In the works since 2009, the St-Laurent facility will lock odours inside, slash travel time for grass clippings and apple cores, and process 20 Olympic swimming pools’ worth of waste per year.
Montreal’s first organic waste treatment centre, designed to transform the banana peels and grass clippings of the populace into brown gold, finally celebrated its official opening Monday.
Originally promised 15 years ago along with four other treatment centres, the $169-million facility located in an industrial sector of St-Laurent will be capable of processing 50,000 tonnes of waste per year — the equivalent of 20 Olympic swimming pools full — emanating from brown boxes and garden waste from the western boroughs and demerged suburbs of the island. At present, Montreal’s compost is trucked to facilities in Ontario and Joliette.
“Before, an apple core could travel on average 188 kilometres to be treated,” said Marie-Andrée Mauger, Verdun borough mayor and the city executive committee member responsible for the environment. “Today, thanks to this local infrastructure, the distance has been reduced to six kilometres,” significantly decreasing carbon dioxide emissions. The St-Laurent plant will treat the organic waste of 25 per cent of the Montreal population, she said.
The waste will be converted into 20,000 tonnes of Grade A compost that can be used by the city for its parks and other installations, or sold to farmers or citizens to spread on their fields, gardens and lawns.
Roughly 80 per cent of Montreal’s homes have organic waste pickup. Among residences of eight units or less, about 60 per cent use the composting services, while in buildings with nine residences or more, compliance drops to 30 per cent. The city is aiming to encourage 60 per cent of all residents to use their brown bins by 2025.
Montreal’s second organic composting centre, a biomethanation plant in Montreal East, is slated to open next year.
Beyond creating compost, recycling organic matter has other positive environmental attributes, noted Karel Ménard, director of the environmental advocacy group Front commun québécois pour une gestion écologique des déchets. Half of a typical non-composting Montrealer’s garbage bag is filled with organic waste.
“When we bury organic matter, we create pollution by producing leachate and methane, which is a powerful greenhouse gas,” Ménard said. “When we compost it, we transform it into resources that our agricultural lands so badly need. All this while contributing to the longevity of our landfills.”
On a tour of the sprawling facility on Henri-Bourassa Blvd. W. near Highway 13, city officials explained how the waste is brought in via garbage trucks that are weighed before entering one of four bay doors. To prevent odours from escaping — a major concern among residents when the facility was first proposed — the plant is airtight and kept under negative pressure. All entrances have double doors where the interior one can’t open until the exterior one is closed, so air from the inside never travels directly to the outside. Air exiting the plant is chemically treated in large metal tubes before being exhausted to the outside.
The sifted debris is mixed with wood chip particles to aid with aeration and will sit for three weeks in concrete holding pens where humidity, oxygen and temperature levels are carefully regulated.
“It’s bacteria that is doing the work for us,” said Maxime Roberge, an engineer with the city’s environmental division. “We have to give it the time to do its work.”
Temperatures of the mixture hit about 55 C, killing off pathogens. This is followed by another four weeks in one of nine enclosed, aerated concrete storage units, each with a capacity of 380 tonnes, until the end product is reached: a peaty soil that is safe to the touch and the garden. The whole process takes about eight to nine weeks.
Quebec has 11 similar organic waste treatment centres in operation, with another five under construction.
The separate contracts for the St-Laurent and Montreal East facilities were awarded to Suez Canada Waste Services in 2019. French transnational Veolia Group acquired Suez in 2022 and now has the contracts.
The pandemic delayed delivery of the St-Laurent plant to March 2022 and the Montreal East plant to August 2022. However, a financial dispute between Veolia and its main subcontractor, EBC, temporarily halted work on both facilities in July 2022. Veolia then demanded more money from the city to cover additional labour costs and material and equipment costs due to the combined impact of the pandemic, Russia’s war in Ukraine, factory shutdowns in China due to COVID-19, higher oil prices and a shortage of labour because of all the infrastructure projects in Quebec.
In April 2023, city council voted to approve an additional $32 million to Veolia — about $6 million more for the St-Laurent facility and about $26 million extra for the Montreal East biomethanation plant.
