Abstract
An one-dimensional finite element mass transport model with nitrogen species transformation was developed to predict the transport of nitrate-nitrogen (NO3-N), nitrite-nitrogen (NO2-N), and ammoniumnitrogen (NH4-N) in porous media. Field experiments using sulfate ammonium wereperformed and temporal and spatial distributions of NO3-N concentration and volumetric water content were measured. The numbers of nitrifers and denitrifers, and pH values were also measured. The rate of aquifer recharge and rate coefficients of the transformation were calibrated to fit the measured distributions of water content and NO3-N concentration at 28th day of experiments. The validity of this model was examined and confirmed by comparing the results of numerical analysis under the calibrated values with measured data at 42nd day of experiments. It was found that there is a good correlation between the number of microbe and rate coefficients, which greatly affect the prediction results. The variation of the NO3-N concentration is able to be predicted through this model in the experimental site when appropriate rate coefficients are used based on environmental conditions, which have the effect on microbial activity.
