RECYCLABILITY INDEX FOR AUTOMOBILES
A Thesis presented
to the Faculty of
California Polytechnic State University
In Partial Fulfillment
of the Requirements for the Degree
Master of Science in Civil and Environmental Engineering
AUTHORIZATION FOR REPRODUCTION OF MASTER’S THESIS
I hereby grant permission for the reproduction of this thesis in its entirety or any of its
parts, without further authorization, provided acknowledgement is made to the author and
TITLE: AUTOMOBILE RECYCLABILITY INDEX FOR AUTOMOBILES
AUTHOR: ALEXANDER TSUJI
DATE SUBMITTED: JUNE 2006
__________________________________________________ Date:_____________ Dr. Yarrow Nelson, Advisor and Committee Chair __________________________________________________ Date:______________ Dr. Samuel A. Vigil, Committee Member __________________________________________________ Date:______________ Dr. Andrew Kean, Committee Member
Recyclability Index for Automobiles
by Alexander Tsuji
A rating system was developed to quantify the environmental impacts of light-
duty motor vehicles at the end of their life-cycle based on recyclability, toxic material
content and ultimate disposal. About 4.5 to 5 million tons of vehicle material is disposed
in U.S. solid waste landfills annually. Increasing recyclability of automobiles could
reduce this loading to landfills and reduce resource consumption. The rating system
developed here could be used to educate consumers about environmental performance
and allow them to factor this performance into their choice of automobiles. The score of
this rating system could be posted on new vehicle stickers and on the EPA website,
similar to the fuel efficiency value. This is expected to influence the vehicle
manufacturers' choices of design and manufacturing methods by providing a voluntary
incentive for increasing recyclability and reducing the use of toxic materials of their cars.
This would be a pollution prevention similar to the Toxic Release Inventory helps reduce
the amount of hazardous waste produced.
The end-of-life vehicle (ELV) rating system, modeled after life cycle assessment,
has two parts: one based on recyclability and one based on toxicity. The recyclability
portion of the scoring was adapted after the ISO 22628 standard, while the percent
subtraction of heavy metals was an original idea. The recyclability portion is based on the
content of ferrous and non-ferrous metal content (which is 100% recyclable) and the
plastics for which there is a market for recycling. The toxicity index is based on the
content of lead (excluding batteries, which are recycled), mercury, cadmium and
hexavalent chromium. The toxicity index subtracts from the recyclability portion of the
rating score in order to give the final rating for an automobile. This rating system was
tested on a generic 1995 vehicle. The generic vehicle received a final end-of-life rating of
a C+ on a traditional A to F grading metric. Due to the recyclability, the vehicle got a B
rating (82.6%); however, the toxicity rating subtracted 6.6%, giving the final rating of C+
(76.0%). The numerical rating of 76% does not reflect the actual recyclability percentage
of the automobile. The actual recyclability of the automobile is still the original 82.6%.
The critical barrier to this project was obtaining manufacturer data on automobiles.
Unfortunately, such information is often proprietary and not in the public domain. In
order to implement this rating system, comprehensive material listings are needed from
manufacturers, possibly mandated by the EPA.
Future work could be used to further develop the recyclability index through work
consisting of 3 parts: Peer review of the existing model, model refinements, and
development of an implementation strategy. The peer review would provide feedback
from industry professionals about the feasibility and technical soundness of the work up
to now. This could be accomplished using a number of different sources including
professional associations, automobile manufacturers, and other industry professionals.
Then the model could be refined in response to the addressed concerns from the peer
review. Some of the key elements that would be required for implementation are EPA
agency approval, enforcement of proper vehicle recycling procedures, data acquisition,
and a quality control procedure.
The author would like to thank the EPA P3 program for the funding of this
project. Also, I would like to thank the following Cal Poly professors for their input: Dr.
Yarrow Nelson, Dr. Andrew Kean, Dr. Sam Vigil, Dr. Hal Cota, Dr. Linda Vanasupa,
Prof. Margot McDonald, and Dr. Deanna Richards. Also I would like to thank the
following for their assistance: Automotive Recyclers Association, Japan Auto Recyclers
Association, State of California Auto Dismantlers Association, Institute of Scrap
Recyclers Industries, the Steel Recycling Institute, Automotive Recyclers of Canada,
Yasuhiko Ogushi, Dr. Xavier Swamikannu, Richard Paul, Martha Cowell, Phillip and
Larry Ball, and the attendees of the International Automobile Recyclers Congress.
Finally, the author would like to thank all his friends, family, and fellow environmental
engineering colleagues (graduate and undergraduate) for making him remember that the
thesis was important but was not everything in life.
TABLE OF CONTENTS
List of Tables......................................................................................................ix
List of Figures .....................................................................................................x
Chapter 1: Introduction ......................................................................................1
Chapter 2: Background ......................................................................................3
Automobile Recycling Process in the United States .......................................................... 3
Global legislation ................................................................................................................ 7
Chapter 3: ELV rating system............................................................................9
Recyclability Score ............................................................................................................. 9
Toxicity Score ................................................................................................................... 13
Grading System................................................................................................................ 22
Recyclability Index for Test Case ..................................................................................... 23
Chapter 4: Discussion ......................................................................................28
Reusable Parts ................................................................................................................. 28
Consumer Education ........................................................................................................ 29
Sensitivity Analysis ........................................................................................................... 31
System Updating .............................................................................................................. 32
Recyclable Plastics........................................................................................................... 33
Design for the Environment/Disassembly ........................................................................ 34
Automobile Recycling Yard Practice ................................................................................ 36
Manufacturer Information ................................................................................................. 37
Comparison to Other Rating Systems.............................................................................. 38
The Development Process ............................................................................................... 41
Chapter 5: Future Research.............................................................................43
Peer Review of the Existing Model................................................................................... 43
Model Refinements........................................................................................................... 45
Implementation ................................................................................................................. 46
Measurable Results.......................................................................................................... 47
Chapter 6: Conclusions....................................................................................48
List of References.............................................................................................50
I. Class Lecture Notes ...................................................................................................... 61
II. Handout ........................................................................................................................ 68
III. Homework.................................................................................................................... 70
IV. Homework Solutions ................................................................................................... 72
V. Test Questions ............................................................................................................. 75
VI. Test Question Solutions .............................................................................................. 78
LIST OF TABLES
Table 1. ELV Parts and Use (Keoleian, 2001)……………………………………... 4
Table 2. Shredded Material Components (Keoleian, 2001) ………………………. 5
Table 3. ASR Components (Keoleian, 2001)……………………………………… 5
Table 4: Summary of the Toxic Materials in an Automobile: Applications and
Health Impacts……………………………………………………………………... 13
Table 5: Typical Quantities of Toxic Metals in an Automobile…………………… 14
Table 6: Lead Content of ASR (Gearhart 2003)…………………………………… 16
Table 7: Toxic Equivalent Potential scores of heavy metals……………………..... 20
Table 8: Average Heavy Metal Non-cancer and Cancer Risk ….…………………. 20
Table 9: Average Heavy Metal Percent Subtraction for Toxicity Rating…………. 21
Table 10: Rating System Grading………………………….. ….…………………. 23
Table 11: 1995 Model Year Generic US Family Sedan Material Categories and
Specific Materials (Sullivan 1998)………………………………………………… 24
Table 12: Percent Subtraction for the Case Study…………………………………. 27
Table 13: Case Study Rating ……………………………………………………….27
Table 14: Hazardous Material Use Exemptions in Europe (Beckett, 2005)……….. 40
Table 15: Proposed Phase II Project Schedule…………………………………….. 47
LIST OF FIGURES
Figure 1: ELV Recycling and Disposal Process Flow Diagram………………..….. 4
Figure 2: Lead Content of Automobiles (Gearhart, 2003)…………………………. 15
Figure 3: Percent Metal Mass for Various Automobiles…………………………... 32
CHAPTER 1: INTRODUCTION
The world population depends on automobiles with about 700 million cars, trucks
and other vehicles currently in use worldwide (EPA, 2004). Each year in the United
States, 10-11 million vehicles are retired from service because of major component
failure, structural integrity loss due to extended normal wear, corrosion or accidents
(Environmental Defense, 1999). Currently, about 75% of the vehicle mass is recycled in
the United States (Bandivadekar, 2004). The remaining non-recoverable material is called
automotive shredder residue (ASR) and mainly consists of the non-metallic materials
(e.g. plastics, glass, carpeting). 4.5 to 5 million tons of ASR are generated each year in
the United States and land-filled across the country (Keoleian, 2001). The resource-
consumption and waste-management problems created by ASR are likely to grow as
vehicle manufactures continue to use more plastics, fibers, and composites to reduce
weight and increase fuel efficiency (Environmental Defense, 1999). Plastics are the
fastest growing component of waste at the automobile’s end-of-life (Griffith, 2005).
Currently, plastics make up about 9% of the vehicle weight. This percentage is up from
0.6% of the vehicle weight in 1960. By 2020, the automotive plastics industry wants to
establish plastics as the material of choice in many automotive components and systems
design because of the lightweight nature of plastics (Foster, 2004). In addition to
designing for light weight and fuel efficiency, it is also important to improve automobile
design to reduce the volume and weight of ASR. An important problem with ASR is that
it is considered a hazardous waste in the state of California if there are significant
amounts of toxic contaminants (Barclay, 2006) making it more difficult and expensive to
Instead of relying on regulation, we set out to design a tool which would allow market
forces to implement similar improvements in the United States. Recently, both Europe
and Japan have implemented legislation mandating automobile recycling rates of 85% by
2006 and 95% by 2015 (Europa, 2005) (Togawa, 2005)+. This paper describes a rating
system that quantifies the ecological impacts of end-of-life vehicles (ELVs) by taking
into account recyclability, toxic material content, and disposal. A case study was
performed in order to show the mechanisms of the rating system. The rating system is
designed to educate consumers about the end-of-life impact of the cars they are planning
to purchase. By educating consumers about end-of-life vehicle impacts of their
automobiles, hopefully they will convert this knowledge into action and purchase
automobiles that are more environmentally friendly. Currently, consumers can see
information such as the fuel efficiency on the new vehicle sticker or the EPA website
(EPA, 2006). Similarly, the score from this ELV rating system could be placed on this
same sticker and added to the EPA website. As consumers begin to purchase more
environmentally friendly automobiles, manufacturers will focus on supplying this need at
least to improve corporate image.
