Biodegradable Packaging

Biodegradable packaging is increasingly being used by companies to package their products.  For example, some shops will have ‘biodegradable’ bags which aren’t as degradable as you might think.  Biodegradable packaging generally covers plastics and some paper based materials.  It can be used for:

• Compostable waste bags
• Carrier bags
• Biodegradable mulch film (which can be ploughed back into the field)
• Catering products
• Film packaging (for short shelf life products)
• Rigid packaging (for bottles and containers)

Types of Biodegradable Packaging

There are three main types of biodegradable packaging described below.

Degradable

Degradable packaging has metal additives added to break down the plastic over a period of time.  Degradable packaging is also known as ‘oxo-degradable’.

Biodegradable

Biodegradable packaging usually consists of a biological component such as starch, cellulose and other plant fibres.  This means it can be broken down biologically by microbes.

Compostable

Composting is a managed process that involves the biological decomposition and transformation of biodegradable material to produce carbon dioxide, water, minerals and organic matter (compost or humus) [1].  Compostable differs from biodegradable as the end product is compost.  Products made from compostable plastic are tested and are able to bio-degrade within six months.  However not all materials can be composted at home, some require high temperatures to break down, that are only possible in commercial composting systems [2].

A European Standard for Compostable and Biodegradable Packaging: EN13432

This is a European standard for packaging that is recoverable through composting and biodegradation.  It is a legally binding standard in all EU member states.  This means that in order to claim packaging is compostable, the standard has to be met and proof of compliance has to be demonstrated through a certification company.   The certification company will make sure that the following items are checked for consistency with the EN13432 standard:

• Disintegration
• Biodegradability
• Absence of any negative effect on the composting process
• Low levels of heavy metals (Potentially Toxic Elements) and no adverse effect of the quality of compost produced.

Other points to consider with biodegradable packaging

• A study by Loughborough University highlighted the uncertainty about the impact of the plastics on the natural environment when they begin to break down into smaller pieces [3].  Degradable plastic is hydrophobic (has little or no affinity for water) and may attract other hydrophobic particles – including pesticides and heavy metals – which can lead to bioaccumulation of toxic substances [4].
• Genetic Modification (GM) is a controversial environmental subject and it must be noted that there is some biodegradable packaging from the United States which is derived from GM crops.
• Intensive farming practices (large scale crops reliant on pesticides and fertilisers derived from fossil fuels) are generally used to produce the biological ingredients in bioplastics.
• Most biodegradable packaging currently ends up in landfill.  Unfortunately when biodegradable packaging breaks down in landfill, it is usually under anaerobic conditions (without oxygen).  This produces the harmful greenhouse gas methane.
• A large proportion of certified compostable plastic products available on the market today contain a high proportion of renewable raw materials [5].  Using renewable raw materials to make plastic is better than using fossil fuels.
• The biodegradation of compostable plastics is dependent on three main factors: elevated temperature, humidity and the abundance of microbes [5].   Therefore quick biodegradation will only happen in the presence of all these criteria at the same time.  Thus commercial composting is the only likely way that some compostable products will be broken down into a compost product.
• Currently no UK local authority will accept bioplastic packaging in the organic waste collection, except kitchen caddy liners, due to the risk of contamination with conventional plastics [6].
• Oxo-degradable plastics are not suitable for recycling with main-stream plastics [1]. The recyclate will contain additives that will make the recycled plastic more susceptible to degradation.

References

[1] Loughborough University (2010) Assessing the Environmental Impacts of Oxodegradable Plastics Across Their Life Cycle  http://www.european-bioplastics.org/media/files/docs/en-reviews/EV0422_8858_FRP.pdf

[2]  Soil Association (2006) Reduce, Reuse, Recycle: A Guide to Minimising the Environmental Impact of Packaging.  http://www.soilassociation.org/LinkClick.aspx?fileticket=jusGScfbhRU%3d&tabid=353

[3]  The Environmentalist. Issue 95, April 2010. IEMA

[4] Association for Organics Recycling (2010) http://www.organics-recycling.org.uk/index.php?option=com_content&view=article&id=107:introduction&catid=40:packaging-a-certification&Itemid=76

[5]  European Bioplastics (2008) Bioplastics FAQs http://www.european-bioplastics.org/index.php?id=191

[6] WRAP (2009) Biopolymer Briefing http://www.wrap.org.uk/downloads/Biopolymer_briefing_26_jan_09_final1.1d07f394.4907.pdf