CONTRIBUTION À L'ÉTUDE DE QUELQUES CARACTÉRISTIQUES PHYSICO-CHIMIQUES ET HYGIÉNIQUES DES EAUX USÉES ISSUES DE REJETS DE CERTAINES LOCALITÉS DE LA CUVETTE DE OUARGLA (SAHARA SEPTENTRIONAL EST ALGÉRIEN): IMPACT SUR LE MILIEU RÉCEPTEUR

Abstract

The basin of Ouargla has experienced during his last decades, resulting in rapid urbanization, increased by an increase in discharges of domestic sewage and industrial with all their consequences on the receiving environment dry. This field study, reveals that the sewerage of the basin, play a role of carrier of raw sewage a part of town to another, although inhabited. The physico-chemical analyzes of these waters indicate that they have a pH that does not appear to vary significantly in different water samples. But the electrical conductivity varies from site to site. This variation is a factor of two. In Ouargla, origin of water supplies has influenced one of the electrical conductivity. The temperatures of the different wastewater samples are very close to a picking area to another are between 18.8°C to 23.9°C during the study period. Suspended solids are of mineral origin namely sand, silt, clay, etc.., Representative or organic products of decaying plant or animal matter, humic or fulvic acids, for example. The chemical demand shows a variation ranging from 460 mg O2/l for wastewater from hospital to 7584 mg O2/l for wastewater Ksar. For biological oxygen demand of wastewater analyzed, it differs between the domestic and industrial wastewater. But the report DCO/DBO5 remains low. These wastewaters are characterized by a rate of NH4+ ammonium salts higher than those recommended by French standards. The hygienic characteristics of our samples revealed the existence of different bacterial species with a dominance of total coliforms, fecal coliforms and Clostridium sulfite-reducers. The latter remains responsible for the corrosion in the pipes. But during various hygienic analyzes, noted the absence of Salmonella.