模拟生活污水在排水管网中的COD浓度变化

Simulation of Sewage COD Concentration Variation for Municipal Drainage Pipe Network

以一维移流扩散方程为基础,针对排水管网中常用的混凝土圆管排水管道,建立排水管道化学需氧量(COD)浓度模型,运用有限差分法对模型进行求解,并利用VB和Excel进行实现。经现场试验验证,模型可较好地模拟污水在单管排水管道输送过程中的COD浓度变化,模拟值与实测值的最大相对误差为2.5%。以珠三角某镇排水管网为例,进一步结合节点混合模型,模拟城镇生活污水在排水管网传送过程中的COD浓度变化,模拟结果表明,模型的各参数计算及取值较为合理,能准确地反映出实际污水处理厂进水COD浓度,模拟值与实测值的相对误差为6.6%。运用此模型有助于预测判断排水管网各节点的污水COD浓度,尤其是污水处理厂的进水COD浓度,有利于对城镇排水管网进行管理。

In allusion to round crosssection concrete sewage pipe, the mathematical model of sewage COD was built based on the onedimensional diffusing equation. And solution of the model was performed with the finite difference method and program of Visual Basic and Excel. The results show that the model predicts the variations of sewage COD concentrations in the process of sewage transmitting along the sewer well, and the maximum relative error between the simulated data and the measured data is only 2.5%. Taking the sewage pipe network of a town in Pearl River delta region for example, and further combining with mixed-node model, the variations of sewage COD concentration in municipal sewage system was also stimulated. The results show that all the parameters of the model are reasonably calculated and set and the model predicts the influent COD concentration of the sewage treatment plant quite well. The relative error between the simulated value and the measured value is 6.6%. Therefore, the model is able to make predictions and judgments on sewage COD concentration of the nodes, and is of benefit to the management of municipal sewage pipe network.