Evaluation of Factors Affecting the Solidification/Stabilization of Heavy MetalSludge

摘要

Solidification/stabilization of hazardous waste involves mixing the waste with abinder 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 solidification/stabilization 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 solidified/stabilized heavy metal sludge. Three binder materials (Portland cement, lime/fly ash, and cement/fly ash) were used to solidify/stabilize 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, wet/dry cycling, and permeability. Contaminant leaching properties were evaluated using the U.S. Environmental Protection Agency's Extraction Procedure test. Microchemical/micromorphological analyses were also performed on the treated sludges.... Cement, Metals, Fixation, Pozzolan, Hazardous waste, Solidification, Heavy metals, Stabilization, Interferences.