Passive Soil Vapor Extraction - GSI Environmental Inc.

SRNL-STI-2009-00571Rev. 1FOREWORDEnhanced Attenuation (EA) is a strategy where engineered remediation activitiessupport and extend natural attenuation processes and assures the sustainability of thoseattenuation mechanisms. The Interstate Technology and Regulatory Council (ITRC), anational regulator led organization with the goal of encouraging adoption of usefulinnovativeenvironmental technologies, defined and described EA in a technicalregulatory document published in 2008 (ITRC, 2008). EA supports the transition fromsource and active treatments to monitored natural attenuation and supports the conceptsof treatment trains and combined remedies.There are two general classes of EA applications: 1) those that reduce the release ofcontaminant from a source into the groundwater plume; and 2) those that increase thenatural attenuation capacity in the subsurface. For the most part, the technologies toaccomplish these objectives are already in use as traditional active treatments. In an EAapproach, technologies are deployed to create an environment that will foster atransition to MNA once the active treatment is complete and will sustain and enhanceimportant natural attenuation mechanisms until remediation goals are met.To illustrate EA and encourage broader use of the strategy, several user guides thatdescribe the selection, design and performance of key technologies are now beingdeveloped by the Savannah River National Lab in collaboration with partners. Theseguides provide information to support the implementation of EA as described in the ITRCtechnical regulatory document (ITRC, 2008) and serve as supplementary resources toenvironmental professionals, regulators and managers in developing technically soundplans to clean up contaminated sites.Enhanced Attenuation TechnologiesPassive Soil Vapor Extraction