Australian utilities fight battles against sewer clogs and the potential overflows that may result. The rise in the use of personal wipe products and their improper disposal has worsened the problem.

Operators and technicians often crawl into confined spaces or hoist pumps out of wet wells to wrestle with rag monsters.

KSB Australia is well aware of this issue and is leading a campaign to “Conquer the Clog”.

The newly developed free-flow impeller for wastewater pumps will be the trade fair highlight showcased by KSB Australia at this year’s OzWater in Sydney.

The F-max impeller incorporates different distances between its blades, arranged in groups with two small and two large distances.

The asymmetrical blade arrangement offers impressively wide free passages, ensuring that even larger, rigid solids pass easily and are reliably handled by the pump. The blades were designed to create a swirl in the hub area.

This swirling effect shifts fibers away from the impeller hub and transports them to the outside. Based on decades of experience in free-flow impeller design, KSB hydraulic experts employed the CFD method (Computational Fluid Dynamics) to gain detailed knowledge about the complex flow processes inside the pump via computer-aided simulations.

The new F-max impellers are achieving efficiencies previously only reached by single-channel impellers. Subsequent balancing is no longer required.

The radial forces and vibrations created by the new impeller are usually lower than those of single-channel impellers, so the service life of shaft seals and rolling element bearings is increased. Pumps with F-max impellers require only minimal maintenance.

When they rotate, free-flow impellers develop a strong swirl which keeps solids suspended in the pump casing and, with the inclined suction area, generates an additional flushing action. This significantly reduces the risk of clogging in the impeller’s centre caused by long fibers, in particular by wet wipes.

KSB Australia’s holistic approach to clogging

It starts with a good design – the pump and impeller must fit into design parameters. When properly executed, it all works together with minimal need for maintenance or downtime.

Station design

While the increasing use of wipes is a challenge, different systems handle the problem differently, and variable fluid content influences performance. Engineering and planning of wastewater facilities requires an understanding of the pumped wastewater composition for trouble-free performance and energy efficiency.


KSB offers highly specialised technologies to assist in the control and monitoring of the wastewater treatment process.

This includes process control systems to monitor and optimise pumps, valves, flow rates, and other critical information.

Solids separation

In all waste streams there are solid and liquid components. To “Conquer the Clog”, it’s best to first remove as many of the solid components as possible.


The heart of the hydraulic system is the pump and, more importantly, the impeller. The design and efficient operation of these critical components is essential for successful fluid flow. This is the systemic approach – all components must work together.

Impeller technologies

There are many types of impellers – just like there are many types of pumps. This can make the selection process complicated if you don’t know what you need. Fortunately, KSB Australia makes a wide variety of impellers, which can be utilised in the same pump with minor modifications to the volute.

This partner content is brought to you by KSB Australia. For more information, visit

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