Tube Settler Media

The Moving Bed Biofilm Reactor (MBBR) technology was developed in Norway at the Norwegian University of Science and Technology in cooperation with a Norwegian company Kaldnes Miljǿteknologi (now AnoxKaldnes AS). The MBBR is a complete mix, continuous flow through process which combines the benefits of fixed film and suspended growth processes. Benefits include increased treatment capacity, improved settling characteristics, enhanced process stability, and reduced sludge production (Metcalf & Eddy, 2003). The process can either be used as a, The MBBR process uses small plastic carrier elements to provide sites for bacteria attachment in a suspended growth medium. The carrier elements allow a higher biomass concentration to be maintained in the reactor compared to a suspended growth process, such as activated sludge. This increases the biological treatment capacity for a given reactor volume. The carrier elements are continuously kept in suspension by either a mixer or an aeration system. The agitation pattern in the reactor is designed to provide an upward movement of the carriers across the surface of the retention screen which creates a scrubbing effect to prevent clogging. Coarse bubble and jet aeration are typically used to provide oxygen for an aerobic reactor. Reports using fine bubble aeration in an MBBR system indicate the media cause the bubbles to coalesce, thereby reducing oxygen transfer efficiency.