Despite many challenges, Unit Precast installs an on-site wastewater treatment plant in the dead of winter for a private golf course.
By Shari Held
During the summer months, celebrities flock to the Township of Muskoka Lakes, Ontario, and scenic “Cottage Country.” The area is known for its upscale cottages, resorts and “Millionaire’s Row” as well as picturesque lakes, acres of lush green forests.
According to Golf Inc. magazine, Ontario is home to more than a third of Canada’s golf courses, and golf is considered by many Canada’s No. 1 recreational sport.
Located in the township’s municipal seat of Port Carling since August 1922, Muskoka Lakes Golf and Country Club has been offering its members a place to play tennis and golf, enjoy water sports and dine in a beautiful, tranquil setting. The private club features a waterfront clubhouse and a par 70, Stanley Thompson-designed 18-hole golf course.
In 2018, it was evident the club’s septic system was no longer adequate for its current needs, much less its future needs.
“The existing septic tanks and beds were both undersized and appeared to be nearing the end of their useful life, as evidenced by the build-up of biomass in the active beds,” said Mateusz Lewandowski, former engineer for water infrastructure for southern Ontario-based Cole Engineering Group, now part of IBI Group.
In addition, the club planned to expand the clubhouse and increase its services. It was the perfect time to replace the septic system. From the beginning, the project was on a fast track. It was designed in 2018, approved late 2019 and completed in 2020.
“Projects don’t often happen that quickly,” said Scott Robinson, managing director for Unit Precast, based in Breslau, Ontario. Unit Precast fabricated the new precast concrete wastewater treatment system and installed the technical equipment for the project.
THE WASTEWATER SYSTEM DESIGN
When it comes to on-site or decentralized wastewater treatment systems, several options exist, such as activated sludge, trickling filter and moving bed biofilm reactor (MBBR) process.
RH2O North America, a designer and manufacturer of decentralized wastewater treatment systems located in Breslau, Ontario, designed an MBBR process for the Muskoka Lakes Golf and Country Club. It is a relatively new process that originated in Norway. At its core is a biofilm carrier media that optimizes biofilm growth to treat the wastewater. The media is self-cleaning, does not clog and is designed to never need replacing.
RH2O has manufactured MBBR wastewater treatment systems for commercial on-site plants since 2006 and has tailored the technology for optimal performance in the Canadian climate.
The MBBR biological process combines the benefits of the activated sludge and attached growth wastewater treatment processes. It can remove carbon and ammonia in a small footprint, which was important since space was tight for this project. The Muskoka Lakes Golf and Country Club also hosts private parties and weddings during the period between the peak season and the offseason. A typical septic bed is not designed to meet the demands of the club’s kitchen during those events.
“The MBBR system would allow us to meet the Ministry of Environment, Conservation and Parks’ effluent criteria, which is why it was selected,” Lewandowski said.
The club’s wastewater treatment system was custom designed for 32,000 liters of wastewater per day to serve the clubhouse, staff quarters and pro shop. The system was designed to treat higher-than-domestic-strength wastewater with influent up to 500 mg/L BOD5 (biological oxygen demand), 400 mg/L of TSS (total suspended solids), 100 mg/L TKN (total Kjeldahl nitrogen) and 10 mg/L of TP (total phosphorus).
The system also features a dissolved oxygen (DO) sensor to automatically adjust the aeration system and reduce energy costs. It has a programmable logic controller (PLC) control panel, which allows the settings on the wastewater system to be changed remotely. The mechanicals are housed in an exposed aggregate precast control building.
The wastewater treatment system consists of eight precast tanks:
- 1 8,000 IG (imperial gallon) flow equalization tank with duplex and vortex sewage pumps.
- 1 8,000 IG sludge storage tank.
- 1 2,400 IG pretreatment or primary clarifier tank.
- 2 3,000 IG bioreactor tanks for the MBBR processes.
- 1 3,300 IG clarifier tank for intermediate clarification process.
- 1 3,000 IG final clarifier tank.
- 1 3,000 IG final pump tank that pumps the effluent wastewater to multiple disposal beds.
PRECAST: A GREAT FIT
With an MBBR system, the tanks can be made of precast concrete, fiberglass or polyethylene. The existing septic tanks were precast, and the club liked the way they had performed, but precast was the clear choice for this project for several other reasons, too.
