ABSTRACT
About 30% of the Superfund remediation sites used S/S technologies, according to a USEPA report in 1996.
Of all the binders, cementitious materials are the most widely used for S/S. Compared with other technologies, cement-based S/S has the following advantages:
• Relatively low cost • Good long-term stability, both physically and chemically • Good impact and compressive strengths • Documented use and compatibility with a variety of wastes over decades • Material and technology well known • Widespread availability of the chemical ingredients • Nontoxicity of the chemical ingredients • Ease of use in processing (processing normally conducted at ambient
temperature and pressure and without unique or very special equipment) • High waste loadings possible • Inertness to ultraviolet radiation • High resistance to biodegradation • Low water solubility and leachability of some contaminants • Ability of most aqueous wastes to chemically bind to matrix • Relatively low water permeability • Good mechanical and structural characteristics
• Good self-shielding for radioactive wastes • Long shelf life of cement powder • No free water if properly formulated • Rapid, controllable setting, without settling or segregation during cure
“Stabilization” refers to techniques that chemically reduce the hazard potential of a waste by converting the contaminants into less soluble, mobile, or toxic forms. The physical nature and handling characteristics of the waste are not necessarily changed by stabilization.
