A primer on environmental life-cycle based decision support tools for

sustainable materials management

Ozge Kaplan, Ph.D.

U.S. Environmental Protection Agency

Research Triangle Park, NC

Invited Lecture in “Sustainability Decision Tools” Online Course at Rutgers University

Spring 2018

Agenda

•Brief primer on "LCA"• Definition• Stages (goal and scope; inventory; impact assessment;

interpretation)• Functional unit

•LCA applications: Municipal Solid Waste Decision Support Tool – MSW DST

A Primer on Life Cycle Assessment

LCA is a way to investigate, estimate, and evaluate the environmental burdens caused by a material, product, process, or service throughout its life span.

1. Goal and Scope Definition

2. Inventory Analysis

3. Impact Assessment

4. Interpretation

United Nations Environment Programme. 2002. Evaluation of environmental impacts in life cycle assessment. Meeting report. Available from: http://lcinitiative.unep.fr/default.asp?site=lcinit&page_id=F511DC47-8407-41E9-AB5D-6493413088FB.United Nations Environment Programme. 2011. Global Guidance Principles for Life Cycle Assessment Databases: A Basis for Greener Processes and Products: ‘Shonan Guidance Principles’. Available from: http://www.unep.org/pdf/Global-Guidance-Principles-for-LCA.pdf

Functional unit defines what has been studied,

and links it within the LCA to inputs and outputs.

Also it creates a basis for apples to apples

comparison when more than one product with same

service is compared.

System boundaries define which processes that

should be included in the analysis of a product

system. (see scoping discussion)

LCA can inform

• Differentiate the impacts of two comparable products:

• Consumer products and end of life issues

• plastic versus paper versus glass cups

• Coal versus natural gas for electricity generation

• extraction to processing then final use

• Assess design options for the same product:

• Automobiles

• Steel-dominant material over the years

• Technological change yielded

• use of more plastics and composite materials

• safe alloys increased aluminum

• Fuel economy savings, but full LCA including air-borne and water-borne emissions of each alternative needs to be evaluated for better decision making on relative upstream impacts

LCA can inform…

• Identify which part of the supply chain to focus emission reductions efforts:

• Increasing offshore wind capacity no emissions and life cycle impacts?

• Manufacturing LCA of wind turbines

• O&M of the facility (e.g., servicing boats running on fuel oil or use of small natural gas turbines to compensate load variability)

• Can all contribute LCA emissions, but which ones are most important?

LCA focus: Sustainable materials management

In 2014, U.S. generated 273,116,704 metric tons of municipal solid waste.

• The management of MSW resulted in air-borne and water-borne emissions including criteria air pollutants and greenhouse gases

Of that, 25.7% recycled, 8.9% composted and 12.8% combusted in waste-to-energy facilities, rest is landfilled.

1.8% of total GHG emissions in

the U.S. is attributed to waste sector.

Source: U.S. EPA, DRAFT Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2016. (2018) EPA 430-P-18-001, Available at: https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks

Solid waste management can be complex: many options are interrelated

• Recycling vs. waste-to-energy for recyclable paper and plastics

• Relative benefits of landfilling or composting yard waste if landfill methane is recovered?

• How do the cost and environmental emissions change

• include or exclude a material from our recycling program?

Solid waste industry generated $43.3 Billion in total revenues in 1999a

a: http://www.waste360.com/mag/waste_us_solid_waste

Municipal Solid Waste Decision Support Tool

• Calculates the cost and LCA based environmental trade-offs using either default parameters and/or user-defined objectives and constraints

• Waste management unit process models to estimate emissions inventories and cost

• Optimization of cost and emissions

• Comparative scenario analysis

• Sensitivity and uncertainty analysis

• 1st Generation Tool was released to public in 2012

• Used in over 200 studies by industry, academia, World Bank, NGOs, and state and local governments

• Working on 2nd Generation Version

• Updates to life-cycle based process models

• Incorporates new process models

• Allows analysis of system evolution over time

• Estimate of metrics for cost, LCA environmental and energy tradeoffs, and societal aspects

