Making degrade

We are all being encouraged to recycle more and more and to compost at home. But just when we think we’re getting the hang of which waste goes into which container, a whole new group of materials is invented for us to understand.

So what do you do if you collect your garden waste in a degradable plastic bag? Can you dispose of this at your nearest civic recycling site? And will the operator allow you to put your plastic bag in the compost, even if you inform them that it will break down? What is the difference between degradable and biodegradable packaging? As a consumer, which packaging should you choose to be sustainable?

As local authorities gear up to encourage more home composting, and organisations such as the Waste Resources Action Programme (Wrap) continue to drive the Big Recycle campaign, consumers are more aware of the need to act responsibly at home with waste. However, with 35-40% of all household waste derived from retail purchase, and 20% of this waste being packaging (4.5M tonnes a year in England), is it time for high-street retailers to produce common labelling for packaging, and help their customers do the right thing at home?

Biodegradable packaging

Some think that packaging nirvana can be summarised as growing your own packaging and then returning it to the soil after it has been used, and this technology is now possible. The ability to grow crops, harvest them and convert the starch into a form of plastic has been available for some time.

Higher oil prices are making them more affordable. Plants are a renewable resource, and produce starch from photosynthesis, cereal plants and tubers usually contain large amounts. Starch can be harvested from crops such as corn, wheat or potatoes and converted by various chemical processes into a number of polymers with a range of properties similar to oil-based plastics. Common polymers of this sort include polylactic acid (PLA) available for example from Natureworks in the US and Mater-Bi from Novamont in Italy.

Such polymers are plant-based, although in the UK some consumers may be concerned about the source of the crop, as all sources of PLA do use genetically modified varieties of wheat or corn, which might not be palatable, even in non-food formats.

Being derived from vegetable sources, these packaging products can biodegrade. Globally different standards are used to define biodegradability. In the UK, the BS EN 13432:2000 specifies requirements and procedures to determine the compostability and anaerobic treatability of packaging and packaging materials by addressing four characteristics:

• Biodegradability
• Disintegration during biological treatment
• Effect on the biological treatment process
• Effect on the quality of the resulting compost

In the UK, there are a range of organisations such as the National Non-Food Crops Centre and the Home Grown Cereals Authority which are actively researching suitable plant polymers for biodegradable packaging. These are supported by the government’s non-food crop strategy to help diversify the rural economy.

Degradable packaging

In contrast to biodegradable polymers, degradable polymers are oil-based, and not from an agricultural source. Terms such as degradable, oxy-degradable or UV-degradable are plastics that contain additives to break down under UV exposure or dry heat or mechanical stress, leaving small particles of polyethylene consumed by micro-organisms. The additives used in such plastics are usually metal-based compounds. In the open air, degradable packaging will break down over time. But there are concerns regarding landfill of such products in the absence of air and light.

Retail impact

As part of the move towards sustainable retailing, 13 high-street food retailers have agreed under the Courtauld Commitment to support the delivery of Wrap’s objectives to reduce household food and packaging waste.

An example of good practice can be seen from Sainsbury’s – a keen promoter of home-compostable packaging. Sainsbury’s packaging policy introduces a packaging hierarchy for sourcing such materials, whereby home compostable packaging is the strongest preference. As early as 2001, the supermarket launched compostable packaging for its organic products – trays made from potato starch. More recently, the relaunched Sainsbury’s So Organic range has extended the amount of home compostable packaging being used for fresh fruit, vegetables and salads. Trays, film, labels and nets were also introduced, including a first for UK supermarkets, sourced from non-GM sources of PLAs.

Alison Austin, head of brand policy and sustainability for Sainsbury’s says: “We have been trialling a fully home-compostable non-GM wrap in a bag format for our organic apples and potatoes, the first of its kind the UK, in 140 our of stores in association with customer research. Should this bag be rolled out to all organic bagged produce lines, then potentially it could save 16.5M bags per year going to landfill, a replacement of 140 tonnes.”

Composting provides an environmental solution for consumers if they can be persuaded to place these new types of packaging waste into their composters, rather than sending to landfill with other household rubbish. Recent figures from Wrap show that 34% of households participate in home composting, an increase of 6% from 1997.

More than one million home composting units have been delivered by WRAP to UK householders since 2004. There has also been a significant growth in the proportion of those households that compost both household and garden wastes. Currently rates are about 66% compared with 57% in 1997.

Would a move to more biodegradable packaging be a good thing for the environment? Phillip Ward, director for waste implementation programmes at Wrap sums it up: “Use of renewable resources is a positive but it would be very easy to get things wrong. Mixing plant-based and oil-based plastics in the recycling system would be a problem.

“Sending biodegradable plastics to landfill will just increase methane emissions, which would be bad for global warming. The key will be educating the public so they know the difference and know how to respond.

“While WRAP can help to broker a common approach, those who want to introduce these new materials have the major responsibility to educate their customers.”

The Industry Council for Packaging and the Environment is also keen to develop new packaging materials. Its director, Jane Bickerstaffe, says: “We welcome the current research and development on biodegradable and degradable materials. And we hope this will lead to materials that will provide new functional qualities and additional value for the supply chain and consumers.

“We also believe that no material has a monopoly of environmental virtues. All materials need to be used in a way that will enable goods to be produced, distributed, used and recovered with minimum environmental impact at lowest social and economic cost. This will deliver a truly sustainable packaging and product supply chain.”

Trends

While the UK produces 30M tonnes of household waste per year – and 70% of this is land-filled – the supermarket and convenience sectors produced 4.8M tonnes of packaging in 2002/03. Consumers are now geared up for recycling and home composting. However, there is now a clear need for on-pack messaging on packaging, highlighting if such material can be composted, and stating biodegradability or degradability.

As local authorities are working towards meeting their targets for the EU Landfill Directive, clear labelling on packaging will need to be supported by clear messages on brown wheelie bins to encourage further separation.

With so much research and development currently being undertaken into the areas of biodegradable and degradable packaging, surely it’s time for retailers and local authorities to work together to help consumers make an informed choice. If the future trend is towards more household separation of waste, then education and clear labelling will have a large part to play in reducing the landfill volumes and associated greenhouse gas production.

Becky Toal is director of Crowberry Consulting. Visit www.crowberryconsulting.com