a primary consideration in solid waste combustion (46). In addition, the
cement production process can utilize the iron contained in the tires' steel beads and
belts. The steel does not change the quality of the cement product, since large
quantities of iron ore are already present as one of the main ingredients.
Figure 6 shows a schematic drawing of a rotary cement kiln. The
configuration shown is typical of those used in the U.S., with no suspension
preheater (51). Limestone and clay are heated together to produce the clinker, which
is later ground with gypsum to produce cement. Various fuels are used in cement
production, including coal, oil, natural gas, and petroleum coke. On a cost basis,
tires are generally the cheapest fuel, unless petroleum coke is available locally.
However, before burning tdf a cement plant operator must consider the capital
equipment expenditures that may be necessary for handling and feeding the tdf.
Generally the fuel change may necessitate obtaining new permits from the state or
local environmental authorities.
At present there are seven cement plants utilizing scrap tires in the U.S., up
from 4 plants in 1989. This contrasts with other countries, where tires have been
53
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n*** V
10&*
***
0*
&
CO^
<*-
G^
PYROPROCESSING
-------
used extensively as fuel in cement plants for many years. In particular, cement
plants in West Germany, Austria, France, Greece, and Japan routinely burn tires
(51). The slower adoption of this means of tire disposal in the U.S. is probably due to
the relative economicsfuel prices are lower here and there are still some landfills
that will accept tires at fairly low tipping fees. In recent years, the slow pace of
permitting the plants to burn tires as well as lack of experience with tire-derived
fuel, has also retarded the U.S. implementation.
A typical example of European experience is Heidelberger Zement in West
Germany. They have been burning tires in cement kilns since 1978, utilizing as
much as 50,000 metric tons per year in six plants. Generally they have kept the tire
percentage of the fuel below 20 percent. They have observed improvement in
kiln performance and more stable operation. They have monitored air pollution
levels from the kilns and observed no problems.
In the U.S. there are approximately 240 active cement kilns (52). Of these,
there are 50 precalciner/preheater kilns built since 1971, which would be the kilns
most likely to burn tdf. However, about 20 percent of these kilns are at locations,
such as the southeast Gulf coast, where they can probably obtain petroleum coke at a
lower price than tdf, and hence they would not be likely tdf buyers. The remainder
could become tdf users if the economics and the environmental permitting
procedures were favorable. If 40 cement plants each used the equivalent of 2
million tires per year, there could conceivably be a national usage of 80 million tires
per year, or one third of the annual number of scrap tires generated.
The first three cement kilns to use tire-derived fuel were Genstar Cement in
Redding, California; Arizona Portland in Rillito, Arizona; and Southwestern
Portland in Fairborn, Ohio. A fourth kiln, Ash Grove, in Durkee, Oregon, burned a
small amount of tire chips in 1990. Other kilns now burning tires for fuel include
La Farge Cement, New Braunfels, Texas; Wholnam, Inc., Seattle, Washington, and
Ideal Cement, Seattle, Washington. In addition, Tilbury Cement Ltd., Vancouver,
B.C., burns some U.S. scrap tires. The experience of the first three operating plants
will be described in the paragraphs that follow.
1) Genstar Cement. The Calaveras Cement plant of Genstar Cement
Company is located in Redding, California, north of Sacramento. The kiln, which
has been in operation since 1981, has a four stage preheater with a planetary cooler
and an in-line calciner. In this configuration, all the gases pass through the kiln,
including the excess air used to burn the precalciner fuel.
Genstar has been burning tdf at the plant for five years. They have built a
feed system that introduces the tdf into the riser duct of the preheater just above the
kiln feed housing (53). This allows the tdf to burn in suspension in the riser gases,
providing efficient combustion. They handle the tdf using the screw feeder and
elevator system shown in Figure 7. With this configuration, they find that the kiln
runs smoothly and there is no difference in the cement product.
55
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TO STAGE I
FROM STAGE II
BUCKET
ELEVATOR
CEMENT
KILN
Figure 7. Tire Feed System Flow Sheet
Source: Calaveras Cement Co.
-------
Currently, they are burning 65 tons of tdf per day at the plant. This averages
about 25 percent of the Btu consumed by the plant. The remainder of the fuel is
coal. With this percentage of tdf the plant meets environmental standards, emitting
95 pounds per hour of NOX and 2 pounds per hour of SO2. The SO2 emissions are far
below the limit of 243 pounds per hour. At its current rate of tdf usage the plant
burns over two million tires per year.
2) Arizona Portland. Arizona Portland operates a cement plant in
Rillito, Arizona, near Tucson, which has been burning tdf since 1986. They have a
different kiln configuration from Genstar and they use a different tdf feed system.
They feed the tdf into the flash calciner at the back end of their system. Until
recently, they had been using an air lock system to feed tdf into their calciner at a
rate of 2 tons per hour. However, they had problems with the pneumatic feed
system. Pieces of steel wire from the tdf repeatedly plugged up the elbows in the
feed path. Because of these problems they decided to install a mechanical feed
system instead.
With the conversion to a mechanical feed system, they expect to double their
tdf feed capacity and run 4 tons per hour. This should result in a considerable fuel
cost savings, because they can obtain tdf for about $1 per million Btu, whereas they
would otherwise be burning more coal which costs about $2 per million Btu. With
the new configuration they could obtain 10 percent of their heating value from tdf,
10 percent from natural gas, and 80 percent from coal. Both their old and new
configurations utilize 2-inch by 2-inch pieces of tdf. With the new capacity Arizona
Portland could increase its capacity to over 3 million scrap tires per year. In 1990,
Arizona Portland utilized approximately 1 million scrap tires (54).
3) Southwestern Portland. The Southwestern Portland Cement Plant,
located in Fairborn, Ohio, has been operational since 1934. Whole automobile and
small truck tires have been burned at the plant on a sustained basis since June, 1989
(55).
The kiln, 220 feet long and 15 feet in diameter, is equipped with a four stage
preheater similar in layout to the Genstar plant. Whole tires are fed, one at a time,
into the riser duct just above the kiln feed housing through a trap door and
isolation chamber. Tires are handled using a conveyor and elevator system that
picks up one tire at a time.
Burning whole tires rather than tire chips saves shredding costs, but
transportation costs may be higher, depending on the distance between the cement
kiln and the tire supply. The feeding mechanism for whole tires is also more
expensive than for chips, because a seal must be provided to prevent leaking cold air
into the process with the tires.
In summary, cement kilns appear to offer an excellent market for the disposal
of waste tires. At present only two plants burning tire chips and one burning whole
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tires have long-term operating expense, but their good results apper to offer
promise for an expanded market. The two kilns burning shredded tires use tdf
supplied by an Oxford Energy subsidiary instead of whole tires, which has simplified
their tire fuel handling and obviated the need for extensive capital equipment. The
total amount of scrap tires used by these seven plants is at least 6 million tires per
year.
d) Pulp and Paper Production. There are many furnaces at pulp and paper
plants which are configured to burn wood waste, which is also known as hog fuel.
Often these furnaces can be fed tdf without major capital equipment changes.
Sometimes a pulp and paper plant will choose to burn only wire-free tdf, with all
the pieces of steel beads and belts removed. This type of tire fuel usually costs about
50 percent more than ordinary tdf, because of the extra processing costs involved in
finer shredding and removing the steel pieces by magnetic separation. The choice of
the more expensive wire-free tdf is indicated in cases where the feed system for hog
fuel has a tendency to get plugged up by pieces of wire. There are also pulp and
paper plants that sell their furnace ash to farmers for agricultural uses. Sometimes
the farmers want the ash to be free of iron, a condition that can only be met by using
wire-free tdf.
1) Tire-Derived Fuel Supply. At present there are probably about a
dozen pulp and paper plants burning tdf, with several of them in the states of
Washington, Oregon, and Wisconsin. The companies marketing over a million
tires per year of tdf to the pulp and paper plants are:
Waste Recovery, Inc., Dallas, Texas
Oxford Energy, Santa Rosa, California
Maust and Sons, Inc., Preston, Minnesota
Emanuel Tire Company, Baltimore, Maryland.
It is estimated that the use of tdf in the pulp and paper industry accounted for
about 12 million waste tires in 1989 (56). It is estimated that at least 12 million scrap
tires were utilized for fuel by pulp and paper plants in 1990.
2) Use of Tire-Derived Fuel. Measurements of emissions from burning
tdf with hog fuel in furnaces in the pulp and paper industry indicate levels generally
similar to those measured from burning hog fuel alone, with some increase in
particulate. Tests on two hog fuel furnaces run by the State of Washington
Department of Ecology found that they both were capable of burning; tdf as auxiliary
fuel without significantly increasing the emission of polynuclear aromatic
hydrocarbons (PNA) (57). They did, however, find some increase in particulate
emissions29,000 grams per hour with tdf versus 21,000 without for the first furnace
and 7,000 grams per hour with versus 5,000 without for the second furnace. As
expected, there was an increase in zinc emissions22,200 grams per hour with tdf
versus 1,400 without for the first furnace and 1,400 grams per hour with tdf versus
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210 without for the second furnace. The levels of vanadium, nickel, lead,
chromium, and cadmium were found to be much higher in burning oil than in
burning tdf.
Tests were also performed on a Minnesota boiler equipped with a
multicyclone and scrubber that normally burned a combination of coal, tree bark,
and sludge (58). The measurements made by Pace Laboratories showed that with 15
percent tdf the particulate level rose to 0.09 pound per million Btu, compared to 0.05
pound per million Btu without tdf. The levels of SO2 and NOX showed smaller
increases, and polynuclear aromatic hydrocarbons were below detectable levels.
Particulate measurements on two boilers at a pulp and paper mill in Oregon
showed similar results (59). The first boiler emitted 39 pounds per hour of
particulate when burning hog fuel and 73 pounds per hour when 1 percent tdf was
used. The other boiler showed 27 pounds per hour of particulate with 100 percent
hog fuel, 46 pounds per hour with 1 percent tdf, and 57 pounds per hour with 1.5
percent tdf.
Experience in the pulp and paper industry has shown that hog fuel boilers can
use tdf for up to 15 percent of their fuel value. The percentage can be adjusted to
meet operational and environmental limits (42).
e) Small Package Steam Generators. Foreign manufacturers produce various
small package steam generator units which are capable of burning tires. Eneal
Alternative Energy of Milan, Italy manufactures a unit which can burn 200 tires per
hour and produce 22,000 pounds per hour of process steam. However, none of the
Eneal units has operated in the U.S. to date. There is currently only one small
package generator operated in this country~a Japanese system operated by Les
Schwab Tires, a retreader in Prineville, Oregon (42).
The Oregon installation uses a 25 tire per hour unit manufactured by Nippo
in Japan and marketed in the U.S. by Tsurusaki Sealand. The unit has been in
operation since 1987 with moderate success, but no U.S. company has yet decided to
purchase another one. The draft configuration in the unit allows it to burn at 2,000
degrees Fahrenheit and produce 100 psig process steam. The unit has a Cleaver
Brooks waste heat recovery boiler and a bag filter. Whole tires are automatically fed
into the unitboth automobile tires and light truck tires. The State of Oregon
Department of Environmental Quality has approved the operation of the unit.
