Q Can I really put plastic labelled compostable or biodegradable in the composter?
A Oh, what a tangled web we weave when first we practise to be green. It's hard keeping track of eco labels these days, but in the world of biodegradable plastic it's even tougher. Considering their surge in popularity, a decoding session is in order.
Bio-plastics are generally plastics made from botanical organisms: corn, potato, sugar cane... that kind of thing. Through the wonders of chemistry, they've figured out how to replace the fossil fuels that go into regular plastics with plant-based starches. Still, not all bio-plastic is biodegradable. And not all biodegradable plastic is made of biological organisms. Confused? Take a number.
Some plastic on shelves marketted as biodegradable is actually made from petrochemicals like PET. Locally made Bio-Solo garbage and green-bin bags are a good example. They're not compostable, but thanks to a mystery additive, a plastic that would otherwise stay in landfill for close to eternity dissolves into inert carbon and calcium carbonate dust. But it needs light, heat, air and churning to get there, most of which you don't usually find in landfills. So according to standards bodies this means the plastic is actually degradable rather than biodegradable (see box).
On the other hand, Bio-Solo's new Bag-to-Nature line as well as BioBags and the vast majority of green plastics on the market are made from cornstarch, and most are certified to break down in composters. Note: they're not talking about your backyard variety here, but industrial-strength municipal composters (although I found Brampton-made BioSak bags started breaking down after a few days in my kitchen scraps bin not necessarily a good thing). It's a lovely idea that means we might just be able to have our packaged cake and compost it, too.
There are only two problems with this scene. Corn-based anything isn't without controversy. Much of the water- and energy-intensive crop is genetically modified, and prices are soaring as we fill our ethanol quotas. A growing number of bio-plastic companies (like BioBag) distance themselves from this rep by saying they only source their corn from GMO-free countries (i.e., not the U.S. and Canada). Dow-Cargill also insist its corn-based NatureWorks plastic (used by companies like +1 Spring Water) uses 25 to 55 per cent less fossil fuels to produce, and the rest is offset with renewable energy credits.
Of course, the biggest logistical problem is that not every town has a municipal composting program, let alone one that accepts any form of plastic, no matter how biodegradable. Toronto is non-discriminating and takes it all, though recycling staff say it can be hard for sorters to distinguish a biodegradable fork from a regular plastic fork. Many cities, however, aren't so patient. Halifax refuses any and all bio-plastic. Too much potential for sorting mix-ups, it says. Other areas tell residents to only buy plastics that are certified compostable.
Fear not, earth lovers, there are types of bio-plastic and alternative packaging materials that break down more easily in a backyard composter. Earthcycle food packaging, for instance, (used by the organic produce biz) will biodegrade in your backyard, community or industrial compost and is made from palm fruit fibres left over from palm oil processing a waste product.
Instead of using bleached tree-based paper or polluting plastic, Green Earth paper plates and cups are made with GMO-free sugar cane and wild reeds and are certified by Environment Canada's Environmental Choice program. The bleach- and fossil-fuel-free products use less energy and water, and can be tossed into your backyard composter, municipal green bin or paper recycling bin after your picnic (available at Grassroots on Bloor or Danforth, www.grassrootsstore.com).
It would be nice if all this stuff were made from a local agricultural waste or switchgrass, but those options aren't yet commercially available.
In the meantime, if you must buy a product with packaging or disposable cups and cutlery, is it better to get the biodegradable type? Definitely. Is it still worth buying if you don't have willing industrial composting facilities close by and you have to landfill the stuff? I'd say so, though keep in mind that 40-year-old hot dogs have been found in airless landfills that make it hard for anything to rot. Still the biodegradable stuff is much more likely to vanish a millenium before fossil-fuel-based plastics.
Whatever you do, don't put bio-plastics in with regular plastic recycling they can bung things up. Look for certification symbols that tell you it's guaranteed compostable and/or biodegradable. And remember that the most sustainable strategy is to avoid all packaging and disposable stuff to begin with. But you know that already.
FYI, retailers, restaurants and festivals should track down GreenShift. ca if they want to green their packaging and their business.
Bio-plastic is made from plant-based oils, starches or fibres.
Biodegradable plastic only needs naturally present bacteria to dissolve back into natural elements.
Compostable plastic is certified to break down in a municipal composter as fast as other compostable goods, with no toxic residue. It may or may not break down in your backyard composter.
Degradable plastic (often petrol-based) is designed to decompose under a specified set of conditions, i.e., under UV light.