Businesses and institutions in just six per cent of Montreal's mapped area account for about 100,000 tonnes of food waste sent to landfill each year – half of the total amount from non-household sources in the city as a whole, McGill University researchers found. Food service and retail businesses were found to be the biggest contributors.
Montreal's organic waste collection programs currently focus on households, and waste audits generally only report citywide totals, which can obscure which zones or boroughs produce the most waste, said Xiaowen Ni , lead author and PhD candidate in the Department of Bioresource Engineering.
The researchers' new mapping method could help municipalities target waste-reduction efforts where they would have the greatest impact, Ni said.
"When I started my PhD in 2023, Montreal had committed to divert 60 per cent of its organic waste from landfills. I wanted to help solve this problem," said Ni. "But I found that while the city already has a collection system for residences by borough, they had very little data from the industrial, commercial and institutional (ICI) sectors." Examples of ICI generators include food businesses, restaurants, schools and health care facilities.
More than 14K businesses, institutions considered
To track where food waste was being produced, the researchers devised a new geospatial mapping method that combined federal waste data with information about building locations and size.
They identified 14,508 active businesses and institutions using municipal inspection records and linked them to building-footprint data. They combined this information with food waste audit data compiled for Environment and Climate Change Canada and used computer modelling to estimate food waste disposal across Montreal. The results were then mapped onto 300-metre-by-300-metre grid cells to identify food-waste hotspots across the city.
'Next step is to optimize our waste management'
"This relatively straightforward, low-cost model can help cities frame food waste as a broader, systemic issue that might be happening away from home and related to the businesses and institutions we rely on every day," said Graham MacDonald , study co-author and Associate Professor in the Department of Geography.
The researchers are now working with colleagues in Halifax and Guelph to replicate the model they created. They are also exploring strategies to reduce food waste from the ICI sector, including converting waste into animal feed and neighbourhood-level strategies such as food redistribution.
"I think this is the first step," Ni said. "Now we at least know the probable amounts of food waste and where it's occurring. The next step is to optimize our waste management systems and see what can be done."
About the study
" Quantifying uncertainty in food waste across an urban area: The role of industrial, commercial, and institutional secto rs," by Xiaowen Ni, Graham K. MacDonald, Michael Yongha Boh, and O. Grant Clark, was published in Waste Management.
The study was funded by the Natural Sciences and Engineering Research Council of Canada and Environment and Climate Change Canada.
