This field site is located on an unconfined sandstone aquifer, which has been contaminated by phenolic compounds (phenol, cresols and xylenols) from a former tar-acid distillation plant. Previous research shows that the phenolic compounds are biodegraded in the aquifer under a range of redox conditions (from aerobic respiration to methanogenic fermentation) and that biodegradation processes are strongly influenced by the contaminant matrix. The groundwater monitoring infrastructure at the site includes a network of single screen monitoring wells and multilevel samplers (MLS). The MLS have sampling points at intervals of 0.25-1m, which provide high-resolution monitoring of the plume chemistry, contaminant distribution and in situ biodegradation processes, including detailed analysis of the bioreactive plume fringe at the interface between the background groundwater and plume. A pump and treatment system is currently in operation at the site, as part of the plume management strategy.