Efficient and stable removal of organic matter, nitrogen and phosphorus from swine manure digestate by coupling high-rate activated sludge and single-stage partial nitritation/anammox-hydroxyapatite processes

Yunzhi Qian; Shilong He; Yan Guo; Fuqiang Chen; Junhao Shen; Yu Qin; Yu-You Li

doi:10.1016/j.biortech.2025.132857

Efficient and stable removal of organic matter, nitrogen and phosphorus from swine manure digestate by coupling high-rate activated sludge and single-stage partial nitritation/anammox-hydroxyapatite processes

Bioresour Technol. 2025 Jun 19:434:132857. doi: 10.1016/j.biortech.2025.132857. Online ahead of print.

Authors

Yunzhi Qian¹, Shilong He², Yan Guo³, Fuqiang Chen⁴, Junhao Shen⁵, Yu Qin⁶, Yu-You Li⁷

Affiliations

¹ School of Environment and Spatial Informatics, China University of Mining & Technology, Xuzhou 221116, China; Graduate School of Environmental Studies, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
² School of Environment and Spatial Informatics, China University of Mining & Technology, Xuzhou 221116, China.
³ Department of Environmental Engineering, School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.
⁴ College of Science and Technology, Ningbo University, Ningbo 315300, China.
⁵ Graduate School of Environmental Studies, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
⁶ Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
⁷ Graduate School of Environmental Studies, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan; Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan. Electronic address: gyokuyu.ri.a5@tohoku.ac.jp.

PMID: 40543821
DOI: 10.1016/j.biortech.2025.132857

Abstract

Organic matter stress restricts the efficiency and broader applicability of anammox process for high-nutrient digestate treatment. A high-rate activated sludge (HRAS) process coupled a single-stage partial nitritation/anammox-hydroxyapatite (PN/A-HAP) process was developed to treat swine manure digestate. The coupled processes achieved stable removal efficiencies of 92 % (N), 63 % (P), and 66 % (chemical oxygen demand, COD), respectively. The HRAS process reduced the five-day biological oxygen demand/COD ratio to 0.31, effectively mitigating the organic stress of anammox process. The synergistic effect of HAP crystallization and external forces induced structural fragmentation of PN/A-HAP granules. The HAP microcrystals in fragmented sludge (<100 μm) function as nucleation cores, driving PN/A-HAP granules reformation. Ca. Kuenenia dominated in the PN/A-HAP microbial community and demonstrated a positive correlation with the saturation index of HAP. This study offers a significant reference for the implementation of the HRAS-PN/A HAP process aimed at achieving COD, N, and P removal.

Keywords: Anammox granulation; One-stage PNA; Organic stress; Phosphorus recovery; Swine wastewater.