Breaking Down: Can Compostable Packaging Set Us on the Path to Eco-Heaven? What does 'degradable' Really Mean?

Resource Magazine

Media Contact: Tony Breton

The retail sector is going green, or so we are told. The current swathe of energy efficient stores, locally sourced produce, Fair trade suppliers and improved recycling schemes proffered by major retailers are all very laudable, but the main bug-bear of the eco-conscious public remains the spectre of excess packaging. Luckily, moves are afoot to tackle this problem, and now that Ikea has introduced compostable carrier bags, Marks and Spencer is switching to compostable sandwich wrappers, and Co-op and Tesco are boasting degradable carrier bags, some might ask whether we are on the brink of a guilt-free, packaging utopia.

According to Wasteonline, over four million tonnes of plastics are used every year in UK packaging applications. These perform excellently and provide a lightweight, low cost solution for a raft of products. However, the qualities that make them appealing – low weight, high volume and the choice of a wide range of materials – means they can be difficult and expensive to collect and recycle. Whilst the plastics recycling industry is gradually establishing itself in the UK, particularly in the markets for PET (Polyethylene Terephthalate), the lack of renewability of these fossil fuel-based products is still a major issue. Consequently, a huge amount of research has been poured into finding alternatives based on naturally renewable and sustainable resources.

Such bioplastics do now exist and are increasingly popular, but in order to understand the role different types of bioplastics can play it is essential to define exactly what they are. Biodegradable plastics, for example, biodegrade through the action of naturally occurring micro-organisms, while compostable plastics can be safely composted together with the organic fraction of municipal solid waste. Compostable plastics do not hamper the composting process because they are biodegradable, disintegrable, safe and do not pollute the final compost. Compliance with the European Norm EN 13432 indicates that all these requirements are satisfied.

The majority of bioplastics are derived at least in part from renewable resources – starch and sugar – both of which come from annually renewable crops (starch coming from corn, wheat and potatoes) and are completely biodegradable.

“The public confuses biodegradability with degradability”

Degradable plastics on the other hand, are not bioplastics but are plastics based on polyethylene and contain a metal additive to promote degradation. Degradation typically takes between 18 months and four years and follows repeated fragmentation after exposure to UV light. No degradable plastic has yet been able to meet all the criteria of EN13432.

One of the first companies to produce a commercially viable compostable bioplastic was NatureWorks LLC. NatureWorks’ technology breaks down corn starches into natural plant sugars. The carbon and other elements in these are then used to make plastic, called polylactide (PLA), through a simple process of fermentation, separation and polymerisation. NatureWorks™ PLA is starting to replace traditional plastics in selected short-life, single use, rigid food packaging applications across the USA. Sam’s Club, a division of Wal-Mart Inc, will soon be supplying some of its fresh produce, such as fresh herbs and soft fruit, in NatureWorks™ PLA.

Whilst the material is becoming increasingly successful in the USA, it is not making similar inroads in the UK. One reason could be that a significant proportion of the corn grown in the USA is from genetically modified sources. To overcome this barrier, NatureWorks has recently introduced a GM-free range.

Another company to produce compostable rigid bioplastics from corn starch is the Australian-based Plantic Technologies. Known as Plantic®, this bioplastic is well suited to dry food products such as biscuits and confectionary and is currently being used in Nestlé’s Dairy Box across Europe and in Cadbury’s Milk Tray across Australia.

Europe’s largest manufacturer of compostable, starch-based bioplastics is Novamont, which operates a 35,000-tonne per year plant in Italy. Its product, Mater-Bi®, is a bioplastic consisting of starch complexed with fully biodegradable synthetic polymers (the company is currently working on a new range using vegetable based oils). Best known in the UK for its use in compostable sacks for local authority kitchen and garden waste collections, Mater-Bi® is used much more widely across Europe, where it crops up in everything from carrier bags and nappy liners, to plant pots, cutlery, fast food containers and knitted nets for fresh produce. UK retailers including Sainsbury’s, Tesco and the Co-op have all used Mater-Bi® in fresh produce packaging applications.

Not all compostable packaging is starch based. Innovia Films has developed its NatureFlex™ range of biodegradable films from sustainable wood pulp. The glossy films are essentially transparent papers and are compostable and natural-gas permeable. NatureFlex™ films are suitable for twist-wrapping (e.g. confectionary wraps), adhesive applications (sticky tape) and general packaging uses such as fresh produce bags.

While there are many examples of compostable packaging being used by retailers in the UK, probably the best-known is the degradable plastic technology used by Tesco and Co-op in its carrier bags. As already mentioned, this technology utilises traditional, non-renewable plastics with the addition of a degradation-inducing, metal-based additive. Although no degradable product has gained certification to prove biodegradability or compostability, these retailers see it as an economically viable stepping-stone towards more sustainable packaging, as the products degrade within four years as opposed to the estimated 1,000 years taken by traditional plastic bags. However, although this type of packaging does degrade more quickly than traditional plastics, it does not biodegrade within a standard UK composting system and so is best disposed of through recycling or energy from waste.

Since the development of the EU Packaging Regulations (which have been adopted in the UK), the European standard for compostable and biodegradable packaging – EN 13432 – was adopted. These standards ensure that a product is biodegradable, compostable, and safe. In order to gain certification to BS EN13432 (the British version of the EU standard) the final product must be fully tested and approved. If, and only if, it is certified under BS EN13432, is it acceptable for recovery through biological treatment under the UK Packaging Recovery Note scheme.

There are a number of certification bodies across the EU, but in the UK the main one is the Composting Association, which operates a certification scheme in partnership with the German certification body Din Certco. Packaging which is certified to BS EN 13432 is also an acceptable feedstock to commercial composting systems, which comply with BSI PAS100 for composted products. Once a product has been certified as compostable it can claim to be compostable and display the relevant logo. However, it is worth remembering that testing is undertaken in conditions similar to those in a commercial composting system and not a home composter.

The UK Animal By-Products Regulations (2003) state that the majority of compostable packaging be treated as catering waste (as it has come into contact with food), and therefore requires enclosed biological treatment (in-vessel composting, anaerobic digestion or mechanical biological treatment). With the introduction of the Landfill Allowance Trading Scheme, which sets targets and allows local authorities to ‘trade’ allowances, councils across the UK are beginning to take the separate collection of household food waste seriously. Given that this is the preferred collection mechanism for the majority of compostable packaging, it is essential that the UK compostable logo becomes as widely recognised as the established recycling symbols. Using words like compostable or biodegradable is not sufficient, as the public often confuses biodegradability with degradability. A recent court case in Italy (PI4927 no. 15104) deemed the use of the word degradable in packaging labelling as deceptive and that it should not be used to promote environmental compatability.

Compostable packaging offers enormous potential and will become progressively more widespread as the demand for sustainable solutions increases. With heightened demand comes lower prices and these will only be exaggerated as the price of mineral oil continues to grow. Whilst this might not happen overnight, it is likely that over coming years volumes will increase dramatically, at the same time as UK local authorities are investing in collection and treatment solutions for biodegradable resources. Maintaining and improving quality is key to the entire biological resource industry, if the current momentum can be maintained then we might just be looking at utopia after all.

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