“In this case, we had to fit the tanks in a very small footprint,” Robinson said. “We could custom design the precast, whereas with fiberglass tanks we wouldn’t necessarily have been able to fit them in this tight area.”
Precast also proved to be a better solution because the tanks were placed around a steep slope. They had to be structurally sound. Precast not only is strong and durable but also more cost-effective
than other materials.
Ultimately, it was the project’s short time frame that made precast the most viable option.
“Precast tanks were selected because the golf course operates seasonally, and we could only complete the replacement of the septic system in the winter months,” Lewandowski said. “The precast tanks provided a quick installation and ensured the quality of the buried tanks was not impacted by the weather conditions.”
A CHALLENGE-FREE FABRICATING PROCESS
Unit Precast manufactures CSA-B66-compliant precast concrete septic and holding tanks. CSA B66 requires a minimum concrete strength of 35 MPa, which is more than 5,000 psi.
“We make a self-consolidating concrete (SCC); that is typically more than double that value,” Robinson said.
Unit Precast was able to use its standard steel molds with custom modifications for lid placement and inlet and outlet access openings.
The tanks ranged from 12 tons to more than 20 tons. The two largest tanks were made in three sections, whereas the six smaller tanks were manufactured in two sections. In all, Unit Precast fabricated the 18 elements for the eight tanks in only four weeks.
“Normally, with projects like this, once they’re confirmed, we have around a six-to-10-week turnaround time,” Robinson said.
A CHALLENGING INSTALLATION
The tanks were transported 3 ½ hours away with Unit Precast’s crane delivery trucks and flatbed trailers. While the fabrication process was a breeze, the transportation process proved challenging. The winter weather made it difficult for the flatbed trucks to make it up the steep hill to the golf course.
Challenges began full force during the installation process, which started Dec. 16. One of the main challenges was the severe weather conditions. The frigid temperatures – at times, minus
30 Celsius – were brutal. That’s minus 22 Fahrenheit!
“It was not only extremely cold, but we got tons of snow while we were doing the installation,” Robinson said.
The sub-zero temperatures also were hard on the equipment and hydraulic lines. The butyl sealant had to be kept inside the trucks so it would stay warm enough to compress. Workers used torches to blow precipitation off of the tongue-and-groove connections prior to installation so the tanks would seal properly.
Almost as difficult were the space constraints. The wastewater treatment system is located on the fairway by the first green. On one side, the fairway is bordered by trees, and there is a steep hill to the left of the tree line. Ordinarily, the trees would be removed, but since the project was for a golf course, the trees had to be retained for both aesthetic and practical reasons.
“Golfers are all about picturesque scenery,” Robinson said. “If they’re teeing off on the first green and they see a sewage treatment plant, that’s not an option. Preserving the trees was important to keeping that view of the treatment system hidden.”
Great care was taken when accessing the job site, which also included a raised tee box. Sensitive construction measures were required to leave the golf course as pristine as possible.
Unit Precast used its HIAB knuckle boom cranes, which are attached to the company’s delivery trucks, for the installation. Trying to maneuver a stand-alone crane in the tight space would have been difficult and would potentially cause more damage to the job site.
Despite the challenges, all eight tanks were installed in only two days. During the remaining two days, Unit Precast installed the technical equipment including pumps and piping inside the tanks and in the mechanical building. The system was fully installed and ready for backfill by Dec. 20.
“It was a difficult project with tight access and unfavorable weather. I was on-site and proud of our team’s work,” Robinson said.
Once the wastewater treatment system was installed, the old disposal beds, which also run along the fairway of the first green, could be replaced and additional beds installed to handle the increase in wastewater flow.
A SATISFIED CUSTOMER
A year later, golfers at Muskoka Lakes Golf and Country Club cannot even tell that in winter 2020 the first green was the site of such a major project. The new MBBR wastewater treatment plant is working well, and the club is satisfied.
“We’ve been performing operation and maintenance on the system for over a year or so,” Robinson said. “Everything’s been meeting the performance requirements of the project.”
Shari Held is an Indianapolis-based freelance writer who has covered the construction industry for more than 10 years.
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