Modélisation du comportement des matières en suspension à l'effluent d'un décanteur primaire lamellaire

Abstract

Process modelling can prove a useful tool for the control of wastewater treatment plants. The objective of this research was to verify that a primary settling model developped for a conventional process is applicable to a process using lamellar settling. The lumped-parameter model examines the hydraulics of a system composed of stirred tank reactors in series and simulates suspended solid concentration of the effluent under various flow regimes. The model has been validated using data collected from a pilot lamella settler of a capacity of 15 m3 and operated over a wide range of flows (Hazen velocity between 0,43 and 2,59 m∙h−1). The prediction of the model was in agreement with the observed values both in terms of concentration and hydraulic behavior of effluent suspended solids (average relative error of 17%). How ever, less satisfactory was the model performance tested with the concentration data on settleable solids. Research is under way to study the different mechanisms of sedimentation going on in the settler. Key words: modelling, lamellar settling, settleable suspended solids.