Ground Water Monitoring and Remediation最新文献

{"title":"Forecasting Groundwater Remediation Timeframes: Site-Specific Temporal Monitoring Results May Not Predict Future Performance","authors":"Thomas E. McHugh,&nbsp;Charles J. Newell,&nbsp;Lila M. Beckley,&nbsp;David T. Adamson,&nbsp;George E. DeVaull,&nbsp;Matthew A. Lahvis","doi":"10.1111/gwmr.12609","DOIUrl":"10.1111/gwmr.12609","url":null,"abstract":"<p>At contaminated sites, groundwater monitoring results are commonly used (quantitatively or qualitatively) to predict remediation timeframes. If results are predictive, then there should be a strong positive correlation between attenuation rates for the first half of a temporal monitoring record and attenuation rates for the second half of the same record. We utilized the GeoTracker database to evaluate the power of historical groundwater monitoring results to predict future attenuation rates. For two data sets (petroleum and chlorinated solvent), we found a small negative correlation between the first-order concentration vs. time attenuation rate observed during the earlier part of the monitoring record and the later part of the monitoring record: benzene—correlation coefficient (r) = −0.11, methyl tert-butyl ether (MTBE)—r = −0.12, trichloroethene (TCE) = −0.12. For each data set, a small negative correlation between the first-order attenuation rate observed during the earlier part of the monitoring record and the later part of the monitoring record was also observed for a subset of monitoring records exhibiting the best model fits (R² &gt; 0.8), a subset with a statistically significant (p &lt; 0.05) positive attenuation rate for the first half of the monitoring record. For the TCE data set, this negative correlation was also observed for a subset of monitoring records with no change in site remedy during the monitoring period (r = −0.22). Our analysis suggests that the historical concentration vs. time attenuation rate for a contaminant at an individual site or monitoring well is a poor predictor of the future rate.</p>","PeriodicalId":55081,"journal":{"name":"Ground Water Monitoring and Remediation","volume":"43 4","pages":"92-103"},"PeriodicalIF":1.9,"publicationDate":"2023-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ngwa.onlinelibrary.wiley.com/doi/epdf/10.1111/gwmr.12609","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135747548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Complex Sites Highlight How Far We Have Come—And How Much Remains to be Done","authors":"J.F. Devlin,&nbsp;Gaisheng Liu,&nbsp;Murray Einarson","doi":"10.1111/gwmr.12606","DOIUrl":"https://doi.org/10.1111/gwmr.12606","url":null,"abstract":"&lt;p&gt;Confucius is credited with saying that life is really simple but we insist on making it complicated. Flip this upside down and we have a quote that might apply to contaminated sites: “Sites are complicated but we insist on making them simple.” A simple site is one that has not been studied. That being said, some sites present more challenges than others, and these are the ones researchers and practitioners have in mind when they talk about “Complex Sites.” The complexity arises from a number of factors that make up the pantheon of reasons simple site investigations or cleanup efforts fail: multiple contaminants, DNAPL presence, heterogeneous sediments that include low-permeability features, fractured rock or karst, fast flow, chemically aggressive groundwater, deep contamination, and the list goes on. In the early days of contaminant hydrogeology, many of these factors were underappreciated or unrecognized for the challenges they presented, and attempts to remediate sites were unsuccessful, to put it kindly. Since the turn of the millennium, the hydrogeological knowledge base has increased substantially, and new technologies and approaches have been introduced to fully remediate or at least significantly mitigate contamination in the subsurface. In this issue of GWMR, several of these technologies and approaches are presented.&lt;/p&gt;&lt;p&gt;Among the challenges that have been taken on are those of proper characterization and conceptual model development. Examples of this are featured in an article on in situ mineral samplers to track abiotic reactions with chlorinated solvents (Divine et al.) and two articles outlining approaches for developing three-dimensional geological and numerical site models (Lefrancois et al.) and modeling of multicomponent NAPL remediation for decision support (Stewart et al). Batch experiments are conducted to study strategies on how to handle mixed contaminants (Gavazza et al.). An insightful case study is presented to demonstrate how soil excavation can be used innovatively to address a multitude of logistical and technical challenges at a brownfield site (Cohen et al.). Articles describing the most recent developments in thermal remediation and electrokinetic treatment are also featured here (Heron et al.; Riis et al.). These are only a few examples of the articles and features presented in this issue.