COAGULATION MONITORING IN SURFACE-WATER TREATMENT FACILITIES

Coagulant dosing is traditionally determined according to results from jar-tests or operator's experience, which often lead to overdosing or -insufficient dosing. In this study, the feasibility of applying an op tical monitoring technique to determine chemical dosage and to monitor the coagulation performance in water treatment plants were assessed. To examine the applicability of the monitor under various operation co nditions, series of batch trials in the field were conducted to explor e the effects of turbidity, pH and rapid mixing intensity on the effec tiveness of coagulation. The performance was directly reflected in the output ratio of the monitor, which proved to be an effective index fo r the flee size and its settling velocity. Therefore, we consider that the optical monitor is an useful instrument in monitoring coagulation in water treatment. (C) 1998 Published by Elsevier Science Ltd. All r ights reserved.