Drinking water from the sea as a chance for the future?

WWF study has explored possibilities and limitations of seawater desalination

Seawater Desalination Plant © WWF Canon / Michel Terrettaz
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More than a billion people have no access to clean drinking water - and the number is rising. More and more countries around the world are relying on desalination of seawater. But that's just a sham solution. This is the result of a new WWF report, which deals with the possibilities and limits of water extraction from the sea.

Growth market desalination

Currently, more than 10, 000 seawater desalination plants are in operation worldwide. They produce about 31 million cubic meters of drinking water every day. This would be enough to provide around half of EU citizens with water. The growth potential of this industry is huge. Worldwide, this capacity is expected to double by 2015. Pioneers are countries such as Saudi Arabia, Australia and Spain. China is also aiming for a tripling of its plants by 2020.

"Although 95 percent of the planet's water resources are stored in the world's oceans, desalination is costly, energy-intensive and associated with fatal ecological side effects, " says Martin Geiger, Head of Freshwater at WWF Germany, summarizing the report's findings. "With the plants, the problems grow."

Large systems require so much energy that you basically have to build your own power plant next to it. This in turn leads to an increase in greenhouse gas emissions and contributes to climate change and ultimately to increasing drought in many areas. In addition, the huge industrial plants spoil large coastal areas and the extracted salt is returned as brine back into the sea. This changes the salinity of the sea, which in turn has negative impacts on fish stocks, corals and aquatic plants in the affected coastal areas.

No improvement for the poor

The water supply for the poor will not improve in the opinion of the WWF through the desalination of seawater. For this, the process is far too expensive. "Especially in arid countries, for example in the Mediterranean or Australia, merciless water is wasted. Through dilapidated pipelines a significant portion of the precious material seeps unused into the ground, "explains Martin Geiger. In particular, agriculture is a key sector. 70 to 80 percent of water consumption goes to agriculture. display

In some cases, a desalination plant may be useful, admits the WWF report. However, before embarking on a major development, careful use of the resource water for man and nature is the more efficient, better and cheaper way. Before a plant is planned and built, all options of water saving in agriculture, the rehabilitation of water supply networks and the possible use of treated wastewater must be carefully examined.

(WWF, 25.06.2007 - NPO)