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In-situ treatment of 1,4-dioxane under column scale conditions
Citation:
Cashman, M. AND T. Boving. In-situ treatment of 1,4-dioxane under column scale conditions. Society of Environmental Toxicology North America 41st Annual Meeting, Virtual, Texas, November 15 - 19, 2020.
Impact/Purpose:
Many anthropogenic contaminants are difficult to remediate from groundwater sources. 1,4-dioxane is present in many groundwater plumes and is resistant to most conventional remediation techniques. This research looks at how innovative remediation techniques can be used to degrade 1,4-dioxane in groundwater. These data are helpful for choosing appropriate remediation strategies for groundwater contaminated with 1,4-dioxane.
Description:
1,4-dioxane is a recalcitrant groundwater contaminant present at many industrial sites and resistant to most conventional remediation technologies. In-situ chemical oxidation with peroxone activated persulfate (PAP) is a promising remediation technology, but there is limited understanding of the underlying process that govern PAP oxidation of 1,4-dioxane. This research investigates a PAP oxidant, OxyZone® (EnChem Engineering, Newton, MA), and its effect on 1,4-dioxane contaminated water under column scale conditions in the presence of porous material. Flow-through column-scale experiments were conducted in a sand packed (porosity =29%), 1.5 m column (i.d. 7.7 cm) saturated with an aqueous 1,4-dioxane solution (QIN, Caq=300 μg/L). The effluent concentrations (QOUT) were measured with gas chromatograph mass spectrometry for 1,4-dioxane concentration alongside pH, oxidation reduction potential, and electric conductivity. Multiple experiments were performed to simulate two field scale oxidant injection schemes of (1) one slug of oxidant injection at one location or (2) two slug injection at two locations within the flow field of a 1,4-dioxane plume. The same amount of oxidant was injected in both scenarios. In these column experiments, the oxidation rates varied from 0.08 h-1 to 1.54 h-1 under pseudo-first order conditions and were greatest in the second oxidant injection scheme. These results suggest that field scale in-situ chemical oxidation of 1,4-dioxane in groundwater plumes with PAP is possible.
