Study On The Migration And Transformation Of The Coal-fired Pollutant In The Vadose Zone

In the future,thermal power for a long time will be the main power of our country,at the same time,thermal power will bring a lot of environmental problems,including in groundwater pollution which is to be solved necessarily.Plants produce waste and liquid leachate probablely through the vadose zone into groundwater.The vadose zone with the characteristics of self-purification ability play a crucial role in reducing pollution,so it is essencial for reseachers to study the contaminants,migration and transformation contaminants in the vadose zone.The paper that based on China power engineering consulting group northeast electric power design institute,carry out coal-fired power plant pollutants migration and its effect on groundwater environmental research.According to the literature at home and abroad,we selected ammonia nitrogen as the research object.To study the characteristics of ammonia nitrogen pollutants during the process of migration and transformation in the vadose zone migration,we carry out the laboratory experiment,aiming to research the main degradation – adsorption and simulate the transformation process of ammonia nitrogen in the vadose zone finally,using Hydrus 1D software build a vadose vertical one,along with experiments datas to calibration and validation the model parameters.We also use the numericial model to predict the diffirent situations.Following are thesestudies shows:1.Adsorption kinetics experiments showed that the adsorption process of sandand clay was instantaneous,and reached equilibrium completely after 360 minutes.The best adsorption mode for silty clay and silty loam was Langmuir adsorption mode through ammonia nitrogen adsorption thermodynamics experiment.The effects of ammonia nitrogen,fluorine pH and temperature on isothermal adsorption behavior were analyzed.It was found that when the two soil samples were at lowconcentrations,the temperature change had little effect on the adsorption performance of ammonia nitrogen and fluorine.The lower the concentration,the higher the adsorption capacity.The adsorption capacity of silty clay and silty loam soils increased with the increase of pH from pH 3-10.2.The diffusion coefficient and dispersion of silty loam and silty clay were calculated by the soil column experiment chloride tracer test and the contaminant leaching test.The breakthrough curve of two pollutants is compared with the breakthrough curve of chloride ion,and the effect of pollutants in different aeration zone media is analyzed based on the comparison results.3.Using Hydrus-1D software simulation,the simulated penetration curves and measured values of chlorine ions in the two soil samples were obtained and their consistency and fitting degree were determined.The best fitting value of the longitudinal dispersion coefficient DL was obtained.By parameter inversion,the best fit value of the solute reaction parameters Kd and Nu for the breakthrough curve of the pollutants is obtained,and based on the best you can analyze the physicochemical effects of contaminants in the vadose zone.Predicting the distribution law of pollutants in the thickness of the aerated zone under atmospheric boundary conditions,it is found that pollutants under atmospheric rainfall evaporating conditions are not easy to penetrate the aerated zone;the breakthrough curve under a single pollution condition is predicted,and it is found that the primary pollution is more Conducive to the degradation of pollutants.