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º£½ÇÉçÇø¹ÙÍøhasn’t decided yet what it wants to do with its current landfill, Green Lane, near London, Ont., which isÌýexpected to hit capacity in the next 10 years, but the experience of turningÌýBeare Road Landfill into the park it is today — and that of most other parks built over landfills — suggests it will be neither easy nor quick.

“It does take some effort. It does take money. It does take some planning,”Ìýsaid Larry Conrad, a professional engineer and board member with the Solid Waste Association of North America’s Ontario division. “But there are many examples of successful closures of landfills.”

A need for perpetual careÌý

If , it will still require perpetual care and monitoring, because the garbage is going to stay there indefinitely.ÌýWhile organic waste like food scraps can decompose within weeks, other garbage like plastics or glass can take hundreds to millions of years to decompose.

“You can’t just walk away from this thing after closing it,” said Mark Winfield, a professor at York University’s Faculty of Environmental and Urban Change. “Somebody’s going to have to look after it, essentially forever.”

A landfill that is kept sanitary has two goals: isolate the waste and protect the surrounding environment. When municipalities close landfills, those goals don’t change, regardless of whether it gets a green afterlife like Beare Hill.

Closing and capping

For most landfills, and especially large landfill sites like Green Lane which is 318 acres, closures happen in stages. The site is separated into sections then sealed off as they’re filled while it’s operating, because it’s easier to manage than dealing with the whole site all at once at the end.

Closing sections of a landfill requires capping it, “like putting a lid on top,” saidÌýConrad,Ìýwho is also Peel Region’s former manager of waste operations.

Two of the biggest risks for a closed landfill are emissions, usually methane produced by organic waste decomposing without oxygen, and leachate, which is unavoidable contaminated groundwaterÌýthat has passed through buried garbage and extracted toxic pollutants.

Almost all closed modern landfills have control systems for gas and leachate,Ìýincluding the former Beare Road Landfill site.

“You’re capping that material so it’s isolated from the surrounding environment not only from odours,” Conrad added, but also to prevent rain fromÌýadding to the leachate.

Typically there’s a system of pipes underground that collects thatÌýwater,Ìýpreventing it from getting out into the natural environment, insteadÌýsending it to a treatment plant to get cleaned.

That “lid” on top of all that garbage is typically made up of several layers: impermeableÌýbarrier systems (like a clay liner or a geomembrane), the drainage system that diverts stormwater and collects leachate for treatment. This is then topped with soil, landscaping and vegetation to prevent erosion and pooling — like in Beare Hill Park.Ìý

It’s a process demanding studies, consultations and applications, so it can take years, and isÌýregulated by Ontario’s Ministry of the Environment, Conservation and Parks. The costs to close them fall on the municipality operating the landfill.

When landfills reach 90 per cent capacity or are within two years of closing, whichever comes first, cities have to submit a detailed closure plan to the province for approval. This plan outlines all closure activities including how to manageÌýleachate and gas emissions, post-closure site use, as well as how it will be monitored and maintained long term.

In the case ofÌýBeare Road Landfill, all of that, plus the park’s development, took four decades.

In an email to the Star, ministry spokesperson Gary Wheeler said because each landfill in Ontario is unique, each closure report will be different — as will its timelines and costs.

“The closure report may be refused or returned … if the proposed work is not protective of the environment or contravenes environmental protection standards,” WheelerÌýsaid.

Risks of rotting garbage

Wheeler notedÌýthat leachate can seep into groundwater or even migrate beyond the landfill’s property line and contaminateÌýoceans, lakes, rivers or streams in neighbouring communities.

Before the 1980s, landfills were almost an unregulated activity, said Winfield.Ìý“They were literally just a hole in the ground. Cities threw whatever in, then bulldozed some dirt over the top.”

Under current rules, “you have to pump out the leachates accumulating at the bottom of the landfill,” said Winfield, who is also a former adviser to the federal and provincial environmental commissioners.Ìý“You may need to have monitoring wells as well to make sure that there is no leakage.”Ìý

The methane needs to be captured, too, because it’s flammable and a very potent greenhouse gas. Pipe-like wells that stick out of the ground connect to an underground network that collects the methane. Older versions burned the collected gas, like what was once happening at Beare Road.

“What commonly happens now is you collect the gas and clean it,”ÌýWinfield said.Ìý“Then you have renewable natural gas, which can be put into the gas grid or used to replace fossil natural gas and stuff that’s come out of the ground.”

Fuelling the gas grid is what the former Beare Road site did long before Beare Hill Park was built over it. The city’s gas control system in 1996 started collecting landfill gas then transporting it to generate electricity at a nearby power plant. This stopped inÌý2014 “due to insufficient gas levels,” a city spokesperson said.

In 2016, the province approved a “passive gas management system” to allow the gas from the Beare Road Landfill site to vent through the soil cap ever since. “Today, the site continues to be monitored,” the spokesperson said.ÌýMeanwhile, the power plant isÌý.Ìý

“That’s normal,” Conrad said. “There’s a lot of gas in the early life of a landfill site. But as it ages, not a lot generates.”

Some landfills cause problems

But even with all the regulations around closing a landfill, there are no guarantees, according to Theresa McClenaghan, a lawyer and executive director of the Canadian Environmental Law Association, which also works on landfill cases for community groups and First Nations.

McClenaghan said that a closed landfill’s methane has in the past seeped through fractured bedrock or the clay-lined cap and into nearby buildings or homes with disastrous results.

“In Kitchener, there was a notorious landfill on Ottawa Street where the city had to buy back some houses and tear them down because of methane seepage around the landfill,”ÌýMcClenaghan said. That former landfill site, which closed in 1978, was turned into the $4.7-millionÌýMcLennan Park, which opened in 2011.

Even with today’s tighter regulations, closed landfills can pose problems if managed poorly, McClenaghanÌýsaid. A landfill in Napanee was closed in 2011, but excessive leachate leaks afterward contaminated nearby drinking wells. “It’s an ongoing issue,” she said.

In Hagersville, the former Tom Howe landfill, closed in 2015, has problems with gas emissions, according to McClenaghan. “It did have landfill gas collection installed … but whenever I happen to go by it’s poorly controlled … There is a lot of methane.”

Cost of a green afterlife

Municipalities are limited in what they can do with a former landfill. Building anything on top of what is decomposing garbage would be potentially fraught: the foundation could shift over time.

Outdoor parks are easier to manage if problems like cracks in the cap or uneven flooring appear, said Conrad, but any change would beÌý“minute. It’s not likeÌýyou’d be stepping off a cliff.”

Even converting a landfill into an easily monitored green space comes at a price for the municipality. It cost about $600,000 to decommission the Beare Road landfill, and continues to cost tens of thousands of dollars per yearÌýto monitor it. It cost the city a further $1.5 million to turn it into Beare Hill Park, which opened in 2022.

Mississauga spent $13 million to transform the Britannia Landfill, which closed in 2002, into the 200-acre BraeBen Golf Course, which opened a few years later.

Toronto’s former primary landfill, the 380-acre Keele Valley Landfill which closed in 2002, is slated to become part of Vaughan’s North Maple Regional Park, a futureÌý900-acreÌýgreen space for sports and recreation rolling out in phases.

Neither Mississauga nor º£½ÇÉçÇø¹ÙÍøcould say how much it cost in total to decommission Britannia orÌýKeele Valley. In the case of Keele, a spokesperson for º£½ÇÉçÇø¹ÙÍøsaid repurposing the infrastructure for a park “involves a complex, regulated process requiring provincial approvals, environmental studies, public consultation, all with their own financial considerations,” so a final cost has yet to be determined.