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U.S. Department of Energy
Office of Scientific and Technical Information

Passive recovery of DNAPL from clayey soil via vertical collection wells

Technical Report ·
OSTI ID:125984
;  [1]
  1. ENSA Environmental, Inc., Brattleboro, VT (United States)
A release of dense non-aqueous phase liquids (DNAPL) from two underground storage tanks (USTs), created a contaminant plume that extended approximately 30 feet into lacustrine sediments comprised mainly of varved clay. Subsurfaces investigations indicated that the release was comprised primarily of the chlorinated solvent Trichloroethene which had migrated horizontally approximately 250 feet cross-gradient to groundwater flow. A relatively narrow zone of free phase product extended from the UST area approximately 150-200 feet along the plume of migration at a depth of 20-30 feet below the ground surface. Since clay varves interconnected by vertical fractures is believed to have facilitated the DNAPL migration, 4{close_quotes} diameter stainless steel collection recovery of 10-20 quarts of DNAPL per each collection event, over a 4 month period supported what is believed to be preferential DNAPL migration. DNAPL recovery continued for a total of 6 months before the point of diminimus return (1-2 quarts/month) resulted in adopting a quarterly recovery schedule. To date, 201 quarts of free phase DNAPL have been recovered. DNAPL mobility, delineation, well installation and collection techniques are discussed. Compared to conventional remediation alternatives, this passive recovery system provides an innovative approach to a difficult and costly problem; recovery of DNAPL isolated within clay.
Research Organization:
National Association of Environmental Professionals, Washington, DC (United States)
OSTI ID:
125984
Report Number(s):
CONF-9506115--
Country of Publication:
United States
Language:
English