Ashby, S. L.. U.S. Army Engineer Waterways Experiment Station, ashbys@exl.wes.army.mil
Faulkner, S. L.. Louisiana State University,
Gambrell, R. P.. Louisiana State University,
Smith, B. A.. Louisiana State University,

 
ASSESSING IRON OXIDATION KINETICS IN RESERVOIR RELEASES
 
Methods for assessing iron oxidation kinetics in reservoir releases were evaluated with laboratory and field studies. Laboratory studies evaluated 1) colorimetric methods for iron speciation, 2) measurements after filtration with various filter pore sizes, 3) effects of oxygen concentration and pH, and 4) differences between simulated reservoir release water and natural surface waters. Field studies evaluated the applicability of colorimetric methods for iron speciation in the release from a reservoir with an anoxic hypolimnion. Oxidation of ferrous iron in laboratory studies indicated little effect of filtration sizes on ferrous measurements, however, greater concentrations were measured in the unfiltered samples, rapid loss of ferrous iron coincident with oxidation, and differences in ferrous iron dynamics in natural waters when compared to observations using simulated reservoir waters. Speciation of iron using ferrozine to determine ferrous iron concentrations, spectrometry to measure total iron concentrations, and calculation of ferric iron by difference was considered to be suitable for assessing reservoir releases. Oxidation rates of ferrous iron in laboratory flumes were greater at pH values near 7 than values near 6. Oxidation of ferrous iron and subsequent transport and deposition in the reservoir tailwater indicated a first order removal process which varied with discharge.
 
Day: Wednesday, Feb. 3
Time: 04:00 - 04:15pm
Location: Sweeney Center
 
Code: SS28WE0400S