PE AmericasMarch 4th, 2009

Comparative Life Cycle Assessment of Oxo-degradable and Conventional Polyethylene Carrier Bags

Comparative Life Cycle Assessment of Oxo-degradable and Conventional Polyethylene Carrier Bags

1. Background

2. Introduction to LCA

3. Goal and Scope of LCA

4. Baseline of study

5. LCA results – Top level view

6. LCA results - Main conclusions

7. Impact of Revert additive production

8. Detailed results

9.Environmental categories explanation

319.04.2023 319.04.2023

Study commissioned by Oxobioplast

Additive information from Wells plastic (UK)

Study performed by PE Americas in collaboration with Five Winds

Study critically reviewed by:

• Paul Firth [The Green Standard]• Edgar Rojas [The California Integrated Waste Management Board]• Rita Schenck [The Institute for Environmental Research and Education]

Study carried out according to the guidelines established by the ISO 14040 standards

Background

4

Raw Materials

MaterialsManufacture

ProductManufacture

Transportation& Distribution

UseRecyclingEnd

Disposition

Introduction to LCASystems based approach

Goal and Scope of LCAOverview of Approach

“comparison of environmental burdens over the life cycle of PE carrier bags with Reverte additive and PE carrier bags without the

Reverte additive”

Baseline Overview of Approach

• Degree of mineralization of PE carrier bag with additive – 80%

• Aerobic conditions account for 5% of the decomposition process, with the remainder of decomposition taking place under anaerobic conditions. During the aerobic phase, the primary gas produced is CO2 alone.

• Under anaerobic conditions, the carbon content is converted into CO2 and CH4 in equal proportions.

• The net impacts of methane emissions are modeled as per the breakdown given above. The carrier bag system is given a credit equivalent to the amount of energy recovered, when methane emissions from landfills are captured for energy recovery.

• In the absence of data on littering rates in the US, a 1% rate was used as a reference for the evaluation. A sensitivity analysis with littering rates varying from 0.1% to 10% was also carried out.

LCA resultsTop level view

PE carrier bag without additive PE carrier bag with additive Difference

Life cycle Environmental impact (per 100 bags) (per 100 bags) (per 100 bags)

Total primary energy demand [MJ] 55.65 52.18 3.47Non-renewable [MJ] 55.01 51.68 3.33Renewable [MJ] 0.64 0.50 0.14

Acidification Air [mol H+ Equiv.] 0.41 0.34 0.08Eutrophication Water [kg N-Equiv.] 0.00 0.00 0.00Global Warming Air [kg CO2-Equiv.] 1.88 5.06 -3.18Smog Air [kg NOx-Equiv.] 0.00 0.00 0.00Waste generation [kg] 0.52 0.11 0.41

Post-industrial [kg] 0.01 0.01 0.00Post-consumer [kg] 0.52 0.10 0.41

Biological oxygen demand [kg] 0.00 0.00 0.00Chemical oxygen demand [kg] 0.00 0.00 0.00

Worse environmental impactBetter environmental impactEquivalent environmental impact

LCA resultsMain conclusions

•The additional environmental burdens associated with the production of the Reverte additive from cradle to gate (raw material extraction, production of components and final mixing) are not significant in the context of the life cycle of the PE bags.

•The main environmental impacts of polyethylene bags with the Reverte additive, when compared with polyethylene bags without the additive, occur at the end of life of the PE bags with Reverte, and are related to the by-products of microbiological digestion of the degraded polymers.

•PE bags with Reverte additive have a lower life cycle environmental profile when compared with the same bags without Reverte, in terms of primary energy demand, air acidification and post consumer waste generation. This is mainly due to microbiological digestion of the PE polymers (transforming the polymers into biomass, methane and carbon dioxide) and the recovery of methane for energy production in some US landfills.

•The additional emission of greenhouse gases (mostly Carbon dioxide) due to the microbiological digestion of the degraded polymers is reflected in a comparatively higher Global warming potential for PE bags with Reverte. This might be reduced in the future with increase of flaring and energy recovery systems in US landfills.

•The difference in life cycle environmental impacts for PE bags with Reverte and polyethylene bags without the additive is not significant in the areas of Eutrophication, smog creation, generation of industrial waste, biological oxygen demand and chemical oxygen demand. In those environmental impact categories the life cycle environmental impact of both types of bags is equivalent.

