Electricity in Life Cycle AssessmentLecture 10: End of Life
Richard Venditti
North Carolina State University Raleigh, NC 27695-8005
Richard_Venditti@ncsu.edu Go.ncsu.edu/venditti
End of Life
• End of life (EOL), in the context of manufacturing and product lifecycles, is the final stages of a product's existence
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Recycled Materials
Raw Materials
Reduce, re-use, recycle.
• Example: want to understand the burdens of using a bag to transport groceries
• Reduce: don’t use a bag, 0 burden/trip • Re-use (life cycle of a bag = 1 burden)
– Use bag once, 1 burden/trip – Use bag twice, 0.5 burden/trip – Use bag 3x, 0.33 burden/trip
• Recycle (to recycle requires 0.4 burdens, arbitrary value for example) – Then for using the bag and recycling once:
( 1 + 0.4 ) / 2 trips = 0.7 burdens/trip
– (data for example only, not meant to represent an actual process)
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Types of waste.
• Biodegradable waste: food and kitchen waste, green waste, paper (can also be recycled).
– Can be broken down, in a reasonable amount of time, into its base compounds by micro- organisms and other living things, regardless of what those compounds may be.
• Recyclable material: paper, glass, bottles, cans, metals, certain plastics, fabrics, clothes, batteries etc.
• Inert waste: construction and demolition waste, dirt, rocks, debris. Will not degrade due to microbial decomposition.
• Waste Electrical and electronic equipment(WEEE) - electrical appliances, TVs, computers, screens, etc.
• Composite wastes: waste clothing, Tetra Packs, waste plastics such as toys. • Hazardous waste including most paints, chemicals, light bulbs, fluorescent
tubes, spray cans, fertilizer and containers • Toxic waste including pesticides, herbicides, fungicides • Medical waste.
Types of waste.
• All waste can not be treated equally • We must be strategic in our end-of-
life decisions for products.
• Also referred to as trash, or rubbish
• Includes packaging, food scraps, grass clippings, sofas, computers, tires and refrigerators, for example.
• Does not include industrial, hazardous, or construction waste.
Trends in U.S. Waste Generation
EPA: Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2012
Trends in U.S. Waste Recycling
Current U.S. waste treatment
136 million tons
• Residential waste (houses and apartments): 55-65% of total MSW generation
• Commercial and institutional locations (businesses, schools, government, offices, hospitals…): 35-45%
Materials in MSW?
• Dominated by organic matter, biodegradable
• Organic matter or organic material, natural organic matter, NOM is matter composed of organic compounds that has come from the remains of organisms such as plants and animals and their waste products in the environment
Durable vs non-durable goods. • A durable good or a hard good is a good that does not
quickly wear out, or more specifically, one that yields utility over time rather than being completely consumed in one use.
• Examples: Bricks, refrigerators, cars, or mobile phones, cars, household goods (home appliances, consumer electronics, furniture, etc.), sports equipment, and toys.
• Nondurable goods or soft goods (consumables) are immediately consumed in one use or ones that have a lifespan of less than 3 years.
• Examples: cosmetics and cleaning products, food, fuel, beer, cigarettes, medication, office supplies, packaging and containers, paper and paper products, personal products, rubber, plastics, textiles, clothing and footwear.
Source: Wikipedia
Recycling Rates of Selected Products
Adopted from EPA 2011 MSW Facts and Figures
Products with highest % recovery.
• Lead acid batteries, 96% • Corrugated boxes, 85% • Newspapers, 72% • Steel packaging, 69% • Major appliances, 65% • Yard trimmings, 58% • Aluminum cans, 50% • Mixed paper, 45%
Source: Wikipedia
Landfill: a place to dispose of refuse and other waste material
by burying it and covering it over with soil
Landfill Cross Section (simplified)
Cover System
Morton Barlaz, CE, NCSU
+ emissions associated with construction, operation, post-closure and leachate treatment - avoided emissions from energy recovery - carbon storage
Notice: CO2 emissions from decay are not counted (biogenic).
Fugitive methane emissions = CH4 prodn. * (100- % collected) * (100- % oxidized)
Morton Barlaz, CE, NCSU
Carbon Footprint
"the total set of greenhouse gas emissions caused by an organization, event, product or individual."
Carbon Footprint CO2e = fugitive methane emissions
+ emissions associated with construction, operation, post-closure and leachate treatment - avoided emissions from energy recovery - carbon storage
Notice: CO2 emissions from decay are not counted (biogenic).
