Title: "Movement of light hydrocarbons through limestone: analysis of contaminant composition"
         

DOI: 10.15224/978-1-63248-114-6-21
Page(s): 46 - 50
Authors: ENDER OKANDAN, SHIRIN SEPEHRI

Abstract

Spillage of petroleum products in soil, rivers and lakes is a problem since the advent of the petroleum era. Contamination of groundwater is one of the most important hazard of spill because it is a threat to animals, plants as well as human life. Fingerprinting of oil spills plays an important role in order to select the best treatment and cleanup method. Factors such as penetration depth of the oil into the soil, type of oil and polluted soil and the age and degree of contamination determine the efficiency of soil remediation. In this study, an experimental model was used to investigate the movement of a hydrocarbon liquid such as diesel oil and gasoline in soil where crushed limestone was the soil medium. A plexiglass cylinder with three ports at three different depths (in order to collect samples) was constructed. It was filled with crushed limestone. The design enabled to collect samples, analyze them and understand the mechanism of contaminant downward movement. Samples were collected at different time intervals from ports and analyzed by gas chromatography to obtain chemical compositions of the contaminants. Penetration depth of different contaminants at different time intervals were investigated in this study. By comparing behavior of diesel oil and gasoline, it was observed that the downward movement rate of gasoline is higher due to possessing lower viscosity than diesel. So, it reached to the dipper depth at the same time interval. As a result, gasoline spillage requires more rapid action to prevent groundwater contamination. On the other hand, Residual non-Aqueous Phase Liquid (NAPL) saturation in this sand pack is higher in the case of viscose contaminant spillage which is diesel oil in this study. The reason is downward movement of the diesel oil is slow and the contaminant has more time to occupy available pore spaces in its downward path. So the concentration of the contaminant would be high. Which leads to critical results to select the best remediation technique.