Perpetual care of landfills results in high costs for future generations. My research looks at a more sustainable way of managing landfills, i.e. through active treatment. Active treatment involves in-situ aeration and recirculation of leachate through the landfill, resulting in degradation and stabilisation of the waste. If through this treatment contaminant emissions are reduced in a sufficient manner, the landfill no longer poses a risk to the environment and costly aftercare and monitoring is needed. Recently, a pilot study was started for three landfills in the Netherlands, to investigate whether this treatment is feasible. For this alternative treatment to be accepted, concrete scientific evidence is needed that the landfill’s emission potential is sufficiently reduced.