Assessment of natural polyelectrolyte chitosan efficiency as the coagulant in water turbidity removal

Coagulation, Flocculation and Sedimentation are essential processes in water treatment plants. The purpose of this study was to consider the efficiency of natural polyelectrolyte chitosan as a coagulant in water turbidity removal. Chitosan is a cationic biopolymer with high molecular weight that is produced from the crust of crustaceans like shrimp and crab. This investigationwas performed on water samples containing synthetic water turbidity by applying caoline in high, middle, and low turbidities in the laboratory scale. Optimum dosage of Chitosan in turbidity removal of 1000, 500, 100, 50 and 10 NTU were 10, 6.5, 2, 1.5 and 1 mg/L respectively. Efficiency of turbidity removal were 99.77, 99.25, 94.84, 90.96 and 57.50 and optimum pH values were 8, 8, 7.5, 7.5 and 8 respectively. Chitosan has insignificant effect on water pH and its efficiency in high turbiditie's removal is more than its efficiency in lower turbiditie's levels.