ARCHIVED REPORTS XR0003281 - Laserfiche WebLink

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3.5 Soil Reductant Demand (SRD) An effort was made to estimate the SRD for Fe(II) and Cascade° by preparing a serves of vials containing soil and reductant, then measuring the amount of reductant remaining over time Neither effort yielded quantifiable results, though useful, qualitative Information was obtained The concentration of Fe(Il) over time is shown in Figure 5 Fe(H) decreased rapidly within the first 11/z hours, then declined relatively slowly over 14 days By Day 14, 3% of the Fe(II) (15 mg/L) still remained The amount of Fe(II) consumed after 1-1/2 hours was approximately 600 mg Fe(II)/kg soil, while 970 mg Fe(Il)/kg soil were consumed by Day 14 However, in the GWS High Fe test (Section 3 2), only about 300 mg Fe/kg soil was consumed in 24 hours This difference may have been due to the different soil to liquid ratios used, which may have affected that rate at which pH increased and Fe(II) was oxidized to Fe(HI) The amount of Cascade° remaining could not be quantified Efforts to measure absorbance were unsuccessful due to rapid oxidation of Cascade° to elemental sulfur, which interfered with the measurement However, qualitative observations were made The aqueous phase was initially yellow and had a strong sulfide odor These characteristics were still present at 11/2 hours However, by Day 14, the aqueous phase was clear and colorless and no odor was present in either the water only test or water and soil test Since the rate of oxidation of Cascade® is strongly dependent upon the amount of oxygen present and the degree of mixing, it is difficult to determine the amount of Cascade® that will be consumed by soil In addition, any measurement obtained in a laboratory would probably only be a very rough estimate of what would be observed in the field due to procedural differences between the field and the laboratory PRIMA Environmental 13 Eval of Reductants January 19,2005 ATC-Diamond Walnut r