LCA resultsEnvironmental impact of revert additive production (cradle to gate)

Reverte additive Displaced PE Difference(6.24 grams per 100 bags) (6.24 grams per 100 bags) (per 100 bags)

Total primary energy demand [MJ] 0.82 0.51 0.30Non-renewable [MJ] 0.76 0.51 0.25Renewable [MJ] 5.85E-02 4.69E-03 0.05

TRACI, Acidification Air [mol H+ Equiv.] 5.17E-03 3.25E-03 1.91E-03TRACI, Eutrophication Water [kg N-Equiv.] 8.06E-06 5.28E-07 7.53E-06TRACI, Global Warming Air [kg CO2-Equiv.] 3.38E-02 1.56E-02 1.82E-02TRACI, Smog Air [kg NOx-Equiv.] 2.50E-09 1.13E-09 1.37E-09Waste generation [kg] 5.22E-05 4.55E-03 -4.49E-03

Post-industrial [kg] 5.22E-05 4.55E-03 -4.49E-03Post-consumer [kg] 0.00E+00 0.00E+00 0.00E+00

Water consumption [kg] 0.19 1.84E-02 1.68E-01Biological oxygen demand [kg] 4.42E-09 2.04E-08 -1.60E-08Chemical oxygen demand [kg] 4.09E-07 2.82E-07 1.27E-07

Better env. Profile

Worse env. Profile

LCA results Global Warming Potential by life cycle stage

LCA results Primary energy demand per life cycle stage

LCA results Life cycle air acidification potential

LCA results Life cycle Eutrophication potential

0.00E+00

1.00E-05

2.00E-05

3.00E-05

4.00E-05

5.00E-05

6.00E-05

Polyethyleneproduction

Carrier bagmanufacturing

Reverte additivemanufacturing

End-of-life

Eu

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(kg

N-E

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) PE carrier bag without additive

PE carrier bag with additive

LCA results Life Cycle Smog creation

LCA results Life cycle solid waste generation

Life cycle solid waste PE carrier bag without additive PE carrier bag with additive Difference( per 100 bags) (per 100 bags) (per 100 bags)

Post-industrial [kg] 0.008 0.008 0.000Post-consumer [kg] 0.516 0.103 -0.413Total life cycle solid waste generation 0.524 0.111 -0.413

LCA results Influence of littering rate on global warming potential results for PE carrier bag with additive

Effect: Increased warming of the troposphere due to anthropogenic greenhouse

gases e.g. from the burning of fossil fuels.

Reference Substance: Carbon Dioxide (CO2)

Reference Unit: kg CO2-Equivalent

Source: IPCC (Intergovernmental Panel on Climatic Change)

CO2 CH4

CFCs

UV - radiation

AbsorptionReflection

Infraredradiation

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Introduction to LCAGlobal Warming Potential (GWP)

Effect: Increase in the pH-value of precipitation due to the wash-out of acidifiying gases

e.g. Sulphur dioxide (SO2) and Nitrogen oxides (NOx).

Reference Substance: Sulphur dioxide (SO2)

Reference Unit: kg SO2-Equivalent

Source: CML, (Heijungs, Centrum voor Milieukunde Leiden), 1992

Introduction to LCA Acidification Potential (AP)

SO2

NOX

H2SO44HNO3

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Effect: Excessive nutient input into water and land from substances such as

phosphorus und nitrogen from agriculture, combustion processes and effluents.

Reference Substance: Phosphate (PO4-)

Reference Unit: kg PO4- Equivalent

Source: CML, (Heijungs, Centrum voor Milieukunde Leiden), 1992

Introduction to LCA Eutrophication Potential (EP)

Waste water

Air pollution

Fertilisation

PO4-3

NO3-

NH4+

NOXN2O

NH3

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HydrocarbonsNitrogen Oxides

Dry and warmclimate

Hydrocarbons

Nitrogen Oxides

Ozone

Effect: Formation of low level ozone by sunlight instigating the photochemical reaction

of nitrogen oxides with hyrocarbons and volatile organic compounds (VOC)

Reference Substance: Ethylene (C2H4)

Reference Unit: kg C2H4 -Equivalent

Source: Udo de Haes et al., 1999

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Introduction to LCA Photochemical Ozone Creation Potential (POCP) - Summer smog