CHAPTER 2: BACKGROUND
Automobile Recycling Process in the United States
Typical steps in processing an End-of-Life Vehicle (ELV) are shown in the flow
diagram in Figure 1. First, the ELV is dismantled at a recycling yard (e.g. high-value
parts dismantler or salvage yard). At this yard, mandatory removed materials and
reusable parts are removed from the ELV. Mandatory removed materials consist of tires,
the battery, and fluids. These materials are mainly removed due to regulation. Reusable
parts consist of body panels, the engine, transmission, etc (listed in Table 1). The parts
are removed mainly due to market demand. For example, the starter for a Toyota Corolla
would be removed, while the starter for a Ford Escort would not. Through experience, the
recycling yards understand which parts are profitable to remove from each vehicle. Many
yards only accept automobiles depending on the parts which can be sold for profit (Ball,
2006). After the vehicle is dismantled, the remaining hulks (consisting of steel frame,
foam seats, plastic dashboard, and other components) are flattened, and shipped to a
Automotive Hulk Shredder
Figure 1: ELV Recycling and Disposal Process Flow Diagram
Table 1. ELV Parts and Use (Keoleian, 2001) Type Useclutch, water pump, engine, starter,alternator, transmissionwheels, body panels repair accident damaged vehiclesaluminum/copper parts sold to nonferrous processorsgasoline recover for useantifreeze, windshield cleaning fluid recycleair conditioning and refrigerant gases recover for use or destructionlead acid battery recycle
tires burn for energy recover, landfill, or stockpile
catalytic converters recover for precious metalair bags reuse/dispose
recycle steellandfill plastic
remanufacture and sell for reuse
After shredding, the hulk becomes fist-sized pieces consisting of the components
in Table 2. The ferrous material (steel and iron) is magnetically separated from the non-
ferrous material (metal and non-metal) and is sent to a steel smelter that specializes in
processing steel scrap. The non-ferrous material is sent to a separation facility that
recovers the non-ferrous metal (brass, bronze, copper, lead, magnesium, nickel, and
Mandatory Removed Materials
Reusable Parts (body
Residue (plastic, glass)
(steel frame, foam seats)
stainless steel). What remains is the automotive shredder residue (ASR), the typical make
up of which is shown in Table 3. In the U.S., this is sent to landfills for disposal
Table 2. Shredded Material Components (Keoleian, 2001)
Type Examples Percent weight
ferrous metals iron, steel 65 to 70non-ferrous metals
aluminum, stainless steel, copper, brass, lead, magnesium, zinc, nickel 5 to 10
ASR plastic, glass, rubber, foam, carpet, textile 20 to 25
Table 3. ASR Components (Keoleian, 2001)
Type PercentPlastic 31Rubber 8Glass 12Other material (carpet, textiles) 13Dirt, metal fines 20moisture 15
There are many programs helping automobile recyclers to meet the business,
licensing, and environmental standards of the industry. For example, the State of
California Auto Dismantlers Association sponsors a Partners in the Solution® program.
This industry-led initiative motivates facility mangers to perform better while complying
with business, safety and environmental regulations. Some examples of environmental
standards of the industry include
• Fluid removal when fluid containing parts are dismantled, or prior to crushing
vehicles. The fluids include fuel, motor oil, transmission fluid, brake fluid,
antifreeze and Freon.
• Recyclable and hazardous materials are stored undercover in appropriately
labeled and secured containers with secondary containment.
• Lead acid batteries are removed from vehicles and stored undercover on an
impervious surface with secondary containment.
• During the wet season (October through May), storm water best management
practices are placed at storm water discharge locations.
Other ‘business-led’ initiatives include the Certified Automotive Recycler (CAR)
and Gold Seal certification programs sponsored by the Automotive Recyclers
Association. The environmental standards of the industry focus on the proper recycling
and disposal of all automotive related hazardous materials including gasoline, oil, Freon,
antifreeze, brake fluid and transmission fluid (State of California, 1999).
Toxic metals such as mercury, cadmium, hexavalent chromium, and lead can be
viewed as impediments to recycling because metals contaminate the contaminate the
metal being recovered for recycling. Also, in California, if any of these metals exceed
specific concentrations in the waste extract of ASR, the ASR will become a hazardous
waste (Barclay, 2006). Also, there is other legislation concerning the strict regulation of
mercury switch removal (Department of Toxic Substances Control, 2004).
This rating system is based on the recycling process as shown in Figure 1 and
modified to include PE and PET plastic removal. The process was chosen as the baseline
recycling process for use in this model based on current California law (Arcaute, 2004),
and recommendations of the State of California Auto Dismantler’s Association (State of
California, 1999). Though this process is chosen as a basis for the rating system, due to
higher demands on certified recyclers, there are a growing number of unlicensed
dismantlers not adhering to environmental regulations (Arbitman, 2003). These
dismantlers are not monitored, therefore environmentally responsible procedures (e.g.
gasoline and antifreeze removal) may not be practiced. Due to these factors, the accuracy
of this rating system is dependent on the effective regulation of auto dismantlers.
Europe and Japan have addressed the impacts of ELVs in recent legislation
focused on the use of toxic materials in the automobile and the recyclability of the
automobile(Togawa, 2005). The European Union (EU) passed a directive mandating
recycling 85% of the automobile weight by 2006 and 95% of the automobile weight by
2015 (Europa, 2005). The European legislation also bans hazardous material use such as
mercury, hexavalent chromium, cadmium, and lead. Since the automobile manufacturer
or importer is held responsible for recycling costs in Europe, the last holder of the ELV
can dispose of the vehicle free of charge. Member states are required to set up ELV
collection systems and implement material coding for proper identification of the
materials during dismantling. Every three years, the member states will report to the
commission on the implementation of the directive (Europa, 2005).
Japanese automakers responded to the European directive for two reasons: the EU
is an important market for Japanese automakers, and the ELV directive has implications
of becoming a global standard. In the beginning of 2005, the Japan Automobile
Recycling Law came into effect focusing on chlorofluorocarbons (CFCs), airbag and
ASR disposal (Togawa, 2005). The goals of the legislation slightly differ from the EU
legislation by focusing on the recycling rates of ASR rather than the total vehicle.
However, the percent weight required to be recycled of the automobile is similar in the
Japanese and EU legislation. The Japanese legislation calls for, by the end of 2005, the
ASR recycling rate to be at 30%, corresponding to a vehicle recycling rate of 88%
(Toyota, 2006). By 2010, the ASR recycling rate must increase to 50% corresponding to
a vehicle recycling rate of 92%. Finally in 2015, the ASR recycling rate is mandated at
70%, which corresponds to a vehicle recycling rate of 95% (Toyota, 2006), which is
similar to that of the EU standard. In contrast to the EU legislation, customers in Japan
will bear the recycling costs by paying a deposit recycling fee when purchasing a new
car, or when their car is inspected or deregistered. The manufacturer will be responsible
for removing and recycling the CFCs, airbags, and ASR (Togawa, 2005). The Japan
Automobile Manufacturers Association will be responsible for enforcing the law (Isuzu,
2004). This law does not ban any hazardous material use; however, there is a voluntary
initiative restricting the use of hazardous materials (Togawa, 2005).
CHAPTER 3: ELV RATING SYSTEM
The rating system is intended to quantify the ecological impacts of end-of-life
vehicles by using a material listing of an automobile. The listing will mainly be used for
the recyclable and toxic materials. The objective is to provide a score that can be
translated to a letter grade based on the automobile’s recyclability and toxic materials
content. This letter grade is based on a numerical score which is found by calculating the
recyclability percent of the automobile, then subtracting a penalty percentage due to the
amount of selected toxic metals. The traditional A to F academic grading system was
used as the final rating the consumer will see.
The recyclability (R) is calculated using Figure 1 with a few modifications, as
described later. The method is similar to that reported by ISO (The International
Organization for Standardization, 2002). The recyclability will be determined by
summing the masses of the recyclable materials and dividing by the ELV weight. The
recyclable mass, for the rating system described in this paper, are mandatory removed
materials (mmrm), reusable parts (mrep), ferrous metals (mf) and non-ferrous metals (mnf).
Thus, the recyclability is calculated as:
= (Eq. 1)
The first term, mmrm, consists of the mass for tires (mt), batteries (mb), and fluids
(mfl), shown as
flbtmrm mmmm ++= (Eq. 2)
The second term, mrep, consists of the mass of reusable parts, such as body panels,
the engine, etc. This term was significantly adjusted due to many reasons. First, the input
of this model was a material listing for an automobile, not a component listing. A
material listing contains the type and mass of each material used in an automobile. A
component list contains the type and mass of each component used in the automobile.
The material list was chosen as an input because it seemed like realistically obtainable
information because of the recent effort by auto manufacturers to create the International
Material Data System, which archives all materials used in an automobile (International,
2006). It seemed very unrealistic for manufacturers to provide the mass of every
component in an automobile. The second reason for not including the mass of reusable
parts is because another system would be needed to predict the reusability of a
component. This system would need to model the used car industry and used car parts
industry. If the automobile can still be driven, the parts will not be removed for resale,
but rather, the complete automobile will be sold as a used car. If the automobile is
undrivable, then the parts would be removed for resale. As stated before, the removed
parts depend on the market, which depends on the geographic location, part condition,
year, and demand. Since modeling the used car industry and used car parts industry is
beyond the scope of this project, the mass of the resellable parts would be distributed
among other variables (mf, mnf), defined by materials. For example, even though the
transmission may be reused, it would be seen in this model as a mass of ferrous and/or
nonferrous metal. If further research is done to model the variable of reusable parts, it
would contribute to making this model more accurate.
The third (mf) and fourth (mnf) terms will not be adjusted. Consequently, they
would represent the mass of ferrous and non-ferrous metal in the automobile.
Another term considered in the automobile’s recyclability is the mass of
recyclable plastic. Currently, glass, elastomers, and plastics are not recycled in the U.S.,
hence, disposed as ASR. However, methods are being developed for recycling the plastic
(Costlow, 2006), so plastics were included as being recycled while glass and elastomers
were not. If methods were developed to recycle the other two materials, their mass could
be considered into the recycled amount in future revisions of the model.
The recyclability is thus calculated as:
= (Eq. 3)
mt = the mass of the tires
mb = the mass of the battery
mfl = the mass of the fluids
mf = the mass of the ferrous metal
mnf = the mass of the nonferrous metal
mrp = the mass of the recyclable plastic
The weight of the recyclable plastic in a vehicle (mrp) is determined by the
npnppppppprp mrmrmrmrm ,,3,3,2,2,1,1, *...*** +++= (Eq. 4)
rp,1 = the recycled marketability of plastic 1. If a plastic has a recycled market value, then
the r value will be 1. If the plastic does not have a recycled market value, the r value will
be 0, and
mp,1 = the mass of plastic 1.
Using Equation 4, the mass of all the ELV plastics with market value are summed
together. If the plastic is theoretically recyclable, but does not have a market, this system
will assume that it is land-filled and not considered as recyclable. This is a valid
assumption because the recycling industry is market driven, so if there is no market value
for a material, it will not be recycled.
The only plastics currently considered to have a market value in 2006 are high
density polyethylene (PE) and polyethylene terephthalate (PET) (American Metal Market
2006). Therefore, for this analysis, equation 4 can be simplified to the following:
petpetpeperp mrmrm ** +=
rpe = 1 for polyethylene plastic (PE),
mpe = the mass of PE,
rpet = 1 for polyethylene terephthalate plastic (PET),
mpet = the mass of PET.
Thus, the final equation for mrp is simplified to:
petperp mmm += (Eq. 5)
Therefore, with all the substitutions, the recyclability score based on the 2006
market for recycled plastic is calculated by the following equation:
= (Eq. 6)
The next part of the rating system takes into consideration the automobile’s toxic
materials, which can be an impediment to recycling. The selected toxic materials for
analysis are shown in Table 4 with their corresponding use in automobiles and their
potential health impacts.
