Identification of LNAPL phase of oil contaminants in the aquifer of Bandar Abbas Oil Refinery

Oil fields, refineries, pipelines and gas stations are potential sources of pollution that can be release oil contaminants into the environment. There is some evidence of groundwater pollution in the aquifer of Bandar Abbas oil refinery.

To determine the origin of pollutants, the aquifer properties, such as depth and direction of groundwater flow, aquifer body material and hydrodynamic coefficients 143 groundwater monitoring wells were monitored and the groundwater samples were analyzed. For detailed study 6 new wells were dug in the one of the pollution mound. Groundwater depth, thickness and origin of the oil release were determined.

The refinery aquifer is an unconfined aquifer with a body of marl and limestone with a thickness 3 to 17 meters. Depth to water table, 3 to 3.60 m, hydraulic conductivity 2.45 meters per day and the general direction of flow is determined from North West to the South East. The average velocity of groundwater in the aquifer estimated as 2× 2-10 m/d, and contamination by LNAPL phase was detected at least at 11 wells.

The maximum and minimum thickness of LNAPL is 115 and 0.05 cm, respectively, located at the west of the refinery. A variety of oil pollutants from gasoline and crude oil to phases with high viscosity, such as fuel oil leads to aquifer contamination. Leakage from tanks contains gasoline, diesel, kerosene and transmission channel from washing of Unit 71 to the Recycling Unit are determined as the main sources of aquifer contamination.