Study On Transport And Numerical Simulation Of MTBE In Underground Surroundings

Study on organic transport in underground surroundings is an important step for investigating the pollution caused by organic compounds. The target of the study is to monitor and forecast the transport speed and polluted area by studying the transport and transform of organic pollutants in underground environment, which supplies references to the further environmental treatment work. As a new kind of gasoline additive, methyl tert-butyl ether (MTBE) poses great harm to the soil surroundings. Because of greater solubility and high difficulty of biodegradation, MTBE has the special character differs from the conventional organic pollutants. But the research on its transport and transform in underground environment is comparatively less. Basing on this background, the transport and transform of MTBE in soil unsaturated zone and saturated zone is specially investigated.Mass transfer equation is firstly analyzed in the thesis. The application scope of the model and required parameters is illustrated. Obtain soil physical parameters and model parameters by experiments.Making the quartzite sand and the sandy soil in the development area as the medium, the experiment mainly investigate the soil's physical properties, the model parameters and the transportation condition of MTBE in one-dimensional soil column and two-dimensional sandbox.The penetrability parameter of soil is attained by soil penetrate apparatus. Adsorption partition coefficients of MTBE in 20-40 mesh coarse sand, 50-80 mesh fine sand and mixed sand is obtained by adsorption equilibrium experiment. The kinetic characteristics of adsorption of MTBE in deferent mediums are acquired by kinetic adsorption experiment and the adsorption process is approved to be reversible. By the soil diffusion experiment, the effective coefficients of MTBE gas phase in coarse sand, fine sand and sandy soil are obtained. The effective coefficients differ with a discrepancy of an order of magnitude with the soil grain size decrease from coarse sand and sandy sand. And the dependability of effective coefficients in different medium is illuminated.Adopting one-dimensional soil column experiment simulates the vertical transport of MTBE in unsaturated zone of soil and draws the conclusion that the transport speed decreases with the water content increases from the top to the bottom.