The City of Toronto and the surrounding Greater Toronto Area has an outstanding organic waste curbside collection program called the Green Bin Program. I was interested in visiting any of the local organic waste processing facilities while in the Toronto area but unfortunately, I wasn’t able to tour any of them as an individual. However, I was able to connect with a gentleman named Bob Kearse, the Senior Engineer at City of Toronto, Solid Waste Management Services. He answered my questions about the Green Bin Program as it functions currently and he also provided me with information about the processing facility expansion projects underway.
Amazingly, 90% of single family homes (about 510,000) participate. Research shows that an average of nearly 450 pounds of organic waste is collected per household each year. That means the Green Bin Program diverts 114,750 tons of waste from landfills each year and as the program is rolled out to apartment, condo, and co-op buildings, the waste diversion rates are set to rise.
Food scraps, soiled paper, diapers, sanitary products, and even pet waste is accepted because the material is processed at high enough temperatures that pathogens (disease-causing organisms) are destroyed. The waste is collected from the curb and trucked to facilities where it is first preprocessed to removed debris (e.g. plastic bags and plastic diaper materials, which are extracted and sent to the landfill). The sifted pulp is then put through anaerobic digestion—a process by which naturally occurring anaerobic bacteria break down the organic material in an oxygen deprived vessel. The resulting “digestate” is then trucked to external contractors at secondary facilities where it is processed by aerobic composting. The final product, which is certified by Canada’s Ministry of the Environment, is used on farms, in parks, and in residential gardens.
Toronto’s primary processing facility is the Dufferin Green Bin Facility. They currently process 40,000 tons of waste per year, which is less than half the waste collected from participating residents. The rest has been sent to facilities outside the Greater Toronto Area, but the city is currently working to increase it’s local processing capacity with the expansion of the Dufferin facility and construction of an entirely new second facility—a 75 million dollar project. Above is a photo of the construction at Dufferin. In the foreground is a view of the roof support struts in place on the new anaerobic digester. The tank is about 60 feet in diameter and 100 feet tall. In the background “media” is being poured into the new biofilter, which uses microorganisms for air filtration and purification—in other words, it’s job is to remove odor and dust pollution. The City also plans to make use of biogas—the other main product (besides digestate) of anaerobic digestion, to generate power. Bob explained that these projects resulted from “the push from council to improve on what we’re already doing well.”
I’ve written a bit in earlier posts about scaling in and out on the garbage crisis—thinking about both macro and micro issues in waste production. Meticulous research on toothbrush bristles and soap ingredients can at times be mind-numbing, while learning the specs on Rhode Island’s ever shrinking landfill capacity or reading about the Great Pacific Garbage Patch can leave me feeling hopelessly overwhelmed. It’s been important for me to try to aim for some balance between both modes. I am fascinated by the large scale waste management efforts in place today. I often think about where we’d be without landfill, recycling, and compost programs. The data I collect on these operations informs the decisions I make in my daily life (the small realm I can control), such as what I choose to consume (and how), the way I choose to move about, and how I care for the objects and company I keep.
Learning about commercial composting processes makes me look at my backyard operation with a new appreciation. I am so grateful to be able to keep my little bin behind my apartment and I recognize that it’s a privilege many people who live in a city don’t enjoy. My heap can’t breakdown meat scraps or diaper waste, but these are not bi-products of my current lifestyle. For now, simply balancing carbon (dried leaves, cardboard, and paper) and nitrogen (fruit and vegetable scraps) is a self-sufficient and efficient system that keeps my organic waste out of the landfill in Johnston.
Photo courtesy of the City of Toronto website.