Using hydraulic testing to evaluate LNAPL recovery in fine grained systems

Petroleum fuels are the most common and widespread contaminants requiring management in urban and industrial environments. These contaminants are commonly referred to as light non-aqueous phase liquids (LNAPLs)(Johnston 2010). LNAPLs are hydrophobic liquid organic chemicals with lower density than water and immiscible with water. They include a wide range of substances, but the most common types are oils and fuels, such as diesel, jet fuel and petrol (gasoline) (Kirkman, Adamski & Hawthorne 2013). In the present study the recovery of LNAPLs from a gasoline fine grained contaminated site in Western Australia is measured. The aim of this work is to evaluate the LNAPL recovery of the site via short term baildown tests versus recovery trials. Baildown tests have been proposed as a metric for the estimation of NAPL recovery but the majority have been conducted in homogeneous settings with little existed data from more complex subsurfaces. The calculation of the LNAPL transmissivity values was the outcome of the recovery tests. Wells with similar transmissivity values can be used and compared easier later during the remediation processes. (author)