&lt;/p&gt;&lt;p&gt;The ultimate goal of contaminant hydrogeology is to understand the fate and transport of pollutants in groundwater, and to use that understanding to responsibly mitigate the risk these substances pose to humans and the environment. The complexity and dynamic nature of the subsurface constantly presents us with surprises and routinely drives us to come up with innovative solutions—either in the form of a single case workaround, or in the form of a broadly applicable new technology. The articles featured in this issue present a small sampling of that innovation and progress. The problem of complex sites remains a formid","PeriodicalId":55081,"journal":{"name":"Ground Water Monitoring and Remediation","volume":"43 3","pages":"4"},"PeriodicalIF":1.9,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gwmr.12606","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50137049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Complex Brownfields Case Study—The Former Bannister Federal Complex, Kansas City, Missouri","authors":"Harvey A. Cohen,&nbsp;Kevin P. Breslin,&nbsp;Michael T. Rafferty","doi":"10.1111/gwmr.12597","DOIUrl":"https://doi.org/10.1111/gwmr.12597","url":null,"abstract":"<p>In November 2017, 225 acres (91 ha) of the former Bannister Federal Complex (BFC) in Kansas City, Missouri were transferred from the Federal Government to Bannister Transformation &amp; Development, LLC (BTD), for demolition; environmental corrective measures; and preparation of the site for redevelopment. This presented a once-in-a-lifetime opportunity to reconfigure groundwater remedies and address long-standing soil contamination issues. The property included more than 40 previously-identified Solid Waste Management Units, 3.9 million square feet (362,000 m²) of buildings, subsurface utilities dating back to the 1940s, and an active groundwater containment system. Demolition of buildings and installation of an interim groundwater containment system began almost immediately after property transfer. In 2018, BTD substantially modified its project schedule to incorporate the construction of the first new buildings while demolition and remedial activities were ongoing. By October 2020, construction of the first new warehouse commenced while excavation and capping of contaminated soils, installation of a groundwater containment treatment systems, and abandonment of legacy utilities were still underway. Completion of this work, within the originally planned timeframe, was made possible by factors including up-front multi-year funding, early and ongoing engagement of regulators, an extended 3-year due diligence program and planning stage, and establishment of well-defined environmental targets. Both the soil and groundwater remedies were also designed with the flexibility needed to accommodate unknown conditions, changing schedules, and revisions to the regrading and redevelopment plans. This case study highlights key technical and management factors that led to the successful completion of this complex brownfields remediation project.</p>","PeriodicalId":55081,"journal":{"name":"Ground Water Monitoring and Remediation","volume":"43 3","pages":"129-138"},"PeriodicalIF":1.9,"publicationDate":"2023-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50151339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coal Combustion Residuals Regulation","authors":"Charles Job","doi":"10.1111/gwmr.12605","DOIUrl":"https://doi.org/10.1111/gwmr.12605","url":null,"abstract":"","PeriodicalId":55081,"journal":{"name":"Ground Water Monitoring and Remediation","volume":"43 3","pages":"30-32"},"PeriodicalIF":1.9,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50130217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In My Experience: The Lessons from Dispersion—Don't Believe Everything You Read","authors":"John Cherry","doi":"10.1111/gwmr.12603","DOIUrl":"https://doi.org/10.1111/gwmr.12603","url":null,"abstract":"&lt;p&gt;This note is about my experience investigating and thinking about hydrodynamic dispersion, simply known as dispersion. In keeping with the tried and true practice of academic reductionism, I will constrain the discussion to the relatively simple and idealized case of point-source groundwater plumes in granular deposits with the aim of illustrating some persistent myths and insights about this process, which has attracted so much interest over the past several decades. Dispersion is the most enigmatic topic in hydrogeology and for good reason.&lt;/p&gt;&lt;p&gt;To most hydrogeologists, dispersion refers to mixing of solute concentration during transport of the solutes. It occurs at the plume periphery and, in some cases, internally within the plume. The partial differential equation (the advection-dispersion equation… the ADE), on which nearly all mathematical models (analytical and numerical) for representing solute transport and fate in groundwater are based, does not represent fundamentally the way in which advection and mixing happen in the field. This equation can be useful when simulating bulk plume spreading at a specified point in time but is deeply flawed for the intended purpose of representing plume mixing with background groundwater at the field scale. Although, when used carefully, these models can capture the nature of a contaminant plume for particular purposes at a moment in time, they cannot correctly represent the actual processes that govern the evolution of plumes, in the past or future.&lt;/p&gt;&lt;p&gt;The derivation of the ADE is founded on assumptions that cannot be expected to be met for heterogeneous geologic media and all such media in this context are substantially heterogeneous in their hydraulic conductivity distribution. Solute transport is dependent on the velocity field at a fine spatial scale that can be as small as millimeters or centimeters where molecular diffusion, caused by the local concentration gradients, is the process driving mixing with groundwater at lower solute concentration. This scale is too small for measuring the full velocity field and would require frequent temporal measurements for realistic assessment. Hence, the dispersivity values used in advection-dispersion models are bulk &lt;i&gt;black-box&lt;/i&gt; parameters intended to capture the overall effects of the media heterogeneity. But, when viewed in the context of the spatial and temporal scale diffusive mixing, there are important deviations from the assumptions inherent in the derivation of the ADE. This is a serious matter because a common reason to use mathematical models is for realistic representation of the past as a basis for predicting the future. Moreover, the failures of the ADE to accurately represent the processes, limit model usefulness in exploring parameter interdependencies and sensitivities. In essence, what is published in textbooks about these for “transport and fate” models is, at best, misleading and at worst simply wrong. This has been perpetuated ","PeriodicalId":55081,"journal":{"name":"Ground Water Monitoring and Remediation","volume":"43 3","pages":"145-147"},"PeriodicalIF":1.9,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gwmr.12603","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50130216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SERDP & ESTCP Corner: Headlines from the Environmental Restoration Program Area","authors":"Sarah Mass","doi":"10.1111/gwmr.12604","DOIUrl":"https://doi.org/10.1111/gwmr.12604","url":null,"abstract":"In Situ Powdered Activated Carbon Amendments May Limit Contaminant Availability for Biodegradation The use of adsorbent media for in situ sequestration of chemicals of concern in groundwater has increased in recent years. Many technology vendors promote the use of adsorbent amendments such as powdered activated carbon (PAC) or colloidal activated carbon (CAC) in situ to sequester chemicals of concern in groundwater and minimize downgradient transport. Sorption to PAC and CAC are well documented; however, many issues regarding the application of amendments in situ are not well understood. In particular, the interactions between sorbent media and subsurface microbiota are largely unknown. Some technology vendors claim that biodegradation is enhanced with the use of amendments, especially when slowrelease nutrients are included as part of the amendment media, but the validity of those claims has not yet been conclusively demonstrated. It is generally believed that chemicals in groundwater need to be in the aqueous phase to be available for biodegradation. Previous studies have reported decreased biodegradation due to decreased chemical bioavailability for sorbed constituents that are typically able to be biodegraded, including petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), and pesticides. Therefore, it is possible that readily biodegradable compounds may be less available for biodegradation when sorbed to PAC regardless of nutrient availability. In addition, bacterial growth and biofilm formation on granular activated carbon (GAC) is a known problem in the water treatment industry. Bacterial growth can decrease GAC efficacy for chemical adsorption because bacterial growth can reduce the sorption sites available for chemicals. Microbial growth on PAC similarly has the potential to reduce the effective surface area available for chemical sorption. For chemicals such as perfluorooctane sulfonate and perfluorooctanoic acid (PFOA), where sorption is the predominant mechanism for the efficacy of in situ PAC, competition from bacterial growth may be significant. A recently completed SERDP project titled, “Biological Factors Influencing Sorption and Biodegradation of Chemicals of Concern on Particulate/Colloidal Activated Carbon (ER211059),” investigated the interactions between microbiota and PAC. The project team, led by Principal Investigator Dr. Albert Juhasz at the University of South Australia, aimed to answer two main questions: one, are sorbed contaminants available for biodegradation? Two, do bacteria sorbed onto PAC have an impact on sorptive capacity? The team investigated these two questions by constructing flow cells containing model aquifer materials and PAC. The