Fugitive methane emissions = CH4 prodn. * (100- % collected) * (100- % oxidized)
Morton Barlaz, CE, NCSU
Biodegradable Substrates • Paper, yard waste and food waste are
comprised of cellulose and hemicellulose • These compounds are converted to CH4 and
CO2 by bacteria under anaerobic conditions • Several groups of bacteria are involved • Bacteria: ubiquitous one-celled organisms,
spherical, spiral, or rod-shaped and appearing singly or in chains, comprising the Schizomycota, a phylum of the kingdom Monera (in some classification systems the plant class Schizomycetes), various species of which are involved in fermentation, putrefaction, infectious diseases, or nitrogen fixation. (dictionary.reference.com)
Morton Barlaz, CE, NCSU
– Climate, surface hydrology, pH, temperature, operations
Exerts an influence on:
– Gas composition and volume
Morton Barlaz, CE, NCSU
Reactor Data: Methane Yields Mg = 1 tonne, m3 CH4 about .6 kg
(C6H10O5)n + nH2O 3n CO2 + 3n CH4→
(C5H8O4 )n + nH2O 2.5n CO2 + 2.5n CH4→
Cellulose:
Newsp rin
t Offic
e OCC
74.3
217.3
152.3
84.4
62.6
144.4
127.6
30.6
56.8
300.7
152.9
200.7
31.53
7.5
6.3
73.4
6.6
4.6
C footprint Chart
Divide by 2 million to covert to per Mg; multiply by 1000 to covnert to kg
Mg based on 20 years at 100,000 Mg/yr
kg CO2-e per Mg waste
Construction
Sheet3
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Methane Production Rate Curve for One Year of Waste
Based on 286,000 short tons of refuse at time zero and Lo = 1.5 ft3/wet lb (93.5 m3/wet Mg)
0.00E+00
5.00E+05
1.00E+06
1.50E+06
2.00E+06
2.50E+06
3.00E+06
Time (Yr)
M et
ha ne
R at
e (m
3/ yr
Year
% decrease @50 yrs
% decrease @80 yrs
59.1247063911
60.7666148932
58.9675800211
58.8957454676
70.1362238945
64.9201065852
69.2453724394
65.7302086625
65.6311070699
60.5240982453
69.9072962313
58.2468965464
Other impacts: Toxic liquids consisting of paints, cleaning chemicals, solvents.
Effect wildlife.
Land take
Odor
Unsightly
Others….
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First in 1885 in NY, NY – Recognized mercury and dioxin emissions – Clean Air Act 1970s and Maximum Achievable Control
Technology (MACT, 1990s), many plants retrofitted or shut down
Economics Plant costs 100-300 million dollars Plants about 500-3000 tons per day Receive tipping fees Revenue from energy Revenue from ferrous and non ferrous scrap Carbon credits?
Waste To Energy
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A typical WTE plant generates about 550 kilowatt hours (kWh) per ton of waste. At an average price of four cents per kWh, revenues per ton of solid waste would be $20 to $30.
Source – Is It Better to Burn or Bury Waste for Clean Energy Generation? (PDF)
Typically provide a 75% weight reduction and 90% volume reduction
http://www.worldbank.org/urban/solid_wm/erm/CW G%20folder/Waste%20Incineration.pdf
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Source: afandpa.org, 2011
• Single stream recycling: a system in which all paper fibers, plastics, metals, and other containers are mixed in a collection truck, instead of being sorted by the depositor into separate commodities (newspaper, paperboard, corrugated fiberboard, plastic, ... (Wikipedia)
• Sorted stream recycling
An example: Paper Recycling
• Collected from municipalities, and from individual sources
• Brokers collect, sort, bale and re-sell to recyclers
• The paper is slushed into water, separating fibers, pulping
• Contaminants are removed – Screening – Centrifugation – Washing – Bleaching – Others
• Fibers are then re-made into paper
Source: afandpa.org, 2011
Record high 66.8% RR. Paper purchases declined (2.3 million tons) while recovered paper increased 1.3 million tons. Source: afandpa.org, 2012
Paper/board Recovery Rate in the US:
Source: afandpa.org, 2012
Source: afandpa.org, 2012
19 MMT used domestically, 8 MMT exported, Purchases increased 7.2% in 2010, Recovered OCC increased by 11.2% Source: afandpa.org, 2012
Recovery of Corrugated Containers (OCC)
Includes ONP, uncoated mechanical, and coated ONP inserts. 7.5% decrease in consumption of ONP Source: afandpa.org, 2012
Recovery of Old Newspapers (ONP)
Purchases of PW Papers declined by 5%. Source: afandpa.org, 2012
Recovery of Printing-Writing Papers
Carbon footprint
(AF&PA)
Source: NCASI
54.8% to Landfill
Methane
Paper product Recovery Landfill* Burning and energy recovery*
Office paper 71.8% 23.0% 5.2% Catalog 32.7% 54.8% 12.5% Telephone directory
19.1% 65.9% 15.0%
Magazine 38.6% 50.0% 11.4% * Landfill and burning and energy recovery ratios are based on U.S. average for all municipal solid waste in 2006 (81.4% landfilled, 18.4% incinerated).
