From plastic to potting soil: How compostable bags fight climate change

2009-10-01

Industries around the world are exploring the capture and storage of their carbon dioxide emissions, rather than continuing to release them directly into the atmosphere along with other harmful greenhouse gases.

Automotive manufacturers are working to create and market electric and other environmentally friendly automobiles to reduce their carbon footprint.

Scientists are developing products that help to decrease carbon dioxide emissions from waste that is rapidly filling landfills – including products like vegetable-based polymers that mimic the properties of plastic, but deteriorate rapidly in normal compost settings.

It’s not that plastic bags are filling up the landfills – the Canadian Plastics Industry Association reports that plastic bags make up less than one per cent of residential solid waste by weight. However, landfills release up to 38 per cent of Canada’s methane gas emissions, which is over 20 times more effective in trapping heat in the atmosphere than carbon dioxide over a 100-year period and remains in the atmosphere for approximately 9-15 years. And food waste accounts for over one third of what’s thrown into Canada’s landfills.

Reducing what goes into landfills would help decrease Canada’s greenhouse gas emissions; diverting food waste through composting programs is one way Canadians can do this, however, many are reluctant to compost because of concerns about cleanliness. Compostable plastic bags can help by offering a cleaner way to store and dispose of food waste, making it more attractive for the masses to participate in composting programs.

In April 2007, the Region of Peel introduced its Organics Recycling Program to continue its journey towards a goal that will see the Region divert 70 per cent of its waste from disposal by 2016. Fast forward two-and-a-half years and the Region now diverts just over 50 per cent from its local landfill, up from 44 per cent before the program began.

“We have 45 to 50 per cent of households participating,” says Dave Gordon, Manager of Waste Planning with the Region of Peel. “We would like to see that grow. We introduced our blue box program in the late 80s, early 90s, and 90 per cent now participate in that.”

In the fall of 2007, shortly after the Region’s Organics Recycling Program began, it banned the use of non-certified compostable plastic bags.

“The decision came after long debate at Council on whether to allow plastics or not as they contaminate the finished product,” says Gordon. “It was decided in the end to allow paper bags and certified compostable bags. They do break down in the composting process and have no impact on the finished product.”

He adds that while they do not have any empirical data on whether the bags are improving the participation rates in the program, he does feel it gives people more access to the program in a way that won’t impair the end product. And since they were introduced, the cost of the bags – while still more expensive than conventional plastic bags – has decreased, making them all the more attractive as an option for consumers.

“This was a relatively new technology when we launched,” says Gordon. “We are hoping as the industry rolls out, the cost will go down.”

Of course this raises the question of how does one know that bags are actually compostable.
In September 2007, the Bureau de normalisation du Québec (BNQ), which is accredited by the Standards Council of Canada (SCC), became an official certification agency for compostable plastic bags when it published its compostable plastic bags certification program (BNQ 9011-911).

A year later, the International Organization for Standardization published its standard for the Specifications for compostable plastics (ISO 17088:2008), which looks at the physical properties of compostable plastic and ensures they are compostable in a certain period of time and that the by-products will not contaminate compost. ISO 17088 was in development at the same time BNQ was building its program, and is actually what BNQ based its program on.

Sylvain Allard, a standards agent with BNQ, feels standards are contributing to compostable plastic bags being used more widely, especially as more companies start producing them. There are currently five Canadian companies certified under BNQ’s certification program to use the specific certification mark to promote their compostable plastic bags, and more are in the process of being able to do so.

For now, these products are being used where there are municipal compostable programs. However, BNQ is currently working on modifying its program to be adopted as a national standard, not only for plastic bags, but for all types of compostable plastic products including plates, forks, knifes and glasses.

“We don't know if the compostable plastics will replace plastic in our day-to-day products, but our partner in that program, the Composting Council of Canada, is promoting the use of those products,” Allard says. “Will the public go in that direction? We don't know. Only time will tell.”

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This article first appeared in Volume 36 of CONSENSUS Magazine, 2009.  The information it contains was accurate at the time of publication but has not been updated or revised since, and may not reflect the latest updates on the topic.  If you have specific questions or concerns about the content, please contact the Standards Council of Canada.

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