The City of Cape Town has broken ground on the next phase of the R470-million Milnerton bulk sewer upgrade project, with construction of a new pipeline set for completion by 2025.

This project entails the construction of a new bulk sewer in Montague Gardens using micro-tunnelling technology.

The city will also extend and connect the Edgemead and Century City bulk sewers into the new infrastructure.

Once the nearly four kilometres of new bulk sewer is completed by early 2025, the city will divert sewage along this new line, while it rehabilitates the existing bulk sewer in Montague Drive, Montague Gardens.

Given that the existing pipeline is under the busy Montague Drive roadway, pipe rehabilitation will make use of trenchless technology.

A robotic crawler will first profile pipes to determine the best method of repair, with all the work then happening underground with minimal surface-level disruption to residents and traffic, promise city officials.

“The existing bulk sewer under Montague Drive is operating at full capacity, with an upgrade needed to accommodate future growth in this part of the city,” says Cape Town mayor Geordin Hill-Lewis.

“That is why we are constructing an entirely new bulk sewer, which will operate alongside the rehabilitated existing pipeline.

“The new pipeline will be complete in 2025, the same year as the conclusion of our major Cape Flats bulk sewer rehabilitation – the largest in South Africa.”

Over the next three years, the city will invest R1.4-billion in major bulk sewer upgrades to the Cape Flats, Philippi, Milnerton and Gordon’s Bay lines.

Water and Sanitation MMC Zahid Badroodien says the Milnerton bulk sewer upgrade includes the installation of a sand trap and screening facility at Koeberg Road pumpstation.

This promises to improve performance and reduce breakdowns caused by foreign objects entering the pumpstation.

A new 300-m-long bulk outfall sewer of 1 350 mm diameter will also be constructed at the Koeberg Road pumpstation to accommodate the combined flow of the existing and new Montague Gardens bulk sewers.

“Improving the Koeberg Road pumpstation’s operations will reduce the number of sewer spills into the Diep river and relieve environmental pressure,” says Badroodien.

“The city’s goal is to steadily restore the environmental health of the Milnerton Lagoon through a combination of infrastructure upgrades and dredging of the waterbody to remove pollution build-up.”

The City of Cape Town adds that it has exceeded its target of doubling sewer pipe replacement from 25 km to 50 km for the 2022/23 financial year ending June, replacing 55 km of pipeline.

The yearly pipe replacement target will now be doubled to 100 km a year from 2023/24, for a total investment of R850-million over the next three years.

Pipe replacement is part of a strategy to bring down sewer spills over time, says the city, including major bulk sewer upgrades, the proactive cleaning of sewer lines, the resourcing of sewer spill response teams, and utilising digital telemetry systems for early warnings on sewer spills.

These interventions have led to a 30% downward trend in reported spills in Cape Town over the last two years, based on preliminary data, says the city.