Desalination plants: more efficient water management through innovation

We know that water is an essential resource, but also that it is not infinite. Therefore, it is essential to focus on innovative solutions that allow us to mitigate the scarcity of this resource. Seawater desalination is an alternative that is becoming increasingly important, especially in areas where this resource is limited. As freshwater reserves decrease globally, the search for alternative sources becomes increasingly necessary.

By Celia Escribano

Water is one of the most valuable and scarce resources on the planet. According to the UN, its irregular distribution already affects up to 40% of the planet and almost half of the global population. In the case of the Iberian Peninsula, in terms of distribution, drought is a growing concern, especially in the northeast and south of the country, which according to AEMET (the State Meteorological Agency), are currently experiencing the most water stress.  In this context, the search for innovative solutions to address the shortage of such a necessary natural resource becomes especially relevant, and sea water desalination at desalination plants is a clear example of this.

The desalination process consists of separating minerals, mostly salt, from seawater through physical and chemical processes, thus obtaining fresh water that will later be treated for human, industrial, or agricultural consumption. This process generates brine, a waste that receives the appropriate treatment for its subsequent management and reuse for various purposes, or return to the sea, where its potential impact is monitored to ensure the well-being and protection of the entire marine ecosystem. 

Circular economy to make use of the waste

The water cycle itself is the perfect embodiment of the circular economy, as it is a process that naturally follows a circular path throughout its life cycle (evaporation, condensation, precipitation, infiltration, and runoff). This concept is emphasized in the case of desalination, as it involves reusing seawater, but what if the waste resulting from this process could have a second life? To further maximize the implementation of the circular economy, there are alternatives aimed at finding a second life for brine and thus making use of this waste. 

Some initiatives seek to use brine for aquaculture, contributing to the development of aquatic organisms; others for generating electricity by harnessing the difference in salinity; also for de-icing roads, especially in rural areas where snow and low temperatures are common during winter; for extracting the minerals it contains, such as calcium and magnesium; or even for preserving food such as fish and seafood, among others.

Thus, we take advantage not only of the circularity of water for its subsequent reuse, thereby achieving more efficient water management, but we can also make use of the waste derived from this desalination process and allocate it to other necessary purposes, thus closing the circle of this resource’s economy. 

What are the advantages of using desalination plants?

Desalination plants represent a promising solution that could be key in mitigating current and future water scarcity thanks to their distinctive advantages. However, to effectively and sustainably tackle this challenge, we must combine these innovative technologies with responsible water resource management and more conscious consumption.

One of the main advantages is the increase in security of the freshwater supply, but above all a more sustainable and controlled supply, since, unlike traditional water resources, it does not depend on weather conditions, which can result in periods of scarcity, but instead plants can operate continuously. Additionally, this entails a reduction in freshwater collection (especially relevant in water-stressed areas) so that it can be used for other necessary uses and, most importantly, for the local community, such as domestic consumption, irrigation, environmental conservation, and industrial use.  In addition, the quality of the water produced is also an advantage. This type of water undergoes post-treatment that varies according to the use it is intended for, in order to comply with health regulations and the quality standards required for each case. In fact, usually the fresh water obtained through desalination is of high purity, since the process eliminates most of the particles and salts contained in it.

Developing these desalination plants also greatly boosts the innovation of technologies for desalination, water treatment, and sustainable management of water resources. Although the advantages are significant, technological advances in this field are progressing to face the challenges that it presents and must be taken into account, such as the use of renewable energies to power these plants, which allow for a reduction in energy consumption by incorporating the concept of energy efficiency into the desalination process.

Spain, at the forefront of desalination 

Spain is an experienced country with a long history of desalination. Six decades ago, the first plant was built in Lanzarote, specifically in the year 1965, as well as in Ceuta, which was also a pioneer in adopting this technology to combat water scarcity. Today, desalination represents a fundamental, irreplaceable source of water supply for the country. 

This if reflected in the latest data from the Spanish Desalination and Reuse Association, which indicate that Spain is one of the countries that produces the most desalinated water, and ranks fourth in terms of production capacity behind Saudi Arabia, the United States, and the United Arab Emirates. According to these data, around 5,000,000 cubic meters of desalinated water are produced daily in Spain for supply, industrial use, and irrigation. Based on this data, Spain has a total of 765 desalination plants, of which 360 are seawater desalination plants, and 405 are brackish water desalination plants, which contains more dissolved salts than fresh water, but not as much as seawater.  

Regarding desalination plants with a production of more than 10,000 cubic meters per day, which are considered high capacity, Spain has a total of 54 plants across the various Autonomous Communities. 

In Spain, in addition to its majority use for potable water, more than 20% of desalinated water is used for agriculture, especially for irrigation and agricultural industries in the southeast of Spain and the islands. It is also used for industrial purposes in multiple processes, such as in boilers, in the petrochemical industry, or as raw material for the production of certain beverages. 

In short, desalination is emerging as an increasingly strong alternative to ensure water supply in the future and as an innovative, sustainable solution for addressing the problem of water stress through water circularity and efficient management of this precious natural resource.