Moving bed biofilm reactor is a type of wastewater treatment process that was first invented by Prof. Hallvard Ødegaard at Norwegian University of Science and Technology in the late 1980s. It was commercialized by Kaldnes Miljöteknologi. There are over 700 wastewater treatment systems installed in over 50 countries
The MBBR system consists of an aeration tank (similar to an activated sludge tank) with special plastic carriers that provide a surface where a biofilm can grow. The carriers are made of a material with a density close to the density of water (1 g/cm3). An example is high-density polyethylene (HDPE) which has a density close to 0.95 g/cm3. The carriers will be mixed in the tank by the aeration system and thus will have good contact between the substrate in the influent wastewater and the biomass on the carriers.
To prevent the plastic carriers from escaping the aeration it is necessary to have a sieve on the outlet of the tank.