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Pore-Water Extraction Scale-Up Study for the SX Tank Farm

Description: The phenomena related to pore-water extraction from unsaturated sediments have been previously examined with limited laboratory experiments and numerical modeling. However, key scale-up issues have not yet been addressed. Laboratory experiments and numerical modeling were conducted to specifically examine pore-water extraction for sediment conditions relevant to the vadose zone beneath the SX Tank Farm at Hanford Site in southeastern Washington State. Available SX Tank Farm data were evaluated to generate a conceptual model of the subsurface for a targeted pore-water extraction application in areas with elevated moisture and Tc-99 concentration. The hydraulic properties of the types of porous media representative of the SX Tank Farm target application were determined using sediment mixtures prepared in the laboratory based on available borehole sediment particle size data. Numerical modeling was used as an evaluation tool for scale-up of pore-water extraction for targeted field applications.
Date: January 15, 2013
Creator: Truex, Michael J.; Oostrom, Martinus; Wietsma, Thomas W.; Last, George V. & Lanigan, David C.
Partner: UNT Libraries Government Documents Department

Remedy Evaluation Framework for Inorganic, Non-Volatile Contaminants in the Vadose Zone

Description: Contaminants in the vadose zone may act as a potential long-term source of groundwater contamination and need to be considered in remedy evaluations. In many cases, remediation decisions for the vadose zone will need to be made all or in part based on projected impacts to groundwater. Because there are significant natural attenuation processes inherent in vadose zone contaminant transport, remediation in the vadose zone to protect groundwater is functionally a combination of natural attenuation and use of other remediation techniques, as needed, to mitigate contaminant flux to groundwater. Attenuation processes include both hydrobiogeochemical processes that serve to retain contaminants within porous media and physical processes that mitigate the rate of water flux. In particular, the physical processes controlling fluid flow in the vadose zone are quite different and generally have a more significant attenuation impact on contaminant transport relative to those within the groundwater system. A remedy evaluation framework is presented herein that uses an adaptation of the established EPA Monitored Natural Attenuation (MNA) evaluation approach and a conceptual model based approach focused on identifying and quantifying features and processes that control contaminant flux through the vadose zone. A key concept for this framework is to recognize that MNA will comprise some portion of all remedies in the vadose zone. Thus, structuring evaluation of vadose zone waste sites to use an MNA-based approach provides information necessary to either select MNA as the remedy, if appropriate, or to quantify how much additional attenuation would need to be induced by a remedial action (e.g., technologies considered in a feasibility study) to augment the natural attenuation processes and meet groundwater protection goals.
Date: May 1, 2013
Creator: Truex, Michael J. & Carroll, Kenneth C.
Partner: UNT Libraries Government Documents Department

Soil Vapor Extraction System Optimization, Transition, and Closure Guidance

Description: Soil vapor extraction (SVE) is a prevalent remediation approach for volatile contaminants in the vadose zone. A diminishing rate of contaminant extraction over time is typically observed due to 1) diminishing contaminant mass, and/or 2) slow rates of removal for contamination in low-permeability zones. After a SVE system begins to show indications of diminishing contaminant removal rate, SVE performance needs to be evaluated to determine whether the system should be optimized, terminated, or transitioned to another technology to replace or augment SVE. This guidance specifically addresses the elements of this type of performance assessment. While not specifically presented, the approach and analyses in this guidance could also be applied at the onset of remediation selection for a site as a way to evaluate current or future impacts to groundwater from vadose zone contamination. The guidance presented here builds from existing guidance for SVE design, operation, optimization, and closure from the U.S. Environmental Protection Agency, U.S. Army Corps of Engineers, and the Air Force Center for Engineering and the Environment. The purpose of the material herein is to clarify and focus on the specific actions and decisions related to SVE optimization, transition, and/or closure.
Date: February 8, 2013
Creator: Truex, Michael J.; Becker, Dave; Simon, Michelle A.; Oostrom, Martinus; Rice, Amy K. & Johnson, Christian D.
Partner: UNT Libraries Government Documents Department

"Innocent Landowners" and "Prospective Purchasers" in the Superfund Act

Description: The Superfund Act contains several devices that eliminate the liability or reduce the transaction costs normally incurred under the Act by persons that acquire contaminated land. This report focuses on three of them, two addressed in the recently enacted brownfields law (P.L. 107-118). The first device is the innocent-landowner defense, available to persons who acquire land after the hazardous substance is put there, and who (among other things) find no contamination before acquisition despite “all appropriate inquiry.” The second device allows use of innocent-landowner status as a basis for early de minimis settlement with EPA. The third exempts the “bona fide prospective purchaser” from “owner” and “operator” liability despite pre-acquisition awareness of contamination on the property, if certain conditions are met.
Date: March 6, 2002
Creator: Meltz, Robert
Partner: UNT Libraries Government Documents Department

