Recent Progress of NOB Control Strategies in Sewage PN/A Process

Single-stage partial nitritation and anammox (PN/A) process is one of the research hotspots in sewage nitrogen removal technologies since it has several advantages such as low aeration consumption and no need of organic carbon. For actual application of sewage single-stage PN/A process, stable operation is critical but highly affected by NOB proliferation. The overgrowth of NOB causes the increase of effluent nitrate concentration and compete out functional microorganisms for nitrogen removal, thereby seriously destroying nitrogen removal performance. The research progress of NOB control strategies in sewage single-stage PN/A process was reviewed. In particular, critical strategies including selective inhibitory substrate addition, selective biomass discharge and bio-augmentation were highlighted, and their effects and mechanisms were discussed. For future studies aiming at NOB control in sewage PN/A process, the combination of multiple inhibitory strategies and underlying microbial mechanism were suggested. In addition, developing novel combined process to reduce negative effects of NOB proliferation on nitrogen removal performance is also a feasible research direction.