6 minute read
A new water pump station for Calgary
Flow magazine found out how technology from the specialist pump manufacturer, KSB, was used in the development of a new pump station in the Canadian city of Calgary, and the refit of another pump station in the same area.
Calgary is one of Canada’s fastest growing metropolitan cities and is the major urban centre for the southern half of the province of Alberta. Calgary is located in the foothills of the Canadian Rocky Mountains, at the confluence of the Bow and Elbow Rivers. Originally founded around agriculture, the city is now the heart of Canada’s energy sector, with much of the current economy driven by oil and gas production.
With an expanding population of over three million and the continued diversification of industry and commerce, the ever-growing demand from Calgarians for potable water has to be met. To satisfy both current and future demands for safe and reliable drinking water, The City of Calgary has recently embarked on a $35M CAD project to replace the most critical water pump station in the city. The existing Shaganappi Pump Station, originally constructed in 1978, supplies drinking water to over 200,000 residents of Calgary and surrounding communities. Shaganappi Pump Station is the area’s largest pump station. It is a vital component of the city’s water transmission network, which consists of 41 pump stations and 23 storage reservoirs connected by over 4,500km of underground piping. This large number of pump stations and reservoirs is required due to the region’s varying and often rugged topography, which divides the city into many smaller water pressure zones based on elevation.
THE PROJECT
The City of Calgary owns and operates two water treatment plants: the Bearspaw Water Treatment Plant and the Glenmore Quarter 3 2021 Water Treatment Plant. These state-of-the-art treatment facilities draw their source water from the Bow River and the Elbow River, respectively. Both treatment plants combined can produce a total of 950ML of clean drinking water per day. Treated water is stored on site at the treatment plants before being pumped into the transmission network for distribution throughout the city. The Bearspaw plant, located in the city’s northwest quadrant, pumps water into three separate underground feeder mains. One of these feeder mains is the 1950mm diameter South Feeder, Calgary’s largest and most critical feeder main. Shaganappi Pump Station draws water directly from the South Feeder and then effectively splits the flow, adds hydraulic energy via pumping and redirects the water to north and south Calgary.
The existing Shaganappi Pump Station is over 40 years old and is past its useful life expectancy. Many of the mechanical and electrical components within the existing pump station are now obsolete, creating operational and maintenance challenges. Given the critical nature of this pump station and the extensive upgrades required to ensure efficiency and reliability, the decision was made to replace the existing pump station.
The new Shaganappi Pump Station, which is currently under construction, will be located approximately 200m west of the existing facility. This will allow the city to reuse much of the existing underground infrastructure, including the original piping connection to the 1950mm diameter South Feeder. This location was chosen to reduce construction costs, minimise disruption of the water system and surrounding communities and facilitate a smooth transition between the existing and new facilities.
Calgary’s water pump stations are considered critical infrastructure and are designed with redundancy to allow them to continue to operate in an emergency. The existing Shaganappi Pump Station utilises natural gas engines to drive backup pumps in the event of a power outage. The new pump station will utilise a 944kW natural gas generator capable of starting and running one or more pumps in the event of a utility outage. The use of natural gas generators in new pump station installations offers an efficient, flexible and safe solution that meets the city’s critical infrastructure requirements.
THE CHALLENGE
Establishing a strong working relationship between KSB Canada and The City of Calgary has been advantageous to both parties. The city issued a Request for Proposal (RFP) in late 2017, in search of a vendor to supply pumps and drivers for existing and new water pump stations. KSB Canada was the successful proponent in this stringent RFP process, which saw the contract awarded in May 2018. The contract included the supply of pumps and drivers for the new Shaganappi Pump Station project, along with other projects such as the Palliser Drive Pump Station retrofit. “The Palliser Drive project enabled us to demonstrate to The City of Calgary the capabilities and benefits of our Omega pumps”, reported Pasha Barazandeh, Regional Sales Manager at KSB Canada. “For this project, we supplied two electrically driven pumps and one natural gas engine driven pump to meet a pumping requirement of up to 60ML/d. The city was pleased with this installation, and 12 months on, it continues to run well.”
While the Palliser Drive Pump Station project was underway, details for the new Shaganappi Pump Station were being finalised, and the pump supply was put into motion. The requirements for Shaganappi involved the supply of three large KSB RDLO 600-600 pumps rated at 80ML/d and three smaller Omega 300-560 pumps rated at 30ML/d to give a station design capacity of 220ML/d. This allows for a total capacity of over 300ML/d with all six pumps in operation. However, such a situation is not anticipated to happen. “For 80% of the time, only one of each pump type might be working at the same time, servicing two different pressure zones for the water supply system,” explained Pasha.
One of the key challenges for KSB Canada was the size of the natural gas generator at Shaganappi Pump Station. “The pumps’ configuration and power requirement had to be modified to meet and exceed the duty condition. To meet this condition, we needed to modify the pump hydraulics to maximise efficiency for the most frequent operating conditions,” continued Pasha. “This led to delivering the lowest lifecycle costs and optimum operating reliability.”
The requirements for Shaganappi involved the supply of three large RDLO 600-600 pumps rated at 80ML/d and three smaller Omega 300-560 pumps rated at 30ML/d. The pumps’ configuration and power requirement had to be modified to meet and exceed the duty condition.
The City of Calgary specifications stated that they required betweenbearings, axially split case centrifugal pumps. Other specific requirements included suction and discharge nozzles provided with integrally cast flanges to ANSI/ASME B16.1, the impeller trim diameter to be no more than 98% of the full size and removable wearing rings on the impeller and casing. There were also several specific material requirements to satisfy national and international standards relevant to the handling of potable water.
THE SOLUTION
Proven in many water applications around the globe, the RDLO and Omega pumps were identified as being more than capable of meeting the customer’s specific demands. KSB’s axially split, single volute casing RDLO and Omega pumps feature a doubleentry radial impeller and are well suited to the requirement of the water pumping stations. They transport fluids with a minimum of flow resistance, thus lowering the energy and life cycle costs of the systems in which they are installed. CFD optimised hydraulic systems deliver the best duty point and give operating efficiency levels above 86%. The double entry impeller balances the axial forces, so the load on the maintenance-free bearings is minimal. The combination of solid bearing brackets, a short and rigid shaft and preloaded bearings guarantees low vibration and extended operating life for the bearings, seals and coupling. Being axially split case pumps simplifies maintenance procedures, enabling ready access to all parts for thorough inspection. The drive may be positioned on both the left and right of the pump without additional parts or modifications to the casing being necessary.