To summarize the combustion alternative, various combustion installations
throughout the country appear to be increasing their consumption of waste tires.
The largest tire combustion facility in the world is now beginning construction~the
Oxford Energy power plant at Sterling Connecticut, which will burn 9-10 million
tires per year. When it is completed, it will bring the total of tires annually
combusted for fuel to approximately 30 million.
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Pyrolysis
Pyrolysis of tires involves the application of heat to produce chemical changes
and derive various products such as oil and carbon black. Although several
experimental pyrolysis units have been tried, none has yet demonstrated sustained
commercial operation. The oil produced by the process would have to compete
with oil conventionally produced from crude, at its current prices. There is also the
problem of marketing the char by-products, whose prices are highly dependent on
quality.
The history of tire pyrolysis projects to date indicates that the problems
blocking them have been technical and economic (60). These include the problems
of upgrading the carbon black by-product while keeping down the operating cost of
the process and the capital cost of the plant.
Recently, there has been a technical advance in char upgrading that may help
to make tire pyrolysis economically feasible (61). In 1987, American Tire
Reclamation (ATR) filed for a patent on a method of reclaiming carbon black from
discarded tires. This method is intended to separate the char into a medium grade
(Grade A) carbon black and a low grade (Grade B) char residue containing 15 percent
ash. This classifier produces a carbon black with the particle size, consistency, and
purity that are suitable for a semi-reinforcing filler of medium strength.
The main test for quality of a carbon black by-product is the strength it imparts
to the rubber products made from it. The laboratory test involves using the carbon
black sample in a recipe for styrene butadiene rubber (SBR) and then strength testing
the resulting rubber samples. In such tests the samples made from ATR's by-
product carbon black were not quite as strong as those made from a standard grade of
carbon black known as N-774, but they were stronger than those from the N-990
grade. American Tire Reclamation calls its by-product carbon black ATR077. The
strength of specimens made from ATR077 is about 2,300 psi, compared to about 3,100
for N-774. Specimens made from ATR077 are about 50% stronger than those made
from ordinary carbon black derived from a tire pyrolysis char.
American Tire Reclamation has sent out samples of ATR077 for inspection
and testing by more than twenty carbon black users. On the basis of the quotes
obtained from potential buyers, they believe that they can sell all their potential
production of ATR077 at $0.13 per pound or higher. With its acceptable
strength characteristics and its competitive price, ATR077 should have a broad
market in non-critical rubber parts, although not in tires. ATR077 can also be used
as a carbon-black filler for blending black plastics, such as plastic pipe.
Up to now, ATR077 has been produced only in a batch process, starting with
char shipped from remote pyrolysis sites. American Tire Reclamation is currently
planning to build a continuous classifier plant at a downtown Detroit location. This
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classifier is expected to have a capacity of 2 tons of char per hour. Present plans call
for the continuous classifier plant to be built in 1991 and then to run for at least six
months using tire pyrolysis char shipped from remote locations. If the continuous
classifier runs are successful and the ATR077 can be sold profitably, the machinery
will probably be moved to a pyrolysis plant and become part of an integrated
operation.
In the past several years, tire pyrolysis has not looked profitable, primarily
because of the technical problems of upgrading the char. The next few years should
determine whether ATR's new char classification technology can help to overcome
these problems.
Up to as recently as a year ago there were no commercially operating tire
pyrolysis units in the U.S. Since then, however, at least one facility, in Oregon, has
commenced operation. Research and demonstration work by several entrepreneurs
is described below:
a) Baltimore Thermal of Baltimore, Maryland indicate that they intend to
build a 3.5 million tire per year pyrolysis plant, which they expect to put in operation
in 1991. They plan to build the plant at a site in Maryland, which is still to be
determined, and produce an oil product similar to #6 fuel oil. They are considering
using the by-product separation technology developed by American Tire
Reclamation for upgrading the carbon black product (description provided above).
b) J. H. Beers, Inc. has a small experimental tire pyrolysis unit at Wind Gap,
Pennsylvania. This unit uses tire pyrolysis technology from Nu-Tech Systems of
Bensenville, Illinois. Experimental runs of this unit indicated that all air pollution
emissions were within allowable limits and the unit was granted an operating
permit by the Pennsylvania Department of Environmental Resources. The unit
emitted 102 ppm of sulfur dioxide, well below the allowable level of 500 ppm. The
unit also emitted 0.002 gr/dscf of particulate, far below the limit of 0.04 gr/dscf. At
this time, there are no indications of building any commercial pyrolysis plants using
the Nu-Tech technology.
c) TecSon Corporation of Janesville, Wisconsin has developed a continuous
pyrolysis system for converting rubber chips to oil, gas, and carbon black. They call
their technology the "Pyro Mass Recovery System," and they have operated a 100
tire/day pilot plant. At this time it is not clear whether their technology will be used
in a commercial tire pyrolysis plant.
d) Conrad Industries of Chehalis, Washington has operated a one ton per
hour pyrolysis unit for several years. Their 1,500 degrees Fahrenheit tubular reactor
has been run with shredded tires. Their most recent runs have used other waste
products as the feedstock. At present, it is not clear whether any company plans to
build a commercial tire pyrolysis plant using their technology.
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Besides the companies listed above, who have indicated recent interest
in tire pyrolysis ventures, there are also many companies who have done
experimental work in tire pyrolysis in the past. Particularly noteworthy have been
the efforts by Firestone and TOSCO.
e) Firestone Tire & Rubber Company performed a major cooperative research
program with the U.S. Bureau of Mines in the early 1970s. They developed a 10
tire/day laboratory pyrolysis unit. In their studies, they determined average yields of
pyrolysis products per tire as follows:
1 gallon oil
7 pounds char
3 pounds gas (57 scf)
2 pounds steel and ash.
Generally, most pyrolysis systems have produced similar yields. Thus, it is
important that any successful pyrolysis plant make provisions for selling the by-
products, especially the char.
f) The Oil Shale Corporation (TOSCO) applied their oil shale technology to
tire pyrolysis in 1975. In 1975, they formed a joint venture with Goodyear and built
a 15 ton per day prototype for pyrolyzing waste tires. Each ton of pyrolyzed tires
yielded $49 worth of oil, $60 worth of carbon black, and $2 worth of steel (2).
Apparently, this was insufficient revenue to justify the potential investment of $20
million to build a commercial-size plant. The project was discontinued.
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Chapter 2
MARKET BARRIERS TO WASTE TIRE UTILIZATION
INTRODUCTION
The previous chapter has discussed the current status of utilization of tires.
This chapter will discuss market barriers to their utilization.
There are substantial barriers to the utilization of waste tires. These barriers
can be classified into two main types - economic and noneconomic.
Economic barriers refer to the high costs or limited
revenues associated with various waste tire utilization
methods which make them unprofitable. No tire
processor will invest time or capital unless there is a
sufficient rate of return to justify the efforts.
Noneconomic barriers refer to a number of constraints on utilization.
These include technical concerns such as lack of technical information
or concerns regarding the quality of products or processes. These
barriers also include the reluctance of consumers, processors,
and regulators to employ new approaches or technologies
for aesthetic or other reasons. They also include constraints on
utilization because of health, safety, environmental issues, laws, and
regulations.
The strength and persistence of these barriers is evident from the continuing
buildup of tire stockpiles and dumps over the last several years.
Table 13 summarizes the economic and non-economic barriers that were
identified for each of the tire utilization options examined in this study. An
economic factor that affects all the technologies, is the low tipping fees for all solid
waste, including tires at landfills. Although landfills often charge more for tires
than for other solid waste, disposal costs are generally much lower than the costs for
alternate means of managing scrap tires such as recycling and incineration for
energy recovery.
This chapter places special emphasis on the barriers affecting the two
categories of waste tire utilization that have been identified as having the greatest
potential for using a considerable portion of scrap tires generated: rubberized
asphalt and combustion. Both of these uses have the potential for being used in
many areas of the country and to consume large numbers of scrap tires if the
economic and non-economic barriers can be removed.
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Table 13
SUMMARY OF BARRIERS TO SOLVING SCRAP TIRE PROBLEM
Technology
SOURCE REDUCTION
Design for longer
life tires
Reuse of used
tires
Retreading
RECYCLING
Rubber additives
for pavements
Economic Barriers
Higher cost for tires
Higher fuel
consumption
High cost of matching,
sorting, and
distribution
High cost of recapping
Competition from
new tire prices
(passenger)
(Most good truck
carcasses are retreaded
now)
Initial costs are
about double cost of
alternate materials
Insufficient life-
cycle cost data
available
Capital cost for
equipment modification
Noneconomic Barriers
Rougher riding tires
More tire noise
Safety concerns
Consumer preference for new tires
Consumer attitudes about safety and
reliability
- Long-term testing is incomplete
- Conflicting test results
- States are waiting on other states'
results
- Lack of information transfer among
states
- No national specifications for
rubberized asphalt
- Patents can limit competition
(continued)
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Table 13 (continued)
Ul
Processed rubber
products
Reclaim
Mats
Split tire
products
Railroad
crossings
Playground gravel
substitute
Bulking agent for
composting
Reefs and
breakwaters
High capital
requirement for
reclaim plants
Price competition
from alternate
railroad crossing
materials
Up to 10 times more
expensive than
alternate materials
(gravel, stone, wood
chips)
High cost compared
to the alternative
(wood chips)
Lack of market acceptance for products
requiring structural integrity,
particularly new tires
Does not use whole tire (disposal still
required)
Split tire products limited to wire-free
tires
Product not as familiar to buyers as
traditional playground gravel
Concerns about lead and zinc from tires
Lose dilution effect of heavy metals
(zinc and cadmium) that is obtained with
wood chips
- High construction cost - Not appropriate for all shores (e.g.
northwest coast is too rough)
Playground
equipment
High cost compared
to other materials
Some schools and parks prefer wooden
equipment for aesthetic reasons
(continued)
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Table 13 (continued)
Erosion control - High cost
Highway crash - High cost
barriers
- Highway departments prefer sand-filled
crash barriers
- More difficult to erect and dismantle than
sand-filled
COMBUSTION
Power plants
Combustion at tire
plants
Cement kilns
(continued)
Low utility buy-back
rate for electricity
in many regions of
U.S.
Capital and
operating costs
High cost of air
pollution control
Capital costs for
handling and feeding
Low cost of alternate
fuels (particularly in
areas where petroleum
coke is available)
Expense and downtime
in environmental
permitting process
- Siting problems
- Concerns about the opacity of
stack emissions
- Delays in environmental permitting
procedures
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Table 13 (continued)
Pulp and paper mills - High cost of wire- - Wire in tdf can plug some hog-fuel
free tdf feed systems and limit ash markets
- Handling costs - Particulate emissions higher than
- Low cost of for hog-fuel alone
alternate fuels - Use of new fuel often requires re-
opening of environmental permits
PYROLYSIS - Capital and operating - Upgrading char needs to be commercially
costs demonstrated on a sustained basis
- High cost for upgrading
char by-products
Source: Franklin Associates, Ltd. and Dr. Robert L. Hershey
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Both technologies are commonly used in Europe, but rubberized asphalt usage in most
of the United States is still in the testing stage.
