Debate: Bioplastics - a threat to recycling
10 Jan 2012
How environmentally friendly are bioplastics really? Their total environmental impact can be great, and traditional recycling is threatened, write Christer Forsgren, Stena Metall and Chalmers University of Technology, and Tord Svedberg, IVL Swedish Environmental Research Institute.
In just a few years bioplastics have achieved widespread use in Sweden, not least in products that are marketed as environmentally friendly. This label has a downside, however, since the use of biodegradable plastics complicates the recycling of more traditional plastics. It is high time for the government to investigate this issue and draft guidelines on the use of bioplastics.
The expression bioplastics is used to describe two different terms at the same time, which often leads to confusion. It can mean that the plastic is biodegradable or that the raw material in the plastic is renewable or biobased. Europe currently accounts for half of the market.
Last year bioplastic production passed 1 million tons, with an estimated growth rate of nearly 20 percent per year. According to a recently published report by Ceresana Research, the share of non-biodegradable bioplastics is expected to increase to nearly 50 per cent within a seven-year period.
All bioplastics aren’t as environmentally friendly as its name implies. Even though the raw material is biobased, you can’t be sure that the total environmental impact is low. A great deal of energy is consumed to produce, transport and convert both ordinary plastics and bioplastics. For example, the manufacture of polylactic acids (PLA), one of the most common bioplastics, requires a process involving many different chemicals.
Bioplastics often have to be stabilized as well in order to withstand heat and humidity and to be used in many applications. The stabilization process means, however, that the material won’t break down for a relatively long period of time. In nature it could take several years. Tobreak it down quickly and completely requires special equipment where temperature, humidity and microorganisms are controlled.
Bioplastics also represent a threat to the viable recycling of conventional plastics. Plastic recycling requires separating different types of plastics by machine. No matter how good the equipment is, there will always be a small percentage of material that is incorrectly sorted.
The addition of biodegradable plastics into recycled, non-biodegradable plastics can have devastating consequences for the lifecycle of the recycled plastic. In addition to the quality aspect, it will mean an increase in the need for new plastic raw material in the long term.
To avoid sabotaging the future of plastics recycling and increasing our dependency on new raw material, we need a two-part strategy where as much conventional plastic as possible is recycled at the same time that the introduction and use of bioplastics is regulated. They should only be used in applications where the benefits are obvious and where the risk that they will be mixed with plastics that can be recycled is as small as possible.
It is high time that the government appoint a committee to investigate the use of bioplastics and their environmental impact from a lifecycle perspective. Pending the results of such an investigation, it is important that consumers are made aware that bioplastics aren’t automatically environmentally friendly.
Christer Forsgren, Head of Technology and Environmental Science at Stena Metall and Assistant Professor at Chalmers University of Technology
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