上覆水环境变化对底泥释氮强度影响模拟研究

    Simulation Study on Influence of Change of Overlying Water Environment on Nitrogen Release Intensity of Sediment

    • 摘要: 为阐明水库底泥上覆水温度、pH值、水动力、溶解氧等水环境条件发生变化对底泥释氮强度的影响,采集内蒙古锡林郭勒盟大河口水库底泥作为样品,设计4因素5水平单因素底泥释氮室内模拟试验。结果表明:(1)底泥释氮强度与温度呈正相关,25℃条件下底泥总氮释放强度为1 606.40 mg·m-2,是5℃条件下的1.9倍。偏酸或偏碱性环境条件均有利于底泥总氮释放,中性条件下底泥释氮强度最弱,与pH值的拟合曲线呈开口向上的抛物线。高强度扰动下(转速R为100 r·min-1)底泥释氮强度为1 469.5 mg·m-2,是静置条件下的2.1倍。在低溶解氧或缺氧条件下底泥释氮强度较大,好氧条件会抑制底泥氮释放。(2)环境因子与底泥释氮强度的多种线形函数回归拟合表明,底泥释氮强度与温度、pH值、水动力环境因素以二次函数曲线拟合最优,与溶解氧以三次函数曲线拟合最优。

       

      Abstract: To clarify the influence mechanism of reservoir sediment overlying water temperature, pH, dissolved oxygen, water dynamic water environment change on sediment nitrogen release intensity, sediment slobber samples were collected from Inner Mongolia Xilinguole League river reservoir and 4 factors and 5 levels of single factor release nitrogen simulation tests in chamber were designed. The results showed that:(1)the nitrogen release intensity of sediment was positively correlated with temperature. The total nitrogen release rate of sediment at 25℃ was 1 606.40 mg·m-2, which was 1.9 times of the total nitrogen release rate under the condition of 5℃. Under the condition of partial acid or partial alkalinity, the total nitrogen release of sediment was also favorable. Under the neutral condition, the nitrogen release intensity of sediment was the weakest, and the fitted curve of nitrogen release intensity with pH showed an upward parabola. Under high intensity disturbance (R=100 r·min-1), the nitrogen release intensity of sediment was 1 469.5 mg·m-2, which was 2.1 times of the nitrogen release intensity under the static condition. Under the condition of low dissolved oxygen concentration or anoxic condition, the nitrogen release intensity of sediment is greater, and aerobic condition will inhibit the release of nitrogen in sediment. (2) A variety of linear function of nitrogen release intensity of environmental factors and sediment regression showed that sediment nitrogen release intensity and temperature, pH and hydrodynamic environment factors were the optimal quadratic function curve fitting, and dissolved oxygen in cubic function optimal curve fitting.

       

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