By 2040, the City of Cape Town wants to have 25% of its water supplied from alternative sources, stating that relying solely on rainfall is no longer prudent in the light of ongoing climate change risks.
Mayor Geordin Hill-Lewis hosted mayors and officials from seven cities across the world at an International Water Reuse Conference, which was held yesterday to share experiences on water reuse.
Hill-Lewis said water reuse had the potential to change the city’s water security dramatically, and they were looking at this source to add about 7% to the city’s total bulk potable water supply by 2040.
“A state-of-the-art new water scheme will be built at the Faure Water Treatment Plant and Reservoir to the east of the city.
“It will source treated wastewater from our recently upgraded Zandvliet Wastewater Treatment Works and put this through an advanced water purification process to produce drinking-quality water.
“The water will then be blended with dam water to augment the water that feeds the existing Faure Water Treatment Plant – the city’s largest water treatment plant – and then distributed into the Cape Town water supply,” said Hill-Lewis.
In line with the city’s extensive protocols, he said, this water would be continually tested using advanced monitoring that could validate the performance of any part of the treatment process in real time, along with routine daily sampling and regular sampling by independent laboratories, to ensure drinking-water standards are met.
“We are being guided in this project by an external expert advisory panel, providing not only an independent assurance of the quality of design and operation of the new water scheme but also an assurance of transparency throughout the process,” he said.
“The lessons we learnt during the drought about the value of transparency and ease of accessing information will stand us in good stead as we roll out this project in the coming years.
“If the threat of Day Zero changed something in our people – or perhaps revealed something that was always there – it also changed something in the city government and our approach to water security.”
Hill-Lewis said the big lesson was that, no matter how well-prepared you thought you were and how well invested you were in the collection of rain-based surface water, you would encounter a once-in-a-generation drought. “Or, as we did, a once-in-400-year drought – and that won’t be enough.”
Michael Kilick, the City's director of bulk services, water, and sanitation, said climate uncertainty meant they could not accurately predict water availability.
“What we do know for certain is that relying on rainfall is no longer wise. And that means the way we think about water and how we use it must change.”
He said the City wanted 25% of its water to come from alternative sources.