Determination of solute transport parameters for remediation of hydrocarbons from ground water in Antarctica

Abstract

There are many contaminated sites in Antarctica as a result of accidents or poor waste management. A significant proportion of the pollution is from oil and its derivatives and heavy metals. Although it's a common perception that hydrocarbon spills in frozen grounds are immobile, fuel components have been shown to be highly mobile in soils and sediments with low organic contents specifically during the summer snow melting season. The low temperature and low nutrient soils in cold regions make the natural attenuation rates much slower as compared to temperate climates. Therefore, more active remediation options are often sought for such sensitive areas. Permeable reactive barriers (PRB) are one such option. They are an in situ passive treatment technology that removes dissolved contaminants from polluted water through subsurface emplacement of reactive materials and are widely applied. But to install a successful PRB in cold regions, it is important to understand the flow path and solute transport mechanism in frozen including axial dispersion and the reaction of solute. This paper will discuss about the modeling tool to determine the contaminant transport behavior with minimal amount of data requirements, as acquiring significant amount of field data in such environments is practically not often possible. This study also investigates the impact of temperature and axial flow on the sorption column performance to adsorb hydrocarbons by studying breakthrough point and breakthrough curve at various flow rates and development of a model to predict the solute transport parameters. Toluene has been used as a representative soluble aromatic hydrocarbon in this study. Inverse modeling has been utilized using the computer program CXTFIT to determine the variable parameters, axial dispersion coefficient and porosity. A set of partial differential equations was solved to describe the solute flow through, with appropriate initial and boundary conditions in order to develop a model to predict the future PRB and its performance in the field.