Materials Characterization Paper In Support of the Final Rulemaking:
Identification of Nonhazardous Seco ndary Materials That Are Solid Waste
Auto Shredder Residue

February 3, 2011

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1. Definition of Auto Shredder Residue

Auto shredder residue (ASR) is the 20 – 25 percent of vehicle mate rials remaining after a vehicle has been shredded and removed of reusable part s and metals. ASR is composed of plastics, rubber, foam, residual metal pieces, paper, fabr ic, glass, sand, and dirt (EPA, 2008; USCAR, 2008; Nourreddine, 2007). It is also termed “auto fluff” or “auto shredder fluff.”

2. Annual Quantities of Auto Shredder Residue Generated and Used

(1) Sectors that generate auto shredder residue Auto shredding operations, categor ized under NAICS 423930 (Recyclable Material Merchant Wholesalers) are th e only known generators of ASR. There are approximately 185 to 200 auto sh redders in the U.S. (Boughton, 2006; DeGaspari, 1999).

(2) Quantities of auto sh redder residue generated The U.S. generates approximately 5 milli on tons of ASR annually and nearly all of this is landfilled (Hook, 2008; EPA, 2008).

(3) Trends in generation of auto shredder residue Quantities of ASR produced are likely to increase in the future, due to the growing number of cars scrapped each year and the increased us e of plastics in automobile production (Nourreddine, 2007).

3. Uses of Auto Shredder Residue

(1) Combustion uses of auto shredder residue Currently, nearly all ASR is landfilled and a small portion is incinerated, primarily owing to the lack of cost-e ffective technology to process and use ASR (Argonne, 2003). An additional barrier to us ing it as fuel is that unprocessed ASR has high ash, heavy metal, and chlorine content (Boughton, 2006).

Approximately 20 to 50 percent of dry ASR is combustible, including plastics, fabric, and rubber; incombus tibles include metals, glass, dirt, and ash. The first step in processing ASR for fuel use w ould be removal of incombustibles (Tai, 2006; Boughton, 2006).Auto Shredder Residue

2 ASR could potentially be used as a s upplement to conventional fuel in cement

kilns or steel mill blast furnaces. Use of ASR in cement kilns may be more easily accomplished than in boilers and other combustion units because kilns can tolerate high ash content and heterogene ous materials. A recent evaluation of ASR use in cement kilns conducted by th e California Department of Toxic Substances Control suggests that, despit e the obstacles of se parating combustibles from incombustibles and reducing contam inant concentrations, processing ASR for use in cement kilns would be cost-effective, due largely to the avoided transportation costs and tipping fees a ssociated with landfilling (Boughton, 2006). This effect, however, would vary throughout the U.S. due to regional differences in transportation distances and landfill tipping fees. In addition, the Environment and Plastics Industry Council and the American Plastics Council have conducted research investigating methods to process ASR into a more suitable fuel for steel mill blast furnaces (Cirko, 1999).

(2) Non-combustion uses of auto shredder residue As mentioned above, nearly all ASR is la ndfilled, and it appear s that virtually no ASR is currently beneficially used . 40 CFR 761.62, “Disposal of PCB bulk product waste,” states, however, that ASR may be disposed in landfills as daily cover or used under asphalt as part of ro ad bed, but no data on such applications have been identified. In addition, ot her potentially recoverable materials

contained in ASR and thei r potential uses include:

• Foam, which accounts for 5 percent of vehicles by weig ht but 30 percent by volume, can be rebounded and used as carpet padding an d seat cushions in cars (DeGaspari, 1999).

• Plastics, which account for 30 percent of vehicle weight, can be recycled into battery trays (Hook, 2008) and pot entially other products (Wagger, 2010).

• The finer residuals (<250 μ m) can be used as ingredients in cement production (Argonne, 2003) and co mposites (Nourreddine, 2007).

(3) Quantity of auto shredder residue landfilled Sources generally state that most, if not all, ASR is landfilled (Hook, 2008; EPA, 2008; Boughton, 2006). This would suggest that approximately 5 million tons of ASR are landfilled annually.

4. Management and Combustion Processes

(1) Types of units using auto shredder residue Currently most ASR is landfilled, though de velopment of methods to use ASR is underway. Potential users of ASR include:

• Cement kilnsAuto Shredder Residue

3 • Steel mill blast furnaces

• Car manufacturers

(2) Sourcing of auto shredder residue Approximately 12 to 15 million automobiles are disposed of annually in the U.S. (USCAR, 2008). Once automobiles reach th e end of their useful life, they are sent to one of roughly 12,000 auto disman tlers, where the car is stripped of reusable parts. The stripped cars are then sent to one of approximately 185 to 200 auto shredding operations, where hammermills crush them into smaller pieces.

