Desalination is too costly

Our oceans offer an inexhaustible supply of water — but at a cost. (Photo: Delwyn Versamy)

Our oceans offer an inexhaustible supply of water — but at a cost. (Photo: Delwyn Versamy)

Desalination of seawater is often proffered as a solution to South Africa’s water problems. The country has a 2 500km coastline with several major ports and cities located along its length. 

And the surrounding oceans contain an inexhaustible supply of water. The problem, however, is cost.

In South Africa, bulk water tariffs run as high as R13 a cubic metre, though the average tariff around the country is less than half this amount. Estimates put the cost of desalinated water at about three times that of surface water. The process also requires large amounts of energy. Given utility Eskom’s current woes, this is simply not available in the short term.

In a recent interview,  Nomvula Mokonyane, minister of water affairs and sanitation, said she recognised the need to embrace new technologies, but was sceptical about investing in large-scale desalination, agreeing it was too costly.

“The cost is high and could not be passed on to consumers because it would make water unaffordable.”

However, desalination is an option when it comes to acid mine water.

The department is currently neutralising acid mine drainage from the Witwatersrand mines, but not removing the high salt load from the water, which is being discharged into the Vaal River system, as large volumes of fresh water are required to dilute it.

Mokonyane said the government was looking at a public-private partnerships to set up a desalination plant to treat the mine water and make it available for re-use in industry.



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