Accidental spills and industrial discharges cause serious environmental problems all around the world. As an efficient and eco-friendly treatment method, in situ bioremediation of contaminated soils and groundwater by naturally occurring microorganisms or by bioaugmentation of adapted microorganisms is possible. Therefore, the aim of this study is to develop a generic approach for biostimulation of hydrocarbon mixture degradation present in subsurface and groundwater. A Source – Path – Receptor approach will be followed by using Griftpark, a former manufactured gas plant site, as a model case study. As a receptor, the deep groundwater used for the preparation of drinking water, will be protected by biodegradation in the Path of the present pollutants BTEX, indane, indene and naphthalene. For that purpose, anaerobic degradation of the mixture with also focus on indane and indene will be studied under different redox conditions and molecular techniques will be used to obtain insight in selection pressure to enhance the biodegradation activity of the indigenous degraders. Consequently, outcomes of this research could be applied to similar hydrocarbon contaminated sites.