大沽河河床渗滤过程中氨氮的迁移—转化规律研究

发布时间：2018-04-28 13:55

  本文选题：河床渗滤 + 氨氮　； 参考：《中国海洋大学》2015年硕士论文

【摘要】：污染河水在补给周围地下水的过程中,地下水是否会受到污染及污染程度的高低取决于河床渗滤系统。氨氮作为水体中最主要的氮污染物，有着诸多危害。受氨氮污染的地表水体也有可能引起地下水的氨氮污染,造成地下水水质恶化。本文在野外调查和采样的基础上,用大沽河底泥和砂土进行了氨氮吸附和转化的批量试验研究以及氨氮在模拟河床渗滤系统中迁移转化的柱试验研究。研究结果可为控制氨氮污染河水在补给过程中污染地下水提供理论依据和技术支持。在氨氮的吸附试验中,分别研究了温度、pH、水流扰动对两种渗滤介质吸附氨氮的影响；在氨氮的转化试验中,分别研究了温度和pH对转化过程的影响：在模拟渗滤试验中,研究了渗滤系统的水动力学参数、阻滞系数和氨氮在其中所发生的实际迁移转化行为。氨氮吸附的动力学试验的试验结果表明,两种渗滤介质对氨氮的吸附可划分成快速吸附阶段和慢速吸附阶段：两种介质均在pH为中性时对氨氮具有较大的吸附速率；随着温度的增加,两种介质对氨氮的平衡吸附量减少,底泥的吸附速率常数在25℃时最大,砂土的吸附速率常数是随着温度的而增加而减小的；扰动强度的增大加大了两种渗滤介质对氨氮的吸附速率,但是对平衡吸附量影响不大。氨氮吸附的热力学试验结果表明,两种渗滤介质对氨氮的吸附等温线呈现出线性变化趋势：两种介质的吸附分配系数均随温度的升高而降低,但在氨氮平衡浓度较低时,二者的平衡吸附量随温度变化差别不大：底泥的分配系数比砂土的高一个数量级；两种介质的吸附热力学行为随pH的变化呈现出相似的变化趋势。氨氮的转化试验结果表明,硝化作用是底泥转化氨氮的主要过程。在试验温度区间(10℃-30℃)内,氨氮的硝化速率随温度的升高而增大。试验中求得速率常数与温度的关系为K=0.082×1.170T-20(d-1)。在试验pH区间(6-8)内,氨氮的硝化速率随pH的升高而增大。在柱试验中,通过水动力学弥散试验计算得到砂土的渗透系数、弥散系数、弥散度、有效孔隙度分别为29.5 m/d、0.108 m2/d、4.05×10-3m和34.7%,底泥的上述参数分别为0.471 m/d、 7.10×10-3m2/d、3.06×10-3m和40.5%；砂土和底泥对氨氮的阻滞系数分别为2.47和8.36；而模拟一维渗滤试验表明渗滤系统去除氨氮主要是通过底泥的吸附和硝化作用及砂土的吸附作用；在溶解氧降低时,底泥中也会发生一定程度的反硝化作用;渗滤系统对氨氮的去除是有一定限度的。
[Abstract]:Whether the polluted river water will be polluted or not depends on the percolation system in the process of recharging the surrounding groundwater. As the main nitrogen pollutant in water, ammonia nitrogen has a lot of harm. Surface water bodies polluted by ammonia nitrogen may also cause ammonia nitrogen pollution of groundwater and lead to the deterioration of groundwater quality. On the basis of field investigation and sampling, the batch experiments of ammonia nitrogen adsorption and transformation were carried out by using the bottom mud and sandy soil of Dagu River, and the column test of ammonia nitrogen migration and transformation in simulated riverbed leachate system was carried out. The results can provide theoretical basis and technical support for controlling the pollution of groundwater in the process of recharge of river water polluted by ammonia nitrogen. In the ammonia nitrogen adsorption experiment, the effects of temperature and pH and the disturbance of water flow on the adsorption of ammonia nitrogen were studied, and the effects of temperature and pH on the conversion process of ammonia nitrogen were studied in the experiment of ammonia nitrogen conversion. The hydrodynamic parameters, block coefficient and the actual transport and transformation behavior of ammonia nitrogen in the percolation system were studied. The results of kinetic experiments on the adsorption of ammonia nitrogen showed that the adsorption of ammonia nitrogen by two kinds of leachate media could be divided into two stages: fast adsorption stage and slow adsorption stage: the adsorption rate of ammonia nitrogen was higher when pH was neutral; With the increase of temperature, the equilibrium adsorption capacity of ammonia and nitrogen decreases, the adsorption rate constant of sediment is maximum at 25 鈩，

本文编号：1815549