A facility owned by a municipal utility provider was used for decades to clean and service electrical equipment, resulting in the release of fuels, industrial solvents, metals, and polychlorinated biphenyls (PCBs). Source areas with dense non-aqueous phase liquids (DNAPL) from solvents, widespread PCBs in soil and sediment, and groundwater impacts at the site were identified.
Assessment and remediation services have been ongoing for several years at the still-active facility, with Golder providing technical continuity and working closely with site personnel to minimise disruption.
A feasibility study prepared by Golder recommended a phased risk-based corrective action strategy. The remedial program has included DNAPL removal, soil and sediment source area removal and capping, and groundwater monitoring. An engineered “cap”, or paved surface that has been installed, will actually increase the area for on-site operations after the remediation is completed.
A turnkey innovative remedial system, consisting of an in-situ thermal conductive heating (TCH), multi-phase extraction and soil vapour extraction system, was designed for the DNAPL source removal.
For removal of PCB-impacted soils, a large-diameter auger (LDA) approach was used to excavate deep soils in a tight work area. This reduced remedial costs and minimised risks of impacts to a neary off-site facility. Golder will also implement groundwater remedial actions as needed.