间歇曝气实现上覆水脱氮及氨氮的荧光法表征

为实现河流上覆水有效脱氮及快速表征氨氮的变化,采用间歇曝气研究二十埠河上覆水中氮的转化规律及去除效果,并结合三维荧光技术研究DOM(溶解性有机物)荧光强度与氨氮浓度的关系.工况运行结果表明:间歇曝气实现了上覆水的硝化反硝化脱氮,氨氮在硝化阶段呈现明显下降趋势,在反硝化阶段则呈现明显上升趋势;硝酸盐氮和亚硝酸盐氮在硝化阶段呈现明显升高而在反硝化阶段呈现明显下降趋势,而总氮呈现一直下降趋势,随着DO(溶解氧)增加,氨氮和总氮去除效果均增加,当DO分别为3.5,4.5,5.5,6.5mg/L时,上覆水中总氮分别降为5.11,1.42,1.13,0.91mg/L,氨氮分别降为4.13,1.30,0.85,0.72mg/L;荧光强度变化表明:低激发波长类酪氨酸和类色氨酸荧光强度变化与氨氮变化均呈现相同趋势,在DO分别为3.5,4.5,5.5,6.5mg/L时,低激发波长类酪氨酸和类色氨酸荧光强度之和与氨氮具有良好的相关性,其相关系数分别为0.974、0.972、0.966、0.984;研究表明,可以通过上覆水中低激发波长类酪氨酸和类色氨酸的荧光强度快速预测氨氮浓度,并根据氨氮变化及时、灵活地控制间歇曝气工艺的运行,为受污染河流提供快速有效的治理技术和科学依据.

Nitrogen removal in overlying water by intermittent aeration and ammonia indirect measurement by fluorescence method

In order to realize effective nitrogen removal in the polluted rivers and rapidly measuring ammonia nitrogen changes, the nitrogen conversion and removal effect in the overlying water were researched with intermittent aeration. The study also investigated the correlation between DOM fluorescence intensity and ammonia nitrogen concentration by excitation-emission matrix spectroscopy. The process showed that intermittent aeration realized the repeated nitrification and denitrification in the overlying water. Ammonia nitrogen obviously decreased in the stage of nitrification and increased in the stage of denitrification, while nitrate nitrogen and nitrite nitrogen significantly increased in the stage of nitrification and decreased in the stage of denitrification, and total nitrogen always declined. The removal effect of ammonia nitrogen and total nitrogen increased along with increasing DO concentration, total nitrogen declined to 5.11, 1.42, 1.13, 0.91mg/L and ammonia nitrogen declined to 4.13, 1.30, 0.85, 0.72mg/L respectively when DO concentration was 3.5, 4.5, 5.5 and 6.5mg/L, respectively. The changes of fluorescence intensity indicated that the changes of low excitation wavelength tyrosine and tryptophan had the same trend with those of ammonia nitrogen. The sum of fluorescence intensity of the low excitation wavelength tyrosine and tryptophan showed a good linear correlation with ammonia nitrogen concentration with correlation coefficient 0.974, 0.972, 0.966, and 0.984 when DO concentration was 3.5, 4.5, 5.5 and 6.5mg/L, respectively. The study demonstrates that ammonia nitrogen concentration can be rapidly predicted by detecting the total fluorescence intensity of the low excitation wavelength tyrosine and tryptophan and the process of the intermittent aeration can be controlled flexibly and timely based on the changes of the ammonia nitrogen concentration, and then provides a quick and effective control technique and theoretical support for polluted river.