Environmental Engineering & Science

Wasatch Reopens Former Gas Station Release Site

Wasatch Environmental provided environmental services for the former Family Foods and Fuel gasoline station site, which was acquired as part of a freeway expansion project. This gas station was in operation from 1968 to 2010. Several underground storage tanks (USTs) had been removed, and others had been granted temporary closure status by the Utah Division of Environmental Response and Remediation (DERR) in 2010. The facility had three releases that were reported to the DERR, all of which were granted regulatory closure, with significant residual soil and groundwater impacts allowed to remain in place.

To facilitate road expansion that would include part of the former gas station property, Wasatch performed subsurface investigation to evaluate current site conditions and to obtain sufficient information that would support reopening the closed status of the release and provide access to additional Petroleum Storage Tank funds.

Wasatch supervised the removal of five USTs, product piping, and dispenser islands on the property, which allowed for corrective action by over-excavation to begin in the UST basin area. Excavation was guided by field observations of grey to black staining, petroleum hydrocarbon odors, free-product leaching from soils, and field screening.

During over-excavation of the UST basin area, groundwater was encountered at an average depth of 7 feet. Free-product was observed leaching into the excavation from the walls of the excavation. It was initially abated with sorbent pads and sorbent booms, and then aeration equipment was deployed as well. As the excavation area expanded, a vacuum truck was used to skim the free-product and surface water.

A hard layer of slag of 1 to 3 feet thick was encountered at a depth of approximately 3 to 4 feet. The slag was encountered throughout most of the central, western, and southern portions of the excavation. As the soil below the slag was excavated, deeper soil contamination below the water table that contained free product could be removed.

During the excavation work, a number of subsurface features, including a septic tank, drains, and subsurface drain pipes, were also removed and disposed of off-site to facilitate complete and thorough remediation of the site. With Wasatch overseeing the removal of these subsurface features, excavation of contaminated soil and replacing with clean fill, and removal of free product, the former gas station site was fully remediated and ready for use.