水库三维Fe、Mn迁移模型——阿哈水库实例研究

3 Dimensional Mathematical Model for the Transportation of Fe and Mn in Arha Reservoir

通过描述Ｆｅ、Ｍｎ在水库中的氧化还原变化、吸附、解吸、沉降及再悬浮，考虑水流运动对Ｆｅ、Ｍｎ迁移变化的影响，研制了水库三维水动力模式及三维Ｆｅ、Ｍｎ迁移变化模式，从而建立了完整的水库三维Ｆｅ、Ｍｎ迁移分布模拟模型。该模型在阿哈水库实际运用效果良好。模拟结果表明，水库水流运动整体流速较小，Ｆｅ、Ｍｎ在水库中平行迁移运动缓慢。进入水库的Ｆｅ、Ｍｎ负荷大量沉入库底，在水体缺氧条件下，底质中Ｆｅ、Ｍｎ重新释放，形成明显的Ｆｅ、Ｍｎ分布垂直梯度，造成水库下层Ｆｅ、Ｍｎ大大超过国家生活饮用水质量标准。

Considering the effect of water flow on the transportation of Fe and Mn and describing its processes of redox,sorption,desorption,deposition and re suspension in the reservoir,a joint 3 dimensional mathematical model for the hydrodynamics and the transportation of Fe and Mn was developed.The model simulated both horizontal and vertical gradients of Fe and Mn in Arha Reservoir.It was found that Fe and especially Mn stratify in accordance with the stratification of DO during summer.The redox cycles across the water sediment interface play a principal role in the rise of Fe and Mn concentrarions in the overlying water.It was also found that Fe and Mn loads from the tributaries have a carryover effect on the water quality through a secondary contamination in the reservoir.