Handbook of Solvents - George Wypych - ChemTech - Ventech!

1624 Barry J. Spargo, James G. Mueller
Figure 23.2.6. GCW process diagram. Effective hydrocarbon stripping in the water column is observed in these
systems using a vacuum extraction. A circulation cell is created by directional flow of water in the vertical direction
creating a capture zone extending several meters from the well. In addition a bioreactor (high surface area bacterial
biofilm) can be used in the system to degrade low volatile contaminants [Adapted from Bernhartt et al., U.S. Patent
5,910,245, 1999]
more information on other GCW systems and their various modes of operation see Mueller
et al. 30 and Allmon et al. 31
Modifications of the technology have evolved as promising solutions for in situ
remediation, source management, and/or accelerated recovery of phase-separated hydrocarbons.
In each of these applications, however, success requires that the GCW zone of influence
(ZOI) be validated. Accurate information on the direction and velocity of
groundwater flow is equally important because it determines the rate of transport of contaminants
being released or treated in the sub-surface. Toward this end, pressure transducers,
conservative dye tracers, and in situ permeable flow sensors have been used to validate theoretical
predictions of flow fields and the corresponding ZOI. The resulting information is
then used to reassess the model and make operational changes to the system in order to meet
clean-up goals and objectives.
23.2.3.1.1 Case study - GCW recovery of creosote, Cabot/Kopper’s Superfund
Site, Gainesville, FL
This site is a former pine tar and charcoal generation facility and a active wood treatment facility.
Creosote used in the wood treating operation is the primary HC. The soil is 93% sand
with some silt and clay. Remedial investigation results indicated that ground water in the
shallow aquifer (10 to 23 ft below ground) had been impacted. Horizontal and vertical con-