Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Manganese and trace metal removal in successive anaerobic and aerobic wetland environments

Conference ·
OSTI ID:103808
; ;  [1]
  1. Tennessee Valley Authority, Muscle Shoals, AL (United States). Environmental Research Center
Constructed wetlands designed for removal of Fe from acid mine drainage can be an effective technology with removal rates ranging from 10 to 20 g/m{sup 2}/d. Removal of Mn is less effective, especially in the presence of Fe{sup 2+} which readily reduces any oxidized Mn formed. Although not a widespread concern now, removal of trace metals will become increasingly more important in acid mine drainage with imposed discharge limits. A microcosm study was conducted to evaluate the use of anaerobic wetland systems preceding aerobic wetland systems for removal of Mn, Cu, Ni, Zn, and Pb in simulated acid mine drainage that was pretreated by surface-flow aerobic wetlands for Fe removal. Initial concentrations for Mn, Cu, Ni, Pb, and Zn were 20, 2.1, 1.5, 1.9, and 2.1 mg/L, respectively. Each experimental unit consisted of three troughs set in series. The first trough was anaerobic and the last two were aerobic. The anaerobic troughs with organic matter were effective in reducing SO{sub 4}{sup 2{minus}} to S{sup 2{minus}} and producing alkalinity in the range from 80--300 mg/L Production of alkalinity decreased with time and coincided with seasonal decline in water temperature. Manganese removal in the anaerobic systems decreased with time which may have been due to solubilization Of MnCO{sub 3} due to decreased alkalinity. Manganese removal in the reciprocating aerobic cells was quicker than in the nonreciprocating aerobic cells. Removal in the aerated systems appeared to be due to precipitation of Mn oxides. Removal of Cu, Ni, Zn, and Ph was very effective in the anaerobic cells with organic matter and was presumed to be due to precipitation of metal sulfides.
OSTI ID:
103808
Report Number(s):
CONF-950414--
Country of Publication:
United States
Language:
English