模拟评价COD对PN/A工艺脱氮及菌群分布的影响

Model-based evaluation of the effect of COD on nitrogen removal and microbial community distribution in PN/A process

  • 摘要: 通过建立一维多种群生物膜数学模型,评价了有机物(COD)对短程硝化/厌氧氨氧化(PN/A)工艺脱氮性能及微生物群落的影响机制。模拟结果表明,进水COD浓度显著影响功能菌群空间分布:低进水COD(<50 mg/L)时氨氧化菌(AOB)主要富集于颗粒外层,而高进水COD(>150 mg/L)则导致异养菌(HET)成为优势菌群。研究进一步发现,适度提高进水碳氮比可拓宽最佳溶解氧操作窗口,同时通过强化反硝化途径使脱氮贡献率提升20-30%,系统总氮去除率可稳定维持在85%以上。通过改进模型的计量矩阵,实现了对不同代谢途径中氮氧化物转化的精准示踪。定量分析表明,厌氧氨氧化菌(AnAOB)高丰度区域与系统最佳脱氮性能(总氮去除率>80%)呈现显著空间相关性,证实厌氧氨氧化过程仍是PN/A系统的核心脱氮途径。本研究为PN/A工艺运行参数的优化调控提供了重要的理论依据,特别是阐明了通过进水COD与DO浓度的协同调控实现工艺高效稳定运行的作用机制。

     

    Abstract:
    A one-dimensional multi-population biofilm mathematical model was developed to evaluate the mechanisms by which chemical oxygen demand (COD) influences nitrogen removal performance and microbial community in partial nitrification/anammox (PN/A) process. Simulation results demonstrated that influent COD concentration significantly affected the spatial distribution of functional microorganisms: under low COD conditions (<50 mg/L), ammonia oxidizing bacteria (AOB) predominantly colonized the outer layer of granules, while high COD levels (>150 mg/L) promoted heterotrophic bacteria (HET) as the dominant population. The study further revealed that moderately increasing the influent C/N ratio expanded the optimal dissolved oxygen (DO) operational window and enhanced the nitrogen removal contribution of denitrification by 20–30%, enabling stable total nitrogen removal efficiency exceeding 85%. By refining the stoichiometric matrix of the model, precise tracking of nitrogen oxide transformations across different metabolic pathways was achieved. Quantitative analysis confirmed strong spatial correlation between high-activity zones of anaerobic ammonium oxidation bacteria (AnAOB) and peak system performance (total nitrogen removal >80%), validating anammox as the core nitrogen removal pathway. This study provides critical theoretical guidance for optimizing PN/A process parameters, particularly elucidating the synergistic regulatory mechanism of influent COD and DO concentrations for achieving stable and efficient operation.

     

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