Analyzing the Effect of Source Geometry on NORM Concentrationin Groundwater

Assigning protective measures in designing safe landfills to ensure the confined disposal of Naturally Occurring Radioactive Materials (NORM) and future protection of public and environmental health, is among the most important NORM management challenges. In this context, the fate and transport of NORM in groundwater should be understood. Mathematical models are effective and reliable tools to study and predict the behavior of the contaminants in different porous media. In thisresearch, three different analytical solutions of mass transport equation have been applied for a NORM landfill and the results are presented to evaluate their performances. Analytical solutions have been derived based on the leakage geometry which occurs as point, line and area geometries. Each model were run with MATLAB-Simulink as a dynamic system following the compartment modelling technique. One of the local evaporation ponds at Ramin oilfield has been selected as the main case study. In order to have a better understanding of the models, effect of solid-liquid distribution coefficient have been studied using sensitivity analysis. Results for NORM concentration at the receptor well indicates thatpoint geometry is the most conservative approach. The results introduce the point model as the most conservative one. On the other hand, area model seems to be the most realistic which exerts the effect of distribution coefficient and arrival delay better than the rest. This paper deducesthat the area model is the most efficient and flexible solution but recommends to select the desired geometry according to the objectives, safety standards and available budget.Comparing the effect of source geometry for release of NORM has been investigated for the first time in this paper. This research applies analytical solutions which are widely common in different environmental modellings. The main goal of this study is to compare the results from each model in order to determine their degree of conservatism and help researchers and stakeholders to select their favorable model. Distribution coefficient of NORM and their effect on different solutions has been also investigated, which is not studied in other similar papers.

کلیدواژه ها:

NORM ، Source geometry ، Groundwater ، Analytical solution ، Landfill ، Distribution coefficient