Progress in microbial ecology of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria in partial nitrification systems for wastewater treatment

Abstract:

Partial nitrification (PN) is a novel low-carbon technology for biological nitrogen removal from wastewater. With the application of anaerobic ammonia oxidation (anammox), PN, as the essential electron acceptor (i.e., NO₂^-) supplier for anammox, has become a hot topic in the field of wastewater nitrogen removal. Ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) are the two key groups of microorganisms involved in PN. To achieve a stable and efficient PN process, we need to clarify the microbial ecology of AOB and NOB for the washout of NOB and regulation of AOB and strengthen the predictability of microbial community. From the viewpoint of microbial ecology, this review introduced the taxonomic status, physiological properties, and niche separation of AOB and NOB, and highlighted the growth kinetics, community assembly, environmental factors, and mutual interactions of AOB and NOB in the PN process. Finally, we propose the future research directions involving the two groups of microorganisms, aiming to provide theoretical guidance for the rapid start-up and stable operation of the PN process.