Optimization of coagulation/flocculation for phosphorus removal from activated sludge effluent discharge using an online charge analyzing system titrator (CAST)

Coagulant dosing is traditionally based upon jar-tests or operator experience, resulting in either overdosing or insufficient dosing. In this study, we assess the feasibility of a new coagulant dose control instrument, the online charge-based automatic titration system, charge analyzing system with titrator (CAST), to determine coagulant dosages from active sludge effluent discharge in municipal wastewater treatment plants. Results show that treated total phosphorous (TP) concentrations were successfully lowered to less than the site's 0.5 mg/L limit indicator level. These results suggest that the CAST system to be a very useful automated chemical dosing instrument for the coagulation/flocculation process in wastewater treatment plants (WWTPs).