UST Closure and PCS Removal
Whatcom Environmental provided a registered Washington State UST Site Assessor to document the removal of a gasoline underground storage tank (UST) from a seafood processing facility in 2008. The processing plant is located on the shoreline of a Native American reservation. Local residents collect clams in nearby tidelands.
During the UST site assessment, petroleum contaminated soil (PCS) was discovered using field screening techniques. Laboratory analysis of the soil confirmed that a release had occurred. Since the release occurred on Native American land, the Environmental Protection Agency (EPA) provided oversight throughout the project. Whatcom Environmental developed and conducted a site remediation Workplan approved by the EPA.
An excessive amount of groundwater had to be removed from the PCS excavation daily. The pit water was temporarily stored in portable storage tanks and treated onsite with an air stripper. Laboratory data indicated that the air stripping process was successful in treating the pit water to acceptable contaminant concentrations for discharge to the sanitary sewer system. Arrangements were made with the local sewer district to dispose of the treated water in their sanitary sewer. Approximately 1.13 million gallons of water were treated onsite during the remedial process.
Excavation of the PCS continued at the site until all field screening and soil sample laboratory data indicated that the soil in place met applicable MTCA Method A target cleanup levels. Approximately 3,300 tons of PCS were excavated and removed from the excavation site to a lined bioremediation cell located north of the UST site. The stockpiled PCS is scheduled for transport and disposal at a licensed landfill in the summer of 2009.
