Moving bed (bio) filtration (MBF) is a mode of sand filtration based upon uninterrupted filter operation. Sand cleaning is continuous while the filter is in operation and hence a 24/7 availability of the process is guaranteed. The process features, advantages and applications of MBF are presented below. Three applications of MBF are discussed in more detail on the following subpages: biological (de)nitrification and wash waster treatment.
Process features and applications
Mode of operation
Feed water is flowing upward through the filter bed. Filtrate is discharged at the top. Solids are retained and if applicable biomass converts organic components. Filter sand is continuously sucked into the lower end of the airlift and transported vertically towards the sand washer at the top of the filter. In order to achieve this only a small amount of compressed is required to run the airlift. Sand is washed continuously by using a small volume of filtrate. If required, process air is injected into the filter bed to create oxic operating conditions for the biomass to grow.