Waterworks processing groundwater may need a removal of iron and manganese to prevent deposits in their pipelines. To this end, iron and manganese are oxidised with Oxygen and retained as insoluble oxide particles in filters. Stoichiometrically, the oxidation of iron and manganese requires only small amounts of Oxygen. Therefore this is usually carried out by air which is limited by its efficiency. A proper Oxygenation system provides the DOC levels needed for supporting the oxidation.