Metal chunks are recovered and sold to metal scrap processing industries (DeGaspari, 1999). Over 25 million tons of materials are recovered for reuse or recycling. The remaining materi al comprises the ASR (EPA, 2008).

(3) Processing of ASR for combustion uses Unprocessed ASR has poor fuel characterist ics, due to its hi gh ash content; the presence of contaminants, including h eavy metals, chlorine, and PCBs; and the heterogeneity of ASR, which is made up of approximately 20 to 50 percent incombustibles (Tai et al, 2006; Boughton, 2006). Prior to use as a fuel, ASR would therefore require significant se paration and processing to isolate

combustible materials with low ash cont ent and low contaminant concentrations.

The California Department of Toxic Subs tances Control has developed methods for separating and beneficiating the ASR stream to make it suitable fuel for cement kilns. First, trommels are used to create ASR sub-streams of different sizes, which also results in some rough se paration by material (e.g., residual metal fines are small, while plastic and rubbe r pieces are larger). Then further separation is performed by hand and thr ough density separation techniques, with the goal of developing a mi xture of ASR that maximizes energy content, while minimizing content of ash, chlorine, and heavy metals. This process achieves a mixture of ASR that represents 30 per cent of the original mixture and has a heating value of approximately 13,240 Btu per pound, which is higher than that of most types of coal (Boughton, 2006).

The Environment and Plastics Industry Council and the American Plastics Council coordinated with eight automobile shredders to develop a procedure for processing ASR for use in steel mill blast furnaces. This process, which would

reduce the ash content of ASR and increa se its energy content, would yield an

ASR material with a thermal valu e of approximately 10,000 Btu per pound (Cirko, 1999).

Researchers in Taiwan have taken furthe r steps in the development of ASR for fuel use by processing it into ASR-derived fuel (ASRDF) rods, for ease of transportation and storage. The first step in this process is the manual removal of glass, electrical wires, di rt and gravel, and metal co mponents, yielding an ASR mixture with a heat value of approximately 10,500 Btu/pound. Then the ASR is placed into an extrusion apparatus, wher e it is exposed to high pressure andAuto Shredder Residue

4 temperature and formed into rods. The extrusion process reduces the heat value by approximately 1,800 Btu/pound, but the ro ds have a higher heat per unit of mass than does the un-compacted material (Tai et al, 2006).

(4) Processing of ASR for non-combustion uses As indicated above, virtually no ASR is used for non-combustion applications because of the heterogeneity of ASR ma terial. The Department of Energy’s Argonne National Laboratory, however, has recently developed methods for separation, recovery, and use of ASR. After undergoing separation and cleaning processes, certain constituent materials of ASR can be recovered. Argonne has found that up to 60 percent of ASR can be recovered as usable material (Hook, 2008).

The process developed by Argonne begins with bulk separation through use of a two-part trommel, which separates ASR into three streams: a polymersconcentrated stream (45 percent of ASR, by weight), foam (10 percent), and small inorganic particles (45 percen t). The first part of the trommel is equipped with a fine mesh, through which the inorganic pa rticles are separated. The second part of the trommel has larger slots, through which plastics and rubber pieces fall, leaving behind the foam. Each of these th ree streams is then further processed to extract the useful materials. The pol ymers undergo density separation and frothflotation to be separated by type, in order to recover those plastics and rubbers that are present in the largest volumes or that have the highest value. The foam,

which contains automotive fluids and some residual inorganic particles, is run through a series of stages for cleaning, and is then dried and baled. The inorganic particles, which include metal residuals, di rt, and glass, are e xposed to magnets to extract iron oxides, and the rest is discarded (Argonne, 2003; DeGaspari, 1999)

At present, Argonne’s system is not yet used in the United States, though it has been licensed to Salyp N.V., a recycler in Belgium, which completed construction of an ASR recycling plant in 2003 (DeGaspari, 1999; Hook, 2008).