In analyzing the economics of tire utilization, it is helpful to consider each
situation where cost data are available in terms of the profit per tire. Entrepreneurs
will launch a tire processing facility only if the potential profit per tire is high
enough. The profit per tire may be computed from the equation shown below:
P= F + R-C-T-D
where
P is the profit per tire
F is the tipping fee collected per tire
R is the revenue received per processed tire
C is the processing cost per tire for operating the facility
T is the transportation cost to bring in tires
D is the disposal cost for waste products
In the sections of this chapter where data are available, the various options
for processing tires into fuel are analyzed in terms of this tire profit equation.
Clearly, to motivate entrepreneurs, there must be a positive profit per tire for
any feasible utilization method. If the equation yields a negative value (a loss) then
the private sector will not use such a utilization method, and the tires will stay
where they are. Not only must there be a profit, but it must be high enough to give
a good return on the invested capital to build a plant or buy equipment. A rough
method of analyzing the return is to calculate the simple payback period using the
equation shown below.
Payback Period = Capital Invested
Annual Profit
The equation tells how many years it will take before the capital invested in the
plant and equipment will be paid back. Generally, most investors will demand a
payback period of three years or less before they will risk their money. In the electric
power industry, which tends to have stable revenues, a payback period of seven
years may be acceptable. Obviously, any venture which requires a high capital
investment and yields a very low profit will have a long payback period, and the
venture probably will not be financed.
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In the sections which follow, the economic barriers for various waste tire
utilization methods will be discussed. For those methods which seem economically
feasible, the noneconomic barriers will also be examined.
RUBBER ASPHALT PAVING SYSTEMS
Rubber for pavement use is currently experiencing a rapid growth. The
Asphalt Rubber Producers Group (ARPG) claimed a 67 percent growth in 1989 over
1988, and experienced further growth in 1990. Many states have tested asphalt-
rubber for roads, with about a half dozen leading the way. The PlusRide rubber
modified asphalt concrete is not being used routinely at this time. However,
because of the positive results to date, several cities and counties are having streets
and roads built of this material. The TAK system, a non-proprietary type of
RUMAC, is also undergoing testing.
Economic Barriers
The economic barrier to the use of rubber in pavements is the high initial cost
to the highway departments. It is difficult to obtain good data on the capital
investment necessary to convert an asphalt operation to add rubber. But the
consensus from the ARPG and several other sources is that the installation of
rubber asphalt pavements will cost about 2 times as much as standard asphalt.
Although the test results for asphalt pavements containing rubber are not yet
complete, in many cases a factor of 2 or more in pavement lifetime is achieved.
Therefore, if transportation departments evaluate costs over the life of the roads, the
overall costs may be the same or less for rubber asphalt. The ARPG claims that
rubberized asphalt roads cost less on a life-cycle basis.
The entities responsible for highways and roads are usually the state and local
governments. It is difficult for them to justify doubling the highway repair
investment especially if they are not quite convinced yet what the expected road life
is. In addition, governmental officials may be trying to meet goals of a certain
number of road miles paved per year. It may be more difficult for them to make
decreased life-cycle cost their main goal.
Some state government officials have expressed concern that, because the two
most proven forms of rubberized asphalt are patented, prices for this material may
be higher than they would be if the material were not patented. It is estimated that
the royalty adds 35 percent to the cost of asphalt-rubber and 27 percent to Plus Ride
The patent for asphalt-rubber expires in 1991. After that time ARPG expects more
companies to become involved. The TAK process is not patented, but also has not
been tested as long as the patented types of rubberized asphalt.
,TM
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Noneconomic Barriers
One of the major noneconomic barriers to the use of rubber for paving in the
past has been the lack of long-term test results. Some of the roads installed 15 to 20
years ago are still not worn out. Test controls are required because well designed
asphalt roads may also sometimes last that long. Many of the test results are now
available and more states are looking toward A-R and RUMAC. However, not
many states, if any, are completely satisfied with either A-R or RUMAC to the extent
that they are using either on a routine basis to build their new roads,
Some testing in Wisconsin indicated that asphalt-rubber roads may actually
crack before asphalt roads. This temporarily halted activities in that state. However,
after reevaluating their results and results from other states, Wisconsin has just
installed 30 miles of asphalt-rubber roadway and is planning 3 new projects in 1990.
There is a need to summarize the results of asphalt-rubber and RUMAC
research and establish guidelines that would help states use this process. Texas has
already passed procurement guidelines.
Another potential barrier, the ability to recycle pavements containing rubber,
needs to be tested. Given the similarity of the substance to conventional asphalt,
however, it should be a matter of how, not whether, it can best be recycled.
Another barrier is the lack of national specifications for pavements
containing rubber. Some states appear to be waiting for specifications to be written.
The American Society for Testing and Materials (ASTM) has developed a standard
specification (ASTM D-04.45) for asphalt-rubber to be voted on by its members in
1990-91.
When asphalt-rubber (wet process) is applied to pavements, the tires come
from the neighborhood of the nearest shredding/grinding facility. Because A-R is a
patented material, there are only a limited number of shredding companies that
supply rubber for this process. Some state government officials have indicated
concern about whether waste tires from their own state can be used, as opposed to
those tires near the present shredders, which might be located in another state.
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COMBUSTION
Since tires have a Btu value comparable to the best coal, they would be
expected to be an economically attractive fuel in some situations. Recent U.S.
experience has shown economic feasibility for tire-to-energy power plants and for tdf
used in cement kilns and pulp and paper mills. The economic barriers facing these
types of tire combustion will be discussed below. Despite these economic barriers,
the use of tdf has increased over the last year, and this trend is expected to continue.
Economic Barriers
The economic barriers for combustion of tires relate primarily to the limits of
the revenue received for electricity or tdf by the tire processor. The two cases-power
plant and tdf-are analyzed in the sections which follow.
a) Power Plants. The key economic factor for a tires-to-energy power plant is
the buy-back rate granted by the utility. This rate reflects the avoided cost, the cost
per kilowatt-hour that the utility would incur if they built a plant themselves to
generate additional power. Generally, avoided costs are highest in California and
the northeast and lowest in the northwest. For Oxford Energy's Modesto power
plant the rate is 8.3 cents per kilowatt-hour.
In analyzing the economics of the Modesto power plant, the tire profit
equation can be used. The buy-back rate of 8.3 cents per kilowatt-hour means that
each tire consumed will generate revenue of $1.84 from the sale of electricity to the
utility. For tires coming from the on-site tire pile, F = 0, since there is no tipping fee
and T = 0, because there is no transportation cost. We estimate that C = $0.50, the
processing cost per tire for operations, maintenance, labor, and materials. The
estimate of the net disposal cost per tire of fly ash, gypsum from the scrubber, and
bottom ash (taking into account the sales of byproducts) is D = $0.08. Substituting
these values into the tire profit equation yields the following results:
P=F+R-C-T-D
= 0+ $1.84-$0.50-0-$0.08
= $1.26 per tire
Thus the annual gross profit from the Modesto operation is $1.26 x 4.5 million tires
= $5.7 million per year.
Dividing the gross profit into the $38 million capital cost of the plant yields
the payback period.
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Payback Period = $38 million = 6.7 years
$5.7 million
The payback period estimated above shows that the venture is acceptable,
since investors in similar power plants generally want payback periods of 7 years or
less. (The estimates in this chapter have been neither confirmed nor denied by
Oxford Energy. A formal return-on-investment analysis would be necessary to be
really accurate. This would include the financing structure of the venture, interest
rates, depreciation, and tax considerations.)
From the tire profit equation shown above, it is apparent that the Modesto
plant would be more profitable if it burned tires that brought in a tipping fee, rather
than using tires from the Filbin tire pile. Newly brought tires also have a slight
operational advantage since they are cleaner. Because of environmental, health,
and safety concerns, however, it is important that the size of the pile be decreased.
This situation has led to a compromise; Oxford Energy uses some tires from the pile
and some tires from the surrounding area, for which a collection fee has been
charged.
The economic feasibility of Oxford Energy's planned Sterling, Connecticut
power plant can also be analyzed in a similar manner. This plant will have an
initial buy-back rate of 6.7 cents per kilowatt-hour when it starts operation in 1991.
The Sterling plant will cost roughly $100 million. It is estimated that the plant will
consume approximately 9.5 million tires per year and will generate 26.5 MW of
electricity. This means that the revenue per tire is $1.64 from the sale of electricity.
Processing and disposal costs would appear to be similar to Modesto, so we would
again estimate them to be C = $0.50 and D = $0.08. If the average tipping fee is $0.60
per tire and the average transportation cost is $0.05 per tire, the tire profit equation
yields the following:
P = $0.60 + $1.64 - $0.50 - $0.05 - $0.08
= $1.61 per tire
Thus, processing 9.5 million tires per year would bring in a gross profit of $1.61 x 9.5
million = $15.3 million.
The payback period for the Exeter Energy Project at Sterling, Connecticut is
Payback Period = $100 million = 6.5 years
$15.3 million
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Once again there is a payback period less than seven years for a tires-to-energy
project, the kind of payback expected by utility investors.
Note that the financial feasibility depends on having a sufficient utility buy-
back rate. For instance, if the buy-back rate had been $0.04 instead of $0.064 per
kilowatt-hour, then the revenue per tire would have been only $0.98. This would
yield a profit of only $0.95 per tire. Under this lower buy-back rate the annual gross
profit would be only $9 million, and the payback period would be over 11 years.
With such a long payback period the plant would have difficulty attracting
investors. Therefore, the utility buy-back rate is the critical economic barrier in
determining whether a plant is financially feasible.
b) Tire-Derived Fuel. In analyzing the economic feasibility of a tire-derived
fuel venture, the main economic barrier is the price of the competing fuel. For
instance, the cement plants in Texas and Louisiana are often able to obtain
petroleum coke locally, a waste product from the petroleum refining process.
Petroleum coke is a cheaper fuel than tires; therefore, tdf cannot capture this local
market. Similarly, tdf must often compete with coal as the fuel for cement plants.
If tdf is only slightly cheaper, it is hard to justify any capital costs for new equipment
that might be necessary to burn tdf. Obviously tdf becomes more attractive if energy
prices rise.
The tire profit equation can be used to analyze the profit situation for an
entrepreneur considering building a $1 million facility to shred 1 million tires per
year and produce tdf. If he can sell the tdf for $20 per ton, then by the rule of thumb
of 100 tires per ton R = $0.20. Assume that he operates in an area where tire disposal
is difficult and he can collect a tipping fee of $0.70 per tire. For maintaining a steady
flow of tires he may occasionally have to truck them in, with an average transporta-
tion cost of T = $0.05. For the projected shredding operation the processing cost is
C = $0.40. If the entrepreneur is selling tdf to cement kilns, he can leave the wire in
the tdf from the steel belts and beads and D = 0. Substituting these values in the tire
profit equation yields:
P = $0.70 + $0.20 - $0.40 - $0.05 - 0
= $0.45
With a profit per tire of $0.45, his gross annual profit is $0.45 x 1 million tires =
$450,000. Then the payback period on the $1 million facility is
Payback Period = $1,000,000 = 2.2 years
$450,000
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This payback period is fairly attractive for a commercial facility, since it is less
than three years. However, it is dependent on a relatively high tipping fee and a
continuing demand for tdf at $20 per ton. If either of these decreased significantly,
the venture would not be financially feasible.
