Investigation into the remediation of petroleum contaminated soils by soil washing

Abstract

Contamination of soil by hazardous compounds such as petroleum hydrocarbonsposes an ever increasing threat to our environment. There are several methods with whichcontaminated soil can be remediated.The purpose of this study was to investigate the effectiveness of remediatingpetroleum contaminated soils by a method known as soil washing. For this study, dieselfuel was used as the contaminant. Two different soil types were used in this study; astandardized sand and a silty sand (soil type SM). The contaminated sand was washed withboth water and a non-ionic, biodegradable surfactant known as Emulgin ET -2. Thecontaminated soil was also washed with water, but a different non-ionic, biodegradablesurfactant, Simple Green, was used as a washing agent.A variety of different analytical methods were used in order to determine the amountoffuel remaining on the washed sand/soil and to also determine how much fuel wastransferred to the aqueous wash. These methods included Soxhlet extraction andGravimetric analysis as well as analysis by Gas Chromatography.The results from this study seemed to indicate that water proved to be an effectivewashing agent, as it removed the bulk of the diesel fuel from both the sand (82 percent byweight) and the soil (91 percent by weight). The Emulgin ET -2 was able to remove slightlymore diesel fuel from the sand (93 per cent removal at 1:2500 concentration of thesurfactant), whereas the Simple green appeared to inhibit the removal of the diesel fuel fromthe soil (76 per cent removal at 1: 1000 concentration of the surfactant).