Client: Confidential
Location: Wyoming
Project: Environmental Consulting Services
Project Characteristics:
- Subsurface Investigation
- In-Situ Biosparge
- 3D Site Conceptual Model
- Geotechnical Analysis
- NAPL Transmissivity
- Hydrocarbon Fingerprint Analysis
- Remedial Alternative Evaluation
Project Detail:
Ensolum personnel provided environmental consulting services related to the release of natural gas condensate from aboveground storage tanks (AST) at a compressor station. The release was discovered during installation activities of a pipeline approximately 400 feet downgradient of the compressor station in February 2008. Ensolum was retained to investigate the magnitude and extent of petroleum hydrocarbons in soil and groundwater in accordance with the Voluntary Remediation Program, Title 35, Chapter 11, Article 16 of the Wyoming Environmental Quality Act, W.S. § 35-11-1601 et seq. Ensolum’s services include the operation and maintenance of an in-situ biosparge remediation system.
Following the project’s transition in October 2021, Ensolum conducted environmental investigation activities to evaluate the magnitude and extent of petroleum hydrocarbon impacts on soil and groundwater, including light non-aqueous phase liquid (LNAPL). Investigation activities included High-Resolution Site Characterization (HRSC), geotechnical analysis, soil and groundwater sampling for laboratory analyses, LNAPL transmissivity evaluation, and hydrocarbon fingerprinting.
Based on analytical results of the groundwater samples, Ensolum provided justification and received approval from the Wyoming Department of Environmental Quality (WDEQ) to reduce the sampling schedule of 7 monitor wells from quarterly to semi-annual. Ensolum evaluated the performance and implemented modifications to the existing remediation system. These modifications increased the runtime of the remediation system from an average of 140 to 330 days per year.
The results of Ensolum’s HRSC activities demonstrated that the initial hydrocarbon mass was underestimated. Ensolum prepared a cost-benefit analysis, which included additional strategies to achieve the site’s remedial objectives. Ensolum’s recommendation to expand the existing remediation system is projected to reduce the remedial timeframe by 12 years and save the client $1.5M.
