MBBR and IFAS systems

Even though the moving bed biofilm reactor (MBBR)- and integrated fixed film activated sludge system (IFAS)-processes are designed and used more or less as they were from the beginning (in the 1990s), there have been several advances. This chapter focuses on advances that have been made during the last 10 years in biochemical oxygen demand (BOD)- and nutrient removal, and particularly in the use of MBBR-based processes for nitrogen removal by de-ammonification, MBBRs for biological phosphate removal and MBBR-based membrane bioreactors (MBRs). Advances in MBBR biomass separation including the use of dissolved air flotation, micro-sand ballasted lamella settling (ACTIFLO®) and micro-screening (disc filtration) are presented. MBBR-based membrane bioreactors (including MBBR MBR and IFAS MBR) are discussed and a comparison is carried out in terms of volumes and footprints of a pure MBBR plant, a conventional MBR plant (based on activated sludge) and an IFAS-based MBR plant