Material Flow Perspective of Pollution Prevention:

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Material Flow Perspective of Pollution Prevention

• If pollution is caused by material flows, its
  prevention is also a material issue
• There are essentially three ways to reduce or
  prevent pollution
• Increase resource productivity (use less to
  achieve the same function)
• Material/process substitution (different
  material/process to achieve the same)
• Reuse recycling (use material and value-added
  over and over)

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Dematerialization examples

• Advanced High Strength Steels (AHSS) in
  automotive applications (25 weight reduction)
• Mass reduction of beverage containers
• Continuous casting technology in metals
  production
• Drip lines instead of sprinklers for irrigation
• Spaceframe design concept
• Miniaturization in the electronics industry
  (e.g. precious metal content in consumer
  electronics)

Dematerialization typically has a natural
economic driver and is also often done in
conjunction with material substitution.
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Material substitution examples

• Steel versus aluminum versus plastics versus
  composites in automotive
• Steel versus concrete versus timber in
  construction
• Glass versus steel versus aluminum versus PET
  versus laminated cardboard in packaging
• MTBE instead of lead as oxygenate in automotive
  fuels
• Bio-based plastics versus petroleum-based
  plastics (e.g. polylactic acid)
• Lead-based solder versus lead-free solder (e.g.
  tin silver copper antimony alloy,
  
  tin copper selenium alloy, etc.)

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Material substitution Case study 1 Lead-free
solder
Background Electronics industry consumes around
90 Kt pa of lead-based solder
(60Sn-40Pb), 25-50 of which ends up as
process waste Issue Toxicity of lead
(EU ROHS Directive 2002/95/EC bans lead in
EEE) Substitute Lead-free solder (e.g. the
one announced by Sony in 1999
93.4 tin, 2 silver, 4 bismuth, 0.5 copper
and 0.1 germanium)
Source Graedel Allenby (2003) Industrial
Ecology, Prentice Hall
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Material substitution Case study 1 Lead-free
solder

• Lead-free solder announced by Sony in1999
• 93.4 Sn, 2 Ag, 4 Bi, 0.5 Cu and 0.1 Ge
• New issues
• Production capacity for increased use of
  alloying materials If all solder was based on
  Sonys alloy, world production would increase as
  follows Sn 12, Ag 11, Bi 89, Ge 103
• Bismuth by-product of mining other metal,
  primarily lead
• Depletion of some of the alloying metals

Source Graedel Allenby (2003) Industrial
Ecology, Prentice Hall
6
Material substitution Case study 2 Bio-based
plastics
Background Production of plastics worldwide
consumes around 270 MMT pa of fossil
fuel, 120 MMT as feedstock and another
150 MMT as process energy. Issues
Depletion of fossil fuels
Additives (plasticizers, stabilizers, flame
retardants, blowing agents) Lack of
biodegradability (growing and persistent solid
waste stream) Substitute Bio-based
polymers (e.g. PLA or PHA) Examples
NatureWorks (Cargill Dow Polymers, USA)
packaging films, bottles,
textile fibers based on polylactic acid from
maize fermentation
GreenFill (GreenLight Products, UK) loosefill
packaging derived from
wheat starch Mater-Bi
(Novamont, Italy) films, tableware, nappies
based on a copolymer of
maize starch and polycaprolactone
(PotatoPak, UK) supermarket display
trays based on potato starch
(Rodenburg Polymers, NL) packaging
materials from potato starch
NatureFlex (Surface Specialities, UK)
cellulosic packaging films
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Material substitution Case study 2 Bio-based
plastics
American Society for Testing and Materials (ASTM)
definition Biodegradable plastic a degradable
plastic in which the degradation results from
the action of naturally occurring microorganisms
such as bacteria, fungi and algae. The first
compostable logo for cutlery went to Nat-Ur. The
Biodegradable Products Institutes (BPI) symbol
demonstrates that the product meets the ASTM
D6400 Specifications for Compostable Plastics.
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Material substitution Case study 2 Bio-based
plastics

• European Standard for biodegradability is EN
  13432 (2000)
• Biodegradation over 90 of the organic material
  converted to CO2 in 6 months under conditions
  of controlled composting (ISO14855)
• Disintegration over 90 of original mass
  disintegrated in 3 months
• Ecotoxicity test results from aquatic and
  terrestrial organisms (Daphnia magna,
  worm test, germination test) as for
  reference compost
• Absence of hazardous chemicals

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Material substitution Case study 2 Bio-based
plastics

• In an LCA the cradle-to-gate GHG emissions of
  polyhydroxyalkanoate (PHA), a bio-polymer
  extracted from genetically modified corn, were
  compared to those of polyethylene (PE).
• New issues
• The extraction process of PHA from corn is quite
  energy intensive.
• If the extraction energy comes from fossil
  fuels, the cradle-to-gate GHG emissions of PHA
  are higher than those of PE.
• Cradle-to-gate GHG emissions of PHA are lower
  than those of PE only if the stover is burned
  for energy generation, i.e. no fossil fuels are
  required for PHA extraction.

