The complex interaction between nitrate (NO) reduction and fermentation is poorly understood when high levels of NO are introduced into anaerobic systems. This study investigated the competitive distribution between conventional denitrification (DEN) and dissimilatory nitrate reduction to ammonium (DNRA) during simultaneous denitrification and fermentation in arrested methanogenesis. Up to 62% of initial NO (200 mg-N/L) was retained as ammonium through DNRA at a chemical oxygen demand (COD)/N ratio of 25. Significant NO emission occurred (1.7 – 8.0% of the initial NO) with limited carbon supply (≤1600 mg COD/L) and sludge concentration (≤3000 mg COD/L). VFA composition shifted predominantly towards acetic acid (>50%) in the presence of nitrate. A novel kinetic model was developed to predict DNRA vs. DEN partitioning and NO accumulation. Overall, NO input, organic loading, and carbon source characteristics independently and collectively controlled competitive DNRA vs. DEN partitioning.

中文翻译：

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产甲烷停滞期间反硝化途径的竞争性分配：对铵回收、N2O 排放和挥发性​​脂肪酸生产的影响

当将高水平的 NO 引入厌氧系统时，人们对硝酸盐 (NO) 还原和发酵之间复杂的相互作用知之甚少。本研究调查了在阻滞产甲烷过程中同时反硝化和发酵过程中常规反硝化 (DEN) 和异化硝酸盐还原成铵 (DNRA) 之间的竞争分布。在化学需氧量 (COD)/N 比为 25 时，高达 62% 的初始 NO (200 mg-N/L) 通过 DNRA 以铵形式保留。发生了显着的 NO 排放（初始 NO 的 1.7 – 8.0%）限制碳供应（≤1600 mg COD/L）和污泥浓度（≤3000 mg COD/L）。在硝酸盐存在下，VFA 组成主要转向乙酸 (>50%)。开发了一种新的动力学模型来预测 DNRA 与 DEN 分配和 NO 积累。总体而言，NO 输入、有机负荷和碳源特性独立和共同控制竞争性 DNRA 与 DEN 分配。