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HÅLLBAR SANERING
Rapport 5663 - Klorerade lösningsmedel
technologies. Ex situ treatment of the removed contaminants is necessary. The in
situ technologies include:
• Air sparging, where volatile contaminants are stripped from the saturated
zone by air injection
• Soil vapor extraction, where volatile contaminants are extracted from the
vadose zone by application of vacuum
• Multi-phase extraction, which is a combination of soil vapor extraction
and pump and treat, where contaminants are removed from the subsurface
by high vacuum
• In situ flushing, where contaminants are mobilized or dissolved by water
flushing in some cases amended with co-solvents or surfactants
• In situ thermal treatment, that use heat (steam or electric heating) to
facilitate contaminant removal
Physical mass reduction is usually applied for source area remediation. Air
sparging, soil vapor extraction, multi-phase extraction and in situ thermal treatment
based on steam enhanced extraction are mature technologies, while in situ flushing
and in situ thermal treatment based on electrical heating are emerging and, at
present, not used commonly at full scale.
A number of technologies can be applied for in situ destruction of chlorinated
solvents. These technologies generally address contaminants in the saturated zone.
The main technologies are:
• Enhanced in situ bioremediation, that uses either naturally occurring or
introduced microorganisms to degrade target contaminants, often in
combination with the addition of appropriate substrates to enhance the
degradation rate. In most cases anaerobic dechlorination is applied for
chlorinated solvents treatment
• In situ chemical oxidation, that uses oxidants (permanganate, persulfate,
ozone or Fentons reagent) to destroy target contaminants
• In situ metal catalyzed reduction, which uses zero valent iron (granular or
nano- and microscale powder) to catalyze biotic and abiotic degradation
• Phytoremediation, that uses plants to remove and accumulate or destroy
the contaminants
• Monitored natural attenuation, which is a form of long-term monitoring
that is used to document and quantify natural degradation processes
In situ chemical oxidation and in situ metal catalyzed reduction with nano- and
microscale powder are generally used for source area treatment, while the other in
situ destruction technologies are used for plume remediation. However, the use of
enhanced in situ bioremediation for source area treatment is growing. In situ metal
catalyzed reduction with nano- and microscale powder is an emerging technology.
Also phytoremediation is an emerging technology with limited field applications
for chlorinated solvents. The other technologies are mature.
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