Screening of Potential Remediation Methods for the 200-BP-5 Operable Unit at the Hanford Site

Description: A screening-level evaluation of potential remediation methods for application to the contaminants of concern (COC) in the 200-BP-5 Operable Unit at the Hanford Site was conducted based on the methods outlined in the Guidance for Conducting Remedial Investigations and Feasibility Studies under CERCLA Interim Final (EPA 1988). The scope of this screening was to identify the most promising remediation methods for use in the more detailed analysis of remediation alternatives that will be conducted as part of the full feasibility study. The screening evaluation was conducted for the primary COC (potential major risk drivers) identified in the groundwater sampling and analysis plan for the operable unit (DOE/RL-2001-49, Rev. 1) with additions.
Date: September 21, 2006
Creator: Truex, Michael J.; Dresel, P. EVAN; Nimmons, Michael J. & Johnson, Christian D.
Partner: UNT Libraries Government Documents Department

Survey of subsurface treatment technologies for environmental restoration sites at Sandia National Laboratories, New Mexico.

Description: This report provides a survey of remediation and treatment technologies for contaminants of concern at environmental restoration (ER) sites at Sandia National Laboratories, New Mexico. The sites that were evaluated include the Tijeras Arroyo Groundwater, Technical Area V, and Canyons sites. The primary contaminants of concern at these sites include trichloroethylene (TCE), tetrachloroethylene (PCE), and nitrate in groundwater. Due to the low contaminant concentrations (close to regulatory limits) and significant depths to groundwater ({approx}500 feet) at these sites, few in-situ remediation technologies are applicable. The most applicable treatment technologies include monitored natural attenuation and enhanced bioremediation/denitrification to reduce the concentrations of TCE, PCE, and nitrate in the groundwater. Stripping technologies to remove chlorinated solvents and other volatile organic compounds from the vadose zone can also be implemented, if needed.
Date: August 1, 2003
Creator: McGrath, Lucas K.; Ho, Clifford Kuofei & Wright, Jerome L.
Partner: UNT Libraries Government Documents Department

SERDP ER-1376 Enhancement of In Situ Bioremediation of Energetic Compounds by Coupled Abiotic/Biotic Processes:Final Report for 2004 - 2006

Description: This project was initiated by SERDP to quantify processes and determine the effectiveness of abiotic/biotic mineralization of energetics (RDX, HMX, TNT) in aquifer sediments by combinations of biostimulation (carbon, trace nutrient additions) and chemical reduction of sediment to create a reducing environment. Initially it was hypothesized that a balance of chemical reduction of sediment and biostimulation would increase the RDX, HMX, and TNT mineralization rate significantly (by a combination of abiotic and biotic processes) so that this abiotic/biotic treatment may be a more efficient for remediation than biotic treatment alone in some cases. Because both abiotic and biotic processes are involved in energetic mineralization in sediments, it was further hypothesized that consideration for both abiotic reduction and microbial growth was need to optimize the sediment system for the most rapid mineralization rate. Results show that there are separate optimal abiotic/biostimulation aquifer sediment treatments for RDX/HMX and for TNT. Optimal sediment treatment for RDX and HMX (which have chemical similarities and similar degradation pathways) is mainly chemical reduction of sediment, which increased the RDX/HMX mineralization rate 100 to150 times (relative to untreated sediment), with additional carbon or trace nutrient addition, which increased the RDX/HMX mineralization rate an additional 3 to 4 times. In contrast, the optimal aquifer sediment treatment for TNT involves mainly biostimulation (glucose addition), which stimulates a TNT/glucose cometabolic degradation pathway (6.8 times more rapid than untreated sediment), degrading TNT to amino-intermediates that irreversibly sorb (i.e., end product is not CO2). The TNT mass migration risk is minimized by these transformation reactions, as the triaminotoluene and 2,4- and 2,6-diaminonitrotoluene products that irreversibly sorb are no longer mobile in the subsurface environment. These transformation rates are increased 13 times further by chemical reduction of sediment. Dithionite reduction alone is not an effective treatment for TNT (intermediates that irreversibly sorb are ...
Date: August 7, 2007
Creator: Szecsody, James E.; Comfort, Steve; Fredrickson, Herbert L.; Boparai, Hardiljeet K.; Devary, Brooks J.; Thompson, Karen T. et al.
Partner: UNT Libraries Government Documents Department

Technology Survey to Support Revision to the Remedial Investigation/Feasibility Study Work Plan for the 200­-SW­-2 Operable Unit at the U.S. Department of Energy’s Hanford Site

