Treatment of complex heavy metal wastewater using a multi-staged ferrite process
Journal
Journal of Hazardous Materials
Journal Volume
209-210
Journal Volume
209-210
Pages
379-384
Start Page
379
End Page
384
ISSN
18733336
Date Issued
2012-03-30
Author(s)
Abstract
Complete removal of heavy metal from complex heavy-metal wastewater (CHMW) requires advanced technology. This study investigated the feasibility of a multi-staged ferrite process (MSFP) for treating CHMW, containing Cd, Cu, Pb, Cr, Zn, Ag, Hg, Ni, Sn and Mn. Our experimental results showed that most of the supernatants after conventional single-step ferrite process could conform to the effluent standard of Environmental Protection Administration in Taiwan. However, the sludge could not satisfy the toxicity characteristic leaching procedure (TCLP) limits due to high Cd, Cu, and Pb concentrations. The performance of MSFP in removing heavy metals from wastewater was subsequently investigated and the parameters of three treating steps in MSFP were optimized under 70°C and 90°C at pH 9, and 80°C at pH 10. After the three-staged procedures, all heavy metals in supernatant and sludge could fulfill the contamination levels regulated by law. In addition, the sludge generated from the MSFP was examined by XRD and forms a stable spinel structure, which could be effectively separated by external magnetic field.
Subjects
Complex heavy metal wastewater
Magnetic separation
Multi-staged ferrite process
Type
journal article