ecological and economical optima of material recycling · doka life cycle assessments, zurich 4...
TRANSCRIPT
Ecological and economicaloptima of material
recycling
Presentation at the 3rd International Conferenceon Life Cycle Management Zurich, August 27–29, 2007
Doka Life Cycle Assessments, Zurich
lcm07 {at} doka.ch
Buero fuer Analyse und Oekologie BAO, Zurich
patrick_hofstetter {at} yahoo.com
By Gabor Doka & Patrick Hofstetter
Project funded by BAFU Bundesamt Fuer Umwelt (Swiss EPA)
2Doka Life Cycle Assessments, Zurich Buero fuer Analyse & Oekologie, Zürich
Contents
1. Approach to assess recycling systems in LCI
2. LCIA methods, Monetarisation & Hidden Costs
3. Case Study: Galvanising Sludge Recycling
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GoalCompare recycling systems with established waste disposal
Is recycling beneficial?
When is recycling beneficial?
Which coherent approach can assess various recycling schemes for different waste materials?
Project funded by BAFU (Swiss EPA, Bundesamt fuer Umwelt) “Erweiterung der Ökobilanzmethodik für verbesserte Modellierung einer Kreislaufwirtschaft“
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Approach System BoundariesRecycling processes generally have two functions:(1) to dispose of waste and (2) to produce secondary materials Multi-functional process (disposal and supply)
Often in LCA we are only interested in one of these functions:E.g. Cement kilns fired with waste oil or other secondary fuels. Which burdens are attributable to the cement product?E.g. Plastic beverage packaging recycled as fleece textiles. Which burdens are attributable to the beverage packing disposal?
Usually solved with Allocation (÷) or Substitution (–) .
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DisposalFunction1 kg
SupplyFunctionx kg
Approach System BoundariesBUT: To compare recycling processes with other options it is not necessary to isolate the disposal and supply functions of recycling. Make sure that both options fulfil the same range of functions:
Recycling process
Waste
Recyclate
Landfill
Waste
Option Recycling Option Unrecycling
Primary production
Product
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DisposalFunction1 kg
SupplyFunctionx kg
Approach System BoundariesBUT: To compare recycling processes with other options it is not necessary to isolate the disposal and supply functions of recycling. Make sure that both options fulfil the same range of functions:
Collection of functions, that both options must provide:
Utility BasketThis is System Expansion+
+ISO unfortunately calls Substitution (–) also System Expansion
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Life Cycle Impact AssessmentWe used existing LCIA methods:• Eco-indicator’99• Swiss ecoscarcity method 97 (BUWAL-method, UBP’97)• Update Swiss ecoscarcity 06 (Draft Version, UBP’06)
New, simple Monetarisation Approach (Patrick Hofstetter)• By direct proportionality to LCIA scores.• Based on ‘willingness to accept’-approach
(estimated compensation to accept an inflicted damage)• In Swiss Francs 2005 (CHF)
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Simple Monetarisation
Damage cost data
Based on... References
...CO2
Krewitt; Downing;
Watkiss; Stern Rabl; Krewitt;
SpadaroHofstetter &
Müller-Wenk; Rabl; ARE
Ott
...PM10
... DALYs
... Ext. Cost StudySwitzerland
Unit Low Medium Large
CHF/kg
CHF/kg
CHF/DALY
CHF/yr 1.0E10 1.6E10 2.16E10
0.450.110.024
19 100
260’00090’000
Various external cost studies:
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Simple Monetarisation
Total LCIA burden [points]
Total external environmental LC-costs [CHF]· K [CHF/point] =
Obtain Monetarisation by direct proportionality to LCIA scores:
CHF2005 per Eco-indicator‘99(HA)-point
Based on... Low K Medium K Large K
...CO2 4.4 20.2 82.6
...PM10 2.0 10.3
...DALYs 3.5 10.0
....Ext. Cost Study CH1.8
(rev. 5.6)2.9
(rev. 8.6)3.9
(rev. 11.6)
This study 3.5 10 40
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Simple Monetarisation
And for the ecoscarcity methods per 1000 UBP-points
CHF per 1000 UBP‘97-points CHF per 1000 UBP‘06-points
Low
0.12
0.17
0.15
0.15
Medium Large
0.55
0.91
0.24
0.55
2.25
0.32
1
Based on... Low Medium Large
...CO2 0.08 0.35 1.45
...PM10 0.13 0.67
... Ext. CostStudy CH 0.07 0.11 0.15
This study 0.1 0.35 0.7
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Other Hidden CostsEnvironmental damage costs are not the only external costs, e.g.:• Resource production subsidises• Military expenses for resource production security• Lower environmental standards in developing countries• Closure and renaturation of mines• Missing worker’s health and accident risks compensation• Effects of deteriorating resource grades
Work in progress
Preliminary conclusion: With the exception of oil, environmental damage costs dominate the total external costs caused by resource extraction and production.
