EAUX USEES EPUREES DE L’AGGLOMERATION D’OUARGLA : GESTION ET CONSEQUENCES ECOLOGIQUES

Abstract

Like other major Algerian cities, the agglomeration of Ouargla removes large volumes of purified wastewater (PWW) able to generating negative impacts on the environment.Our study objective was to highlight the current management policy of the PWW. The management of PWW derived from the basin of Ouargla aims, to medium term, the mobilization of these waters for irrigation. In the short term, almost all of these PWW is rejected in nature. Informal reuse in irrigation in some sites has been detected. The receiving environment of the PWW is « Sebkhat Safioune », it‟s an isolated area of about 10.000 ha located approximately at 40 km north of the city of Ouargla. The site of reuse most represented is a few hundred meters to the north of treatment station of Ouargla, it contains more than twenty plots irrigated with PWW and mainly planted of date palms, the PWW reuse in this site is neither organized nor controlled. PWW rejection has created ecological changes in the receiving environment previously barren, generating a water area of about 600ha, installation of flora and birdlife, rising water table and accumulation of wet organic matter are the main impacts observed. On the other hand in the reuse site, irrigation with PWW led to the rise of ground water.