The main characteristic of Moving Bed Biological Reactor (MBBR) configurations is that there is no sludge recycle from a secondary clarifier. MBBR is essentially a simple, once-through process, where all of the biological activity takes place on the biomass carriers. MBBR is usually followed by a solids separation system such as a secondary clarifier or DAF, in order to separate bio-solids produced in the process from the final effluent. The main advantage of MBBR is robust and simple reduction of soluble pollutants (soluble BOD or COD, NH4+, etc.), with minimal process complexity, utilizing a significantly smaller footprint when compared to conventional aerobic treatment methods. MBBR is typically used for either high load industrial applications or for robust simple-to-operate municipal facilities.