Chemtrap: a hydrogeochemical model for reactive transport in porous media

The TELEMAC system has been extended recently to deal with groundwater flow. In this paper we deal with subsurface contaminant transport applications of the TELEMAC system. Once released into groundwater, contaminants interact chemically with both the native water and the rock matrix. Interphase reaction such as sorption or precipitation are of primary interest because they considerably alter the contaminant mobility, Transport models frequently handle these interactions by using the partition coefficient (K d ) approach, assuming a constant ratio of sorbed and soluble contaminants. In the near-field of a nuclear waste repository chemical interactions need to be modelled more rigorously. This paper summarizes the conceptual model, the numerical techniques and the software architecture chosen for the development of a coupled hydrogeochemical model based on existing separated transport and chemistry modules, Some validation lest cases, as well as a first application to the near-field of a nuclear waste repository, are also discussed. The TELEMAC system turns out to be a particularly convenient host for such multidisciplinary software.