The City is considering sites to build new sewage plants to treat effluent discharged from its three marine outfalls at Hout Bay, Green Point and Camps Bay.
The City’s proposed sites for the plants are the sports fields close to the Green Point outfall pump station; a space directly adjacent to the Camps Bay outfall station; and a site in “close proximity” to the Hout Bay outfall pump station, between Main Road and the Hout Bay River.
Last year, the City held a series of meetings to gauge public views on sewage disposal from those marine outfalls.
A scoping study set out the options for new plants at an estimated cost of R6 billion, excluding annual increases in construction costs.
“Marine outfalls are built to safely release screened effluent far from the shore, where waste is diluted to very low levels by the vastness of the ocean, with naturally occurring biological methods helping to break down harmful bacteria,” said the City.
“Historically, outfalls have been utilised mostly in urbanised areas where it is difficult to find suitable space for treatment plants on land.”
The City’s three marine outfalls at Green Point, Camps Bay and Hout Bay discharge beyond the intertidal zone while all other areas in the city are serviced by 23 sewage plants from where the treated effluent is released into the environment.
The City said 95% of wastewater was discharged from the sewage plants compared to 5% from the three marine outfalls.
Mayoral committee member for water and sanitation Zahid Badroodien said there was still a lot to do before plans could be implemented, but the City was committed to finding the best way to treat effluent optimally while prioritising public and environmental wellbeing and still considering factors such as the terrain and available space.
The City had presented all possible future alternatives listed in the scoping study during the public participation period for the review of the permits for the City’s three marine outfalls, he said.
“It is important for the public to remember that implementing these options will be subject to available budget and the results of feasibility and environmental impact assessments. The City will continue engaging with the public on this topic in future.”
Dr Badroodien said the scoping study had identified future alternatives to marine outfalls, which included new sewage-treatment plants.
The Athlone, Bellville, Macassar, Potsdam, Wesfleur and Wildevoëlvlei sewage plants were undergoing upgrades at an estimated cost of more than R2.5 billion while an estimated R140 million would be needed to upgrade the marine outfall plants, he said.
“The City initiated the comprehensive scoping study to explore future alternatives for treating effluent discharged from the three marine outfalls. Immediate efforts are focused on short-term strategies for refurbishment, replacement, and maintenance to extend the lifespan of existing treatment infrastructure,” said Dr Badroodien.
A 2022 research paper led by Professor Leslie Petrik, group leader of environmental and nano sciences at UWC, flagged the presence of emerging contaminants in the marine environment and their potential impact on marine life and ecosystems, particularly within the protected reserve.
“Over a sampling period of six months from March to September 2016, acetaminophen (paracetamol), diclofenac and carbamazepine were reported to be present in sewage effluent discharge from the pump station of Camps Bay, and it can be assumed that these concentrations being discharged into the bay remained relatively stable over the ensuing year,” the paper says.
It adds that chemical contaminants from sewage make regular landfall, giving rise to a build-up of chemical contaminants around the seashore.
Despite the findings, the City maintains its dedicated water pollution control unit investigates incidents of non-compliance.
The City said an independent external auditor, in an April 17 report, had confirmed City effluent test results for effluent flow, metal, chemical and bacteria sample analysis that found an average compliance of more than 97% across the three marine outfalls – 100% at Green Point and Hout Bay and 91.7% at Camps Bay.
Caroline Marx, from the anti-pollution group Rethink the Stink, said she would like to see Department of Forestry, Fisheries, and Environment Minister Barbara Creecy impose shorter timelines for coastal discharge permits (“Raising a stink about sewage in our sea,” Atlantic Sun, October 23, 2023).
“Improved treatment is needed to protect both human water users and aquatic life from the daily onslaught of micro-plastics, disease-causing micro-organisms and chemicals contained in the millions of litres of raw sewage currently being discharged into Cape Town’s underwater nature reserves.
“The 2019 Hout Bay permit required the City to submit a treatment improvement plan which was not done. It’s hoped that there will be no more unnecessary and unacceptable delays,” she said.
