Impact of sludge storage duration on its dewatering and drying ability Y.B Pambou, T. Salmon, L. Fraikin, M. Crine, and A. Léonard

Annual production of sewage sludge in Europe is estimated at more than twelve million tons of dry matter. Use in agriculture and incineration are the main ways of valorization. In this context, sludge drying appears as an essential step after mechanical dewatering. It reduces the costs of storage and transport, allows the stabilization and the hygienization of sludge while increasing its calorific value. However, sludge is a colloidal system in which particle form a stable suspension in water, making him difficult to be separated from water. The addition of polyelectrolytes chemical is necessary to help the sludge particles to agglomerate into large flocs that can be separate by mechanical dewatering. Before studying experimentally the influence of polymer’s type and dosage on dewatering performances and subsequent drying behaviour, it is necessary to assess the sludge variability during storage duration, because sludge is a highly fermentable material whose properties and composition can rapidly change.