Perhaps the most unique application of cement in waste
management is for solidification/stabilization (S/S) treatment of
waste. S/S treatment of waste involves mixing cement into contaminated
media or waste to immobilize contaminants within the treated material.
By mixing portland cement into a waste containing
free liquids, the waste gains physical integrity or become more
solid. The chemical properties of hydrating portland cement are
used to lower the solubility of toxic contaminants in the waste
and is some cases, to also lower the toxicity of a hazardous constituents.
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S/S is used to treat industrial waste to make it safe
for land disposal. S/S is also used to treat contaminated soil,
sediment or sludge at clean-up (remediation) sites. At remediation
projects, S/S treatment can be applied to a variety of contaminated
media (ex. soil and sediment) with a variety of contaminants (ex.
heavy metals, PCBs, and oil). S/S treatment can be applied to material
excavated from the site or treatment of media in place (in-situ).
In-situ treatment can have the added benefit of improving soil conditions
for construction of structures and pavements.
S/S treatment technology contributes to "Green
Remediation" and the sustainable development of a contaminated
property. While immobilizing hazardous constituents, the technology
can also improve the construction properties of the treated materials,
enabling reuse. The technology can also alleviate the concerns of
surrounding communities that are often associated with the off-site
transportation and disposal of contaminated materials. Finally,
the technology contributes to the conservation of landfill capacity,
replacement fill, and fuel used in transportation with the associated
air pollutants and green house gases.
EPA has identified S/S treatment as Best Demonstrated
Available Treatment Technology (BDAT) for many Resource Conservation
and Recovery Act (RCRA) hazardous wastes. According to the EPA,
solidification/stabilization (S/S) is the most frequently selected
treatment technology for controlling the sources of environmental
contamination at Superfund program sites. Over 23% of selected source-control
remedies for these sites include the use of S/S. Sources at these
sites are often contaminated soil or sediment.
There are many advantages to using portland cement
as a S/S binding reagent. First of all, portland cement is manufactured
to specification, which ensures uniformity.
Also, its performance is proven and well-documented
It has been used to treat waste in the U.S since the 1950's. Since
then portland cement has been used to treat the greatest variety
of waste than any other reagent.
And finally, cement is readily available in
all parts of U.S. and Canada. It is economical and can be purchased
in small or bulk quantities. S/S Applications:
S/S Technical Resources
- Brownfields Clean-up and redevelopment
of contaminated industrial and commercial sites
- Superfund Sites Federal program
to clean up releases of hazardous substances at abandoned or
uncontrolled hazardous waste sites.
- Radioactive Waste Safe
management and disposal of radioactive waste.
- Federal Facilities Remediation projects conducted by Federal Agencies other than EPA.
S/S Frequently Asked Questions