(5) State regulatory status of auto shredder residue beneficial use According to state respons es to a 2006 survey by the Association of State and Territorial Solid Waste Management Officials (ASTSWMO), Florida has approved ASR as landfill initial cover, while Kentucky, Maryland, Massachusetts, Michigan, New Hampshire, New York, Te nnessee, Virginia, and Wisconsin have approved it as an alternate daily landf ill cover. ASTSWMO also reports that Michigan and Texas have approved ASR fo r liquid solidification. Wisconsin has pre-approved ASR for landfilling and Washington has pre-approved ASR in a few cases as alternative daily cover (ASTSWMO, 2007).Auto Shredder Residue

5 5. Commodity Composition and Impacts

(1) Composition and energy content of auto shredder residue (a) Composition: The physical composition of auto shre dder residue is unc ertain given the heterogeneous nature of this material. For example, data from Hook (2008) and DeGaspari (1999) suggest that the material composition of ASR is as

follows:

 30 percent polymers (by weight)

 10 percent residual metals

 5 percent foam

 The remainder is a mixture of glass, wood, paper, sand, dirt, rocks, and

automotive fluids.

The more detailed composition a ssessment from Nourreddine (2007) presented in Table 1 suggests, however , that metals make up approximately 30 percent of ASR, nearly three times the amount suggested by the data from Hook (2008) and DeGaspari (1999).

(b) Energy content:

 Unprocessed ASR – roughly 5,000 Btu/pound (Boughton, 2006)

 After removal of incombustibles – 9,000-10,500 Btu/pound (Tai et al, 2006; Cirko, 1999)

 After removal of incombustibles and additional processing to isolate combustibles with high energy content - 13,240 Btu/pound (Boughton, 2006)Auto Shredder Residue

6 Table 1: Physical and Chemic al Characteristics of ASR

Constituent ASR 1

by weight

Carbon ppm 495,000 Hydrogen ppm 53,000 Oxygen ppm 69,000 Nitrogen ppm 45,000

Sulfur ppm 2,000 Carbon Dioxide ppm

- Methane ppm

- Ethane ppm

- Propane ppm

- Butane ppm

- Volatile Matter ppm 541,800
Chlorine ppm 5,000 Fluorine ppm 500 Phosphorous ppm 7,000 Chromium ppm 800

Copper ppm 12,000

Zinc ppm 19,000 Nickel ppm 700 Lead ppm 2,000 Silicon ppm 21,000

Iron ppm 257,000 Titanium ppm 9,000

Water ppm 22,000
Mercury ppm - 1. Nourreddine (2007)

(2) Impacts of auto shredder residue use

a. Cost impacts The recycling and use of ASR may resu lt in cost savings. The California Department of Toxic Substances Contro l conducted an economic analysis of ASR use in cement kilns, and found that th e processing and use of all annuallygenerated ASR for cement kilns would sa ve the cement manuf acturing industry $50 million per year through reduced energy costs. It would also save auto shredding operations $20 million per year in avoided landfilling costs. While the costs of processing the ASR for use in cement kilns would also amount to $20 million per year, auto shredding operations could also generate $20 million per year in revenue from the sale of coppe r, which is extracted during processing (Boughton, 2006). Alternatively, if all ASR were to be used as a fuel in steel mill blast furnaces, it could reduce fuel costs for operators by as much as $20 per ton of coke replaced (Cirko, 1999). 1

1 The figures presented in this paragraph could change over time, owing to variations in virgin fuel prices, landfilling costs, and the value of copper. The California Department of Toxic Substances Control assumed the following prices and values: a price of $50/ton of coal, landfilling tipping fee of $17/ton, trucking cost of $2/mile, average distance to landfill of 20 miles, and $0.85/pound value of scrap copper wiring.Auto Shredder Residue

7 Regarding the use of ASR for non-fuel a pplications, savings could be achieved through avoided production of virgin foam. While clean recycled foam sells for $0.25 to $0.30 per pound, virgin foam costs approximately $1 per pound (Argonne, “Recovering Foam from Scrapped Autos”). In addition, the savings referenced above with respect to copper recovered from ASR prior to its use as a fuel would presumably apply to beneficial use for non-fuel applications as well. Savings could also be realized through th e re-use of other materials contained in ASR, but no information on these savings has been identified.

b. Environmental impacts Comprehensive data on the environmental impacts of using ASR as a substitute for virgin materials have not been iden tified. Available data sources, however, contain the following informati on regarding these impacts:

• Argonne estimates that the recovery and reuse of polymers and residual metals, for non-fuel applications, from all of the ASR pr oduced annually in the United States would save the equivalent of 24 million barrels of oil per year and reduce CO 2 emissions by 12 million tons (Hook, 2008). 2

• Benefits from the use of ASR as a fuel may also include reduced CO 2 emissions from substitution for coal (Boughton, 2006). The California Department of Toxic Substances Contro l estimates that if all ASR produced in the United States were processe d for use in cement kilns, it could potentially provide 6 percent of th e cement industry’s energy needs and result in the conservation of approximately one million tons of coal annually.