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Environmental damage costs
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Case Study: Galvanising sludgeGalvanising sludge from electroplating operations
SludgeE.g. copper plating
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Case Study: Galvanising sludge
Disposal options for galvanising sludge
Salt mine storage
Landfill
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Case Study: Galvanising sludge...or recycling in metal smelters
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Process galvanising sludge recycling
Galvanising Sludge
Secondary Zinc
Slags
Electrolysis Pb-Smelter
Secondary Lead
Lead-rich dust
Disposal Function1kg sludge
SupplyFunctions10 g Pb130 g Zn
Drying, transport
Zn-Smelter
Energy, materials Waste-specific emissions
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Sludge Recycling vs. Unrecycling
Landfill
Sludge
Option Recycling Option Unrecycling
10 g Pb130 g Zn
Recycling process
Sludge
RecyclatesPrimary Zn
130 g Zn
Primary Pb
10 g Pb
Flows not in proportional size
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Utility basket for sludge disposal
1 kg sludge disposal+ 130 g of zinc+ 10 g of lead
Based on the sludge composition and recycling processes additional functions and/or different amounts can result.
If any of the options cannot fulfil the whole basket, reference processes can be added as complement
= demerit or malus for lost opportunities
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Primary production• The primary production processes are essential in assessing the
suitability of recycling schemes.• LCI of metals is still patchy. LCI databases, like ecoinvent, have
but coarse LCI of metals.
• E.g. tailings: large volume, metal-bearing waste from metal ore beneficiation
• Problems with metal leaching, acidification of leachate (acid rock drainage ARD)
• Long-term legacy of mining sites.
E.g. 12 kg tailings per kg zinc, 350 kg tailings per kg copper
• Important for a complete LCA of primary metal production.
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TailingsGlobal annual production of tailings:Several hundred million tons (Jakubick & McKenna 2003)
Tailings and other mining waste production is larger than the amounts moved annually by natural erosion(Gardner & Sampat 1998)
Example tailings dump site
~1km
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Tailings disposalPreliminary model for emissions from tailings dump sites created for this study.
In analogy to landfill models used in ecoinvent database (Doka G. (2003) Life Cycle Inventories of Waste Treatment Services. ecoinvent 2000 report No. 13. EMPA St. Gallen, Swiss Centre for Life Cycle Inventories, Dübendorf, CH)
Burdens from tailings make up 0.5%–60% of the burden of primary zinc, copper, nickel, or lead, depending in the LCIA method.
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Results galvanising sludge diposalUtility basket = 1 kg disposal + 138g Zn + 9.4 g Pb + 3.4 g Ni + 3.5 g Cu + 560 g abrasive mineral
50‘000
0Recycling Unrecycling
Eco
scar
city
97 p
oint
s
Sludge in smelters
Sludge in landfill
Malus for zinc
Malus for other notdirectly fulfilledfunctions** mainly from lost copper
→ Lots of room forimprovement also for therecycling option
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Results galvanising sludge diposalIs there a threshold, where recycling is not sensible anymore?Results for galvanising sludge with variable zinc content (x-axis)
Typical result
Similar also for other LCIA-methods and other metals.
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Monetarisation Results
• Damage costs for Option Recycling are several thousand CHF per ton lower than for Option Unrecycling
• Where promotion of recycling is necessary, very large subsidises for recycling(or penalties for unrecycling) can be justified.
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Conclusions• Utility Basket: A simple, transparent approach to assess various
disposal options
• Environmental costs directly from single-score LCIA methods
• Environmental costs usually dominate hidden costs
• Environmental costs are very large compared to market prices
• Current LCI of primary metal production is still incomplete: major burdens yet to be added (esp. long-term effects of tailings and mine drainage)
• This affects primary production, and thus usually favours recycling
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Thank you for your attention
Disposal in Beijing