NEW INSIGHTS IN DYNAMIC MODELING OF A SECONDARY SETTLER .2. DYNAMICALANALYSIS

A dynamic model of the settling process in the secondary settler of a wastewater treatment plant is given by a nonlinear scalar conservation law for the sludge concentration under the form of a partial differen tial equation (PDE). A numerical algorithm is given, which also includ es a mathematical model of the aeration tank. Theoretical and numerica l simulations are then compared with real data. The evolution of the s hock corresponding to the rising of a sludge blanket is described by a n ordinary differential equation (ODE). Consequently, regulation strat egies of the rising of a sludge blanket in case of important water adm ission to the plant are proposed. We end briefly with two possible ext ensions. A model with two classes of particles in interaction is intro duced to take into account the particle size change, as well as a mode l giving the distribution of residence times to take into account its effect on the velocity. (C) 1997 Elsevier Science Ltd.