While desalination could be the answer to addressing water crises in South Africa, there are still a number of financial challenges surrounding it, says Department of Water and Sanitation infrastructure and operations CEO Leonardo Manus.

Speaking to Engineering News Online at a media roundtable discussion on desalination, hosted by engineering consulting firm Gibb, on Thursday, Manus noted that, 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, and many feel that the high costs make it an unviable short-term solution.

“Desalination plants are built close to the ocean and, therefore, carry a large infrastructure and transportation cost,” he said.

Manus added that water resources needed to be looked at more critically, especially waste water.

“Unfortunately, the terminology surrounding waste water has a negative connotation. People think that because it is waste, it needs to be discarded. If we could use a different term, such as used water, there would be different concepts around it,” he said.

Manus added that there was inadequate investment in wastewater plants, despite the fact that these plants could be used as resources.

“As much as desalination is a viable source and option, the same technology is used to treat waste water. The salinity levels of wastewater are much lower than that of ocean water, which means that the energy consumption required is not as intense as for desalination processes,” he said.

Manus highlighted that while treating waste water was more economically viable than desalination, the cultural stigma surrounding reusing wastewater remained a challenge.

“The National Water Strategy makes options for the reuse of water. The master plan, which will be published in October, looks at various economically viable options regarding water treatment in terms of economies of scale,” he said.