Optimization of flocculation processes with respect to the physical parameters

Abstract

Conventional water treatment usually include coagulationflocculation processes. Flocculation is influenced by several factors, both physical and chemical. The study presents: short notes on coagulation - flocculation theory, principles, and practice; a brief review of literature on the physical aspects of flocculation with special reference to flocculation kinetics. A rational approach for optimizing the physical parameters of flocculation is presented. The optimum combination of velocity gradient, G, and time of mixing,T, has been suggested for raw water turbidities and temperatures normally encountered in water and their possible applications in process design and control discussed. At a given temperature, the optimum G value, Gopt' and the optimum power function, Gopt.Topt, have linear relationships with the logarithm of the raw water turbidity value. There is also a linear relationship between the logarithms of Gopt and Topt at all temperatures and turbidity values. For a given turbidity, optimum G and T values are higher at lower temperatures while for a given temperature the optimum values are higher at lower turbidity values.