The tire profit equation can also be used to look at the economic feasibility of
burning tdf from the point of view of a cement kiln operator. For the cement plant
there is no incremental operating cost in labor for feeding the kiln with tdf instead
of coal. There is no disposal cost since the steel wire in the tdf becomes iron oxide,
which is incorporated into the cement product. If the tdf is trucked to his plant by
the tdf processor, then four terms of the equation can be set equal to zero: F =0, C = 0,
T = 0, and D = 0. Thus, for the cement kiln operator, the profit per tire he receives
equals the revenue, which in this case is a fuel cost savings. If coal costs $50 per ton
and he can get the same Btu value with $20 per ton tdf, then his savings is $30 per
ton for using tdf. With the rule of thumb of 100 tires to the ton, R = $0.30.
The tire profit equation becomes
P = 0 -(- $0.30 + 0 + 0 + 0
= $0.30
If the cement operator burns 65 tons of tdf per day, he will burn the equivalent of
about 2.4 million tires per year. His annual fuel cost savings from burning tdf is
$0.30 x 2.4 million = $700,000. If he has to make capital investments of $1.5 million
to set up the feed system for tdf, then the payback period is
Payback Period = $1,500,000 =2.1 years
$700,000
Since this is less than three years, this looks like a fairly attractive investment for
the cement plant operator.
Note that if he could obtain coal for $35 per ton instead of $50 per ton, his
profit per tire consumed would drop to only $0.15 per tire and his resulting payback
period would be over 4 years. Then making the equipment investment to use tdf
would not be economically attractive. This shows the importance of competing fuel
prices in determining the economic feasibility of using tdf.
Burning tdf is often economically attractive for pulp and paper mills. Since
their boilers are generally equipped to burn hog fuel, very little equipment
modification is necessary to burn tdf. Often the competing fuel for the boiler is hog
fuel, which is sometimes more expensive than tdf on a dollars per million Btu basis.
For instance, at $30 per ton for wire-free tdf, the equivalent cost per tire consumed is
about $0.30. The cost for the same fuel value of hog fuel can be as high as $0.45,
when hog fuel is in short supply. If the costs of handling, transportation, and ash
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disposal are the same for tdf as for hog fuel, then for the pulp and paper boiler
operator, the profit equals the fuel cost savings.
P = $0.15
If the pulp and paper mill consumes 500,000 tires per year as tdf, then the annual
fuel cost saving over hog fuel is $0.15 x 500,000 = $75,000.
If $150,000 in equipment changes are necessary to handle the tdf, the payback
period is:
Payback Period = $150.000 = 2 years
$75,000
As shown above, a pulp and paper plant can often burn tdf economically. The
annual cost savings can justify minor modifications to the equipment to handle tdf.
As discussed above, there are currently operating facilities where the
combustion of tires and tdf has proven to be profitable. The economic feasibility of
tires-to-energy plants depends on the buy-back rate for the electricity. For tdf
consumed at cement kilns or pulp and paper mills, the economic feasibility depends
on cost savings over competing fuels. Only a substantial annual cost savings
justifies modifying a plant to handle tdf. The next section discusses the noneco-
nomic barriers that must be considered once it has been determined that tire
combustion is economically feasible.
Noneconomic Barriers
Noneconomic barriers to scrap tire combustion include problems in siting
new facilities and environmental concerns. These two types of noneconomic
barriers are related since objections to siting are usually due to perceived
environmental problems. These noneconomic barriers are discussed below for
power plants and tire derived fuel usage.
a) Power Plants. Tire-to-energy power plants are large facilities which cost
from $30 million to $100 million. They cover a substantial land area and therefore
create considerable public attention. Inevitably, for a potential facility of this size,
there are some neighbors who believe the new plant will affect them adversely.
This is the not-in-my-back-yard (NIMBY) syndrome, which is a barrier for siting
many solid waste facilities.
In attempting to allay the neighbors' fears, Oxford Energy has designed their
plant with more extensive pollution controls than the California regulations would
dictate. They have a scrubber, a thermal de-NOx unit, and a baghouse for reducing
SOX, NOX, and particulates. The high temperature reciprocating grate technology
minimizes the formation of dioxins during combustion. A consultant's study of air
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pollution tests showed the plant to be operating within its permitted limits. The
plant also has continuous emission monitoring (47).
The configuration chosen for the plant produces salable by-products, rather
than waste products. The flyash from the plant is sold to a zinc smelter. The
gypsum produced by the scrubber has been labeled by the state of California as
appropriate for agricultural uses. It is sold as a soil conditioner. The steel slag from
the plant is sold to a cement kiln for use in cement production.
Oxford Energy's strategy for protecting the tire pile from poteivtial fire hazards
includes providing continuous 24-hour surveillance with lighting at night. Guards
in watch towers are equipped with infrared telescopes. The entire facility is
surrounded by an 8-ft chain link fence. Fire hydrants are provided at strategic
locations, connected to emergency water supplies.
In addition to all the investments in environmental control and safety
equipment, Oxford Energy also spent considerable effort to inform the public about
the plant. They led tours of the plant site and made presentations at public
meetings. They also paid for trips to Germany by two Modesto community
representatives to tour the Gummi Mayer tire incinerator that had already been
operating for over 14 years using the same technology. Oxford Energy's efforts were
successful in convincing the plant's neighbors and the permits were granted.
However, the NIMBY syndrome cannot always be overcome by the methods
described above. Oxford Energy Was not successful in launching a plant in the State
of New Hampshire. The air quality and waste management permits were granted by
the State, but a long court battle with the neighbors followed. After another year
and considerable expenditure, Oxford Energy concluded that they would not be
allowed to build.
The main noneconomic barriers to a tires-to-energy plant are the time
required for permitting a plant, and the concerns of neighbors regarding
environmental, health, and safety issues.
b) Tire-Derived Fuel. The use of tdf in cement kilns and pulp and paper mills
faces considerable noneconomic barriers. This typically occurs when a plant is first
considering switching to tdf. At this point new permits are generally required. This
generally requires test burns with air pollution measurements, leading to
expenditures and additional time for testing. Many plant operators would rather
not bother with the disruption and delay, which erodes the projected fuel cost
savings. Thus the producer of tdf may have considerable difficulty convincing a
plant manager to burn the fuel.
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There is a similar situation with pulp and paper mills attempting to burn tdf.
Generally, state and local officials have required test burns to ensure that emissions
are within regulatory limits. Since tdf burned in pulp and paper mills tends to
increase the particulate emissions somewhat, the permits sometimes restrict the
percentage of tdf that may be burned.
Sometimes the stringent procedures required in permitting tdf burning can
have the effect of controlling one pollutant while increasing another. They reduce
any possibilities of increasing air pollution, but at the same time, they force the
remaining tires (after source reduction and recycling have taken place) into the
waste disposal stream.
PYROLYSIS
At this time, there has been very limited commercial operation of pyrolysis
plants in the United States. The primary barriers are economic and technical. In
particular, there has yet to be a commercial demonstration of a process to
economically upgrade the carbon black to a high-quality profitable by-product. Until
such sustained commercial operation occurs, any potential non-economic barriers
constitute a moot point.
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Chapter 3
OPTIONS FOR MITIGATING THE WASTE TIRE PROBLEM
INTRODUCTION
There is now a general public awareness throughout the U.S. that a waste tire
problem exists. However, there is still controversy about the best solution to the
problem and how we get there from here. This chapter provides options to address
the problem. Several of them may need to be utilized to solve the tire problem.
Over 2 billion waste tires have accumulated in the United States. Some are in
carefully controlled tire stockpiles. Many more are in uncontrolled tire dumps.
Millions more are scattered at random in ravines, deserts, woods, and empty lots
across the country. Each year 242 million more scrap tires are generated. Some of
the waste tires are infested with mosquitoes capable of spreading diseases. Large tire
piles often constitute a fire hazard. Most tire and solid waste professionals agree that
a tire problem exists.
Six facets of the tire problem are listed below:
Tires are breeding grounds for mosquitoes. Besides the major nuisance
of mosquito bites, mosquitoes can spread several serious diseases.
Uncontrolled tire dumps are a fire hazard. Fires in tire dumps have
burned for months, creating acrid smoke and leaving behind a
hazardous oily residue. A few tire fire locations have become
Superfund sites.
Tires should be utilized at their highest value. This means reuse or
retreading first, followed by reuse of the rubber to make rubber
products or paving and then combustion and disposal. At present, the
preferred uses do not accommodate all the tires, and disposal must be
utilized to a large degree.
Scrap tires have to go somewhere. They tend to migrate to the least
expensive use or disposal option, and as costs increase, illegal dumping
increases.
Disposing of waste tires is becoming more expensive. Over the past 20
years the average tipping fees for disposing of tires have continually
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increased. This trend is likely to continue as landfill space becomes
more scarce.
Tires take up landfill space. Whole tires are banned from many
landfills or charged a higher tipping fee than other waste; even if they
are carefully buried to prevent rising they are very bulky. Shredded
tires take up less space, but it is space that could be saved if the tires
were utilized as raw material for products or as fuel.
As listed above, the continuing accumulation of waste tires has led to six
concerns of varying severity. Clearly, the mosquito and fire hazard problems are the
most serious of the problems listed. Controlling them in the near term will
necessitate providing adequate safeguards on presently existing stockpiles.
Ultimately, decreasing the waste tire accumulations will involve appropriate uses of
recycling, combustion, and landfilling. The current trends indicate that the quantity
of tires utilized in products is likely to remain smaller than the quantity combusted
or landfilled in the future.
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.
In the first section, the regulatory approaches taken by states are described.
Minnesota, in 1985, was the first state to regulate scrap tires (61). Four years later,
only ten percent of the states had passed scrap tire regulations. By January 1991, 36
states had regulated scrap tires (12). This section describes the types of provisions
included in the state scrap tire regulations, and presents advantages and
disadvantages of these options, where relevant.
The second section presents other regulatory and non-regulatory options.
Some of these have already been instituted at the Federal or State level, and others
are in the form of proposals.
REGULATORY OPTIONS-BASED ON EXISTING STATE PROGRAMS
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).
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As described below, state scrap tire laws may include (1) funding sources; (2)
mandates to clean up tire dumps; (3) scrap tire management procedures including
stockpile, processor, and hauler regulations; (4) market development incentives;
and (5) regulations regarding landfilling of tires.
Funding Sources
Most of the states with scrap tire laws obtain funding through taxes or fees on
vehicle registrations or on the tires themselves. The means of funding state scrap
tire management programs are described below.
a) Taxes or Fees on Vehicle Titles or Registration. Five states have taxes or
fees on vehicle titles. These range from $0.50 to $2.00. In addition the state of
Minnesota has a $4.00 title transfer tax on motor vehicles. Advantages are that these
fees are collected by the government, therefore do not add to the administrative
burden experienced by tire dealers. A disadvantage is that they do not directly tax
tires. In addition, in times of recession, revenue decreases. Another disadvantage is
that this type of law can be difficult for some states to pass because of state
constitutional issues.
b) Taxes or Fees on the Sales of New Tires or the Disposal of Old Tires.
