Microbial Activity in Activated Carbon Filters

To obtain information on the adsorption, bacteriological oxidation and desorption processes in filters, the oxygen consumption (ΔO₂) and the removal of organic carbon (ΔTOC) as well as their relation to one another (ΔC/ΔO₂) were studied. The results show that bacteriological activity in activated carbon filters can make an important contribution to the removal of organic substances both in the water and on the activated carbon. This activity was dependent on various factors such as the water temperature, contact time, type of activated carbon, the running time of the filter, number of attached bacteria, and composition of the influent water. At steady state 0.010 g of carbon was oxidized per hour by 10¹¹ attached bacteria at 20°C and pH 8.0, which was measured in filter and in batch experiments. It is important that water treatment plants with activated carbon filters make use of the bacteriological activity and benefit from it as a contribution to water treatment. In terms of bacteriological activity the activity of the slow sand filter (0.4 m/hour) was comparable with the activated carbon filter (4 m/hour).