This client sells gasoline across Canada. Unfortunately, they had a release at one of their sites (the Site) during 2006 that required significant soil and groundwater remediation and gained the attention of the Ontario Ministry of Environment (MOE).
The Client had hired an environmental consultant who (1) removed two underground storage tanks, (2) removed more than 1,100 metric tonnes of impacted soil, (3) investigated the Site with more than 60 soil borings and monitoring wells, and (4) implemented chemical injection treatments to remediate the groundwater. However, by 2010, there were still some major problems with the Site including MOE requests to:
· Further delineate the extent of impacted soil and groundwater.
· Investigate reported gasoline vapours in, and around, a City sanitary sewer pumping station.
· Report on the progress of the cleanup to background levels.
These requests indicated the MOE knew the remediation was not progressing well. The Client asked The Dragun Corporation to peer review the file and “right the ship.” Following our peer review, the remediation outlook was a lot brighter.
· First, we re-evaluated the existing groundwater quality and water table elevation data and demonstrated that there were actually two distinct releases of gasoline. One of the releases was clearly from another property, clearly older, and clearly not the responsibility of the Client.
· Second, we conducted a focused Site investigation to clarify the complex, transient groundwater flow, obtain additional data to delineate the older release on the Client’s Site, and evaluate the issue of vapours in the sewers. We needed to add just 13 strategically placed monitoring wells to solve the problem.
· Third, we met with the MOE to explain our findings. The MOE agreed (1) the Client did not need more delineation, (2) we could decommission about half of the monitoring wells, and (3) if the groundwater conditions we reported continued, the Site could be closed.
· After one more monitoring event, the MOE agreed with our conclusion that no further action was needed at the Site. We decommissioned the remaining monitoring wells and were completely finished at the Site in about two years.