Twelve states have taxes on the sales of new tires, and two states have fees on the
disposal of waste tires. Taxes on the sale of new tires range from 1-2%, and fees
range from $0.50 to $1.00 per tire. Disposal fees on tires range from $0.25 to $1.00 per
tire. Advantages of these types of taxes or fees are that they are assessed directly on
tires. A disadvantage is that they are often collected by the tire dealer or tire
disposer/processor, so there are administrative costs incurred by these inter-
mediaries, before the money is collected by the state government. Some states
arrange for tire dealers to retain a designated percentage of the taxes or fees, to defray
their administrative costs.
c) Fees on the Permitting of Tire Processing or Disposal Facilities, and the Use
of State Budget Appropriations. One state has chosen permit fees on tire storage
sites as a means of creating a fund for managing scrap tires. Another state
appropriates money for scrap tire management out of its general fund (12).
Disadvantages are, however, that funds are dependent on the number of tire-related
permits being granted in the state, or the yearly budgetary process. Taxes or fees on
vehicles or tires may provide more stable means of funding.
Identify and Clean Up Tire Dumps
Most of the state laws set aside a certain portion of the funds for cleaning up
major abandoned tire dumps. As a first step, some states develop an inventory of
the tire dumps in the state. They may then rank them in priority order for clean-up.
Criteria such as the size of the dumps, and proximity to highly populated areas or to
critical natural resources may be used in determining which dumps are cleaned up
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first. Other actions commonly taken are putting fire protection measures in place,
such as installing fire lanes. As the dumps are cleaned up, the tires may be recycled,
utilized for energy recovery, or disposed of in a landfill.
Figures from the state of Minnesota show that tire dumps in that state have
cost an average of $81,250 per site to clean up, or 65 cents per tire. The most
expensive dump cost $300,000 to clean up, and the least expensive one cost $3,000.
From 1988 to August 1990, the state of Minnesota spent 17 million dollars on clean-
up programs to remove and process waste tires (63). These expenditures have
resulted in an estimated 64% of tire dumps (26 sites) either undergoing clean-up or
having completed clean-up. (62). It is clear from these figures that the clean-up of
tire dumps is expensive. It is, however, less expensive than the costs of fighting tire
fires and associated environmental reparations, which Minnesota estimates could
cost more than $2 per tire (63).
Methods for Managing Current Tire Disposal
Most states have developed regulations to manage tire stockpiles and
processing operations. A number of states have also addressed tire haulers in their
regulations (12). These regulations are described below.
a) Stockpile Regulations. Twenty-four states have regulated tire stockpiles
(12). Generally, state, or in a few cases local, regulations limit the size of stockpiles;
limit the length of tire storage; require fire lanes; require the stockpiles to be fenced
in; and may also require permits for stockpiles over a given size. In addition, some
States such as Minnesota require owners of stockpiles to establish financial
responsibility. They must prove they have the funds to completely remove and
dispose of the tires, should the need arise.
b) Processor Regulations. Seventeen states have some type of regulations on
processors (12). States may require processors to obtain permits or merely to register.
Generally, these regulations limit stockpile size, and establish tire management
practices. Processors may also be required to keep records on the source of tires they
receive and the final end-user. Some States have less stringent rules for smaller tire
piles. For instance, the State of Minnesota regulates tire processors storing 500 or
fewer waste tires at a given time, using a permit-by-rule arrangement. Mobile
equipment operators need only notify the State of when and where they will be
operating their equipment (64).
Advantages of these regulations are better control of processing operations,
and disadvantages are the administrative costs to government and industry of these
programs.
c) Hauler Regulations. Eleven States have passed regulations on tire haulers
(12). These may include provisions such as a state-supplied identification number,
and a requirement that only haulers with these ID numbers may take tires. Some
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states require that tire dealers, processors, and haulers all keep records of their
shipments of scrap tires. Generally these records include a contact person, the name
and address of the company receiving the tires, and the quantity of tires. This aids
in both preventing illegal activity, and aids investigations once any laws have been
disobeyed. Again, the balance is between the administative effort and cost by
government and industry to maintain permitting and recordkeeping programs,
weighed against the benefits they provide in encouraging and enforcing good tire
management.
Market Development Incentives
At least twelve states have developed laws incorporating market
development incentives for scrap tires. These fall into three categories: (1) rebates to
tire recyders and users of tires for fuel, (2) grants and loans to encourage businesses
to recycle tires or use them for fuel, and (3) funds for testing innovative uses of scrap
tires. Below, information is provided on the states that have instituted such
programs, how the programs work, results, and advantages and disadvantages.
a) Rebates for Tire Recycling and Energy Uses. Oregon, in 1987, was the first
state to establish a rebate program. Implementation began the following year (62).
Wisconsin and Oklahoma have since passed similar legislation (12). Some of the
money collected by the states for their scrap tire management programs is returned
to entrepreneurs who are recycling tires or using them for energy recovery. At a
minimum, reimbursement is made available at the rate of 1 cent per pound of tire
used. This is equivalent to $20 per ton. Below, information on the administration
of these programs, their results, and their advantages and disadvantages, is
provided.
In all three programs, a portion of the money collected by the state is
redistributed to users of tires. In Oregon and Wisconsin the state performs this role,
and in Utah the funds are distributed through the local Boards of Health.
Each state has somewhat different rules on who is eligible for reimbursement.
The Oregon program provides rebates to end-users of tires, specifically recyclers and
those utilizing tires as fuel. Certain uses of tires, such as retreading, and the use of
rubber buffings from re-treads are not eligible for funding. Artificial reefs made
from tires are eligible in protected coastal areas such as estuaries and bays, but not in
the ocean. Some uses such as paving projects using crumb rubber from tires, are
reimbursed at higher rates. This is because the state would like to encourage
recycling, and because the rebate must be higher to offset the difference in cost to
make the product using rubber compared to the competing conventional product.
The Wisconsin program provides rebates to end-users of scrap tire materials
but not to processors. Processors may, however, benefit indirectly if the end-users
can now afford to pay them more for the processed tire material. Like the Oregon
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program, rebates can be provided to out-of-state end-users that are using Wisconsin
tires.
The Utah program provides rebates to end-users of tires, to tire processors,
and to certain Utah haulers who are taking tires out of state for recycling or for
energy recovery. Utah's legislation includes a sunset clause that ends the rebate
program after five years (66).
An advantage of these rebate programs is that state governments can use
them to directly encourage forms of tire recycling and disposal that they believe are
most beneficial in helping to manage tires entering the waste stream and in cleaning
up tire piles. Representatives from both Oregon and Wisconsin state governments
report that the rebate systems have been very successful in encouraging additional
companies to start using scrap tires, especially for use as fuel. They believe the
rebates have made a strong contribution to the success of their scrap) tire
management programs (65, 66). It is too early for evaluations of Utah's program
because the legislation was passed in 1990.
Some argue that a disadvantage of these programs is that many of the
companies receiving the rebates would be using the tires regardless of any rebates.
In addition, in states in which processors are not eligible for rebates,, some processors
have asserted that they should be allowed to receive rebates. The Wisconsin system,
in which out-of-state end-users can receive rebates for Wisconsin tires, have caused
some difficulties for nearby states. Some of the processors in nearby states prefer to
utilize Wisconsin tires rather than tires from their own state.
Another disadvantage is that at the outset, these programs can be contro-
versial. After such legislation has passed, it takes some time to build up funds for
rebates, meanwhile entrepreneurs may be stockpiling tires so that they can take
advantage of the rebates once they start flowing. In addition, consumers may
criticize a system in which recyclers and waste-to-energy companies are receiving
rebates, while the consumers are paying $1 to $3 to accept their scrap tires (66).
Experience with Oregon's and Wisconsin's programs, however, show that these
may be short-term disadvantages.
b) Grants and Loans by State Governments. At least twelve states have
programs in which grants or loans are available to tire entrepreneurs and to others
who would like to perform research or investigations into uses for tires, or who
would like to start or expand businesses that utilize scrap tires. These programs may
be specifically for scrap tires, or may be part of larger recycling or solid waste
management programs. As of May 1990, Minnesota, Illinois, New York, and
Michigan had both grant and loan programs. In addition, Pennsylvania and New
Jersey have a loan program, and Wisconsin has a grant program (67).
Provisions of these programs vary widely from state to state. Michigan's
program can provide loans for market development research in recycling, as well as
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for product marketing of recycled materials. New Jersey also has financing available
to recyclers. Higher loan limits are available for recycled plastic and tires than for
other recycled materials (67).
Several states provide grants for feasibility studies to investigate recycling
processes and methods, or for feasibility studies regarding new businesses. Grants
range from 50 percent to 100 percent of the cost of these projects or studies (66).
As with any grant or loan program, advantages are that the government is
helping businesses or other entities develop better ways to utilize tires and increase
the number of tires that are recycled or utilized for their energy value.
Disadvantages occur when grants or loans are provided to enterprises that could
have succeeded without the extra help, or to enterprises that falter when the extra
help is no longer available. The cost of administering grant and loan programs is
also a disadvantage.
c) Funds for Testing Innovative Uses of Scrap Tires. Several states have set
aside funds for research and development of innovative uses for scrap tires. A
number of states, including Minnesota, Florida, New York, and Oregon, have been
testing rubberized asphalt. Several states have been evaluating air emissions from
the incineration of tire-derived fuel in facilities such as cement kilns, pulp and
paper plants, and power plants for electricity generation.
Regulations Regarding the Landfilling of Tires
Many states have passed laws regulating the landfilling of tires. Some states
require that tires be split (Florida requires at least eight pieces) and other states
require that tires be shredded before landfilling. The State of Ohio is considering tire
monofills and monocells for shredded tires. As a practical matter, whole tires often
are charged high fees at landfills, because operators find them difficult to handle.
Therefore, even in states where landfilling of whole tires is allowed, the practice has
been decreasing.
Advantages of regulations on landfilling tires are that they can make tire
material easier to handle at landfills. These regulations also may discourage
landfilling. This could spur the state and industry to develop and improve means
of using waste tires, such as retreading, recycling, and tires-to-energy alternatives.
However, if these alternate means do not become available soon enough, this may
result in illegal dumping, or an increase in the export of tires to other states. It is,
therefore, important not to restrict tire management options prematurely before
there is adequate source reduction and utilization capacity.
OTHER REGULATORY AND NON-REGULATORY OPTIONS
Following are additional regulatory and non-regulatory options which have been
suggested to help mitigate the scrap tire problem. Some of these have been
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implemented and others are merely ideas under consideration by some tire or solid
waste management experts from government or industry. The following topics are
discussed below: (1) procurement strategies; (2) research; (3) grants and loans; (4)
additional coordination among states; (5) education and promotion; (6) waste
exchanges; (7) tradeable credits; and (8) tax incentives.
