Author(s)

H. Amadou, J.-B. Poulet, C. Beck & A.-G. Sadowski

Abstract

The treatment of sludge by solar drying under a greenhouse is a technique increasingly used for small and medium sized wastewater treatment plants. In order to contribute to the improvement of dimensioning and the effectiveness of the drying of sludge, we propose using the DVS system (Dynamic System of Vapor Sorption), to determine experimentally the isotherms of desorption at 30 and 50°C. These curves were modelled following a semi-empirical correlation suggested by Oswin. Consequently, experimental results of drying by the forced convection of sludge were obtained, using well controlled thermal conditions of air (30 and 50°C for the temperatures 40 and 60% for relative humidity 1.0 and 2.0 m/s for air velocity). A characteristic curve of drying is built for the different aerothermic conditions. This simplified method makes it possible to simulate the experimental kinetics satisfactorily. Keywords: modelling, isotherm of sorption, kinetics of drying, sludge, solar drying, wastewater treatment. 1 Introduction The treatment of domestic wastewater produces large quantities of residual sludge. Nowadays, wide reduction of these waste volumes is necessary to satisfy new environmental regulations [1]. Sun drying whilst covered is a technique increasingly used for small and medium sized wastewater treatment plants. The control of the solar process of drying of sludge is thus essential. Within this context, the present work

Keywords

modelling, isotherm of sorption, kinetics of drying, sludge, solar drying, wastewater treatment.