Table 4-5. End-of-Life of Printing and Writing Paper Products
Life Cycle Inventory: End of Life: Carbon in Products • How much carbon exists in products. Needed for end of life and carbon storage in products. • Half life, number of years for the existing paper in use to halve itself • C permanently stored (in landfills)
Product Carbon content
(fraction) Half-life (years)
Carbon permanently stored
(fraction) bleached kraft board 0.50 2.54 0.12 bleached kraft paper (packaging & industrial)
0.48 2.54 0.61
coated mechanical 0.50 2.54 0.85 coated woodfree 0.50 2.54 0.12 average containerboard 0.50 2.54 0.55 newsprint 0.46 2.54 0.85 recycled boxboard 0.50 2.54 0.55 recycled corrugating medium 0.50 2.54 0.55
How important is end of life?
-1000 -500 0 500 1000 1500 2000 2500 3000 3500 4000
Carbon footprint (kg CO2 eq./BoC)
Total emissions, including transport (kg CO2 eq./BoC):
Of which, total transport (includes all transport components):
Emissions from fuel used in manufacturing (including transport)
Emissions from purchased electricity and steam
Emissions from wood and fiber production (including transport)
Emissions from other raw materials (including transport)
Emissions from manufacturing wastes
Emissions from product transport
Carbon in products in use (kg CO2 eq./BoC)
Carbon in landfills from products at end of life (kg CO2 eq./BoC)
Carbon in mill landfills from manufacturing wastes (kg CO2 eq./BoC)
Ctd Mech
Ctd Free
Fuel Mfg End of Life
Paper Recycling: Other environmental impacts (avoid parts thinking):
Life Cycle Inventory: End of Life
• Allocations in recycling.
Closed and Open Loop Recycling: • Closed loop: material or products are returned to the same
system after use and used for the same purpose again (Baumann, Tillman, 2004)
• Open loop: a product is recycled into a different product
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Production of P Use of Product A Disposal
Production of Product B Disposal
Recover
Recover
Two Main Allocation Situations:
• Recycling Allocation: a virgin product is recycled or re- used in a subsequent life – There exists operations that are required by the virgin and the
recycled products (shared operations) – Example shared operations: virgin raw material production,
final disposal – Many ways to allocate the burdens of the common operations
between virgin and recycled products
• Open loop recycling allocation is the most controversial issue in LCA currently!!!!
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Allocation Methods in LCA: • Example: virgin paper recycled twice and then disposed.
Closed loop recycling example with products P1, P2, and P3.
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End of life (W3)
Allocation Methods in LCA: • Example: virgin paper recycled twice and then
disposed. Closed loop recycling example.
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Collect/transp Recycle Process
Shared Operation
Potentially Shared
CO2e ton/ton product .15 1.50 .12 1.68 .12 1.68 1.25
Table 7. Net GHG of office paper from various life cycle stages from the Paper Task Force (2002, pg. 132), waste management is 80/20 landfill/incinerate.
Allocation Methods in LCA: • Choice of allocation method determines whether virgin or recycled
products are promoted: • Recycled result is the average of products 2 and 3.
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0
1000
2000
3000
4000
5000
6000
7000
Quality Loss RMAGWT
Emissions • Single stream recycling • Steps in Paper
Recycling • Recovery Rate • Closed loop recycling • Open loop recycling • Shared operations • Allocation
• End of Life • Waste management
hierarchy • Biodegradable waste • Inert waste • WEEE • Hazardous waste • Municipal solid waste • Durable goods • Non-durable goods • Recycling • Waste to Energy • Waste to Energy Tradeoff
Environmental Life Cycle AssessmentPSE 476/WPS 576Lecture 10: End of LifeRichard Venditti
End of Life
Current U.S. waste treatment
Products with highest % recovery.
Landfill: a place to dispose of refuse and other waste material by burying it and covering it over with soil
Landfill Cross Section (simplified)
Carbon Footprint
Carbon Footprint
Carbon Footprint
Biodegradable Substrates
Refuse Decomposition
Reactor Data: Methane YieldsMg = 1 tonne, m3 CH4 about .6 kg
Methane Production Rate Curve for One Year of Waste
Other impacts:
Waste To Energy: Trade-off
Waste To Energy
Waste to Energy
Slide Number 40
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End of Life Example: Catalog PaperCarbon footprintReference:American Forest and Paper Association(AF&PA)
End of life: Catalog Paper
Slide Number 48
Life Cycle Inventory: End of Life: Carbon in Products
How important is end of life?
How important is end of life?(ctd free = catalog)
Paper Recycling: Other environmental impacts (avoid parts thinking):
Life Cycle Inventory: End of Life
Closed and Open Loop Recycling:
Two Main Allocation Situations:
Allocation Methods in LCA:
Allocation Methods in LCA:
Allocation Methods in LCA: