Groundwater Remediation Today and Challenges and Opportunities for the Future

Leeson, Andrea; Stroo, Hans F.; Johnson, Paul C.

doi:10.1111/gwat.12039

Cited by 21 publications

(14 citation statements)

References 8 publications

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“…Rough approximations to fractured‐aquifer property distributions and behavior are inadequate to solve many high‐liability problems (e.g., source‐zone contamination, nuclear waste management), resulting in major financial, institutional, and societal burdens—some with time frames estimated in centuries or millennia. Cost estimates in the United States alone exceed $100 billion to close sites with contaminated groundwater—where the most difficult sites to remediate are in fractured aquifers (Ehlers and Kavanaugh ; Leeson et al ; NRC ; NAS ). Leaders in the field advocate research “in developing more ‘surgical’ characterization and remediation methods” to effectively and efficiently remove health and environmental hazards from contaminated fractured sites (Leeson et al ).…”

Section: Introductionmentioning

confidence: 99%

“…Cost estimates in the United States alone exceed $100 billion to close sites with contaminated groundwater—where the most difficult sites to remediate are in fractured aquifers (Ehlers and Kavanaugh ; Leeson et al ; NRC ; NAS ). Leaders in the field advocate research “in developing more ‘surgical’ characterization and remediation methods” to effectively and efficiently remove health and environmental hazards from contaminated fractured sites (Leeson et al ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hydraulic Tomography: 3D Hydraulic Conductivity, Fracture Network, and Connectivity in Mudstone

Tiedeman¹,

Barrash

2019

Groundwater

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We present the first demonstration of hydraulic tomography (HT) to estimate the three‐dimensional (3D) hydraulic conductivity (K) distribution of a fractured aquifer at high‐resolution field scale (HRFS), including the fracture network and connectivity through it. We invert drawdown data collected from packer‐isolated borehole intervals during 42 pumping tests in a wellfield at the former Naval Air Warfare Center, West Trenton, New Jersey, in the Newark Basin. Five additional tests were reserved for a quality check of HT results. We used an equivalent porous medium forward model and geostatistical inversion to estimate 3D K at high resolution (K blocks <1 m3), using no strict assumptions about K variability or fracture statistics. The resulting 3D K estimate ranges from approximately 0.1 (highest‐K fractures) to approximately 10−13 m/s (unfractured mudstone). Important estimated features include: (1) a highly fractured zone (HFZ) consisting of a sequence of high‐K bedding‐plane fractures; (2) a low‐K zone that disrupts the HFZ; (3) several secondary fractures of limited extent; and (4) regions of very low‐K rock matrix. The 3D K estimate explains complex drawdown behavior observed in the field. Drawdown tracing and particle tracking simulations reveal a 3D fracture network within the estimated K distribution, and connectivity routes through the network. Model fit is best in the shallower part of the wellfield, with high density of observations and tests. The capabilities of HT demonstrated for 3D fractured aquifer characterization at HRFS may support improved in situ remediation for contaminant source zones, and applications in mining, repository assessment, or geotechnical engineering.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hydraulic Tomography: 3D Hydraulic Conductivity, Fracture Network, and Connectivity in Mudstone

Tiedeman¹,

Barrash

2019

Groundwater

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“…Groundwater contamination is an environmental imperative in large parts of the world and lackness of available clean water has brought up new challenge to develop quality cost‐effective groundwater remediation techniques (Leeson et al ). During the past few decades, the effective coupled simulation‐optimization (SO) models have been commonly used for optimal groundwater remediation design of pump‐and‐treat (PAT) systems which has been focus on complex condition with multiple conflicting objectives (Cai et al ; Wu et al ; Yang et al ; Mategaonkar and Eldho ; Majumder and Eldho ).…”

Section: Introductionmentioning

confidence: 99%

An Elitist Multiobjective Tabu Search for Optimal Design of Groundwater Remediation Systems