team first performed sorptiondesorptionbiodegradation experiments using phenanthrene, a low molecular weight PAH that is readily biodegraded. The project team added phenanthrene and a Clabeled phenanthrene surrogate to the flow cells until the sorption capacity of th","PeriodicalId":55081,"journal":{"name":"Ground Water Monitoring and Remediation","volume":"43 3","pages":"139-141"},"PeriodicalIF":1.9,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50130133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strategies for Bioremediation of Soil from an Industrial Site Exposed to Chlorinated and Nitroaromatic Compounds","authors":"Natanna Melo,&nbsp;Sofia Pimentel Araújo,&nbsp;Suzana de Paula Queiroz Kraus,&nbsp;Line Lomheim,&nbsp;Paola Barreto Quintero,&nbsp;Elizabeth Erin Mack,&nbsp;Elizabeth A. Edwards,&nbsp;Jim Spain,&nbsp;Savia Gavazza","doi":"10.1111/gwmr.12596","DOIUrl":"https://doi.org/10.1111/gwmr.12596","url":null,"abstract":"<p>As technological advances allow the development of new products, the number of synthetic chemical compounds released into the soil, surface water and groundwater increases, posing a threat to the environment. Therefore, treatability studies to improve bioremediation strategies (biostimulation and bioaugmentation) were applied to samples of soil containing nitro and chlorinated aromatic compounds from a former chemical manufacturing site in Brazil. Native microorganisms were stimulated to degrade compounds including dichloroanilines, dichloronitrobenzenes, 2-chloronitrobenzene, and 1,2-chlorobenzene, through oxygen exposure and pH (6.0-8.4) and moisture content (13-23%) adjustments. For the inoculation of soil samples, a culture enriched from site groundwater was developed. The aeration alone stimulated the indigenous microbes to degrade some of the compounds. However, reinoculation with an enriched culture and moisture content adjustment increased the attenuation rates by 3.6 and 1.4 times, respectively. The pH values in the range of 7.6 and 8.4 seem not to harm microbes' activity and moisture content higher than 16% is recommended to enhance biodegradation. Based on the findings, it is likely that natural attenuation is happening in aerobic zones at the site. Results indicate both bioremediation strategies (biostimulation and bioaugmentation through reinoculation with enriched culture mainly composed of organisms from the <i>Diaphorobacter</i> genus) are promising strategies to enhance bioremediation. However, considering the applicability of the strategies on a field scale, further experiments will broaden the understanding of biodegradability of compounds, such as their inhibitory effects when in higher concentration (&gt;150 mg/kg), individually or combined.</p>","PeriodicalId":55081,"journal":{"name":"Ground Water Monitoring and Remediation","volume":"43 3","pages":"108-120"},"PeriodicalIF":1.9,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50119145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Remediating a PCE Source Area in Clay Using Electrokinetically Enhanced In Situ Bioremediation","authors":"Charlotte Riis,&nbsp;Evan E. Cox,&nbsp;James Wang,&nbsp;David Gent,&nbsp;Martin Brandi Bymose,&nbsp;Dorte Moon Pade","doi":"10.1111/gwmr.12592","DOIUrl":"https://doi.org/10.1111/gwmr.12592","url":null,"abstract":"<p>The success of in situ remediation techniques such as bioremediation and chemical oxidation is often limited by the presence of contaminants in low-permeability silts and clays, as remediation reagents cannot be effectively delivered into these materials to promote and achieve treatment. A novel electrokinetic (EK) technique, referred to as EK-BIO, was demonstrated at full-scale to overcome the limitations of conventional in situ bioremediation with respect to reagent delivery. Electron donor and dehalorespiring bacteria (KB-1®) were effectively and uniformly delivered throughout a tetrachloroethene (PCE) source area in clay till using the EK-BIO technique. Lactate, as electron donor, was effectively delivered through the clay soils over a sustained operational period of 720 days. A one-time bioaugmentation of the treatment area with KB-1® dehalorespiring culture was conducted within the first month of operation. Vinyl chloride reductase functional gene counts increased by several orders of magnitude in treatment area wells, with ensuing PCE dechlorination to ethene and chloride observed at all treatment area wells. Remediation goals for site soil of 10 mg PCE/kg were met within 2 years of system operation. Average soil concentrations in the treatment area were reduced by 98.75% (PCE eq.). Rebound testing 6 months after cessation of EK-BIO operation showed sustained dechlorination and compliance with remedial goals. These results document the first large field-scale remediation of a PCE source area in clay using EK-BIO.