Table 4: Summary of the Toxic Materials in an Automobile: Applications and
Automobile Application Health Impacts
Lead Batteries, wheel balance weights, alloys (Gearhart, 2003)
brain and kidney damage (Gearhart, 2003)
Mercury Switches, lamps (Davis, 2001) brain and nervous system damage (Wisconsin, 2005)
Cadmium Brakepads, circuit boards (Gerrard, 2005) kidney disease (EPA, 2000)
Hexavalent Chromium Surface coating (Graves, 2000) lung cancer (US OSHA, 2000)
Substances of Concern
The four heavy metals (lead, mercury, cadmium, and hexavalent chromium) were
chosen because they are identified as the substances of concern pertaining to automobiles
in Europe and Japan. As described in the Background section, The European Union
passed a directive banning the use of these hazardous materials in automobiles (Europa,
2005). Also, in Japan, there is a voluntary initiative restricting the use of these hazardous
materials (Togawa, 2005). In California, if the ASR exceeds a certain concentration for
these substances of concern, the ASR becomes hazardous waste (Barclay, 2006). The
average quantities of these metals found in an automobile are shown in Table 5. Each
toxic metal is described individually below.
Table 5: Typical Quantities of Toxic Metals in an Automobile
Weight (grams) SourceLead* 500 (Gearhart, 2003)Hexavalent Chromium 16.5 (Preikschat, 2003)Mercury 0.9 (Davis, 2001)Cadmium n/a**
*Batteries not included
**The typical mass of cadmium in an automobile is not available data.
Lead is a toxin with many health impacts such as brain damage and kidney
damage (Gearhart, 2003). Figure 2 shows the average lead content of automobiles.
Including the battery, each car manufactured today contains about 12.2 kilograms of lead
(Gearhart, 2003). The battery contains the most lead in the automobile (96%). Batteries
are effectively recycled (about 90% of all lead acid-batteries are recycled (EPA, 2006)),
thus were not considered in this ELV rating. However, the environmental contamination
from the remaining quantities of lead (4.1% - see Figure 2) is still significant. Lead in
steel alloys and automotive coatings are released to the environment when metals are
recycled. When the automobile is shredded, lead contaminates the entire shredded
product (ferrous, non-ferrous and ASR portions) and contributes to lead emissions to the
environment (Gearhart, 2003). Table 6 below shows the significant amount of lead in
ASR. Lead was thus considered one of the metals of concern in ASR causing the
California Department of Health Services to designate ASR as hazardous waste (EPA,
1991). In California, the ASR is considered hazardous waste when the lead concentration
is over 50 mg/L in the waste extract of the ASR (Barclay, 2006). When the scrap metal
from automobiles is processed by steel smelters, the impurities are removed as slag or
released as dust and gaseous by-products to the environment. The generated slag and dust
are also listed as hazardous waste.
Wheel balance weights1.7%
Zinc coating< 0.1%
Terne metals, brazing<0.1%
Electronics -circuit boards
Figure 2: Lead Content of Automobiles (Gearhart, 2003)
Table 6: Lead Content of ASR (Gearhart 2003)
U.S. CanadaUmweltsbundesamt, Germany (Weiss, 1996) 3,500-7,050 15,825 1,583Environmental Protection Agency, USA (EPA, 1991) 570-12,000 18,855 1,886
Department of Health Services, California (Nieto, 1989) 2,330-4,616 10,419 1,042
Average -- 15,033 1,504
Data sourceLead concentration (mg/kg)
Lead in ASR, Average (metric tons per year)a
a. Based on 3 million metric tons of ASR potentially landfilled each year in the U.S. and 300,000 metric tons in Canada
Hexavalent chromium causes lung cancer and can cause skin ulcers under
prolonged skin contact (US OSHA, 2000). Chromium is used as a coating for automobile
parts due to the characteristics of appearance, durability, and corrosion resistance
(Graves, 2000). The most commonly used method of chrome plating is the traditional
coating system using electroplated zinc followed by hexavalent chromium containing
yellow chromate (Wynn, 2003). In California, the ASR is considered hazardous waste
when it has over 5 mg/L of hexavalent chromium in the waste extract of the ASR
Cadmium is very toxic to humans because it is carcinogenic and can cause kidney
diseases (EPA, 2000). Cadmium is used in the automobile industry for brake pads and
circuit boards (Gerrard, 2005). Cadmium has many favorable features for the automotive
industry such as excellent anti-corrosion properties, lubricity, and good solderability
(Wilson, 1986). In California, the ASR is considered hazardous waste when it has over 1
mg/L of cadmium in the waste extract of the ASR (Barclay, 2006).
Mercury can cause both brain and nervous system damage and it accumulates up
the food chain leading to higher concentrations in top level predators (Wisconsin, 2005).
The California Department of Health Services concluded that mercury is another one of
the metals of concern to classify ASR as hazardous waste (Posselt, 2000). In California,
the ASR is considered hazardous waste when it has over 0.2 mg/L of mercury in the
waste extract of the ASR (Barclay, 2006). Mercury switches are used in convenience
lighting, anti-lock braking systems (ABS), active ride control systems, high intensity
discharge headlamps, and fluorescent lamps (background lighting, speedometers)
(Gearhart, 2004). These mercury switches account for more than 99% of the mercury
used in automobiles, with each switch containing approximately 0.8 grams of mercury
(Davis, 2001). Though the use of mercury in convenience lighting switches has declined
about 70% since 1996, the use in other applications (ABS, high intensity discharge
headlamps, navigation displays, family entertainment systems) is rising. For ABS
applications, it has risen about 160% since 1996 (Davis, 2001).
Most of the mercury in ELVs is released to the environment when the steel
smelters process the recycled scrap metal (Davis 2001). These smelters are the single
largest manufacturing source of mercury air emissions (15.6 metric tons/year) in the US –
larger than all other manufacturing sources combined. It is the 4th largest of all mercury
air emission sources, behind coal-fired utilities, municipal waste incinerators, and
commercial/industrial boilers (Davis, 2001).
The ELVs processed in the United States last year contained a total of nine metric
tons of mercury (Keoleian, 2001). Over the last 30 years, 120 metric tons of mercury has
been released into the environment due to vehicle disposal. An equal amount could be
released over the next two decades if mercury use is not abated or if action to recover the
mercury is not taken (Gearhart, 2004).
Though states such as California have passed legislation concerning mercury
switches, little known recovery of mercury switches during automobile dismantling or
recycling is practiced (Davis, 2001) (Ball, 2006). Beginning January 1, 2005, any vehicle
that contains a mercury light switch in the hood or trunk is considered a hazardous waste
as soon as someone crushes, bales, shreds or shears the vehicle. In most of the cases in
California, crushing a vehicle without removing all mercury light switches will be illegal
(Department of Toxic Substances Control, 2004). However, other mercury switches such
as in dome lights, glove compartment lights and inside ABS systems are not accounted
for in this legislation (Department of Toxic Substances Control, 2005). Currently in
California, dismantlers are responsible for removing mercury switches from ELVs. In
order to compensate such dismantlers for the labor cost of removing such switches, the
State of California Auto Dismantlers Association is working with the Alliance of Auto
Manufactures on a program where the Alliance will pay for the disposal of mercury
switches (Cowell, 2006b). However, when speaking with a recycler of the State of
California Auto Dismantlers Association, he was doubtful that many recyclers are
removing the mercury switches (Ball, 2006).
Toxicity Rating System
In order to compare the heavy metals, toxic equivalency potential (TEP) system
developed by Hertwich and Pease (Scorecard, 2005) was used. The TEP system is
basically a metric, but instead of liters, or inches, it uses pounds of benzene/toluene. For
cancerous risks, the mass of heavy metal is equated to a mass of benzene, and for non-
cancer toxicity, it is equated to a mass of toluene. The reference material amounts are
calculated using the CalTOX model, an environmental fate and exposure system used by
California regulatory agencies (Scorecard, 2005).
So, one kilogram of cadmium is equal to about 12,000 kilograms of benzene
(cancer risk) and 860,000 kilograms of toluene (non-cancer risk). The benzene and
toluene equivalents for one kilogram of all the other toxic metals are shown in Table 7.
However, there is not one kilogram of mercury in an average automobile (See Table 5).
There are only 500 grams. This amount of mercury is equal to 950,000 kilograms of
toluene and 14 kilograms of benzene. Table 8 shows the benzene and toluene equivalents
for the average amount of toxic metal in an automobile. When comparing the benzene
and toluene weights of the toxic metals, a few conclusions can be made. First, lead is the
most toxic out of all the metals. Then, hexavalent chromium has 2 more benzene
kilograms of cancer risk than mercury. But, mercury has about 13,000 more toluene
kilograms of non-cancer risk. When comparing hexavalent chromium and mercury, the
investigator made a decision in viewing both as having the same toxicity.
Table 7: Toxic Equivalent Potential Scores of Heavy Metals (Scorecard, 2005)
Cancer risk score (kilograms of benzene per kilogram of heavy metal)
Noncancer risk score (kilograms of toluene per kilogram of heavy metal)
Cadmium 11,804 862,600Chromium 59 1,090Lead 13 263,320Mercury 0 6,356,000
Table 8: Average Heavy Metal Non-cancer and Cancer Risk
Mass (kilograms) Non-cancer risk (kilograms of toluene)
Cancer Risk (kilograms of benzene)
Lead 0.5 (Gearhart, 2003) 950,000 14Mercury 0.00091 (Davis 2001) 12,700 0Chromium 0.017 (Preikschat, 2003) 41 2Cadmium n/a n/a n/a
Now, the amount of toxic metal in the automobile needed to be equated to a
percent deduction from the recyclability score. A decision was made to make 1% the
deduction when the average amount of toxic metal was present in an automobile. So, if
the automobile had 500 grams of mercury, 1% would be deducted from the score.
However, not all toxic metals had the same toxicity. Due to the high cancer and
noncancer risks of lead relative to the other metals, it was weighted at 2% subtraction
Table 9. Mercury and chromium were given the same weight because, while the mercury
has a significantly higher noncancer risk, chromium has more of a cancer risk. The
difference of noncancer risk (13,000 kilograms of toluene) and the difference of cancer
risk (2 kilograms of benzene) were assumed to be of equal value, so they were weighted
equally. Unfortunately, since the average heavy metal amount could not be found,
cadmium could not be analyzed against the other heavy metals.
Table 9: Average Heavy Metal Percent Subtraction for Toxicity Rating
Lead 2%Mercury 1%Chromium 1%Cadmium 1%
The recyclability index can be lowered by up to 12.5%. This maximum percent
subtraction was the amount needed to lower the automobile rating by one letter grade.
The relative contributions of each of the metals were determined based on their toxicity.
Therefore, depending on the amount of heavy metal present, a corresponding
percent subtraction can be calculated based on the average amount of heavy metal in the
automobile. The percent subtraction (P) for a vehicle being tested can be calculated with
the following equation:
P = (Eq. 7)
P = percent subtraction for each metal,
mtest = selected heavy metal mass in the test vehicle,
mavg = average heavy metal mass in a vehicle (from Table 5),
Pavg = percent subtraction for selected heavy metal for an average vehicle (from Table 9).
The recyclability index to be lowered by up to 12.5%. This maximum percent
subtraction was the amount needed to lower the automobile rating by one letter grade. In
the case where the heavy metal mass may increase the percent subtraction unreasonably
large, the maximum P value is 2.5 times the average percent subtraction (in Table 9).
Therefore, for lead, the maximum percent subtraction is 5% while for mercury,
chromium, and cadmium it is 2.5%. This maximum percent subtraction corresponds to
2.5 times the amount of heavy metal found in an average vehicle.
