Optimizing physical parameters of rapid mix design for coagulation-flocculation of turbid waters

Conventional water treatment usually begins with rapid dispersal of chemical coagulant(s) into raw water followed by vigorous agitation. This process, commonly referred to as initial or rapid mixing, is influenced by several parameters, both physical and chemical. The paper presents a brief review of literature on coagulation-flocculation of turbid waters with special reference to the kinetics of rapid mix. In the light of the limitations of previous research, a rational approach for optimizing the physical parameters of rapid mix is presented. The optimum combination of velocity gradient, time of rapid mix and container geometry has been suggested for raw water turbidities normally encountered in practice.