A chlorinated solvent plume is impacting soil, groundwater, and soil vapor in Seattle’s Georgetown neighborhood. Aspect is working on behalf of Art Brass Plating to investigate and cleanup the plume. Our work includes completing the RI, initiating a source control air sparging/soil vapor extraction system, and leading public participation over an approximate six block area. We also monitor and mitigate against vapor intrusion potential in more than 20 neighboring buildings to protect against exposure while groundwater remediation progresses. We negotiated an Agreed Order with Ecology that enables facility-specific investigation and coordinated data sharing with the area potentially liable parties (PLPs).
The Bremerton Gasworks is a former manufactured gas plant located along the Port Washington Narrows in Bremerton. The Gasworks produced fuel gas from about 1930 until 1963. Byproducts of the gas manufacturing process have contaminated soil, groundwater and sediment at the site. Aspect is performing investigation and cleanup activities for Cascade Natural Gas Corporation, who has entered into an Administrative Settlement Agreement and Order on Consent with the US Environmental Protection Agency for the performance of a remedial investigation and feasibility study under CERCLA.
The groundwater beneath an eight-acre shopping center exhibited chlorinated solvent impacts from four different source areas of varying ages.
To sort out the complexities of multiple sources with multiple responsible parties, Aspect hydrogeologists distinguished the relative solvent contribution from each historical source and developed a site conceptual model that was used to reach an equitable cost-sharing agreement. At the same time, our remediation engineers pilot tested an in situ chemical oxidation system for groundwater treatment without disruption to the active retail facility.
The final remediation system treats all source areas through one air sparge and soil vapor extraction (AS/SVE) system consisting of 16 soil-vapor extraction wells and 47 air-sparging wells spread over an acre of the property.