三峡库区重庆典型弯道段泥沙与氮磷污染物关系研究

发布时间：2018-05-06 23:05

  本文选题：三峡库区 + 弯道　； 参考：《重庆交通大学》2014年硕士论文

【摘要】：长江三峡工程是全世界瞩目的特大型水利水电枢纽工程，其建成后库区由河道转为水库，库区水位提升、水流减缓，水体自净能力也有所下降，，部分支流河段已经出现了富营养化现象。富营养化问题除与水流状态有关外，其水体氮、磷含量与泥沙状况是其最主要的影响因素，而由于三峡库区水文情况的变化，弯道段泥沙的淤积情况更为严重。因此进行三峡库区重庆典型弯道段泥沙与氮、磷污染物的关系研究对防治长江流域的水体富营养化具有重要的理论意义与现实价值。 本文在分析三峡库区重庆段主要断面多年水沙监测数据的基础上，采用理论分析、现场监测和室内实验相结合的方法对三峡库区重庆典型弯道段泥沙与氮、磷污染物关系进行了研究，获得的主要研究结果如下：三峡库区重庆段输沙量和泥沙的淤积往往集中在汛期，且弯道段泥沙的淤积情况更为严重，同时汛期库区重庆段存在氮、磷污染；三峡库区重庆典型弯道段—皇华城水域的水中泥沙以细颗粒泥沙为主，其中D≤0.025mm的泥沙以重量计占总重的72%~90%；泥沙含量是决定天然水体氮、磷含量的一个主要因素。该区域泥沙对天然水体磷含量的贡献率为56.2%~64.4%；泥沙对天然水体总氮含量的贡献率为62.1%~68.7%，对氨氮含量的贡献率为54%~67%，对硝态氮的贡献率为51%~78%。室内机理试验中得知，小粒径的泥沙相对于较大粒径泥沙对氮、磷污染物的吸附量大；泥沙吸附氮、磷的吸附量随泥沙浓度增大而增加，吸附量随污染物浓度增加而增大；酸碱性对泥沙吸附氮、磷污染物有影响，pH在3～11变化时，泥沙对氮磷的吸附量基本上均呈“U”型变化，泥沙对氮磷的吸附量在pH为7时均最小；当振荡速率为120r/min～720r/min时，吸附量为0.11mg/g～0.18mg/g，随振荡速率增大而增加，泥沙对磷的吸附量与振荡速率有较好的正相关性；泥沙对磷的解吸量随泥沙粒径的增大而减小，且0h～11h为主要解吸时段，11h～48h为极慢速解吸时段，11h时，泥沙浓度为0.2kg/m3～1.5kg/m3时，磷的解吸量为0.213mg/g～0.277mg/g，说明泥沙对磷的解吸量是随着泥沙浓度的增加而减小。 本文研究可以为三峡库区水体氮、磷污染防治与长江水资源保护提供重要的科学依据。
[Abstract]:The three Gorges Project of the Yangtze River is an extremely large water conservancy and hydropower hub project that has attracted worldwide attention. After its completion, the reservoir area has changed from a river to a reservoir. The water level in the reservoir area has risen, the water flow has slowed down, and the self-purification capacity of the water has Eutrophication has occurred in some tributaries. The eutrophication problem is not only related to the flow state, but also the nitrogen, phosphorus content and sediment condition are the most important influencing factors. Because of the change of the hydrological situation in the three Gorges Reservoir area, the sediment deposition in the bend section is more serious. Therefore, it is of great theoretical and practical value to study the relationship between sediment and nitrogen and phosphorus pollutants in typical bend sections of the three Gorges Reservoir area in order to prevent eutrophication in the Yangtze River basin. On the basis of analyzing the monitoring data of water and sediment in the main sections of Chongqing section of the three Gorges Reservoir area, the paper uses the method of theoretical analysis, field monitoring and laboratory experiment to study the sediment and nitrogen in typical bend section of Chongqing reservoir area. The main results obtained are as follows: sediment transport and sediment deposition in Chongqing section of the three Gorges Reservoir area are usually concentrated in flood season, and the sediment deposition in bend section is more serious, and nitrogen exists in Chongqing section of reservoir area during flood season. Phosphorus pollution; sediment in water of typical bend section of Chongqing-Huanghua city in the three Gorges Reservoir area is dominated by fine grain sediment, in which D 鈮

本文编号：1854285