Desalination: South Africa’s initiatives
South Africa announces a program to examine possibilities of desalination as a process for producing drinkable fresh water from sea water.
(Lamberts Bay Desalination plant – photo: Veolia)
In May 2016, Reuters reported as follows:
South Africa has partnered with Iran to develop desalination plants along all coastal communities to boost water supplies, Water Minister Nomvula Mokonyane said on Wednesday, as the worst drought in living memory dries dams.
South Africa last year record its lowest annual rainfall levels since comprehensive records began in 1904 as an El Nino-driven drought rips through the region, putting millions at risk of food shortage.
“Now with the partnership that we have entered into through the binational commission between South Africa and Iran we want to go full steam,” Nomvula Mokonyane told reporters.
She said the first investment meeting with Iran, where President Jacob Zuma visited in April, takes place next month and that there were no indicative costs at this stage.
The largest desalination plant in South Africa, which converts salty seawater to drinkable water, is situated in Mossel Bay along the Western Cape where it helped supply water to state oil company PetroSA’s gas-to-fuel refinery.
“We have been over-dependent on surface water,” Mokonyane said, adding that government would focus on all coastal municipalities in three provinces, including the Western Cape and KwaZulu-Natal.
South Africa’s weather woes have been largely attributed to a powerful El Nino system, a warming of ocean surface temperatures in the eastern and central Pacific that occurs every few years with global consequences. – Reuters
The National Water Commission added:
“There are significant difficulties from this drought,” Dhesigen Naidoo, chief executive of the National Water Commission, told Environment 360. “The drought cannot be managed the way previous droughts have been managed. In previous droughts we hadn’t factored in climate change. We are convinced that this drought is not part of a normal drought cycle that we’ve had in the past. This one is quite different. So we regard this as a drought in the climate change scenario, and our planning is working around that.”
Department of Water and Sanitation director-general Margeret Diedericks says “South Africa was also looking at examples in Dubai where solar power was being used to power desalination plants.”
Present significant desalination plants in operation in South Africa.
Mossel Bay. According to the contractor, Veolia:
The desalination plant supplies 10,000 cuM of potable water to Mossel Bay Municipality daily and 5,000 cuM of process water to PetroSA.
The plant is supplied directly by an open sea water intake about 600m from shore. Water is pumped to a pump station, and then into a holding tank via drum screens, which screen incoming water to 500 microns or 0,5mm to get rid of kelp, sea shells and other impurities.
Water then passes through six filters before going to the reverse osmosis units for purification. The treated water is then fed from the plant into split tanks. A dedicated tank of 5 megalitres is designed to supply PetroSA as industrial process water.
The 10 megalitres of water is treated chemically to kill any bacteria and stabilise the pH balance, before joining up with the municipal water line.
This potable water treatment plant is the largest seawater desalination plant in South Africa to date. It is separately reported that the capital cost of this plant was R191 million.
Read more about the Mossel Bay plant here.
Lamberts Bay desalination plant.
The completion of the Lamberts Bay desalination plant by Veolia is set to contribute significantly to socio-economic development of Lamberts Bay area along the West Coast.
The plant was initiated due to the inadequate supply of potable water and unsustainable abstraction of water from boreholes in this Cederberg Municipality town. Several studies were conducted in 2008 and it was approved that potable water be augmented by an additional borehole and a seawater desalination plant for Leipoldville and Lamberts Bay. The plant which came into full operation during the second quarter of 2014 at an approximate cost of R 17 million, will produce 1,700 cuM of drinking water per day and is designed to be expanded to a production rate of 5,000 cuM of water per day.
As part of the solution, Veolia installed an innovative energy recovery system which recycles the excess pressure energy from the brine back into the system in order to compensate for high energy required to power the high-pressure pumps. This plant uses approximately 3.75 kW of electricity per cubic metre of potable water produced.
Read more about the Lambert’s Bay plant here:
Other coastal desalination installations:
The Lambert’s Bay contract follows six other desalination plants installed by Veolia along the Cape coastline since 2009 (Cannon Rocks, Bushman’s River Mouth, Knysna, Plettenberg Bay, Mossel Bay and Saldanha), with a combined desalination capacity of approximately 25,000 cuM per day