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Sep 14, 2026, 9:53:43 AM

Reducing Repeat Blockages at a Network Wastewater Pump Station

Reducing Wastewater Pump Blockages | Prime Fluid Management

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“Over four months, what could have been 16 to 32 callouts was reduced to only two.”

Ricardo Holt - Sales Engineer, Prime Fluid Management

Weekly pump blockages had become routine at a Bay of Plenty wastewater pump station – sometimes occurring twice in the same week.

Each overload alarm triggered another contractor callout, another pump lift and another manual cleanout before the pump could return to service.

The pump met the duty point – but its hydraulics weren’t coping with the wastewater.

The client

A Bay of Plenty local authority

The project

The network pump station receives raw sewage from a residential catchment before pumping it onward to a larger transmission station.

With the existing pump repeatedly triggering overload alarms, the council agreed to trial a Hidrostal BN Compact pump to see whether a different hydraulic design could improve reliability and reduce maintenance intervention.

“It was one of many pump stations across the network, but recurring blockages meant the pump was needing attention as often as once or twice a week.”

Ricardo Holt

The challenge

The issue wasn’t flow or head. Fibrous material in the raw sewage was likely restricting the impeller – increasing motor current until the pump tripped on overload.

Each blockage added maintenance costs and increased health and safety risk from wastewater exposure.

“Every time the pump overloaded, it put added stress on the electric motor.”

Ricardo Holt

Dealing with recurring wastewater pump blockages? Talk to Prime about matching the pump hydraulics to the material.

The solution

Prime proposed trialling a Hidrostal wastewater pump to see whether different hydraulics could reduce ragging and overloads while still meeting the required duty point.

A Hidrostal BN Compact submersible pump with a screw centrifugal impeller was selected to allow coarse and fibrous material to pass through more freely.

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Hidrostal's screw centrifugal impeller

“Hidrostal’s screw impeller design allows solids to pass through more freely than most pumps of this size.”

Ricardo Holt

Pump selection considered the required flow and head, wastewater conditions, upstream contributors, wet well layout, and compatibility with the existing guide rails and discharge pedestal.

An adapter allowed the pump to use the existing guide rails and connect to the installed pedestal – avoiding a larger rebuild of the wet well.

Prime worked with the council’s maintenance contractor during installation, provided technical and electrical input, and reviewed performance throughout the trial.

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The Hidrostal BN Compact submersible pump installed

Find out how Prime keeps flow moving at wastewater pump stations.

The outcome

Over the monitoring period, the trial delivered a substantial reduction in overload-related maintenance.

The result gave the council confidence to purchase the pump and retain it permanently at the station. Prime has since discussed a similar approach at another pump station experiencing recurring issues within the same network.

Get in touch with Prime to discuss network pump station issues in your region.

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