Towards advanced simultaneous nitrogen removal and phosphorus recovery from digestion effluent based on anammox-hydroxyapatite (HAP) process: Focusing on a solution perspective

• Published in: Bioresource Technology Vol. 381; p. 129117
• Main Authors: Cheng, Hui, Qin, Haojie, Liang, Lei, Li, Yu-You, Liu, Jianyong
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.08.2023; Elsevier BV
• Subjects: Advanced nitrogen removal; Anaerobic Ammonia Oxidation; anaerobic ammonium oxidation; Anaerobic fermentation; Anammox-hydroxyapatite; Bioreactors; Bioreactors - microbiology; Denitrification; Digestion; Digestion effluent; Durapatite; fermentation; inorganic carbon; Nitrogen; Oxidation-Reduction; Phosphorus; Phosphorus recovery; Sewage; sludge; Digestion effluent; Anaerobic fermentation; Phosphorus recovery; Advanced nitrogen removal; Anammox-hydroxyapatite
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2023.129117

[Display omitted] •The mechanism and significance of the anammox-HAP process are elucidated.•Anammox-HAP process cannot achieve the complete nitrogen removal.•Anammox-HAP process faces the problem of the impurities in the recovered HAP.•The AF-PD-anammox-HAP-combined novel process is proposed.•The advanced N removal and P recovery can be achieved by the proposed process. In this paper, the state-of-the-art information on the anammox-HAP process is summarized. The mechanism of this process is systematically expounded, the enhancement of anammox retention by HAP precipitation and the upgrade of phosphorus recovery by anammox process are clarified. However, this process still faces several challenges, especially how to deal with the ∼ 11% nitrogen residues and to purify the recovered HAP. For the first time, an anaerobic fermentation (AF) combined with partial denitrification (PD) and anammox-HAP (AF-PD-Anammox-HAP) process is proposed to overcome the challenges. By AF of the organic impurities of the anammox-HAP granular sludge, organic acid is produced to be used as carbon source for PD to remove the nitrogen residues. Simultaneously, pH of the solution drops, which promotes the dissolution of some inorganic purities such as CaCO3. In this way, not only the inorganic impurities are removed, but the inorganic carbon is supplied for anammox bacteria.