Ultra-high nitrogen removal from real municipal wastewater using selective enhancement of glycogen accumulating organisms (GAOs) in a partial nitrification-anammox (PNA) system

• Published in: Water research (Oxford) 2023-02, Vol.230, p.119594-119594, Article 119594
• Main Authors: Wang, Hanbin, Zhang, Liang, Dan, Qiongpeng, Zhang, Yingxin, Wang, Shuying, Zhang, Qiong, Li, Xiyao, Wang, Chuanxin, Peng, Yongzhen
• Format: Article
• Language: English
• Subjects: Anaerobic Ammonia Oxidation; Bacteria - metabolism; Bioreactors - microbiology; Denitrification; Endogenous denitrification; Glycogen - metabolism; Glycogen-accumulating organisms; Mainstream anammox; Municipal wastewater; Nitrification; Nitrogen - metabolism; Oxidation-Reduction; Phosphorus - metabolism; Phosphorus-accumulating organisms; Sewage - microbiology; Wastewater
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2023.119594

•Excellent NRE of 97.5% was achieved with TIN below 2.0mg/L by selective enhanced GAOs.•Intermittent phosphorus exclusion with poly-P/VSS below 0.01(w/w) enhanced GAOs.•GAOs gained organics outcompeting PAOs at low poly-P and strengthened ED.•PNA was unaffected by the enhanced ED and coupled to remove nitrogen in the anoxic stage.•EPDA was promoted by the enrichment of GAOs that reduced NO3− to NO2− exclusively. Integrating endogenous denitrification (ED) into partial nitrification-anammox (PNA) systems by adequately utilizing organics in municipal wastewater is a promising approach to improve nitrogen removal efficiency (NRE). In this study, a novel strategy to inhibit phosphorus-accumulating organisms (PAOs) by inducing phosphorus release and exclusion was adopted intermittently, optimizing organics allocation between PAOs and glycogen-accumulating organisms (GAOs). Enhanced ED-synergized anammox was established to treat real municipal wastewater, achieving an NRE of 97.5±2.2% and effluent total inorganic nitrogen (TIN) of less than 2.0 mg/L. With low poly-phosphorus (poly-P) levels (poly-P/VSS below 0.01 (w/w)), glycogen accumulating metabolism (GAM) acquired organics exceeded that of phosphorus accumulating metabolism (PAM) and dominated endogenous metabolism. Ca. Competibacter (GAO) dominated the community following phosphorus-rich supernatant exclusion, with abundance increasing from 3.4% to 5.7%, accompanied by enhanced ED capacity (0.2 to 1.4 mg N/g VSS /h). The enriched subgroups (GB4, GB5) of Ca. Competibcater established a consistent nitrate cycle with anammox bacteria (AnAOB) through endogenous partial denitrification (EPD) at a ∆NO2−-N/∆NH4+-N of 0.91±0.11, guaranteeing the maintenance of AnAOB abundance and performance. These results provide new insights into the flexibility of PNA for the energy-efficient treatment of low-strength ammonium wastewater. [Display omitted]