Groundwater Contamination
Superfund Site
Woburn, Massachusetts

Municipal drinking water wells had become contaminated with chlorinated compounds.  First detected in 1979, the events surrounding this site later became the subject of the movie “A Civil Action.”

The Johnson Company’s client was one of several potentially responsible parties. A solution was needed for our client’s remedial responsibilities, but without attempting to clean up the entire aquifer which had been impacted by many other contamination sources.

The Johnson Company was a primary member of a subsurface investigation and research team of experts to determine the hydrogeology and contaminant transport parameters of DNAPL at this fractured bedrock site. Our findings were used to support the planning, negotiations, and selection of an appropriate remedial action for the site as well as the successful defense of a $250 million litigation.  The work culminated in a negotiated remedy with EPA which involved hydraulic capture of contaminants using pump and treat methods.

The Johnson Company’s hydrogeologists and engineers worked together to locate and design a pumping well that would sufficiently capture the contaminated groundwater within a specified zone while minimizing the amount of pumped water requiring treatment prior to discharge to surface water.  The Johnson Company’s engineering staff then designed, installed, and operated the groundwater pump-and-treat system consisting of ultraviolet light and hydrogen peroxide treatment for oxidation of chlorinated compounds followed by carbon as backup treatment. The system has operated nearly continuously since start-up with no detections to date of chlorinated compounds of concern in the discharge water.

The Johnson Company continues its review of the remediation system and the on-going contaminant mass removal and destruction, hydrogeologic interpretation related to the groundwater pumping system, and annual field audits of the long-term monitoring program.

A result of our work was to convince regulators that complete clean-up of DNAPL in bedrock at this site is infeasible and the most appropriate strategy is to manage migration. Our client’s responsibilities are being met through the continuing hydraulic capture of their portion of the contamination with a cost-effective treatment system that includes remote monitoring.

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