The city is moving ahead with plans to build a leachate treatment facility at the municipally owned Trail Road landfill—more than seven years after city council first floated the idea.
Over the next three years, $9 million has been set aside to study and build the on-site facility, which will need to be operational by 2015, city spokesperson Jocelyne Turner confirmed in an email.
Landfill leachate is water, generally rain or snow, that seeps through garbage and extracts potentially harmful contaminants. It can pose serious environmental risks if it ends up in the groundwater—precisely the concern that Barrhaven residents brought to council in 2004, when the city was planning to build a pipeline under their homes that would shuttle leachate into the sewer system.
Later that year, council directed the city to study on-site leachate management as well. But the plans were shelved after a new stormwater plan at the Trail Road site, combined with a shift in the city’s overall waste management strategy, led to a significant decline in the amount of leachate being produced, said Turner.
No leachate escaped the site in 2010, she said. But current landfill usage rates mean that by 2015, the landfill cap—the impermeable barrier that separates the contaminated waste from the surface—will need to be removed to expand the site. And with the cap gone, snow and rain will collect and need to be treated, she said.
Most of the overall cost—$8 million—has been earmarked for the construction of the treatment facility in 2014. An additional $800,000 in 2012 will go towards “pretreatment” of the leachate, while the final $200,000 will be spent this year on consulting fees “to select the most effective leachate treatment” at the site, said Turner.
Although the city has not revealed what options are currently being considered, one possible idea might be to incorporate some sort of membrane bioreactor system into the facility, says Roberto Narbaitz, an engineering professor at the University of Ottawa.
Such a system would use bacteria to break down the leachate, which would then be filtered through a thin ceramic membrane, leaving hazardous solids behind, says Narbaitz. The relatively expensive technology would give citizens “bang for your buck” at the start of the process, he says. But once the contaminants are no longer biologically reducible, “it’s not so fantastic," he added.
The “most logical” step would be to treat on-site and revive the cost-effective pipeline idea, although many municipalities are now hesitant to go that route, Narbaitz said.
“There’s fear that there may be some toxic contaminants coming from that landfill ... The possibility is there, but there’s a lot of dilution taking place.”
In her email, Turner said the city can use tanker trucks to haul leachate from the Trail Road landfill to the Robert O. Pickard Environmental Centre, the city's wastewater treatment facility, if necessary. No one from the city was available for an in-person interview.
There are citizens living in the vicinity of the Trail Road landfill whose wells are still contaminated by leachate that, in the past, had seeped into the groundwater, says Ottawa riverkeeper Meredith Brown.
Historically, the city has responded to concerns about leachate only because they’re mandated to do so by the Ministry of the Environment, says Brown, whose organization advocates on behalf of the Ottawa River.
“They’re dealing with it because the province makes them deal with it, essentially,” said Brown. “They have no choice. They’re not doing it out of the goodness of their hearts.”
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