Environmental Engineering Reference
In-Depth Information
available up to now, it is obvious that the system based on reactive barriers can be
profitable in comparison with other techniques.
Treatment medium
Targeted contaminants
Status of the technology
Iron filings (Fe
o
)
halocarbons
applied commercially
Iron filings (Fe
o
)
reductible metals
on-site demonstration
Heat
metals, acidic waters
in use (mining field)
Precipitation agents
metals
experimental stage
Sorbent agents
metals and organic
products
experimental stage
Reducing agents
reductible metals
on-site demonstration
Table 15.3.
Technologies used for permeable reactive barriers [SHO 96]
15.5. Active treatment
in situ
15.5.1.
Immobilization (inertage) technologies
15.5.1.1.
Solidification/stabilization
The terms “solidification” and “stabilization” are often interchangeable. This
process consists of operating a matrix contaminated as a whole. The physical
characteristics of the polluted zone are thus modified in order to reduce the physical
access of fluids in the ground to the contaminant. It is mainly about reducing
permeability by various means (injection of hydraulic binders, vitrification or
thermal solidification, etc.).
Solidification refers to the process that imprisons waste in a monolithic solid of
high structural integrity. Solidification can refer to a resulting process in a ground
material rather than a monolithic structure. Solidification does not imply a chemical
interaction between the pollutants and the reagents necessarily; solidification can
mechanically lock pollutants in the solidified matrix. The transfer of contaminants is
limited by enormously decreasing the surface exposed to leaching.
Stabilization generally refers to processes that reduce the risk posed by waste by
converting the contaminants into products that are less soluble, motionless and less
poisonous. This is carried out by a chemical reaction that returns the components to
less leachable waste by immobilizing them or reducing their solubility. However,
the physical nature of waste is not necessarily changed.