</p>","PeriodicalId":55081,"journal":{"name":"Ground Water Monitoring and Remediation","volume":"43 3","pages":"70-78"},"PeriodicalIF":1.9,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50119144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Min-Trap® Samplers to Passively Monitor In-Situ Iron Sulfide Mineral Formation for Chlorinated Solvent Treatment","authors":"Craig Divine,&nbsp;Shandra Justicia-León,&nbsp;Jennifer Martin Tilton,&nbsp;David Liles,&nbsp;Erika Carter,&nbsp;Erik Zardouzian,&nbsp;Katherine Clark,&nbsp;Dora Taggart,&nbsp;David Freedman,&nbsp;Scott LaRaia,&nbsp;Francesca Perrell,&nbsp;Kathleen Gerber","doi":"10.1111/gwmr.12595","DOIUrl":"https://doi.org/10.1111/gwmr.12595","url":null,"abstract":"<p>The objective of this work was to field-demonstrate the Min-Trap® sampler technology, a new in-situ passive monitoring tool that offers distinct advantages for collecting mineralogical data. The Min-Trap consists of a solid porous medium (e.g., silica sand) contained within a water-permeable mesh and support housing that is deployed inside a monitoring well. The porous medium serves as a solid substrate upon which target minerals passively form. Analysis of the sample medium using chemical, microscopic, spectroscopic, or other techniques can provide direct evidence of geochemical conditions and the formation of target minerals in-situ. The abiotic degradation of chlorinated volatile organic compounds via the reducing power stored in reactive minerals (e.g., iron sulfides) is a recognized important process, and Min-Traps are well suited to document the formation of these minerals during remediation. Min-Traps were tested in multiple wells at two field sites undergoing active remediation where reactive iron sulfide minerals were expected to be actively forming. Min-Trap samples were analyzed by a variety of analytical techniques, including total iron, acid volatile sulfide (AVS), chromium extractable sulfide (CrES; also known as chromium reducible sulfur; CRS), weak acid soluble (WAS) iron, strong acid soluble (SAS) iron, and scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDS). The results provided direct verification of iron sulfide minerals in all cases (<i>n</i> = 9) where they were expected or interpreted to be possibly present based on groundwater data. Min-Traps offer the potential for lifecycle cost savings because they do not require the collection of soil core samples, they can aid in better remedy implementation and performance, and they can potentially support earlier transition from active to passive remedy phases.</p>","PeriodicalId":55081,"journal":{"name":"Ground Water Monitoring and Remediation","volume":"43 3","pages":"57-69"},"PeriodicalIF":1.9,"publicationDate":"2023-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50145764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling of Complex, Multi-Component NAPL Remediation for Decision Support","authors":"Lloyd D. Stewart,&nbsp;Jennifer Nyman,&nbsp;Andres E. Prieto-Estrada,&nbsp;Julie C. Chambon,&nbsp;Mark A. Widdowson,&nbsp;Michael C. Kavanaugh","doi":"10.1111/gwmr.12594","DOIUrl":"https://doi.org/10.1111/gwmr.12594","url":null,"abstract":"<p>In situ remediation of nonaqueous phase liquid (NAPL)-impacted sites is difficult and costly. Even with enhancements (e.g., chemical and thermal) and partial NAPL recovery, mass transfer constraints associated with partitioning from residual NAPL typically control the depletion rate of sources and attainment of cleanup goals. Practical methodologies are needed to support strategic evaluation, planning, and implementation of cost-effective remedial approaches that are considered protective. A modeling system averaging over the NAPL-impacted saturated soil volume was developed and demonstrated at the former Williams Air Force Base. The system combines upscaled, physically based mass transfer coefficients for multi-component NAPL dissolution with theoretical enhancements specific to multiple remediation processes. Dissolution increases in the presence of aqueous phase reactions, according to first- or second-order kinetics, by increasing concentration gradients. Slow biological processes are considered first order in modeling natural attenuation and enhanced biological degradation. Fast reactions associated with chemical oxidation are considered second order. These enhancement models are equally applicable to numerical simulations of NAPL remediation. Pump and treat enhances dissolution in proportion to increases in the characteristic velocity associated with dissolution. The demonstration yielded realistic predictions, with greater certainty, for outcomes from of multiple technologies intended to reduce remedial timeframes and life cycle costs. The enhanced dissolution modeling provides a site-specific, quantitative assessment of changes in NAPL source discharge concentration and mass discharge over time for various remedial options that is equivalent to assessments from complex numerical transport models, given typical input data limitations.</p>","PeriodicalId":55081,"journal":{"name":"Ground Water Monitoring and Remediation","volume":"43 3","pages":"45-56"},"PeriodicalIF":1.9,"publicationDate":"2023-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50140967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}