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 do not need a recycling of the sludge, which is the case with activated sludge systems.
The MBBR system is often installed as a retrofit of existing activated sludge tanks to increase the capacity of the existing system. The degree of filling of carriers can be adapted to the specific situation and the desired capacity.  Thus an existing treatment plant can increase its capacity without increasing the footprint by constructing new tanks.
Some other advantages are:
* Increased performance and volumetric treatment capacity
* Higher effective sludge retention time (SRT) which is favorable for nitrification
* Responds to load fluctuations without operator intervention
* Lower sludge production
* Less area required
* Resilient to toxic shock
* Process performance independent of secondary clarifier (due to the fact that there is no sludge return line).