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Water supply in the Netherlands: Waternet pumping station in Utrecht

Rejuvenation of two ageing pumping stations supplying raw drinking water in Utrecht (direction of Amsterdam)

Waternet, the water utility for the Utrecht region, ensures that drinking water plants and industries in the Amsterdam region are reliably supplied with raw drinking water. Two of their pumping stations were starting to show their age and needed to be modernised. The goals: more efficiency and less work for staff. Exactly the right challenge to put to the experts at KSB!

The project: Modernisation of two pumping stations for supplying raw drinking water

Although pumping stations are generally designed for a long service life, eventually the time comes when they need to be completely modernised. The pumping stations operated by the Waternet Water company had reached this point a few years ago. Their energy consumption was no longer up to current standards, the noise emissions were too high, vibrations and cavitation were causing problems in the system, and the amount of work required for maintenance also needed to be significantly reduced.

Modernising the pumping stations involved dismantling a total of 18 old pumps and installing eight new RDLO 500-685 A GB pumps with 1MW 6kV motors – plus renewing all associated piping, the ventilation system, the electrical installations, the VSD (variable speed systems) and the control cabinets.

At the end of the tendering process, only two bidders remained who were able to meet the required specifications. However, KSB was also able to warrant more cost-effective total life cycle costs over a planned calculation period of three decades and was therefore awarded the contract.

The customer: Drinking water supplier Waternet Amsterdam in the Netherlands

The water supplier Waternet serves the regional public water authority Amstel, Gooi en Vecht and the municipality of Amsterdam. The company ensures that citizens are reliably supplied with a sufficient amount of fresh drinking water. As the supply area is below sea level, the company also has to make sure that the 1.3 million residents in the catchment area are protected by dikes.

Pumping station of water supplier Waternet equipped with 4 RDLO water pumps

Pumping station of water supplier Waternet equipped with 4 RDLO water pumps

The challenge: Tight timing, lots of people involved – and the coronavirus pandemic

The project entailed several different types of challenges and presented the project team with a number of hurdles. First of all, the planning was divided into four very tightly timed phases, further complicated by the fact that no major work could be carried out on the system during the summer flood season. On top of this, many of the planning and implementation measures took place precisely during the time of the global pandemic.

However, the main challenges resulted from the design constraints in the existing building: 

  • The correct positioning of the inlet nozzles in the underfloor intake chamber,
  • Ensuring an even, vortex-free flow in each suction line,
  • Construction of vibration-free pump foundations,
  • Cooling the variable speed system with outside air,
  • Sophisticated control equipment

A wide variety of disciplines were involved in the project which were dependent on each other, but this was handled successfully thanks to effective communication and mutual understanding on all sides.

Construction began in November 2018. However, due to various delays and the exceptional circumstances, it was not possible for the handover to take place until October 2021.

KSB RDLO volute casing pump

Single-stage, axially split RDLO volute casing pump for horizontal installation on vibration-free concrete foundation

The solution: Efficient cooperation between all project participants

The hydraulic engineering design was provided by KSB Nederland in cooperation with specialists from the Global Sales team at KSB Halle, while the engineering for the pump foundations, pipe diameters and pipe supports was carried out in cooperation with HAL-Engineering in Halle. KSB also checked the electrical installations with a professional consultant and provided the missing manpower.

The RDLO 500-685 water pumps were first tested at the Halle test facility to ISO9906 class 1U and then with complete drive train (motor, variable speed system, transformer and coupling). The following components were subsequently installed in the Netherlands. 

Thanks to the high efficiency and performance of the installed RDLO pumps and the drive train components, the multi-million euro investment will pay for itself within a very short time. The objectives were achieved and the customer was highly satisfied with the solutions supplied by KSB. 

Figures| Data| Facts


2 pumping stations

End user:

Waternet Amsterdam, Netherlands

KSB type series used in this project:

8 x RDLO 500-685 A GB with 1MW 6kV motors


2019 and 2020 ( in four phases) hand over in 2021

Used products:



Single-stage axially split volute casing pump for horizontal or vertical installation, with double-entry radial impeller, mating flanges to DIN, EN or ASME.