Groundwater is the drinking water source for at least half of the world population. Deep groundwater does not contain pathogens, but can naturally contain iron and manganese, which should be removed for aesthetic (acceptance) and operational reasons (clogging of pipes & pumps). A widely used treatment technique for groundwater in developed and developing countries is aeration followed by rapid sand filtration: the water is brought in contact with oxygen and flows through a layer of sand. In the sand layer, physical processes combined with biological and chemical redox processes remove iron and manganese, producing clear drinking water. However, the different mechanisms of iron and manganese removal in sand filters are still poorly understood, making their design difficult and their operation often inefficient.

In the RedOx filter project, we aim to understand the fundamental mechanisms controlling their removal and to use these insights to develop new design concepts for groundwater filtration. This knowledge will help us to improve groundwater treatment around the world and has implications for the removal of toxic groundwater contaminants such as arsenic.