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This article in JEQ

  1. Vol. 43 No. 3, p. 842-850
    Received: Mar 05, 2013
    Published: June 24, 2014

    * Corresponding author(s): ptacek@uwaterloo.ca


Treatment of Dissolved Perchlorate, Nitrate, and Sulfate Using Zero-Valent Iron and Organic Carbon

  1. YingYing Liu,
  2. Carol J. Ptacek * and
  3. David W. Blowes
  1. Dep. of Earth and Environmental Sciences, 200 University Avenue West, Univ. of Waterloo, Waterloo, ON, Canada N2L 3G1


Waters containing ClO4 and dissolved NO3, derived from detonated explosives and solid propellants, often also contain elevated concentrations of other dissolved constituents, including SO42−. Four column experiments, containing mixtures of silica sand, zero-valent Fe (ZVI) and organic C (OC) were conducted to evaluate the potential for simultaneous removal of NO3, SO42− and ClO4. Initially, the flow rate was maintained at 0.5 pore volumes (PV) d−1 and then decreased to 0.1 PV d−1 after 100 PV of flow. Nitrate concentrations decreased from 10.8 mg L−1 (NO3–N) to trace levels through NO3 reduction to NH4+ using ZVI alone and through denitrification using OC. Observations from the mixture of ZVI and OC suggest a combination of NO3 reduction and denitrification. Up to 71% of input SO42− (24.5 ± 3.5 mg L−1) was removed in the column containing OC, and >99.7% of the input ClO4 (857 ± 63 μg L−1) was removed by the OC- and (ZVI + OC)-containing columns as the flow rate was maintained at 0.1 PV d−1. Nitrate and ClO4 removal followed first-order and zero-order rates, respectively. Nitrate >2 mg L−1 (NO3–N) inhibited ClO4 removal in the OC-containing column but not in the (ZVI + OC)-containing column. Sulfate did not inhibit ClO4 degradation within any of the columns.

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