LCA OF BAGS IN MATER-BI®
The environmental impact caused by the manufacture and disposal of bags in Mater-Bi® used by families for the collection of organic waste was assessed using life cycle analysis, taking paper and polyethylene bags as references. The assessment covered all phases of the life cycle, from the raw materials to the manufacture, to the disposal of the product, including transportation.
PHASES OF THE PRODUCTION CHAIN AND CONTENTS OF THE SYSTEM
PRODUCTS SELECTED
The analysis took into consideration bags used and disposed of in Switzerland.
The reference products were selected on the basis of those currently on
sale in the large-scale retail trade, in Switzerland.
| Bags made of Mater-Bi® | Paper bags | Bags made of Polyethylene | |
| Material | Z-class Mater-Bi® | Kraft paper | HDPE |
| Country of origin | PCL:USAmaize: FranceMater-Bi®: Italy | Paper:
Sweden Bag: Switzerland |
Granules:Malaysia Bag: Malaysia |
| Disposal | Composting | Composting | Incineration |
| Dimensions (mm) | (220+220)x440 | (240+105)x510 | (180+360)x600 |
| Weight (g) | 9.15 | 59.6 | 7.04 |
CALCULATION
MODELS
The analysis was made according to the "impact oriented" model (Heijings,
1992; BUWAL 1996), using categories of the ECO-Indicator model (Goedkoop,
1995). The calculations were made using Version 2.2 of the EMIS (Environmental
Management and Information System) program. See the bottom of the page
for a more detailed description of the categories considered. The analysis
was carried out by an independent Swiss company, and certified in accordance
with EN ISO 14040.
ENERGY CONTENT
Paper bags consume much more energy than the corresponding bags made of Mater-Bi® and of PE, because of the greater weight.
GREENHOUSE EFFECT
Bags made of Mater-Bi® make a significant contribution to reducing the greenhouse effect, because of their natural constituents.
OVERALL
COMPARISON: MATER-BI®, PAPER AND POLYETHYLENE.
| Bag made of Mater-Bi® compared with: | |||
| Environmental impact category | bag made of PE | paper bag | bag made of PE, including incineration of the organic residue |
| Energy |
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| Greenhouse effect |
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| Acidification |
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| Nutrification |
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| Ozone formation |
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| Toxicity in air |
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| Toxicity in water |
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| Salification |
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| Waste produced |
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Legend:
(++) = much better
(+ ) = better
(0 ) = comparable
(- ) = worse
(--) = much worse
The life cycle analysis shows that bags made of Mater-Bi® clearly have a better environmental impact than paper bags, and are comparable with bags made of polyethylene incinerated alone after separation from the waste. However, experience of managing the composting process shows that complete separation of the plastic bag from the organic waste is not possible, as a significant quantity of non-separable organic material remains together with the plastic. This waste must be burnt together with the plastic. If we also consider this effect, the environmental impact of bags made of Mater-Bi® are clearly better than bags made of polyethylene.
Environmental impact categories considered in the analysis.
Energy: consumption
of energy resources (oil, natural gas, etc.), assessed from the energy
content of the resources necessary (MJ)
Greenhouse effect: temperature increase of the
planet due to gas emissions (CO2 equivalents)
Acidification: potential damage
to plants due to the emission of substances such as nitrogen and sulphur
oxides (SO2-equivalents)
Nutrification: potential unbalancing
of the water and of the soil due to the emission of substances that have
a fertilising effect, such as nitrates and ammonia (PO4-equivalents)
Ozone formation: increase in the formation of
ozone (summer smog) due to the emission of substances such as organic
solvents and nitrogen oxides (C2H4 equivalents)
Toxicity in air: pollution of the atmosphere
due to gas emissions
Toxicity in water: pollution of water due to
organic emissions, heavy metals, etc.
Salification: damage to flora and fauna in water
due to the emission of salts, such as chlorides (assessed as H+ ions)
Waste produced: quantity of waste disposed of,
weighed as inert substances, harmful toxic waste, radioactive waste, etc.