The plant can also operate manually in the event of a power outage a feature made
Maintenance is minimal, because of the plant’s gravity-based design.
The government and the Water Utilities Corporation (WUC) are this week celebrating a major national infrastructure milestone, the successful completion of the one-year Defects and Liability Period (DLP), the new Multibillion Pula Mmamashia Water Treatment Plant, one of the largest and most advanced in Southern Africa.
Built at P1.3 billion, the state-of-the-art facility has officially passed its one-year Defects and Liability Period (DLP), confirming its reliability and full functionality.
The project, executed by Khato Civils, stands as a model of African engineering excellence conceptualised, designed, and delivered by an African company for Africa.
The new Mmamashia plant, located just outside Gaborone, has the capacity to treat 110 million litres of water per day. When combined with the older Mmamashia plant of equal capacity, total production reaches 220 million litres daily. Added to this is another 64 million litres from the Masama wellfields, giving Botswana an impressive 284 million litres of treated water per day.
What makes the project exceptional is not only its scale but also its operational efficiency. The plant is designed to function primarily on gravity, dramatically reducing energy costs.
It draws water from multiple sources, including the North-South Carrier, Gaborone Dam, and Bokaa Dam, ensuring continuity even when one source is offline.
Since commissioning in October 2024, the Mmamashia plant has not only strengthened water security for Greater Gaborone and surrounding villages but has also become an educational and tourism attraction. Engineering students from institutions such as the University of Johannesburg have visited to learn from its design and operation, and more international universities have expressed interest.
Project materials such as steel pipes, valves, and joints were sourced from South Africa due to limited local availability, but Khato Civils managed to keep the project within budget by supporting local suppliers. This shielded the project from currency fluctuations as the pricing contracts were in Pula rather than US dollars.
Visiting the plant offers a refreshing and educational experience. The facility’s design allows visitors to follow the intricate water treatment process, a blend of advanced technology and natural gravitational flow.
Project Manager Allen Mamombe explained that the plant, officially commissioned on 22 October 2024, was tested beyond its design capacity, successfully handling between 120 and 150 million litres per day during trial runs.
“The plant has performed beyond expectations,” he said. “Throughout the entire defects liability period, there were no unplanned water shortages in Gaborone District, only planned maintenance.”
The treatment process begins at the inlet tower, the plant’s highest point, which receives raw water and reduces pipeline pressure. From there, the water flows by gravity to the blending chamber, where pre-chlorination and cougulant dosing are carried out. These initial chemical processes help suspended solids settle in the clarifiers that follow.
The plant has six clarifiers, though it can achieve its full capacity using only four or five at a time. The sixth remains on standby for use during the rainy season when raw water carries higher sediment loads. After clarification, the water flows naturally to the filtration building, where it undergoes sand filtration, a trusted and robust method that removes remaining micro-organisms.
The filtration process is monitored and controlled from a state-of-the-art control room, making the plant fully automated. Operators can manage the system using the Supervisory Control and Data Acquisition (SCADA) interface, requiring only minimal staff.
Importantly, the plant can also operate manually in the event of a power outage, a feature made possible by its gravity-fed design.
Following filtration, the water moves to the post-chlorination stage at Mixer 4, where final disinfection using chlorine dioxide ensures the treated water meets Botswana Bureau of Standards (BoBS) drinking water specifications. The system includes five chlorine dioxide generators serving both the new and old Mmamashia plants.
Currently, the new plant processes around two-thirds (67 percent) of the water supplied to Greater Gaborone, while the older plant handles the remainder. Together, they provide a stable and sufficient supply to meet the region’s growing demand. The new facility integrates seamlessly with Botswana’s existing water infrastructure. In addition to its main reservoirs, the plant features an extra 40-million-litre storage tank, known as MBR, which temporarily holds treated water before it is pumped into the broader distribution network. This supplements the long-standing 880-megaliter storage system already in operation.
Khato Civils successfully integrated all reservoirs and pipelines, ensuring flexibility in water routing between facilities. Water from the Masama wellfields, developed as part of an 87-kilometre pipeline completed in 2021, adds another layer of resilience. The borehole water requires minimal treatment, needing only chlorination at Mixer 4 before entering the reservoir system.
From the reservoirs, four 800-kilowatt KSV pumps equipped with Variable Speed Drives (VSDs) distribute treated water to the Greater Gaborone area, Forest Hill, Kanye bypass, and other southern parts of the country. Over the past year, WUC closely monitored the plant to detect any defects during the DLP. The results have been exceptional. “Our operational uptime has been 100 percent; there has not been a single day when we failed to deliver the required water output,“ Mamombe said. He noted that maintenance needs are minimal, largely because of the plant’s gravity-based design and the absence of complex pumping systems. Even in cases of citywide power outages, water continues flowing into the storage reservoirs, ready to be pumped to distribution stations once electricity is restored. During the past year, Khato Civils worked closely with WUC staff, providing comprehensive training on plant operations, safety procedures, and maintenance.
This has ensured a smooth transition as the company prepares to officially hand over the facility. “We have spent the year transferring skills and knowledge to WUC, they are now fully equipped to operate and maintain the system efficiently,” Mamombe added. The success of the Mmamashia project has drawn attention across Southern Africa. Delegations from countries such as Lesotho and Eswatini have toured the facility, eager to learn from Botswana’s example. Visitors have been particularly impressed by the combination of large-scale output, energy efficiency, and automation achieved through mostly gravity-driven engineering.
For Botswana, the Mmamashia Water Treatment Plant represents more than a technical achievement, it is a symbol of national resilience and innovation.
Conceived at a time when the country faced growing water demand and supply uncertainty, the project has now become a cornerstone of water security for the capital and its surroundings.
The completion of the DLP marks the beginning of a new phase where WUC takes full ownership of a plant that stands as a beacon of sustainable design and African capability.
“Visiting the plant gives you pride; you see what we have built as Africans for Africa and you feel the cool breeze as water flows through this magnificent facility. It’s both refreshing and inspiring,” Mamombe said.
Dikarabo Ramadubu
BG Reporter
Botswana Guardian
October 24, 2025
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