Geochemical modelling of a sludge deposit: first results
Résumé
Over the lifetime of vertical flow constructed wetlands, a sludge deposit layer at the surface of the first stage of the system is formed. This deposit layer is highly organic, but contains also several minerals, including nutrients and metallic trace elements. The interactions between the constituent are complex. A better description is however necessary to predict the retention and/or the release of the elements of interest under the
effect of different environmental parameters and according to different operating conditions. The main objective of this study was to define as precisely as possible an organo-mineral assemblage, representative to the chemical behaviour of the sludge deposits. The use of a geochemical model could make possible to predict the leaching of the elements depending on the chosen scenario, and evaluate their potential impact on the environment.