Advantages and disadvantages of desalination plants

desalination plantsdesalination plants
desalination plantsdesalination plants

Advantages and disadvantages of desalination plants

With the recent drought that South Africa has been experiencing, people are clamouring for a solution. This solution has been provided in the form of desalination plants, some of which are in production in the Western Cape. With some of the seawater desalination awarded to PROXA and other companies, these plants are set to provide clean drinkable water in the near future.

Below are some of the advantages and disadvantages of desalination plants and what these mean for their future use.


The advantages of desalination plants


They provide accessible drinking water

This is arguably one of the major benefits of a desalination plant, the fact that it provides accessible drinking water to those who need it most. This applies even to countries who have fresh water but are experiencing times of drought or natural disaster.

By removing dissolved salts and other minerals from seawater, desalination plants turn salty water into fresh potable water for drinking. Saudi Arabia gets 70 percent of its fresh water via the process, meaning that it is highly beneficial for desert and drought-stricken countries.


They help with habitat protection

Desalinated water meets, and often exceeds, water quality standards. This means that they help to reduce pressure on freshwater sources that may need to be protected.

Because these plants treat seawater, rather than removing water from freshwater sources, they are preserving habitats for endangered species. Seeing the ocean as public water supply can even help to promote awareness of the plight of our oceans, further helping sea creatures to live a better life and for rubbish to be dumped more responsibly.


They provide water to the agricultural industry

Desalination not only provides potable water but water that is safe for use in irrigation of plants and water for livestock. This is great for arid regions where farmers may not have direct access to a steady supply of water or areas that are experiencing a drought, much like South Africa.

Because farmers will be able to use the water to produce their own crops, they will not be reliant on imports and will help to improve the economy of their own country. They will also be able to produce enough food to sell and feed their own residents, keeping hunger at bay. Livestock farmers will better be able to water their livestock without using their drinkable water sources to do so.


The disadvantages of desalination plants


They consume a large amount of energy

Opponents to desalination have pointed out that it is not feasible due to the fact that it requires a significant amount of energy to operate. The distillation process requires millions of gallons of saltwater to be boiled at high temperatures before it is potable.

Reverse osmosis uses a large amount of energy to overcome the natural osmosis process and remove large particles from seawater by using a semipermeable membrane. As a long-term solution, it might not be the best solution due to the high energy consumption needed for the different processes. However, in the future, this hurdle can be overcome with some ingenuity and technological advances.


High costs to build and operate

Desalination plants can be expensive to build and to operate. These costs can run from R30 to R240 million to build and operate, which may not include equipment and worker training.  They can also be expensive to maintain and these costs are affected by the energy price changes.

Operating costs include creating systems and training employees to use the equipment efficiently and effectively. Some studies say that ‘desalinated water is five times more expensive to harvest than freshwater, making it too costly for the average consumer’’. This expense can be debilitating tot eh communities who may not be able to afford to build one in their arid or drought-stricken regions.


The environmental impact can be high

While desalination plants can help to stop species endangerment, it is also possible that they can have a negative environmental impact. The salt has to be disposed of, and in such large volumes, it can be highly difficult to do so.

Chlorine and other chemicals are often added to the water during processing and left behind with the brine which, if dumped back into the ocean, will bring many harmful substances with it. It can also cause stress and damage to animals who are not used to highly saline water. This negative environmental impact can be remedied with intelligent dumping solutions from engineers who work at the plant.



Desalination plants can be highly beneficial for arid areas or places that are experiencing intense drought, but it is important to weight out both the pros and cons before anything is decided about the construction of one. It has both positive and negative environmental impacts, and the costs could weigh out the benefits in a poorer country.

desalination plants