Simulation of nitrate transport and fate in groundwater in presence of kaolin

Abstract

It has been found that aquifers containing clay particles possess a natural capacity of pollution attenuation and thereby are able to mitigate the effects of contamination.The main objective of this study was to simulate nitrate (NO3) movement and fate in porous media in presence of clay kaolin using a numerical and physical model in order to estimate the pollution attenuation capacity of kaolin. A noncommercial solute transport model known as Ground Water Key (GWK) was used to simulate NO3 concentration in an idealized physical model for this purpose. Nitrate polluted water at level 112.5 mg NO3 L–1 was introduced to the porous media of the physical model for experimental data collection and validation of numerical simulation by GWK.The results revealed that the GWK model can estimate NO3 concentration with a high level of accuracy in porous media in presence of kaolin. Nitrate concentrations in porous media and the dispersion coefficient were found to be sensitive to initial NO3 concentration.The results also revealed that kaolin can retain NO3 and thus is able to reduce NO3 pollution by approximately one-third. It is expected that the study results can be helpful in groundwater monitoring and protection.