You don’t find too many people who get excited about garbage but Michelle Jelinski, P.Eng. can barely contain her excitement about her role as Environmental Operations Manager for the City of Saskatoon. Some garbage collectors may give themselves airs by calling themselves “sanitation engineers”, but Jelinski’s job – and passion – actually involves applying the principles of engineering to waste management.
In her presentation at the Annual Meeting, Jelinski noted the Saskatoon landfill was built in 1955 and holds a staggering six million tonnes of waste. At that size, the facility not only holds waste but also produces it in the form of contaminated water and landfill gas which are a constant challenge for the City to keep under control. One of the landfill’s most innovative features is its landfill gas collection and power generation plant which has turned a problem into a revenue source for the city. This facility reduces greenhouse gas emissions by the equivalent of taking 10,000 cars a year off the road. The gas generated by the landfill gases is enough to power approximately 1,200 homes.
For all of its innovation, the site faced the same ultimate problem of any product of engineering – lifespan. In 2010, the landfill had only 10-15 years remaining on its projected lifespan.
“The costs to replace a landfill are massive,” Jelinski said. “First there’s the process of shutting down the old site. Environmental regulations require us to monitor the environmental impacts there for at least 35 years and likely much longer, at a cost of over $200,000 a year. Then, building a new site takes a decade to complete and is projected to cost $100 million all in. Plus, since a new site would be further away from the city than the current one, the ongoing transportation and operations costs would be higher.”
It, made more sense for the city to try to extend the life of the current site. Under the 2010 Landfill Management Plan, the city improved compaction methods, made the side slopes steeper so garbage could be piled higher and made some relatively modest expansions to the site by acquiring neighbouring land. All told, the improvements have increased the landfill’s lifespan by over 40 years.
Even with these enhancements, the city’s Environmental Operations department can’t rest on its laurels about long-term planning. Any number of risks could arise to undermine the current plan.
“What if our population suddenly grows more quickly than expected? What if a regional landfill shuts down and that waste is diverted to us? What if, when it comes time to build a new landfill, we can’t get the environmental approvals to proceed (which has happened in other places)?”
To manage these long-term risks, waste engineers are looking increasingly to waste diversion – quite simply, creating less garbage that needs to go to the dump. Recycling programs are an obvious and well-established example of this but there is more that can be done, Jelinski says.
“Out of everything that gets sent to the landfill, only about 23 per cent of it is actually garbage – totally unusable waste. Fifty-eight per cent is organics that could be composted. Ten per cent is unrecycled recyclables. Another 9 per cent is assorted other reusable items – appliances that could be refurbished, scrap metal, electronics from which precious metals could be reclaimed and other items.”
The City of Saskatoon has set an aggressive target to achieve 70 per cent waste diversion by 2023. Its current level of diversion is 23 per cent.
“That’s going to be a bit of a stretch but it’s important that we set our sights high.” The recycling component of the city’s waste diversion plan is already in place and requires little more than continued promotion to increase compliance.
For organic waste, the city has taken a few modest steps. There is a composting depot where residents can drop off organic waste. The city runs annual Christmas tree drop-off centres. It has also started a residential “green bin” curbside collection program for yard waste but, unlike some other cities with residential green bins, Saskatoon’s program is optional and users pay a fee for the service.
The city also operates drop-off facilities for other recoverable waste such as scrap metals, appliances, used oil and antifreeze, propane tanks, batteries and bicycles. Jelinski’s department also runs promotional activities such as the 30 Day Waste Challenge which featured waste reduction information on the city website as well as automated educational emails on the topics of recycling, composting, reduction and diversion. Looking down the road, Jelinski sees three major opportunities to enhance Saskatoon’s waste diversion efforts.
The first would be a mandatory green bin program without a special fee but with the capability of handling both yard and food waste.
Second is a vision she calls “Recovery Park,” a sort of landfill alternative that would offer a “one stop shop” for voluntary recycling and waste diversion.
Finally, her department has floated the idea of changing waste collection to a civic utility model, or “pay-as-you-throw” as Jelinski calls it – a sort of garbage equivalent to a carbon tax. Residents would be charged according to the amount of waste collected, giving them a financial incentive to seek out waste diversion alternatives.
But no matter how efficient Jelinski’s department is at extending the landfill’s lifespan, sooner or later it will have to close and the city will have to consider how to use the reclaimed land. Because of the need for ongoing long-term monitoring, this land obviously could not be turned over to development even if that were feasible or desirable.
Other jurisdictions’ solutions have bordered on the ridiculous. One city in the US converted its former dump into a tourist attraction called Mt. Trashmore, which for a while included play slides until there were some incidents with exposed rebar. Edmonton built a golf course over its former dump but golfers can’t smoke on the course for fear of igniting landfill gases.
Saskatoon is aiming for a more modest solution with plans to cover the landfill, whenever it eventually closes, with vegetation so that the area could eventually be turned into walking trails, tobogganing hills or a ski hill.
No matter what solution is eventually used, the process of planning for landfill decommissioning is one that requires engineering’s highest qualities of risk management and long-term planning.
Source:
https://www.apegs.ca/e-edge/Archive/Edge174/trash.html
