Tropical lagoon and rivers treatment by coagulation-flocculation with aluminum sulphate for dissolved organic matter removal: Influence aluminum sulphate amount and pH adjustment

Natural organic matter is responsible for the formation of carcinogenic and mutagenic chlorination byproducts during drinking water production. The objective of this study is to evaluate the effectiveness of removing dissolved organic matter and turbidity with alumina sulphate during the coagulation-flocculation water. Two types of water, Me River and that of the Aghien Lagoon were subjected to test jar tests. The evaluation of the effectiveness of the treatment was determined by measuring the reduction of turbidity, UV 254 absorbance and dissolved organic carbon at pH ranging from 4 to 6.5. The results obtained show that at pH 5 - 5.5, a good elimination of the material at respective rates of plus 77,02 % and 71,68 % for  Aghien Lagoon and  Me River those of was observed. Turbidity reduction rates were 98.74% for the waters of the Me and 98.4% for the waters of the Aghien lagoon, for pH values of 5 - 5.5. These allowances were obtained for doses of coagulant of 50 and 60 mg.L -1 respectively for Me water  and those of the Aghien Lagoon. Despite the distinct nature of these water sources, the results showed similar behavior in removing turbidity and dissolved organic carbon.