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Remediation
Kinds of Remediation Terms modified by Remediation Selected AbstractsCOSMOPOLITANISM, REMEDIATION, AND THE GHOST WORLD OF BOLLYWOODCULTURAL ANTHROPOLOGY, Issue 1 2010DAVID NOVAK ABSTRACT This essay considers the process of remediation in two North American reproductions of the song-and-dance sequence Jaan Pehechaan Ho from the 1965 "Bollywood" film Gumnaam. The song was used in the opening sequence of the 2001 U.S. independent film Ghost World as a familiar-but-strange object of ironic bewilderment and fantasy for its alienated teenage protagonist Enid. But a decade before Ghost World's release, Jaan Pehechaan Ho had already become the lynchpin of a complex debate about cultural appropriation and multicultural identity for an "alternative" audience in the United States. I illustrate this through an ethnographic analysis of a 1994 videotape of the Heavenly Ten Stems, an experimental rock band in San Francisco, whose performance of the song was disrupted by a group of activists who perceived their reproduction as a mockery. How is Bollywood film song, often itself a kitschy send-up of American popular culture, remediated differently for different projects of reception? How do these cycles of appropriation create overlapping conditions for new identities,whether national, diasporic, or "alternative",within the context of transcultural media consumption? In drawing out the "ghost world" of Bollywood's juxtapositions, I argue that the process of remediation produces more than just new forms and meanings of media, but is constitutive of the cosmopolitan subjects formed in its global circulations. [source] REMEDIATION AND LOCAL GLOBALIZATIONS: How Taiwan's "Digital Video Knights-Errant Puppetry" Writes the History of the New Media in ChineseCULTURAL ANTHROPOLOGY, Issue 2 2007TERI SILVIO This article analyzes the Pili International Multimedia Company's "digital video knights-errant puppetry" serials, a popular culture genre unique to Taiwan, to answer two questions. First, how do digital technologies, originally developed to meet the needs of the American military and entertainment industries, become embedded in a different cultural context? Second, how does this embedding allow media technologies to become something through which distinctly local models of globalization itself may be imagined? Analyzing both the style of the serials and the discourse of producers and fans, I argue that new media technologies, despite their foreign origins, may not only be adapted or resisted, but may also come to be imagined as emerging from local aesthetics and local needs. Through the specific ways they utilize both digital and traditional technologies, the Pili producers and fans construct a utopian vision of what globalization might look like if Taiwan were at the center. [source] RECIRCULATING WELLS: GROUND WATER REMEDIATION AND PROTECTION OF SURFACE WATER RESOURCES,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2000Keith W. Ryan ABSTRACT: Several chlorinated solvent plumes threaten the sole-source aquifer underlying the Massachusetts Military Reservation at the western end of Cape Cod. Sensitive surface water features including ponds, cranberry bogs, and coastal wetlands are hydraulically connected to the aquifer. For one of the plumes (CS-10 the original remedy of 120 extraction and reinjection wells has the potential for significant disruption of surface water hydrology, through the localized drawdown and mounding of the water table. Recirculating wells with in-well air stripping offer a cost-effective alternative to conventional pump-and-treat technology that does not adversely affect the configuration of the water table. Pilot testing of a two well system, pumping 300 gpm, showed a capture radius of > 200 feet per well, in-well trichloroethylene (TCE) removal efficiencies of 92 to 98 percent per recirculation cycle, an average of three recirculation cycles within the capture zone, and no measurable effect on water table elevations at any point within the recirculation/treatment zone. During 120 days of operation, the mean concentration of TCE in the treatment zone was reduced by 83 percent, from 1,111 ,g/l to 184 ,g/l. Full-scale design projections indicate that 60 wells at an average spacing of 160 feet, having an aggregate recirculation 11 MGD, can contain the CS-b plume without ground water extraction or adverse hydraulic effects on surface water resources. The estimated capital costs for such a system are about $7 million, and annual operations-and-maintenance costs should be about $1.4 million, 40 percent of those associated with a pump and treat system over a 20-year period. [source] THE FACE OF MONEY: Currency, Crisis, and Remediation in Post-Suharto IndonesiaCULTURAL ANTHROPOLOGY, Issue 1 2009KAREN STRASSLER ABSTRACT In the period of transition following Suharto's