You've switched to bioplastic product because you want to reduce your plastic impact. But did you know not all bioplastics are biodegradable? How do they disintegrate? What are bioplastics anyway?
First of all, it's best to understand the types of bioplastics you're using:
PLA: conditionally compostable
PLA is made from fermentable sugar, mostly corn and sugarcane. PLA is popular these days. It's used in biodegradable paper cups, clear cups, salad containers, takeaway cutlery, dental floss and so on. PLA can only be biodegraded under industrial composting conditions, at above 58 °C (136 °F).
PHAs: biodegradable in ambient environment
PHAs are produced from industrial fermentation, using bio-derived feedstocks such as organic waste. PHAs are not widely used (yet!). It can biodegrade in ambient environments, including in the ocean (but that doesn’t mean it’s good for marine health).
PBS & PBAT: conditionally compostable
PBS and PBAT are petroleum-based. They can be biodegraded under industrial composting environment.
Native blends are a mix of materials, including native starch and other polymers. The degradability depends on what types of mix, though it hasn’t been fully studied.
Bio-PE & Bio-PET: not biodegradable
Bio-PE and bio-PET are derived from plant or vegetable sources such as corn and sugar, but have an identical molecular structure to conventional petrochemicals. Because of the same molecular structure, they are accepted at conventional recycling centre. However, they’re not biodegradable.
Bioplastics don’t just disappear.
Most biodegradable plastics will only fully disintegrate at industrial composting facilities. The thicker and stronger the materials are, the harder and longer to biodegrade.
When purchasing a biodegradable product, always check the label. If a product contains trace of plastic, it won’t break down fully with micro-organisms.
So, how to dispose a bioplastic product responsibly?
1. Find out what type of bioplastics it is.
Bio-PE and bio-PET go to the yellow bin (recycling). If it's labeled with the Australian Standards for compostable or biodegradable products, see next step.
Without a label, we suppose they should just be treated as rubbish - which you shouldn't have bought. It's probably greenwashing.
2. Home compost, find an organics recycling service or a local compost
Home compost is the best, because you know where things go!
If you live and work in the City of Sydney areas, you could potentially sign up to their food waste collection trial.
3. If no option is available, red bin (unfortunately)
If none of above is possible, it means most likely your biodegradable plastic bag or coffee cup will end up in landfills or incinerated.
We're yet to find the perfect solution.
Greenhouse gas emissions
Organic wastes release methane, which is 23 times more potent than CO2. Let's face it, how many of us have home compost, and how many councils are collecting organic wastes? Most bioplastics end up in landfills.
Deforestation and GMO
With bioplastics gaining popularity, it could encourage more deforestation and growth of genetically modified crops.
Err .. so should I ditch bioplastics?
Like many innovative solutions (even solar panels!), until we build a fully circular solution – ethical sourcing of materials, understanding material safety, understanding the impact after disintegration, solid infrastructure to support collection and composting, it’s early to say whether bioplastics is a planet saver or not.
Our conclusion is the old saying: reduce, reuse, recycle. Reusing is always better than throwing anything to the bin, any bin.