The Potsdam Wastewater Treatment Works (WWTW) in Milnerton, one of the Western Cape’s largest infrastructure projects, has reached 60% completion. The R5,2-billion upgrade, which began in April 2023, is progressing on schedule and is expected to be completed by late 2027.
Once finished, the upgraded facility will double its treatment capacity from 47 million litres to 100 million litres of wastewater per day, catering to the demands of a growing city. It will also improve the quality of treated effluent released into the Diep River, which feeds into the Milnerton Lagoon, and expand the supply of high-quality treated effluent for reuse by local businesses, farmers, and recreational facilities.
Key progress to date
- Ultrafiltration Plant: As of June 2025, Potsdam entered a 12-month trial operating period, incorporating processes such as micro-screening, ultrafiltration membranes, and ultraviolet disinfection. These measures are being tested to enhance effluent quality before discharge or reuse.
- Treated Effluent Pump Station: Construction is complete and will soon become operational, providing end users in Milnerton, Century City, and surrounding areas with treated water for irrigation and industrial uses.
- Dewatering Plant: Operating since May 2025, the plant is already improving biological stability and effluent quality, with reductions in solids observed in the treatment process. Full trial operations are planned for October 2026.
TygerBurger has previously reported on the multi-billion rand upgrade at Potsdam, highlighting both its scale and the City’s ambitious plans to future-proof water and sanitation services for Cape Town. The project is part of a broader investment of R16,4 billion in water and sanitation over the next three years, surpassing the investments made in Johannesburg and Durban combined.
Zahid Badroodien, Mayco member for water and sanitation, told the newspaper they are future-proofing the city by investing in infrastructure at a rate far outpacing any other metro.
“Successfully completing two thirds of a multi-billion rand wastewater infrastructure upgrade project on schedule is a major milestone for Cape Town. It demonstrates our commitment to delivering critical infrastructure on time and to high-quality standards, ensuring services for decades to come.”
Addressing current challenges
The Potsdam WWTW has faced challenges such as inflows exceeding current design capacity and sand ingress due to sewer collapses. These issues are being addressed through upgrades, including the new inlet works, membrane bioreactor (MBR) treatment module, raw sewage pump station, and process control facility, all scheduled for completion by end 2027.
Badroodien emphasised the environmental benefits: “Restoring the health of the Milnerton Lagoon and improving the quality of water flowing into the catchment is a top priority for the City.”
Local residents have welcomed the progress, noting both the necessity and benefits of the upgrade.
Samantha Damons, Milnerton resident: “It’s reassuring to see the City investing in infrastructure. Cleaner water for our lagoon and the surrounding areas is something we all benefit from. However, I’m concerned about delays. Large projects like this often run over budget and behind schedule. We need assurance that this won’t drag on beyond 2027.”
Andre Magerman from Century City: “The upgrade sounds impressive, but the community hasn’t been kept fully informed about potential environmental impacts or disruptions to water supply. Communication could be better.”
