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Wood chips and beet brine used on wintry roads in some parts of the country, but not here in Sudbury

But Sudbury is part of a group of cities that meets regularly to look at new technologies, techniques
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(File)

Greater Sudbury is always looking at alternatives to road salt, city officials said this week, after a recent Canadian Press story outlined what other cities are doing to cut back on the use of the effective – but environmentally harmful – chemical.

For example, Saskatoon is testing wood chips to improve traction on roads, the story said. Several Canadian cities, including Calgary, have been experimenting with a mixture of sugar beet molasses and salt brine as a de-icing agent.

Edmonton, meanwhile, has been testing an anti-icing calcium chloride brine spray on its roads before plowing. It hopes the alternative to sand or rock salt will save money, reduce the environmental impact and improve safety by ridding streets of snow and ice more quickly.

In addition to the anti-icing project, Edmonton has begun using GPS technology on its heavy equipment to better monitor where melting and abrasive products are spread. The goal is to reduce the amount of material by up to 30 per cent.

Randy Halverson, Greater Sudbury's manager of operations, said the city has taken several steps to minimize the use of road salt, including monitors on salt trucks that ensure the right amount of salt is used in the right areas.

“We have very specific application rates,” Halverson said. “We calibrate our trucks to ensure that we're getting the right amount of product out. 

“So effectively you have the ability to dial in the amount of salt that you would like to on the road to very specified amounts ... based on the conditions of the road.”

About 25 per cent of the city's roads are salted in winter, with the rest getting pickled sand, which contains about eight per cent salt.

The city was able to reduce its use of road salt by as much as 20 per cent when they began pre-treating the roads with a salt brine. 

“When you discharge salt off the back of a spreader, it hits the ground and it bounces – it literally bounces and scatters all over the place,” he said. “When you introduce some salt brine with that, it sticks on contact with the road. So you get significantly less scatter.”

That means instead of spreading across a wide area – ditches, waterways, etc. -- the salt sticks to the brine. 

“By using a salt brine as a pre-wetting agent is we're able to significantly reduce the amount of salt up to 20 per cent,” he said. “The brine on the surface of the road is actually interacting with the surface and creating a layer that doesn't allow the snow to bond. So the snow comes on top and the brine melts off the snow, making it into slush.”

Edmonton uses a similar approach, but their brine is calcium based, and not harmful to waterways or vegetation. 

“And one of the nice features of calcium chloride (brine) is it works at a lower operating temperature,” Halverson said. “It it generates more heat effectively.” 

On the downside, it's far more corrosive to vehicles, he said, and is far more expensive. Where road salt is about $90 a metric tonne, calcium chloride is $660.

In a report to the city's operations committee last May, Halverson outlined the current trends in road maintenance, and listed the chemicals other communities are using to try and move away from salt.

The report listed 11 different compounds being used by other communities. The city has looked at them, but Halverson said either they are ineffective or too costly.

“Alternatives to road salt are generally prohibitively expensive, not appropriate for use on public roadways, unproven in a large scale operation and, in many instances, an alternative form of salt,” the report said. 

Since 2005, the Greater Sudbury has had a salt management plan, a document that outlines how the city is working to minimize the environmental impact of road salt. It's updated every two years. The city also belongs to a group of municipalities that meets regularly to talk about the latest trends and products.

If there's something new that would allow them to effectively use less salt, he said they would be very interested.

“We're always looking at different things, and there's often new products on the market,” Halverson said. “So we have a look at them and we evaluate them.”

“We want to have like a 'continuous improvement' approach to any of the winter maintenance activities that we do, so we're always interested in looking at things like new products.”

The city's baseline for road salt is about 20,000 metric tonnes a year, and that amount rises or falls largely based on the weather, he said. For example, milder weather in 2015 allowed the salt usage to drop to about 12,000 tonnes, but rose to 22,000 tonnes in 2017, again because of a change in the weather.

“So the type of winter we have is going to dictate the amount of salt,” Halverson said.

While road salt prices have spiked this year, he said the city is protected from big increases because they have multi-year contracts that guarantees the price ahead of time.


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Darren MacDonald

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