GZA performed turnkey remediation of a former manufactured gas plant (MGP) site where soil impacted by coal tar had contaminated groundwater. Regulatory compliance, environmental impact during construction, and cost effectiveness were key client considerations.


After GZA’s site investigation, contaminant delineation, and remedial alternative evaluation, the selected remedy was in-situ stabilization/solidification (ISS) of contaminated soils approximately 3-15 feet below existing ground surface. GZA hired multiple subcontractors and performed full-time construction management services on Site that included  hazardous materials abatement, building demolition, and implementation of ISS. Cost-saving measures included re-use of uncoated crushed building materials to limit off-site disposal and excavation and stockpiling of surficial soil to re-use as backfill. The EPA’s Environmental Footprint Analysis (SEFA) methodology indicated that the ISS reduced carbon dioxide equivalents by a factor of approximately seven compared to excavation, removal, and thermal desorption. 


From site investigation and evaluation of remedial alternatives to hiring and managing subcontractors to implement the remedy, GZA provided the broad range of environmental, engineering, and construction management services to successfully and cost-effectively remediate the site, navigate the regulatory process, address stakeholder concerns, and moderate the client’s environmental footprint.