Insufficient measures concerning environmental protection as well as a careless dealing with dangerous substances in industrial factories lead in the last decades to a number of brownfield sites. The potential risks of such brownfields range from a damage of soil, groundwater and air to an immediate hazard of human health. Since the occurrence of these kind of problems, a wide range of environmental remediation technologies were developed. Besides classical methods like the replacement of soil, innovative techiques like the in-situ remediation of soil and groundwater are visibly emerging. At first, a range of different in-situ environmental remediation methods are presented. Based on a former realised pilot experiment of a combined thermal-hydraulic remediation, the acquired data is analyzed. This data is used for the fluid dynamical and thermodynamical computation of the remediation. Furthermore, different approaches for the calculation of a groundwater flow are presented and compared with each other. Finally, the coupled thermal-hydraulic computations are compared with the data from the prilot experiment.