resignation as president of Indonesia in 1998, the image of the 50,000Rp bill bearing his face became a visual shorthand for the corruption and abuse of power that had characterized his regime. Accessible, decentralized consumer technologies enabled people to alter money's appearance, transforming it from a fetish of the state into a malleable surface available for popular reinscription. As the medium of money was "remediated",absorbed into other media, refashioned, and circulated along new pathways,it became a means by which people engaged questions of state power, national integrity, political authenticity, and economic relations opened up by the crisis of Reformasi (Reform). The essay argues that remediations of public forms play a crucial role in times of political transition by enabling people to materialize alternative visions of political authority and authenticity. Moreover, remediated forms have become a characteristic modality of political communication in the post-Suharto period under conditions of democratization and an increasingly diversified media ecology. [source] Remediation of sites contaminated by oil refinery operationsENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2006S. Khaitan The oil industry contributes to contamination of groundwater and aquifers beneath refineries and oil terminals. The successful remediation of a contaminated site requires understanding both the hydrogeology and the nature and extent of contamination. The physical,chemical and biological mechanisms that govern contaminant release, transport and fate in soils, sediments, and associated fluid phases must be understood and quantified. In addition, understanding the flow and entrapment of nonaqueous phase liquids (NAPLs) including lighter-than-water nonaqueous phase liquids (LNAPLs) in contaminated aquifers is important for the effective design of the recovery and remediation schemes. Current remedial technologies and risk assessment techniques to remediate former oil refinery sites contaminated by NAPLs are described in this paper. Emphasis is given to the most promising remediation techniques such as pump-and-treat, on-site bioremediation, phytoremediation, in situ soil washing, and thermal-based technologies, such as steam-enhanced extraction. Some enhancements to pump-and-treat techniques such as solvent flushing, polymer enhanced flushing, and air stripping are also discussed. Finally, important risk-based cleanup criteria associated with contaminated soil at refineries are presented. © 2005 American Institute of Chemical Engineers Environ Prog, 2005 [source] Trout density and health in a stream with variable water temperatures and trace element concentrations: Does a cold-water source attract trout to increased metal exposure?ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2009David D. Harper Abstract A history of hard-rock mining has resulted in elevated concentrations of heavy metals in Prickly Pear Creek (MT, USA). Remediation has improved water quality; however, dissolved zinc and cadmium concentrations still exceed U.S. Environmental Protection Agency water-quality criteria. Physical habitat, salmonid density, fish health, and water quality were assessed, and metal concentrations in fish tissues, biofilm, and macroinvertebrates were determined to evaluate the existing condition in the watershed. Cadmium, zinc, and lead concentrations in fish tissues, biofilm, and invertebrates were significantly greater than those at the upstream reference site and an experimental site farther downstream of the confluence. Fish densities were greatest, and habitat quality for trout was better, downstream of the confluence, where water temperatures were relatively cool (16°C). Measures of fish health (tissue metal residues, histology, metallothionein concentrations, and necropsies), however, indicate that the health of trout at this site was negatively affected. Trout were in colder but more contaminated water and were subjected to increased trace element exposures and associated health effects. Maximum water temperatures in Prickly Pear Creek were significantly lower directly below Spring Creek (16°C) compared to those at an experimental site 10 km downstream (26°C). Trout will avoid dissolved metals at concentrations below those measured in Prickly Pear Creek; however, our results suggest that the preference of trout to use cool water temperatures may supersede behaviors to avoid heavy metals. [source] Enhanced Photocatalytic Activity using Layer-by-Layer Electrospun Constructs for Water RemediationADVANCED FUNCTIONAL MATERIALS, Issue 15 2010Jung Ah Lee Abstract Endocrine disruptors such as bisphenol A (BPA) are environmental pollutants that interfere with the body's endocrine system because of their structural similarity to natural and synthetic hormones. Due to their strong oxidizing potential to decompose such organic