**2. The Saharan area in Algeria**

The Sahara covers nearly 90% of Algerian territory, it is crossed ergs by sand dunes, regs of stony land, as well as volcanic massifs in the far south.

In the north, the grass of the steppe slowly becomes scarce as the species change to make way for the reg. The erg, the sand desert covers only a fifth of the Sahara. The great eastern erg borders the Wadi Righ, a succession of oases, stretches along the underground wadi. The Saoura valley limits the great western erg to the west. Between these two great ergs, is the M'Zab valley carved into a plateau.

This northern Sahara, still dotted with oases, is opposed to that of the South, dominated by the Hoggar massif at an altitude of more than three thousand meters. Vast monotonous hamadas like the Tademaït plateau between El Goléa and In Salah connect the large geographical areas of the Sahara [3]. **Figure 1** present the localizations of deferent WWTP concerning in this chapter.

#### **Figure 1.**

*Situation of the study area. (a) International location map of the study area. (b) Algerian location map of the study area. (c) Regional location map of the study area.*


*Reliability and Problems of Wastewater Treatment Processes in the Algerian Sahara DOI: http://dx.doi.org/10.5772/intechopen.96113*

**Table 1.**

*Administrative breakdown [4].*

The Sahara is characterized by low rainfall, recording less than 100 mm per year. It does happen, however, that it snows and floods sometimes revive the wadis that have dried up since prehistoric times. High temperatures can exceed 45 ° C especially in summer, winter is generally mild with average temperatures ranging from 8 to 12 ° C. The subsoil is full of water in the Albian tablecloth which extends under a large part of the Algerian Sahara, a vestige of the steppe climate that the region experienced 10,000 years ago. In 2018, it is home to a population of 3,600,000 inhabitants, or 10.5% of the Algerian population. Our investigation in this document concerns 10 wastewater treatment plants in 5 provinces in southern Algeria (**Table 1**).
