An Evaluation of Factors Affecting the Solidification/Stabilization of Heavy Metal Sludge

Solidificationstabilization of hazardous waste involves mixing the waste with a binder material to enhance the physical properties of the waste and to immobilize contaminants that may be detrimental to the environment. Many hazardous wastes contain materials that are known to inhibit the setting and strength development properties of cement and pozzolan binding agents commonly used in solidificationstabilization processes. This study presents the results of an evaluation into the effects of ten interfering substances oil, grease, lead, copper, zinc, sodium hydroxide, sodium sulfate, phenol, trichloroethylene, and hexachlorobenzene on the physical and contaminant mobility properties of a solidifiedstabilized heavy metal sludge. Three binder materials Portland cement, limefly ash, and cementfly ash were used to solidifystabilize a synthetic metal plating waste sludge containing substantial concentrations of four metals cadmium, chromium, nickel, and mercury. The effects of these interfering materials were evaluated using five physical tests unconfined compressive strength UCS, cone index, bulk density, wetdry cycling, and permeability. Contaminant leaching properties were evaluated using the U.S. Environmental Protection Agencys Extraction Procedure test. Microchemical micromorphological analyses were also performed on the treated sludges.... Cement, Metals, Fixation, Pozzolan, Hazardous waste, Solidification, Heavy metals, Stabilization, Interferences.