pollutants, colloidal metal oxide photocatalysts have attracted increasing attention for water detoxification. However, achieving both long-term physical stability and high efficiency simultaneously with such photocatalytic systems poses many challenges. Here a layer-by-layer (LbL) deposition approach is reported for immobilizing TiO2 nanoparticles (NPs) on a porous support while maintaining a high catalytic efficiency for photochemical decomposition of BPA. Anatase TiO2 NPs ,7,nm in diameter self-assemble in consecutive layers with positively charged polyhedral oligomeric silsesquioxanes on a high surface area, porous electrospun polymer fiber mesh. The TiO2 LbL nanofibers decompose approximately 2.2,mg BPA per mg of TiO2 in 40,h of illumination (AM 1.5G illumination), maintaining first-order kinetics with a rate constant (k) of 0.15,h,1 for over 40,h. Although the colloidal TiO2 NPs initially show significantly higher photocatalytic activity (k,,,0.84,h,1), the rate constant drops to k,,,0.07,h,1 after 4,h of operation, seemingly due to particle agglomeration. In the BPA solution treated with the multilayered TiO2 nanofibers for 40,h, the estrogenic activity, based on human breast cancer cell proliferation, is significantly lower than that in the BPA solution treated with colloidal TiO2 NPs under the same conditions. This study demonstrates that water-based, electrostatic LbL deposition effectively immobilizes and stabilizes TiO2 NPs on electrospun polymer nanofibers for efficient extended photochemical water remediation. [source] Inverse Modeling of Coastal Aquifers Using Tidal Response and Hydraulic TestsGROUND WATER, Issue 6 2007Andrés Alcolea Remediation of contaminated aquifers demands a reliable characterization of hydraulic connectivity patterns. Hydraulic diffusivity is possibly the best indicator of connectivity. It can be derived using the tidal response method (TRM), which is based on fitting observations to a closed-form solution. Unfortunately, the conventional TRM assumes homogeneity. The objective of this study was to overcome this limitation and use tidal response to identify preferential flowpaths. Additionally, the procedure requires joint inversion with hydraulic test data. These provide further information on connectivity and are needed to resolve diffusivity into transmissivity and storage coefficient. Spatial variability is characterized using the regularized pilot points method. Actual application may be complicated by the need to filter tidal effects from the response to pumping and by the need to deal with different types of data, which we have addressed using maximum likelihood methods. Application to a contaminated artificial coastal fill leads to flowpaths that are consistent with the materials used during construction and to solute transport predictions that compare well with observations. We conclude that tidal response can be used to identify connectivity patterns. As such, it should be useful when designing measures to control sea water intrusion. [source] Hydraulics of Recirculating Well Pairs for Ground Water RemediationGROUND WATER, Issue 6 2004Article first published online: 9 OCT 200 First page of article [source] Stochastic Cost Optimization of Multistrategy DNAPL Site RemediationGROUND WATER MONITORING & REMEDIATION, Issue 3 2010Jack Parker This paper investigates numerical optimization of dense nonaqueous phase liquid (DNAPL) site remediation design considering effects of prediction and measurement uncertainty. Results are presented for a hypothetical problem involving remediation using thermal source reduction (TSR) and bioremediation with electron donor (ED) injection. Pump-and-treat is utilized as a backup measure if compliance criteria are not met. Remediation system design variables are optimized to minimize expected net present value (ENPV) cost. Adaptive criteria are assumed for real-time control of TSR and ED duration. Source zone dissolved concentration data enabled more reliable and lower cost operation of TSR than soil concentration data, but using both soil and dissolved data improved results sufficiently to more than offset the additional cost. Decisions to terminate remediation and monitoring or to initiate pump-and-treat are complicated by measurement noise. Simultaneous optimization of monitoring frequency, averaging period, and lookback periods to confirm decisions, in addition to remediation design variables, reduced ENPV cost. Results indicate that remediation design under conditions of uncertainty is affected by subtle interactions and tradeoffs between design variables, compliance rules, site characteristics, and uncertainty in model predictions and monitoring data. Optimized designs yielded cost savings of up to approximately 50% compared with a nonoptimized design based on common engineering practices. Significant improvements in accuracy and reductions in cost were