In order to attach a letter grade to the numerical value determined using the rating
system, the average automobile with average recyclability (75%) and average amounts of
heavy metals (5% percent subtraction) was given a C letter grade. Therefore, the C letter
grade would be set at the rating of 70%. The rating system grading is shown in Table 10
with further breakdowns using plus and minus signs. Having the rating system expressed
on a letter grade system will be easier for the public to understand. Also, the team did not
want to mislead the public in believing that the rating percent reflects the actual percent
recyclability of the automobile (Although the rating is given as a percent, it does not
accurately reflect the recyclability of the automobile because the rating is discounted
based on toxic metal content).
Table 10: Rating System Grading
Grade % rangeA+ 97-100A 93-96A- 89-92B+ 85-88B 81-84B- 77-80C+ 73-76C 69-72C- 65-68D+ 61-64D 57-60D- 53-56F 0-52
Recyclability Index for Test Case
The case study data used for this model is shown in Table 11, based on a generic
1995 US sedan (a synthesis of Dodge Intrepid, Chevrolet Lumina, and Ford Taurus) as
described by Sullivan (1998). Unfortunately, data for a more recent automobile could not
be obtained from any car manufacturer because the manufacturers considered the type-
specific plastic content and toxic metal content of their cars to be proprietary.
Table 11: 1995 Model Year Generic US Family Sedan Material Categories and
Specific Materials (Sullivan 1998)
Material Category/ Material
Material Category/ Material
Plastics Ferrous Metals ABS 9.7 iron (ferrite) 1.5ABS-PC blend 2.8 iron (cast) 132Acetal 4.7 iron (pig) 23Acrylic Resin 2.5 steel (cold rolled) 114ASA 0.18 steel (EAF) 214Epoxy Resin 0.77 steel (galvanized) 357PA 6 1.7 steel (hot rolled) 126PA 66 10 steel (stainless) 19PA 6-PC blend 0.45 Subtotal 985PBT 0.37 FluidsPC 3.8 auto trans.fluid 6.7PE 6.2 engine oil 3.5PET 2.2 ethylene glycol 4.3Phenolic Resin 1.1 gasoline 48Polyester Resin 11 glycol ether 1.1PP 25 refrigerant 0.91PP foam 1.7 water 9PP-EPDM blend 0.1PPO-PC blend 0.025PPO-PS blend 2.2 Subtotal 74PS 0.007 Other MaterialsPUR 35 adhesive 0.17PVC 20 asbestos 0.4Thermoplastic Elastomeric Olefin (TEO)
0.31 bromine 0.23
Subtotal 143 carpeting 11Non-Ferrous Metals ceramic 0.25
aluminum oxide 0.27 charcoal 0.22aluminum (cast) 71 corderite 1.2aluminum (extruded) 22 desiccant 0.023aluminum (rolled) 3.3 fiberglass 3.8brass 8.5 glass 42chromium 0.91 graphite 0.092copper 18 paper 0.2lead 13 rubber (EPDM) 10platinum 0.002 rubber (extruded) 37rhodium 0.0003 rubber (tires) 45silver 0.003 rubber (other) 23
tin 0.067 sulfuric acid - in battery 2.2
tungsten 0.011 textile fibers 12zinc 0.32 wood 2.3Subtotal 138 Subtotal 192
Grand Total 1532
windshield cleaning additives 0.48
The recyclability score for this average 1995 car was determined by the following
The mass of the tires was:
kgmt 45= ,
The mass of the battery could not be directly found from Table 11. The amount of lead in
the battery can be calculated from the total lead mass of 13 kilograms. Since about 95.9%
of this is from the battery (from Figure 2, (Gearhart, 2003)), about 12.5 kilograms of lead
is present in the battery. Also, Table 11 lists 2.2 kilograms of sulfuric acid are from the
battery. Summing these two values, the mass of the battery was found as:
kgmb 7.14= ,
The mass of the fluids was:
kgm fl 74= ,
The mass of ferrous metal was:
kgm f 985= ,
The mass of non-ferrous metal was:
kgm f 138= ,
The mass of PE plastic was:
kgm pe 2.6= ,
The mass of PET plastic was:
kgm pet 2.2= ,
The total mass of the vehicle was:
Thus, the recyclability index for this average car is given by substituting these values into
In order to find the percent subtraction due to the heavy metals, the amounts of
cadmium, chromium, lead and mercury in Table 11 were used. Although the lead amount
in Table 11 is 13 kilograms, as stated before, it was assumed that 95.9% of this weight is
due to the battery (from Figure 2, (Gearhart, 2003)). The remaining 4.1% or 0.533
kilograms was used for the toxicity score rating. Since there was no weight of mercury
listed in the Sullivan (1998) study, the typical value of mercury from Table 5 was used in
this case study. Also, though not all the chromium in Table 11 is hexavalent chromium, a
worst case scenario was analyzed assuming that all the chromium was hexavalent
chromium. This decision was made because there was no further information pertaining
to chromium in the study. Also, there was no data pertaining to cadmium in the study.
Equation 7 above was used to calculate the percent subtraction for lead, mercury
and chromium. The percent subtraction for cadmium was assumed to be 1% (the average
amount of cadmium) since the mass of cadmium in the case study was not available. The
percent subtraction for the case study is shown in Table 12. Then, the final rating was
found for the case study as a C+ (Table 13). This means that the case study vehicle’s
recyclability is similar to an average automobile.
Table 12: Percent Subtraction for the Cas
able 13: Case Study Rating
Subtraction 6.6%Rating Score 76.0%Ratin
Percent SubtractionLead 2.1%Mercury 1%Hexavalent Chromium 2.5%Cadmium 1%Total 6.6%
CHAPTER 4: DISCUSSION
This rating system was an initial attempt to rate the end-of-life impacts of an
automobile. There are many other factors outside the scope of this system that could be
considered to make it more comprehensive and accurate; however, one objective was to
keep the system simple for it to be easily peer reviewed and improved. This project only
considered the automobile’s material as an indicator of an automobile’s end-of-life
impacts. There are many design factors including modular design and minimizing
material diversity that also determine the end-of-life impacts (Graedel, 1998). However,
since it would be difficult to quantify design features, this rating system focused on
objective and readily available material weights. This rating system does not consider the
salvageable parts removed from the ELV since these parts are reused, not recycled. Also,
as discussed later, obtaining manufacturer material data was very difficult. Therefore,
including component parts into the rating system may have been impossible because
component weight lists were probably unattainable.
The removal of high-value parts is not considered in this rating system. The re-use
of high-value reused parts can significantly decrease the environmental impacts of an
ELV, but since these parts are reused, not recycled, they are not considered in the
recyclability calculation of the rating system. Also, to determine if a component is
reusable, or salvageable, the following factors must be considered: condition, model,
year, consumer demand, ease of removal, and ease of repair. Quantifying these factors
would require a significant amount of further research. Also, when these components are
reused, the component’s end-of-life impacts are simply delayed. Once the components
fail, then it will enter the disposal stream, the area where this rating system focuses on.
The fluids and battery will be removed and the automobile will then be taken to the
shredding facility. The battery is considered to be removed since 90% of all lead-acid
batteries are currently recycled (Graedel, 1998). Also, another objective was to keep the
system simple for it to be easily peer reviewed and improved.
An important consideration in the development of this rating system was that it be
simple for the average consumer to understand. The consumer could be expected to
understand the concept of recycling percentage, but not necessarily understand toluene
and benzene masses. Also, showing a “cancer score” based on benzene toxic equivalency
potential could mislead consumers to believe that driving their automobile causes cancer.
This would be a misconception because the cancer score would be based on the car
materials after it is shredded, not while the car is in use. For that reason, the cancer risk
used for calculating a toxicity discount should not be disclosed to the public. Therefore,
in order to simplify the rating and prevent consumer misconception, the recyclability
rating and toxicity ratings were combined. The reasoning behind this is that toxic or
carcinogenic materials in the ELV can be an impediment to recycling and harmful to the
Consumers are becoming more interested in their automobile’s environmental
impacts as indicated by the recent popularity of hybrid automobiles. However, this
impact is focused on only the use phase of the automobile and does not pertain to the
end-of-life impacts. This model can help to give consumers a wider understanding of the
environmental impacts of the automobile they are about to purchase. In the end, future
generations could be educated by seeing a comprehensive life-cycle-rating of an
automobile on the sticker of a new automobile that integrates all the life-cycle phases of
the automobile including fuel efficiency, end-of-life disposal, and manufacturing.
The potential impacts of consumer awareness concerning environmental
conscious purchasing are broadly applicable to various industry sectors. The basic idea of
this rating system - using the recyclability of a product and the toxic ingredients to form a
product rating - could be applied to many industry sectors as well. However, this specific
rating system could not be directly applied to automobiles in all countries. Most
developed countries, such as Japan and those in Europe, have similar recycling processes
and infrastructure as in the United States, therefore this rating system is still relevant.
However, developing countries without proper automobile recycling technology and
infrastructure will have very different ELV processing. Therefore, this rating system
could not be used in such a country.
Another concern is public guidance about prioritizing the fuel efficiency value to
the recyclability index. For a passenger car, the use phase consumes 84% of the total
energy usage over the lifetime of the automobile (Kasai, 1999). This is significantly
larger than the negligible 0.1% of the total energy usage due to the end-of-life phase of
the automobile. Therefore, the public must be informed that the fuel efficiency value is
far more important than the recyclability index rating.
Sensitivity analysis using different automobile makes and models was not
possible since the data was not available. However, various theoretical situations could be
analyzed. The highest possible grade for the case study is a B+ (87.5%). This grade
would be possible if all the plastic in the automobile were recyclable and there were no
toxic metals used (except in the battery). In order for the case study automobile to reach
an A grade, other materials such as glass, fabric, and rubber would need to recycled.
Currently, due to separation technology and market values, these materials are not
In order to improve an automobile’s recyclability index, the manufacturer can
focus on increasing the recyclability score or reducing the toxicity score. When looking at
Table 10, each grade has a 3% range. However, depending on the initial recyclability
index of an automobile will determine the percent amount needed to improve. For
example, if an automobile gets an 84% recyclability index (B), a 1% improvement would
be needed to get a higher index of a B+ (85%). However, if an automobile gets an 81%
recyclability index (B), a 4% improvement would be needed to get the higher index of a
If a manufacturer would like to increase the recyclability score, the recyclable
material (metals, fluids, recyclable plastics) content would need to be increased. The
percent mass of metal was given from DaimlerChrysler, BMW, and Toyota. These data
were graphed in Figure 3 with the case study percent metal mass. Since the percent metal
mass of an automobile can vary from less than 70% to about 80%, the automobile’s metal
amount can change the recyclability index significantly.
A-class C-class E-class S-class 316i Z3 735i 520i Cressida(1996)
Mercedes BMW Toyota n/a
Figure 3: Percent Metal Mass for Various Automobiles
When focusing on the toxicity score, the manufacturer can reduce the amount of
toxic metal used in the automobile. If the manufacturer uses less than half of the heavy
metal amount found in an average automobile over 2.5% will not be deducted from the
final recyclability index.
The recyclability rating described in this thesis should be updated as scrap
markets and recycling technologies change. As more plastics are recycled, the mrp value
in equation 3 will increase, hence increasing the recyclability score. If the mercury,
hexavalent chromium, cadmium and lead are no longer used in automobiles, the rating
system should change to focus on the next most hazardous materials used in the
automobile. The newly selected materials should then be integrated into the toxicity score
to provide incentives for manufacturers to eliminate or reduce the use of such materials.
