Simplified contaminant source depletion models as analogs of multiphase simulators

Basu, N. B.; Fure, A. D.; Jawitz, James W.

doi:10.1016/j.jconhyd.2008.01.001

Cited by 27 publications

(31 citation statements)

References 48 publications

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“…Concomitantly, the reduction in mass flux achieved with a specific level of source-zone mass removal (or mass depletion) is a key metric for evaluating the effectiveness of a source-zone remediation effort. Several approaches, based on “source-depletion” models or simple “mass-removal” functions, have been employed for characterizing the relationship between mass flux reduction and mass removal (e.g., Enfield et al, 2002; Rao et al, 2002; Parker and Park, 2004; Falta et al, 2005; Jawitz et al, 2005; Basu et al, 2008a; Brusseau et al, 2008; DiFilippo and Brusseau, 2008; Maji and Sudicky, 2008; Zhang et al, 2008). …”

Section: Introductionmentioning

confidence: 99%

“…This approach has been applied in several studies during the past decade (e.g., Rao et al, 2002; Brooks et al, 2004; Zhu and Sykes, 2004; Falta et al, 2005; Basu et al, 2008a, 2008b; Brusseau et al, 2008; DiFilippo and Brusseau, 2008; Kaye et al, 2008, Maji and Sudicky, 2008; Parker et al, 2008, Chen and Jawitz, 2009, DiFilippo et al, 2010, Marble et al, 2010). The parameter n defines the specific mass-flux-reduction/mass-removal relationship, and is a lumped-process term that incorporates the impact of organic-liquid distribution, flow-field dynamics (e.g., changes in relative permeability), and mass-transfer processes.…”

Section: Introductionmentioning

confidence: 99%

“…One example is using the ganglia-to-pool (GTP) ratio to define organic-liquid distribution (e.g., Lemke et al, 2004; Christ et al, 2006; Lemke and Abriola, 2006; Suchomel and Pennell, 2006; Basu et al, 2008a, Brusseau et al, 2008, Christ et al, 2009). The GTP is the ratio of the volume of organic liquid present at or below residual saturation divided by the volume present at saturations greater than residual saturation.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, other potential system-indicator parameters include global organic-liquid saturation, source-length/system-length ratio, and source-area/system-area ratio (cross-sectional areas). Statistical measures of organic-liquid saturation and permeability distributions have also been employed as system-indicator parameters (e.g., Mayer and Miller, 1996; Jawitz et al, 2005, Saenton and Illangasekare, 2007, Basu et al, 2008a, 2008b, DiFilippo et al, 2010). …”

Section: Introductionmentioning

confidence: 99%

“…The robustness of simple mass-removal functions and system indicator parameters for predicting mass-flux behavior is anticipated to be generally limited, particularly for complex systems (e.g., Christ et al, 2006, Basu et al, 2008a; Brusseau et al, 2008, DiFilippo and Brusseau, 2008; Marble et al, 2008; DiFilippo et al, 2010). However, such approaches may have use for example in providing a “first-order” approximation of mass-flux behavior.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Assessment of a simple function to evaluate the relationship between mass flux reduction and mass removal for organic-liquid contaminated source zones

DiFilippo

Brusseau

2011

Journal of Contaminant Hydrology

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The efficacy of a simple mass-removal function for characterizing mass-flux-reduction/mass-removal behavior for organic-liquid contaminated source zones was evaluated using data obtained from a series of flow-cell experiments. The standard function, which employs a constant exponent, could not adequately reproduce the non-singular (multi-step) behavior exhibited by the measured data. Allowing the exponent to change as a function of mass removal (as the organic-liquid distribution and relative permeability change) produced non-singular relationships similar to those exhibited by the measured data. Four methods were developed to characterize the variability of the exponent through correlation to measurable system parameters. Key factors that mediate the magnitude of mass flux (dilution and source accessibility) were accounted for using measures of source zone cross-sectional area, ganglia-to-pool (GTP) ratio, and relative permeability. The two methods that incorporated only the ganglia-to-pool ratio produced adequate simulations of the observed behavior for early stages of mass removal, but not for later stages. The method that incorporated parameters accounting for the source zone cross-sectional area (i.e., measure of system dilution) and source accessibility (GTP ratio and relative permeability) provided the most representative simulations of the observed data.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Assessment of a simple function to evaluate the relationship between mass flux reduction and mass removal for organic-liquid contaminated source zones

