Going Into the Project with Your Eyes Wide Open

One way to avoid major unanticipated construction costs is to conduct a comprehensive environmental due diligence study early in the design phase of a redevelopment project, an eastern Massachusetts high school under construction benefited tremendously by following Wheatstone’s advice.  The in-situ remedial approach implemented by Wheatstone saved the project millions of dollars as compared with traditional excavation, transportation and disposal of petroleum contaminated soil. This allowed construction of the building to occur concurrently with the remediation, eliminating months of construction delays. The project is being considered for awards for seamlessly combining the construction and in-situ remediation activities, while saving the city millions of dollars.

 

During preconstruction assessment activities, Wheatstone discovered an historic #6 oil release from abandoned underground storage tanks that were installed in the early 1900's. The issue was presented to city officials, and their design and construction teams. The salient factors during the initial discussions included; holding paramount the health, safety, and welfare of the public, regulatory compliance requirements, and consideration of how this new environmental condition could impact the proposed building and the construction schedule. Because construction delays can add significant unanticipated costs to a construction project, and delay of the opening date of a public school can have wide-spread ramifications, Wheatstone worked together with the municipality and other members of the design team to decide on a plan to address the complex issue in a short time-frame.

 

Initially, the most straightforward approach was to excavate the areas impacted by petroleum as an extension of the building demolition. However, the costs for the earthwork would have been exorbitant (estimated at more then $4,000,000) due to the required size and depth of the excavation (up to 35 feet below ground surface in some areas) which would have required special shoring. A solution was needed to: first, remediate gross contamination left by the petroleum release from historic underground tanks, to protect those that will use the new school in the future; and, second, allow construction of the new school to proceed without costly delays. The solution was a phased approach that included removing the old tanks and accessible contaminated soil after the building demolition, installing a network of seventy injection and recovery wells, conducting an intensive surfactant injection and oil recovery program, conducting a peroxide injection program, and installing belt skimmers to remove residual oil.