Scientific chronicle : Seawater desalination

Of strategic importance

"Desalination is of strategic importance to Veolia Environnement. Seawater is an alternative source that provides a solution to water needs now and for the future."

Antoine Frérot
President, Veolia Water

Hervé Suty, director of Anjou Recherche, Veolia Environnement Group, answers questions from Pierre-Yves Maurie, writer, RMTT - Veolia Transport, about the company's research on seawater desalination

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Need to know about...

Seawater is an inexhaustible resource, but it contains 1,000 times the salt set by the WHO for human consumption.

The most frequent seawater desalination techniques

Distillation or thermal desalination: The seawater is heated to evaporation. Only the water molecules are driven off, leaving behind a deposit of salt and other substances. The vapor is condensed to produce freshwater.

Reverse osmosis or membrane desalination: the seawater is forced under pressure through a membrane filter. The salts and microorganisms are retained by the membrane. This process does, however, require preliminary treatment of the water.

Today, these two techniques roughly share half the global market each. Between 1990 and 2001, the market share of reverse osmosis rose from 40 to 53%. Veolia Environnement's research has focused on reverse osmosis, as its market share is predicted to climb to 70% (compared with 20% for thermal desalination and 10% for other methods) by 2020.

All the characteristics of the seawater to be desalinated need to be taken into account in selecting the process operation parameters to control aspects, such as corrosion, deposits and costs.

Essentially focused on the process of reverse osmosis, Veolia Environnement's research aims to optimize the operation of desalination plants utilizing membrane processes.

The research is focused on two main aspects:

• Pretreatment of the seawater to limit membrane clogging further down in the treatment process;
• Reducing the energy expenditure to cut the cost of desalination and improve the environmental outcomes.