EHS Support serves as the project coordinator, technical director, and subject matter expert for this performing party group implementing a consent decree to investigate, design, and execute a groundwater cleanup for this former hazardous waste and liquid disposal site.
Our experts developed a detailed strategy for project execution, which was integrated into a subsequent order and statement of work. Key objectives involved effective implementation of the work program, closure of select areas, and improved agency recognition of the technical challenges associated with groundwater restoration.
We developed, refined, and updated groundwater flow and transport models, providing an objective tool to facilitate the decision-making process for selection of an updated remedial strategy. The groundwater flow model was extended to include the local watershed in order to eliminate bias from artificially imposed boundaries, with further refinement within the study area. Three solute transport models were calibrated to the USEPA’s approval, which simulated sequentially decaying chlorinated solvents and 1,4-dioxane degradation.
EHS Support’s experts on natural attenuation and bioremediation of emerging contaminant 1,4-dioxane effectively used advanced DNA-based molecular biological tools to document that the 1,4-dioxane plume is protectively controlled by natural systems, so that active remediation of 1,4-dioxane is unnecessary.
Key successes for the group have included:
- Agency reimbursement of group remediation costs up to $12 million.
- Agency agreement that performance goals can be used for shutdown of the active groundwater remedy (performance goals are an order of magnitude higher than the groundwater cleanup goals).
- Closure of unsaturated zone soils within the former disposal areas.
- Closure of activities related to surface water and sediment evaluations.
- Completed timely revision to the conceptual site model to include more robust understanding of complex geology and previously confounding hydraulic mechanisms existing at the site that will play a major role in remedy selection and implementation.
- Agency agreement on the technical limitations and challenges associated with the selected remedy in the 2010 Record of Decision (ROD) amendment at this site.
- Efficient negotiation with agencies related to the administrative settlement agreement to perform a remedial investigation/ feasibility study and the associated statement of work.
- Timely completion of remedial investigation/feasibility study and the associated statement of work that led to sensible proposed plan and amended ROD for implementation by the group.