AKT Peerless was retained by the client to perform UST system closure activities.  Given that shallow groundwater was expected during closure, AKT Peerless also assisted in securing a dewatering/discharge permit from the local authority.  Additionally, the environmental contractor installed metal shoring around the perimeter of the tank pit to prevent any potential collapses/cave-ins to the tank pit itself due to groundwater erosion of the soil and to minimize any potential erosional damage that could affect the adjacent roadways. During the UST closure activities, groundwater was encountered approximately 12 feet deep.  Soil testing beneath the tanks, pump dispensers and system piping were performed following the removal of these components.  Since groundwater was encountered, groundwater samples within the tank pit were also collected and tested. To determine if the soil data met or exceeded the appropriate soil threshold levels, AKT Peerless performed a sensitive receptor survey as part of the UST closure.  Analytical testing indicated that the soil conditions met the applicable soil threshold levels; however, given that the new tanks were much larger and had to be installed within the former tank pit, the tank pit had to be over-excavated an additional 10 feet horizontally and vertically to allow room for three new 20,000-gallon tanks.  Consequently, although the soil met the applicable soil threshold levels, the soil was still contaminated and could not be reused on-site or sold.  As such, AKT Peerless identified several landfill options for the client.  AKT Peerless completed the required waste profile form and waste characterization process in order to get the selected landfill to approve the impacted soil and pea gravel for disposal.  A total of 2,114 tons of impacted soil and pea gravel were disposed at the approved landfill. 

Although groundwater samples collected from the tank pit prior to the over-excavation activities exceeded the applicable standards, AKT Peerless was able to demonstrate that groundwater sampled downgradient to the tank pit and pump dispensers/system piping did not detect petroleum hydrocarbon contamination above the laboratory reporting limits based on a previous Phase II Environmental Site Assessment (Phase II ESA) we conducted before the UST closure work. Therefore, it was concluded that the groundwater contamination was limited to the tank pit.