Solid Waste & Recycling


Ontario composting guideline released for comment (November 30, 2009)

Ontario’s environment ministry has released a draft guideline for compost operators entitled the “...

Ontario’s environment ministry has released a draft guideline for compost operators entitled the “Guideline for Composting Facilities and Compost Use in Ontario.” The guideline includes best management practices and guidance for compost facilities and municipal waste managers.

Some of the areas addressed include locating and design of facilities and equipment use and operating procedures.

The ministry is proposing new compost categories that would allow the composting of additional materials (such as septage, sewage biosolids and pulp and paper mill biosolids). The guideline sets out quality standards for each category of compost, as well as establishing restrictions for the use of each category based on the quality of the product and the risks associated with its application. The ministry is proposing amendments to Regulation 347 under the Environmental Protection Act to give legal effect to the new compost standards and application restrictions set out in the guideline.

The 134-page environment ministry document released for public consultation includes specific rules for compost, establishing three different grades: “AA” is best, and can be used in gardens and directly with plants; “A” is second best, as it needs to be mixed with soil; and, “B” which is suitable only for landfill daily cover or roadside applications.

The new guidelines focus attention on the quality of the product emerging from the province’s compost facilities. Questions about quality have been in media headlines due to the discovery of contamination in some compost materials produced by municipal programs and independent contractors to large cities. The draft guidelines require that materials be properly finished or cured before leaving a composting plant. The new rules encourage composters to ensure the material has the right mix of nutrients and imposes tight restrictions on sodium levels before distribution to the public.

The release of the guidelines is timely. Toronto is planning to build two new processing plants at a cost of about $65 million to complement its existing Dufferin organics facility. The city is achieving good participation in its popular green bin program, but has experienced a series of problems with outside contractors; there’s insufficient composting capacity in the province and exporting organic material to Quebec has also been fraught with problems due to technical problems and the closure of composting plants in that province.

Many municipalities are establishing green bin-style organics collection programs and face similar challenges in determining the best technical solutions. Experts have clamored for years for guidelines that are reasonable and that set achievable targets, but which also encourage a quality product.

The ministry guidelines warn against the risk of allowing residents to use non-compostable plastic bin liners and also against the inclusion of diapers. Allowing certain plastics poses technical challenges at the compost plant and plastic shards may remain in the final product, meaning it may only be suitable for low end-uses. The document states, “Without appropriate mechanical processes specifically designed to manage these materials, diapers and sanitary products often remain mostly intact in the final compost product … Diapers have also been identified as a contributor to odour problems at compost facilities where accepted.”


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