Single and combined chemical coagulants for Oscillatoria sp. removal in raw water for water treatment plant

Abstract

Chemical coagulation for Oscillatoria sp. removal using coagulants of Alum, Polyaluminum chloride (PACl), combined PACl/Alum and combined PACl/Ferric chloride (FeCl₃) are evaluated by the jar test method to optimize the coagulant type and dosage. The synthetic water at 15 million cells/L of the concentration of algae cells is used as the raw water. The experiments conduct on a single coagulant and combined coagulant in terms of the turbidity and chlorophyll A removal performances. The results can be concluded that the maximum removal of turbidity (97.14%) and chlorophyll A (99.67%) is achieved from the combined PACl/Alum dosage (ratio 3:1 or 60:20 mg/L). The combined coagulant provides the best Oscillatoria sp. removal in comparison to its single coagulant counterpart.