Abstract：
In recent years, the total nitrogen concentration in Taihu Lake has decreased significantly. Denitrification, as the main nitrogen removal process, is the key reason for the decrease. Here, the denitrification parameter values in the Environmental Fluid Dynamic Code (EFDC) model were calculated based on isotope-labeled denitrification experiment instead of selecting the recommended values directly. This study further focused on EFDC denitrification parameter derivation with an experimental denitrification rate (Dtot) to reduce simulation errors. According to the EFDC nitrate deposition flux mechanism, the conversion equation between the denitrification rate of the first sediment layer ([Formula: see text]) in EFDC and Dtot was successfully derived. The results revealed a linear correlation between [Formula: see text] and (Dtot)1/2. The [Formula: see text] values of sampling points ranged from 0.25 to 0.27 m·day-1, within the range of model parameters. After substituting [Formula: see text] into the Taihu Lake EFDC model, the average percentage bias and determination coefficient of total nitrogen were 16.25% and 0.87, respectively. The average total nitrogen concentration reduction caused by denitrification at water quality calibration points ranged from 0.027 to 0.305 mg·L-1.
摘要：
近年来,太湖总氮浓度显著下降。反硝化,作为主要的脱氮工艺,是下降的关键原因。这里,基于同位素标记的反硝化实验，而不是直接选择推荐值，计算了环境流体动力代码（EFDC）模型中的反硝化参数值。本研究进一步侧重于EFDC反硝化参数推导与实验反硝化速率（Dtot），以减少模拟误差。根据EFDC硝酸盐沉积通量机理，成功推导了EFDC中第一沉积物层的反硝化速率（[公式：见正文]）与Dtot之间的转换方程。结果揭示[公式:参见正文]与(Dtot)1/2之间的线性相关性。[公式:见正文]采样点的值范围为0.25~0.27m·day-1,在模型参数范围内。将[公式:见正文]代入太湖EFDC模型后,总氮的平均百分比偏差和测定系数分别为16.25％和0.87。在水质校准点，反硝化导致的总氮浓度平均降低范围为0.027~0.305mg·L-1。
