Affiliation: Gillings School of Global Public Health, Department of Environmental Sciences and Engineering
Manufactured gas plant (MGP) operations across the United States during the late 19th and early 20th centuries resulted in the release of polycyclic aromatic hydrocarbons (PAH's) into soil and groundwater systems, leading to degradation of groundwater quality and creating public health risks. Former MGP sites require appropriate cleanup methods; this study uses PAH-contaminated field soil to examine the potential for cosolvent flushing as an efficient remediation technology. Batch experiments examined the desorption and solubilization of PAH's with cosolvent solutions; a log-linear relationship between cosolvent volume fraction (fc) and equilibrium partitioning coefficient Kp was observed. A linear relationship between fc and the percentage of PAH's removed from the field soil was also noted. Cosolvent effects on individual PAH's increased with solute hydrophobicity, represented by log Kow. Column experiments studying the transport of PAH's with flow observed more efficient contaminant removal with an increase in solution fc. A large-scale column experiment designed as a simple representation of PAH transport in a field setting found an estimated 93% removal of contaminants after 13.6 pore volumes (PV) of flushing with a 95% methanol solution.