Numerical tools for sediment management in sewers: Application to storage-settling basins

The storage of urban wet-weather wastewater in basins seems to be a promising solution for pollution control of combined sewerage systems. Since the geometry and the operation of storage-settling tanks are often very complex, the usual design methods become unsuitable. Hence, there is a growing need for new tools to assist engineers in designing and/or managing such storage structures. A mathematical model for solids transport in sewers (SIMBADD, Simulation Mathématique des Bassins De Décantation) has been developed and implemented into CFX-4.3. This contribution concerns the simulation of the water surface boundary and the bottom sediment exchange. The bed boundary conditions are related to the turbulence features that are quite well described by computational fluid dynamics (CFD) models. This paper also presents an example of application to a real storage-settling basin under construction in Marseille (France).