The use of biological activated carbon filtration for the removal of natural organic matter and organic micropollutants from water

Amsterdam Water Supply (AWS) uses Biological Activated Carbon Filtration (BACF) for the removal of natural organic matter in general and the removal of organic micropollutants in particular. In order to minimize costs and environmental burden, it is important to know whether successive reactivations of carbon reduces its effectivity, and whether pesticides are effectively removed after prolonged running times of the carbon filters. The first aspect avoids the necessity of carbon replacement (i.e. costs), while the second aspect reduces the reactivation frequency (i.e. environmental burden). In a future extension scheme, AWS considers the use of an Integrated Membrane System (IMS), and it is important to know whether the application of BACF is beneficial in the IMS. Six years of operation of BACF in the River- Lake Waterworks (31 million m³/year) have shown that successive reactivations do not affect the DOC removal capacity of the carbon. Three years of operation of BACF in the River-Dune Waterworks (70 million m³/year) have shown that the carbon retains its pesticide removal capacity. The use of BACF in an IMS shows important perspectives in minimizing the fouling of reverse osmosis membranes and in minimizing the organic carbon content in the membrane concentrate.