One of the shortcomings of this model was that it overlooks the separation
technology for recyclable plastics. It was assumed that the PP and PET could be
commercially separated from the ASR to the quality required for the scrap market. The
researchers felt that the most important aspect of any scrap material would be the market
value. Therefore, the scrap market value for plastics was taken as the determining factor
for identifying a plastic as recyclable. The separation technology was not viewed as
important because the researchers felt that if there was a scrap market for a plastic, the
technology would be developed to fulfill this demand. However, if there is no scrap
market for a plastic, technology would not be developed to separate the plastic since there
is no demand.
The plastic separation technology is developing as seen by the industrial scale
recycling of automobile plastics done by MBA Polymers, Inc. in Richmond, California.
This company receives shredded material from North America and has sufficient end
markets for their separated plastics. The company has developed a process to recover
several million pounds of plastics per month from shredded material streams from
automobiles, appliances and computers (MBA, 2000). They separate out the plastic to PP,
HIPS (high-impact polypropylene), ABS (acrylonitrile butadiene styrene), PC
(polycarbonate), and PC/ABS blends (Taylor, 2002). Our mrp value did not include all the
plastics separated by MBA Polymer technology because we could not verify a scrap
market value for the other plastics. However, the mrp value will change as plastic
recycling expands – signified by opened MBA Polymer plants in Guangzhou, China
(November 2005), and Kematen, Austria (March 2006) (Arola, 2006).
Design for the Environment/Disassembly
One of the methods of recovering recyclable plastics or any other material would be
to design the automobile for easily disassembly. Coupled with using fewer material types
and material labeling, components could be sorted according to material, and recycled.
This approach of having the manufacturer design the automobile for easier recycling is
called Design for the Environment (DfE), Design for Disassembly (DfD) or Design for
Recycling (DfR). Within the current recycling process, components (bumpers,
windshields) would be removed for recycling when having fluids drained and reusable
parts removed. Therefore, the recycling yards would in the best situation to remove
components for recycling.
One of the shortcomings of this model is that it does not include a factor for DfE.
reward manufacturers that make efforts in reducing the environmental impacts by
implementing DfE techniques. The main reason why a factor for DfE could not be
included was because the input of this system was a material listing of an automobile, not
a design schematic. Another model would be needed to objectify the effectiveness of DfE
techniques compared to one another. Also, such DfE techniques were not seen as to
change the overall recyclability of an automobile given the current recycling process. As
stated previously, the recycling yard will only dismantle an automobile for a profit.
Therefore, components are removed from an automobile because these can be sold at a
profit, since they will be reused. However, components, which can be removed for
recycling (e.g. bumpers), are not because these cannot be sold for a profit. The cost of
paying an American technician for removing a bumper is far more than the salvage value,
if any, for the plastic. However, in Holland, a successful automobile recycling yard
removes seat foam, windshields, and rubber stripping for a profit. This is done by
government subsidies which support the recycling of these materials. A few American
automobile recycling yard owners commented on this by saying that such subsidies
would not be preferred in the US because along with subsidies would come a lot of other
government demands. Such recyclers would not want government involvement in their
entrepreneurial industry (IARC, 2006). Therefore, having manufacturers design
automobiles to be dismantlable/recyclable addresses only half of the problem. Without a
high market price for the material, the recycling yards will not dismantle the automobile
for recycling. This concept was the center of research done by (Great Lakes, 1998).
Another factor is if the auto recycling yard will change the recycling process to adjust
for DfE implementation. To clarify, most recycling yards drill a hole in the oil tank to
remove the oil. If Ford designed the oil tank to drain more effectively with a particular
process or tool, the yard may not change and still drill a hole to drain the oil. So, if one
manufacturer designs an automobile to disassemble faster by following a certain process,
the recycling yard may not care and continue to dismantling the car the way it always
does. This can be overcome by either dispersing dismantling information to recycling
yards, or having manufacturers work with specific recycling yards, as in Europe.
Providing dismantling information is very difficult because there are many unlicensed or
illegal recycling yards that may not be interested or difficult reach. If manufacturers work
with specific recycling yards, then those yards will understand how to adjust the
recycling process according to new advancements in DfE approaches. However, the only
time an automobile manufacturer became involved with recycling yards was when Ford
purchased recycling yards to get into the industry. However, this became a failed venture
and Ford ended up selling the 22-yard network, known as Greenleaf Auto Recyclers, to
Schnitzer Steel Industries (Metal Bulletin, 2006).
Another way for manufacturers to get involved with the recycling industry would
be to actively communicate with automobile recycling trade associations. Europe and
Japan have passed legislation increasing automobile the recyclability, but US auto
recyclers and manufacturers do not want such legislation. However, both parties,
especially recyclers, would like to increase the recyclability percent of automobiles at the
same rate as Europe and Japan. Recyclers would hope that this be done by working with
manufacturers to close the loop between design and disposal. If manufactures actively
communicate with automobile recycling trade associations, they will be able to
understand the current obstacles of automobile recycling. At the trade association
conferences, many recyclers are open to give suggestions on how automobile design can
be altered for recycling. This communication would increase the recyclability of
automobiles without legislation.
Automobile Recycling Yard Practice
One of the main shortcomings of this project is in not addressing
unregulated/illegal automobile recycling yards. Actually, the most effective way to
reduce the environmental impacts of automobile recycling would be to get more
recycling yards into environmental compliance. The yards which are part of professional
organizations (e.g. Automotive Recyclers Associating) are very conscious of their
environmental impacts and work within environmental regulations. However,
unregulated yards are able to provide services at a lower price, undercutting these
environmentally responsible yards. The way unregulated yards do this is by working
without regard to environmental compliance. Due to higher demands on certified
recyclers, there are a growing number of unlicensed dismantlers not adhering to
environmental regulations (Arbitman, 2003). In California, the majority of ELVs are
disposed by unlicensed or illegal operators that do not follow the established industry
standards for recycling vehicles. Only about 40% or less of the ELVs are recycled by
licensed professional recyclers (Cowell, 2006a). Unregulated yards are also a significant
problem for automobile recycling industries in other countries, such as Japan and Europe.
The rating system described in this paper assumes that the ELV would go to a licensed
recycling yard that removes tires, batteries and fluids. However, if an ELV is taken to a
unregulated/illegal yard, this rating system becomes obsolete. Having more yards
licensed will also support automotive recycling legislation (e.g. mercury switch removal).
Having such legislation is not useful when there are so many unregulated/illegal yards
that stay in business without complying.
The critical barrier to testing this rating system was the difficulty obtaining
manufacturer data on automobiles. In order to implement this rating system,
comprehensive material listings are needed from manufacturers. Unfortunately, such
information is often proprietary and not in the public domain. In order to obtain such
information for running examples for this study, various industry professionals were
contacted at automobile manufacturers such as GM, Ford, Daimler Chrysler, Toyota,
Honda, Nissan, BMW, Hyundai, Fiat, Isuzu, Mazda, Mitsubishi, Porsche, Suzuki,
Volkswagen, and Volvo. Also, to locate references and obtain more industry information,
trade associations dealing with ELVs were contacted. These trade associations include
Automotive Recyclers Association, State of California Auto Dismantler’s Association,
Japan Automotive Recyclers Association, Automotive Recyclers of Canada, European
Group of Automotive Recycling Association, Institute of Scrap Recyclers Industries, and
the Steel Recycling Institute. Although contact was made, the authors were unable to
obtain comprehensive material listings through any of these channels.
Comparison to Other Rating Systems
In Europe, the ISO 22628 standard is used to measure automobile recyclability
(The International Organization for Standardization, 2002). The rating system described
in this thesis uses this standard as a basis. The main difference between the ISO standard
and the model discussed in this paper is that the ISO standard does not combine the
recyclability and impacts of toxic automobile contents. There are two measurements
calculated in the ISO method: recyclability and recoverability (The International
Organization for Standardization, 2002). The difference between these two measurements
is that the recyclability includes the mass of the automobile that can be incinerated for
energy recovery, where recoverability does not (The International Organization for
Standardization, 2002). Since ASR is not incinerated in the US (Keoleian, 2001), the
recyclability score described in this paper is more closely related to the ISO 22628
recoverability measurement. There are also a few other differences between the ISO
22628 standard and the recyclability score described in this paper. The ISO standard
includes other masses such as the mass of components or materials removed during the
pre-treatment step. These items include fluids, oil filters, gas tanks and tires. The ISO
standard also includes the mass of salvageable (reusable) and recyclable components.
Salvageable components are determined by their accessibility, fastener technologies,
material composition and proven recycling technology (The International Organization
for Standardization, 2002). The ISO standard includes salvageable parts because it
measures recyclability at the time the ELV is being recycled. The rating system described
in this paper does not include salvageable parts because it is designed to indicate the
automobile’s recyclability when the automobile is retired 10 years in the future. In order
to include salvageable parts, the model would have to include future projections for
automobile component market value and automobile dismantling and recycling
technology. Projecting these concepts was beyond the scope of this project but could be
done in future research. The rating system described in this paper includes the mass of
fluids; however, it does not include the mass of removed components (gas tanks, oil
filters, salvageable parts). These mass terms are not included because of reasons
discussed earlier. The ISO standard also includes the mass of non-metallic residue. This
is similar to the weight of recyclable plastics (mrp) described in this paper. The ISO non-
metallic residue mass is based on proven recycling technologies and can include the mass
of many materials such as glass and rubber (The International Organization for
Standardization, 2002). The mrp, described in this paper, only includes the mass of
selected plastic, and is based on the recycling market for these plastics.
For hazardous materials, Europe has banned the use of mercury, hexavalent chromium,
cadmium, and lead. There are exemptions to these restrictions as shown in Table 14.
Table 14: Hazardous Material Use Exemptions in Europe (Beckett, 2005)
Hazardous Material Application ExemptionLead alloys
batteriesvibration dampenersstabilizers in elastomerssolder in electric applications
Hexavalent Chromium corrosion preventive coatingsMercury discharge lamps
instrument panel displaysCadmium thick film pastes
batteries for electric vehicles
The rating system described in this paper only exempts the lead used in the
battery because lead batteries are removed before shredding and they are highly recycled
(EPA 2006). The other European exemptions are not included in this rating system
because an automobile’s component list was unattainable. The purpose of this thesis was
to create a recyclability index based on an automobile’s material list. This would include
the types and amounts of the toxic metals used in the automobile. However, this material
list would not state if the toxic metal was used in an alloy or a switch. Therefore, the
European exemptions could not be applied to this rating system since toxic metal use
could not be determined based on the rating system’s input: the material list. If the
application of the toxic metal was attainable, it would have been possible to see the
effects of using the EU exemptions in the rating system. This system will equally
penalize all manufacturers for the use of the hazardous materials and will encourage
manufacturers to find material substitutions. As the four substances of concern are phased
out from auto manufacturing the rating system could be adjusted to include other
hazardous materials such as sodium azide used in air bags. Most vehicles sold in the
United States contain about 0.7 pounds of azide. This material is a highly toxic, broad-
spectrum biocide and, when in the aqueous phase, hydrolyzes to volatile hydrazoic acid
The Development Process
The dynamic process of developing this model consisted of data gathering by the
graduate student, and discussions with a multidisciplinary team of advisors. The advisory
board consisted of Dr. Yarrow Nelson (Environmental Engineering), who served as the
major advisor, Dr. Andrew Kean (Mechanical Engineering), Dr. Sam Vigil
(Environmental Engineering), Dr. Hal Cota (Environmental Engineering), and Dr. Linda
Vanasupa (Materials Engineering). Professor Margot MacDonald was also consulted on
an individual basis. These advisors provided more ideas, and made sure the rating system
was based on realistic and quantifiable factors. The main contribution from the advisory
board was identifying the relevant information about the automotive recycling industry
pertaining to the project’s objective. Weekly meetings were held with the graduate
student and major advisor where various models were developed measuring the impacts
of ELVs. Monthly meetings were held with numerous professors in order to obtain
outside input while developing the model. On May 9th and 10th, the EPA National
Sustainability Design Expo was attended where the project was presented to the public
and industry judges (see Appendix A).
