Although KSB Pumps began in Germany more than 150 years ago, the company has established a substantial South African footprint over the past several decades, with local manufacturing and service facilities – a presence that enabled its South African operation to lead the full design and development of a self-priming wastewater pump for local conditions.

The new ELN 150 pump is also known as Imvubu – the isiZulu word for ‘hippo’. It takes its name from an animal known for its toughness and resilience, qualities reflected in the pump’s ability to handle demanding wastewater conditions. Imvubu is the result of several years of design work, prototyping, hydraulic optimisation and field testing.

“South Africa’s wastewater infrastructure is under immense strain with limited resources and ever-rising sewage volumes. We listened to the market. Customers highlighted issues ranging from frequent clogging and solids carry-over to difficult seal replacement, maintenance complexity, thin casings that wear quickly and designs unable to handle raw, unscreened sewage. The KSB Pumps and Valves team used this input as the foundation for Imvubu’s design,” says Hugo du Plessis, market area manager: water, wastewater and irrigation, KSB Pumps and Valves.

To avoid frequent clogging, Imvubu features a large 77.3 mm free passage to handle the wipes, rags and debris commonly found in municipal networks, reducing the risk of blockages and spillages. This exceeds the global raw sewage benchmark of 76 mm. “The free passage is what sets it apart. This design is market leading and equates to the fact that if a pump can pass a bigger solid, it will clog less. It is that simple, and less clogging means less callouts, less downtime and less cost. In real-world operation, that 1.3 mm can be the difference between uninterrupted pumping and a costly blockage,” adds du Plessis.

“This pump was designed for African conditions, which is why it can be maintained with basic tools and speed-adjusted through simple pulley changes.”

“It can also do the job of two pumps simply by moving from low to high heads and low to high flows easily with no need for a second pump. It can even be mounted on diesel skids for remote pumping or flood emergency use. It is versatile, strong and practical,” he states.

With flows up to 430 m³/h and heads of up to 48 m, the pump offers high efficiency, grease-for-life bearings (eliminating oil changes), and a rotating assembly that can be removed without disturbing pipework. An inspection hatch allows quick access through just two bolts, making routine maintenance faster and safer. Designed from first principles and extensively tested in local plants, Imvubu provides a durable, energy-efficient and environmentally responsible solution for wastewater applications.

Municipalities and industry operators often have to deal with pump failures in remote areas and need equipment that is easy to service in places where skills are often scarce and uptime is critical to prevent spills.

The Imvubu pump therefore features bearings-for-life with no oil lubrication required. Unlike competing pumps that require oil chambers, top-up checks and contamination risk, the KSB Imvubu pump uses grease-for-life bearings and KSB’s own mechanical seal which is lubricated by the pumped medium itself. This makes the pump environmentally cleaner, safer to maintain and significantly simpler to service. The pump body is also cast with thick, heavy-duty volute walls to resist erosion and extend operating life, while its smart design includes an inspection hatch that allows staff to clear blockages without removing the suction cover which is a major advantage for treatment plant technicians and municipal maintenance teams.

The Imvubu pump was developed using advanced CFD (Computational Fluid Dynamics) modelling and efficiency redesigns of the impeller, volute and hydraulic passageways. The result is significantly improved pumping performance, now reaching more than 65% hydraulic efficiency which places it well ahead of competitor self-priming pumps currently in service.
Applications extend beyond municipal wastewater to mining sumps, industrial effluent, pulp and paper, agricultural waste dams, river abstraction and portable dewatering units.

Two long-term field trials were completed before the launch. At the Drakenstein wastewater treatment works, the pump ran for more than 5 000 hours with almost no measurable wear on the impeller and minimal wear on the wear plate. At a paper mill in Nelspruit, the pump achieved more than 1 300 operating hours without blockage, even while handling high-pH effluent.

By comparison, competing imported pumps at the same sites typically experience weekly blockages. Several operators reported that the reduced clogging lowers the risk of spills, reduces operational downtime and limits emergency maintenance.

KSB is already seeing regional interest from other African countries. Utilities in Nigeria have placed initial orders, and the pump is being positioned for broader sub-Saharan markets where robust, low-maintenance wastewater equipment is in demand.

A South African development

“The launch of Imvubu demonstrates our commitment to localisation and showcases the country’s growing engineering capabilities. Imvubu is the first solid-handling self-priming pump developed within KSB’s global group to be engineered and manufactured outside Europe or Asia,” adds du Plessis.

He adds that South Africa continues to spend billions of rands annually, importing equipment that could and should be produced locally. “In sectors such as water infrastructure, energy, and mining, imported pumps and related systems account for a significant share of procurement budgets. Through initiatives led by the Department of Trade, Industry and Competition (DTIC), and with partners like KSB, we are deliberately working to reverse this trend — to build industrial depth, protect supply chains from global disruptions, create skilled jobs, and retain value within our borders. We are proud of that fact that Imvubu will be registered on the DTIC Local Content Register within the new year. This new pump supports the public procurement bill’s intent to prioritise local content.”

Du Plessis emphasises that localisation cannot succeed in isolation; it relies on sustained collaboration across the sector.

“Government must provide policy certainty and enforce local content requirements, while industry invests in capacity and innovation. State-owned enterprises play a key role by integrating local content into procurement planning, and research and training institutions must continue to develop the artisans and engineers needed to support long-term industrial growth. The message to all stakeholders is clear: localisation is not about protectionism, but about improving competitiveness, strengthening capability and ensuring long-term sustainability.”

As one of the top three pump companies in the global wastewater sector, the KSB Group now extends that strength through Imvubu, which positions the South African operation as a significant exporter of high-value engineered products into sub-Saharan Africa and other regions needing similarly robust, versatile pumps.

KSB’s Johannesburg operation employs more than 400 people and manufactures between 50 and 70 pumps per day, with the ability to double output by 2030. The company is also expanding capacity with new machinery, upgraded testing facilities and plans for a larger factory across the road from the current site. The factory sources castings from several South African foundries and maintains extensive machining, testing, coating and assembly facilities. KSB invests in new machining technology annually to maintain production accuracy and consistency and has a Level 1 Broad-Based Black Economic Empowerment (BBBEE) rating.

“The development of the ELN 150/Imvubu shows that South African facilities can not only assemble equipment but also design, engineer and test high-performance wastewater technologies from first principles. The project demonstrates the value of investing in local capability and the opportunities available when manufacturers respond directly to local operating conditions. Our Imvubu pump is a direct answer for many of the failures making national headlines and the timing in this period of regeneration could not be more significant. Municipalities and utilities urgently need equipment that can keep working away with minimum attention and maintenance to clear the backlog – and we are proud to say the answer is the KSB Imvubu. As municipalities continue to face blockages, spills and infrastructure strain, the availability of a robust locally built solution provides a practical step toward improved wastewater reliability and industrial competitiveness,” concludes du Plessis.

Operating characteristics of ELN 150/Imvubu:

• Maximum flow: 429.4m³/h
• Maximum head: 47.6 m
• Suction size: 150 NB (6”)
• Discharge size: 150 NB (6”)
• Solids handling: 77.3 mm
• BEP flow: 305 m³/h
• BEP head: 33 m
• BEP ŋ: 65%
• Temperature: up to 80°C.