Desalination experience in Morocco

The desalination experience of the National Office of Potable Water (ONEP) is closely related to the water supply in south Moroccan areas which lack fresh water and have limited brackish water resources. The desalination plants built and currently operated in these areas are located in Boujdour (MED MVC 250 m3/d and SWRO 800 m3/d), Tarfaya (BWRO 120 m3/d), and Laayoune (SWRO 7000 m3/d). The operation of these seawater desalination plants reveals the following: (1) The MED¯¯MVC process is very reliable and has a very high availability. The new version of this process (four to six effects or more) which requires an energy consumption less than 10 kWh/m3 (against 20 kWh/m3 for the old version) could compete with RO and needs to be compared to this latter process for small capacities in remote areas. (2) The SWRO process requires skilled manpower and continuous control. The cost of water seems to be more attractive than for thermal processes. In order to complement its desalination experience further, ONEP has carried out the following feasibility studies: (1) design of an MSF plant using solar energy from a solar pond. The pilot project size is 300 m3/d of potable water; (2) design of a vertical tube multiple effect distillation (VT¯¯MED) plant coupled to a nuclear heating reactor (NHR) insuring 10 MW thermal. The desalination plant was designed to produce 8000 m3/d of potable water. These studies show that desalination using nuclear energy or heat extracted from a solar pond is relatively expensive for smalls capacities of potable water. Nevertheless, they could be implemented as demonstration plants for future introduction of large-scale desalination units. This paper gives an overview of the operation of the desalination plants and draws conclusions regarding their feasibility.