York-Durham Sewage System

Taking the full lifecycle approach

The York Durham Sewage System (YDSS) is a project that was literally decades in the making. The idea for the centralized sewage treatment system dates back to 1965, when the Province of Ontario decided that no additional sewage treatment plants could be built on the Humber, Don and Rouge Rivers. At the time, there were 11 community plants that distributed wastewater effluent into small streams (destined for Lake Ontario). As both regions continued to grow, however, the effluent was simply too much for the streams to handle.
First constructed in the late 1970s and early 1980s, the state-of-the-art sewage system converges at the jointly operated Duffin Creek Water Pollution Control Plant (WPCP) located in Pickering. The existing facility treats sewage flows collected and conveyed from both regions, connecting municipal sewers through a network of more than 3300 kilometres of sewer pipe.

As with all infrastructure, long periods of time demand maintenance, improvements and, at times, expansions. In the case of YDSS, all of the above is needed to keep things running smoothly, especially given the projected population growth (forecasted to grow from 930,000 in 2006 to 1,500,000 by 2031). Because all municipalities of the GTA are highly sensitive to federal immigration rates, the area remains attractive to both new and native Canadians. Presently, The Regional Municipality of York is working on new projects that will expand the YDSS to accommodate the influx of people.

‘A complex system’

CBJ had the opportunity to interview Daniel Kostopoulos, Director of Capital Planning and Delivery for Environmental Services at The Regional Municipality of York, to discuss the upgrades. Right away, Kostopoulos describes the undertaking as a significant project, financially and technically. “The York Durham Sewage System is a very big and complex system,” he says. “It is a living, growing entity that continues to be expanded to provide service to meet the growing needs of York and Durham Regions. There are a number of projects involved.”

“One of the major projects, of course, is the expansion of the Duffin Creek WPCP itself,” Kostopoulos continues. “It’s a $585 million project that will increase capacity, so the plant can process more sewage. Another major investment is the Southeast Collector Trunk Sewer Project (SEC), a 15-kilometre tunnel trunk sewer that will convey sewage toward the plant—from Markham to Pickering.” The SEC project totals $546 million, and will cross through residential, commercial, industrial, and agricultural areas.

Together, the two projects are over a billion dollars in capital costs and that price doesn’t factor in the ongoing expansions in conveyance to service growing communities within the region for the past decade.
Commitment to the environment

On a social level, the YDSS doesn’t only factor in the citizens it serves, but also considers the surrounding environment it affects. “The system continues to serve as one of the best, one of the most environmentally friendly systems in the entire Great Lakes Basin,” affirms Kostopoulos. “That has been a focus for both regions: maintaining that leadership in sanitary sewage servicing.”
Putting words into action, The Regional Municipality of York has incorporated sustainability into all of the projects it has delivered throughout the last 10 years. Unlike many of the GTA’s sewage treatment plants, and in fact, sewage treatment plants around the world, the Duffin Creek WPCP is not designed to allow untreated sewage to overflow directly into Lake Ontario. In addition, York Region does not have any “combined sewer systems” that convey both stormwater and wastewater flows during wet weather events—which can result in overloaded treatment plants and untreated or partially treated sewage discharged into lakes and rivers.

Outside of the plant, The Regional Municipality of York is involved in projects within its community. “We are working closely with the Toronto and Region Conservation Authority,” explains Kostopoulos. “We have added a lot of enhancements through a biodiversity plan—everything from planting trees and creating habitats adjacent to the marsh, to dividing the plant lands from the natural lands and creating a wildlife corridor for migration. We’re also adding recreational enhancements like walking trails and lookout areas near Lake Ontario.”
“As we expand our system, we continue to learn from our experiences and up the ante, in terms of leaving a positive legacy as we go,” Kostopoulos continues. “We always look to improve in how we continue and what we leave behind. We follow the best practices in the industry, but go over and above that.

Continued commitment

It is the intention of YDSS to stay on track in meeting the needs of both regions and to accommodate their growth, providing sustainable and responsible delivery, maintenance and operation of the infrastructure.
“We are looking at our work from a full lifecycle approach, not just the construction side of things. The underlying theme is striving to surpass all legislated requirements. We are going well beyond the minimum requirements of environmental assessments and all the regulatory requirements of the agencies. We are certainly aiming much higher and raising the bar to ensure we leave a positive legacy for our future users and communities,” says Kostopoulos. “This is infrastructure that will be in the ground for the next century, so we need to look at it in that perspective. When you look at all the projects, it’s a serious investment that York Region and Durham Region are making into their futures.”