The deal with desalination in Cape Town
There isn’t one person in Cape Town who doesn’t know there’s a drought happening.
The city has been under immense pressure for the whole of the winter season due to the lack of sufficient rainfall.
The dam levels are around 23 percent currently although this figure is in a constant state of flux.
The unexpected rainfalls have not been sufficient to fill the dams and as water is used so the dams empty again.
The City of Cape Town has come up with a plan for helping curb the lack of water and assist with mitigating against the severe consequences of the drought. This plan includes the building and development of desalination plants at various sites around the Western Cape.
First off, what is desalination?
Well, in the simplest of terms, desalination is the removal of salt from seawater. The result is water that is drinkable. The detailed explanation is that water desalination can be used for brackish water, seawater, wells, surface water, wastewater and industrial feed and process waters. It is a process that separates dissolved salts and all other minerals from the water.
There are a variety of different methods of desalination. Wikipedia lists the processes as vacuum distillation, multistage flash distillation, multiple-effect distillation, vapour-compression distillation, reverse osmosis, freeze-thaw, solar evaporation, and electrodialysis reversal. The technology behind each of these methods is extremely sophisticated.
Is there a downside?
There’s only one real concern with desalination processes which is that these processes are energy intensive. Running a desalination plant requires a lot of power and after the blackouts we, experienced a few short years ago, this feels like a precarious step for the Western Cape to take.
However, running out of water and running out of electricity are two completely separate problems. After all, since the power cuts were experienced, companies and households alike have made an effort to ensure alternative power sources are available to them. But imagine almost four million people running out of water? There are no backup water supplies.
The plans for Cape Town
Granger Bay, Hout Bay, and Dido Bay have been identified as the three sites for new desalination plants in the city. This is a major decision on the city’s part and the costs involved are tremendous. But the idea is that these three desalination plants together with groundwater extraction activities and water recycling projects, will create approximately 500MI of water for the city’s residents. However, this doesn’t mean that we’re out of the red. Cape Town will need to continue to behave as a water scarce city. The drought and the effects of climate change mean that Cape Town must continue to save water and protect it as if it’s precious.
Setting up the desalination plants is in full swing but Capetonians will have to continue operating within the Level 5 water restrictions to ensure the taps don’t dry up.
These proposed desalination plants and plans to increase water availability are focused on assisting residents in Cape Town. But the major industries and businesses in Cape Town will need to continue making use of water services. The industries guilty of the most water use are irrigation, mining, bulk industrial sector, power generation and afforestation. But the heavy industrial sectors must focus their attention on using water treatment specialists, companies like PROXA Water and their counterparts, rather than use the water needed for residential areas.