多泥沙河流水质模型研究

Simulated research on water quality for such heavy sediment-containing rivers like Yellow River

针对黄河泥沙含量大、泥沙对河流 CODMn浓度影响大的突出特点 ,运用模拟实验方法 ,探讨了泥沙对 CODMn浓度的影响 ,揭示了浑水、清水中 CODMn浓度与含沙量间的关系。研究表明 ,黄河浑水中CODMn浓度随含沙量增大呈显著上升趋势 ,而去除泥沙后清水CODMn浓度测定值随其原含沙量增大呈微上升趋势。依据质量平衡原理 ,建立了充分考虑泥沙影响的 CODMn衰减经验模型。清水中CODMn浓度的变化采用完全混合反应器概念来模拟 ,浑水中 CODMn浓度通过清水中 CODMn浓度与泥沙中 CODMn浓度之和来量化。模型基本方程的求解采用稳态解析解。模型中的参数通过利用实际监测数据及室内实验结果与优化结合的方法确定。同时 ,利用实际监测数据对参数和模型进行检验。结果表明 ,模型结构合理 ,参数取值可靠 ,模型精度较好。模型既能揭示汇流区间人为污染对河段水质的影响 ,又可以反映作为面污染源的黄河泥沙对污染的影响 。

The present paper introduces the author's simulated research of the influence of the sediment on the water quality of the river and the pollution involved. The simulation experiment here introduced has been used to study the changing situation of the water quality in the Yellow River, focusing on the study of the characteristic features and the influence of the sediment on COD_(Mn) concentration. The relation between COD_(Mn) concentration in the body of the muddy water and sediment concentration is shown delineated in the experiment, which means that the COD_(Mn) concentration in the water is getting higher and higher with the sediment level increased. However, the COD_(Mn) concentration in clear water body of the River is going up slightly with the original sediment concentration increased. According to the Mass Conservation Law, we developed the COD_(Mn) attenuation model (with the influence of sediment sufficiently considered) in this paper. In our model, the change of COD_(Mn) concentration in clear water is simulated by solving the water quality equation with the concept of full mixed reactor. And the COD_(Mn) concentration in the muddy water is quantified by the sum of the COD_(Mn) concentration in clear water on the condition that the COD_(Mn) concentration is in suspended sediment. Since it is possible to solve the fundamental equation by means of stability analysis, the parameters of the model (which can be inferred from the models verified based on the monitoring data at the Point Mengjin to the Point Huayuankou in the River's middle reach in Henan) can be established by combining the monitoring data, experimental results and optimization technology. Thus, it can be seen from the above results that the simulated model structure is rational with all the parameters being reliable and the model precision satisfactory. The model can not only reveal the effect of artificial pollution in a confluence area on the water quality at the corresponding section but also reflect the influence of the sediment on the COD_(Mn) pollution. Hence the model is applicable for predicting water quality as well as for programming and management.