The MBBR (Moving Bed Biofilm Reactor) system is considered a biofilm process. Biofilm processes in general require less space than activated sludge systems because the biomass is more concentrated, and the efficiency of the system is less dependent on the final sludge separation. MBBR systems don’t need recycling of the sludge. The MBBR system is often installed as a retrofit of existing activated sludge tanks to increase the capacity of the existing system.