Project stakeholders

American Forest and Paper AssociationAmerican Iron and Steel InstituteAmerican Plastics CouncilAmerican Public Works AssociationAmerican Society of Mechanical EngineersAssociation of County Commissioners for GeorgiaAssociation of State and Territorial Solid Waste Management OfficialsAudubonBes-Pack, Inc.Browning-Ferris Industries, Inc.Can Manufacturers InstituteChemical Manufacturers AssociationCity of AustinCity of Los AngelesCity of Madison, WICity of PhiladelphiaCity of PortlandCity of San JoseCorporations Supporting RecyclingSanta Barbara County Waste Mgmt DivisionDelaware Solid Waste AuthorityE. Tseng & AssociatesElectronic Industries AssociationElectro-Pyrolysis, Inc.Energy Answers Corporation, Inc. Environment Canada

Environmental Defense FundEnvironmental Industry AssociationsGlass Manufacturing Industry CouncilGlass Packaging InstituteIndiana Institute of RecyclingInstitute of Scrap Recycling Industries, Inc.Integrated Waste Services AssociationInternational City/County Management AssociationInternational Joint CommissionKeep American BeautifulLucas County Solid Waste Management DistrictMinnesota Office of Environmental AssistanceMonterey Regional Waste Management DistrictMSW ManagementNational Association of CountiesNational Conference of State LegislaturesNational Council of the Paper Industry for Air & Stream Improvements, Inc.National Recycling CoalitionNational Resources Defense CouncilNational Solid Waste Management AssociationNew York City Department of Sanitation

New York State Energy Research and Development AuthorityNorth Carolina Department of Environment and Natural ResourcesOgden MartinOwens-Illinois, IncProcter & Gamble CompanyResource Recycling Systems, Inc.Solid Waste Association of North AmericanSound Resource Management GroupSouth Carolina Institute for EnergyState of FloridaState of GeorgiaState of IowaState of New HampshireState of PennsylvaniaState of WisconsinSteel Recycling InstituteThe Aluminum AssociationThe City of San DiegoThe Coca-Cola CompanyUnion CarbideU.S. Conference of MayorsU.S. NavyVirginia Association of CountiesWaste Industries, Inc.Waste Management, Inc.

Access to MSW DST

• Fully functional (i.e., all process models and optimization routine) MSW DST is available for wide distribution

• Downloaded through web at: https://mswdst.rti.org

• Site includes:

• Basic information

• Tutorials

• Technical documentation

• Research papers

Goal and scope definition

• Define the functional unit for the purposes of consistent comparison

• Ton of waste set out for collection• Ton of product, widget made…

• Consider municipal solid waste (MSW) as defined by the US EPA

• residential and commercial waste• no industrial, agricultural waste

• One ton of MSW as set out for collection• focus on waste a municipality manages

• excludes backyard composting• Within the scope, define waste composition,

duration/period, environmental regulatory issues, waste authority jurisdictions

Waste generation and composition

Categorized by residential, multifamily and commercial

Composition includes:

• Plastics (t-HDPE, p-HDPE, PET beverage, other, non-recyclable)

• Paper (old newsprint, old corrugated cardboard, office paper, phone books, old magazines, 3rd class mail, other, non-recyclable)

• Miscellaneous

• User defined mixtures of paper, plastic and glass

• Yard Waste (grass, leaves, branches)• Food Waste• Ferrous (cans, other, non-recyclables• Aluminum (cans, other, non-recyclable)• Glass (clear, brown, green, non-

recyclable)

Life cycle inventory analysis

• Includes defining the boundaries of the system being analyzed

• Allocation of emissions to the components processed in a specific unit operation

• Collection: allocation by volume

• MRF: ferrous metals recovery

• Landfill: gaseous emissions due to biodegradable compounds only

• Creating inventory of flows (i.e., mass, energy, fuels, emissions) per process model

• Data either can be collected or generated through process models

Waste flow

Fuels

Electricity

Landfill process model to compute gas production and

operational emissions

Cost, life-cycle inventory outputs

LCI for electric grid

Pre-combustion LCI for fuels

Illustrative LCI for landfill process: $ per ton of glass, lb CO2 per ton of paper, BTU per ton of grass…

