Improving the efficiency and sustainability of Saskatoon’s drinking water supply

Since 1906, the City of Saskatoon has provided residents and businesses with drinking water from its Avenue H Water Treatment Plant. The facility is a conventional surface water treatment plant, drawing water from the South Saskatchewan River and providing coagulation, filtration, and disinfection treatment before distributing potable drinking water to the city and the surrounding area.

Since its construction, the plant has undergone numerous upgrades and expansions. In 2015, the City and Associated Engineering completed design and construction of the Avenue H Reservoir, ultraviolet disinfection, and high lift pump station. The project involved a temporary solution for transferring filtered water from the existing filter clearwells to the new facility, including modifications to the former high lift pumps.

The City recognized that a sustainable long-term transfer pumping plan was required for improved operational reliability and energy efficiency. Major electrical upgrades were needed at the plant to replace an aging 4160V/600V system and improve redundancy. In 2017, the City engaged Associated as the prime consultant to deliver preliminary studies and long-term plans; conceptual, preliminary, and detailed design; construction administration; resident engineering; and commissioning services for the project. The project is nearing completion.

The project includes design and construction of a new 450 million litres per day capacity transfer pumping station and electrical system upgrades with a new medium voltage electrical room, a low voltage electrical room, and two new 2-megawatt generators to match the existing generators at the plant. Co-Project Manager, Scott Miller, says, "The generators are designed as a 'pooled' system, working interchangeably to provide back-up power."

Co-Project Manager and Process Mechanical Lead, Eric Gaudet, explains, "Several piping tie-ins were required to connect the plant’s existing filter clearwells with an underground piping network to convey water by gravity to each of the new transfer pumping forebays." From the transfer pumping station, two 1200 millimetre steel pressurized pipelines supply the existing Avenue H high lift pump station. The structural design included a 10 metre deep pump station substructure complete with two isolated pump wells to allow for fully redundant operation. The facility superstructure includes the new electrical rooms, generator and pump room, and rooftop mechanical and electrical equipment.

"Due to the complexities of tying in to the existing water treatment plant facilities, the electrical and pumping systems were designed to allow closed system commissioning through a detailed functional testing plan while avoiding impact to the existing water treatment plant operation."

Construction Manager, Josh Yohnke, says, "Several construction challenges were encountered when building the new facility within the confines of the existing plant site, involving both demolition, replacement, and tie-ins to existing infrastructure. Working in a century-old facility, there are many "unknowns". We uncovered abandoned, below-ground structures and pipelines, and contaminated soils from an early 1900’s electrical power plant."

The new transfer pumping station is designed for energy efficiency and long-term sustainability.

"It follows current guidelines and recommendations from the Hydraulic Institute with optimal pump selection, where the pumps' best efficiency points correspond closely with the most frequent flow rate analyzed from historic data. This new system has resulted in significant and noticeable energy cost reduction and reliability for the City."

Climate change adaptation was considered in the design of the HVAC systems, including free cooling for the low voltage electrical room with allowances for higher air flows, if required, for increased cooling days in the future. As well, the mechanical cooling system for the medium voltage electrical room was designed for projected increases in temperatures and cooling demands.

Our key personnel on the project include Scott Miller, Eric Gaudet, Josh Yohnke, Bob Hawboldt, Jared Suwala, Louis DeLange, Brody Masserey, Ashley Hodgson, Geoff Sarazin, Jason St. Germain, David Sorenson, Peter Hooge, Risto Protic, and Doug Olson.