Multiple interventions in place to improve operations at Koeberg Sewer Pump Station

25 February 2024

Increased sand and foreign debris have been found in the inflow to the Koeberg Sewer Pump Station, which negatively impacts the pumps, causing frequent failures. Although the City has been diligently maintaining the pumps, significant flow surges may periodically cause the system to backwash and overflow via emergency discharge points. 

Although the City has made great strides in restoring the Milnerton Lagoon, pollution has regrettably persisted due to a string of unanticipated incidents.

The 12 collapses in Montague Gardens during the past few months, on the 900mm diameter fibre cement pipeline, are the primary cause of the significant sand intrusion. This is mainly due to ageing infrastructure, which is approximately 50 years old.

Another cause for system failures is high sewage flows, putting pressure on the entire sewer system. Additional complexities are presented when the need for repairs arises. Due to the depth of the pipeline excavation, typically measures 5m below the surface.

The R470 million Milnerton Bulk Sewer Improvement Project has been instrumental in earmarking the area's deteriorating sewage infrastructure for phased replacement.

'Long-term improvements to Koeberg Pump Station will cost R118 million, with the installation of a sand trap and screening facility being the first to be completed. The goal is to finish this project in 2025. Furthermore, from 2026 to 2028, Koeberg Pump Station will be re-constructed to increase overall capacity,' said the City's Mayoral Committee Member for Water and Sanitation, Councillor Zahid Badroodien.

As an interim measure, various interventions are in place to manage overflows during peak times including:

• A diesel-operated mobile pump installed to alleviate pressure. When necessary, the pump acts as a backup, turned on to manage sewage overflows.
  
  
• Completed installation of a 610m-long rising main connected to the mobile pump. This addition helps to channel excess flow directly from Koeberg Pump Station to Potsdam, reducing the amount of effluent that Koeberg's four pumps have to process.
  
• The City has ordered four pump impellers which will reduce redundancy. Four new pumps for Koeberg Pump Station and two for Racecourse Pump Station are due for delivery in May 2024.
  
• When an issue arises the internal Engineering and Asset Management team collaborates closely with the Pump Station Maintenance team on site to perform mechanical repairs and restore pumps to full functionality.
  
• The Montague Bulk Sewer line repairs, which are complete.
• Water and Sanitation is in the process of relooking the design of the berm, to make it more effective in containing spills from the pump station. Progress will be communicated as the matter progresses.
  

Published by:
Media Office, City of Cape Town