Procurement Strategies
The Resource, Conservation, and Recovery Act of 1976 (RCRA) mandated
that EPA prepare guidelines for the purchase of retreaded tires for federal agencies
and for agencies using Federal funds to procure supplies. The final rule was issued
November 17, 1988 and became effective November 17, 1989. Since then the U.S.
General Services Administration (GSA) has developed specifications for retreaded
tires and has developed protocols for testing tires. Of 365 contract awards for
supplying tires to the Federal government, 70 went to retread tire manufacturers.
On February 20,1986, EPA proposed procurement guidelines for scrap rubber
usage in asphalt; however, they were not made final because many state highway
departments believed that not enough research had been completed at that point to
justify promotion of this technology nationally through procurement guidelines.
Procurement guidelines for materials such as rubberized asphalt, products
made from reprocessed rubber, and rubber railroad crossings are all potential means
of helping to encourage these uses of scrap tires.
Research
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.
Both the Federal Highway Administration, and in the 1970s, the EPA, have
funded research on the use of rubber in pavements. Many states' highway
departments have also funded research. A five-year research project, the Strategic
Highway Research Program, is addressing the use of additives such as rubber from
tires, in asphalt. This is a joint effort by the National Research Council, the Federal
Highway Administration, and the American Association of State Highway and
Transportation Officials.
Areas which appear ripe for further research include: (1) research on the use
of crumb rubber in plastic and rubber products, (2) research on environmental
emissions from tire incineration, and (3) research on rubberized asphalt.
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Presently DOE is funding Air Products & Chemical Company for the
development of a fluorine surface treatment of tire rubber (crumb rubber) to modify
its adhesion properties. This modified rubber could be used in making polymers
such as polyurethane and epoxies. The tire rubber might also be used in certain
plastics such as polystyrene and PVC, and in rubber products (68).
EPA is currently collecting existing environmental emissions data from
facilities incinerating tires for energy purposes. This information can be compared
to data on emissions from these same facilities when using conventional fuels such
as coal and hog fuel. Several states and industrial facilities have been conducting
test burns of tire-derived fuel, to gather this environmental data.
Research on the use of crumb rubber in asphalt paving needs to be intensified
and brought to a conclusion. Research on newer forms of rubber and asphalt
mixtures, some without patent protection (thus available at lower cost), needs to be
continued. Research on how asphalt-rubber and rubber modified asphalt concrete
can best be recycled should be performed.
Additional Coordination Among States and Localities
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.
Tires tend to migrate to the least expensive use or disposal option.
Neighboring jurisdictions can work together in planning their policies so that there
are consistent economic incentives to send the tires to a location where they can be
utilized, such as to a tire product facility, a tire-to-energy power plant, or a tdf
production facility. This can help ensure the success of the facility. For instance, if
one town has a tires-to-energy power plant, it may be counterproductive for a nearby
city to set up a municipally subsidized landfill with a shredder that will accept tires
at a lower tipping fee. In this case, most of the tires would gravitate toward the
lower tipping fee and be landfilled, rather than go to the power plant to be utilized.
Education and Promotion
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.
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It is particularly difficult to control the dumping of tires in sparsely populated
areas, and special efforts may be needed to recognize the problems before they get
out of hand. Waste tire dumps may be started on abandoned land and may
accumulate thousands of tires before authorities become aware and are able to take
action. Informed citizens and local police may be particularly helpful in spotting
nascent illegal tire dumps.
Citizens can be educated regarding source reduction alternatives such as
caring properly for tires and using retread tires. Both governments and companies
operating fleets of vehicles can be encouraged similarly. Federal procurement
guidelines for retreaded tires, described above, address this issue.
Tire dealers need ready access to information on reputable or licensed
haulers, recyclers, or disposers of waste tires. They also need information on
companies that sell used tires and that retread tires. Information on the location of
large tire piles is helpful to entrepreneurs seeking to process these tires for eventual
recycling or energy recovery.
Suppliers of scrap tire-derived products often need to educate themselves on
the requirements of potential users of their products. For example, facilities that can
use tire-derived fuel may need this fuel supplied with uniform, consistent quality.
Producers and users of tdf need to work together to classify this material based on
factors such as size of chips and quality of the cut. (i.e., Are there wires protruding
from the rubber chips or is it clean-cut?) This information will help potential users
be assured of quality supplies that will not damage equipment. This information in
turn, aids in developing and expanding markets for tire-derived material.
Information on all potential uses of tires for recycled products and for fuel
should be widely distributed. Dissemination of available data regarding
environmental controls and emissions is also helpful in ensuring that industrial
users of scrap tires implement environmentally sound practices.
Education and promotion may take several forms. Newsletters, fact sheets,
hotlines and conferences on scrap tires can provide the most current formation on
such topics as regulatory developments or new processes for utilizing tires.
Computerized data bases, and clearinghouses, whether operated by government or
by trade groups, are also helpful. These means of communicating are particularly
important for scrap tires, as this field, like much of recycling, is changing quickly.
Reports and studies can provide either broad overviews or more in-depth coverage
of specific tire-related topics.
Waste Exchanges
Another means to aid recycling of tires and the utilization of tires as fuel is to
expand the use of existing solid waste exchanges to include tires. Classified
advertisements in magazines and newsletters can help those who have sources of
-------
tires to find users of tires. Appendix C provides a partial list of newsletters and
magazines that may contain advertisements helpful to entrepreneurs dealing with
scrap tires.
Tradeable Credits
Congress has been considering numerous pieces of legislation that pertain to
the management of municipal solid waste. Some of these focus particularly on
scrap tires. One innovative approach under discussion is a credit system.
Manufacturers would only be allowed to produce a new tire if a given number of
tires were recycled, processed, and/or burned for energy recovery.
Credits would be allocated as follows. One quarter credit could be granted for
shredding one tire, or for burning a shredded tire. One-half credit could be granted
for burning a whole tire. Three-fourths credit could be granted for reusing or
recycling a shredded tire. Finally, one credit could be granted for reusing or recycling
one whole tire (69). The Federal government would work with state governments
to administer this program.
Tax Incentives
Tax incentives were utilized as part of the financing package to build the
Modesto tires-to-energy power plant. Tax-free municipal bonds were issued to
borrow money from investors to build the plant. Utilizing tax-free municipal bonds
allowed borrowing the money at a lower interest rate.
Entrepreneurs are clearly responsive to tax incentives in building a major
waste tire processing facility such as this one. If a state or local government deemed
it especially desirable to site such a facility they could enact legislation to award
appropriate tax breaks.
The utility buy-back rates paid to tires-to-energy facilities have an effect
similar to tax incentives. The difference is that the money ultimately comes from
the utility customers rather than the tax payers. No state has yet attempted to use
state funding to subsidize tires-to-energy plants.
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Chapter 4
CONCLUSIONS
Each year over 240 million tires are scrapped. Current trends indicate that
about 6 percent of these tires are being recycled as products and 11 percent used as
fuel. About 5 percent are exported. The rest are being landfilled, stockpiled, or
dumped illegally.
The primary concern is to reduce the number of tires in uncontrolled
stockpiles or illegal dumps. These tires are often sites of mosquito infestation, with
the potential for spreading dangerous mosquito-borne diseases. Large tire dumps
can also lead to fires with major releases of air pollution and hazardous organic
chemicals into surface and groundwater.
Recycling rubber from tires for use in asphalt pavements is a promising
technology. Asphalt pavements with rubber added are claimed to have twice the
lifetime of ordinary asphalt, but they can cost twice as much. Pavements with
crumb rubber additives consume over one million tires per year now, and both
asphalt-rubber and rubber modified asphalt concrete have considerable potential for
expansion. If Federal, state, and local governments promote much broader
demonstration and use of this technology, perhaps the technical issues will be
resolved and usage will expand.
Using whole tires as fuel for reciprocating grate power plants appears to be
economically feasible in some situations and can meet environmental permitting
requirements. One such plant in Modesto, California, is currently consuming 4.9
million tires per year. Another power plant is under construction in Connecticut
and is expected to consume an additional 10 million tires per year. A second 10
million tire per year plant is being considered for an area near Las Vegas, Nevada.
The main barriers to such plants appear to be local resistance to incineration projects
and lengthy permitting procedures.
The replacement of coal by tire-derived-fuel appears economically feasible for
cement kilns. Seven such kilns are currently operating in the U.S., consuming the
equivalent of about 6 million tires per year between them. There is potential for
this use to expand further, particularly for those cement kilns whose feed systems
are compatible with the use of TDF.
Tire-derived fuel is economically feasible for use in hog fuel boilers in the
pulp and paper industry. It is estimated that the equivalent of 12 million tires is
consumed annually in this way in the U.S. There is potential for this use to expand
further.
91
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Other technologies and options are promising on a smaller scale, but also are
important to the overall solution. Uses of crumb rubber for such diverse products
as athletic surfaces, tracks, and garbage cans show potential for growth. Also,
increased retreading could utilize about 20 million additional passenger and light
truck tires each year, thus delaying their disposal. Current trends, however, indicate
fewer of these tires are retreaded each year.
Other uses of tires can be important in certain geographic areas. Each year,
Cape May County, New Jersey uses about 100,000 tires, which is 100 percent of its
scrap tires, for artificial reefs. The State of Minnesota has used about a million of its
scrap tires since 1986 for roads in swampy areas.
The markets for most other products made from tires have potential, but
appear to be relatively small. These include rubber railroad crossings, artificial reefs,
playground equipment, erosion control, highway crash barriers, playground gravel
substitute, sludge composting, rubber parts for agricultural and fishing equipment,
and rubber mats. Each of these products has the potential for using some portion of
our waste tire stockpile. Collectively, they are all important parts of the solution to
the tire problem.
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REFERENCES
1. U.S. Environmental Protection Agency, Office of Solid Waste. The Solid
Waste Dilemma: An Agenda for Action. February 1989.
2. Demos, E.K., Ph.D. and T.A. Sladek, Ph.D. Disposal Techniques with Energy
Recovery for Scrapped Tires. Urban Consortium Energy Task Force. June
1987.
3. Hope, M.W. Scrap Tire Analysis for Minnesota. Waste Recovery, Inc.
October 1985.
4. Phone conversation with Bill Vincent. Texas Tire Disposal, Fort Worth,
Texas. 1989.
5. Telephone Conversation with Jack Zimmer, Goodyear. Akron, Ohio. 1989.
6. Bob Stuber. Quality Used Tires. Paradise, California. Scrap Tire Processing
and Recycling Conference. San Francisco, California. May 1989.
7. American Retreaders' Association. Letter from Ed Wagner, July 1989 and
phone conversation, November 1990.
8. Telephone conversation with shredding companies. 1989. Shredding costs
vary depending on the fineness of the product.
9. Telephone conversation with T.Y.R.E.S., Inc. August 1989.
10. Annual NSWMA Survey. Waste Age. March 1989.
11. Telephone conversations with industry representatives in each region.
12. Scrap Tire News, Publication by Resource Recycling Research, Inc., Vol. 5, No.
1, January 1991.
