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Sea water desalination: a solution for turning the tide on the water scarcity crisis?

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As water shortages continue causing havoc in a growing number of regions around the world, an age-old idea is experiencing a surge in popularity. Since there is so much water in our oceans, why don’t we tap into the seas to satisfy our vital needs? Desalination processes are actually very old. Take a trip back to ancient times and Aristotle was already describing how Greek seafarers used evaporation techniques to distil seawater aboard their boats. What about in the modern world? What progress has been achieved in desalinating sea water to meet today’s fresh water needs?

Fresh water, a fragile ressource 

Planet Earth: 2,5 % fresh water… locked away in hard to access areas

According to figures published by the United Nations, close to 4 billion people live with severe water scarcity for at least one month of the year. A quarter of the planet’s population lack access to safe drinking water, and a third do not have access to sufficient sanitation services1. 

These difficulties can be explained by the Earth’s fundamental geological structure. On Earth, 97,5 %2 of water is stored in seas and oceans, but its high salinity level means that it is unfit for human consumption. But water resources would be in abundant supply if the remaining 2.5% were not mainly concentrated in glaciers and the polar ice caps, or locked away in aquifers. These layers of rock are permeable or fractured enough to absorb the rainwater leaching into the ground.  

As a result, people can only count on less than 1% of the hydrosphere (rivers, lakes and near-surface groundwater) to quench their thirst and meet their sanitary, agricultural and industrial needs. 

Number 6 in the United Nations’ sustainable development goals (SDG) aims to guarantee universal access to water and sanitation, which has been specifically defined as follows: between 50 and 100 litres of water per person per day, with a cost not exceeding 3% of household income, and with a water source within 1,000 metres of the home and a collection time not exceeding 30 minutes. 

Fresh water shortages exacerbated by the human factor

The planet’s geological formation is not the only culprit, since water crises are also being aggravated by various human causes:  

  • Growth in the world’s population, which is accompanied by a continual rise in the amount of water drawn from our renewable fresh water reserves, with over two thirds used to irrigate crops. These reserves are also being increasingly contaminated by toxic substances released into the environment and the lack of wastewater treatment facilities.
  • Climate change, which is shaking up the natural fresh water cycle, where the repercussions are still hard to model with any real accuracy. The rainfall system seems to have been disrupted in many regions around the world, with floods and droughts occurring more frequently and striking with increasingly devastating effects, while higher sea levels are raising the salinity level of the coastal aquifers that billions of people living along the shorelines rely on for their fresh water supply. 

Desalinating water: a solution for tackling water stress? 

The Arabian Peninsula has met most of its fresh water needs since the 1970s by building desalination plants. In addition to improving water use efficiency and investing in treatment and reuse infrastructures, desalination tends to be one of the solutions that public authorities can harness to limit water withdrawals from renewable fresh water reserves to sustainable levels. 

schéma Tedagua

VINCI subsidiary Tedagua built its first desalination plant in the 1980s and has since developed solutions to meet a wide range of needs. Some projects are contracted by local authorities, like the plant that Tedagua constructed and operates in Béni Saf in Algeria, which produces 200,000 cu. metres of fresh water every day. Others are commissioned by industry professionals to supply fresh water to their production sites. 

Tedagua also builds desalination units that can be incorporated into standard containers, meaning that they can quickly and easily be deployed in response to a temporary and isolated water shortage emergency, such as if the water networks are damaged in the wake of a natural disaster. 

How do you desalinate sea water?

What are the challenges with desalinating water? 

VINCI subsidiary Tedagua built its first desalination plant in the 1980s and has since developed solutions to meet a wide range of needs. Some projects are contracted by local authorities, like the plant that Tedagua constructed and operates in Béni Saf in Algeria, which produces 200,000 cu. metres of fresh water every day. Others are commissioned by industry professionals to supply fresh water to their production sites. Tedagua also builds desalination units that can be incorporated into standard containers, meaning that they can quickly and easily be deployed in response to a temporary and isolated water shortage emergency, such as if the water networks are damaged in the wake of a natural disaster. 

Tedagua, a VINCI subsidiary and desalination expert, is responding to these challenges by investing heavily in innovation and focusing its efforts on enhancing the energy efficiency of the reverse osmosis process (such as through electrodeionization) and developing alternative solutions. 

We are working with academia, research centres and industrial partners to pioneer disruptive technologies. 

Javier Hidalgo, CEO of VINCI subsidiary Tedagua.

Sources :

https://www.who.int/news-room/fact-sheets/detail/drinking-water 

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