TY - JOUR
T1 - Determining the long-term operational performance of pump and treat and the possibility of closure for a large TCE plume
AU - Guo, Zhilin
AU - Brusseau, Mark L.
AU - Fogg, Graham E.
N1 - Funding Information:
This research was supported by the National Institute of Environmental Health Sciences Superfund Research Program [ ES04940 ], and Department of Energy CERC-WET Program . We thank the reviewers for their constructive comments.
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2019/3/5
Y1 - 2019/3/5
N2 - The purpose of this study is to evaluate the impact of heterogeneity on the long-term performance of a large pump-and-treat (PAT) system that has been in operation for 30 years at a site located in Tucson, AZ. A 3D numerical model was developed. Three different concentrations were examined: composite concentration in the influent to the treatment plant, resident concentration in the aquifer, and concentration for downgradient boundary discharge. The time scales needed for concentrations measured in these ways to reach the Maximum Contaminant Levels (MCLs) are significantly different, with ∼125 years required for treatment-plant influent compared to ∼225 years for downgradient boundary discharge and >>227 years (total simulated time) for the resident concentration in the aquifer. These large time scales, compared to 36 years for a hypothetical homogeneous system, demonstrate the significant impacts of permeability heterogeneity on remediation at this site. The possibility of closure of the site was investigated by examining the mass discharge from the site boundary and the concentration rebound after simulating shutdown of the PAT system. The results of this study provide insight on evaluation of closure potential for large, complex contamination sites and a reference on selecting performance metrics for site management.
AB - The purpose of this study is to evaluate the impact of heterogeneity on the long-term performance of a large pump-and-treat (PAT) system that has been in operation for 30 years at a site located in Tucson, AZ. A 3D numerical model was developed. Three different concentrations were examined: composite concentration in the influent to the treatment plant, resident concentration in the aquifer, and concentration for downgradient boundary discharge. The time scales needed for concentrations measured in these ways to reach the Maximum Contaminant Levels (MCLs) are significantly different, with ∼125 years required for treatment-plant influent compared to ∼225 years for downgradient boundary discharge and >>227 years (total simulated time) for the resident concentration in the aquifer. These large time scales, compared to 36 years for a hypothetical homogeneous system, demonstrate the significant impacts of permeability heterogeneity on remediation at this site. The possibility of closure of the site was investigated by examining the mass discharge from the site boundary and the concentration rebound after simulating shutdown of the PAT system. The results of this study provide insight on evaluation of closure potential for large, complex contamination sites and a reference on selecting performance metrics for site management.
KW - Long-term management
KW - Pump and treat
KW - Rebound
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U2 - 10.1016/j.jhazmat.2018.11.057
DO - 10.1016/j.jhazmat.2018.11.057
M3 - Article
C2 - 30476803
AN - SCOPUS:85057098286
SN - 0304-3894
VL - 365
SP - 796
EP - 803
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
ER -