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Scrap Tire Disposal and Recycling Options. Presentation to the Border Environment Cooperation Commission by the Houston Advanced Research Center December 2003. Agenda. Scrap tire overview Human health and environmental effects Scrap tire stockpiles Open-air tire incineration
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Scrap Tire Disposal and Recycling Options Presentation to the Border Environment Cooperation Commission by the Houston Advanced Research Center December 2003
Agenda • Scrap tire overview • Human health and environmental effects • Scrap tire stockpiles • Open-air tire incineration • Controlled tire incineration • U.S. regulatory framework • Mexican regulatory framework • The BECC certification criteria and tire disposal and recycling projects
Scrap tire generation • In the United States, about 280 million scrap tires are generated per year (one per person) • In Mexico, about 40 million scrap tires are generated per year • Many more used tires are imported into Mexico, both legally and illegally, contributing extensively to the scrap tire problem
Tire-derived fuel (cont.) • Most developed market for scrap tires worldwide • Depending on the incinerator and primary fuel, tires can be burned whole or shredded • Used as a supplemental fuel with solid fuels such as coal or wood • Used predominantly by the cement industry, also by power plants, pulp & paper mills, and steel mills • Emissions profile is similar to coal’s, but with more particulate matter and zinc and less SO2 41% of scrap tires generated in the U.S. in 2001 were used as fuel
Civil engineering applications • Structural backfill • Erosion control • Landfill liners and covers • Municipal sewage treatment • Septic system drainage fields
Civil engineering applications (cont.) • Leaching from the metal in the tire chips is a concern • Formation of “hot spots” in tire shreds used in fill projects is a concern • ASTM standards have been developed to manage these concerns 14% of scrap tires generated in the U.S. in 2001 were used in civil engineering projects
Ground rubber applications • Rubber-modified asphalt • Playgrounds and athletic surfaces • Molded & bound products • Livestock mats • Speed bumps • Railroad crossings • Roof shingles • New tire manufacturing 12% of scrap tires generated in U.S. in 2001 were recycled into ground rubber
Ground rubber applications (cont.) Rubber-modified asphalt • Largest use of ground rubber—12 million tires/yr • Withstands hot and cold temperatures better than traditional asphalt • Lower life-cycle costs • AZ study found 40% lower life-cycle cost over 25 years • Increased traffic safety due to increased skid resistance and decreased maintenance needs • Decreased traffic noise by 4-6 decibels
Other uses for scrap tires • Retreading (for tire casings in good condition) • Pyrolysis • 40% carbon black • 25% pyrolysis oil • 20% hydrocarbon gases • 15% steel • Gasification • H2, CO, CH4 and CO2 (Hydrogen economy potential) • 2004 DOE demonstration project of mobile gasification-to-power unit in El Paso/Juárez area
Financial viability • Viability of any tire disposal or recycling project is highly dependent on several project-specific factors • Supply — # of locally available scrap tires • Location — Distance of tire stockpiles from the recycling center, and distance from markets for the end product • Size of system — economies of scale • Labor — costs of transporting, handling, and processing the tires • Condition — tires that have been in stockpiles may be too dirty or degraded for some options • Fuel costs — for TDF, cost of competing fuels such as coal and natural gas
Health effects • Tires provide habitat for vectors of human disease • Mosquitoes • Yellow fever, dengue fever, malaria, encephalitis and the West Nile virus • Rodents • Rabies, hantavirus, lyme disease, and the plague • Transport of tires spreads invasive species • Asian tiger mosquito (Aedes albopictus) • Yellow Fever mosquito (Aedes aegypti )
Contaminants of concern include: • Aluminum • Barium • Chromium • Iron • Lead • Manganese • Zinc • Volatile organic compounds (VOCs) • Semi-volatile organic compounds (SVOCs) Scrap tire pile hazards: Contaminant leaching Contaminants can leach (in absence of fire) to: • Surface water • Ground water • Soil
Scrap tire pile hazards: Fire • Highly combustible • Ignition by arson or lightning strikes • 20 major tire fires annually in the U.S. • Costly and lengthy firefighting efforts; substantial clean up problems • Sources of environmental contamination • Air • Surface water and ground water • Soils
Human health effects of open tire fires • Nearby residents • Emergency responders • Acute and chronic health effects • Irritation to skin, eyes, and mucous membranes • Respiratory effects • Central nervous system depression • Cancer
Air emissions from open burning of tires • Pose acute and chronic threats to health of nearby residents • 16 times more toxic than residential wood combustion • 16,000 times more toxic than coal-fired utility emissions • Contain Criteria Pollutants: Carbon monoxide (CO), particulate matter (PM), nitrogen dioxide (NOx), and sulfur dioxide (SO2) • Contain Hazardous Air Pollutants (HAPs): Benzene, dioxins/furans, hydrogen chloride, polynuclear aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) • Contain other compounds: Arsenic, cadmium, chromium, mercury, nickel, vanadium, zinc, and additional volatile organic compounds (VOCs)
Air emissions from tire-derived fuel (TDF) • TDF often used as 10-20% supplement to traditional solid fuels (coal, wood, and coke) • TDF produces slightly less CO2 than municipal solid waste, wood, and coal • TDF pollutants of concern include: • Zinc • Three times higher with TDF than with natural gas • Several orders of magnitude greater than other metals • Total particulate matter • Trace amounts of dioxins/furans • Emissions may increase during periods of startup, shutdown, and equipment malfunction
TDF emissions research • Data describing emissions from older or poorly operated TDF facilities are lacking • Research is continuously evolving • Many technical considerations under the Clean Air Act are under development • Testing protocols and emissions standards have not been developed for all potential emissions
Human health effects of TDF emissions • Contaminants with greatest potential to do harm: • Zinc • Inhalation in dust or fumes • Acute Immune System impacts - “Metal Flume Fever” • Chronic effects unknown • Particulate matter • PM10 and PM2.5 can become lodged in the lungs • Dioxins and furans • Highly toxic to humans • Trace amounts can cause irreparable harm
Particulate Matter • The EPA has identified health effects associated with particulate matter as including: • Premature death, acute respiratory symptoms, asthma, chronic bronchitis, decreased lung function/shortness of breath, and straining of the heart. • The health effects of particulate matter inhalation may not be immediately noticed and can be exacerbated by continuous exposure. • Toxic compounds such as heavy metals can bind to particulates and enter the blood stream and affect other organs such as the liver or kidneys.
