Dataset Information

The Impact of Well-Field Configuration on Contaminant Mass Removal and Plume Persistence for Homogeneous versus Layered Systems.

ABSTRACT: A three-dimensional numerical model was used to simulate the impact of different well-field configurations on pump-and-treat mass removal efficiency for large groundwater contaminant plumes residing in homogeneous and layered domains. Four well-field configurations were tested, Longitudinal, Distributed, Downgradient, and natural gradient (with no extraction wells). The reductions in contaminant mass discharge (CMDR) as a function of mass removal (MR) were characterized to assess remediation efficiency. Systems whose CDMR-MR profiles are below the 1:1 relationship curve are associated with more efficient well-field configurations. For simulations conducted with the homogeneous domain, the CMDR-MR curves shift leftward, from convex-downward profiles for natural gradient and Longitudinal to first-order behaviour for Distributed, and further leftward to a sigmoidal profile for the Downgradient well-field configuration. These results reveal the maximum potential impacts of well-field configuration on mass-removal behaviour, which is attributed to mass-transfer constraints associated with regions of low flow. In contrast, for the simulations conducted with the layered domain, the CMDR-MR relationships for the different well-field configurations exhibit convex-upward profiles. The nonideal mass-removal behaviour in this case is influenced by both well-field configuration and back diffusion associated with low-permeability units.

SUBMITTER: Guo Z

PROVIDER: S-EPMC5944865 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

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The Impact of Well-Field Configuration on Contaminant Mass Removal and Plume Persistence for Homogeneous versus Layered Systems.

Guo Zhilin Z Brusseau Mark L ML

Hydrological processes 20171107 26

A three-dimensional numerical model was used to simulate the impact of different well-field configurations on pump-and-treat mass removal efficiency for large groundwater contaminant plumes residing in homogeneous and layered domains. Four well-field configurations were tested, Longitudinal, Distributed, Downgradient, and natural gradient (with no extraction wells). The reductions in contaminant mass discharge (CMDR) as a function of mass removal (MR) were characterized to assess remediation eff ...[more]

PMID: 29755199

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Project description:Contaminant elution and tracer (CET) tests are one method for characterizing the impact of mass transfer, transformation, and other attenuation processes on contaminant transport and mass removal for subsurface systems. The purpose of the work reported herein is to explore specific well-field configurations for improving CET tests by reducing the influence of preferential flow and surrounding-plume effects. Three injection-extraction well configurations were tested for different domain conditions using a three-dimensional numerical model. The three configurations were the traditional configuration with a single pair of injection-extraction wells, modified configuration I with one extraction well located between two injection wells, and modified configuration II with two pairs of injection-extraction couplets (one nested within the other). Elution curves for resident contaminant and breakthrough curves from simulated tracer tests were examined for specific landmarks such as the presence and extent of steady-state (relatively high concentrations) and asymptotic (asymptotic decrease to low concentrations) phases, as well as distinct changes in slope. Temporal-moment analysis of the breakthrough curves was conducted to evaluate mass recovery. Effective diffusion coefficients were obtained by fitting selected functions to the elution curves. Based on simulation results for a homogeneous domain, full isolation of the inner extraction well from the surrounding plume was obtained for the modified configuration II, whereas the extraction wells are impacted by the surrounding plume for the other two configurations. Therefore, configuration II was used for additional simulations conducted with layered and heterogeneous domains. Tracer-test simulations for homogeneous and layered domains indicate 100% mass recovery for the inner extraction well. For the heterogeneous domain, decreasing the distance between the inner injection-extraction well couplet and adjusting the pumping-rate distribution between the two extraction wells increased the mass recovery from 69% to 99%.

Dataset Information

The Impact of Well-Field Configuration on Contaminant Mass Removal and Plume Persistence for Homogeneous versus Layered Systems.

Publications

The Impact of Well-Field Configuration on Contaminant Mass Removal and Plume Persistence for Homogeneous versus Layered Systems.

Similar Datasets

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