• Additionally, diverting ASR from la ndfills prevents potential leachate contaminated with ASR constituents (Boughton, 2006).

It is important to note that the presence of contaminants in ASR raises concerns

about emissions from the combustion of th is material. The California Department

of Toxic Substances Control found that , while its processing techniques for developing ASR as a fuel for cement kiln s minimizes contaminant concentrations, chlorine and heavy metals still remain at levels that may limit the rate at which ASR may be fed into a cement kiln (Boughton, 2006). Additionally, although ASRDF rods have low heavy metals concentrations, the chlorine content of these rods may represent a potential hazard (Tai et al, 2006). 3 Additional efforts to eliminate PVC from ASR prior to its co mbustion for fuel purposes may mitigate

2 It is unclear whether these figures represent estimates of direct or lifecycle energy and emissions impacts. In addition, it is unclear whether this CO 2 emissions value is net of the emissions associated with burning ASR.

3 In the Taiwanese study, no efforts were taken to remove combustibles with high chlorine contents, so

chlorine contamination is more of a concern than in the Ca lifornia study. Yet, in the Taiwanese study, metals were removed more thoroughly by hand, so the rods present less of a threat of metal concentrations.Auto Shredder Residue

8 chlorine-related contamination issues, gi ven that PVC is t ypically 50 percent chlorine (Boughton, 2006).Auto Shredder Residue

9 References

Argonne. 2003. “Materials Recovery from Auto Shredder Residue.” <http://www.es.anl.gov/Energy_systems/Proces s_Engineering/Technologies/Documents/ 3-ASR_2003.pdf>.

Argonne. “Recovering Foam from Scrapped Autos.” Argonne National Laboratory <http://www.anl.gov/techtransfer/Available_Te chnologies/Environmental_Research/auto

shredder.html>.

Association of State and Terri torial Solid Waste Management Officials (ASTSWMO). 2007, 2006 Beneficial Use Study Report , published by Association of State and Territorial Solid Waste Management Officials.

Boughton, Robert. 2006. “Evaluatio n of shredder residue as cement manufacturing feedstock.” California Department of Toxic Substances Control.

Cirko, Cathy. 1999. “Auto shredder residue pote ntial fuel for steel mill blast furnaces.”

Canadian Chemical News , September 1, 1999.

DeGaspari, John. 1999. “From trash to cash: A ne w process reclaims former unrecoverables in the residue of scrapped vehicles.” Mechanical Engineering Magazine Online <http://www.memagazine.org/backissues/m embersonly/june99/features/trash/

trash.html>.

Hook, Brian R. 2008. “Auto shredder residue recycling researched.” AmericanRecycler.com <http://www.americanrecycler.com/1008/auto.shtml>.

Nourreddine, Menad. 2007. “Recycli ng of auto shredder residue.” Journal of Hazardous

Materials 139(3): 481-490.

Tai, Hua-Shan, Sheng-Cheng Chang, and Wan-Sh an Su. 2006. “Investigation of the Derived

Fuel Rod Formation from Auto Shredder Re sidue Using an Extrusion Apparatus.” Environmental Progress 25(3): 235-252.

United States Council for Automotive Research LLC (USCAR). 2008. “Did you know that cars are the most recycled product in Am erica?” Press Release of USCAR <http://www.uscar.org/guest/article_view.php?articles_id=192>.

United States Environmental Protection Agen cy (EPA). 2008. “Automotive Parts,” at Common
Wastes & Materials <http://www.epa.gov/epawaste/c onserve/materials/auto.htm>.

United States Environmental Protection Agency (EPA), 2010. Preliminary Characterization Study: Traditional Fuels and Key Derivatives, Prepared in Support of the Final Rulemaking – Identification of Nonhazardous Secondary Materials That Are Solid

Waste. Docket Number EPA-HQ-RCRA-2008-0329. December 2010.Auto Shredder Residue

10 Wagger, David L, public comment in response to EPA’s Proposed Rulemaking for Identification

of Non-Hazardous Materials That Are SolidWaste, EPA docket/document number EPAHQ-RCRA-2008-0329-1186, submitted on behalf of the Institute of Scrap Recycling Industries, August, 3, 2010.