• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.185-192
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• 2010

The objective of this study was to investigate the effectiveness of stabilization for army firing range soil highly contaminated with Pb (total Pb: 29,000 mg/kg) using calcined waste oyster shells. The calcination was conducted to activate quicklime from calcite. In order to evaluate the effectiveness of calcination, both natural oyster shells (NOS) and calcined oyster shells (COS) were applied to the Pb contaminated soil. Stabilization was conducted by mixing the contaminated soil with oyster shell media at 5-20 wt% and cured for 28 days. Following 28 days of curing, Pb leachability was measured based on the Korean Standard Test method (0.1 N HCl extraction). The treatment results showed that the COS treatment outperformed the NOS treatment. All of the NOS treatments failed to meet the Korean warning standard of 100 mg/kg. However, the Pb concentrations were significantly reduced to 47 mg/kg and 3 mg/kg upon 15 wt% and 20 wt% COS treatments, respectively which passed the Korean warning standard. Moreover, -#20 mesh materials were more effective than the -#10 mesh materials in effectively reducing Pb leachability. The scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) results indicated that Pb immobilization was strongly linked to Al and Si.