Experiment and Numerical Simulation on Transportation of Ammonia Nitrogen in Saturated Soil Column With Steady Flow

Ammonium nitrogen in groundwater is one of the nutrient elements in the key monitoring indexes during the infiltration of water. Our objective of this study is to understand the adsorption and transportation characteristic of NH3-N in the sandy loam. The calculated distribution coefficient (Kd) and retardation factor (R) of NH3-N in the sandy loam was determined using the batch and Freundlich adsorption isotherm. We also got the break through curve (BTC) of NH4+ in saturated sandy loam by mixed displacement experiment. To verify the accuracy of the adsorption parameters, using the effluent data from a pulse change input miscible displacement experiments, by solving inverse problems of the equilibrium and chemical nonequilibrium convection-dispersion equation with the computer code (CXTFIT 2.0), we estimated the optimized values of the retardation factor. These results indicate that the adsorption parameters calculated by our experimental data are in agreement with those estimated by the empirical formula.