Project ExperienceShut Down: Petroleum Contamination Superhighway
CONTAMINANTS OF CONCERN – PETROLEUM HYDROCARBONS
KEY FACTS – AGRICULTURAL DRAIN TILE CREATES PREFERENTIAL FLOW SUPERHIGHWAY
DESCRIPTION OF SITE – LEAKING UNDERGROUND STORAGE TANK (LUST) CONTAMINATION FROM FORMER GAS STATION
The Site is a former petroleum filling station which was found to contain two separate areas with leaking underground storage tanks (LUSTs). Prior to being a filling station, the property was used for agricultural purposes.
A unique challenge associated with the Site was that the lateral distribution of petroleum hydrocarbons detected during the characterization sampling did not correspond to traditional fate and transport models. In other words, the footprint of the petroleum plume was much larger than expected and petroleum impacts were observed to be side-gradient of the known source areas.
Following a review of investigative findings, AcuityES identified that the Site could potentially be remedied through source-area removal followed by monitored natural attenuation (MNA). A Corrective Action Plan (CAP) was prepared and submitted to the State of Indiana.
During removal of petroleum-impacted soil, agricultural drain tiles (formerly used to dewater the farmland) were found to run directly through one of the petroleum impacted areas – creating a superhighway for contaminant preferential flow. AcuityES determined this was the reason for the side-gradient petroleum impacts that were detected hundreds of feet away from the source areas.
AcuityES implemented a surgical approach to remove petroleum impacted soil proximal to the drain tile. Confirmation soil sampling was conducted using rapid laboratory analysis turn times. This rapid analysis resulted in minimal on-Site excavation equipment downtime and greatly reduced off-Site soil transportation and disposal costs.
Following removal of the petroleum impacted soil, AcuityES conducted confirmation groundwater sampling for the MNA assessment. The Site ultimately received closure, with the State providing a determination of No Further Action.
AcuityES aslo helped the client submit the necessary documentation for cost reimbursement from the Indiana Excess Liability Trust Fund (ELTF).