Clients
Case Study
Major South American Bank
High Resolution Site Characterization of a former Aluminium Production Facility (Colombia) now owned by a major bank in support of a land redevelopment project.
The Challenge
A large bank assumed ownership of a former aluminum plant located in Barranquilla, Colombia, with the goal of redeveloping the land for residential and commercial purposes. The site had been unoccupied since 2011, with remaining structures including partially demolished walls and floors, several concrete pits, and subsurface infrastructure. Previous environmental investigations had revealed hydrocarbon and chlorinated solvent contamination in the soil and groundwater at concentrations that could pose an unacceptable risk to the health of future site users. In addition, the groundwater flow from the site was impacting the nearby Río Magdalena.
Our Work
- Assessment & Planning Services
- High-Resolution Site Characterization
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Remediation Alternatives Analysis
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Stakeholder Support
Our Work
To determine what type of remediation plan was needed, we executed a high-resolution site characterization (HRSC) using multiple methods and lines of evidence, including:
- Using high-resolution sensors, including the Optical Imaging Profiler (OIP), Membrane Interface Probe (MIP), and Hydraulic Profiling Tool (HPT), to quickly determine the depth and extent of contamination and the soil stratigraphy.
- Detailed soil sampling and laboratory analyses to accurately quantify contaminants.
- Installation of monitoring wells at boundary locations and at precise intervals to monitor both the existing groundwater condition and to serve as performance monitoring wells for future remediation activities.
- Vertical profiling of soil gas to evaluate potential pathways for vapor contaminants to move from the deeper subsurface to planned occupied buildings. The vapor monitoring points will also facilitate performance monitoring of future bioremediation processes.
The field data results were detailed in 3D models of contaminant plumes, and a refined hydrogeological characterization of the site was created.
Our Investigative Results
- The high-resolution site characterization process revealed several contaminants, primarily petroleum hydrocarbons and chlorinated solvents, in soil and groundwater with significant concentrations in specific areas on the site.
- We quantified the mass of the toxic compounds of interest at 14 tons.
- Most of the compounds were adsorbed in the soil. A smaller portion had dissolved in the surrounding groundwater.
- Analysis of soil samples showed high concentrations of aromatic hydrocarbons (C10-C32) and medium concentrations of aliphatic hydrocarbons (C9-C18).
- Both exceeded reference values in the central area of the site at depths greater than 10 meters with maximum concentrations of 22,000 and 4,220 milligrams per kilogram of soil, respectively.
- Groundwater samples from site monitoring wells showed volatile organic contamination (VOC) concentrations exceeding reference values with concentrations up to 80 micrograms per liter.
Financial Analysis of Remediation Alternatives
Armed with HRSC results, we developed a detailed financial analysis of multiple remedial alternatives. The analysis examined:
- Cost estimates for multiple remediation methods, such as excavation and off-site disposal, on-site chemical oxidation, and monitored natural attenuation.
- Each method was evaluated based on the extent of contamination, the volume of soil and groundwater to be treated, and the length of the remediation process.
- The cost alternatives for remediation ranged from US$2 to $10 million, a significant reduction over previous estimates of US$65 million for complete site remediation.
- Cost-benefit analysis that considered reducing health risks, improving environmental quality, and potential future land use.
- Potential funding sources and budgeting considerations for the remediation project, highlighting the importance of securing adequate funding to ensure the successful implementation of the chosen remediation strategy.
Recommendations and Next Steps
challenges and risks, including:
- Implementing control measures during excavation and remediation efforts
- Continued monitoring and sampling to ensure the effectiveness of remediation efforts
- Using high-resolution site characterization techniques as needed to close any new data gaps during the remediation.
- Ensuring collaboration between various contractors to effectively manage the remediation project in conjunction with site demolish and redevelopment.