Geographia Technica, No. 1, 2012, pp. 19 to 27 WASTEWATER REJECTIONS IMPACT ON GROUNDWATER QUALITY IN A SEMI ARID REGION. CASE OF TEBESSA AQUIFER Mohamed BOUTERA 1 , Abdelkader ROUABHIA 1 , Daoud LAKHNECHE 2 , Salah ZEREG 2 ABSTRACT: Les eaux souterraines sont soumises, de plus en plus intensivement, aux rejets volontaires d'effluents polluants, eaux usées ou eau de ruissellement pluvial en milieu urbainGroundwater is exposed, more and more intensively, to deliberate discharges of polluting effluents, sewage or storm water runoff in urban areas. A l'approche des villes, les sources de contamination des eaux souterraines sont multiples et sont liées à de nombreuses activités urbainNear cities, the sources of groundwater contamination are numerous and are related to many urban activities. Les eaux urbaines constituent une source de contamination des eaux souterraines par leur concentration en constituants organique et inorganique. The urban water is a source of contamination of groundwater by their concentration in organic and inorganic constituents. D'autres sources peuvent être ajoutées telles que pollution de l'air, pluie, lessivage des chaussées,c. However, their origins can be complex and include stormwater, wastewater leakage networks. Les lixiviats d'ordures ménagères, les fosses septique sont considérés comme des sources de contamination chargées en polluants et qui ont des impacts environnementaux majeurs sur les ressources en eau disponibles. Leachates of municipal waste, septic tank are considered as sources of contamination and carry pollutants that have major environmental impacts on water resources available. Sur le sous bassin versant de l'Oued El kebir à Tébessa, l'intensification des activités industrielles et agricoles, ainsi que la diversification des modes de sous-produits de production ou des déchets après consommation, rendent vulnérables les ressources en eau souterraines. In the Oued El Kebir basin in Tebessa, increased industrial and agricultural activities, and the alternative by-products of production or post consumer waste, make groundwater resources vulnerable. The plan changes leading to changes in groundwater levels by pumping in urban areas can also lead to contamination of interconnected flows. The impact may be a hydrological from substantial exploitation of the resource has an action on the hydrodynamic behavior of the aquifer. In this perspective, we try to examine the state of the groundwater resources of Tebessa plain, the last cut by the Oued El Kebir, which drains the wastewater from the entire urban area of the city and which location can contaminate groundwater. Keywords: groundwater, wastewater rejection, urban area, Tebessa aquifer. 1. INTRODUCTION Wastewater can have a significant impact on the quality of groundwater. Nitrate and chloride pollution of surface water is of high concern as it may have negative impacts on water supply and ecosystems (Postma et al. 1991 et al., Rouabhia et al. 2004, 2008, Baali et al. 2007). High nitrate concentrations in water serving as a source for drinking water is a serious health problem, being known for many years as the cause of blue baby syndrome and related to increased levels of diarrhoea of children (Fehdi et al. 2008). Wastewater Irrigation may increase the salt, nitrate, and chloride concentrations of the receiving water bodies, limiting their agricultural, industrial, urban, and ecological uses. 1 University of Tebessa, Department of Earth Sciences, 12002, Algeria. rouabhia22@yahoo.fr. 2 University of Batna Algeria. zs_hcds@yahoo.fr; bet.hydraulique@gmail.com.