Study On Transport-Transformation Of The Combined Pollutants In Aquatic Environment

The influence of the pollutants adsorption and sediment motion on the pollutants transfer characteristics was studied in this paper. Unsteady-unsaturated sediment transport model and pollutants transport and transformation model were developed. The models were tested by numerical simulation of the water flow and sediment transport in the lower channel of Guanyinyan Hydro-power Station and of the concentration distribution of TP (Total Phosphorus) in the Yangtze River from Qingxichang to Wanxian section. The sediment motion and water quality model were established based on the characteristics of aromatic hydrocarbons in the Yellow River from Lijin to Qing7 section, and the transport and transformation of the aromatic hydrocarbons, especially the adsorption competition of the combined pollutants, were discussed.The unsteady-unsaturated sediment transport model was developed based on the water and sediment motion equations. The validity of the model was verified by the measurement data of water level and sediment deposition and erosion in the lower channel of Guanyinyan Hydro-power Station. The soluble and absorbable pollutants transport and transformation models were built and the absorption dynamic equation was used to determine the parameters of models. The observation data of soluble and absorbable TP in the Yangtze River from Qingxichang to Wanxian section were used to test the models. The test results were satisfied.The Yellow River has been polluted by combined organic pollutants, especially the estuarine zone from Lijin to Qing7 section. Therefore the water quality model of aromatic hydrocarbons (including phenol, aniline and chlorobenzene)is established. Based on the calculation of the water flow and sediment motion, the transport and transformation of combined these three pollutants have been studied, and the adsorption competition of the combined pollutants has been analyzed. The calculated results showed that the erosion happens in the upper river and the deposition appears in the lower river, the concentration of soluble pollutants decreases along the river, especially when the quantity of the runoff and sediment is very large. The absorbable pollutants concentration distribution is other way round. Compared to the single pollutant, combined pollutants happen mutually the adsorption competition. It is concluded that the adsorption competition capability of aniline is strongest and the adsorption competition capability of phenol is weakest.