achieved by recalibrating the model to data collected during remediation and re-optimizing design variables. Repeating this process periodically is advisable to minimize total costs and maximize reliability. [source] Climate Change, Sustainability, and Ground Water Remediation: The ConnectionGROUND WATER MONITORING & REMEDIATION, Issue 4 2007Scott D. Warner No abstract is available for this article. [source] Discussion of a Comparison of Field Techniques for Confirming Dense Nonaqueous Phase Liquids by Terry W. Griffin and Kenneth W. Watson (2002), Ground Water Monitoring & Remediation, v. 22, no. 2, pages 48,59GROUND WATER MONITORING & REMEDIATION, Issue 2 2003Richard E. Jackson No abstract is available for this article. [source] Discussion/DNAPL Remediation: Which ,New Paradigm' Will Prevail?GROUND WATER MONITORING & REMEDIATION, Issue 3 2002Ground Water Monitoring & Remediation, by Richard E. Jackson (2001), no. , pages 5, v. 2 No abstract is available for this article. [source] Discussion of "Comparison of Conductivity Values Obtained from Aquifer Pumping Tests and Conservative Tracer Tests," by William L. Niemann and Charles W. Rovey II, Ground Water Monitoring & Remediation, v. 20, no. 3, pages 122,128.GROUND WATER MONITORING & REMEDIATION, Issue 3 2001Fred J. Molz III No abstract is available for this article. [source] Remediation of Sea Water Intrusion: A Case StudyGROUND WATER MONITORING & REMEDIATION, Issue 3 2001Ioannis K. Tsanis Sea water intrusion and remediation in the Upper Floridan Aquifer in South Carolina is simulated using the finite-element model SUTRA developed by the U.S. Geological Survey. A sensitivity analysis of the effect of the hydrogeologic parameters on the sea water recharge and seepage velocities is performed. An increase in confining unit and/or in aquifer conductivity results in an increase of the sea water recharge. An increase in aquifer porosity results in a decrease of the sea water recharge. Among the three remedial techniques simulated,reduced aquifer withdrawals, an injection well, and a combined injection and capture well,the reduced aquifer withdrawals and injection well are the best methods for preventing sea water intrusion. [source] Discussion of "Natural Attenuation: A Feasible Approach to Remediation of Ground Water Pollution at Landfills?," by Thomas H. Christensen, Poul L. Bjerg, and Peter Kjeldsen, Ground Water Monitoring & Remediation, v. 20, no. 1, pages 69,77, Winter 2000.GROUND WATER MONITORING & REMEDIATION, Issue 3 2000Michael A. Apgar No abstract is available for this article. [source] Risk-based decision making to manage contaminated sedimentsINTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 1 2006Todd S Bridges Abstract This paper summarizes discussion among the 7 authors who served on an expert panel at the Third Battelle International Conference on Remediation of Contaminated Sediments held in New Orleans, Louisiana, USA, in January 2005. In this article, the authors review how sediment management decisions are currently made and address the question of how management decisions should be made in the future. It is arguably the case that sediment remediation presents greater challenges and more complexity than traditional land-based clean-ups. Although understanding of these challenges and complexities has grown over the last 25 y, there has been, until recently, relatively little innovation in the approaches used to manage the environmental risks posed by contaminated sediments. New methods that facilitate a more rigorous analysis of the multiple criteria considered in decision making have been developed. These methods, collectively known as multicriteria decision analysis (MCDA), coupled with the use of comparative-risk assessment and cost/benefit analysis, are proposed as an effective, efficient, and credible foundation for evaluating remedy alternatives at contaminated sediment sites. [source] Importance of implementation and residual risk analyses in sediment remediationINTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 1 2006Richard J Wenning Abstract Management strategies for addressing contaminated sediments can include a wide range of actions, ranging from no action, to the use of engineering controls, to the use of more aggressive, intrusive activities related to removing, containing, or treating sediments because of environmental or navigation considerations. Risk assessment provides a useful foundation for understanding the environmental benefits, residual hazards, and engineering limitations of different remedy alternatives and for identifying or ranking management options. This article, part of a series of panel discussion papers on sediment remediation presented at the Third International Conference on Remediation of Contaminated Sediments held 20,25 January 2005 in New Orleans, Louisiana, USA, reviews 2 types of risk that deserve careful