Environmental Life Cycle Assessment PSE 476/WPS 576
Lecture 10: End of Life
Richard Venditti
Fall 2016
Richard A. Venditti Forest Biomaterials North Carolina State University Raleigh, NC 27695-8005
1 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
Recycled Materials
Energy Energy Energy Energy Energy
Raw Production Transportation Materials Use Disposal Recycle
Waste Waste Waste Waste Waste Emissions to Emissions to Emissions to Emissions to air and water air and water air and water air and water2 Waste Hierarchy
http://www.epa.gov/wastes/nonhaz/municipal/hierarchy.htm 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)
4 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. Municipal solid waste?
• MSW: everyday items that are discarded by the public • 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
20 million tons
%
29 million tons %
% 136 million tons
% Total: 250 million tons
65 million tons 10 Adopted from EPA 2011 MSW Facts and Figures Source of MSW?
• 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 Products in MSW? (cont. next pg) Products, Million tons, 2012 (cont. from prev pg) 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) Monitoring Gas Collection Wells Vegetation Cover System
Waste
Leachate Collection System Liner System
Water Table
Morton Barlaz, CE, NCSU Carbon Flow In Landfills Emissions CO2, Energy Offset
Capture Fugitive
Gas (CH4, CO2, VOCs)
Decomposing Waste Residential Industrial Commercial Biosolids Stored Carbon
Morton Barlaz, CE, NCSU Leachate (CO2, VOCs) 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 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 26 Refuse Decomposition
. Refuse decomposition is affected by: – Climate, surface hydrology, pH, temperature, operations . Exerts an influence on: – Gas composition and volume – Leachate composition
27 Morton Barlaz, CE, NCSU Reactor Data: Methane Yields Mg = 1 tonne, m3 CH4 about .6 kg
350 300 /dry Mg) /dry
4 Cellulose250 :
CH 200 3 150 (C6H10O5)n + nH2O → 3n CO2 + 3n CH4 100
yield (M 50 4 CH Hemicellulose0 :
Office OCC Food OSB Grass Leaves (CNewsprintH O ) + nH BranchesO → 2.5nHardwood COSoftwood + 2.5n CH 5 8 4 n Coated Paper2 Plywood2 (SW) Particle Board 4
Medium Density Fiberboard Morton Barlaz, CE, NCSU Methane Production Rate Curve for One Year of Waste
3.00E+06
2.50E+06
2.00E+06
1.50E+06
1.00E+06 Methane (m3/yr) Rate
5.00E+05
0.00E+00 0 25 50 75 100 Time (Yr) CopyrightBased Morton on A. 286,000 short tons of refuse at time zero Barlaz,and NC State Lo = 1.5 ft3/wet lb (93.5 29m3/wet Mg) University Other impacts:
Toxic liquids consisting of paints, cleaning chemicals, solvents.
Effect wildlife.
Land take
Odor
Unsightly
Others…. Waste To Energy
. 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?
