Building Plan Changes Throw a Wrench into Nova Scotia Project

A last-minute bump in the size, scope and wastewater treatment needs challenge the designer and installers of a Canadian travel center

Building Plan Changes Throw a Wrench into Nova Scotia Project

 The Trans-Canada Highway, background, limited what could be done on the Bayside Travel Centre site in Afton Station, Nova Scotia. The shed holds control panels and blowers for the system — its Tuf-Tite lids are visible at middle right. (Photos courtesy Anua and Hatch Ltd.)

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For a long time, the small triangular property near Afton Station in northeastern Nova Scotia couldn’t be developed. The Trans-Canada Highway runs across this community land of the tribal Paqtnkek Mi’kmaw Nation, and the controlled-access highway divided the southern triangular parcel from the large northern property where the Paqtnkek Mi’kmaw have a health center and other buildings.

Then, in 2018, the Nova Scotia Department of Transportation and Infrastructure built a new interchange that included a bridge over the highway to connect the north and south community lands, says Matt Delorme, a professional engineer with Hatch Ltd. in Halifax. As its first economic development effort on the newly available southern parcel, the Paqtnkek Mi’kmaw built a travel center with two restaurants and plenty of room for trucks and other vehicles. Delorme designed the wastewater system, which had to be done in March 2020.

The system

Wastewater from the bathrooms and the restaurants exits the building in 8-inch pipes. Because of the BOD in restaurant wastewater, the two streams are initially separate. 

Wastewater from the bathrooms flows into a 3,500-gallon concrete settling tank. Tanks, plus TUF-TITE lids and risers, came from Brookfield Concrete in Brookfield, Nova Scotia. 

Restaurant wastewater flows through a Proceptor SV 3000 oil-grease separator from Zurn Industries, and then makes a 90-degree turn to join the wastewater stream flowing into the primary settling tank. 

Next, wastewater flows into a 4,500-gallon equalization tank with two pumps from EBARA Corp. that dose a pair of 2,000-gallon tanks connected in parallel as aeration chambers. Each aeration chamber contains three PuraACE high-strength pretreatment pods from Anua. 

Flows recombine and move by gravity to a 2,000-gallon clarifier tank. Sludge is continually pumped from the clarifier and returned to the upstream primary settling tanks for additional treatment. 

That’s what is neat about this system, Delorme says: It’s like a municipal wastewater treatment plant scaled down. 

From the clarifier, effluent moves to a pair of 3,000-gallon dosing tanks. The first has two STEP 50 pumps from Sta-Rite (Pentair). Pumps alternately dose five of the 10 Anua AeroCell IM1530 pods in the system. The second dosing tank receives 80% of pod effluent for further treatment. The remaining 20% of effluent discharges through an Anua Puralinity passive pH buffer basin to a drainfield made with about 490 feet of 4-inch perforated pipe. Piping is divided into five laterals bedded on crushed stone. 

Technicians used a pair of Cat excavators, a 320 and 315, to do the job along with a Cat 930 loader and a pair of Cat 300 rock trucks, says Brent Boyle, project manager for installer Francis J. Boyle Construction of Afton Station.

The job went smoothly given that construction was done in January and February, he says. 

“We were cold. We were minus 25 Celsius,” Boyle says. That’s minus 13 Fahrenheit. Insulated tarps and heaters kept the job moving, Boyle says. “We’re used to that kind of weather.” 


Waste strength was a concern from the beginning, Delorme says. During the design phase, restaurant tenants hadn’t been selected, so it was unclear just how strong influent would be.

The two restaurants that eventually contracted for space were a fried chicken shop named Mary Brown’s Chicken, and a branch of Tim Hortons, a chain of stores selling coffee, tea, baked goods and other quick-serve foods.

“Right from the outset we knew Tim Hortons was potentially on board, and they have a substantial engineering department, so we were looking at their typical waste streams when considering the system. They also have a decent grease separator and food trap within their facility, as does the other restaurant,” Delorme says. 

But tenants can change as time passes, and sometimes people don’t maintain systems well, he says. That’s why the design splits the waste stream and uses the Proceptor separator, which can be maintained independently by the travel center owner.

Another concern was the chemicals used in restaurant dishwashing and cleaning. Delorme wanted to minimize “quats,” the quaternary ammonium compounds that can be toxic to microbes in wastewater systems. That will be addressed with tests to measure quat concentration and, if needed, conversations with the restaurants about their processes.  

Plans change

“Our original plan was to go with a conventional onsite system,” Delorme says. 

It would have used a large sand filter for final treatment. Then the project changed. Initially the travel center was to have been 9,500 square feet with a single drive-thru restaurant and a large lot for trucks and other vehicles. As design continued, the building expanded to 16,000 square feet, and a second drive-thru restaurant was added. A wetland on the north side of the property, and the parcel’s triangular shape, limited siting options for the sand filter.

“With the building changes, we ended up halfway through the project saying, ‘No, no, we don’t have room anymore for our initial plan,’” he says. 

As the projected cost of the system escalated, he says, engineers thought about directionally drilling under the Trans-Canada Highway and connecting to the municipal wastewater system serving the clinic and other buildings. But that plant was sized for future needs and had no spare capacity.

That led to the current system. Because treatment is largely handled with enclosed components, those could be sited on sloping parts of the site, Delorme says. And because effluent is so clean, he says, there is no biomat formation in the drainfield, infiltration rates are higher and the drainfield can be smaller.

“Our target is 30 mg/L on the BOD, and my last test said it was running at 7,” he says. Influent BOD is between 250 and 500 mg/L, but the system is designed to treat higher flow rates and BODs expected when the second restaurant comes online soon.

At one point, the design team worried that the radical shift in treatment technology would delay the spring opening of the business, Delorme says. But local Anua distributor Sansom Equipment, plus Anua itself, Brookfield Concrete, and installer Brent Boyle — went above and beyond, Delorme says. 

“Especially the Sansom guys — I was talking to them before Christmas break, and we were putting designs together over Christmas break to meet manufacturing deadlines,” he says.

From government approval of the revised system to commissioning of the installed system was three months, he says. “From past projects, I literally thought this was impossible to meet.”

For the Bayside Travel Centre, this team delivered the impossible. 


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