• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.74-80
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• 2005

The effective removal of turbid-inducing particulates and algae-inducing phosphorous was systematically investigated by the variation of physico-chemical parameters such as pH, alkalinity, and coagulant types. Al(III)-based and Fe(III)-based coagulants exhibited high removal efficiency of turbidity and phosphorous at optimal pH ranges of 7~9, in which zeta potential nearly approached to zero. The removal rate of turbidity rapidly increased with the increase of coagulant dosages, whereas the removal rate of phosphorous gradually increased due to an equivalent reaction of phosphorous with metallic ions. The generation of flocs during coagulation was visualized by high speed camera (Motion Scope 2000, Redlake Co.), and the images of singular flocs were captured by optical microscope. The flocs generated by Fe(III)-based coagulant was more compact than those induced by Al(III)-based coagulant, and the settlabiltiy of Fe(III)-induced flocs was superior to that of Al(III)-induced flocs.