An update on hybrid membrane aerated biofilm reactor technology

The hybrid membrane aerated biofilm reactor (MABR) process combines the advantages of the counter-diffusional biofilm and bubbleless aeration of the MABR with the good bioflocculation and carbon processing capabilities of suspended growth processes. These features result in a process with reduced physical footprint, excellent biological nutrient removal capabilities, potentially reduced greenhouse gas (GHG) emissions, and significantly reduced energy requirements that can be easily retrofitted into existing suspended growth processes. Commercially introduced in the mid-2010s, the demonstrated advantages of the hybrid MABR process are resulting in rapid full-scale adoption. Meanwhile, researchers are advancing knowledge on the hybrid MABR process and revealing potential opportunities for improved performance. This paper summarizes recent findings and identifies areas that can be further developed to advance hybrid MABR process evaluation and development. PRACTITIONER POINTS: Rapid application of the hybrid MABR process is leading to significant new developments that can enhance performance. Sizing MABR for nearly complete nitrification allows significant downsizing of the bioreactor, coupled with excellent nitrogen removal and energy savings. Online exhaust gas % O₂ and bulk ammonia concentration can be used to create a soft sensor characterizing changes in biofilm thickness enabling biofilm control to optimize performance. Further advancements through improved aeration control, configurations to achieve partial nitritation and annammox, and achieving granulation offer further significant advances.