Case Studies

Case Studies: Soil Remediation

Industrial Petroleum Distributors, Olympia, Washington

AEG removed seven above ground storage tanks and forty 55-gallon drums of toxic chemicals from a former petroleum distribution site in Olympia. The tanks ranged from 19,000 gallons to 49,000 gallons of product and had to be characterized by phase and disposed of appropriately. Additionally, the tanks were perched on top of a 40-foot hill that only had access from the front, a 40-degree slope. AEG built a road to the top of the hill and developed an erosion control plan to control the resulting erosion hazard. Phase II delineation eventually leading to remediation. The site also involves off-site assessment and remediation.

Shop Fast, Independent Remedial Investigation/Site Remediation, Olympia, Washington

AEG provided soil remedial cleanup action at this retail gasoline facility via excavating and removal of 1,600 tons of petroleum contaminated soil. New double-wall fiberglass underground storage tanks were installed at the property. AEG conducted a complete remedial investigation of the property via drilling and installation of monitoring wells on site, offsite upgradient, crossgradient and downgradient of the property. Environmental forensic studies of the petroleum hydrocarbon plume was investigated via a lead isotopic study of groundwater samples collected from the Site and at upgradient, and downgradient monitoring wells for comparison of Pb206/Pb204 ratios and age dating of the hydrocarbon plume. AEG also conducted a pilot soil vapor extraction study to evaluate the technology's potential application as a remedial method for reducing residual gasoline range TPHs in petroleum hydrocarbons impacted soil onsite. For the preliminary soil vapor extraction pilot study, AEG considered the subsurface characteristics of the site including soil permeabilities and it's subsequent relationship to the SVE gas flow rate and spacing of vapor extraction points. These considerations were tailored towards determining the efficiency and applicability of a SVE system. AEG is currently actively working with Toxic Cleanup Program Managers at the State of Washington Department of Ecology's Voluntary Cleanup Program to remediate the Site.

Tony's Short Stop, Independent Remedial Investigation/Site Remediation, Montesano, Washington

AEG is currently providing environmental consulting services at the Tony's Shortstop retail gasoline station. This Site is a part of the State of Washington Department of Ecology's Montesano Groundwater Investigation where the downtown Montesano area has been impacted via gasoline petroleum hydrocarbons and volatile organic compounds (chlorinated solvents) due to former gasoline stations and automotive repair shops. The area's historic underground utilities including storm drains and sewer lines also provide preferential pathways for migration of these constituents of concern as verified by numerous AEG and the State of Washington Department of Ecology Remedial Investigations. The remedial investigation and cleanup action planned for the site and surrounding area are conducted under the Department of Ecology Agreed Order. In addition, AEG actively worked with surrounding property owners in order to obtain Site Access and coordinated subsurface investigation activities with the City of Montesano due to concerns regarding newly installed underground utilities corridors and the areawide petroleum hydrocarbons impacted groundwater. Remedial investigation by AEG has shown that the gasoline petroleum hydrocarbons and volatile organic compounds (chlorinated solvents) plums have commingled as verified by environmental forensic studies. AEG is currently preparing a Feasibility Study and Cleanup Action Plan for the Site in coordination with Toxic Cleanup Program Managers at the State of Washington Department of Ecology's Voluntary Cleanup Program.

FirstChoice, Product Lines Replacement and Independent Remedial Investigation, Buckley, Washington

AEG conducted a helium test on product lines associated with the First Choice retail gasoline station in order to assess the integrity of the product lines. The test indicated that the product lines have leaked. AEG provided oversight to replacement of the product lines where Interim Remedial Action and Site Characterization activities were conducted to evaluate the lateral and vertical extent of gasoline petroleum hydrocarbons impacted soil and groundwater at this facility. Petroleum contaminated soil was excavated and removed below the product lines and at adjoining dispenser islands. Double-wall fiberglass product lines were adjoining dispenser islands. Double-wall fiberglass product lines were replaced. The underground storage tanks turbines were also re-sealed with an epoxy sealant in order to upgrade the underground storage tank system. Perched groundwater at the property seeped into the excavation trench and was pumped and stored in a 5,000-gallon capacity Baker Tank stored onsite during subsurface excavation activities. AEG drilled and installed monitoring wells onsite and at offsite downgradient locales due to concern regarding potential offsite migration of gasoline range petroleum hydrocarbons. Sentinnel (upgradient) monitoring wells were also installed to evaluate groundwater quality at the Site and nearby properties. The site is actively being monitored via quarterly groundwater monitoring and sampling activities. In addition, AEG is currently working on a Cleanup Action Plan for the property.

Kapowsin Grocery, Independent Remedial Investigation & Bioremediation, Graham, Washington

AEG conducted Independent Remedial Investigations at this facility to ascertain the lateral and vertical extent of gasoline range petroleum hydrocarbons impacted soil and groundwater at this Site. Direct push probes were advanced throughout the property to assess the extent of contamination. Soil remedial action via excavation of petroleum contaminated soil adjacent to and downgradient of the Site's dispenser islands were completed. In addition, AEG conducted bioremediation at the property via successive injections of Oxygen Release Compounds (ORC) into the subsurface to expedite the degradation of petroleum hydrocarbons. Quarterly groundwater monitoring and sampling activities were conducted to assess the constituents of concern and their natural attenuation. Detections of previously elevated concentrations gasoline range petroleum hydrocarbon and gasoline constituents (benzene, toluene, ethylbenzene and total xylenes) at concentrations above the State of Washington Department of Ecology Model Toxics Control Act groundwater cleanup Detectable concentrations of these constituents of concern occurred over a one-year period of bioremediation activities. AEG has petitioned the State of Washington Department of Ecology for a No Further Action status at this property. The cleaned-up and No Further Action status for the Site is currently pending.

Summit Retail Center, Remedial Investigation, Puyallup, Washington

AEG is currently conducting remedial investigation at a shopping center where environmental concerns regarding offsite migration of petroleum hydrocarbons, volatile organic compounds, and metals from offsite upgradient and crossgradient businesses onto the shopping center were evaluated. In order to address the Site's environmental concerns, AEG conducted subsurface investigation via the Longstroke Sonic Drilling Rig to be able to conduct continuous geologic logging of all boreholes. Soil samples were collected and submitted for same day turn-aroundtime laboratory analysis of chlorinated solvents to ensure that monitoring wells would be completed within zones that had not been adversely impacted by chlorinated solvents. Monitoring wells were completed in zones of low permeability and therefore greatly minimizes the potential of migration of chlorinated solvents and constituents of concern from shallower depths to confined zones of low permeability soil. The screened interval at all the completed monitoring wells was screened throughout strata of potential concern (i.e., potential zone of permeability‚ÄĒintervening pockets of sand within predominantly silt and clay) and was designed to accommodate the seasonal low water table fluctuations at this area. A limited access Power Push Probe was also used to conduct subsurface investigation within a dry cleaner facility at the shopping center. Boreholes were advanced adjacent to the dry cleaning machine to collect soil and groundwater samples for laboratory analysis. In order to address potential concerns regarding the quality of indoor air, AEG conducted air sampling via Sumas canisters to assess the potential presence of chlorinated solvents at adjoining businesses to the dry cleaner facility.