Studying the Trend of Changes in the Contamination Concentration Caused by Leakage Leachate of Hypothetical Landfill in Rafsanjan Aquifer

Background & objeftive: In the Rafsanjan sites have been considered in the studied region for landfill construction, where the leachate diffusion caused by landfill for groundwater resources, which is the only source of water supply in this region, is a serious threat. The aim of this research is to study the trend of changes in the contamination concentration due to diffusion of a hypothetical landfill based on the geological and hydrogeological conditions of Rafsanjan plain in order to represent the effect of leachate diffusion and contamination spread across groundwater resources.
Methods and Materials:Transmission of contamination has been studied on the basis of changes in concentration at two initial and final points of landfill by MT3DMS model daily and for 22 years period. The concentration of leachates has been considered 2 and 4 g / l, and its diffusion rate has been assumed 1.5 and 3 cm per day.
The slope of the concentration increase in the propagation process and delayed diffusion at the beginning of the landfill with 2 and 4 g/l concentration and 1.5 cm rate during 15 and 17 years have an increasing trend, respectively and later it would have a decreasing trend. At the end of landfill, 90% increase in contamination will occur for 2 g/l concentration in the first five years and 4 g/l concentration in the first 9 years and it will have a fixed trend over the next few years.
In the various transmission processes after the penetration of the infection into the aquifer, the concentration of contamination is initially low and increasing over time and if the concentration of the source of the penetrating source of constant intensity is constant, the maximum concentration of aquifer pollution is fixed at a certain value. the type of transmission process has a huge impact on this constant value. So that in the propagation-diffusion process, the average in the first 5 years of this value is fixed and in a delayed state, it reaches a constant value after close to 22 years.