lundi 6 décembre 2010

Assess bioplymer's impact before launching its use

I share with this very interesting and relevant analysis of Katherine O'Dea, Senior Fellow for the Sustainable Packaging Coalition, published in the last issue of Packaging Digest

Material renewability not only factor in packaging sustainability

Biopolymers are often considered to be a more sustainable material choice for certain packaging applications. However, as their use increases, so does the need to understand how biopolymers really measure up from a sustainability perspective.

Sustainability metrics play a critical role in this assessment. How does a company select a meaningful set of metrics for biopolymer packaging? What might be a relevant set of metrics for comparison?

First, the use of a biopolymer does not by itself make a packaging format sustainable. Sustainability is complex and can't be measured by a single attribute such as material renewability. The material's life cycle must be considered in the context of the packaging's life cycle.

Since the biopolymers currently used in packaging are commonly derived from agricultural products-predominantly corn and sugar cane-the primary impacts could include fertilizers and pesticides use, water and energy use. In addition, the crops, particularly corn, may be genetically modified.

There are no sourcing standards or certifications to drive best practices in biopolymer feedstock sourcing, although the Better Sugar Cane Initiative is working on one. In addition, the food vs industrial use debate raises land use and social benefit issues.

On the other hand, the production process for some biopolymers may emit less problematic emissions than many petroleum-based polymers. Impacts of this life-cycle phase could include energy use and associated emissions. Some organic pollutants may contribute to acidification, and suspended solids may be released during material production. And, since pure biopolymers have limitations, chemicals may be added to meet performance or aesthetic requirements.

There are relatively few end-of-life options for biopolymers. Industrial composting could be an option, but few facilities exist and some do not accept biopolymer packaging due to the facility's required decomposition rate or a lack of knowledge about the materials. The other major issue is an inadequate collection and sorting infrastructure. PLA can contaminate PET recycling systems. Optical sorting exists to separate PLA from PET, but a majority of material recovery facilities cannot afford the equipment.

These life cycle factors raise a number of questions that suggest a set of metrics. What material inputs are required to produce the biopolymer? Where did the feedstock come from? Was any of the feedstock sourced in an underdeveloped country where child labor or forced labor used? How much energy is required to grow the feedstock and process it into a polymer? How much water is consumed in the agricultural phase? What types of releases to soil, water and/or air occur during growth, harvesting, processing and conversion? Will the percentage of biopolymer used make the package compostable? Will the biopolymer contaminate existing recycling streams?

In a scenario with these relevant business questions, the metrics might include: Total material use; percent renewable material use; material chain of custody; volume of water used from stressed sources; potential of acidification, eutrophication or fresh water eco-toxicity potential; use of child labor and/or forced labor; energy demand; global warming potential; composting rate; recycling rate; and landfill rate.

While the above constitute a meaningful set of sustainability metrics for biopolymers, they are based on the above hypothetical set of business questions. Business partners may pose different questions depending on specific sustainability goals and/or operating and market contexts.

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