Solid Waste & Recycling


It's in the Bag

In the last two editions of Solid Waste & Recycling magazine, we published a two-part series by Composting Matters columnist Paul van der Werf about "compostable" plastic bags. We thought i...

In the last two editions of Solid Waste & Recycling magazine, we published a two-part series by Composting Matters columnist Paul van der Werf about “compostable” plastic bags. We thought it would be interesting to follow up on that series with a short technical article about a specific product on the market.

As van der Werf wrote in the last edition, there are standards which govern and test manufacturer’s claims. “The American Society for Testing and Materials (ASTM) D6400 is a standard specification for compostable plastics,” our columnist wrote. “The requirements of this specification include disintegration during composting. There must be inherent biodegradation and no adverse impacts on the ability of compost to support plant growth. Confirmation that a degradable plastic bag is, in fact, compostable requires laboratory testing. This is done on a pass-fail basis. Plastic, whether made from renewable or non-renewable resources, should compost in a manner similar to comparable composting materials.”

“In the United States, the Biodegradable Products Institute (BPI) has developed an certification scheme for compostable plastics. It’s fully endorsed and co-sponsored by the U.S. Composting Council (USCC) and culminates in the use of a seal.”

One product that complies with this certification is BIOSAK Compostable Brown Bags from W. Ralston (Canada) Inc. of Brampton, Ontario (where they’re manufactured). W. Ralston is a supplier to the retail market and offers a range of bags for garbage and recyclables as well as yard and kitchen waste. The company says its “new generation plastic bags meet the ASTM 6400-04 specification for compostable plastic. Products include drawstring tie-bags, anti-bacterial kitchen bags, curbside recycling bags and compostable plastic bags. The products are sold under the company’s brand name and also various private label or control brands.

The company says the bags help keep kitchen collection containers clean, reducing the build up of odors and the need to rinse the container. To the customer, the bags look and function like regular bags. The shelf life depends on storage conditions, but in general they maintain useful properties for a couple of years under normal room temperature and humidity conditions. But the bags biodegrade at the compost site, completely disappearing with no plastic in the compost.

BIOSAK bags are made from Novamont Mater-bi resins based on corn starch and derivatives from vegetable oil. Novamont Mater-bi resins have been used in Europe under different brand names for over a decade. In fact, more than 3,000 European communities use bags manufactured with the same technology as BIOSAK.

Despite being made from special resins, the bags are printable; the company uses a special process that’s non-toxic. Interestingly, rain will not affect the bags, which are waterproof. The bags do not break down in sunlight, either (though there would be some reduction of mechanical properties from extended UV exposure). The yard bags, filled with grass, will biodegrade faster if stored on grass, as this is the most challenging environment. The bags will start to weaken after seven to 10 days, but will hold their load for two weeks. Yard bags filled with leaves and trimmings will begin to weaken after 15 to 20 days. Kitchen bags filled with material will begin to weaken after one to two weeks, so the manufacturer recommends replacement of kitchen bags every five days or so.

For more information, email

Ring supports open paper yard-waste bags

Home Hardware, Country Depot, and True Value stores now distribute the “Magic Ring” — a product designed to deal with the common frustration of collapsing paper yard-waste bags. The device keeps them open and supported while they’re loaded with yard-waste material.

The device exerts outward pressure on the bag, changing the opening into a round semi-rigid receptacle for quick and easy filling. It adjusts to fit all 16 x 12 x 35 paper bags and is made of durable plastic that can be used over and over again. This tool helps homeowners and landscapers with their fall leaf cleanup, and encourages participation in organics diversion in communities across Canada.

Contact Paul Sulentic of Finnsage Inc. at

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