Yang¹,

Wu²,

Wang

et al. 2017

Groundwater

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This study presents a new multiobjective evolutionary algorithm (MOEA), the elitist multiobjective tabu search (EMOTS), and incorporates it with MODFLOW/MT3DMS to develop a groundwater simulation-optimization (SO) framework based on modular design for optimal design of groundwater remediation systems using pump-and-treat (PAT) technique. The most notable improvement of EMOTS over the original multiple objective tabu search (MOTS) lies in the elitist strategy, selection strategy, and neighborhood move rule. The elitist strategy is to maintain all nondominated solutions within later search process for better converging to the true Pareto front. The elitism-based selection operator is modified to choose two most remote solutions from current candidate list as seed solutions to increase the diversity of searching space. Moreover, neighborhood solutions are uniformly generated using the Latin hypercube sampling (LHS) in the bounded neighborhood space around each seed solution. To demonstrate the performance of the EMOTS, we consider a synthetic groundwater remediation example. Problem formulations consist of two objective functions with continuous decision variables of pumping rates while meeting water quality requirements. Especially, sensitivity analysis is evaluated through the synthetic case for determination of optimal combination of the heuristic parameters. Furthermore, the EMOTS is successfully applied to evaluate remediation options at the field site of the Massachusetts Military Reservation (MMR) in Cape Cod, Massachusetts. With both the hypothetical and the large-scale field remediation sites, the EMOTS-based SO framework is demonstrated to outperform the original MOTS in achieving the performance metrics of optimality and diversity of nondominated frontiers with desirable stability and robustness.

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“…Managing sites with contaminated soil and groundwater frequently requires a decision about whether remediation is necessary, and if so, what type of technology is appropriate to address site‐specific risks. Given this, there is considerable interest in understanding how well various treatment technologies will perform, both in terms of making progress toward cleanup objectives and in performing in a cost‐effective manner (Stroo et al ; McDade et al ; McGuire et al ; Triplett Kingston et al ; National Research Council (NRC) ; Leeson et al ). For sites where chlorinated volatile organic compounds (CVOCs) are the primary contaminant, there are a number of widely‐used technologies for in situ treatment of source zone groundwater (NRC ; US EPA ).…”

Section: Introductionmentioning

confidence: 99%

“…This includes enhanced anaerobic bioremediation, chemical oxidation or reduction, and thermal treatment. Most of these technologies are fairly mature in the sense that extensive guidance and vendor support exists for those who wish to implement them (Leeson et al ). There is also a relatively high level of regulatory comfort with these technologies, and one or more is commonly included in feasibility studies for treating CVOCs in groundwater (US EPA ).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Long‐Term Performance and Sustained Treatment at Enhanced Anaerobic Bioremediation Sites

McGuire¹,

Adamson²,

Burcham³

et al. 2016

Groundwater Monitoring Rem

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This study evaluated the long‐term performance of enhanced anaerobic bioremediation (EAB) at chlorinated solvent sites to determine if sustained treatment processes were helping to prevent concentration rebound. A database of groundwater concentration versus time records was compiled for 34 sites, with at least 3 years of posttreatment monitoring data (median = 4.7 years, range = 3.0 to 11.7 years). Long‐term performance was evaluated based on order‐of‐magnitude (OoM) changes in parent compound concentrations during various monitoring periods. Results indicate that, relative to the pretreatment concentration, a median concentration reduction for all 34 sites of 1.0 OoM (90% reduction) was achieved by the end of the posttreatment monitoring period. No rebound was observed at 65% of the sites between the first year of posttreatment monitoring and the final year. During this posttreatment period, Mann‐Kendall trend analysis indicated that the concentration was stable or decreasing at 89% of the sites where a trend could be established (n = 27; 33% decreasing, 56% stable, 11% increasing). Statistical analysis indicates there is no evidence that the distribution of median concentration reductions after the first year of posttreatment monitoring was different than the distribution of median reductions 2 to 11 years later at the end of the monitoring period (p = 0.67). Similarly, statistical analysis indicates that there is no evidence that the distribution of median reductions for a larger set of sites (n = 84) with less than 3 years of posttreatment monitoring data (1.1 OoM; 92% reduction) was different than the distribution of median OoM reductions for the 34‐site dataset with longer monitoring periods (p = 0.80). This suggests that, at a typical site, a 3‐year monitoring period should be sufficient for evaluating performance. The results of this study indicate that, in the long term, after the end of active treatment, sustained treatment processes contribute to relatively modest concentration reductions but do mitigate rebound at the majority of EAB sites.

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Groundwater Remediation Today and Challenges and Opportunities for the Future

Cited by 21 publications

References 8 publications

Hydraulic Tomography: 3D Hydraulic Conductivity, Fracture Network, and Connectivity in Mudstone

Hydraulic Tomography: 3D Hydraulic Conductivity, Fracture Network, and Connectivity in Mudstone

An Elitist Multiobjective Tabu Search for Optimal Design of Groundwater Remediation Systems

Evaluation of Long‐Term Performance and Sustained Treatment at Enhanced Anaerobic Bioremediation Sites

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