A critical review of oxygen supply and control strategies in single-stage partial nitritation-anammox system for autotrophic nitrogen removal from wastewater

Abstract

The single-stage partial nitritation and anerobic ammonium oxidation (PN/A) process stands out as a sustainable and energy-efficient approach for nitrogen removal from wastewater. While oxygen is essential for the metabolic activities of ammonium oxidizing bacteria, yet its concentration must be delicately balanced. This critical review provides an in-depth analysis of oxygen supply and control approaches in single-stage PN/A systems, focus on methods such as intermittent aeration and continuous low-rate aeration. It examines the interactions between oxygen availability and the microbial communities, and evaluates the operational effectiveness and impact on system performance. The review also introduces several strategies that have been employed to optimize oxygen supply, identifies gaps in current knowledge regarding oxygen's role in the PN/A process and proposes future research directions to address these issues. These include a deeper understanding of microbial ecology under varying oxygen regimes, the development of advanced monitoring and control technologies for real-time optimization of oxygen levels, and the exploration of novel reactor designs to enhance oxygen utilization efficiency and microbial synergy. This review underscores the importance of developing oxygen supply strategies in PN/A systems and calls for further research to refine these strategies, thereby enhancing the process's energy efficiency and nitrogen removal performance. By addressing these challenges, the innovative strategies discussed in this review pave the way for the practical implementation of Anammox technology, offering a sustainable solution for wastewater nitrogen removal.