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Granule formation, microstructure and microbial spatial distribution are crucial to granule stability and nitrogen removal. Here, an upflow blanket filter (UBF) reactor with porous fixed cylinder carriers was fabricated and operated for 234 days to investigate overall performance and the formation mechanism of anammox granules. Results showed that the UBF performed the highest nitrogen removal efficiency of 93.19 ± 3.39% under nitrogen loading rate of 3.6 kg-N/m/d and HRT of 2 h. The tryptophan-like proteins as the key component in EPS were vital for granules formation. Further 16 s rRNA analysis indicated that SBR1031 with a relative abundance of 40.5% played an important role in cell aggregation. Thus, anammox granules were developed successfully with a two-layered spatial structure where outer-layer was ammonia oxidizing bacteria and inner-core was anaerobic ammonia oxidizing bacteria. Together, introduction of porous fixed cylinder carriers is a valid method to avoid biomass loss and floatation.
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http://dx.doi.org/10.1016/j.biortech.2022.128206 | DOI Listing |
Environ Res
August 2025
School of Hydraulic and Ocean Engineering, Changsha University of Science & Technology, Changsha, 410114, China; Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, 410114, China.
The single-stage partial nitritation-anammox (PNA) process is widely regarded as a sustainable strategy for nitrogen removal from high-strength ammonium wastewater, yet its stability remains challenged under elevated ammonium conditions. In this study, a lab-scale airlift inner-circulation reactor with a working volume of 1.9 L was continuously operated for 247 days to evaluate the synergistic effects of calcium ion addition on process performance, microbial structure, and gene expression.
View Article and Find Full Text PDFBioresour Technol
November 2025
School of Municipal and Environmental Engineering, Shenyang Jianzhu University, Shenyang 110168, China.
The Simultaneous Anammox and Denitrification (SAD) process effectively removes organic carbon sources, the impact of high-concentration carbon sources on the SAD process remains unclear. This study investigated the performance, sludge characteristics, microbial community correlations, and metagenomic sequencing of the SAD system under conditions of excessive organic matter exposure. The results showed that the organic matter metabolism ability of SAD granular sludge increased from 90.
View Article and Find Full Text PDFBioprocess Biosyst Eng
September 2025
State Key Laboratory of Advanced Environmental Technology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
The slow growth rate of anaerobic ammonium oxidation (anammox) bacteria and susceptibility of anammox sludge to washout pose significant challenges for the successful start-up and stable operation of the anammox process. Granulation may resolve this issue. This study investigated the effects of biotic and abiotic particle addition on the start-up and operation of anammox reactor by inoculating seed sludge with suspended, granular, magnesium ammonium phosphate (MAP) coupled anammox sludge, and pure MAP precipitates, aiming to promote granulation and preserve anammox functionality.
View Article and Find Full Text PDFBioresour Technol
October 2025
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. Ele
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.
View Article and Find Full Text PDFBioresour Technol
October 2025
Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, PR
This study explored the influencing mechanism for key parameters of hydraulic retention time (HRT) and upflow velocity on the anammox sludge blanket characteristics and functional microbial communities in an anammox expanded granular sludge bed. Shortening HRT from 8 h to 4 h improved nitrogen removal and expanded the effective working zone from 36.9 % to 60.
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