Compostable vs Biodegradable?
3 Truths No One Tells You About Biodegradable Plastic Bags
What is Biodegrable Bags?
Supermarkets distributes biodegradable plastic bags telling you to reuse the bags and you feel really good reusing them for trash. Or you choose to buy biodegradable trash bags rather than normal trash bags Who doesn’t want to help the environment, right?
If you’re like me, you’ve preceded your purchase of biodegradable bags with a well-intended thought process that goes something like this: If I buy this bag, my trash will magically go back to nature — an ashes-to-ashes-dust-to-dust sort of thing — which makes me happier than imagining it rotting in a landfill. Not exactly how it should be.
1. Biodegradeable plastics cannot biodegrade if they are buried in the landfill or left in the sea.
In fact, the Environmental Protection Agency (EPA) requires landfills to block out air, moisture and sunlight which are the crucial elements for proper biodegradation.
It’s well-intentioned but wrong. A lot of plastics labelled biodegradable, like shopping bags, will only break down in temperatures of 50C and that is not the ocean nor landfill. They are also not buoyant, so they’re going to sink, so they’re not going to be exposed to UV and break down.
2. Biodegradable plastics typically can’t be recycled with other plastic items.
A 2007 study which evaluated two brands of oxo-degradable and hydro-degradable bags, indicates that neither type of bag are perfectly compatible with the traditional plastic grocery bag recycling stream, which is typically low-density polyethylene (LDPE).
They are related to those little numbers you see on plastic bottles.
A №1 and a №2 can be recycled together, but throw in a biodegradable bag — a №7 plastic — and you’ll contaminate the whole “recyclable” load.
“If a №7 plastic is mixed in and melted down with plastics labeled №1 or №2, it would contaminate the entire load because the chemical make-up of biodegradable bags are so different.”
It’s like washing a bagful of white clothings and there’s a little dark blue knickers hidden somewhere among them. You wash them in 90C and out comes you ‘natural’ blue stains on all your whites.
3. Biodegradable bags can harm the environment.
Yes, you read that right. When biodegradable trash bags wind up in landfills, decomposition happens at a much slower rate than if the trash were exposed to air, light and moisture.
Usually, nothing biodegrades in a landfill. But if biodegradable plastics do break down in this oxygen-free environment, they’ll emit methane, a greenhouse gas 23 times more potent than CO2.
As a result, methane gas gets released into the atmosphere. In fact, pound for pound, methane contributes 20 times more to the greenhouse effect than carbon dioxide over a 100-year period.
So, what can an eco-minded person like you do?
Simple:
- Bring your own shopping bags to cut down usage of plastic bags.
- Buy compostable trash bags instead of biodegradable bags because compostable bags are truly compostable.
In other words, you can’t just throw a biodegradable trash bag on your compost pile and think it will decompose. It can’t; the temperature won’t get hot enough. But compostable trash bags will turn into compost over time. As to why that’s important, it comes down to the knowing the benefits of composting.