Sidestreams characterisation in view of their valorisation

The main characteristics of sidestreams from primary and secondary sludge treatment, or from post-digestion treatment, are presented and analysed. The concentrations and fluxes of various components (suspended solids (SS), volatile suspended solids (VSS), chemical oxygen demand (COD), N, P, major ions) are necessary for selecting and designing the treatment or recovery processes for these returns. They show significant variability depending on the processes implemented on the water and sludge lines of the facilities, particularly for phosphorus removal or sludge pre-treatment prior to digestion.