13. News Breaks. Waste Age. May 1989.
14. Telephone conversation with Dave Lester. Topper Industries. July 1989.
15. Telephone conversation with Steve Childers. Ocean County, New Jersey.
July 1989.
93
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16. Urban Systems Research and Engineering, Inc. Status, Trends, and
Impediments to Discarded Tire Collection and Resource Recovery. April 23,
1989.
17. Telephone conversation with Diana Crispin. Oregon Department of
Environmental Quality. July 1989.
18. Telephone conversation with William Weisz. Tire Playground, Inc. July
1989.
19. Telephone conversation with John Williams. California Transportation
Laboratory. August 1989.
20. Sladek, Thomas. Disposal Techniques with Energy Recovery for Scrapped
Vehicle Tires. City and County of Denver. 1987.
21. Telephone conversation with Ronald G. Nutting, President, OMNI Rubber
Products. July 1989.
22. Phone conversation with Tim Baker. Baker Rubber Co. and F'resident of
Asphalt Rubber Producers Group. August 1989.
23. U.S. Department of Commerce. Current Industrial Reports. MA30A(89)-1.
June 1991.
24. Phone conversation with Dave Benke. Minnesota Pollution Control Agency.
August 1989.
25. University of Minnesota, Duluth. Center for Economic Development.
Alternative Courses of Action with Regard to Tirecycle Project. For the St.
Louis County Attorney. May 1989.
26. Letter from Mike Harrington, President, PaveTech Corporation, April 1990.
27. Telephone conversation with Tom Van Bramer. New York State
Department of Transportation. July 1989.
28. Schnormeier, Russel, H., P.E. Recycling Tires Into Pavement.
January/February 1988.
29. Telephone conversation with Russel Schnormeier. Asphalt Rubber
Producers Group. July 1989.
30. Telephone conversation with Monte Niemi. First State Tire Disposal. July
1989.
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31. Letter from Russel Schnormeier, Asphalt Rubber Producers Group (ARPG),
April 1990 and telephone conversation with Gary Cooper, ARPG, June 1991.
32. Alaska Department of Transportation. Asphalt Pavements Modified with
Coarse Rubber Particles, Design, Construction, and Ice Control Observations.
August 1984.
33. Chamberlain, W.P. and Prasantu K. Gupta. Use of Scrap Automobile Tire
Rubber in Highway Construction. New York State Department of
Transportation. May 1986.
34. Telephone conversation with Joe Hannon. California Department of
Transportation. July 1989.
35. Telephone conversation with Jeff Smith. International Surfacing, Inc. July
1989.
36. Doty, Robert N. Flexible Pavement Rehabilitation Using Asphalt-Rubber
Combinations. California Department of Transportation. Presentation to the
Transportation Research Board. January 1988.
37. Takallou, H.B., R.G. Hicks, and S.C. Esch. Effect of Mix Ingredients on the
Behavior of Rubber-Modified Asphalt Mixtures. State of Alaska, Department
of Transportation. November 1985.
38. Minnesota Pollution Control Agency. Waste Tires in Sub-Grade Road Beds.
February 19,1990.
39. Telephone conversation with Charlotte Allred. Safety Soil. August 1989.
40. Telephone conversation with George Gramada. Windsor West End Waste
Water Treatment Plan. August 1989.
41. Telephone conversation with Joel Alpert. E&A Environmental Consultants.
Stoughton, Massachusetts. August 1989.
42. Hershey, Dr. Robert L., et al. Waste Tire Utilization. U.S. Department of
Energy. April 1987.
43. The Oxford Energy Company -1988 Annual Report. April 1989.
44. Oxford Energy Gains Final Permit Approval for Connecticut Tire-to-Energy
Project. Oxford Energy Press Release. June 1989.
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45. Marker, Dr. Gordon A. Waste Tire to Energy: Comprehensive Resource
Recovery. Third Annual National Symposium on the Incineration of
Industrial Wastes. San Diego, California. March 1989.
46. U.S. Environmental Protection Agency, Office of Emergency Response.
Municipal Waste Combustion Study: Report to Congress. EPA/530-SW-87-
021. June 1987.
47. Modesto Energy Company Waste Tire to Energy Facility, Westley, California -
Final Emission Test Report. Radian Corporation Report No. 243-047-20.
April 1988.
48. Telephone conversations with Dr. Gordon Marker. Oxford Energy Company.
July 1989.
49. Oxford Energy Press Release, Santa Rosa, California. December 1989.
50. Oxford Energy Announced Development Plans in Lackawaniia, New York.
Oxford Energy Press Release. July 1989.
51. Scrap Tires for Cement Kilns. Exchange Meeting Summary. U.S. Department
of Energy, Office of Industrial Programs. October 1984.
52. Market and Economic Research. The Portland Cement Association. June
1988.
53. Siemering, William H. The Use of Tire Derived Fuel - The Calaveras Cement
Experience. Institute of Electrical and Electronic Engineers, West Coast
Subcommittee, Cement Industry Committee. November 1988.
54. Telephone conversation with Dave Bittle, Arizona Portland Cement, June
1991.
55. Plant visit and interview with Robert Bauer, Controller, Southwestern
Portland Cement Co. November 1989.
56. Telephone conversations with Mark Hope. Waste Recovery, Inc. July 1989
and January 1991.
57. Drabeck, John and Willenberg, Jay. Measurement of Polynuclear Aromatic
Hydrocarbons and Metals from Burning Tire Chips for Supplementary Fuel.
1987 TAPPI Environmental Conference. Portland, Oregon. April 1987.
58. Results of the October 28-30,1987 Criteria and Non-Criteria Emission
Compliance Testing on the Unit 3 Stack at the Champion International
Facility Located in Sartell, Minnesota. Pace Laboratories, Inc. November 1987.
96
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59. Rossman, David R. Emissions Test Reports Prepared for Smurfit Newsprint.
Newburg, Oregon. Horizon Engineering. March-July 1987.
60. Dodds, J. et al. Scrap Tires: A Resource and Technology Evaluation of Tire
Pyrolysis and Other Selected Alternate Technologies. U.S. Department of
Energy - Idaho Operations Center. Report EGG-2241. November 1983.
61. Hunter, Marie. Innovations. Pollution Engineering. October 1989.
62. Second Annual Legislative Update 1990: A Resource Guide to Scrap Tire
Legislative Information in the Fifty States. Scrap Tire News. Recycling
Research, Inc.
63. Minnesota Pollution Control Agency. Tire Tracks. Volume 2, No. 3.
August/September 1990.
64. Minnesota Pollution Control Agency. Fact Sheet #5.
65. Telephone conversation with Deanna Mueller-Crispin. State of Oregon.
December 1990.
66. Telephone conversation with Dorothy Adams. State of Utah. December 1990.
67. Scrap Tire News, Volume 4, No. 3. May/June 1990. Recycling Research, Inc.
68. Integrated Waste Management. McGraw Hill, 1221 Avenue of the Americas,
36th Floor, New York, NY 10020. June 27,1990.
69. Scrap Tire News. Volume 4, No. 2. March/April 1990. Recycling Research,
Inc.
97
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Appendix A
EPA REGIONAL OFFICES
EPA Regions
Region 1
U.S. EPA - Region 1
J.F.K. Federal Building
Boston, Massachusetts 02203
Telephone: 617-565-3715
Region 2
U.S. EPA - Region 2
26 Federal Plaza
New York, New York 10278
Telephone: 212-264-2657
Region 3
U.S. EPA - Region 3
841 Chestnut Street
Philadelphia, Pennsylvania 19107
Telephone: 215-597-9800
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Region 4
U.S. EPA - Region 4
345 Courtland Street, NE
Atlanta, Georgia 30365
Telephone: 404-347-4727
Region 5
U.S. EPA - Region 5
230 South Dearborn Street
Chicago, Illinois 60604
Telephone: 312-353-2000
Region 6
U.S. EPA - Region 6
First Interstate Bank Tower
1445 Ross Avenue
Dallas, Texas 75270-2733
Telephone: 214-655-6444
Region 7
U.S. EPA - Region 7
726 Minnesota Avenue
Kansas City, Kansas 66101
Telephone: 913-551-7000
Region 8
U.S. EPA - Region 8
Denver Place (811WM-RI)
999 18th Street, Suite 500
Denver, Colorado 80202-2405
Telephone: 303-293-1603
Region 9
U.S. EPA - Region 9
1235 Mission Street
San Francisco, California 94105
Telephone: 415-556-6322
Region 10
U.S. EPA - Region 10
1200 Sixth Avenue
Seattle, Washington 98101
Telephone: 206-442-1200
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Appendix B
STATE CONTACTS FOR WASTE TIRE PROGRAMS
ALABAMA
Jack Honeycut
Alabama Department of Environmental Management
Solid Waste Section
1751 Congressman W.L. Dickinson Drive
Montgomery, Alabama 36130
Telephone: 205-271-7761
ALASKA
Glen Miller
Alaska Department of Environmental Conservation
P.O. Box O
Juneau, Alaska 99811-1800
Telephone: 907-465-2671
ARIZONA
Barry Abbott
Arizona Department of Environmental Quality
Office of Solid Waste Programs
2005 North Central
Phoenix, Arizona 85004
Telephone: 602-257-2176
ARKANSAS
Tom Boston
Arkansas Department of Pollution Control and Ecology
Solid Waste Division
P.O. Box 9583
Little Rock, Arkansas 72209
Telephone: 501-570-2858
CALIFORNIA
Bob Boughton
California Waste Management Board
1020 Ninth Street, Suite 300
Sacramento, California 95814
Telephone: 916-322-2674
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COLORADO
Pamela Harley
Colorado Department of Health
Hazardous Materials and Waste Management Division
4210 East llth Avenue
Denver, Colorado 80220
Telephone: 303-331-4875
CONNECTICUT
David Nash
Connecticut Department of Environmental Protection
Solid Waste Management Division
165 Capital Avenue
Hartford, Connecticut 06106
Telephone: 203-566-5847
DELAWARE
Richard Folmsbee
Delaware Department of Natural Resources and
Environmental Control
Division of Air and Waste Management
P.O. Box 1401
Dover, Delaware 19903
Telephone: 302-739-3820
DISTRICT OF COLUMBIA
Joe O'Donnel
Recycling Department
2750 South Capitol St., SW
Washington, DC 20032
Telephone: 202-767-8512
FLORIDA
Bill Parker
Department of Environmental Regulation
Office of Solid Waste - Twin Towers Office Building
2600 Blair Stone Road
Tallahassee, Florida 32399-2400
Telephone: 904-922-6104
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GEORGIA
Charles Evans
Georgia Department of Natural Resources
Industrial and Hazardous Waste Management Program
3420 Norman Berry Drive - 7th Floor
Hapeville, Georgia 30354
Telephone: 404-656-2836
HAWAII
AlDurg
Department of Health and Environmental Quality
Solid and Hazardous Waste
5 Waterfront Plaza - Suite 250
Honolulu, Hawaii 96813
Telephone: 808-543-8243
IDAHO
Jerome Jankowski
