When you start thinking about which plastic bag alternative to use, you might notice there are a variety of 'degradable' and 'biodegradable' bags on the market.
Biodegradable plastic bags are often made from farmed products like cornstarch, which, in the right conditions, will break down into elements like carbon dioxide, water and methane. Biodegradable bags are generally best suited to composting and may contribute to methane emissions if sent to landfill. To meet international standards, bags need to compost within 12 weeks and fully biodegrade within 6 months. Biodegradable bags are not suited to recycling.
Other degradable plastic bags break down primarily through the reaction of a chemical additive to oxygen, light or heat and are also known as 'oxodegradable' bags. Best suited to landfill disposal, they are also likely to survive long enough to present a threat to animals if littered. As it may take time for them to break down completely, they may pose a threat to animals who mistake the pieces for food. These bags can be recycled.
It's important to understand the difference between these bags and the impact they can have on the environment. Replacement of normal plastic with degradable and biodegradable bags is not encouraged by governments as part of the planned phase-out, as neither is a solution to plastic bag litter.
Standards Australia and Europe is currently developing Australian Standards for degradable (including biodegradable) plastics. In time, these may help you to be sure the bags you're buying are as degradable as they claim.
Meanwhile, ask your supplier some detailed questions to make sure you get what you want:
- What are the bags made from and how do they degrade?
- How long will the bags take to break down in their intended disposal environment?
- Will my customers know how to dispose of them (e.g. are they clearly labelled as compostable or landfill compatible?
- Can the supplier provide you with data from any testing completed to back-up their claims about degradability? For example, does the product pass relevant international Standards, such as the European composting/biodegradability standard known as EN 13432.