31 Morton Barlaz, CE, NCSU Waste To Energy
32 Waste To Energy: Trade Off
. 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
33 Waste To Energy: Trade-off
. Gas emissions . Solid emissions
34 Morton Barlaz, CE, NCSU Waste To Energy: trade off
35 Waste To Energy
36 Waste to Energy Recycling
• 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
Understanding economic and environmental impacts of single-stream collection systems, Container recycling institute, 2009. Source: afandpa.org, 2011 An example: Paper Recycling
• Paper is collected and sometimes sorted • 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 Paper/board Recovery Rate in the US:
Record high 66.8% RR. Paper purchases declined (2.3 million tons) while recovered paper increased 1.3 million tons. Source: afandpa.org, 2012 Recovered and Landfilled Paper
Source: afandpa.org, 2012 Where Recovered Paper Goes:
Source: afandpa.org, 2012 Recovery of Corrugated Containers (OCC)
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 Old Newspapers (ONP)
Includes ONP, uncoated mechanical, and coated ONP inserts. 7.5% decrease in consumption of ONP Source: afandpa.org, 2012 Recovery of Printing-Writing Papers
Purchases of PW Papers declined by 5%. Source: afandpa.org, 2012 End of Life Example: Catalog Paper
Carbon footprint
Reference: American Forest and Paper Association (AF&PA) End of life: Catalog Paper
Source: NCASI 32.7% to Recycle
12.5% Burning with Energy Recovery
Emissions
Methane
54.8% to Landfill
Burnt for Electicity CO2 X % stored as permanent Carbon (100yrs) End of life: Printing and Writing Papers
Table 4-5. End-of-Life of Printing and Writing Paper Products
Burning and Paper product Recovery Landfill* energy recovery* Office paper 71.8% 23.0% 5.2% Catalog 32.7% 54.8% 12.5% Telephone 19.1% 65.9% 15.0% directory 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). 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)
Carbon permanently Carbon content Half-life Product stored (fraction) (years) (fraction) bleached kraft board 0.50 2.54 0.12 bleached kraft paper (packaging & 0.48 2.54 industrial) 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?
Carbon in mill landfills from manufacturing wastes (kg CO2 eq./BoC)
Carbon in landfills from products at end of life (kg CO2 eq./BoC)
Carbon in products in use (kg CO2 eq./BoC) Ctd Mech
Changes in forest carbon (kg CO2 eq./BoC) Ctd Free
Total carbon storage changes (kg CO2 eq./BoC)
Emissions from end of life (including transport)
Emissions from product transport
Emissions from manufacturing wastes
Emissions from other raw materials (including transport)
Emissions from wood and fiber production (including transport)
Emissions from purchased electricity and steam
Emissions from fuel used in manufacturing (including transport)
Of which, total transport (includes all transport components):
Total emissions, including transport (kg CO2 eq./BoC):
Carbon footprint (kg CO2 eq./BoC)
-1000 -500 0 500 1000 1500 2000 2500 3000 3500 4000 How important is end of life? (ctd free = catalog)
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
Production of P Use Product Disposal
Recover
Production of P Use of Product A Disposal Recover
Production of Product B Disposal
55 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!!!!
56 Allocation Methods in LCA: • Example: virgin paper recycled twice and then disposed. Closed loop recycling example with products P1, P2, and P3.
Primary material production (V1)
Production of Recycling of Production of Recycling of Production of Product P1 Product P1 Product P2 Product P2 Product P3 (P1) (R1) (P2) (R2) (P3)
Use of Use of Use of Product P1 Product P2 Product P3 (U1) (U2) (U3)
End of life (W3)
57 Allocation Methods in LCA: • Example: virgin paper recycled twice and then disposed. Closed loop recycling example.
Raw Matl Virgin Prod Collect/transp Recycle Collect/transp Recycle Waste Process Process Mgmt V1 P1 R1 P2 R2 P3 W3 Potentially Potentially Potentially Shared Not Shared Not Shared Shared Shared Shared Shared Operation Operation Operation Operation Operation Operation Operation CO2e Lb/ton 300 3000 230 3350 230 3350 2500 product 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.
58 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.
7000
Paper Task Force Virgin Burden Recycled Burden 6000
5000 Shared Burden
4000
3000 lb CO2eq/ton
2000 Net GHG, Net
1000
0 Cutoff MLWMBR 50/50 Closed Loop Quality Loss RMAGWT Recycling 59 Summary
• Landfill • End of Life • Carbon footprint • Waste management hierarchy • Fugitive Methane • Biodegradable waste Emissions • Inert waste • Single stream recycling • WEEE • Steps in Paper • Hazardous waste Recycling • Municipal solid waste • Recovery Rate • Durable goods • Closed loop recycling • Non-durable goods • Open loop recycling • Recycling • Shared operations • Waste to Energy • Waste to Energy Tradeoff • Allocation