consideration when evaluating remedy alternatives. The evaluation of remedy implementation risks addresses predominantly short-term engineering issues, such as worker and community health and safety, equipment failures, and accident rates. The evaluation of residual risks addresses predominantly longer-term biological and environmental issues, such as ecological recovery, bioaccumulation, and relative changes in exposure and effects to humans, aquatic biota, and wildlife. Understanding the important pathways for contaminant exposure, the human and wildlife populations potentially at risk, and the possible hazards associated with the implementation of different engineering options will contribute to informed decision making with regard to short- and long-term effectiveness, implementability, and potential environmental hazards. [source] Orthographic analysis of words during fluency training promotes reading of new similar wordsJOURNAL OF RESEARCH IN READING, Issue 2 2007Inez E. Berends Remediation of a serious lack in reading fluency often takes the form of repeated reading exercises. The present study examines whether transfer of training effects to untrained (neighbour) words can be enhanced by training with an orthographic focus as compared with emphasising semantics. The effect of oral versus silent reading during training is studied as well. Two groups of reading-disabled children (mean age=7 years, 11 months) were given repeated reading training with limited exposure duration (350 ms) in which 15 target words were repeated 20 times in exercises focused on either orthography (N=26) or semantics (N=25). The children were required to either read the target words aloud or perform the exercises silently, but this requirement appeared to have no effect on the training results. The results show that untrained neighbour words benefited more from training targets with an orthographic focus than from exercises with a semantic emphasis. [source] The management lessons learned from sediment remediation in the Detroit River , western Lake Erie watershedLAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 3-4 2004John H. Hartig Abstract During the 1970s,1990s, considerable emphasis was placed on minimizing the inputs of polychlorinated biphenyls (PCBs) from active sources. In addition, between 1993 and 2001, , $US130 × 106 was spent for sediment remediation within the western Lake Erie , Detroit River basin. In general, although PCB contamination of the Detroit River and Lake Erie declined significantly between the 1970s and mid-1990s, it has remained fairly stable over the past 10 years. Control of PCBs and other contaminants at their source remains a primary imperative for action. Remediation of contaminated sediments is growing in importance, however, as greater levels of source control are achieved. From a sediment management perspective, it is estimated that between 1993 and 2001 a substantially higher mass of PCBs (over two orders of magnitude higher) was removed as a result of contaminated sediment remediation, as compared to navigational dredging of shipping channels. In addition, there is a strong and compelling rationale for moving expeditiously to remediate severely contaminated sediment while it is still relatively contained in a small geographical area. The cost of not acting in a timely manner might be to exacerbate environmental problems including increased deformities and reproductive problems in wildlife, delayed ecosystem recovery and increased costs, or even preclusion of future sediment remediation. Based on discussions at a United States of America,Canada workshop held in 2002, key management advice includes continued emphasis to be placed on remediating contaminated sediment hot spots (including evaluating the effectiveness of projects), integrated monitoring efforts to be focused on beneficial use restoration and a high priority to be placed on sustaining and building upon modelling efforts, in order to be able to accurately predict and evaluate ecosystem responses to remedial and preventive actions. [source] Network for Environmental Assessment and Remediation (NEAR): Collaborative research between Switzerland, Poland and RomaniaLAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 2 2000R. L. Thomas [source] Genetics and Neuroscience in Dyslexia: Perspectives for Education and RemediationMIND, BRAIN, AND EDUCATION, Issue 4 2007Gerd Schulte-Körne ABSTRACT , Our understanding of the causes of a developmental disorder like dyslexia has received recent input from both neuroscience and genetics. The discovery of 4 candidate genes for dyslexia and the identification of neuronal networks engaged when children read and spell are the basis for introducing this knowledge into education. However, the input from educational practitioners as well as empirical knowledge from research on learning also contribute