Use of the fiber-optical monitor in evaluating the state of flocculation

On-line monitoring the state of coagulation/flocculation enables automatic control of coagulation process concerning the condition of the chemical additive. In this study, a new optical monitoring technique is employed to evaluate the extent of flocculation, which involves measuring the fluctuating light intensity transmitted through a flowing suspension. This technique functions as a sensitive monitor providing an empirical index related to the state of aggregation, and could form the basis of an on-line technique. The assessment for feasible application in monitoring the flocculation through this technique is the primary objective of this study. Also, a series of batch flocculation tests is performed under different conditions. These results indicate that the fiber-optical technique is useful in monitoring the state of aggregation with different coagulants and the variation of turbidity conditions. Furthermore, a reliable index related to the floc size is provided and can be applied in determining the optimal dosage of coagulant.