DiFilippo

Brusseau

2011

Journal of Contaminant Hydrology

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Comparison of upscaled models for multistage mass discharge from DNAPL source zones

Kokkinaki

Werth

Sleep

2014

Water Resources Research

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Analytical upscaled models that can describe the depletion of dense nonaqueous phase liquids (DNAPLs) and the associated mass discharge are a practical alternative to computationally demanding and data-intensive multiphase numerical simulators. A major shortcoming of most existing upscaled models is that they cannot reproduce the nonmonotonic, multistage effluent concentrations often observed in experiments and numerical simulations. Upscaled models that can produce multistage concentrations either require calibration, which increases the cost of applying them in the field, or use dual-domain conceptual models that may not apply for spatially complex source zones. In this study, a new upscaled model is presented that can describe the nonmonotonic, multistage average concentrations emanating from complex DNAPL source zones. This is achieved by explicitly considering the temporal evolution of three source zone parameters, namely source zone projected area, the average of local-scale DNAPL saturations, and the average of local-scale aqueous relative permeability, without using empirical parameters. The model is evaluated for two real and twelve hypothetical centimeter-scale complex source zones. The proposed model captures the temporal variations in concentrations better than an empirical model and a dual-domain ganglia-to-pool ratio model. The results provide evidence that effluent concentrations downgradient of DNAPL source zones are controlled by the evolution of the aforementioned macroscopic parameters. This knowledge can be useful for the interpretation of field observations of effluent concentrations downstream of DNAPL source zones, and for the development of predictive upscaled models. Advances in DNAPL characterization techniques are needed to quantify these macroscopic parameters that can be used to guide DNAPL remediation efforts.

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Predicting DNAPL mass discharge and contaminated site longevity probabilities: Conceptual model and high‐resolution stochastic simulation

Koch

Nowak

2015

Water Resources Research

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Improper storage and disposal of nonaqueous-phase liquids (NAPLs) has resulted in widespread contamination of the subsurface, threatening the quality of groundwater as a freshwater resource. The high frequency of contaminated sites and the difficulties of remediation efforts demand rational decisions based on a sound risk assessment. Due to sparse data and natural heterogeneities, this risk assessment needs to be supported by appropriate predictive models with quantified uncertainty. This study proposes a physically and stochastically coherent model concept to simulate and predict crucial impact metrics for DNAPL contaminated sites, such as contaminant mass discharge and DNAPL source longevity. To this end, aquifer parameters and the contaminant source architecture are conceptualized as random space functions. The governing processes are simulated in a three-dimensional, highly resolved, stochastic, and coupled model that can predict probability density functions of mass discharge and source depletion times. While it is not possible to determine whether the presented model framework is sufficiently complex or not, we can investigate whether and to which degree the desired model predictions are sensitive to simplifications often found in the literature. By testing four commonly made simplifications, we identified aquifer heterogeneity, groundwater flow irregularity, uncertain and physically based contaminant source zones, and their mutual interlinkages as indispensable components of a sound model framework.

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Simplified contaminant source depletion models as analogs of multiphase simulators

Cited by 27 publications

References 48 publications

Assessment of a simple function to evaluate the relationship between mass flux reduction and mass removal for organic-liquid contaminated source zones

Assessment of a simple function to evaluate the relationship between mass flux reduction and mass removal for organic-liquid contaminated source zones

Comparison of upscaled models for multistage mass discharge from DNAPL source zones

Predicting DNAPL mass discharge and contaminated site longevity probabilities: Conceptual model and high‐resolution stochastic simulation

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