On May 25th, an ENVE 450: Industrial Pollution Prevention class was taught
focusing on Design for the Environment in the automobile industry. This model was
taught to the class with corresponding homework assignment and test questions (See
Appendix B). The final presentation of this project will be at the 2006 Annual Air and
Waste Management Association Conference and Exhibition.
Through attendance at national and international conferences much was learned
about the complexities and dynamics of the current automobile recycling industry. It was
critical to attend these conferences in order to understand the impacts of recent Japanese
and European automobile recycling legislation on the world market. The conferences
• Automotive Recyclers Association 62nd Annual Convention and Exposition o September 21-24, 2005 o Tucson, Arizona
• EcoDesign2005: 4th International Symposium on Environmentally Conscious Design and Inverse Manufacturing
o December 12-14, 2005 o Tokyo, Japan
• 6th International Automobile Recycling Congress o March 15-17, 2006 o Amsterdam, Netherlands
The other factor in helping reach success was the support from the automobile
recycling industry professionals including, but not limited to, the Automobile Recyclers
Association, the State of California Auto Dismantler’s Association, the Automotive
Recyclers of Canada, the European Group of Automotive Recycling Association, the
Japanese Automobile Recyclers Association, the Institute of Scrap Recyclers’ Industry,
the Steel Recyclers’ Association, previous automobile recycling researchers, and
attendees of the International Automobile Recyclers Congress.
CHAPTER 5: FUTURE RESEARCH
The scope of this thesis included just the development of the ELV rating system.
Proposed steps to implement this rating system would constitute a second phase of
research and this second phase is described in this section. Phase 2 would further develop
the recyclability index through work consisting of 3 parts:
1. Peer review of the existing model
2. Model refinements
3. Development of an implementation strategy
Peer Review of the Existing Model
The peer review of the recyclability index developed in Phase 1 research would
use feedback from industry professionals to determine the feasibility and technical
soundness of the work up to now. This peer review would be accomplished using a
number of different sources to provide multiple perspectives. Each of these sources is
Air and Waste Management Association
The Phase 1 work will be presented at a technical session of the 99th Annual Air
and Waste Management Association Annual conference being held June 20-23, 2006.
Presenting the Phase 1 model at this conference will allow the model to be scrutinized by
many of the organization members consisting of environmental professionals from
around the world.
Professional trade associations
During the Phase 1 research, many contacts were made in various trade associations
relating to automotive recycling. Allowing these industry professionals to review the
model is expected to generate many important suggestions. Such contacts include officers
and executive committee members of the following organizations:
• Automotive Recyclers Association (United States Branch)
• Automotive Recyclers of Canada
• Bureau of International Recycling
• European Group of Automotive Recycling Associations
• Institute of Scrap Recyclers Industries
• Japan Automotive Recyclers Association
Also, during the Phase 1 research, contact was made with the environmental
researchers at automotive manufacturers. Such resources who can be contacted include
David Raney at Honda, Claudia Duranceau at Ford, and Candace Wheeler at General
Other Industry Professionals
Other professionals who have been contacted through the Phase 1 research who
could be contacted again for advice include Kent Kiser (Publisher and Editor-in-Chief for
Scrap Magazine), Richard Paul (automobile recycling consultant), Manfred Beck
(Publisher and Editor for Recycling International magazine), and Charles Griffith (Auto
Project Director at the Ecology Center, a Michigan-based environmental organization).
Additionally, new contacts could include other automobile recycling researchers such as
Nakia Simon at Daimler Chrysler, Ed Daniels at Argonne National Laboratory, Prof.
Edwin Tam at the University of Windsor in Ontario Canada and Dr. Greg Keoleian at the
Center for Sustainable Systems at the University of Michigan.
When peer review has been completed, the model could be refined in response to
the concerns that were addressed. Possible refinements could include adding more toxic
materials to the toxicity score, and changing the types of recyclable plastics.
The feasibility of implementation could also be evaluated using the Gabi DfX
program. Designers use this software to help design automobiles because it integrates the
European ELV directive into the product design (GaBi 2006). This software aids in
designing automobiles to meet 85-95% recyclability rates and the minimal use of heavy
metals. Similar to this project’s rating system, the Gabi software is able to calculate the
recyclability of the automobile by using the material composition and structure – how the
material is integrated into components. If the materials are easily separated, then they will
be easily recycled. If two materials are integrated such that they are easily separated,
there will be a higher recyclability rate. By using this program, the researcher will see
how this software measures an automobile’s recyclability due to the material composition
as well as material integration into a part.
More case studies could be examined using the automobile recycling information
from the International Dismantling Information System (IDIS) and International Material
Data System (IMDS) databases. Twenty-five vehicle manufacturers make up a
consortium that created the IDIS database. This software helps to optimize ELV
recycling by providing information on potentially recyclable vehicle parts, filter data
based on parts or materials of a car, and provide dismantling manuals. The database lists
around 59,000 car components for 1,069 vehicle models from 25 car manufacturers. The
51 brands referenced in IDIS represent more than 95% of the current automotive
European market, as well as all the major manufacturers from Japan, Korea and the
United States (IDIS, 2004). Audi, BMW, Ford, Opel, Porsche, VW, and Volvo joined to
create the International Material Data System (IMDS), an archive of all materials used in
manufacturing an automobile. Currently there are 18 companies involved in providing
this information. Although IMDS was developed by a number of European carmakers,
North American and Asian manufacturers have since embraced the system (International,
2006). The IDIS and IMDS automobile material database information could both be used
to run more case studies.
Finally, the Automotive Recyclers Association should be contacted to see how
salvageable parts could be implemented into the rating system. The reusability of an
automobile component could then be determined and the weight of these components
could be added to the recyclable content.
The last step of Phase II would be to determine the strategy for implementing the
model and disseminating the rating information to the public. For example, methods for
including the rating information on newly manufactured automobile stickers as well as
the EPA website should be explored. Some of the key topics to be discussed are EPA
agency approval, vehicle recycling program development, data acquisition, and a quality
control procedure. To develop methods of incorporating the recyclability index on new
car stickers, key staff at the U.S. EPA should be contacted in order to understand the
steps and issues concerning implementing the model to these stickers.
The EPA has a Green Vehicle Guide website that rates the environmental
performance of vehicles during the use phase. It clearly states on the website that “other
environmental factors, such as recyclability of the vehicle” are not accounted for (EPA ,
2006). The EPA’s Green Vehicle Guide project members should be contacted to see what
steps need to be taken and which people need to be contacted to expand the guide to
include end-of-life impacts of the automobile into the website.
After refining the model, a minimum of 4 additional vehicles should be rated in
order to test and strengthen the model. Sensitivity analysis could be used to show how
specific components affect the final rating. For example, the rating deviation could be
examined when a mercury switch is replaced with a non-hazardous substitute.
An example project schedule is shown in Table 15.
Table 15: Proposed Phase II Project Schedule
Sept. Oct. Nov. Dec. Jan. Feb. March April May June July Aug.ARA ConferenceContact peer reviewers
Receive and clarify peer reviewer's feedback
Identify implementation strategy
Refine modelISRI ConferenceWrite report
Project Schedule (2006-2007)
CHAPTER 6: CONCLUSIONS
This project was successful in creating an ELV rating system that included
recyclability and toxic metal content. Similar to the fuel efficiency value, this rating
system’s score could be posted on new vehicle stickers, the EPA website or any other
educational media. This rating system has two parts: one based on recyclability and one
based on toxicity. The recyclability portion is based on the content of ferrous and non-
ferrous metal content (which is 100% recyclable) and plastic for which there is a market
for recycling. The toxicity index is based on the content of lead (excluding batteries,
which are recycled), mercury, cadmium and hexavalent chromium. The toxicity index
subtracts from the recyclability portion in order to give the final rating for an automobile.
When tested on a generic 1995 automobile, the rating system outputted a C+ grade
(76.0%). Though the system rated the automobile at a B rating (82.6%), the toxicity
rating lowered the final index by 6.6%, giving a final index of 76.0%. The recyclability
part of the index was adapted from the ISO 22628 standard (The International
Organization for Standardization, 2002), while the percent subtraction of heavy metals
was an original idea. Only one case study could be done due to the limitation of obtaining
manufacturer data. If a similar project is to be done again, it would be crucial to establish
partnerships with automobile manufacturers to be able to obtain manufacturer data. In
order to implement this rating system, comprehensive material listings are needed from
manufacturers, possibly mandated by the EPA.
Few consumers understand what happens to automobiles when they reach the
end-of-life, but this index could help them rate potential environmental impacts. It is
hoped that public disclosure of this rating system would prompt automobile
manufacturers to design cars with better recyclability. In this way, this project could
improve quality of life by conserving landfill space and preventing the use of hazardous
materials that could potentially be released into the environment. This project could
ultimately lead to a complete sustainability rating or life-cycle rating. After this research
is completed, it could be integrated with a use-phase rating (possibly determined by the
fuel efficiency) and a manufacturing phase rating (possibly determined by the ISO 14001
certification) to ultimately generate a complete life cycle rating.
The main shortcomings of this system are the exclusion of unregulated
automobile recycling yards and manufacturers attempt to implement Design for the
Environment (DfE) techniques. The most effective way to reduce the environmental
impacts of automobile recycling would be to get more recycling yards into environmental
compliance. The rating system described in this paper assumes that the ELV would go to
a licensed recycling yard that removes tires, batteries and fluids. However, if an ELV is
taken to an unregulated/illegal yard, this rating system becomes obsolete. The main
reason why a factor for DfE could not be included was because the input of this system
was a material listing of an automobile, not a design schematic. However, if
manufacturers actively communicate with automobile recycling trade associations,
environmental impacts of automobiles would be reduced.
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I. Class Lecture Notes 1. Automobile Recycling
a. Process Flow Diagram of Automobile Recycling
Mandatory Removed Materials
Reusable Parts (body
Automotive Shredder Residue
Hulk (steel frame, foam seats)
b. Deriving the equation for the Recyclability Index (Ri) – Initial Ri = (mrecycled)/(mtotal) Though not seen on the process flow diagram, a mrecyclable plastics term will be
included in to the mrecycled because research is being conducted in recycling plastic from automotive shredder residue and a few companies are already recycling this plastic on an industrial scale. Recyclable plastic is defined as plastics with a scrap market value. At the time of this research only PE and PET plastics had a scrap market value, therefore, these plastics will be listed as recyclable.
= (mmandatory removed mat. + mresellable parts + mmetal + mrecyclable plastics) / (mvehicle) * 100 Determining the term mresellable parts is extremely difficult because it would
involve modeling the reusability of a used car component. Since this could not be done during this project, the mass of the resellable parts would be distributed among other variables (mmetal, mrecyclable plastics), defined by materials. For example, even though the transmission may be reused, it would be seen in this model as a mass of ferrous and/or nonferrous metal.
