Mc. Tekrony et al., PILOT-SCALE STUDY OF IN-SITU STEAM EXTRACTION FOR THE RECOVERY OF DENSE NONAQUEOUS PHASE LIQUIDS FROM THE VADOSE ZONE, Journal of environmental science and health. Part A: Environmental science and engineering, 30(4), 1995, pp. 857-873
An environmental audit of a manufacturing site in eastern Pennsylvania
revealed the presence of dense nonaqueous phase liquids (DNAPLs) in t
he vadose zone. The principal analyte detected in this audit was chlor
oform. The current recovery scheme, soil-vapor extraction (SVE), does
not yield a sufficient rate of DNAPL recovery to be economically feasi
ble. A pilot plant was constructed at the site to determine the effect
s of steam injection on DNAPL recovery: Several large, stainless steel
columns were packed with uncontaminated soil from the site and spiked
with chloroform. Tio columns charged with saturated steam at 7.5 psig
yielded 71 and 97% recoveries of the initial chloroform volume after
the addition of less than one pore volume of steam. An average recover
y of 15% was achieved by SVE. Significant levels of chloroform were de
tected in the simulated water table of one of the steam-charged reacto
rs.