• Chlorinated VOCs
• Design and implementation of large-scale thermal treatment system
• Approximately 2,100 pounds of VOC mass removed
• Extensive confirmation soil and soil vapor sampling program
• Achieved remedial goals across the Site
• Protection of buildings, utilities, and neighboring trees
Challenge
Remediation of chlorinated volatile organic compounds (VOCs), within both the vadose and saturated zones, was required at a tightly constrained and high-profile site that included a vacant manufacturing facility, buried abandoned infrastructure, low-permeability soils, and municipal drinking water wells immediately downgradient. The property’s high value created a need for efficient performance compliance and risk characterization to support accelerated redevelopment.
Solution
GZA implemented a remediation strategy (electrical resistance heating, soil vapor extraction, and hydraulic control) with responsibility for design, permitting, construction, operation, and regulatory reporting. The system included over 800 subsurface installations (electrodes, temperature monitoring points and soil vapor extraction wells) and over 10 miles of electrical cabling. Real-time performance monitoring facilitated system optimization, while targeted modifications addressed buried infrastructure and areas requiring additional treatment. To evaluate potential vapor intrusion under future occupancy scenarios, GZA developed a hot soil vapor sampling, analysis, and correction protocol to adjust concentrations to reflect those that would be present under ambient conditions. The remediation achieved the regulatory objectives, removing approximately 2,100 pounds of VOCs.
Benefit
GZA's remediation approach accelerated Site cleanup, reduced long-term environmental liabilities, and achieved regulatory closure. Evaluating potential vapor intrusion prior to Site cooldown (i.e. years) accelerated the sale and redevelopment of the property.