By Yvette d'Entremont - The Weekly News
The Upper Sackville landfill may have closed more than a decade ago, but maintenance at the site is ongoing.
An HRM tender was recently issued for "the correction of erosion and cap integrity issues." Coun. Brad Johns, whose district includes Upper Sackville, said the work is all part of the expected long-term maintenance involved with the closure of a landfill.
"What happened is there's a life to a landfill. Particularly with the older landfills, they're designed so water leaches and seeps through all that garbage," Johns explained. "You get leachate, a chemical junk ... You're looking at 20 to 25 years before that (leachate) is stopped."
When the landfill closed in 1996, Johns said a sum of about $1.5 million was set aside to ensure the landfill would be "properly" closed. The recent tender will, in part, address the need to place another layer of soil over the material at the site.
"Over a year or two some soil (at the landfill) will erode, and this is part of the ongoing planned maintenance in the long term of closing that landfill out," Johns said.
The cap integrity mentioned in the tender refers to caps covering onsite wells used to catch methane gas.
"There are actually wells drilled in the soil to release the methane and the cap catches the methane," Johns explained.
"To allow the gas to escape, there are wells. So this is ongoing maintenance designed to make sure the wells are maintained."
In 2007, Highland Energy began collecting the large quantities of methane gas being released by the four million tons of garbage that were buried at the former Sackville landfill site from 1978 to 1996.
Johns said until Highland Energy began operating, the former landfill served as the greatest source of green-house-gas emissions owned by the municipality. When released into the environment, methane is considered 21 times more destructive than carbon dioxide.
The onsite collection prevents methane from escaping into the atmosphere. In addition, the amount of methane gas produced at the site is enough to run generators that can supply electricity to 2,000 homes.
ydentremont@hfxnews.ca
