Deng Li-Fan, Huang Ting-Lin, Li Nan, Li Kai, Lü Xiao-Long, Mao Xue-Jing
Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University Architecture and Technology, Xi'an 710055, China.
Huan Jing Ke Xue. 2019 Jun 8;40(6):2722-2729. doi: 10.13227/j.hjkx.201810199.
In view of the problem of excessive manganese concentrations in the Xi'an Jinpen Reservoir during the flood season in 2017, the vertical distribution of manganese in density currents and its occurrence pattern were monitored at multiple monitoring sections along the upstream reaches to the main basin. The influences of density currents plunging into the reservoir on the migration and transformation of Mn were studied, and sedimentation, output, and deposition of manganese in the reservoir water were also specifically estimated during a single, typical storm runoff process. Devices for avoiding high turbidity and high load inflows in rainfall events were proposed. The results showed that significant increases of total manganese were induced by high-turbidity inflows, which largely degraded water quality during rainfall events. From 12 to 14 October, 9.11 tons of total manganese were transported into the reservoir during a single rainfall event, and the pollution conditions were largely remitted by flood discharges with an output of 6.22 tons; thus, the net deposition (manganese) was 1.47 tons. The manganese content and morphological changes along the upper reaches of the reservoir indicated that soil erosion occurred during the continuous rainfall process, and this caused a large amount of particulate pollutants to flow into the water body with the runoff. More than 70% of the total manganese in the water was in the iron-manganese oxide bound state. Correlation analysis was conducted with particles of different particle size ranges, and granular manganese particle sizes were about 2-20 μm. The findings indicate that when flood discharges with turbidity currents occur, this can effectively reduce the load of pollutants and the safety risks of water.
针对2017年汛期西安金盆水库锰含量超标问题，对水库上游至主库区多个监测断面密度流中锰的垂向分布及其赋存形态进行了监测。研究了密度流潜入水库对锰迁移转化的影响，并针对单次典型暴雨径流过程，具体估算了水库水体中锰的沉降、输出及沉积情况。提出了降雨事件中避免高浊度、高负荷入库的措施。结果表明，高浊度入库导致总锰显著增加，在降雨期间大幅降低了水质。10月12日至14日，单次降雨事件期间有9.11吨总锰输入水库，通过6.22吨的泄洪，污染状况基本得到缓解；因此，锰的净沉积量为1.47吨。水库上游锰含量及形态变化表明，连续降雨过程中发生了土壤侵蚀，导致大量颗粒污染物随径流流入水体。水体中总锰的70%以上处于铁锰氧化物结合态。对不同粒径范围的颗粒进行了相关性分析，颗粒态锰粒径约为2 - 20μm。研究结果表明，当出现含浊流的泄洪时，可有效降低污染物负荷及水体安全风险。