Description: A survey of technologies was conducted to provide information for a Data Quality Objectives process being conducted to support revision of the Remedial Investigation/Feasibility Study Work Plan for the 200-SW-2 Operable Unit. The technology survey considered remediation and characterization technologies. This effort was conducted to address, in part, comments on the previous version of the Remedial Investigation/Feasibility Study Work Plan for the 200-SW-2 Operable Unit as documented in 200­SW­1 and 200­SW­2 Collaborative Workshops―Agreement, Completion Matrix, and Supporting Documentation. By providing a thorough survey of remediation and characterization options, this report is intended to enable the subsequent data quality objectives and work plan revision processes to consider the full range of potential alternatives for planning of the Remedial Investigation/Feasibility Study activities.
Date: September 25, 2007
Creator: Truex, Michael J.; Johnson, Christian D. & Nimmons, Michael J.
Partner: UNT Libraries Government Documents Department

Baseline Natural Attenuation Processes Lines of Inquiry Supporting Monitored Natural Attenuation of Chlorinated Solvents

Description: The Department of Energy is sponsoring an initiative to facilitate efficient, effective and responsible use of Monitored Natural Attenuation and Enhanced Passive Remediation for chlorinated solvents. This Office of Environmental Management ''Alternative Project,'' focuses on providing scientific and policy support for MNA/EPR. A broadly representative working group of scientists supports the project along with partnerships with regulatory organizations such as the Interstate Technology Regulatory Council and the Environmental Protection Agency. The initial product of the technical working group was a summary report that articulated the conceptual approach and central scientific tenants of the project, and that identified a prioritized listing of technical targets for field research. This report documented the process in which scientific ground rules were developed, lines of inquiry were identified and then critically evaluated, promising applied research topics were highlighted in the various lines of inquiry, and these were discussed and prioritized. The summary report will serve as a resource to guide management and decision making throughout the period of the subject MNA/EPR Alternative Project. To support and more fully document the information presented in the summary report, we are publishing a series of supplemental documents that present the full texts from the technical analyses within the various lines of inquiry. The following report documenting our evaluation of the state of the science of baseline natural attenuation processes is one of those supplemental documents.
Date: May 18, 2004
Creator: Chapelle, F
Partner: UNT Libraries Government Documents Department

Final Technical Report for DOE Award DE-FG07-00ID13890

Description: The ITRC is a state-led national coalition dedicated to developing tools and strategies to overcome barriers and enable the deployment of beneficial new environmental technologies. ITRC works in partnership with federal agencies, industry, academia, and public and tribal stakeholders to develop these tools and strategies and means of disseminating the tools to state environmental regulators, and technology users
Date: February 28, 2006
Creator: Titus, Timothy R.
Partner: UNT Libraries Government Documents Department

Influence of Wetting and Mass Transfer Properties of Organic Chemical Mixtures in Vadose Zone Materials on Groundwater Contamination by Nonaqueous Phase Liquids

Description: Previous studies have found that organic acids, organic bases, and detergent-like chemicals change surface wettability. The wastewater and NAPL mixtures discharged at the Hanford site contain such chemicals, and their proportions likely change over time due to reaction-facilitated aging. The specific objectives of this work were to (1) determine the effect of organic chemical mixtures on surface wettability, (2) determine the effect of organic chemical mixtures on CCl4 volatilization rates from NAPL, and (3) accurately determine the migration, entrapment, and volatilization of organic chemical mixtures. Five tasks were proposed to achieve the project objectives. These are to (1) prepare representative batches of fresh and aged NAPL-wastewater mixtures, (2) to measure interfacial tension, contact angle, and capillary pressure-saturation profiles for the same mixtures, (3) to measure interphase mass transfer rates for the same mixtures using micromodels, (4) to measure multiphase flow and interphase mass transfer in large flow cell experiments, all using the same mixtures, and (5) to modify the multiphase flow simulator STOMP in order to account for updated P-S and interphase mass transfer relationships, and to simulate the impact of CCl4 in the vadose zone on groundwater contamination. Results and findings from these tasks and summarized in the attached final report.
Date: May 21, 2011
Creator: Werth, Charles J & Albert J Valocchi, Hongkyu Yoon
Partner: UNT Libraries Government Documents Department

Characterization of Sediments from the Soil Desiccation Pilot Test (SDPT) Site in the BC Cribs and Trenches Area

Description: This technical report documents the results of laboratory geochemical and hydrologic measurements of sediments collected from new borehole 299-E13-65 (C7047) and comparison of the results with those of nearby borehole 299-13E-62 (C5923) both drilled in the BC Cribs and Trenches Area. The total and water-leachable concentrations of key contaminants will be used to update contaminant-distribution conceptual models and to provide more data for improving baseline risk predictions and remedial alternative selections. Improved understanding of subsurface conditions and methods to remediate these principal contaminants can be also used to evaluate the application of specific technologies to other contaminants across the Hanford Site.
Date: September 25, 2009
Creator: Um, Wooyong; Truex, Michael J.; Valenta, Michelle M.; Iovin, Cristian; Kutnyakov, Igor V.; Chang, Hyun-shik et al.
Partner: UNT Libraries Government Documents Department