This field site is an unconfined alluvial aquifer consisting of Quaternary silty sand and gravel over glauconite sands. There is extensive groundwater contamination by mono-aromatic and chlorinated aliphatic hydrocarbons in the Quaternary aquifer, which is drained by the River Zenne. The source zone is complex as the area consists of a mix of residential developments and (abandoned) industrial sites, with a history of over 100 years of industrial activity. Previous studies show that the plume is strongly heterogeneous, probably due to heterogeneity in aquifer hydraulic conductivity, transport properties and in situ biodegradation capacity. The importance of chlorinated solvent attenuation by the River Zenne sediment has also been demonstrated. The groundwater monitoring infrastructure at the site comprises a network of 38 installations, which include single-screen wells and piezometers that chracterise the plume chemistry, contaminant distribution and in situ biodegradation processes for the chlorinated solvents. Remediation strategies include pump-and-treat for the groundwater plume, and soil excavation and multiphase extraction at contaminant hot spots.