A dynamic model of the clarification-thickening process

Abstract

A dynamic model of the clarification-thickening process is presented. Based on the solids flux concept and on a mass balance around each layer of a one-dimensional settler, this model can simulate the solids profile throughout the settling column, including the underflow and effluent suspended solids concentrations under steady-state and dynamic conditions. The model makes use of a special settling velocity equation designed to simulate the settling velocity of dilute and more concentrated suspensions. The model can be applied to both primary and secondary settlers to simulate dynamic and steady-state conditions. Examples based on full-scale and pilot-scale experimental data taken from the literature serve to illustrate the application of the model to secondary settlers. Results of the analysis confirm that the model can serve to predict the effluent and underflow suspended solids concentrations under a variety of conditions.