significantly to our understanding of how children acquire the basic skills for learning to read and spell. It is imperative to merge the knowledge acquired from research in the fields of neuroscience, genetics, and empirical education, as well as to understand how the learning brain and instruction interact. Doing so can be seen as a major step in attaining an optimal approach for teaching, reading, and spelling and for finding the best suited and most effective treatment concepts for dyslexic children and adolescents. [source] Remediation at the Community College: Pressing Issues, Uncertain SolutionsNEW DIRECTIONS FOR COMMUNITY COLLEGES, Issue 117 2002Betsy Oudenhoven Community colleges welcome traditional-age and adult students who are not prepared to do college-level work, but there is a lack of consensus about how they should be assessed, placed, and taught. [source] Successful ISCR-enhanced bioremediation of a TCE DNAPL source utilizing EHC® and KB-1®REMEDIATION, Issue 3 2010James G. D. Peale Remediation of chlorinated solvent DNAPL sites often meets with mixed results. This can be attributed to the diametrically opposed nature of the impacts, where the disparate dissolved-phase plume is more manageable than the localized, high-concentration source area. A wide range of technologies are available for downgradient plume management, but the relative mass of contaminants in a DNAPL source area generally requires treatment for such technologies to be effective over the long term. In many cases, the characteristics of DNAPL source zones (e.g., depth, soil heterogeneity, structural limitations) limit the available options. The following describes the successful full-scale implementation of in situ chemical reduction (ISCR) enhanced bioremediation of a TCE DNAPL source zone. In this demonstration, concentrations of TCE were rapidly reduced to below the maximum contaminant level (MCL) in less than six months following implementation. The results described herein suggest that ISCR-enhanced bioremediation is a viable remedial alternative for chlorinated solvent source zones. © 2010 Wiley Periodicals, Inc. [source] Remediation of chlorinated ethenes, ethanes, and methanes in groundwater using carbon- and iron-based electron donorREMEDIATION, Issue 4 2009Nanjun Shetty Field-scale pilot tests were performed to evaluate enhanced reductive dechlorination (ERD) of dissolved chlorinated solvents at a former manufacturing facility located in western North Carolina (the site). Results of the site assessment indicated the presence of two separate chlorinated solvent,contaminated groundwater plumes, located in the northern and southern portions of the site. The key chlorinated solvents found at the site include 1,1,2,2-tetrachloroethane, trichloroethene, and chloroform. A special form of EHC® manufactured by Adventus Americas was used as an electron donor at this site. In this case, EHC is a pH-buffering electron donor containing controlled release carbon and ZV Iron MicroSphere 200, a micronscale zero-valent iron (ZVI) manufactured by BASF. Approximately 3,000 pounds of EHC were injected in two Geoprobe® boreholes in the saprolite zone (southern plume), and 3,500 pounds of EHC were injected at two locations in the partially weathered rock (PWR) zone (northern plume) using hydraulic fracturing techniques. Strong reducing conditions were established immediately after the EHC injection in nearby monitoring wells likely due to the reducing effects of ZV Microsphere 200. After approximately 26 months, the key chlorinated VOCs were reduced over 98 percent in one PWR well. Similarly, the key chlorinated solvent concentrations in the saprolite monitoring wells decreased 86 to 99 percent after initial increases in concentrations of the parent chlorinated solvents. The total organic carbon and metabolic acid concentrations indicated that the electron donor lasted over 26 months after injection in the saprolite aquifer. © 2009 Wiley Periodicals, Inc. [source] Sustainable soil remediation by refrigerated condensation at sites with "high-concentration" recalcitrant compounds and NAPL: Two case studiesREMEDIATION, Issue 1 2008Lowell Kessel Remediation of recalcitrant compounds at sites with high concentrations of volatile organic compounds (VOCs) or nonaqueous-phase liquids (NAPLs) can present significant technical and financial (long-term) risk for stakeholders. Until recently, however, sustainability has not been included as a significant factor to be considered in the feasibility and risk evaluation for remediation technologies. The authors present a framework for which sustainability can be incorporated into the remediation selection criteria focusing specifically on off-gas treatment selection for soil vapor extraction (SVE) remediation technology. SVE is generally considered an old and standard approach to in situ remediation of soils at a contaminated