Utilisation des énergies renouvelables dans le dessalement : Cas de l’Algérie

Abstract

A huge geothermal aquifer is located in the northern Algerian Sahara, with brackish water free from toxic inorganic compounds and organic matter. Therefore, this water is appropriate for good quality potable water production after partial desalination. This paper deals with the basic desalination plant design considerations in the context of overall optimal aquifer exploitation. The main types of criteria for such optimization are economic and environmental. Implementing the concept of “blending” reservoir water (at appropriate proportion) with desalinated water, allows cost-effective and environmentally attractive resource exploitation; the latter would be achieved by re-injecting the retentate (after desalination) free from any chemicals that may degrade the reservoir water quality by accumulation over the years. Results are summarized of a typical case study based on low pressure reverse osmosis membrane desalination. Key RO membrane performance data from a pilot unit are employed in support of this study. The results highlight the main features and the constraints in plant design and desalinated water recovery; constraints are mainly imposed by the need to avoid membrane scaling with no use of undesirable synthetic anti-scalants. The proposed cost-effective plant configuration and operating mode are in accord with the overall optimum resource exploitation. A cost analysis is also performed for a typical potable-water production plant. Finally, possibilities are outlined of integrated exploitation of this geothermal reservoir, whereby energy is extracted in addition to potable water production.