Cape Town’s Strandfontein desalination plant is up and running. Deputy Mayor Ian Neilson was given a taste of the first 3 megalitres (ML) being produced there as rainwater dripped off his nose at the beachfront site on Monday.
“If you want it to rain, build a desalination plant,” quipped Neilson as a squall swirled around the delegation inspecting the plant built near the pavilion.
“Everything is now working,” said Neilson after doing a “blind tasting” of bottled water, desalinated water and tap water and giving the desalinated water the thumbs up.
Neilson said operations at the plant, which went online last Tuesday, were “functioning fully”.
This included the extraction of the water from the sea, treating it, getting it into the City’s water system and getting the brine water back into the sea.
“[It is] currently functioning at around 3ML a day but over the next week or so, they will be stepping that up every few days to get up to full production of 7ML a day.”
Water use still above target
He thanked Capetonians for saving water amid severe Level 6B restrictions as the City edged closer to running out of tap water in a “Day Zero” drought scare which would have required residents to fetch rationed water in containers.
Water use was brought down from an unrestricted peak of 2 500 ML per day to May 14’s figure of 554ML per day. It is still above the target of 450ML per day, and alarm bells are ringing over an increase of 6.7% in consumption.
The average level of the six dams that supply Cape Town was at 21.4% on May 14.
Neilson urged Cape Town to continue to conserve water, regardless of the rain and the rainwater augmentation projects.
The V&A Waterfront desalination plant is already producing water, Neilson explained, and will get up to its planned 2ML a day soon. The other 7ML-per day plant at Monwabisi beach will also be in operation in the “next month or two”.
“In the end it is only a contribution and we still wait for decent rains this year to ensure that our dams get to decent levels before we can talk about reducing our restriction levels in the City,” said Neilson.
The Strandfontein, Monwabisi and V&A plants are among the only desalination projects left after five were cancelled or put on hold, according to information supplied to News24 by the City independently of Monday’s site tour.
They are: Cape Town Harbour, Dido Valley/Red Hill, Granger Bay, Harmony Park and Hout Bay.
In replies to News24 earlier in May, Neilson said the City proceeded with the three small-scale temporary desalination plants at the end of 2017 once funding was made available through a special dispensation provided by the minister of finance.
“All advice has pointed towards permanent desalination; Cape Town Harbour will be considered as a potential site for such a permanent plant. All the other small-scale temporary desalination options have been put on hold or cancelled,” Neilson told News24.
Neilson said after the tasting that hardly anyone could tell the difference between bottled, tap and desalination water and the quality was shown to be “very good”. The water had also been laboratory tested.
The water would cost around R40 a kilolitre, compared to around R5 a kilolitre for dam water. The company Proxa has been contracted for two years to supply the water.
After that the plant will be decommissioned.
City still focusing on groundwater
The City’s focus is still on groundwater from dams and aquifers. The Atlantis aquifer is producing 12ML a day and drilling at other sites is still at the point of testing quality and quantity.
Neilson said that although there was rain at the moment, it was not guaranteed as there were varying predictions of the amount of rainfall to be expected.
“We cannot replicate that surface water system that took decades to build here, we cannot in a year or two replicate that quantity,” said Neilson, urging continued water saving.
The Strandfontein contract for the purchase of water was estimated to be worth between R240m to R250m and the Monwabisi contract between R250m to R260m, according to the City’s information sheet, distributed during a visit in February.
According to Wynand Wessels, project manager for contractor Proxa, the water is pulled about 750m from the shore at 15ML per day. The sea water goes through screens which remove sand, bamboo, shells and other items and it then goes through the sea water reverse osmosis process.
The only difficulties they experienced was waiting for the right tides to get the pipes laid into the sea, getting the anchored extraction system in, as well as managing inquisitive holidaymakers getting too close to the pump station on the rocks.
The remaining water is dispersed back into the sea.
By Jenni Evans. Source: News24