1. 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 1

2. Use life-cycle-assessment modelling (LCA)
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 impacts C-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 impacts C-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

6. Quantification of impacts C-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

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

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

9. Characterization Factors
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: 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)

10. Characterization Factors
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: 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)

11. Mass balance of landfill: 100 years
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,

12. 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

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

14. Mass balance of plastic sorting and recyling
19% plastic in the MSW
Plastic and others in MSW
kg associated with 1000 kg MSW plastic waste
Source separation efficiency
MRF transfer-coefficients
PET
HDPE
POF mix
Plasmix
Iron
Aluminium
Bottles, plastic
270
80%
216 kg
70%
151 kg
20%
43 kg -
10%
22 kg
Soft plastic
360
50%
180 kg
144 kg
36 kg
Hard plastic
110
55 kg
51%
28 kg
31%
17 kg
18%
10 kg
Non-re-plastic
260
130 kg
100%
Total plastic (kg)
1000
581
151 71
161
198
Paper
2400
1.5%
35 kg
Wood
300
3.3%
Textile
Iron, cans
225
14%
32 kg
53%
47%
15 kg 75
13%
7 kg
30%
3 kg
Inert (Glass)
900 8%
70 kg
Total (kg)
5200
748
347 15 3
Plastic recycling
Down-cycling
Reject/ fuel
Metal recycling

15. LCA- modelling is the systematic approach Example of output in terms of CO2-equi. /ton MSW
Incineration
Plastic recycling
RDF in cement kiln
Metal recycling
Glass recycling
Paper recycling
Collection and transport
Anaerobic digestion
Plastic in cement kiln

16. Food waste and other bioresidues for 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

17. 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

18. A shortcut for determining uncertainty
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!

19. 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.

20. Thank you fro your attention
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