Mixotrophic S-Anammox Enrichment for Synergistic Nitrogen and Sulfur Removal: Performance, Microbial Community Succession, and Key Functional Taxa

DOI: https://doi.org/10.62517/jlsa.202607203

Author(s)

Fangyuan Ren, Li Cui*, Siqi Gang

Affiliation(s)

School of Environmental and Chemical Engineering, Shenyang University of Technology, Shenyang, China *Corresponding Author

Abstract

The S-Anammox process couples sulfur (S) and nitrogen (N) cycling in anaerobic environments, yet its metabolic behavior under mixotrophic conditions remains largely unexplored. This study examines the operational performance and microbial community succession in a laboratory-scale UASB bioreactor during a 180-day period of mixotrophic S-Anammox enrichment under intermittent organic carbon (COD) addition. Our results demonstrate that intermittent COD supply significantly enhances sulfate reduction efficiency up to 46.5% (average 32.8%) while preserving robust ammonium removal. 16S rRNA amplicon sequencing revealed a distinct microbial community restructuring under mixotrophic conditions: the anammox genus Candidatus_Brocadia was substantially enriched, while nitrite-oxidizing Nitrospira nearly disappeared, effectively suppressing nitrate accumulation. Concurrently, denitrifying Denitratisoma and sulfate-reducing Thermodesulfobacteriota were stably maintained, establishing a functional consortium for coordinated N-S removal. These findings provide new insights into the mixotrophic S-Anammox process, demonstrating that intermittent COD addition fosters a synergistic autotrophic-heterotrophic system successfully. This strategy effectively overcomes the limitations of purely inorganic or organic conditions, offering a promising technical pathway for treating industrial wastewater containing both ammonium, sulfate and COD in the wastewater.

Keywords

S-Anammox; Mixotrophic Condition; Microbial Community Succession; Nitrogen Removal; Sulfate Reduction

References

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