Construction of the Potsdam Wastewater Treatment Works (WWTW) in Cape Town, currently one of the Western Cape’s largest infrastructure projects at a cost of R5.2-billion, has reached 60% completion.

Work at the Milnerton site began in April, 2023, and is progressing on schedule, says the City of Cape Town (CoCT).

The project is due to wrap up in late 2027.

Once completed, the upgrade will double Potsdam’s treatment capacity from 47-million litres of wastewater a day to 100-million litres a day.

Driving the expansion is the imperative to cater for a growing city’s water needs, says CoCT.

The project must also improve the quality of treated effluent released into the Diep river, which feeds the Milnerton lagoon, while also expanding the supply of treated effluent for reuse by businesses, farmers and recreational facilities.

Key progress to date at the ultrafiltration plant has seen the facility enter a 12-month trial operating period, as from June.

New processes and technology (including the use of micro-screening, ultrafiltration membranes and UV disinfection) are in place, and are being tested for their ability to enhance the quality of the treated effluent before discharge into the environment, as well as supply to end-users.

Construction at the treated effluent pump station at Potsdam WWTW is complete and will soon be operational following final pressure testing and putting the required pipeline connections in place.

Once active, end-users in Milnerton, Century City and surrounds will be able to access supply for irrigation or industrial uses.

The dewatering plant has been in operation since May, with full trial operations set for October.

The city says the facility is already improving biological stability and effluent quality, with noticeable reductions in solids in the treatment process.

“Successfully completing two-thirds of a multibillion-rand wastewater infrastructure upgrade project on schedule is a major milestone for Cape Town,” says CoCT Water and Sanitation MMC Zahid Badroodien.

The city believes that the present-day challenges at Potsdam WWTW, such as inflows exceeding the current design capacity, as well as sand ingress owing to sewer collapses, will all be addressed by the upgrades.

Major components still under construction include the new inlet works, membrane bioreactor treatment module, raw-sewage pump station and process control facility.

These are all scheduled for completion at the end of 2027.