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  • Ophelie Gourdou

Compostable/ biodegradable plastic packaging —> real benefit or greenwashing?


I am struggling since I dig into the sustainable packaging solutions, with the claim “biodegradable” and “compostable” of some plastic packagings. At first sight, and for the majority of the consumers, this sounds like a real benefit for the environment. Consumers are aware of the plastic pollution in the ocean and are happy if they stop contributing to it. But let’s have a deeper look at this promise: 

Biodegradable means that the packaging will degrade over time under the action of microorganisms in the environment where it lands. There are many different environmental conditions like compost, soil, fresh or marine water where the process of degradation can take few months or several years. 

 Compostable is more specific and means that the packaging item will degrade if thrown away in an industrial or home compost. 

The European Standards EN 13432 “Requirements for packaging recoverable through composting and biodegradation” defines the conditions to fulfil in order to claim “compostable packaging”- it is designed for industrial composting only. There is no international standards for home composting , however there are several national ones like in Australia (AS 5810) or in Belgium (OK compost HOME).

Biodegradable is not defined by international norms and this claim is actually often used to mean compostable according to the EN 13432 Norm. Specific certifications are however available like OK biodegradable SOIL / WATER / MARINE from TUV Austria and Vinçotte. 

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How should you handle a biodegradable (=compostable) plastic packaging at the end of its life? 

If you are in a country with organic waste collection, you might be tempted to throw it away in this bin, as this is going to an industrial compost facility but…you might be wrong! In Germany for example, it is forbidden to dispose bioplastic in the Biomüll (organic waste bin). The reason is that the conditions defined by the Norm are not completely met in reality (i.e. shorter residential time) and the plastic is not completely degraded at the end of the process. There has been a continuous communication campaign in Munich from the waste management company to say NO to plastic into the Biomüll, even biodegradable waste bags sold for this purpose. 

You might choose to put this packaging to the plastic recycling bin, but most of the time it will not be ecycled, as this is not a “conventional” resin. So it will end up in the incineration for energy recovery. Same end of life with you throw it away in the residual waste bin. In this case, being compostable is not a benefit at all!

In some other countries like UK or France, landfill is still in practice and a big part of the plastic waste ends up there : 38% in average for Europe! Some may think it will degrade under this conditions, but what exactly happens to compostable plastic in landfills is up to debate. Some studies shows that it will break down to release methane, a powerful greenhouse gas, but another study found that it doesn’t degrade. Home composting (which is by the way not accessible to everyone) will give the same level of uncertainty regarding degradation of compostable plastic, as the conditions are different than defined by the norms. 

So which end of life option is left ? The worst case scenario: plastic waste littered in the nature, rivers, or ocean. As mentioned above, compostable plastic waste were not tested to biodegrade under those conditions and will degrade badly if not at all in the environement. 

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After doing this analysis, it seems to me that biodegradable / compostable plastic claims are somehow misleading. Where is the benefit as this plastic waste will end up most of the case in conditions where there is no guarantee of degradation?

Shouldn’t we go one step further to close the loop? 

Spread installation of industrial composting facilities, combined with adapted waste recycling AND set appropriate conditions to allow compostable plastic wastePerform the degradation test taking into account real life scenarios: landfill, fresh or marine water with a proper certification 

Another thought: those compostable plastic are very often bioplastic, made from renewable agricultural sources, with lower carbon footprint than conventional plastic. Why don’t we highlight those real benefits instead?

Food for thoughts, looking forward your comments!


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