Scholarlink

<p>This study redefines bioretention systems (BRSs) by elucidating how saturated zone (SZ) depths (0‒480&#xa0;mm) and antecedent dry days (ADDs: 0.5‒4&#xa0;days) orchestrate microbial-driven nitrogen removal without organic carbon supplementation. Through lab-scale experiments with <i>Pennisetum alopecuroides</i>, we demonstrate that optimized hydrologic-microbial synergy shifts nitrogen elimination from passive filtration to a self-sustaining redox interface. Critically, coupling deeper SZs (&gt; 320&#xa0;mm) with moderate dry–wet cycles (&gt; 3-day ADDs) activated autotrophic denitrification via <i>Saccharibacteria</i> and <i>Bradyrhizobium</i>, reducing NO<sub>3</sub><sup>−</sup>–N accumulation to 7.59 ± 0.29&#xa0;mg/L (31.7% removal) while achieving stable NH<sub>4</sub><sup>+</sup>–N removal (&gt; 61.4‒68.8%) across conditions. In contrast, shallow SZs (&lt; 160&#xa0;mm) disrupted microbial cooperation, favoring incomplete nitrification and nitrate leakage. Proteobacteria dominated functional guilds in optimal SZ scenarios (e.g., 480&#xa0;mm SZ with 4 ADDs), where total inorganic nitrogen removal surpassed non-saturated systems by 25‒30%, proving carbon-independent pathways. The highest NH<sub>4</sub><sup>+</sup>–N removal (68.8 ± 1.5%) occurred at 160&#xa0;mm SZ with 2 ADDs, yet sustained efficiency required hydrologic thresholds that stabilized redox gradients. Microbial networks revealed deterministic assembly of nitrifier-denitrifier consortia under controlled hydrology, contrasting the stochasticity in suboptimal designs. These insights establish SZ-ADD-microbe codependencies as a design cornerstone, replacing ad hoc filtration metrics. By prioritizing microbial niche differentiation over soil adsorption, this work resolves the paradox of nitrate pollution in carbon-limited stormwater, offering a mechanistic blueprint for adaptive, carbon–neutral BRSs—a critical advance for eutrophication mitigation.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Effectiveness of bioretention system with saturated zone and different dry–wet alterations on nitrogen removal: performance and microbial community

  • 期刊论文

  • 发表日期：

    2025年7月21日

查看全文
  • Ran Li,
  • Binyu Lu,
  • Wen-wen Liu,
  • Zebing Li,
  • Yi-Ming Kuo

摘要

This study redefines bioretention systems (BRSs) by elucidating how saturated zone (SZ) depths (0‒480 mm) and antecedent dry days (ADDs: 0.5‒4 days) orchestrate microbial-driven nitrogen removal without organic carbon supplementation. Through lab-scale experiments with Pennisetum alopecuroides, we demonstrate that optimized hydrologic-microbial synergy shifts nitrogen elimination from passive filtration to a self-sustaining redox interface. Critically, coupling deeper SZs (> 320 mm) with moderate dry–wet cycles (> 3-day ADDs) activated autotrophic denitrification via Saccharibacteria and Bradyrhizobium, reducing NO3−–N accumulation to 7.59 ± 0.29 mg/L (31.7% removal) while achieving stable NH4+–N removal (> 61.4‒68.8%) across conditions. In contrast, shallow SZs (< 160 mm) disrupted microbial cooperation, favoring incomplete nitrification and nitrate leakage. Proteobacteria dominated functional guilds in optimal SZ scenarios (e.g., 480 mm SZ with 4 ADDs), where total inorganic nitrogen removal surpassed non-saturated systems by 25‒30%, proving carbon-independent pathways. The highest NH4+–N removal (68.8 ± 1.5%) occurred at 160 mm SZ with 2 ADDs, yet sustained efficiency required hydrologic thresholds that stabilized redox gradients. Microbial networks revealed deterministic assembly of nitrifier-denitrifier consortia under controlled hydrology, contrasting the stochasticity in suboptimal designs. These insights establish SZ-ADD-microbe codependencies as a design cornerstone, replacing ad hoc filtration metrics. By prioritizing microbial niche differentiation over soil adsorption, this work resolves the paradox of nitrate pollution in carbon-limited stormwater, offering a mechanistic blueprint for adaptive, carbon–neutral BRSs—a critical advance for eutrophication mitigation.