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C-accounting and the role of LCA in waste management

C-accounting and the role of LCA in waste management. Thomas H Christensen Technical University of Denmark ICWMT Beijing, PR China October 2016. Introduction. Waste management can be described by three main challenges Controlling esthetic, hygienic and contamination risks

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C-accounting and the role of LCA in waste management

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  1. C-accounting and the role of LCA in waste management Thomas H Christensen Technical University of Denmark ICWMT Beijing, PR China October 2016

  2. Introduction • Waste management can be described by three main challenges • Controlling esthetic, hygienic and contamination risks • Recovering resources: materials, energy and elements/nutrients • Socio-economical acceptance • Our managing approaches have over time been named by a range of concepts and slogans • Waste hierarchy • Cradle-to-grave, cradle-to-cradle • Zero waste • Green technology • Sustainable technology • Circular economy • Today’s presentation: Environmental quantification • 3 take-home-messages: • Quantification of climate change impacts: C-accounting • System approach • Move from single value quantification to distributions Use life-cycle-assessment modelling (LCA)

  3. Quantification of impactsC-accounting/climate change • Environmental impacts are many: • Climate Change • Eutrophication (freshwater, marine, terrestrial) • Acidification • Human Toxicity (carcinogenic, non-carcinogenic) • Ecotoxicity • Particulate Matter (air) • Resource Depletion (fossil, abiotic)

  4. Quantification of impactsC-accounting/climate change • Environmental impacts are many: • Climate Change • Eutrophication (freshwater, marine, terrestrial) • Acidification • Human Toxicity (carcinogenic, non-carcinogenic) • Ecotoxicity • Particulate Matter (air) • Resource Depletion (fossil, abiotic) • In general: • For bulk waste: MSW, demolition waste, agricultural waste etc: Climate change is important • For specific/hazardous waste: WEEE, shredder waste etc: Toxicity is important

  5. Quantification of impactsC-accounting/climate change For waste management we cannot directly use the approach of IPCC • Environmental impacts are many: • Climate Change • Eutrophication (freshwater, marine, terrestrial) • Acidification • Human Toxicity (carcinogenic, non-carcinogenic) • Ecotoxicity • Particulate Matter (air) • Resource Depletion (fossil, abiotic) • In general: • For bulk waste: MSW, demolition waste, agricultural waste etc: Climate change is important • For specific/hazardous waste. WEEE, shredder waste etc: Toxicity is important

  6. The waste management system Load to the environment • Mass balances • Energy budget • Emission account emissions emissions emissions Materiales and energy can substitute for other production of materials and energy materiale waste materiale waste materiale waste energy Saving to the environment materiale energy

  7. The system approach has go beyond the waste management system emissions emissions emissions Materiales and energy can substitute for other production of materials and energy materiale waste materiale waste materiale waste energy materiale energy

  8. Characterization Factors C counting as GHG: Consider changes caused by waste management: Biogenic CO2 is neutral • C-fossil emitted as CO2: GWP = 1 Kg CO2-eqivalents/ kg CO2 • C-fossil bound: GWP = 0 • C-biogenic emitted as CO2: GWP = 0 • C-biogenic bound: - 3.67 Kg CO2-eqivalents/ kg C bound (after 100 years) • avoided C-fossil emitted as CO2: GWP = -1 Kg CO2-eqivalents/kg CO2 • avoided C-biogenic emitted as CO2: GWP = 0 • release of bound C-biogenic: 3.67 Kg CO2-eqivalents/ kg C released • C emitted as methane: 28 kg CO2-equivalents/ kg CH4 (100 years)

  9. Characterization Factors C counting as GHG: Consider changes caused by waste management: Biogenic CO2 is neutral • C-fossil emitted as CO2: GWP = 1 Kg CO2-eqivalents/ kg CO2 • C-fossil bound: GWP = 0 • C-biogenic emitted as CO2: GWP = 0 • C-biogenic bound: - 3.67 Kg CO2-eqivalents/ kg C bound • avoided C-fossil emitted as CO2: GWP = -1 Kg CO2-eqivalents/kg CO2 • avoided C-biogenic emitted as CO2: GWP = 0 • release of bound C-biogenic: 3.67 Kg CO2-eqivalents/ kg C released • C emitted as methane: 28 kg CO2-equivalents/ kg CH4 (100 years)

  10. Biogenic C Mass balance of landfill: 100 years Depends on the degradation k Manfredi,S. & Christensen,T.H. (2009): Environmental assessment of solid waste landfilling technologies by means of LCA-modeling. Waste Management, 29, 32-43.

  11. System approach • We need to include the upstream (energy and materials used) and the downstream (savings by recycling and use of recovered energy) activities in our quantitative model for GHG accounting • Usually a range of technologies are needed to achieve recovery of materials, energy and elements/nutrients • Waste is a heterogeneous material and most single technologies have rejects/residues that need other treatment • A simple system may look like

  12. Plastic recycling: mechanical treatment of source separated mixed plastic

  13. Mass balance of plastic sorting and recyling 19% plastic in the MSW Plastic recycling Down-cycling Reject/ fuel Metal recycling

  14. LCA- modellingisthesystematicapproachExample of output in terms of CO2-equi. /ton MSW Collection and transport Paper recycling Glass recycling Anaerobic digestion Metal recycling RDF in cement kiln Plastic in cement kiln Plastic recycling Incineration

  15. Food waste andotherbioresiduesfor green energy • Alternative uses • Land-use-change • Fodder production • Not single values but intervals/ average plus 95% confidence • Use of a consequential approach Tonini, D. et. 2016 Technical Univ. of Denmark

  16. Moving to distributed results • Variation in results can be of different nature • Modeling approach • Scenario setting • Parameter values • One approach: • Parameterize all values and choices in the model • Estimate the distribution of each parameter • Run Monte Carlo simulations

  17. A shortcut for determininguncertainty Simple calculation of sensitivity ratio The variation around the average result can be calculated analytically with Global Sensitivity Analysis For each model parameter: The total scenario uncertainty can be obtained summing the contribution to uncertainty of each parameter Same as input to Monte Carlo!

  18. Few parameters describe the uncertainty Identification of IMPORTANT parameters Uncertainty output= Σ (Uncertainty priority) + Σ (Uncertainty remaining) Bisinella, V., Conradsen, K., Christensen, T.H., Astrup, T.F. (2016). A global approach for sparse representation of uncertainty in Life Cycle Assessments of waste management systems. Int. J. Life Cycle Assess. 21, 378–394.

  19. Conclusion • Use LCA to understand your waste management system • It provides a stringent understanding of your system • It provides transparency as to what matters • Use a system approach • Include those parts outside the waste management system • The savings usually take place outside our system, but are still important • The context defines the system • No single value results in the future –hopefully • Accept that results are uncertain • Provide quantification of uncertainty • Simplified methods are available targeting your data collection • In C-accounting • Use consistent characterization factors also those you do not like Thank you fro your attention

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