site. The focus on off-gas treatment technology selection in this article allows for more in-depth analysis of the feasibility evaluation process and how sustainable practices might influence the process. SVE is more commonly employed for recovery of VOCs from soils than other technologies and generally employs granular activated carbon (GAC), catalytic, or thermal oxidation, or an emerging alternative technology known as cryogenic-compression and condensation combined with regenerative adsorption (C3,Technology). Of particular challenge to the off-gas treatment selection process is the potential variety of chemical constituents and concentrations changing over time. Guidance is available regarding selection of off-gas treatment technology (Air Force Center for Environmental Excellence, 1996; U.S. Environmental Protection Agency, 2006). However, there are common shortcomings of off-gas treatment technology guidance and applications; practitioners have rarely considered sustainability and environmental impact of off-gas treatment technology selection. This evaluation includes consideration of environmental sustainability in the selection of off-gas treatment technologies and a region-specific (Los Angeles, California) cost per pound and time of remediation comparisons between GAC, thermal oxidation, and C3,Technology. © 2008 Wiley Periodicals, Inc. [source] Treatment technologies for mercury in soil, waste, and waterREMEDIATION, Issue 1 2007Martha Otto Mercury occurs naturally in the environment and can be found in elemental (metallic), inorganic, and organic forms. Modern uses for mercury include chemical manufacturing, thermometers, and lighting (mercury vapor and fluorescent lamps). The chemical and allied products industry group is responsible for the largest quantity of mercury used in the United States. Mercury, particularly the organic methylmercury form, is a potent neurotoxin capable of impairing neurological development in fetuses and young children and of damaging the central nervous system of adults. Mercury regulations span multiple federal and state environmental statutes, as well as multiple agency jurisdictions. In August 2007, the U.S. Environmental Protection Agency's (US EPA's) Office of Superfund Remediation and Technology Innovation (OSRTI) published a report titled "Treatment Technologies for Mercury in Soil, Waste, and Water." The report identifies eight treatment technologies and 57 projects, 50 of which provide performance data. This information can help managers at sites with mercury-contaminated media and generators of mercury-contaminated waste and wastewater to identify proven and effective mercury treatment technologies; screen technologies based on application-specific goals, characteristics, and costs; and apply experiences from sites with similar treatment challenges. This article provides a synopsis of the US EPA report, which is available at http://clu-in.org/542R07003. © 2007 Wiley Periodicals, Inc., [source] Remediation with cyclodextrin: Recovery of the remedial agent by membrane filtrationREMEDIATION, Issue 3 2007Thomas B. Boving Cyclodextrin-enhanced flushing of contaminants from the subsurface is a promising innovative remediation technology. It will become more economically viable at more sites if methods can be developed to recover and reconcentrate the cyclodextrin solution after it has been flushed through an aquifer. The goal of this study was to determine if membrane technology is capable of meeting that need. Five membranes with different material properties were tested for this purpose in the laboratory. The results of these tests indicate that there are large differences both in the efficiency of these membranes to extract hydroxpropyl-,-cyclodextrin (HPCD) and their stability when exposed to trichloroethylene (TCE) at concentrations near aqueous solubility. Not only does the molecular weigh cutoff (MWCO) of a membrane determine if HPCD can be retained, but crucial selection criteria are the membrane's resistance and compatibility with TCE. Of the five membrane materials tested, only two (polymer composite membrane and polysulfone) met both these requirements. The polymer composite membrane (MPF-44) showed reliable and stable HPCD recoveries (>95 percent) even when exposed to high TCE concentrations. The polysulfone membrane showed high HPCD recoveries, 88.5 ± 0.4 percent to 97 percent ±1 percent for ultrafiltration and nanofiltration membranes, respectively. However, membrane swelling and deterioration became a problem at high TCE concentrations (>1,000 mg/L). These problems diminished when the TCE concentration was less than 1 mg/L. Field tests demonstrated that batch mode treatment by ultrafiltration doubled the cyclodextrin concentration from 5 to 10 percent within three hours at a constant operating pressure of 13 psi. Under continuous single-pass treatment conditions, cyclodextrin