= (mfluids + mtires + mbattery + 0 + mferrous + mnonferrous + mpet + mpe)/mvehicle *100 Equation 1: Ri = (mfluids + mtires + mbattery + mferrous + mnonferrous + mpet + mpe)/mvehicle *100
c. Example Problem 1: Given: Automobile Material List Tires = 45kg Battery = 14.7kg Plastics = 43kg (PE=6.2 kg; PET=2.2 kg) Nonferrous metals = 138 kg Ferrous metals = 985 kg Fluids = 74 kg Other materials = 132.3 kg Find: Ri (Recyclability Index – initial) Solution: Ri = (mfluids + mtires + mbattery + mferrous + mnonferrous + mpet + mpe)/mvehicle *100 = (74+45+14.7+985+138+2.2+6.2) kg / (45+14.7+43+138+985+74+132.3) kg *100 Ri = 88.3%
2. Automobile Toxicity a. Toxicity Score for Automobiles
i. Based on 4 heavy metals 1. lead – in wheel weights – brain and kidney damage 2. hexavalent chromium (chromium6+) – in surface coatings
(bolts) – lung cancer 3. mercury – in light sources – brain and nervous system
damage 4. cadmium – in brake pads – kidney damage
b. Environmental release
The metal recovered from the shredding facility can be contaminated with mercury and lead. This has caused lead to contaminate the metal from
shredding facilities. Also, furnaces which use metal from shredding facilities have become one of the highest mercury air emitters.
The automotive shredder reside sent to the landfill can be contaminated with
any of the four toxic metals. In California, automotive shredder residue is hazardous material if it exceeds certain concentrations of these 4 toxins.
c. Toxic Equivalency Potential (TEP)
A measuring system, but instead of liters, inches, seconds, it uses pounds of benzene/toluene to compare toxic materials (e.g. heavy metals).
i. 2 parts 1. cancerous risk measured in pounds of benzene 2. noncancerous risk measured in pounds of toluene
ii. - 1 pound of lead = 28 pounds of benzene = 580,000 pounds of toluene
- 1 pound of mercury = 0 pounds of benzene = 14,000,000 pounds of toluene - 1 pound of cadmium = 26,000 pounds of benzene = 1,900,000 pounds of toluene - 1 pound of hexavalent chromium = 130 pounds of benzene = 2,400 pounds of toluene
iii. However, there is not one pound of mercury in a car. Far less is used; 0.002 pounds to be exact. The following table shows the average amount of toxic metal in an automobile and the corresponding benzene and toluene weights
Toxic Metal mcar (pound) mbenzene (pound) mtoluene (pound)
Lead 1.1 31 2,090,000Hexavalent Chromium 0.034 5 87
Mercury 0.002 0 28,000Cadmium n/a n/a n/a
1. Lead is the most toxic 2. Hexavalent chromium and mercury has the same toxicity
a. Chromium has 5 more pounds of benzene risk b. Mercury has 28,000 more pounds of toluene risk c. Designer decision that 5 pounds of benzene and
28,000 toluene are equivalent
v. Relate the amount of heavy metal to the initial recyclability index. 1. The following table shows the percent subtraction for an
automobile having the average amount of toxic metal
Lead 1.1 2%*Mercury 0.034 1%
Hexavalent chromium 0.002 1%Cadmium n/a 1%
* Designer decision: percent subtraction for average amount of heavy metal is 1%; however, due to toxicity of lead, it is raised to 2%
vi. Derive equation for percent subtraction due to toxicity: - first, set up ratio: (maverage)/(Paverage) = mtest (mass of heavy metal in car you are testing)/(Ptest (percent subtraction for car you are testing) - solve it in terms of Ptest Equation 2: Ptest = (mtest)/(maverage) * Paverage
vii. Example Problem 2 Given: Automobile material list
Toxic metal mass (pounds)Lead 1.18
Hexavalent Chromium 0.085Mercury 0.002
Cadmium n/a Find: Total percent subtraction due to heavy metal content Solution: Ptotal,test (total percent subtraction) = Plead + Pmercury + Phexavalent
chromium + Pcadmium Plead, test = (mlead, test)/(mlead, average) * Plead, average =1.18 pounds/(1.1 pounds) *2% = 2.15% Pmercury, test = (mmercury, test)/(m mercury, average) * P mercury, average =0.002 pounds/(0.002 pounds) *1% = 1%
P hexavalent chromium, test = (m hexavalent chromium, test)/(m hexavalent chromium, average) * P hexavalent
chromium, average =0.085 pounds/(0.034 pounds) *2% = 2.5% Pcadmium, test = (m cadmium, test)/(m cadmium, average) * P cadmium, average =(assume the test car has the average mass of cadmium) =(m cadmium, average)/(m cadmium, average) * P cadmium, average = P cadmium, average =1% Ptotal,test = (2.15+1+2.5+1)% = 6.65% Ptotal,test = 6.65%
3. Final Recyclability Index (Rf) a. Rf = Ri (initial recyclability index) – Ptotal (total percent subtraction due to
heavy metals) Equation 3: Rf = Ri - Ptotal b. Example Problem 3 Given: Previous 2 example problems Find: Rf Solution: Rf = Ri - Ptotal = (78.7-6.65)% = 72.05% Rf = 72.05%
4. Important Obstacle/Opportunity : Economics a. Is the market value for the recyclable material more than the cost for
recovering the material?
b. Example 4 (Same as handout): Given:
Table 1: Disassembly procedure and times for one air conditioning unit time (seconds)
Remove screws of the top panel 31Disassemble the control box 28Disassemble the lower cover of the control box 28Remove snap fits and remove the control box 7Disassemble inner portion of the control box 52Remove the lower panel of the control box 28Disassemble the fan grill 28Disassemble the fan and fan motor from the grill 30Disassemble the motor fan and fan blade 7Disassemble the two valves 37Disassemble the valves from heat exchange and tubes 1273Remove the compressor from bottom panel 32Total 1582
Table 2: Scrap Market Prices (as of May 2006)
material unit valueFerrous $150/tonNon-ferrous $0.95/poundHDPE $0.31/poundPET $0.21/poundmixed PET and HDPE $0/pound
Table 3: Material listing for one air conditioning unit
material mass (kg)Copper 3.85HDPE 2.50Steel 9.75Aluminum 2.50Rubber 0.11Total 18.71
Disassembly plant information Labor is $15 per hour. For 100,000 appliances, the factory has calculated that the energy cost to run the operation is $516 and tools will cost $40,000.
Find: Is recycling an air conditioning unit profitable? If so, by how much?
Solution: Cost for dismantling Labor cost = 26.4min*hour/60min*$15/hour=$6.6/appliance Total energy and tools cost for 100,000appliances=$516+$40,000=$40,516
Total energy and tools cost for 1 appliance = $40,516/100,000 appliances= $0.41/appliance Total cost for dismantling 1 appliance = labor cost+energy and tool cost= =$6.6+$0.41= $7.01
Scrap value for material Copper = amount * scrap value = 3.85 kg (from Table 3: Material listing) * 2.2 pounds/ kg (conversion factor) * $0.95/pound (from Table 2: Scrap Prices) = $8.06
Table 4: Value for scrap material
material mass (kg) mass (pounds) unit value ($/pound) $Copper 3.85 8.49 0.95 8.06HDPE 2.50 5.51 0.31 1.71Steel 9.75 21.50 0.08 1.61Aluminum 2.50 5.51 0.95 5.24Rubber 0.11 0.25 0.00 0.00Total 18.71 41.26 16.62
Profit = Value - cost=$16.62-$7.01=$9.61 Yes, recycling the air conditioning units is profitable by $9.61 per unit.
Example Problem 4: Recycling air conditioning units for a profit
GIVEN: Table 1: Disassembly procedure and times for one air conditioning unit
time (seconds)Remove screws of the top panel 31Disassemble the control box 28Disassemble the lower cover of the control box 28Remove snap fits and remove the control box 7Disassemble inner portion of the control box 52Remove the lower panel of the control box 28Disassemble the fan grill 28Disassemble the fan and fan motor from the grill 30Disassemble the motor fan and fan blade 7Disassemble the two valves 37Disassemble the valves from heat exchange and tubes 1273Remove the compressor from bottom panel 32Total 1582 Table 2: Scrap Market Prices (as of May 2006) material unit valueFerrous $150/tonNon-ferrous $0.95/poundHDPE $0.31/poundPET $0.21/poundmixed PET and HDPE $0/pound Table 3: Material listing for one air conditioning unit material mass (kg)Copper 3.85HDPE 2.50Steel 9.75Aluminum 2.50Rubber 0.11Total 18.71 Disassembly plant information Labor is $15 per hour. For 100,000 appliances, the factory has calculated that the energy cost to run the operation is $516 and tools will cost $40,000.
FIND: Is recycling an air conditioning unit profitable? If so, by how much? Solution Value for scrap material material mass (kg) mass (pounds) unit value ($/pound) $Copper 3.85 8.49 0.95 8.06HDPE 2.50 5.51 0.31 1.71Steel 9.75 21.50 0.08 1.61Aluminum 2.50 5.51 0.95 5.24Rubber 0.11 0.25 0.00 0.00Total 18.71 41.26 16.62 Cost for dismantling Labor cost = 26.4min*hour/60min*$15/hour=$6.6/appliance Total energy and tools cost for 100,000appliances=$516+$40,000=$40,516 Total energy and tools cost for 1 appliance = $40,516/100,000 appliances=
$0.41/appliance Total cost for dismantling 1 appliance = labor cost+energy and tool cost=
=$6.6+$0.41= $7.01 Profit = Value - cost=$16.62-$7.01=$9.61 Yes, recycling the air conditioning units is profitable by $9.61 per unit.
III. Homework Problem 1. Automobile Recyclability Rating Given the material listing below, what is the final recyclability rating for the automobile? Table 1: Automobile material listing Material Category/ Material
Plastics 151PE 10.2
PET 6.2Tires 45Battery 14.7Non-Ferrous Metals 168Ferrous Metals 885Fluids 66Other Materials 132.3Grand Total 1462 Table 2: Automobile heavy metal content
mass (pounds)Lead 0.5Hexavalent chromium 0Mercury 0.004Cadmium n/a* *Assume cadmium content is the average amount found in an automobile
Problem 2. Economics of Recycling Determine if recycling an air conditioning unit is profitable for scenario A and B? If so, by how much? In scenario B, what will happen to the costs if the 2 plastic types were replaced with #3 PVC plastic and #5 PP plastic? Table 1: Scenario A - Material listing for one air conditioning unit material mass (kg)Copper 7.73Steel 19.50Aluminum 5.00Rubber 0.11Total 32.34 Table 2: Scenario B - Material listing for one air conditioning unit material mass (kg)Copper 0.77Steel 1.95Aluminum 0.50Rubber 0.11HDPE 2.34PET 0.31Total 5.98 Use the disassembly plant information, and Table 1 and 2 from the example problem handout. Remember that steel is a ferrous metal while copper and aluminum are non-ferrous metals.
