A clean-water plant upgrade in Ontario is setting a new standard for sustainable design and construction. With modularity and a focus on complete sustainability, the Grand Bend Area Wastewater Treatment Facility has earned the Platinum Award — the highest honor — from the Institute for Sustainable Infrastructure (ISI).

Grand Bend is a small regional plant built in 1980 under the co-ownership of Lambton Shores and South Huron and operated by CH2M HILL. It needed to upgrade its capacity and its treatment process to serve a tourist area on Lake Huron in southern Ontario, just northeast of Detroit, Michigan.

The old facultative lagoon system, rated at 340,000 gpd, was updated to an extended aeration biological nutrient removal system with advanced tertiary filtration and a 656,000 gpd design capacity.

Affordable cost

The project was designed by Stantec after an original plan by another company was rejected in 2011 for its cost of $23 million Canadian (about $18.5 million U.S.), says Brent Kittmer, director of community services for Lambton Shores. Approved in 2014, the Stantec design came in at under $15 million Canadian ($12.1 million U.S.), two-thirds covered by grants from the provincial and Canadian governments.

ISI was founded by the American Council of Engineering Companies, the American Public Works Association, and the American Society of Civil Engineers. Working with the Zofnass Program for Sustainable Infrastructure at the Harvard University Graduate School of Design, ISI developed the Envision rating system to measure infrastructure projects based on environmental, economic and community benefits.

The Zofnass Program plans to create a business case study about the Grand Bend plant, the first ISI Envision-verified project in Canada and the first wastewater facility designed to Envision standards in North America. “Stantec proposed to design it using the Envision framework with intent to find true sustainability in the infrastructure and to reduce the cost,” says Kittmer. The plant will be in operation in early 2016.

Compact space

Despite nearly doubling its capacity, the new plant uses the same footprint as the old one. The administration and process building is a pre-engineered modular metal structure supplied by Nucor and built in what was one of the four original lagoons. It can be easily expanded in three directions.

“The building comes in prepackaged sets with steel columns, and bolts together,” says Kittmer. “We reduced the amount of concrete by more than $3 million.” The only concrete was for the building pad, two bioreactors, and the UV disinfection system.

The process equipment uses final effluent rather than potable water and is modular for easy expansion. Instead of deep sand filters, the plant uses a screen filter (Nova Filtration Technologies) for combined screening and grit removal. “When it comes time to expand, we can just unbolt it and put in a larger model,” Kittmer says.

The plant uses headworks equipment from Huber Technology, KSB pumps, and Aerzen blowers. Calgon Carbon Corporation provided the UV disinfection system and the activated carbon filters for odor control. The system is highly automated with a SCADA system integrated by Summa Engineering with Wonderware software (Schneider Electric, Invensys) and Rockwell Automation hardware. The only full-time employees are an operator and an administration person.

The automation makes the biological process highly flexible and scalable. “Being a tourist area, we see significantly lower flows in winter, so we can mothball one of the bioreactors,” says Kittmer. “In summer, when we have high flows, the inlet piping can divert peak flows to the remaining three lagoons.”

The use of the lagoons for flow equalization allowed the new plant to be built with far less capacity than first proposed. The plan rejected in 2011 would have quadrupled the original capacity.

The design meets the requirements of the Ontario Adaptation Strategy and Action Plan by preparing the plant for growth of the service area and for potentially more frequent and severe extreme rainfall events that could result from global climate change.

Natural approach

Using a lagoon for the new building and equipment required a large amount of fill to raise the elevation to ground level. “We took the dirt from the site, which created a large hole next to the plant,” says Kittmer. “Rather than import fill, we created a wetland that will be open to the public and will have walking trails.”

A tall-grass prairie surrounds the wetland. Both feature native plants, restoring habitat critical to threatened species including the monarch butterfly, snapping turtle, and bobolink (a small blackbird). Vegetation will be fertilized with biosolids from the lagoons.

After treatment to required levels, plant effluent will discharge to the wetland, which drains through a gravity outfall into a creek that feeds the Au Sable River a few miles from where it empties into Lake Huron, near a popular beach.

“It’s not an active part of the treatment process, but it will show how well a pond like this can polish effluent,” says Kittmer. “We plan to leverage that into a partnership with post-secondary schools in the area. Western University (London, Ontario) is interested in doing advanced water-quality research. We’ll have a good handle on what goes into the pond, and the intent would be to test the discharge from the pond to see if there has been any kind of improvement. It will be a neat learning process.”

Community effort

The Envision rating involves community involvement. The project team worked with conservation groups, volunteers and municipal staff to develop a plan that supports the elimination of invasive species.

All plantings in the wetlands will be coordinated through the local watershed management office of Conservation Ontario and local volunteer groups. “They will also engage the local elementary schools to help with the actual plantings and have school children come out to learn about sewage treatment and the wetlands,” says Kittmer.

The upgrade of the Grand Bend facility took years of discussion, dating back to the mid-1990s. Development of the master plan began in 2004. Kittmer says it has been worth the effort: “As people see the recognition the plant has received, I think we all agree that we have an excellent engineering firm and an excellent facility that definitely meets our needs.”

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Sustainability measures

The Envision rating system from the Institute for Sustainable Infrastructure includes 60 sustainability criteria in five sections: quality of life, leadership, resource allocation, natural world, and climate and risk. The criteria are scored on a 5-point scale by trained evaluators. To achieve a Platinum Award, a project must score 50 points:

• Improved — Performance that is above conventional (1 point)
• Enhanced — Sustainable performance that adheres to Envision principles (2 points)
• Superior — Sustainable performance that is noteworthy (3 points)
• Conserving — Performance that has achieved essentially zero impact (4 points)
• Restorative — Performance that restores natural or social systems (5 points)