The environmental challenges the project presented required a well-planned approach to manage every aspect — from planning to permitting to extensive remediation and closure. Burns & McDonnell took a collaborative approach to creating a Removal Action Plan (RAP) with the Airport Authority and state regulators that included objectives for the management of impacted soils and liquids, along with activities associated with demolition, tank removal, excavation, backfill and site restoration.
Steps within the decommissioning process also required coordination with fuel farm operations due to two interstate petroleum pipeline receipt facilities operated by separate companies responsible for their own demolition.
An airport terminal, public road and parking facilities all remained open during the project without disruption, thanks to ongoing monitoring for any fugitive air emissions during remediation. The team already had developed an AAMP to establish baseline conditions for comparison.
Implementing the RAP began in November 2021, starting with abandoning wells, emptying tanks and transferring fuel to the new facility. Next came demolishing structures, both above and below ground, before excavating and disposing of impacted materials, sampling backfill and bringing in new material for placement, compaction and grading that resulted, ultimately, in site restoration.
The team coupled on-site field screening techniques with quick turns negotiated with a local lab to sample unimpacted and less-impacted soil material so that the material could be beneficially reused as needed for backfill, significantly reducing the amount of landfill waste and corresponding equipment and labor that would have been required to transport it for off-site disposal.
At the airport’s request, soil samples collected from two borrow source sites were analyzed for an extensive list of compounds, including PFAS. Missouri does not currently provide screening levels for PFAS in soils, therefore, the USEPA Regional Screening Levels (RSLs) were used for a comparison of PFAS data. None of the samples exhibited any detections for PFAS-related compounds above laboratory testing limits and the laboratory reporting limits for all PFAS compounds in all samples were below the corresponding USEPA RSLs. Based on the results of soil samples collected, both sites were approved for providing backfill. Any fuel-impacted material was removed.
Concrete from the containment area and surface pavement was processed on-site and also reused as backfill in deeper excavations. Off-site fill dirt located on property owned by the airport was used for the upper portion of backfill.