WASTEWATER URBAN REJECTIONS IMPACT ON GROUNDWATER QUALITY IN BÉCHAR CITY (ALGERIAN SW), IN URBAN ENVIRONMENT UNDER AN ARID CLIMATE

Abdesselem KABOUR, Azedine HANI, Lynda CHEBBAH

ABSTRACT: This work treats the problem of the urban wastewater (sewage) influence identification on the groundwater chemistry, in particular the quality parameter in an urban environment, under an arid climate in Béchar city, located at the Algerian Western south. The ability of this groundwater for consumption is treated by comparing its chemical composition to Algerian standards, according to which half of the wells is not potable, whereas those of the World Health Organization (WHO) qualify the majority of samples by drinkable ones. The irrigation suitability is also examined, where the distribution of the samples is variable among different classes, were the projection of some points is except Wilcox diagram (very bad quality). The determination of the chemical facies allows the different groups identification and their changes over time, and factors influencing this mineralogical mobility. The main identified facies are chlorinated calcium, and chlorinated sodium. Microbiological analysis (total germs, Total Coliforms, Streptococcus, Clostridium Sulfito-reducer) including research organisms indicator of sewage pollution (fecal coliforms) is also carried out, confirmed and interpreted by microbial load sizeable presence, the largest is located south of the city. Studying the spatiotemporal variation of the chemical and microbiological composition of groundwater in Béchar city identifies the intensity of this impact that influx directly on its quality.

Keywords: Quality, groundwater, hydrochemistry, microbiology, urban wastewater, Béchar.

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