• Cost & Energy

• Gaseous: CO2-f, CO2-b, PM, NOx, SOx, CH4, Greenhouse equivalents (GHE)

• Liquid: BOD, COD, SS, NH3, PO4, oil, 10 metals

• Solid Waste: Five categories

Life cycle inventory: limitations and key considerations

• Proper LCI requires uniform data across the processes analyzed

• 5 + non data ≠ 5

• Results will be driven by

• Boundaries and scope of system

• Input data assumptions

• Geographic differences

• Scenario and sensitivity analysis is key to understanding broad impacts

Process models and SWM system integration

• A model of a solid waste unit operation to calculate the cost and life cycle inventory (LCI) of emissions as a function of:

• waste quantity, waste composition, user defined, site-specific input data

• Each Major Solid Waste Unit Operation• collection• MRFs (sorting plants)• transfer stations• composting (yard and mixed waste)• waste-to-energy• landfills (conventional, bioreactor, ash)• refuse-derived fuel

Process Models: Typical Input Data

• Collection Model• collection frequency• truck capacity• waste density• time at each stop (location)• houses per stop• time between stops

• Landfill• gas generation rate• gas management (3 periods)

• vent, flare, energy recovery

• gas collection efficiency• waste density• leachate generation as % of

rainfall

Supporting process models

•Each Supporting Unit Operation• electrical energy

• consumption and recovery

• long distance transportation• remanufacturing

• the conversion of recyclable materials into new products

Remanufacturing – materials recovery

• When recyclables are converted to new products:

• resource consumption and emissions are associated with recyclables collection and remanufacture

• some manufacture from virgin is avoided

• The model accounts for the difference:

Offset Analysis:recycle process emissions - virgin process emissions

Energy recovery

• When energy is recovered:• landfill gas• waste-to-energy• refuse/process derived fuel

• An equivalent amount of energy is avoided• national or regional grid• default or use-modified fuel mix

• different fuel mix for generation and avoided production

What does integrated system mean?

Yard waste collection

Mixed waste collection

Commingled recyclables collection

Presorted recyclables collection

…

Ash Landfill

Landfill

Composting

Material Recovery Facility

Waste-To-Energy

…

Remanufacturing processes for recyclables

Processes for fuels and energy

Electric Grid

• Represent all feasible flow paths while preserving mass balance• Solved for an objective function such as least cost or minimize a particular emissions

• meeting specified constraints such as block or require a unit operation or recycling requirements

Each process model generates $ per ton of glass, lb CO2 per ton of paper, BTU per ton of grass, etc. factors

Illustrative Example

• https://mswdst.rti.org/tutorial.htm

Burn vs. bury study

* Note that these values are absolute LCI emissions and do not include the offsets due to avoided electricity production.

Comparison on a per MWh of electricity generated

• For even the most optimistic assumptions about LFGTE, the

net life-cycle environmental tradeoffs is 2 to 6 times the

amount of GHGs compared to WTE.

• In addition, WTE also produces lower NOx emissions than

LFGTE, whereas SOx emissions depend on the specific

configurations of WTE and LFGTE.

• GHGs for WTE ranged from 0.4 to 1.4 MTCO2e/MWh

whereas the most aggressive LFGTE scenario resulted

in 2.3 MTCO2e/MWh (landfill carbon storage not

included).

Kaplan, P. O.; DeCarolis, J.; Thorneloe, S., Is It Better To Burn or Bury Waste for Clean Electricity Generation? Environmental Science & Technology 2009, 43 (6), 1711-1717.

Burn vs. bury study

• On a per ton of MSW basis, the comparison showed results still in favor of WTE, however, the results are more likely influenced by sensitivities around:

• waste composition

• split between biogenic and fossil components

• Landfill gas collection efficiency

• WTE plant efficiency etc.

