Desalination and its importance

Desalination is the process of removing salt and other dissolved minerals from seawater or brackish water to produce fresh water suitable for human consumption, agriculture, and other uses and is carried out in desalination plants, which employ a variety of technologies.

It is common to come across the words desalination or desalting to refer to the same concept, and in both cases, we would be right. According to the dictionary of the Royal Spanish Academy, to desalinate is: 1. To remove the salt from seawater or brackish water to make it drinkable or useful for other purposes. On the other hand, desalting is defined as 1. To remove the salt from something, such as jerky, salted fish, etc. 2. To desalinate. Therefore, although desalination is a more precise term than desalination, they could be used interchangeably when referring to water.

The importance of desalination in water resources management lies in several aspects:

1. Access to additional freshwater: In many regions of the world, access to freshwater sources is limited or insufficient to meet growing demands for potable water, so desalination provides an additional source of fresh water, reducing dependency and helping to meet the needs of communities and industry.
2. Water scarcity mitigation: In water-scarce areas, such as arid or drought-stricken regions, desalination can play a crucial role in mitigating water shortages. It allows diversification of supply sources, which is essential for water security.
3. Water security: Desalination can contribute to water security by providing a reliable source of water that is not dependent on unpredictable climatic factors such as rainfall. This is especially relevant in areas prone to drought and climate variability.
4. Agricultural applications: The availability of freshwater through desalination is crucial for agricultural irrigation, maintaining food production in water-deficit areas, and contributing to food security.
5. Industrial and commercial use: Industries and businesses that require large volumes of water for their processes can benefit from desalination, reducing competition for limited water resources.
6. Climate change resilience: Desalination is an important response to climate change, as rising temperatures and droughts can affect freshwater availability. Desalination can help ensure a constant supply of water under changing climatic conditions.

The need for desalination is often related to freshwater scarcity, which can be caused by factors such as rapid urbanization, population growth, drought, overexploitation of aquifers, water pollution, and climate change. Coastal and arid regions are most likely to face desalination needs due to a lack of access to natural freshwater sources and increasing demand for water for domestic, agricultural, and industrial use.

Saline water sources

Saline water sources, primarily seawater and brackish water, are vital in the consideration of desalination. Each type of saline water source and the regions facing desalination needs are described below:

1. Seawater: Seawater is the most common water source in desalination. It contains a high concentration of salt (approximately 35,000 parts per million or ppm) and other dissolved minerals. Desalination of seawater involves removing the salt and converting the water into fresh water. Coastal and arid regions with limited access to freshwater sources often resort to seawater desalination. Examples of such regions include parts of the Middle East (such as Saudi Arabia, the United Arab Emirates, and Israel), southern California in the United States, Australia, and parts of Spain.
2. Brackish water: Brackish water is found in underground aquifers and surface sources and has a lower salt concentration than seawater but higher than freshwater. Salt concentration can vary widely and desalination of brackish water involves the partial removal of salt. Regions facing aquifer contamination problems or relying heavily on brackish groundwater sources may require the desalination process. This includes coastal areas, areas of intensive agriculture, and areas with saline water intrusions into aquifers.
3. Other sources of saline water: In addition to seawater and brackish water, there are other less common sources of saline water, such as saline lakes and saline wastewater. Desalination of these sources may be necessary in specific situations. Regions facing problems of contamination of freshwater bodies or wishing to reuse treated wastewater may consider desalination from these sources, although it is less common than desalination of seawater and brackish water.