Artigo Revisado por pares

Electrokinetic-enhanced permanganate delivery and remediation of contaminated low permeability porous media

2017; Elsevier BV; Volume: 113; Linguagem: Inglês

10.1016/j.watres.2017.02.005

ISSN

1879-2448

Autores

Ahmed Ishtiaque Amin Chowdhury, Jason I. Gerhard, D. A. Reynolds, Brent E. Sleep, D. M. O’Carroll,

Tópico(s)

Landfill Environmental Impact Studies

Resumo

Back diffusion of contaminants from low permeability strata has inhibited site remediation and closure due to an inability to deliver remediants into these strata. This study demonstrates the potential of electrokinetics (EK) to significantly reduce back diffusion of chlorinated compounds from low permeability porous media. Experiments were conducted in a two-dimensional sandbox packed with vertical layers of coarse sand and silt contaminated with aqueous trichloroethene (TCE). Three experiments, each approximately 41 days in duration, compared EK-enhanced in situ chemical oxidation (EK-ISCO) to EK or ISCO alone. EK-ISCO successfully delivered the oxidant (permanganate, PM) throughout the silt cross-section while ISCO without EK resulted only in PM delivery to the edges of the silt layer fringes. EK-ISCO resulted in a 4.4-fold reduction in TCE concentrations in the coarse sand compared to a 3.5-fold reduction from ISCO alone. EK-ISCO with a 25 mA current was found to be more effective than with 300 mA current. Overall, this study suggests that electrokinetics coupled with an appropriate in situ remediation technique, such as ISCO, can enhance remediation of lower permeability strata and limit the extent of contaminant back diffusion.

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