Sparing the ROD and Unspoiling the Groundwater: A Superfund Landfill Groundwater Remediation Success in Vermont

Working for a multinational manufacturing company, URS completed the implementation of groundwater remedial measures at a Superfund landfill in Vermont. URS demonstrated that a revision of the ROD remedy from pump and treatment to a combination of passive and semi-active treatment controls would effectively treat groundwater and reduce clean-up costs by $20 million. URS evaluated alternative technologies and to demonstrate corresponding performance effects. The evaluation successfully resulted in EPA's issuance of an Explanation of Significant Differences changed to the ROD. The selected remedy included construction of a source-area permeable reactive barrier (PRB) coupled with a bio-enhanced attenuation system to treating downgradient groundwater. The 235-foot-long, 62-foot-deep PRB was installed by slurry wall construction methods and employed variable iron content media placed in sections of the wall to reduce the quantity of reactive media required. The bio-enhanced attenuation system enhanced in-situ microbial degradation treats groundwater depths of between 120 and 160 feet by injecting a solution containing sodium lactate and nutrients. Monitoring of the two treatment systems indicates that significant destruction of contaminant mass is occurring.