Science Inventory

Peroxone Activated Persulfate Oxidation of 1,4-Dioxane under Column Scale Conditions

Citation:

Cashman, M., R. Ball, T. Lewis, AND T. Boving. Peroxone Activated Persulfate Oxidation of 1,4-Dioxane under Column Scale Conditions. JOURNAL OF CONTAMINANT HYDROLOGY. Elsevier Science Ltd, New York, NY, 245:103937, (2022). https://doi.org/10.1016/j.jconhyd.2021.103937

Impact/Purpose:

Groundwater contaminated with 1,4-Dioxane (dioxane) is difficult to degrade using conventional remediation technologies. One innovative remediation strategy is to pump oxidant directly into the contaminated groundwater. While oxidants have been proven to effectively remediate dioxane plumes, most exisiting studies focus on oxidation in scenarios that do not mimic environmental conditions. This research uses a packed sand column saturated with aqueous dioxane to simulate a contaminated groundwater plume. Oxidant is injected into the flowpath of the column to study how different oxidant concentration and injection schemes affect dioxane degredation.

Description:

The research presented herein investigates a peroxone activated persulfate (PAP) oxidant, commercialized under the trade name OxyZone®, and its effects on 1,4-Dioxane (dioxane) contaminated water under column scale conditions in the presence of porous material. There is a limited understanding of the underlying processes that govern PAP oxidation, including the oxidation rates in the presence of aquifer material, and how these reactions proceed once the oxidant is injected into a contaminant plume. Initial batch experiments with porous material (e.g. sand) provided data on the reaction rates of dioxane oxidation as a function of the oxidant: contaminant ratio. The observed degradation rates were approximately 4 times lower than those reported for aqueous solutions containing no porous media. Subsequent column experiments simulated two PAP injections schemes along the flowpath of a dioxane plume to study if the injection of one oxidant slug may yield different results than injecting the same oxidant volume at two separate locations. The injection of one oxidant slug was found more effective, resulting in near complete destruction of dioxane over a prolonged time at a rate more than an order of magnitude greater than in the two-slug injection scenario. Tracer test results suggest that the prolonged oxidant reactivity was in part caused by the high density of the injected oxidant solution. Overall, the results underline the importance of accounting for the properties of both the oxidant solution and the porous material when considering the injection of PAP oxidant into an impacted aquifer.