Modeling and Optimization of Natural Coagulant for Surface Water Treatment

The objective of this study was to develop a treatment system that can effectively reduce the concentration of colloidal particles in raw water. Among the various techniques, coagulation and flocculation is the conven- tional method used to remove colloidal substances. Sago starch is used as a coagulant. The influence of pH, temperature, coagulant dosages on the coagulation process was studied and conditions were optimized corresponding to the best removal of colloids, color, total solids, chlorides, hardness and decrease in turbidity. 100% reduction of colour from raw water was achieved by using the op- timum coagulant dosage (0.1 and0.2g/l) in the optimum pH range (6 and7). 70 - 100% reduction of turbidity was also achieved in the same optimized conditions. Higher dosages did not significantly increase pollutant removal and were not economical. The results provide useful information for raw water treatment with sago.