Dioxins and Furans Two closely related classes of chemicals • Highly persistent in the environment, extremely toxic, known human carcinogens • Not intentionally manufactured; are a byproduct of the combustion of chlorinated compounds. Exposure can result in: • Chloracne; liver damage; changes in glucose metabolism; changes in hormone levels; weakening of the immune system; weight loss; nervous system disorders; reproductive damage; and birth defects Trace amounts in the air emissions could enter the food chain • Contamination of downwind food crops and livestock pastures Build up in fatty tissue • Accumulate substantially up the food chain • Found in human breast milk
Risk management and minimization • Public participation • Fire prevention planning and training • Emergency control strategies • Use of best available technologies for the combustion system to ensure efficient and complete combustion of TDF • Use of best available technologies for the control system to ensure complete entrapment of particulate matter and metal emissions • Fabric filters • Electrostatic precipitators • Baseline testing and trial burns • Regular monitoring of emissions of compounds recognized as a priority for TDF ambient air quality monitoring • Unannounced site visits and monitoring to ensure compliance and to build public confidence
International framework • Canada, Sweden, Finland, and South Korea are leaders in tire disposal • EU landfill directive eliminates whole scrap tires from landfills by 2003, all scrap tires from landfills by 2006 • U.S. – Mexico Border Environmental Relations • La Paz Agreement; IBEP; Border XXI; Border 2012 • Attempts to harmonize environmental issues along border • State initiatives • BECC initiatives
History of U.S. tire regulation • Evolved from public recognition of problem in 1980’s • Winchester tire fire • Little federal regulation exists • Scrap tires are classified as solid waste • Managed by states • Transport, landfill, storage, and incineration permits / restrictions • Manifest programs • Fees • Subsidies for recycling and end use options • Financial assurance • Aspects of tire disposal and incineration are subject to federal regulation • SWDA, RCRA, CAA
Mexican environmental regulations • Ley General de Equilibrio Ecológico y Protección al Ambiente (LGEEPA) • Defines hazardous wastes • Sets policy goals • Outlines obligations of federal government • LGEEPA has been revised many times • Permitting and enforcement agency • SEMARNAT
Scrap tire regulation in Mexico • Incineration has been federally regulated since 2002; disposal and storage are managed by states • Norma Oficial Mexicana NOM-040-ECOL-2002, Protección Ambiental-Fabricación de Cemento Hidráulico – Niveles Máximos Permisibles de Emisión a la Atmósfera • Current use in kilns • Illegal burning of alternative fuels throughout the country • Ley General para la Prevención y Gestión Integral de los Residuos • Passed in October 2003, requires waste management plans for significant waste streams, including tires • State regulations • Current efforts • New Norma to help states manage tire jurisdiction
Emissions monitoring for cement kilns using alternative fuels
General Certification Criteria • Tire-to-energy, civil engineering, and ground rubber projects would all meet goal of solid waste reduction • Tire-to-energy as well as gasification would also meet key objective of creating a waste-to-energy project • Emissions controls for particulate matter and zinc may be required at a tire-to-energy facility to comply with U.S. and Mexican laws
Human Health & Environment Certification Criteria • Tire-to-energy projects could comply with this criteria • Do tire-to-energy projects offer the “high” level of protection required? • A tire-to-energy project may have cross-border impacts and require an additional environmental assessment • Civil engineering projects would rate high in this category, although leaching and “hot spots” must be guarded against • Ground rubber applications would rate very high in this category
Technical Feasibility Certification Criteria • Some stockpiled tires may not be usable for many processed tire applications, particularly ground rubber projects • Supply of tires may challenge the requirement for adequate resource inputs • Training of locally available labor should be included in project plans
Financial Feasibility Certification Criteria • Tire-to-energy projects are currently the most economic • Civil engineering projects can also be financially viable • Ground rubber projects could be financially viable, but initially may require public grants or subsidies Financial feasibility is highly dependent on tire supply, system location, energy prices, and labor and operating costs
Community Participation Certification Criteria • Tire-to-energy projects may be met with considerable public skepticism • Civil engineering and ground rubber projects would generate less public concern • Transparency of the project plan and sponsor communications is critical • At public forums, alternative solutions as well as the “no action” alternative should be discussed • Instituting a public comment period for proposed scrap tire projects would facilitate participation
Sustainable Development Certification Criteria Sustainability rankings: • Retreaded tires • Civil engineering applications • Ground rubber applications • Whole tire incineration • Shredded TDF incineration • Landfilling shredded tires • Landfilling whole tires • Gasification • Pyrolysis
Overarching themes • Critical tire management strategy—to eliminate scrap tire piles • Fire prevention planning and training is paramount for existing tire stockpiles • All options discussed (tire-to-energy, civil engineering, ground rubber) have the potential to be certified under the BECC criteria • If economically feasible, civil engineering and ground rubber projects would be the most socially and environmentally sustainable