Biodegradable & Compostable Plastics

“There are certain conditions, like temperature and moisture, which affect how well a plastic breaks down. This means a biodegradable plastic will not simply break down wherever it ends up. If it is not disposed of correctly or ends up as litter, it might not break down at all.”


“This is why biodegradable plastics are not effective yet because they must be disposed of correctly or they may never break down as claimed” said Rowan Williams, president of the Australasian Bioplastics Association.


"the majority of products currently available are labelled 'compostable', meaning they need to go to a commercial composting facility."


So if you are lucky enough to live in a regional area like Bunbury in WA, which is one of around 150 regions with commercial composting facilities, the compostable biodegradable bags can be very useful for food scraps and dog deposits. But if you put them into land fill with general rubbish, they will behave like a standard plastic bag, as the conditions do not help it to break down.


Choice has put together a guide to help you know what terms to look out for:

  • Biodegradable will biodegrade, but generally not as quickly as compostable plastic. Look for products that state they are 100% biodegradable and show the disposal method.
  • Compostable will biodegrade in a commercial compost facility. Look for the Australian Standard number (AS 4736-2006) on the label.
  • Home Compostable is the best option if you have a home compost bin. Look for the Australian Standard number (AS 5810-2010) on the label.

But watch out for these:

  • Bio-or plant-based means the plastic is made from plant materials rather than fossil fuels, but this doesn't necessarily mean it is biodegradable or compostable.
  • Bioplastic is a confusing industry term that has two meanings – it could mean the plastic is biodegradable/compostable or that it is made from plant materials. Ignore this term, as it's not reliable.
  • Degradable is neither biodegradable nor compostable.

Biodegradable Vs Degradable

Something is considered biodegradable if it can be broken down by living things, usually by microorganisms like bacteria and fungi. 

Degradable products do not require living organisms to break down. Instead, chemical additives are used in the plastic to make it crumble more quickly into smaller pieces of plastic than it would otherwise. Thus, the plastic pollution problem is still there if not worsened as smaller pieces of plastic litter can be more hazardous to wildlife.


On a positive note, researchers have discovered a bacteria that can break down all plastics in a zero oxygen environment. This is significant, because if implemented in landfill sites where plastics are compacted underground, i.e. zero oxygen, then it could still break down. This causes other problems for land management in terms of pockets and voids developing underground resulting in sink holes and ground collapses, but this could, in theory, be managed as per current technologies used in mining.


No Plastic Bags….what do I use for my kitchen rubbish bin?


Just consider this scenario:


In the kitchen, you have a scrap bucket, a compost bucket, a worm food bucket, a chook bucket, the dogs breakfast bucket….call it what you want.


In this bucket you place all of your food scraps and anything that is wet or able to be put straight into the ground like food based scraps, paper towel ect.


Now what is left to go in your kitchen rubbish bin? Paper and plastic…..anything else?


Now imagine if in this scenario we got super organised and had two other buckets, tubs or bins. One for the recyclables and one for soft plastics. Just about everything can be rinsed and put into these two bins/tubs. Granted you will need to take the soft plastics to your nearest Woolworths or Coles store when it is full, but this should only highlight how much plastic there is going around. Woolworths have committed to have Redcycle bins available at EVERY single Woolworths store by June 2018.


So what is left to go in your kitchen bin now…..that you need to have a plastic liner for?


Perhaps bottle tops, jar lids…..well did you know if you collect these and bundle them together, say put them inside of a glass jar, they can be put into the recycling as well.


Now there are always going to be times and things which are too difficult or greasy, that you can’t be bothered cleaning for recycling, and are best put into the waste. In this case, you can always use some of the soft plastics from other packaging to wrap the item in and drop it in the kitchen bin….or maybe take it straight out to the wheely dirty bin outside.


What’s the worst that could happen. Something leaks, makes a mess and you need to hose out your kitchen bin…is that so terrible?


As mentioned earlier, the big benefit about doing this separation process, is it highlights how much of each type of waste your house goes through. Now recycling is the first step and has to be better than everything to going to land fill, but the next step is to start looking for ways to reduce the amount of stuff being recycled. Find package free options, make your own, reuse….it becomes a game to reduce and minimise waste, and all of a sudden, you are a full-blown greenie!!

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