Immobilization of As and Pb in contaminated sediments using waste resources

Abstract

As and Pb-contaminated sediment obtained from the Nakdong Lake and Yeongsan River in the Republic of Korea was stabilized using a combination of calcined oyster shell (COS), waste cow bone (WCB) and coal mine drainage sludge (CMDS). The effectiveness of the stabilization treatment was evaluated using the Korean Standard Test (KST). The KST tests were performed using 1 N HCl extraction fluid for As and 0.1 N HCl extraction fluid for Pb. Scanning electron microscopy-energy dis- persive X-ray spectroscopy (SEM-EDX) analyses were performed to investigate the mechanism responsible for As and Pb immobilization upon treatment. The treatment results showed that effective stabilization of As and Pb- contaminated sediment was obtained. Specifically, 10 wt% COS-5 wt% CMDS was the best treatment for As immo- bilization and 5 wt% COS-5 wt% WCB was the best treatment for Pb immobilization. The COS-WCB treat- ment outperformed the COS-CMDS treatment in immo- bilizing Pb in the contaminated sediment. SEM-EDX results indicated that Pb immobilization was strongly associated with Ca, Si, Al and P while As immobilization was strongly associated with Fe and O. Therefore, utili- zation of COS, WCB and CMDS is beneficial for the sta- bilization of contaminated sediment.