Numerical Simulation of Fertilizers Movement in Sand and Controlling Transport Process via Vertical Barriers

Abstract

—Intensive application of inorganic compounds for agriculture activities leads to increased percolation into the subsurface and can end up in the groundwater. Nitrate is considered a moderate solute in soils and could move quickly through the soil especially on sandy or permeable soils profile leading to groundwater pollution. This paper presents an application of numerical models in order to investigate the migration process of nitrates through sand. Two software products, SEEP/W and CTRAN/W, are used to analyze the contaminant transport. These models can be used to optimize agricultural practice aiming to minimize the impact on the environment. Nitrate sorption in the sand is influenced by environmental conditions which contributing to the migration process of nitrate in soil. The behavior of nitrate transport through sand is tested when vertical wall of sheet pile is used as a barrier. The involved parameters are the penetration depth of protection wall, location of wall from the pollution source, and the head deference of the water level. The results show that the physical properties of soil have significant effect on the movement of the contaminant. Also, the results indicate that the change in head difference has insignificant effect on the contaminant migration process. Finally, the best location and depth of the vertical barrier are determined to minimize the proportion of the reached contaminant to attain the maximum possible protection of the drain's water.