عنوان مقاله [English]
Environmental pollution, especially the increasing trend of water resources pollution caused by oil spills, is one of the main concerns of advanced human societies. Considering the dangerous nature of oil contamination for the environment as well as the development of various diseases such as pulmonary and skin diseases and cancer, it is very important to purify the environment.
Material and methods:
In the study area, Shahr-e-Ray industrial zone, south of Tehran, petroleum activities have led to aquifer pollution, so that in some parts the thickness of light non-aqueous phase liquid (LNAPL) on the surface of the groundwater reaches more than 20 meters. Since the LNAPL acts as a source of exceeding pollution in the groundwater, in both saturated and unsaturated areas, it is necessary to purify the aquifer, which contains LNAPL fluid. In this regard, awareness of hydrodynamic parameters of the aquifer such as transmissivity and hydraulic conductivity is of great importance and even determinative of the type of recovery methods.
Results and discussion:
Because of the hydrogeological conditions of Rey industrial zone, LNAPL thickness and also time limitations, the Baildown test was used to determine hydrodynamic parameters of the aquifer, including transmissivity and hydraulic conductivity. This method involves removing the entire LNAPL from the casing and filter pack by moving part of the volume to create head differences. Afterwards, the fluid level is measured during removal.
Regarding the results of the Baildown test, the range of LNAPL transmissivities in the aquifer varied between 0.085 to 11.506 m2/day and the range of hydraulic conductivities varied 0.01 to 1.62 m/day. According to the Baildown test result, the highest transmissivity of LNAPL in 10 wells was observed in the eastern and northeastern regions of the study area.