| dc.description.abstract | This research thesis attempts to answer the question if a pathline analysis can be applied to a transient flow field where aquifer thermal energy storage systems (ATES) are present. This is done by constructing a simplified conceptual model of a contaminated aquifer with one ATES system and comparing a full MT3D contaminant transport simulation with a pathline analysis with and without the addition of biodegradation. If this question is answered affirmatively, the pathline analysis is applied to the case of the city centre of Utrecht, the Netherlands, to study whether ATES systems have an influence on the spreading of contaminants and their effect on contaminant concentration. In Utrecht, the subsurface is contaminated with volatile organic hydrocarbons (VOCs) and the goal of the municipality of Utrecht is to remediate these contaminated zones with the help of ATES systems. A boundary is drawn around the city centre and through a pathline analysis it is analysed whether the VOCs pass that virtual boundary with a concentration higher than a certain intervention value. The result of this study is that two of the VOCs, namely DCE and VC, pass this boundary with too high values in the first fifty years of modelling. However, from this study, it can not be concluded that the ATES systems have a direct influence on that result. | |