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Reuse and RecyclingFrom Supply Chains to Supply
Loops
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From supply chains to supply loops
Traditional supply chains end with the sale and
delivery of the final product
Raw materials mining
Primary materials production
Component manufacture
Final product assembly
Product sale and delivery
Lee Billington, for example, define a supply
chain as a network of facilities that
procure raw materials, transform them into
intermediary goods and then final products, and
deliver the products to customers through a
distribution system.
Product demand use
End-of-life product disposal
What happens to the product after sale and
deliveryis of no concern for supply chain
managers
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Supply loops divert end-of-life products from
landfill and reprocess these products, their
components or their materials into secondary
resources which replace primary resources in
forward supply chains.
Raw materials mining
Primary materials production
Component manufacture
Final product assembly
Product sale and delivery
Product demand use
Component re- processing
Product re- processing
Materials re- processing
End-of-life product disposal
Eol product collection inspection
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A supply loop is constrained when it is not able,
for technical or economic reasons, to reprocess
all targeted arising end-of-life products into
secondaryoutput that is marketable a above-cost
prices.
Raw materials mining
Primary materials production
Component manufacture
Final product assembly
Product sale and delivery
Product demand use
Component re- processing
Product re- processing
Materials re- processing
End-of-life product disposal
Eol product collection inspection

• The reasons can be
• Limited collection of end-of-life products

• Limited feasibility of reprocessing

• Limited market demand for the reprocessed
  secondary resources

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Supply Loops Environmental Benefits
2.
1.
Primaryproduction
Disposal
Use
Collection reprocessing

• Diversion of product or process waste from
  landfill or incineration by collecting them for
  economic value recovery via reprocessing.
• Generation of secondary resources from product
  or process waste and displacement of primary
  resources, i.e. materials, components products.

The environmental benefits from displacement are
frequently more significant than the benefits
from avoided landfill / incineration.
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Supply Loops Environmental Performance
Examples
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Supply Loops - Material Recycling Definitions
Primary material production
Product manufacturing
Use
Disposal
Material reprocessing
Secondary output
eol recycling efficiency rate Eol collection
rate Eol reprocessing yield
Available secondary resource
Collected secondary resource
Available secondary resource
Secondary output
Collected secondary resource
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Supply Loops - Material Recycling - Definitions
Primary material production
Product manufacturing
Use
Disposal
Material reprocessing
eol recycling efficiency rate Eol collection
rate Eol reprocessing yield
Total recycling input rate Total recycling
efficiency rate
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Example Copper Flows in North America in 1994
(in kt / y)
Import / Export
Old Scrap 190
Semis, Finished Products 17
Concentrate, Blister, Cathode 325
Ingots 3
Production Mill, Smelter, Refinery
Fabrication Manufacturing
Use
Waste Management
Discards 1410
Cathode 3270
Prod. Cu 2640
1920
3
Stock
Stock
Prod. Alloy 690
730
140
Ore 3130
710
New Scrap
180
330
Old Scrap
Landfilled Waste, Dissipated
Tailings Slag 365
Source CIE, Yale
Environment
Lithosphere
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Supply Loops Material Recycling Infinite
Cycles
Primarymaterials production
End-of-life product disposal
Materials use
Collection recycling
collection rate for each cycle
recycling efficiency rate for each cycle
recycling yield for each cycle
Question How much recycled material do I get
from m primary material?
Total amount of material (assuming unlimited
recyclability) is Summing this series gives of
which
is secondary (recycled)
material. Overall recycling efficiency rate (
for infinite cycles)
Example r 0.66, P 1kg M 3kg P 1kg
primary S 2kg secondary
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Supply Loops Basic Environmental Performance
Production Eprod
End-of-life disposal Edisp
Use Euse
Overall recycling efficiency rate
Collection Ecoll
Reprocessing Erepro

• Life cycle impact (of a chosen environmental
  impact category)
• Without recycling
• With recycling
• Change in life cycle impact
• Recycling reduces life cycle impact if

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Conclusions
In supply loops the additional environmental
impacts ofcollection and reprocessing need to be
traded off against the saved environmental
impacts of primary production and disposal. In
constrained supply loops more is not always
better. Supply loops may haveenvironmentally
optimal collection rates anywhere between 0 and
100.

• In product systems with reuse the environmental
  impacts of the processes need to be assessed and
  managed in an integrated way withthe three basic
  supply loop constraints
• the access to end-of-life products
• the feasibility of the reprocessing
• and the market demand for the secondary resources

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Homework for Thursday, 13 November Assignment
3 (posted on course website) Due date
Tuesday, November 18 Reading for Tuesday, 11
NovemberGeyer Jackson (2004) Supply loops
and their constraints The industrial ecology of
recycling and reuse, California Management
Review, 46(2) 55-73Davis et al. (2007)
Time-dependent MFA of iron and steel in the UK,
Resources, Conservation Recycling, 51(2007)
118-140(is posted on course website)