It may be hard to swallow, but from next month many Cape Town residents could be drinking treated sewage water from their municipal supply.
The first wave of purified water from a demonstration plant set up at the height of the 2016-2018 drought could be injected into water mains within weeks for a two-month trial. A full-scale permanent reuse plant will be ready in 2026.
The temporary use of demonstration plant water surprised one of SA's leading water scientists, who is concerned about the possible harmful health impacts of chemical compounds left over in the water - such as hormones and antibiotics.
However, Cape Town insisted the use of treated sewage water is safe - and a vital ingredient for long-term water security.
"There is a high level of confidence in the city's proposed plant design and the eventual safety of the product within the scientific and engineering community, as well as excitement around the social and environmental benefits this technology will bring," said Xanthea Limberg, the mayoral committee member for water and waste.
• 48.5% - Public support for potable water reuse in times of drought
— mixed feelings on sewage
She said the permanent plant in Faure was due to be completed by 2026, and water from the demonstration plant would be phased in gradually, building up to 5-million litres a day.
She confirmed there had been no formal public participation process for the demonstration plant.
After going as low as 20%, Cape Town dam levels recovered before the emergency plant was commissioned, said Limberg. "It was therefore repurposed into a demonstration plant for extensive water quality testing and for larger scale water reuse."
A report to the council water and waste committee this week said the treated sewage water would be added to the distribution network in central and southern suburbs from March to May.
Public support for ground water extraction
Source: Water Research Commission survey, 2019
— 50.2%
However, Limberg said the use of demonstration plant water for human consumption still needed final approval.
Treated sewage water is used in Beaufort West, which suffers periodic water shortages, and in Namibia.
Prominent water scientist Leslie Petrik, a professor in the University of the Western Cape chemistry department, said she was one of the academics consulted about the project but had yet to see detailed toxicology reports on water from the plant.
She said traces of female hormones had been found in Beaufort West's reused water.
Jay Bhagwan, of the Water Research Commission, said waste-water treatment technology and processes were constantly being improved, and direct reuse for drinking and other purposes was increasingly being "mainstreamed".
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