Department of Health and Welfare
Division of Environmental Quality
Hazardous Materials Bureau
1410 North Hilton
Boise, Idaho 83706
Telephone: 208-334-5879
ILLINOIS
Chris Burger
Dept. of Environment and Natural Resources
325 West Adams - Room 300
Springfield, Illinois 62704-1892
Telephone: 217-524-5454
INDIANA
Timothy Holtz
Department of Environmental Management
Solid and Hazardous Waste Management
105 South Meridian Street
Indianapolis, Indiana 46225
Telephone: 317-232-7155
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IOWA
Teresa Hay
Iowa Department of Natural Resources
Waste Management Authority
900 East Grand Avenue
Henry A. Wallace Building
Des Moines, Iowa 50319-0034
Telephone: 515-281-8941
KANSAS
Ashok Sunderraj
Kansas Department of Health and Environment
Bureau of Waste Management
Forbes Field
Topeka, Kansas 66620
Telephone: 913-296-1595
KENTUCKY
Charles Peters
Department of Environmental Protection
Division of Waste Management
18 Reilly Road
Frankfort, Kentucky 40601
Telephone: 502-564-6716
Randy Johann
Kentuckian Regional Planning and Development
11520 Commonwealth Drive
Louisville, Kentucky 40299
Telephone: 502-266-6084
LOUISIANA
Butch Stegall
Louisiana Department of Environmental Quality
Office of Solid and Hazardous Waste
P.O. Box 44066
Baton Rouge, Louisiana 70804-4066
Telephone: 504-342-9445
MAINE
General: Cliff Eliason; Enforcement: Terry McGovern
Department of Environmental Protection
Bureau of Solid Waste and Management
State House, Station 17
Augusta, Maine 04333
Telephone: 207-582-8740
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Jody Harris
Recycling: Maine Waste Management Agency
Office of Waste Recycling & Reduction
State House Station No. 154
Augusta, Maine 04333
Telephone: 207-289-5300
MARYLAND
Muhamud Masood
Department of the Environment
Hazardous and Solid Waste Management Administration
2500 Broening Highway, Building 40
Baltimore, Maryland 21224
Telephone: 301-631-3315
MASSACHUSETTS
Jim Roberts
Department of Environmental Quality
Division of Solid Waste
1 Winter Street, 4th Floor
Boston, Massachusetts 02108
Telephone: 617-292-5964
MICHIGAN
Kyle Cruse
Department of Natural Resources
Resource Recovery Section
P.O. Box 30241
Lansing, Michigan 48909
Telephone: 517-373-4738
MINNESOTA
Tom Newman
Pollution Control Specialist
Minnesota Pollution Control Agency
Waste Tire Management Unit
520 Lafayette Road
St. Paul, Minnesota 55155
Telephone: 612-296-7170
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MISSISSIPPI
Bill Lee
Department of Environmental Quality
Office of Pollution Control
Division of Solid Waste Management
P.O. Box 10385
Jackson, Mississippi 39209
Telephone: 601-961-5171
MISSOURI
Jim Hull
Department of Natural Resources
Waste Management Program
P.O. Box 176
Jefferson City, Missouri 65102
Telephone: 314-751-3176
MONTANA
Tony Grover
Department of Health and Environmental Sciences
Solid and Hazardous Waste Bureau
Room B-201, Cogswell Building
Helena, Montana 59620
Telephone: 406-444-2821
NEBRASKA
Dannie Dearing
Department of Environmental Control
Land Quality Division
P.O. Box 98922
Lincoln, Nebraska 68509-8922
Telephone: 402-471-4210
NEVADA
John West
Division of Environmental Protection
Bureau of Waste Management
123 West Nye Lane - Capitol Complex
Carson City, Nevada 89710
Telephone: 702-687-5872
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NEW HAMPSHIRE
William Evans
New Hampshire Department of Environmental Services
Waste Management Division
6 Hazen Drive
Concord, New Hampshire 03301
Telephone: 603-271-3713
NEW JERSEY
Joe Carpenter
Recycling Division
Department of Environmental Protection
Division of Solid Waste Management
850 Bear Tavern Road, CN 414
Trenton, New Jersey 08625-0414
Telephone: 609-530-4001
NEW MEXICO
Marilyn G. Brown
Health and Environmental Department
Solid and Hazardous Waste Management Program
1190 St. Francis Drive
Santa Fe, New Mexico 87503
Telephone: 505-827-2892
NEW YORK
Ben Pierson
Division of Solid Waste
Department of Environmental Conservation
50 Wolf Road
Albany, New York 12233
Telephone: 518-457-7337
NORTH CAROLINA
Jim Coffey, Dee Eggers (technical assistance)
Department of Environment, Health, and Natural Resources
Solid Waste Management Division, Solid Waste Section
P.O. Box 27687
Raleigh, North Carolina 27611-7687
Telephone: 919-733-0692
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NORTH DAKOTA
Steve Tillotson
State Department of Health
Division of Waste Management & Special Studies
P.O. Box 5520
Bismarck, North Dakota 58502-5520
Telephone: 701-224-2366
OHIO
Natalie Farber
Ohio Environmental Protection Agency
Division of Solid & Hazardous Waste Management
1800 Watermark Drive
Columbus, Ohio 43266-0149
Telephone: 614-644-2917
OKLAHOMA
Kelly Dixon
Oklahoma State Department of Health
Waste Management Service
P.O. Box 53551
Oklahoma City, Oklahoma 73152
Telephone: 405-271-7159
OREGON
Deanna Mueller-Crispin
Department of Environmental Quality
Hazardous & Solid Waste Division
811 SW Sixth
Portland, Oregon 97204
Telephone: 503-229-5808
PENNSYLVANIA
Jay Ort
Department of Environmental Resources
Bureau of Waste Management
P.O. Box 2063, Fulton Building
Harrisburg, Pennsylvania 17105-2063
Telephone: 717-787-1749
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RHODE ISLAND
Victor Bell
Office of Environmental Coordination
83 Park Street
Providence, Rhode Island 02903
Telephone: 401-277-3434
Adam Marks
Central Landfill
65 Shun Pike
Johnson, Rhode Island 02919
Telephone: 401-942-1430
SOUTH CAROLINA
John Ohlandt
Charleston County Health Department
334 Calhoun Street
Charleston, South Carolina 29401
Telephone: 803-724-5970
SOUTH DAKOTA
Terry Keller
Department of Water and Natural Resources
Office of Solid Waste
Room 222, Foss Building
523 East Capital
Pierre, South Dakota 57501
Telephone: 605-773-3153
TENNESSEE
Frank Victory
Department of Health and Environment
Division of Solid Waste Management
Customs House, 4th Floor
701 Broadway
Nashville, Tennessee 37247-3530
Telephone: 615-741-3424
TEXAS
L.D. Hancock
Department of Health
Permits & Registration Division
Division of Solid Waste Management
1100 West 49th Street
Austin, Texas 78756-3199
Telephone: 512-458-7271
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Donald O'Connor
Texas State Department of Highways and
Public Transportation
Materials and Testing Division
125 East llth Street
Austin, Texas 78701
Telephone: 512-465-7352
UTAH
Dorothy Adams
Salt Lake City County Health Department
Sanitation & Safety Bureau
610 South 200 East
Salt Lake City, Utah 84111
Telephone: 801-534-4526
VERMONT
Eldon Morrison
Agency of Natural Resources
Department of Environmental Conservation
Waste Management Division
103 South Main Street, Laundry Building
Waterbury, Vermont 05676
Telephone: 802-244-7831
VIRGINIA
R. Allan Lassiter, Jr.
Division of Recycling & Litter Control
Department of Waste Management
101 North 14th Street
James Monroe Building, llth Floor
Richmond, Virginia 23219
Telephone: 804-786-8679
WASHINGTON
Dale Clark
Department of Ecology
Solid and Hazardous Waste Management Program
Mail Stop PV-11
Olympia, Washington 98504-8711
Telephone: 206-459-6258
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WEST VIRGINIA
Paul Benedun
Department of Natural Resources
Division of Waste Management
1456 Hansford Street
Charleston, West Virginia 25301
Telephone: 304-348-6350
WISCONSIN
Paul Koziar
Department of Natural Resources
Bureau of Solid & Hazardous Waste Management
101 South Webster Street
Madison, Wisconsin 53707
Telephone: 608-267-9388
WYOMING
Timothy Link
Department of Environmental Quality
Solid Waste Management Program
122 West 25th Street
Herschler Building, 4th Floor
Cheyenne, Wyoming 82002
Telephone: 307-777-7752
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Appendix C
ADDITIONAL SOURCES OF INFORMATION ON SCRAP TIRES
Newsletters and Magazines
Grain Communications, Inc.
Rubber and Plastic News
1725 Merriman Road, Suite 300
Akron, Ohio 44313
Telephone: 216-836-9180
Grain Communications, Inc.
Tire Business
1725 Merriman Road, Suite 300
Akron, Ohio 44313
Telephone: 216-836-9180
National Solid Wastes Management Association
Recycling Times
1730 Rhode Island Avenue, NW - Suite 1000
Washington, DC 20036
Telephone: 202-861-0708
National Solid Wastes Management Association
Waste Age
1730 Rhode Island Avenue, NW - Suite 1000
Washington, DC 20036
Telephone: 202-861-0708
National Tire Dealers & Retreaders Association, Inc.
Dealer News
Suite 400, 1250 "I" Street, N.W.
Washington, D.C. 20005-3989
Telephone: 202-789-2300, 800-87N-TDRA
Old House Journal Corp.
Garbage
435 Ninth Street
Brooklyn, New York 11315
Telephone: 718-788-1700
Recycling Research Institute
Scrap Tire News
133 Mountain Road
Suffield, Connecticut 06078
Telephone: 203-668-5422
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Resource Recycling, Inc.
Resource Recycling
1218 NW 21st Street
Portland, Oregon 97210
Telephone: 503-227-1319
Trade Associations
American Retreaders1 Association, Inc.
P.O. Box 17203
Louisville, Kentucky 40217
Telephone: 502-367-9133
Asphalt Rubber Producer's Group
3336 North 32nd St. - Suite 106
Phoenix, Arizona 85018
Telephone: 602-955-1141
National Asphalt Paving Association
5100 Forbes Boulevard
Lanham, Maryland 20706-4413
National Tire Dealers and Retreader's Association
1250 I Street, NW
Washington, DC 20005
Telephone: 202-789-2300
Rubber Manufacturer's Association '
1400 K Street, NW
Washington, DC 20005
Telephone: 202-682-4800
Scrap Tire Management Council
1400 K Street, NW
Washington, DC 20005
Telephone: 202-408-7783
Tire Retread Information Bureau
P.O. Box 374
Pebble Beach, California 93953
Telephone: 408-625-3247
United States Government
Federal Highway Administration
400 7th Street, SW
Washington, DC 20590
Telephone: 202-366-0660
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RCRA Information Center
Office of Solid Waste (OS-305)
U.S. Environmental Protection Agency
401 M Street, SW
Washington, DC 20460
RCRA/Superfund Hotline
Telephone: 800-424-9346
Small Business Administration
1441 L St., NW
Washington, DC 20416
Telephone: 202-653-6567
U.S. Department of Energy
1000 Independence Avenue, SW
Washington, DC 20585
Telephone: 202-586-5000
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