LNAPL remediation requires understanding oil refinery history, knowing how to work within current-day operational constraints, and expertly applying the latest science. Oil refining in the modern era dates back to the mid-19th century. Many facilities have been built, rebuilt, and expanded several times to accommodate different product demand and evolving refining technology over this 150-year time period.
Here are a few of the challenges related to the historical nature of refineries that require an experienced team to successfully recover LNAPL:
- Variable composition of LNAPL poses different remedial challenges. Older LNAPLs tend to be more viscous or weathered and are typically hard to extract, while fresh fuels often have larger extents due to higher mobility. When older and newer materials comingle, specialized remedial approaches typically need to be leveraged.
- Groundwater levels are often more variable than at other sites. In addition to the typical seasonal and long-term level fluctuations from climate, refineries have multiple water sources and large differences in use over time that have raised and lowered water levels, which can leave more trapped or stranded pockets of LNAPL at refineries that are less accessible to recovery efforts.
- Dense development poses access limitations. The location of aboveground structures and below ground obstructions at refineries often limits access for recovery points.
- Safety requirements take precedence over remediation. Process hazards within an active refinery are paramount, and often limit site access and restrict use of some viable remedial approaches.
Optimizing Remediation Efforts and Saving Money
Our remediation specialists have had success internationally using an approach that leverages traditional LNAPL extraction scenarios, augmented where practical, with technologies from other engineering disciplines. Some innovative Langan approaches include the removal of LNAPL via mobile vacuum enhanced solutions, which allows for a focused remedial approach without a large capital investment, and utilizing “air-lifting” for deep and submerged vertical zone treatment, as typically used for development of deep water wells.
LNAPL remediation requires more than the latest technology. A successful effort must leverage proactive regulatory programs centered around risk-based criteria, extraction practicability discussions, and evaluation and documentation of immobility―while still being focused on the needs of the client. For example, eliminating the LNAPL that accumulates in wells and causes the biggest perception concerns can reap big benefits for clients.
“Our hybrid approach to LNAPL recovery utilizing both innovative and tested methods, delivers remedial solutions with minimized disturbance to ongoing operations. Also, our fit-for-purpose strategies and regulatory advocacy results in desired business outcomes, meaning the main objective―closures,” says John Loeffel, Langan LNAPL Remediation Specialist.
Time and cost savings are achieved by confirming the source and long-term fate of hydrocarbon impacts, focusing on an end goal determined through revised conceptual modeling, limiting installation of permanent systems or new wells, and receiving stakeholder “buy-in” before commencing an extraction plan. A successful remediation team understands the challenges of refinery work and is focused on delivering a safe, effective solution that delivers on the client’s objectives.