Environmental Engineering Reference
In-Depth Information
Figure 15.6.
Scheme of the vacuum extraction process
Schematic cross-sections of three scenarios describing the use of vacuum
extraction for pollution control in a unsaturated zone are shown in Figures 15.7a-c.
The basic scenarios for the flow of volatile compounds through and below polluted
zones are shown in Figures 15.7a and b. The scenario in Figure 15.7c concerns the
case in which the flow of volatile compounds is used to control the pollution in an
environment with low permeability. In this case, the separation of the liquid phase
from the gas phase of the contaminant (i.e. evaporation) is amplified when the air is
sucked towards the extraction shafts. Thus the primary way to decontaminate is
using vapor flow.
Figure 15.7a.
Flow across contaminated zone [JOH 90]
