Experimental and numerical modeling of salt and water movement on soil lysimeter influenced by wastewater

Irrigation by wastewater poses risks for deterioration of the hydraulic soil properties and pollution of groundwater. To reduce the risk of surface and ground water contamination from salinity, and in doing so, improve the quality of receiving waters, better management options for land application of wastewater must be explored. In order to study these concerns. The simulation accuracy and performance of the Hydrus-۱D model to predict salt transport has been evaluated and compared to lysimeter data. More specifically, the effects of irrigation using four types of water (wastewater, effluent, mixture of freshwater and effluent, and freshwater) on three types of soil (sandy loam, loam, and clay loam) has been investigated both experimentally and numerically.The numerical simulations, indicate that the effect of irrigation water and soil type on the EC drainage lysimeter was significant at the ۵% level. The highest EC drainage was in clay treatments, followed by sandy treatments, and finally loamy treatments. The results of the experiments showed that the EC of leachates, being greater than the EC of the irrigated waters, was mostly a function of the soil background salts. The Hydrus-۱D can also serve as a useful tool in evaluating the impact of agricultural activities and formulating efficient water management strategies. On the basis of the results, soil with a loamy texture is considered to be the most suitable for irrigation with wastewater and effluent. The simulations results of this research indicate that with a proper management program in regard to the types of soil to be used, crops to be cultivated, water quality and timing maneuver, the negative impacts of low quality water on soil/plant/groundwater systems can be minimized.