| Abstract: | In June 2001, the Massachusetts Department of Environmental Protection (DEP) installed a permeable reactive barrier (PRB) within a roadway in Needham, Massachusetts, to treat a plume of chlorinated solvents migrating toward two public water‐supply wells located in the adjacent town of Wellesley, Massachusetts. The solvents originated from an electronics manufacturer located approximately 2,300 feet upgradient of the roadway and 5,200 feet upgradient of the public supply wells. Chlorinated solvents, primarily trichloroethene (TCE), had migrated past the roadway to within 300 feet of the public supply wells. Two contaminant transport models prepared by the DEP's design contractor and the EPA indicated that the plume would reach the well field if no response actions were taken. To mitigate the future impact to the municipal well field, the DEP decided to install a PRB composed of zero‐valent granular iron across the path of the plume along Central Avenue in Needham. Though several dozen PRBs have been installed at sites worldwide and the technology is no longer considered innovative, the application of the technology in a roadway that receives 17,000 vehicles per day within a residential neighborhood is unique and presented difficulties not typically associated with PRB installations. The Needham PRB was also one of the first zero‐valent iron PRBs installed using the slurry trench method to treat chlorinated compounds. © 2002 Wiley Periodicals, Inc. |