• The ranges shown in the graph represent sensitivities around above mentioned parameters

• The main waste items contributing to landfill gas emissions are food and yard waste (organic and decomposable), though main waste items contributing to WTE carbon emissions are plastics and other high heating value commodities. • Note that these values are absolute LCI emissions and do not include the offsets due to

avoided electricity production.

Comparison on a per ton of MSW

WTE is on average 6 to 11 times more efficient at recovering energy from wastes than landfills.

Kaplan, P. O.; DeCarolis, J.; Thorneloe, S., Is It Better To Burn or Bury Waste for Clean Electricity Generation? Environmental Science & Technology 2009, 43 (6), 1711-1717.

PublicationsBarlaz M.A., Camobreco V., Repa E., Ham R.K., Felker M., Rousseau C. & Rathle J. (1999a) Life-Cycle Inventory of a Modern Municipal Solid Waste Landfill,

Sardinia 99, Seventh International Waste Management and Landfill Symposium, Vol III, 337-344, Oct 4-8.

Barlaz M.A., Ranjithan S.R., Brill E.D. Jr., Dumas R.D., Harrison K.W. & Solano E. (1999b) Development of Alternative Solid Waste Management Options: A Mathematical Modeling Approach, Sar 99, Seventh Int. Waste Management & Landfill Symp., Vol I, 25-32, Oct 4-8.

Barlaz, M. A., Kaplan, P. O, S. R. Ranjithan and R. Rynk, 2003, "Evaluating Environmental Impacts of Solid Waste Management Alternatives, Part I", Biocycle, Sept., p. 60 - 66.

Barlaz, M. A., Kaplan, P. O, S. R. Ranjithan and R. Rynk, 2003, "Evaluating Environmental Impacts of Solid Waste Management Alternatives, Part II" Biocycle, Oct., p. 52 - 56.

Camobreco, V.; Ham, R.; Barlaz, M.; Repa, E.; Felker, M.; Rousseau, C.; Rathle, J., Life cycle inventory of a modern municipal solid waste landfill. Waste Management and Research 1999, 17 (6), 394-408.

Ecobalance (1999) Life-Cycle Inventory of a Modern Municipal Solid Waste Landfill; Prepared for the Environmental Research and Education Foundation, Washington, D.C.

Ham R.K. & Komilis D. (2003) A Laboratory Study to Investigate Gaseous Emissions and Solids Decomposition During Composting of Municipal Solid Waste, EPA-600/R-03/004.

Harrison, K. W.; Dumas, R. D.; Solano, E.; Barlaz, M. A.; Brill, E. D.; Ranjithan, S. R., (2001) Decision support tool for life-cycle-based solid waste management. J. Comput. Civil. Eng. 15 (1), 44-58.

Harrison, K. W.; Dumas, R. D.; Barlaz, M. A.; Nishtala, S. R., A life-cycle inventory model of municipal solid waste combustion. J Air Waste Manage 2000, 50 (6), 993-1003.

Jambeck, J., Weitz, K.A., Solo-Gabriele, H., Townsend, T., Thorneloe, S., (2007). CCA-treated Wood Disposed in Landfills and Life-cycle Trade-Offs With Waste-to-Energy and MSW Landfill Disposal, Waste Management , Vol 27, Issue 8, Life-Cycle Assessment in Waste Management.

Kaplan, P. O.; Barlaz, M. A.; Ranjithan, S. R., A Procedure for Life-Cycle-Based Solid Waste Management with Consideration of Uncertainty. Journal of Industrial Ecology 2004, 8 (4), 155-172.

Publications (cont’d)Kaplan, O.; Ranjithan S.R.; Barlaz M.A. (2006) The Application of Life-Cycle Analysis to Integrated Waste Management Planning for the State of Delaware, Prepared for Delaware Solid

Waste Authority, May.

Kaplan, P. O.; Ranjithan, S. R.; Barlaz, M. A., Use of Life-Cycle Analysis To Support Solid Waste Management Planning for Delaware. Environmental Science & Technology 2009, 43 (5), 1264-1270.

