Desalination in the Canary Islands: an update

The Canary Islands are subject to a continuous drought with average rainfall of about 300 mm per year. Therefore, water resources are scarce, and several islands depend strongly on sea and brackish water desalination. Over the last 10 years, an enormous development of desalination activities has taken place. This paper presents a review on the current conditions of desalination technologies in the islands. Three consecutive Regional Desalination Schemes have been agreed upon between state and regional authorities since 1988, with some 30 plants built or planned, providing over 316,000 m(3)/d production capacity in. Current capacity reaches 330,000 m(3)/d. Both distillation and membrane technologies are used, although the trend over the last years is for seawater reverse osmosis. The islands have become a live laboratory where all new developments are tested. Sizes vary widely from below 100 to 39,000 m(3)/d, and applications for product water also vary from urban supplies to industry and irrigation purposes. The modes of management have also evolved. Although main funding is from public authorities, private companies now participate actively in plant financing and operation under contract. Finally a brief section of trends on wastewater reuse and on the expansion of desalination to mainland Spain is presented.