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Floc management enables integrated anammox and enhanced biological phosphorus removal for sustainable ultra-efficient nutrient removal

Nature Water volume 3, pages 201–210 (2025)Cite this article

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Abstract

Nutrient removal from wastewater is crucial for global wastewater recycling and sustainable reuse. However, traditional methods for nitrogen and phosphorus removal face limitations in terms of energy consumption, operational complexity and environmental impact. Here we develop a floc management strategy to integrate anammox and enhanced biological phosphorus removal (EBPR) processes in a single-stage hybrid system (biofilms and flocs). This integrated approach resolves the conflicts between anammox and EBPR processes concerning ecological niche and solid retention time, enabling ultraefficient nitrogen and phosphorus removal efficiencies of 97.7 ± 1.3% and 97.4 ± 0.7%, respectively, in low-carbon municipal wastewater treatment. Notably, anammox benefitted from substrate competition with endogenous denitrification (both nitrite and nitrate) with floc loss, resulting in a significant enrichment of anammox bacteria in biofilms (12.5%) under mainstream conditions. Meanwhile, controlling floc concentrations at around 1,000 mg l−1 could maintain low polyphosphate levels in flocs, effectively addressing the additional phosphorus removal burden imposed by the enrichment of phosphorus-accumulating organisms in biofilms. This work offers a transformative solution to the long-standing challenge of integrating anammox and EBPR, paving the way for more sustainable and energy-efficient nutrient removal in wastewater treatment.

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Fig. 1: Long-term performance of the SNPR process during 500 days of operation.
Fig. 2: Profiles of nitrogen species concentrations during the anoxic phase under different periods.
Fig. 3: Evolution of anammox activity and abundance.
Fig. 4: Long-term dynamics and visualization of poly-P in flocs and biofilms.
Fig. 5: Microbial community characterization in flocs and biofilms.
Fig. 6: Representative FISH–CLSM digital images illustrating the distribution of AnAOB (red), AOB-amoA (blue) and NOB Nitrospira (green) in biofilms.

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Data availability

The data generated in this study are provided within the article and its Supplementary Information. Raw sequencing data have been archived in NCBI Sequence Read Archive with the accession number SRR27602558-27602564. Source data are provided with this paper.

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Acknowledgements

This work was financially supported by Key Program of National Natural Science Foundation of China (52131004, Y.P.), Biological Wastewater Treatment and Process Control Technology, Beijing International Science and Technology Cooperation Base (Y.P.), and the Funding Projects of Beijing Municipal Commission of Education (Y.P.).

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Authors and Affiliations

  1. National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing, P. R. China

    Qiongpeng Dan, Qiong Zhang, Tong Wang, Hanbin Wang & Yongzhen Peng

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  1. Qiongpeng Dan
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  2. Qiong Zhang
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  3. Tong Wang
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  4. Hanbin Wang
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  5. Yongzhen Peng
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Contributions

Q.D., T.W. and Y.P. conceived the idea and designed the experiments. Q.D., Q.Z., T.W. and H.W. conducted the experiments, and collected and analysed the data. Q.D. and T.W. prepared the figures, and wrote the paper and supplementary information. Q.Z. and Y.P. supervised the work. All the authors discussed the results and commented on the paper.

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Correspondence to Yongzhen Peng.

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Dan, Q., Zhang, Q., Wang, T. et al. Floc management enables integrated anammox and enhanced biological phosphorus removal for sustainable ultra-efficient nutrient removal. Nat Water 3, 201–210 (2025). https://doi.org/10.1038/s44221-024-00380-w

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