Kaplan, P. O.; DeCarolis, J.; Thorneloe, S., Is It Better To Burn or Bury Waste for Clean Electricity Generation? Environmental Science & Technology 2009, 43 (6), 1711-1717.

Solano, E.; Ranjithan, S. R.; Barlaz, M. A.; Brill, E. D., Life-cycle-based solid waste management. I: Model development. JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE 2002, 128 (10), 981-992.

Solano, E.; Dumas, R. D.; Harrison, K. W.; Ranjithan, S. R.; Barlaz, M. A.; Brill, E. D., Life-cycle-based solid waste management. II: Illustrative applications. JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE 2002, 128 (10), 993-1005.

Thorneloe, S.A., Weitz; K.A; Jambeck, J. (2007) Application of the U.S. Decision Support Tool for Materials and Waste Management, Waste Management , Vol 27, Issue 8, Pages 1006-1020, Life-Cycle Assessment in Waste Management.

Thorneloe S.A., Weitz K.A., Barlaz M. & Ham R.K. (1999a) Tools for Determining Sustainable Waste Management Through Application of Life-Cycle Assessment: Update on U.S. Research, Sardinia 99, 7th International Landfill Symposium, Vol V, 629-636, Oct 4-8.

Thorneloe S.A. & Weitz K.A. (2001) U.S. Case Studies using MSW DST. Proceedings Sardinia 2001, 8th Int. Waste Management & Landfill Symposium, Cagliari.

Thorneloe S.A. & Weitz K.A. (2003) Holistic Approach to Environmental Management of Municipal Solid Waste. Proceedings Sardinia 2003, 9th International Waste Management and Landfill Symposium, CISA publisher, Cagliari.

Thorneloe, S.A. & Weitz K.A. (2004) Sustainability and Waste Management. Proceedings from Sustainable Waste Management, Waste Management Association of Australia, Nov 24-26, 2004, Melbourne, Australia.

Weitz K.A., Thorneloe S.A., Nishtala S.R., Yarkosky S. & Zannes M. (2002) The Impact of Municipal Solid Waste Management on GHG Emissions in the United States, Journal of the Air and Waste Management Association, Vol 52, 1000-1011.

Weitz, K.A. (2003) Life-Cycle Inventory Data Sets for Material Production of Aluminum, Glass, Paper, Plastic, and Steel in North America, https://mswdst.rti.org

Available documentation• Collection Model

• Dumas, R. D. and E. M. Curtis, 1998, “A Spreadsheet Framework for Analysis of Costs and Life-Cycle Inventory Parameters Associated with Collection of Municipal Solid Waste,” Internal Project Report, North Carolina State University, Raleigh, NC. (https://webdstmsw.rti.org/docs/Collection_Model_OCR.pdf )

• Transfer Stations

• https://webdstmsw.rti.org/docs/Transfer_Station_Model_OCR.pdf

• Separation of recyclables and discards

• Nishtala, S. and E. Solano-Mora, 1997, “Description of the Materials Recovery Facilities Process Model: Design, Cost and Life-Cycle Inventory,” Project Report, North Carolina State University, Raleigh, NC. (https://webdstmsw.rti.org/docs/MRF_Model_OCR.pdf )

• Treatment including refuse derived fuel, waste-to-energy, yard- and mixed-waste composting

• Nishtala, S., 1997, “Description of the Refuse Derived Fuel Process Model: Design, Cost and Life-Cycle Inventory,” Project Report, Research Triangle Institute, RTP, NC.

• Composting process model: https://webdstmsw.rti.org/docs/Compost_Model_OCR.pdf

• Harrison, K. W.; Dumas, R. D.; Barlaz, M. A.; Nishtala, S. R., A life-cycle inventory model of municipal solid waste combustion. J. Air Waste Manage. Assoc. 2000, 50, 993-1003.

• Disposal including traditional and wet landfills and ash landfill

• Camobreco, V.; Ham, R; Barlaz, M; Repa, E.; Felker, M.; Rousseau, C. and Rathle, J. Life-cycle inventory of a modern municipal solid waste landfill. Waste Manage. Res. 1999. 394-408.