IV. Homework Solutions
Problem 1: Equation 3: Rf = Ri - Ptotal Equation 1: Ri = (mfluids + mtires + mbattery + mferrous + mnonferrous + mpet + mpe)/mvehicle *100 Ri = (66+45+14.7+885+168+10.2+6.2) kg / (151+45+14.7+168+885+66+132.3) kg *100 Ri = 1195.1/1462*100 Ri = 81.7% Ptotal,test (total percent subtraction) = Plead + Pmercury + Phexavalent chromium + Pcadmium Equation 2: Plead, test = (mlead, test)/(mlead, average) * Plead, average Plead, test =0.5 pounds/(1.1 pounds) *2% = 0.9% Pmercury, test = (mmercury, test)/(m mercury, average) * P mercury, average =0.004 pounds/(0.002 pounds) *1% = 2% P hexavalent chromium, test = (m hexavalent chromium, test)/(m hexavalent chromium, average) * P hexavalent chromium, average =0 pounds/(0.034 pounds) *1% = 0% Pcadmium, test = (m cadmium, test)/(m cadmium, average) * P cadmium, average =(assume the test car has the average mass of cadmium) =(m cadmium, average)/(m cadmium, average) * P cadmium, average = P cadmium, average =1% Ptotal,test = (0.9+2+0+1)% Ptotal,test = 3.9%
Rf = Ri - Ptotal = (81.7-3.9)% = 72.05%
Solution: Rf = 77.8%
Problem 2: Cost for dismantling (same as in handout) Labor cost = 26.4min*hour/60min*$15/hour=$6.6/appliance Total energy and tools cost for 100,000appliances=$516+$40,000=$40,516 Total energy and tools cost for 1 appliance = $40,516/100,000 appliances=
$0.41/appliance Total cost for dismantling 1 appliance = labor cost+energy and tool cost=
=$6.6+$0.41= $7.01 Scenario A: Scrap material value material mass (kg) mass (pounds) unit value ($/pound) $Copper 7.73 17.04 0.95 16.19HDPE 0.00 0.00 0.31 0.00Steel 19.50 43.00 0.08 3.22Aluminum 5.00 11.03 0.95 10.47Rubber 0.11 0.25 0.00 0.00Total 32.34 71.32 29.89 Profit = Value - cost=$29.89-$7.01=$22.88
Yes, for scenario A, recycling the air conditioning units is profitable by $22.88 per unit. However, notice the reason for this is due to all the metal in the AC unit. This may impact other features such as weight and capital cost (if metal is more expensive than plastic). Scenario B: Scrap material value material mass (kg) mass (pounds) unit value ($/pound) $Copper 0.77 1.70 0.95 1.61PET 0.31 0.68 0.21 0.14HDPE 2.34 5.16 0.31 1.60Steel 1.95 4.30 0.08 0.32Aluminum 0.50 1.10 0.95 1.05Rubber 0.11 0.25 0.00 0.00Total 5.98 13.19 4.73 Profit = Value - cost=$4.73-$7.01= - $2.28
No, for scenario B, recycling the air conditioning units is not profitable because you will lose $2.28 per unit processed.
If plastics in Scenario B were replaced by #3 and #5 plastics The scrap value from HDPE ($1.60) and PET ($0.14) will be eliminated because #3
and #5 plastics do not have a scrap value. Therefore, the total scrap value for one AC unit will become: $4.73 - ($1.60HDPE scrap value+ $0.14PET scrap value) = $2.99 Then the total profit is: ($2.99-7.01) = -$4.02
If the plastics of scenario B were replaced by #3 and #5 plastics, recycling will become more uneconomical since $4.03 will be lost per AC unit processed.
V. Test Questions Problem 1. Automobile Recyclability You are working for an automobile manufacturer designing new cars. With the rising prices of gasoline, your boss tells you that they intend to make the car lighter for higher fuel efficiency. In order to do this, many of the metal parts will be replaced with plastic ones. Your boss asks what effect this will have on the recyclability of the automobile. What will your response be? Problem 2. Automobile Recyclability Rating You work for an automobile manufacturing company who has recently become very environmentally conscious. They have been analyzing the materials used in one of their automobiles to reduce the negative impacts on the environment. The head engineer of a design team has proposed a new design (Scenario B) that would reduce the amount of lead in an automobile in half; however, the amount of hexavalent chromium will double. The engineer asks if this new design is better for the environment when compared to the original design (Scenario A). How would you respond? In your response, please give the difference between the final recyclability indices (Rf) of the two designs. The material information is given below. Table 1: Automobile material listing for Scenario A and Scenario B Material Category/ Material
Plastics 151PE 12
PET 4Tires 45Battery 14.7Non-Ferrous Metals 180Ferrous Metals 870Fluids 70Other Materials 169.3Grand Total 1500 Table 2: Automobile heavy metal content for Scenario A
mass (pounds)Lead 2Hexavalent chromium 0.015Mercury 0.002Cadmium n/a* *Assume cadmium content is the average amount found in an automobile
Table 3: Automobile heavy metal content for Scenario B mass (pounds)
Lead 1Hexavalent chromium 0.03Mercury 0.002Cadmium n/a* *Assume cadmium content is the average amount found in an automobile Table 4: Average automobile heavy metal content and corresponding percent deduction
mass (pounds) Pavg (%)Lead 1.1 2Hexavalent chromium 0.034 1Mercury 0.002 1Cadmium n/a 1 Problem 3. Economics of Recycling You are the inverse manufacturing (disassembly) engineer for an air conditioning company who is interested in taking back their A/C units for recycling. Your manager presents two scenarios pertaining to disassembly: power tools and hand tools. In general, you know that power tools will cost more to purchase; however, they will help reduce the disassembly time. Hand tools, on the other hand, will cost less to purchase; however, they will extend the disassembly time. Your boss gives you the following data pertaining to the two methods. He wants to know which method to pursue and the profit he will make for recycling 100,000 A/C units. Table 1: Scrap Market Prices (as of May 2006) material unit valueFerrous $150/tonNon-ferrous $0.95/poundHDPE $0.31/poundPET $0.21/poundmixed PET and HDPE $0/pound Table 2: Material listing for one air conditioning unit material mass (kg)Copper 1.50HDPE 3.30PVC 11.50Steel 2.00Aluminum 0.80Rubber 0.11Total 19.21
Disassembly plant information for Scenario A: Hand tools Labor is $15 per hour. Disassembly time is 35 minutes. For 100,000 appliances, the factory has calculated that the energy cost to run the operation is $200 and tools will cost $10,000. Disassembly plant information for Scenario B: Power tools Labor is $15 per hour. Disassembly time is 26 minutes. For 100,000 appliances, the factory has calculated that the energy cost to run the operation is $500 and tools will cost $50,000.
VI. Test Question Solutions Problem 1: The recyclability of the automobile will change depending on the type of plastic used to replace the metal. If the plastics used has a scrap value (PET or HDPE), then this plastic will be recycled as much as the metal. Therefore, the recyclability of the automobile will stay the same. If the plastic used has no scrap value (any other plastic), then this plastic will NOT be recycled, and the recyclability of the automobile will decrease. Problem 2: Scenario A Equation 3: Rf = Ri - Ptotal Equation 1: Ri = (mfluids + mtires + mbattery + mferrous + mnonferrous + mpet + mpe)/mvehicle *100 Ri = (70+45+14.7+870+180+12+4) kg / (1,500) kg *100 Ri = 1,195.7/1,500*100 Ri = 79.7% Ptotal,test (total percent subtraction) = Plead + Pmercury + Phexavalent chromium + Pcadmium Equation 2: Plead, test = (mlead, test)/(mlead, average) * Plead, average Plead, test =2 pounds/(1.1 pounds) *2% = 3.64% Pmercury, test = (mmercury, test)/(m mercury, average) * P mercury, average =0.002 pounds/(0.002 pounds) *1% = 1% P hexavalent chromium, test = (m hexavalent chromium, test)/(m hexavalent chromium, average) * P hexavalent chromium, average =0.015 pounds/(0.034 pounds) *1% = 0.44% Pcadmium, test = (m cadmium, test)/(m cadmium, average) * P cadmium, average =(assume the test car has the average mass of cadmium) =(m cadmium, average)/(m cadmium, average) * P cadmium, average = P cadmium, average =1% Ptotal,test = (3.64+1+0.44+1)% Ptotal,test = 6.08% Rf = Ri - Ptotal = (79.7-6.08)% = 73.62% Rf (Scenario A) = 73.6%
Scenario B Equation 3: Rf = Ri - Ptotal Equation 1: Ri = (mfluids + mtires + mbattery + mferrous + mnonferrous + mpet + mpe)/mvehicle *100 Ri (same as Scenario A) = (70+45+14.7+870+180+12+4) kg / (1,500) kg *100 Ri = 1,195.7/1,500*100 Ri = 79.7% Ptotal,test (total percent subtraction) = Plead + Pmercury + Phexavalent chromium + Pcadmium Equation 2: Plead, test = (mlead, test)/(mlead, average) * Plead, average Plead, test =1 pounds/(1.1 pounds) *2% = 1.82% Pmercury, test = (mmercury, test)/(m mercury, average) * P mercury, average =0.002 pounds/(0.002 pounds) *1% = 1% P hexavalent chromium, test = (m hexavalent chromium, test)/(m hexavalent chromium, average) * P hexavalent chromium, average =0.030 pounds/(0.034 pounds) *1% = 0.88% Pcadmium, test = (m cadmium, test)/(m cadmium, average) * P cadmium, average =(assume the test car has the average mass of cadmium) =(m cadmium, average)/(m cadmium, average) * P cadmium, average = P cadmium, average =1% Ptotal,test = (1.82+1+0.88+1)% Ptotal,test = 4.7% Rf = Ri - Ptotal = (79.7-4.7)% = 75% Rf (Scenario B) = 75% The new design (Scenario B) is better for the environment because it has a higher Rf value (71%) than the previous design scenario A (69.6%). This is mainly due to the heavier weighting of lead (a car with the average amount of lead gets 2% deduction) compared to hexavalent chromium (a car with the average amount of hexavalent chromium only gets a 1% deduction).
Problem 3: Value for scrap material material mass (kg) mass (pounds) unit value ($/pound) $Copper 1.50 3.31 0.95 3.14HDPE 3.30 7.28 0.31 2.26PVC 11.50 25.36 0.00 0.00Steel 2.00 4.41 0.08 0.33Aluminum 0.80 1.76 0.95 1.68Rubber 0.11 0.25 0.00 0.00Total 19.21 42.37 7.40 Scenario A: Cost for dismantling (Hand tools) Labor cost = 35min*hour/60min*$15/hour=$8.75/appliance Total energy and tools cost for 100,000appliances=$200+$10,000=$10,200 Total energy and tools cost for 1 appliance = $10,200/100,000 appliances=
$0.10/appliance Total cost for dismantling 1 appliance = labor cost+energy and tool cost=
=$8.75+$0.10= $8.85 Profit For each A/C unit = Value - cost=$7.40-$8.85=-$1.45/unit For 100,000 A/C units = -$1.45/units*100,000 units = -$145,000 $145,000 will be lost for every 100,000 A/C units processed. Scenario B: Cost for dismantling (power tools) Labor cost = 26min*hour/60min*$15/hour=$6.50/appliance Total energy and tools cost for 100,000appliances=$500+$50,000=$50,500 Total energy and tools cost for 1 appliance = $50,500/100,000 appliances=
$0.51/appliance Total cost for dismantling 1 appliance = labor cost+energy and tool cost=
=$6.5+$0.51= $7.01 Profit For each A/C unit = Value - cost=$7.40-$7.01=$0.39/unit For 100,000 A/C units = $0.39/units*100,000 units = $39,000 $39,000 profit will occur for every 100,000 A/C units processed. Scenario B of using power tools should be used because $39,000 profit will be made for every 100,000 A/C units processed.