AN EMPIRICAL DYNAMIC-MODEL FOR WASTE-WATER TREATMENT-PLANT CLARIFIER SIMULATION

One dimensional models of clarifiers have been studied. In these model s clarifiers are considered as a set of layers exchanging matter one t o another in the following two ways: convection and sedimentation. The sedimentation flux is deduced from the sedimentation velocity. This v elocity can be stated as a function of the suspended solids concentrat ion only. These models induce a strong underestimation of the sludge b lanket level. This underestimation is explained because the sedimentat ion velocity does not take into account all the physics and hydraulics of the clarifier, in order to solve this point, a parametric expressi on of the velocity has been chosen. In this expression the parameter h as been fitted so that the suspended solids residence time in the clar ifier meets an empirical relation given by the bibliography. A real ca se has then been simulated using this parametric expression. The simul ated sludge blanket evolution fitted the experimental data.