MABRs, MBRs and MBBRs
The processes of membrane-aerated biofilm reactor (MABR), moving-bed bioreactor (MBBR), and membrane bioreactor (MBR) represent three distinctly different biological treatment technologies.
Two of the processes (the MABR and MBBR) are fixed-film in configuration, whereas the MBR is a modified activated sludge (or suspended growth) process. Since only the MBR provides membrane separation of the water from the solids, it’s also the only one of the three able to provide substantial disinfection and complete clarification. Against this, the MBR is generally higher in energy consumption and more complex in operation because of the requirement to control permeation through the membrane.
Of the two fixed-film processes, the MBBR is the simpler, being based on relatively inexpensive suspended plastic media particles on which the biofilm grows. The oxygen for maintaining the biofilm is provided by air bubbles generated by conventional fine-bubble diffusers. In the case of the MABR, the biofilm grows on the membrane, and the oxygen is fed directly into the biofilm in ‘bubbleless’ molecular form via the membrane.
The characteristics and applications of the three different processes are given below.
|MABR||Membrane aerated-biofilm reactor||Fixed film||Intensive (low-footprint) biological treatment using a membrane both as the biofilm substrate and for molecular (‘bubbleless’) aeration|
|MBBR||Moving bed bioreactor||Fixed film||Controllable biological treatment at relatively low energy demand using agitated media as the biofilm substrate|
|MBR||Membrane bioreactor||Suspended growth||Intensive (low-footprint) biological treatment using a membrane for clarification and substantial disinfection|