Brief Description of Project:
“Manufactured Gas Production” is a term describing the process of using coal or petroleum to provide the gas
municipalities used for lighting, heating and cooking in the early 20th century. As late as the 1940’s, half
of the gas produced in the US came from manufactured gas plants (MGP). The by-products of gas manufacturing
include residues containing polyaromatic hydrocarbons (PAHs) which are hazardous volatile and semi-volatile
large-ringed organic chemicals (e.g., naphthalene is a PAH used in moth balls). Waste handling policies of
the MGP era have left a legacy of contaminated sites for which remediation steps are required. One such remediation
option is in-situ stabilization (ISS) - where contaminated soils are mixed with cement and additives with the
goal of immobilizing the PAHs within the cement matrix. ISS is a cost-efficient method used by many site owners
for remediation at MGP sites; however, the effectiveness of this treatment for retaining PAH contaminants has
not been clearly demonstrated.
The objective of this research is to develop and demonstrate an approach to estimate leaching of PAHs from ISS
treated soils from former MGP sites. The assessment approach is based on integrating the characteristic leaching
behavior of the waste material (e.g., as derived from laboratory leach testing) with release modeling using release
scenario-specific parameters. Resulting estimates of leaching, which would consider changes in release as a function
of time, site-specific conditions and material, physical form and aging, are to be used as that basis for determining risk
to groundwater, developing remedial objectives and assessing treatment process effectiveness
For this summer project, the release of PAHs from previously treated MGP samples will be characterized under
controlled laboratory conditions to develop a characteristic leaching profile of the material. The leaching profile
is critical to the overall project as it becomes the basis for modeling of contaminant release under conditions
expected in the field at the former MGP sites. Students will learn the basics of how contaminants are transported
from solid wastes into the environment, protocols for assessing the impact of leaching on the environment, and
associated chemical analysis techniques for determination of PAH concentrations in liquid samples.
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