EGU2020-21203
https://doi.org/10.5194/egusphere-egu2020-21203
EGU General Assembly 2020
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

The effect of clay tortuosity on contaminant plume persistence

changmin kim1 and minjune yang2
changmin kim and minjune yang
  • 1Pukyong National Univ., University, earth environmental system science, Korea, Republic of (changmin_kim@pukyong.ac.kr)
  • 2Department of Earth and Environmental Sciences, Pukyong National University, Busan 48513, South Korea (minjune@pknu.ac.kr)

The presence of contaminated aquitards has been recognized as one of the main obstacles that hamper the successful aquifer restoration and the forward and back diffusion processes were known as the primary mechanism of solute exchange between the aquifer-aquitard system. In this study, a series of 2-D flow chamber experiments were conducted using 1 g/L of bromide solution as a non-reactive tracer to evaluate back diffusion phenomenon and plume tailing behavior based on different clay types (kaolinite, montmorillonite, and bentonite). In order to determine appropriate values for clay tortuosity, simulated effluent concentrations using 1-D analytical solutions were compared to the measured effluent concentrations. The best fits were found with for bentonite, for kaolinite, and The bentonite tortuosity value close to 1 indicates that the solute flowpath is similar to the aquitard straight-line distance under the saturated condition. Simulation results using the calculated tortuosity showed that bromide effluent concentration due to back diffusion from the montmorillonite layer decreased to 3 orders of magnitude below the initial concentration after 60 days of back diffusion. For bentonite, calculated effluent concentrations decreased to 3 orders of magnitude below the initial concentration after 230 days of back diffusion. These results suggest that the aquitard with higher tortuosity has more capability to sustain long-term plume persistence for non-reactive contaminants and more potential risks as secondary contaminant sources.

How to cite: kim, C. and yang, M.: The effect of clay tortuosity on contaminant plume persistence, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21203, https://doi.org/10.5194/egusphere-egu2020-21203, 2020.

Displays

Display file