Numerical modeling of petroleum contaminants transported in groundwater probable leakage from Khoy oil storage tanks, West Azarbaijan, Iran

Abstract

In this research concentration and extent of soluble contaminants plumes caused by probable leakage of petroleum materials from Khoy Oil Products Storages and also transporting mechanism of pollutants by groundwater was investigated. Groundwater flow model for a steady and transient state was simulated using MODFLOW- 2000 code. Then, flow model calibrated and the aquifer hydraulic parameters were estimated. Flow model output and calibrated parameters were used for simulation of BTEX and MTBE transported by MT3DMS code. Three scenarios were considered to predict transporting of pollutants under various conditions. The model results suggest that the plume MTBE in the condition of continuous source will be distributed up to 774 meters whereas it will distribute about 108m far from the source if the leakage stops after three years. According to the model prediction, the extension of BTEX will be less than MTBE in the case of continuous leakage. Under condition of the second scenario (non-continuous release of the pollutants) the plume extension of benzene reach will be 126 meter after 10 years and it can reach to the nearest abstraction well in 8.5 years. MTBE plume size in this period reaches to 6 times of BTEX and will reach the well in 1.5 year. Average velocity of contaminant distribution is about 5 to 6 cm per day. It is predicted that the MTBE plume reaches earlier to the first pumping wells related to BTEX. So maintenance of the Oil tanks and monitoring of the downstream groundwater is a necessity. Average velocity of contaminant distribution is about 5 to 6 cm per day. It is predicted that the MTBE plume reaches earlier to the first pumping wells related to BTEX. So maintenance of the Oil tanks and monitoring of the downstream groundwater is a necessity.