It was not until 1872 that the Aristotelian dream materialised with the first facility capable of desalinating water using solar heat, from wells in the Chilean Atacama Desert.

Later, after World War II, the first industrial plants that enabled evaporation by means of large amounts of thermal energy, were built.

In the mid-1960s in the middle of our way to the moon, another technological leap occurred: the invention of reverse osmosis membranes, the most efficient, sustainable and economic system known. But how do these reverse osmosis membranes work?

Very easy: the salty water is passed at very high pressure through an osmotic membrane that separates the H20 from the dissolved chemical components, including sodium chloride.

But the important thing is its purpose. Together with water reuse, reverse osmosis is held up as one of the great hopes for tackling several simultaneous challenges: to combat the water stress that is advancing with global warming, while ensuring supply to a growing population and closing the circle by decarbonising the economy to curb the climate change that exacerbates water scarcity.

Gap between supply and demand

The statistic of 2.2 billion human beings without access to drinking water will seem insignificant if solutions are not made widely available today.

Increasing demand for water and dwindling supplies exacerbate its scarcity in most regions of the world, including in the Middle East. Conventional approaches based on rainfall and river runoff are no longer enough, hence why unconventional water resources such as desalination are expected to play a key role in bridging the gap between supply and demand.

Only six years ago, in 2018, around 95 million cubic metres per day were sourced this way, with almost half of that amount produced in stressed regions such as the Middle East, but using practices that are clearly inefficient, if not directly counterproductive: about 70% of desalination in the Arabian Gulf was done through evaporation powered intensively by fossil fuels.

The rapid reduction in costs of electricity-generating renewable energy allows it to be used to power the reverse osmosis process, which in turn reduces the environmental impact, and hands desalination a crucial role to play in addressing the water crisis that is coming.

The reverse osmosis process generates 6.5 times less CO2 emissions than conventional desalination solutions, making it possible to produce 1,000 litres of drinkable water at a cost equivalent to that of a five-liter bottle in the supermarket.

To desalinate this amount, we use the same energy as an AC uses for one hour in a conventional house.

Turning waste into a reef

The treatment of brine (the by-product of desalination) done by ACCIONA has managed to reduce its impact through long distance discharges away from the coastline in controlled environments.

But a new process promises to reduce that footprint to almost zero by taking advantage of strategic minerals and metals. Our efforts in this process are aligned with European projects whose objective is to convert sea water desalination plants into raw materials mines using crystallisation, separation, and concentration technologies.

The recovery of metals from wastewater and brine could increase the stocks of these materials, although more information and guidance are needed on which metals to prioritise or on how technologically and economically feasible the extraction processes are.

Researchers prioritise the scarcest and most crucial metals used in basic industries as renewables — for example, lithium. This process introduces a new circular element into the cycle: the desalination plants are powered by renewables, which lowers their costs, and at the end of the cycle they produce metals to be integrated into those same renewable facilities.

Latest technology to optimise reverse osmosis processes

We implement digital solutions that optimise reverse osmosis processes by using digital twins, artificial intelligence and machine learning, in order to reduce energy consumption.

This way, it improves coordination between desalination plants and the renewables that supply energy, resulting in the benefits of complying with sustainability regulations, lowering costs and accelerating the return of the investment.

We have built more than 10 reverse osmosis desalination plants in the Middle East with a total capacity of almost 3,902,000 cubic metres per day that supply a population of around 16,065,000 people.

In conclusion, water scarcity remains a significant challenge in the GCC countries, but efforts are underway to address it through sustainable water management practices and the development of alternative water sources.

The success of these efforts will depend on strong political will, public participation, and regional cooperation.

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