Desalination site selection on North-African coasts

The North-African coasts are characterized by a severe hydric stress while the potable water demand keeps increasing; this situation implies inter alias the implementation of desalination equipment with judicious types and locations. Site selection for a desalination plant is a very challenging task as various aspects are affected such as technical criteria, costs, time schedule, environmental impacts as well as political-social-human factors. All parties are concerned, not only governments but also lenders, general public, investors, utilities. This presentation will focus on the sequential steps from data gathering till final decision making. The sites comparison will involve a large range of topics such as for example, potable water demand, seawater intakes and outfalls, subsoil conditions, fresh water and power availability, accessibility, seashore line protection, local labor and infrastructure, regulations, etc. This requires multidisciplinary teams to work together not only to cover all individual elements but also to tackle the interdependences between them. A key choice will be the selection of the desalination process type i.e. thermal processes (multistage flash, multieffect distillation), membrane process (reverse osmosis) or hybrid process (mix of thermal and membrane processes): this decision, among others, is linked to either existing power generation - grid or power demand as well as to the raw water quality. While site selection decision making is an issue, one should not overlook the importance of the plant overall layout. As an illustration of the above considerations, several North-African coast sites are reviewed.