Environmental Engineering Reference
In-Depth Information
containment typically refers to unimproved containment that does not require a
energy contribution after being set up in order to reach the desired result. Active
systems of containment are typically passive systems that are improved to increase
performance or require additional energy after construction in order to function
correctly. In Europe, passive containment refers to containment systems without
any form of treatment. The term “active containment” is used for the permeable
reactive walls of North America, and does not include “pump and treat” (see Table
15.1).
Category of
technology
Passive or
active
Technique
Example
Confinement
Passive
covering system
traditional covers,
geochemical covers
vertical barriers
watertight molded walls,
sheet piling, biobarriers,
cement-grouted curtains
horizontal barriers
watertightness with
injection of cement grout
Active
Pump and treat
vertical shafts, horizontal
shafts
reactive barrier (low
permeability)
molded walls (improved
sorption)
Treatment
Passive
monitored natural
attenuation
natural biodegradation
reactive wall (high
permeability)
biobarriers, wall with iron
filings (zero valency, Fe
o
)
phytoremediation
plants, trees
Active
inerting
solidification/stabilization,
vitrification
improved extraction
(requires off-site
treatment)
soil flushing, air sparging,
vacuum extraction, air or
vapor injection, radio
frequency heating
biodegradation
bioventing, biosparging,
infiltration galleries,
improved electrokinetics
Table 15.1.
Passive and active categories for containment techniques
and in situ treatment [SHA 00]
To reduce confusion, the term “reactive” is used in Europe instead of the term
“active”; in this case, the reactive barriers or permeable walls are translated like
reactive zones of treatment. Although the distinction between the active and passive
systems of treatment is not always identified, passive treatment typically refers to
treatment systems that clean the soiled medium (for example, subterranean water)
