City one step closer to desalination

Construction of the Strandfontein desalination plant at Strandfontein Pavilion is well under way.

The City of Cape Town says its short- to medium-term water augmentation plans, which include three reverse osmosis desalination plants, as well as aquifer abstraction and water recycling, is on track, with the first desalination plant at Strandfontein Pavilion set to produce an eventual 7 million litres of water a day as next month.

Day Zero, the day when residential water supply will be turned off and people will have to queue at water collection points for their daily allocation of 25 litres of water, has been moved back to Friday May 11 after farmers in the Overberg would be releasing between 8 and 10 million cubic metres of water into the Western Cape supply network from next week.

Xanthea Limberg, the City’s mayoral committee member for informal settlements, water and waste services and energy, said during a tour of the R240 million Strandfontein Pavilion plant last Thursday, that the production starting time at the Monwabisi desalination plant had been delayed by four weeks “as a result of community dynamics”. This plant is also meant to deliver 7 million litres of water a day.

“In the case of Monwabisi, residents want a larger stake in the contract – 30% of the overall contract rather than 30% of the local labour component,” said Ms Limberg. “This was difficult for the City to accommodate because a significant amount of the entire project is the hiring of the plant to assemble elsewhere, off-site. So, it is difficult for us to attach a larger component to work that is not done on-site as per the local labour prescription”.

She said there were, however, multiple engagements with residents and the community will still be benefiting from economic opportunities and job creation although not to the scale they initially desired.

Ms Limberg said there were weekly steering committee meetings and much of the work was now continuing at Monwabisi.

The contract for the Strandfontein and the Monwabisi plants was awarded to Water Solutions South Africa-Proxa South Africa JV (Joint Venture) after a tender process last year. According to the City, the Strandfontein contract was worth between R240 million and R250 million and the Monwabisi contract, between R250 million and R260 million.

The Monwabisi project is due to come online about a month after the Strandfontein plant. Exact dates will be communicated by the City.

Speaking about the Strandfontein plant, Wynand Wessels, project manager for Proxa South Africa, said as a temporary installation plant, most of the plant came in was pre-manufactured, containerised units. He said equipment will be positioned on-site, followed by a period of electrical connections and piping after which it will go into operation of two phases , with Phase 1 producing an initial supply of 2 mega litres (2 million litres) of water a day and Phase 2 the period when the final supply of 7 million litres a day will be supplied.

Phase 1 is due from March and Phase 2 from May. The plant will be running for a 24-month period after which the area will be rehabilitated.

Strandfontein, Monwabisi and the V&A Waterfront are the three sites identified for temporary desalination plants while other augmentation projects include optimising water from the Cape Flats aquifer, the Table Mountain aquifer and the Atlantis aquifer. These are expected to yield 80 million litres, 40 million litres and 30 million litres a day respectively from 2018 to 2020.

Asked if the City had not left water augmentation plans till too late, Ms Limberg said given that there were factors outside their control, such as climate unpredictability, it impacted their ability to accelerate implementation, but they were taking action outside their core competency such as adding to the bulk water supply to ensure that a Day Zero scenario is not reached.

She said Day Zero was modelled on different factors – evaporation, consumption, both urban and agriculture “and understanding how all those things impact and being mindful of controlling demand.”

We asked bathers at Strandfontein Pavilion if they knew what the construction next to the breakwater of the tidal pool was all about. “No, I don’t,” said Darren Davids of Athlone. “I was wondering what is happening there. I thought they’re just taking rocks from the pool.”

After hearing that it was the first desalination plant to become operational, Mr Davids said he was glad to hear about it. He said water-saving actions in his home included only flushing the toilet when it was absolutely necessary.

Junaid Motala, also from Athlone, said Day Zero was the wake-up call that everyone needed. He said it is unfair on those who tried their best to conserve water if others were not doing the same. “Everyone needs to be on the same page,” he emphasised.

Mr Motala and his friends said they suspected sewer blockages would be some of the major problems we’d experience in the event of Day Zero.

Sherozaan Nordien, from Strandfontein, said the construction of the plant was a good thing as extra water supply was needed in the current crisis.

Her mother, Noerjawaan Nordien, said when she first heard of Day Zero it was scary and she was in a panic. “I thought of the children first – where would one get water for them. Already bottled water is sold out in Mitchell’s Plain. We drove to Fish Hoek for water the other day and eventually found water in St James.”

Ms Nordien said the situation could be greatly improved if everyone practiced water-saving at home and schools educated pupils too.

The provincial government is finalising plans to keep schools open in areas most affected by the province’s crippling drought.

Premier Helen Zille unveiled plans on Wednesday January 31 to principals of schools dependent on the Western Cape Water Supply System at a meeting at the Western Cape Sports School in Kuils River.

Schools use about 2% of the City’s water supplies.

Ms Zille said: “Cape Town can still avoid Day Zero if all residents use less than 50 litres of water a person, a day. This must be the first priority. However, the provincial government must be ready to augment water supplies to schools, if consumption targets are not met and our dam levels reach 13.5% before the winter rains. At this point the City of Cape Town intends to turn off water to most areas in the metro, in order to manage and preserve the remaining supply. Our job is to make sure schools remain open and operational, with adequate alternative water supply to do so.”

Officials of the Western Cape Education Department and the Department of Transport and Public Works have surveyed the needs of schools over the past six months to ensure water security at schools, to ensure water for hygiene and fire security, and drinking water.

The overall objective is to ensure that schools remain open after Day Zero. In the very worst case scenario, areas dependent on the Western Cape Water Supply System may be without surface water until August.

“Schools have mainly used water from the reticulation systems of municipalities. Our main focus now will be on ensuring that schools have the additional facilities they need to source, store and use augmented water supplies, up to and beyond the anticipated Day Zero. Officials have developed plans based on overall needs and are now finalising the needs of individual schools,” said Ms Zille.

“The departments investigated what schools already have in place to source and store augment water supplies; what schools still need; and timelines for further action.

“Most of the planned interventions cover supplies of non-potable water to schools, for hygiene and fire security. Potable water from some boreholes and packaged water will cover drinking needs.”

The main water sources in the short term are: limited municipal water; groundwater (from boreholes), recycled water; and sea water. Where water is not potable, drinking water will be delivered to the schools.

A total of 407 schools in the province (27%) have existing boreholes. Of these, 308 (76%) were functioning at the time of the survey. Fifty-eight are producing potable water, and 349 are producing non-potable water.

Service providers are standing ready to drill a further 10 boreholes at strategic points to supply groups of schools that have no or insufficient local source of water. They are also working to rehabilitate as many of the non-functioning boreholes and those that are in a poor condition to bring them back into service.

Thirty-one schools are currently drawing recycled water from the City’s treated effluent water network, that covers many areas of the city.

Thirteen wastewater treatment plants produce 162 million litres of recycled water every day. The network covers 222 kilometres of pipework under the City.

Schools can use this water for toilets, as long as they isolate the supply from other water supply systems. Officials will work with the City to map schools to the network, to enable them to draw recycled water for their ablution facilities as well as for fire security.

The City can also provide recycled water at stand pipes or directly from wastewater treatment plants if they are unable to connect schools directly to the treated effluent water network.

The provincial government will consider sea water in cases where schools cannot access borehole or recycled water for sewage purposes.

Medium- and longer-term plans include accessing water from broader augmentation projects, including water from aquifers, planned desalination plants, and the City’s plans to extend the recycled water network.