concentration also increased, although the rate of increase was much smaller than in batch mode. Overall, these tests showed that cyclodextrin recovery is possible under field conditions. © 2007 Wiley Periodicals, Inc. [source] Utilization of nanoscale zero-valent iron for source remediation,A case studyREMEDIATION, Issue 2 2006Keith W. Henn A pilot-scale study was performed using a palladium-catalyzed and polymer-coated nanoscale zero-valent iron (ZVI) particle suspension at the Naval Air Station in Jacksonville, Florida. A total of 300 pounds of nanoscale ZVI particle suspension was injected via a gravity feed and recirculated through a source area containing chlorinated volatile organic compounds (VOCs). The recirculation created favorable mixing and distribution of the iron suspension and enhanced the mass transfer of sorbed and nonaqueous constituents into the aqueous phase, where the contaminants could be reduced. Between 65 and 99 percent aqueous-phase VOC concentration reduction occurred, due to abiotic degradation, within five weeks of the injection. The rapid abiotic degradation processes then yielded to slower biological degradation as subsequent decreases in -elimination parameters were observed,yet favorable redox conditions were maintained as a result of the ZVI treatment. Post-treatment analyses revealed cumulative reduction of soil contaminant concentrations between 8 and 92 percent. Aqueous-phase VOC concentrations in wells side gradient and downgradient of the source were reduced up to 99 percent and were near or below applicable regulatory criteria. These reductions, coupled with the generation of innocuous by-products, indicate that nanoscale ZVI effectively degraded contamination and reduced the mass flux from the source, a critical metric identified for source treatment. A summary of this project was recently presented at the US EPA Workshop on Nanotechnology for Site Remediation in Washington, D.C., on October 21,22, 2005. This case study supplied evidence that nanoscale zero valent iron, an emerging remediation technology, has been implemented successfully in the field. More information about this workshop and this presentation can be found at www.frtr.gov/nano/index.htm. © 2006 Wiley Periodicals, Inc. [source] Planning-level source decay models to evaluate impact of source depletion on remediation time frameREMEDIATION, Issue 4 2005Charles J. Newell A recent United States Environmental Protection Agency (US EPA) Expert Panel on Dense Nonaqueous Phase Liquid (DNAPL) Source Remediation concluded that the decision-making process for implementing source depletion is hampered by quantitative uncertainties and that few useful predictive tools are currently available for evaluating the benefits. This article provides a new planning-level approach to aid the process. Four simple mass balance models were used to provide estimates of the reduction in the remediation time frame (RTF) for a given amount of source depletion: step function, linear decay, first-order decay, and compound. As a shared framework for assessment, all models use the time required to remediate groundwater concentrations below a particular threshold (e.g., goal concentration or mass discharge rate) as a metric. This value is of interest in terms of providing (1) absolute RTF estimates in years as a function of current mass discharge rate, current source mass, the remediation goal, and the source- reduction factor, and (2) relative RTF estimates as a fraction of the remediation time frame for monitored natural attenuation (MNA). Because the latter is a function of the remediation goal and the remaining fraction (RF) of mass following remediation, the relative RTF can be a valuable aid in the decision to proceed with source depletion or to use a long-term containment or MNA approach. Design curves and examples illustrate the nonlinear relationship between the fraction of mass remaining following source depletion and the reduction in the RTF in the three decay-based models. For an example case where 70 percent of the mass was removed by source depletion and the remediation goal (Cg/C0) was input as 0.01, the improvement in the RTF (relative to MNA) ranged from a 70 percent reduction (step function model) to a 21 percent reduction (compound model). Because empirical and process knowledge support the appropriateness of decay-based models, the efficiency of source depletion in reducing the RTF is likely to be low at most sites (i.e., the percentage reduction in RTF will be much lower than the percentage of the mass that is removed by a source-depletion project). Overall, the anticipated use of this planning model is in guiding the decision-making process by quantifying the relative relationship between RTF and source depletion using commonly available site data. © 2005 Wiley Periodicals, Inc. [source] | ||||||||||||||||||||||||||||||||||