• Eleazer, W. E.; Odle, W. S.; Wang, Y. S.; Barlaz, M. A., Biodegradability of municipal solid waste components in laboratory-scale landfills. Environ. Sci. Technol. 1997, 31(3), 911-917.

• Sich, B.A. and M. A. Barlaz, 2000, “Calculation of the Cost and Life Cycle Inventory for Waste Disposal in Traditional, Bioreactor and Ash Landfills,” Project Report, North Carolina State University, Raleigh, NC. (https://webdstmsw.rti.org/docs/Landfill_Model_OCR.pdf )

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Available documentation (Cont.)

• Background process models to account for energy/electricity consumption and offsets, and

remanufacturing of recyclables

• Dumas, R. D., 1997, “Energy Consumption and Emissions Related to Electricity and Remanufacturing Processes in a Life-Cycle Inventory of Solid Waste Management,” thesis submitted in partial fulfillment of the M.S. degree, Dept. of Civil Engineering, NC State University.

• Energy process model: https://webdstmsw.rti.org/docs/Energy_Model_OCR.pdf

• Remanufacturing process model: https://webdstmsw.rti.org/docs/Remfg_OCR.pdf

• Decision Support Tool, Optimization and Alternative Strategy Generation

• Harrison, K.W.; Dumas, R.D.; Solano, E.; Barlaz, M.A.; Brill, E.D.; Ranjithan, S.R. A Decision Support System for Development of Alternative Solid Waste Management Strategies with Life-Cycle Considerations. ASCE J. of Comput. Civ. Eng. 2001, 15, 44-58.

• Solano, E.; Ranjithan, S.; Barlaz, M. A.; Brill, E. D. Life Cycle-Based Solid Waste Management 1. Model Development. J. Environ. Engr. 2002, 128, 981-992.

• Solano, E.; Dumas, R. D.; Harrison, K. W.; Ranjithan, S.; Barlaz, M. A.; Brill, E. D. Life Cycle-Based Solid Waste Management 2. Illustrative Applications. J. Environ. Engr. 2002, 128, 993-1005.

• Kaplan, P.O., 2006, “A New Multiple Criteria Decision Making Methodology for Environmental Decision Support,” Doctoral Dissertation, Dept. of Civil Engineering, North Carolina State University.

• Manual: https://webdstmsw.rti.org/docs/DST_Manual_OCR.pdf

• Tool Website: https://webdstmsw.rti.org/resources.htm

• Uncertainty Propagation and Sensitivity Analysis Tools

• Kaplan, P. O., 2001, “Consideration of cost and environmental emissions of solid waste management under conditions of uncertainty,” MS Thesis, Dept. of Civil Engineering, North Carolina State University.

• Kaplan, P. O.; Barlaz, M. A.; Ranjithan, S. R. Life-Cycle-Based Solid Waste Management under Uncertainty. J. Ind. Ecol. 2004, 8, 155-172.

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Scope I, II and III emissionsThe GHG Protocol and IPCC categorizes these direct and indirect emissions into three broad scopes:

Scope 1: All direct GHG emissions.

Scope 2: Indirect GHG emissions from consumption of purchased electricity, heat or steam.

Scope 3: Other indirect emissions:- the extraction and production of

purchased materials and fuels, - transport-related activities in vehicles

not owned or controlled by the reporting entity,

- electricity-related activities (e.g. T&D losses) not covered in Scope 2,

- outsourced activities, waste disposal,http://www.ghgprotocol.org/

Two different approaches to LCA

• Attributional approach (“accounting” or “descriptive approach”)

• Provide information on what portion of global burdens can be associated with a product and its life cycle

• Include processes that are actually directly linked by flows to the unit process that supplies the functional unit or reference flow

• Consequential approach (“change oriented approach”)

• Provide information on the environmental burdens that occur, directly or indirectly, as a consequence of a decision (usually represented by changes in demand for a product)

• Include processes that are actually affected by the decision, that change their output due to a signal they receive from a cause-and-effect chain whose origin is a particular decision

Illustrative GHG accounting