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abstract 827

The underground brackish waters in South Algeria: potential and viable resources

Author(s): Bouchekima Bachir, Bechki Djamel, Bouguettaia Hamza, Boughali Slimane, Mohamed Tayeb Meftah
Laboratoire de Développement des Energies Nouvelles et Renouvelables dans les Zones Arides Sahariennes LENREZA Université de Ouargla BP 511 30000 Ouargla Algérie *Tel : 213 73725299 Fax : 21329712627 *email : bbachir@hotmail.com

Keyword(s): Underground water- Southern Algeria –Brackish water- Solar Desalination- Water supply

Article:

Poster:

Session: Poster session 2

AbstractAlgeria disposes of a considerable amount of underground water in the septentrional Sahara. There are two

types of resources: the renewable resources, which are localised in the Hoggar-Tassili and Bechar-Tindouf valleys

and the non-renewable resources, which are contained in huge reservoirs of the two sedimentary basins: the

Continental Intercalary and the Complex Terminal aquifers. The Continental Intercalary aquifer occupies 600,000

km2 surface with a thickness reaching 1000 m in the northern Sahara. Its water is characterised by high

temperatures which can reach 60°C and over, corrosive aspect due to the presence of H2S and CO2 and a salinity

of 1–2 g/L, reaching 5 g/L in certain places. The Complex Terminal aquifer occupies 350,000 km2 surface with a

depth varying between 100 and 500 m. The water is characterised by a low salinity on the edges and a relatively

high salinity in the center, over 6 g/L. Studies concerning its exploitation estimate that a flowrate of 156 m3/s can be

used. But such an abusive utilization would not be without a negative impact from the environmental and ecological

point of view, such as the draining of low depth wells and foggaras, water quality damage and harmful water uprising

to the surface. However further studies are necessary for a better understanding of these phenomena and for

ensuring a safer and profitable use of this wealth.
Fresh water supply represents one of the major constraints to

development of such areas. The presence of brackish water of moderate salinity (2000–3000 mg/L) in some of

these areas can present an economic and reliable fresh water supply, if an appropriate desalination scheme is

adopted. The potential role of brackish water as a source of fresh water in South Algeria and the problems related to

brackish water desalination experience are discussed. A case study for brackish water desalination using reverse

osmosis (RO) scheme is presented to elucidate its feasibility as compared to other water supply options. Further,

planning guidelines for brackish water desalination are presented. The purpose of our study is to bring an alternative

solution of supply fresh water to the southern regions of Algeria.
On the other hand, the using of solar distillers

could adapted to these areas more especially as their design does not present a technical difficulties. However, their

output of fresh water remains insufficient. With a view to ameliorate their yield, our study aims at improving

condensation of the water vapour accumulated in the distiller by a natural or forced flow towards an independent

condenser. This technique constitutes a means of reinforcement of condensation and makes it possible
to improve

notably the effectiveness.

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The underground brackish waters in South Algeria: potential and viable resources