Hydrogeological multiphase-multicomponent simulations of a PCE polluted site

Due to the long-term percolation of chlorinated hydrocarbons from the former factory Piquerez into the soils, the Canton of Jura declared the site as polluted area with need for action. Since 2012 multiple studies have been carried out to quantify the current concentrations and to investigate the hydrogeological flow regime. Due to the reusage of the former factory buildings, drilling and sampling methods are only applicable to a limited extend. TK CONSULT AG has therefore been commissioned with the development of a detailed flow and transport model that helps understanding the dominant processes that led to the current situation. Later the model should also serve as tool for the validation of remediation measures.

Due to the complexity of the model, the project was divided into three phases:

• Creation of a 1-phase regional model to map the general flow conditions. The results also serve as boundary conditions for the local model.
• Extension of the 1-phase model to a transport model to validate the flow simulation results.
• Creation of a 3-phase-3-component model using iTOUGH2 for a detailed simulation of the transport processes.

The multicomponent-multiphase model delivered important feedback on the dominant processes that led to the todays observed situation. On this basis, the originally assumed amount of deposed PCE could be corrected and further project steps could be planned. We would like to thank Dr Stefan Finsterle (Finsterle GeoConsulting) for the review of our iTOUGH2 model and the helpful discussions as well as the Geotechnical Institute and the Office for Environment of the Canton of Jura for the good cooperation.