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Abstract <p>High levels of total nitrogen (TN) in urban rivers remain a significant environmental concern due to their contribution to malodor, which needs an urgent solution. Considering the critical role of sulfur (S) in river habitats, how and to what extent S is involved in nitrogen (N) transformation deserves attention, especially in the context of river remediations. In this study, sediment incubation and river simulation showed that denitrification had a higher tolerance to sulfide than anaerobic ammonium oxidation (anammox) and outcompeted anammox in substrate competition. Moreover, appropriate levels of sulfide (40&#xa0;mg·L<sup>−1</sup>) stimulated S-driven autotrophic denitrification (SAD) activity (from 0.010 to 0.021&#xa0;meq·g<sup>−1</sup> VSS·h<sup>−1</sup>), with the relative abundances of <i>Thiobacillus</i>-like bacteria increasing from 0.46% to 21.51%. However, 40&#xa0;mg·L<sup>−1</sup> sulfide inhibited anammox activity (from 0.010 to 0.0032&#xa0;meq·g<sup>−1</sup> VSS·h<sup>−1</sup>), with the decrease in both ammonium removal (from 55.25% to 22.32%) and anammox bacteria abundance (from 0.45% to 0.18%) in the incubation. A significant correlation (<i>P</i> &lt; 0.01) between TN and sulfate was observed in calcium nitrate added and aerated river simulations, which indicated that sulfide was involved in the N-transformation through SAD. This finding was further confirmed by the relatively high abundances of <i>Thiobacillus</i> (1.15% and 1.12%, respectively) in both sediment aeration and calcium nitrate addition systems. Notably, S-driven autotrophic partial denitrification coupled with anammox was discovered under calcium nitrate addition. This study can fill the gap in understanding the interactions of S and N biogeochemical processes with river remediations and can help establish an effective approach for TN removal.</p> Key points <p>• <i>Anammox showed higher sensitivity to 40&#xa0;mg·L</i><sup><i>−1</i></sup><i> sulfide than denitrification.</i></p> <p>• <i>Coupling mechanisms between S and N were studied based on real river scenario.</i></p> <p>• <i>Calcium nitrate induced the coupling of SAPD with anammox.</i></p> <p>• <i>Denitrification showed relatively high tolerance to sulfide in malodorous rivers.</i></p>

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Effects of sulfur on nitrogen transformation in malodorous rivers with different remediations

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年10月25日

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  • Yunyi Zha,
  • Chenxi Yu,
  • Yao Huang,
  • Jin Zhu,
  • Gongming Zhou,
  • Yan He

摘要

Abstract

High levels of total nitrogen (TN) in urban rivers remain a significant environmental concern due to their contribution to malodor, which needs an urgent solution. Considering the critical role of sulfur (S) in river habitats, how and to what extent S is involved in nitrogen (N) transformation deserves attention, especially in the context of river remediations. In this study, sediment incubation and river simulation showed that denitrification had a higher tolerance to sulfide than anaerobic ammonium oxidation (anammox) and outcompeted anammox in substrate competition. Moreover, appropriate levels of sulfide (40 mg·L−1) stimulated S-driven autotrophic denitrification (SAD) activity (from 0.010 to 0.021 meq·g−1 VSS·h−1), with the relative abundances of Thiobacillus-like bacteria increasing from 0.46% to 21.51%. However, 40 mg·L−1 sulfide inhibited anammox activity (from 0.010 to 0.0032 meq·g−1 VSS·h−1), with the decrease in both ammonium removal (from 55.25% to 22.32%) and anammox bacteria abundance (from 0.45% to 0.18%) in the incubation. A significant correlation (P < 0.01) between TN and sulfate was observed in calcium nitrate added and aerated river simulations, which indicated that sulfide was involved in the N-transformation through SAD. This finding was further confirmed by the relatively high abundances of Thiobacillus (1.15% and 1.12%, respectively) in both sediment aeration and calcium nitrate addition systems. Notably, S-driven autotrophic partial denitrification coupled with anammox was discovered under calcium nitrate addition. This study can fill the gap in understanding the interactions of S and N biogeochemical processes with river remediations and can help establish an effective approach for TN removal.

Key points

• Anammox showed higher sensitivity to 40 mg·L−1 sulfide than denitrification.

• Coupling mechanisms between S and N were studied based on real river scenario.

• Calcium nitrate induced the coupling of SAPD with anammox.

• Denitrification showed relatively high tolerance to sulfide in malodorous rivers.