FAQs

This easy-to-read brochure offers answers to practical and technical questions about cost-effective management, cleanup or closure of sites with groundwater impacted by light non-aqueous phase liquids (LNAPL), such as petroleum hydrocarbons.

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The Questions:

  • What is LNAPL?
  • What happens when LNAPL is released?
  • What makes cleanup of LNAPL releases so challenging?
  • I can measure LNAPL in a well at my site. Shouldn’t I be able to pump it out of the ground?
  • What do I need to know about a site to estimate whether or not LNAPL is moving in the subsurface?
  • Through time, production from my recovery well has decayed down to levels that are small relative to initial rates. How do I decide when to stop?
  • How can I obtain input to models that estimate LNAPL mobility and recoverability?
  • I’ve collected values for the key input parameters. How do I use the data to estimate LNAPL recoverability and mobility?
  • Under the best of circumstances, I think I can remove 25% of the LNAPL. How can I determine what effect this will have on the dissolved plume over short and long time frames?
  • What are some examples of the site conditions where in situ LNAPL treatment is unlikely to improve groundwater quality or otherwise reduce risk? Conversely, what types of sites are likely to benefit from LNAPL treatment?
  • What conditions drive the need for in situ treatment of LNAPL releases?
  • I’ve read studies about innovative technologies that remove >90% of the LNAPL in a contaminated soil. How are these results important in terms of an overall philosophy towards addressing LNAPL impacted sites?
  • After implementing the best technology, there will still be residual LNAPL in the ground at my site. How can I determine whether vapor migration will be a problem?
  • The work of API and other researchers seems useful when applied to site-specific problems. How does it affect the overall picture of LNAPL management?
  • There seems to be a lot of different regulations, guidelines, and opinions about “How Clean is Clean” when it comes to LNAPL sites. How do we reconcile the policy and technical conflicts and move forward from here?