Experiment And Numerical Simulation Of Heavy Metal Transport

At present, a number of water bodies are polluted with heavy metals to different extend, and in some of them the situations are quite serious. Due to the process of enrichment, heavy metals can affect the entire food chain. As heavy metals flowing into the water, it will be quickly absorbed to sediment, so sediment and water are the common carriers of heavy metals. Heavy metals exchange between sediment and water continuously. A part of the heavy metal settles down to the bed with the sediment particles. Under certain conditions the heavy metals in the bed sediment can be released to the water body, result in the second pollution. Compared with organic pollutants, heavy metals are more stable, they can be used as the indicators for studying the transport of sediment.The experiments were carried out to understand the transport of heavy metal in the bed sediment. Firstly, the adsorption kinetics and adsorption isotherms were tested and the optimal adsorption conditions, the maximum adsorption capacity and adsorption coefficient were determined. Secondly, based on the adsorption kinetics and adsorption isotherms, the experiments were carried out and the vertical distributions of heavy metal were measured under different disturbance conditions.The numerical model developed by our group was applied to simulate the transport of sediment and heavy metal in a flume, and the performance of the model was evaluated by comparing the numerical results against the measured data. The results show that the predicted bed forms are in good agreement with the measured data, while the predicted distributions of heavy metal are not very satisfied most possibly due to the over simplified bed boundary condition.