Antea Group was asked to support the response to a pipeline spill of 20,600 barrels of crude oil in a wheat field in the Great Plains.
Project challenges included a remote location, the need for 24/7 operations through seasonal severe weather for multiple years, the need for immediate mitigation efforts coupled with a transition to a longer-term assessment and site remedy, multiple sub-surface water-bearing zones, and the need for treatment of over 1,200,000 tons of impacted soil through on-site treatment.
The overall project objective was to return the land to agricultural use and prevent any impacts from reaching the groundwater aquifer.
Solution
Antea®Group’s role was to provide immediate mitigation efforts including:
Delineating the extent and magnitude of the release area
Providing design and installation oversight of an interim crude oil collection system
Monitoring well installation, sampling, and potential receptor identification
As the immediate danger subsided, the project shifted to longer-term assessment and remediation. The remedy selected included on-site soil treatment through TDUs. Following successful treatment, the treated soil and previously removed clean overburden was backfilled on-site and a 6-inch topsoil layer was placed.
Antea Group’s support included:
Subsurface investigation using laser-induced fluorescence, Geoprobe, and sonic soil boring equipment
Final remedial design, including procurement plans and bid documents to secure an excavation and TDU contractor
Permitting support and compliance management
Health and safety support, including personnel monitoring
Subcontractor management and oversight
Remedial implementation, including direction of excavation and backfilling activities
Sampling of soil, groundwater, surface water, and soil vapor
Contaminant fate and transport modeling
Data validation and management of more than 4,400 sample results
3D MVS mapping of the spill to drive design, budget, and remedial approach
Groundwater monitoring and production well installation oversight and sampling
Identification and delineation of a historic third-party release adjacent to the project area
Working with regulatory and landowner stakeholders to develop site-specific cleanup goals
Coordination with university agricultural researchers to assist with stakeholder goals
Excavation, treatment, and backfill quantity tracking and reporting
Soil sampling and documentation program for segregating soil and monitoring excavation and thermal treatment activities
Reporting, including annual, semi-annual, and quarterly reports
Post-remediation monitoring plan implementation
Throughout this long-term project, Antea Group demonstrated our attention to safety. From fall of 2013 to date, there have been no Antea Group or subcontractor injuries.
Currently the site has been restored for agricultural use and is undergoing a five-year post-remediation groundwater monitoring program.
Result
Antea Group’s investigation, remedial design, oversight, and management of the project have resulted in successful site restoration. The remedial approach using on-site soil treatment and replacement resulted in minimal off-site waste generation, reduced the need for securing and importing large quantities of replacement soil, and eliminated potential long-term mechanical remediation.
Antea Group’s use of multiple investigation techniques and 3D visualization capabilities resulted in reduced project costs by refining excavation areas and supporting negotiations for alternate site-specific clean-up goals reducing soil treatment volumes. Further cost reductions were realized through the investigation phase using real-time data evaluation, resulting in fewer borings.
Antea Group’s proactive management provided our client with up-to-date information to manage the project’s initial high level of public visibility. Project stakeholder communications supported by Antea Group reduced public visibility and enhanced trust with regulatory stakeholders and property owners.
