More than 99 per cent of the waste from transportation construction sites in Calgary routinely gets recycled, according to the city.
Between 70,000 and 150,000 tonnes of construction and demolition waste materials are generated each year, and for the past nine years, the city has required contractors to report just where those materials are going when they're hauled away from road and bridge projects.
In 2012, about 95 per cent of the waste was diverted from landfills, said Ethan Askey, manager of sustainability strategy in the city's transportation department.
"We had no idea. We knew we recycled, repurposed a lot of material before 2012, but we really wanted to build out our environmental programs and … have a firm grasp on what we're doing," said Askey.
With a renewed focus, that number has since risen to over 99 per cent.
"Most of our materials are pretty readily recyclable," said Askey. "There are markets for them. Concrete, asphalt, steel are relatively straightforward to process and reuse."
Advances, such as the use of reclaimed asphalt pavement (RAP), make using repurposed materials more appealing.
In fact, Askey said the only material from construction sites that cannot be recycled are some types of litter and contaminated and potentially hazardous items.
"We excavate sites and it's a bit of a crapshoot as to what you'll find there," he said. "Sometimes there's old barrels buried in there, other litter. We find old railway ties that are creosote-treated, for example, where we used to have train lines back in the day."
Recycling is a big cost-saver for city
Askey said that recycling materials, rather than hauling them to the landfill, saves the city money each year.
He said they avoided $3.5 million in charges last year, based on tipping fees and truck hauling costs.
It also means landfills can be used longer before reaching their capacity.
And though Calgary's road and bridge construction sites have their recycling system figured out, their efforts can help more broadly with making transportation projects more sustainable.
"What we can do is look at the things we're doing well here in Calgary and help others through our discussions and our sharing of best practices across the country," said Askey.
With files from Scott Dippel.