EXP’s Senior Director, Infrastructure Mark Langille and Mechanical Coordinator Bradley Legault recently presented at the 2022 Ontario Water Works Association’s Water Conference & Trade Show on a one-of-a-kind project – The District Municipality of Muskoka Fairyview Water Treatment Plant Upgrades Project. The presentation focused on a cost-effective solution to water treatment plant bypass design, a unique design and solution developed by the team to upgrade the Muskoka Fairyview Water Treatment Plant.
The Muskoka Fairyview Water Treatment Plant is an older facility and faced redundancy issues that did not allow pump chambers and clear wells to shut down for inspection and maintenance. EXP was commissioned to provide access to the chambers and clear wells for regulatory inspections and maintenance while still providing potable water to the Town of Huntsville. This solution designed by EXP included construction in two phases.
Phase 1 ‒ civil phase
Phase 1 of the solution was civil phase construction (2019-2020). EXP’s design consisted of a 720-meter, 600mm diameter serpentine pipe and was completed during the first phase. The pipe was designed to mimic the chlorine contact chamber and provide proper contact time to the water before distribution. It allowed the existing chlorine contact chamber to be isolated and shut down for a lengthy period of time. This pipe was buried behind the water plant and tied into the existing distribution system. It was designed to handle the maximum flows through the Fairyview Water Treatment Plant and provide a long-term solution.
Phase 2 ‒ mechanical phase
Phase 2 includes mechanical phase construction. Once chlorine contact time (the time required to disinfect the water at a specific concentration) was achieved, EXP provided alternate means to ensure water supply to the distribution system while maintaining the required pressure and flow. It allows the high-lift pumps to be taken off-line and for the high-lift pump well and chlorine contact time chamber to be drained and inspected. Since the backwash well is isolated from the other two chambers by a spill-over weir, the team proposed a solution to utilize the backwash pumps and supply water to the distribution via the backwash pumps in series with a booster pump system.
EXP’s innovative solution
While in phase 2, the team faced another critical challenge. The high flow rate and low head capacity of the backwash pumps hindered the head requirement to pump to distribution. That’s when the team came up with an innovative solution for designing a booster pump system.
“The booster pump system in series with the backwash pumps helped us achieve proper capacity levels and completely bypass the chlorine contact chamber and the high-lift well. We were able to save between 4-6 million dollars by constructing this system and remain under the budget approved by the district,” said Senior Director, Infrastructure Mark Langille.
EXP made the following upgrades to the plant during the project:
- The booster pump system operated for ten weeks and provided flows upward of 5500 m^3 per day during the summer of 2021.
- During construction, the chlorine contact chamber and high-lift were isolated and received a full inspection, maintenance and modifications.
- The opening that fed from the chlorine contact chamber to the high-lift was filled with a sluice gate, and a new spill-over weir was cut open.
- Filter effluent discharge was upgraded from one point of entry to three to allow for various operational scenarios (discharging directly to high-lift, to chlorine contact chamber or original backwash well).
- Upgraded HVAC and diesel generator within the water treatment plant.
During construction, the Fairyview Water Treatment Plant was fully operational and was compliant with all the Ministry of the Environment, Conservation and Parks regulations and requirements on the new system operation. The system has the capacity to deliver 400 m^3/hr (110 L/s)at the required total dynamic head while providing proper disinfection.