Elimination de la matière organique naturelle dans une filière conventionnelle de potabilisation d’eaux de surface

Abstract

Organic matter in surface waters causes problems that are generally represented by a deterioration of organoleptic quality and a bacterial growth in pipes distribution network. It can also lead to a high consumption of chlorine and formation of organohalogen compound which are potentially toxic. The objective of this work is to study the reactivity of natural organic matter, in surface water intended for drinking, during conventional ptabilisation treatments. At first, some laboratory tests focused on synthetic solutions of humic substances, representative of the organic natural of surface waters. In a second step, the tests involved several samples of water from the dam Zit El Amba which is destined for Azzaba treatment plant. Coagulation-flocculation with aluminum sulphate alone and combined with various adsorbent materials (activated carbon, activated alumina and bentonite) was applied to both synthetic organic solutions as natural waters sampled. It was the same for the chlorination process. The results show that the removal efficiency of natural organic matter by coagulation flocculation with aluminum sulphate is significant, especially if it is combined with different adsorbents. Chlorination tests revealed significant potential of consumption. The reactivity of natural organic matter in these waters is influenced by the presence of a mineral matrix varied.