New Grundfos hydraulics reduce clogging problems and help build confidence into wastewater handling

When the Water Authority Vechtstromen in the Netherlands built a new wastewater pumping station, they installed the new S-tube® impeller into a SL pump, to ensure reliable operation.

Vechtstromen is a regional water authority in the East of the Netherlands. Within its water management area there are 23 midsize cities. The operations and maintenance department runs 106 pumping stations and 23 wastewater treatment plants. One old pump station had to be demolished and was replaced with the new one called ‘Erica’. 

The situation

Clogged wastewater pumps are very costly to utilities. Besides work required to clean the pumps, clogging often leads to unreliable operation in the wastewater network and even overflow to the environment. 

The pumps in the old station, from 1987, were at the end of their lifecycle. They clogged several times per month, and in weeks with heavy rain it could be several times per week, each time requiring dismantling and cleaning. A replacement of the pumping station was scheduled for 2018. The new pumps had to meet the following demands: free from clogging, and minimal life cycle cost for 25 years.

The operations team no longer wanted to throw money at old technology, so they turned to the Grundfos sales team in the Netherlands for a more reliable and permanent solution. 

The satisfied Operations Manager, Ivo ten Brinke (right), shows around the new pumping station.

The solution

The pumping station ‘Erica’ was the perfect place and time to introduce Grundfos new S-tube® impeller; a leading hydraulic technology ensuring high operational reliability and durability, a high wire-to-water efficiency and a high level of serviceability.


The Grundfos 18.5 kW SL pumps are wet installed in the pumping station.

The result

The new pumping station began operating in September 2020 and the results have been impressive. Since the installation of the new Grundfos pumps fitted with S-tube® impellers, there has so far been no clogging events at all and no need for any unscheduled service calls. This is very impressive compared to the three to four service interventions per week with the old pumps.

“So far, the SL pumps have run for around 1000 hours, and intervention has not been required,” says Ivo ten Brinke, Senior Process Operator, Vechtstromen. “We carry out a yearly inspection of our pumps, and if the pump with the new impeller continues to operate in this way, we are very interested to see the state of the wear parts at that time.”

The pumps are operated by variable speed drives.

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