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Book Energy Research Abstracts

Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Demonstration and Validation of the Use of Passive Samplers for Monitoring Soil Vapor Intrusion to Indoor Air

Download or read book Demonstration and Validation of the Use of Passive Samplers for Monitoring Soil Vapor Intrusion to Indoor Air written by Todd Arthur McAlary and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis documents a demonstration/validation of passive diffusive samplers for assessing soil vapor, indoor air and outdoor air concentrations of volatile organic compounds (VOCs) at sites with potential human health risks attributable to subsurface vapor intrusion to indoor air. The study was funded by the United States (U.S.) Department of Defense (DoD) and the U.S. Department of the Navy (DoN). The passive samplers tested included: SKC Ultra and Ultra II, Radiello®, Waterloo Membrane Sampler (WMS), Automated Thermal Desorption (ATD) tubes, and 3M OVM 3500. The program included laboratory testing under controlled conditions for 10 VOCs (including chlorinated ethenes, ethanes, and methanes, as well as aromatic and aliphatic hydrocarbons), spanning a range of properties and including some compounds expected to pose challenges (naphthalene, methyl ethyl ketone). Laboratory tests were performed under conditions of different temperature (17 to 30 oC), relative humidity (30 to 90 % RH), face velocity (0.014 to 0.41 m/s), concentration (1 to 100 parts per billion by volume [ppbv]) and sample duration (1 to 7 days). These conditions were selected to challenge the samplers across a range of conditions likely to be encountered in indoor and outdoor air field sampling programs. A second set of laboratory tests were also conducted at 1, 10 and 100 parts per million by volume (ppmv) to evaluate concentrations of interest for soil vapor monitoring using the same 10 VOCs and constant conditions (80% RH, 30 min exposure, 22 oC). Inter-laboratory testing was performed to assess the variability attributable to the differences between several laboratories used in this study. The program also included field testing of indoor air, outdoor air, sub-slab vapor and deeper soil vapor at several DoD facilities. Indoor and outdoor air samples were collected over durations of 3 to 7 days, and Summa canister samples were collected over the same durations as the passive samples for comparison. Subslab and soil vapor samples were collected with durations ranging from 10 min to 12 days, at depths of about 15 cm (immediately below floor slabs), 1.2 m and 3.7 m. Passive samplers were employed with uptake rates ranging from about 0.05 to almost 100 mL/min and analysis by both thermal desorption and solvent extraction. Mathematical modeling was performed to provide theoretical insight into the potential behavior of passive samplers in the subsurface, and to help select those with uptake rates that would minimize the risk of a negative bias from the starvation effect (which occurs when a passive sampler with a high uptake rate removes VOC vapors from the surroundings faster than they are replenished, resulting in biased concentrations). A flow-through cell apparatus was tested as an option for sampling existing sub-surface probes that are too small to accommodate a passive sampler or sampling a slip-stream of a high-velocity gas (e.g., vent-pipes of mitigation systems). The results of this demonstration show that all of the passive samplers provided data that met the performance criteria for accuracy and precision (relative percent difference less than 45 % for indoor air or 50% for soil vapor compared to conventional active samples and a coefficient of variation less than 30%) under some or most conditions. Exceptions were generally attributable to one or more of five possible causes: poor retention of analytes by the sorbent in the sampler; poor recovery of the analytes from the sorbent; starvation effects, uncertainty in the uptake rate for the specific combination of sampler/compound/conditions, or blank contamination. High (or positive) biases were less common than low biases, and attributed either to blank contamination, or to uncertainty in the uptake rates. Most of the passive samplers provided highly reproducible results throughout the demonstrations. This is encouraging because the accuracy can be established using occasional inter-method verification samples (e.g., conventional samples collected beside the passive samples for the same duration), and the field-calibrated uptake rates will be appropriate for other passive samples collected under similar conditions. Furthermore, this research demonstrated for the first time that passive samplers can be used to quantify soil vapor concentrations with accuracy and precision comparable to conventional methods. Passive samplers are generally easier to use than conventional methods (Summa canisters and active ATD tubes) and minimal training is required for most applications. A modest increase in effort is needed to select the appropriate sampler, sorbent and sample duration for the site-specific chemicals of concern and desired reporting limits compared to Summa canisters and EPA Method TO-15. As the number of samples in a given program increases, the initial cost of sampling design becomes a smaller fraction of the overall total cost, and the passive samplers gain a significant cost advantage because of the simplicity of the sampling protocols and reduced shipping charges.

Book Soil Vapor Extraction Using Radio Frequency Heating

Download or read book Soil Vapor Extraction Using Radio Frequency Heating written by Donald F. Lowe and published by CRC Press. This book was released on 2023-05-31 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most widely used techniques for treating soils contaminated with volatile organic compounds, soil vapor extraction (SVE) can also be applied to semi-volatile organic compounds (SVOCs) if the soil is heated, by applying electromagnetic energy in the radio frequency (FR) range, to increase the vapor pressure of the contaminants. Although RF-SVE systems used in previous field demonstrations have had varying degrees of success, questions remain concerning its viability and cost-effectiveness. Soil Vapor Extraction Using Radio Frequency Heating: Resource Manual and Technology Demonstration covers detailed scientific and engineering information that answers these questions. The book includes the necessary databases, equations, and example calculations for RF heating. The theoretical and practical information included will facilitate future testing of RF-SVE treatment of soils. Additionally, the book provides information for a full-scale engineering design of potential RF-SVE applications. The authors use this information to examine predicted performance, magnitude of costs, and modifications to the design that may decrease cost. Soil Vapor Extraction Using Radio Frequency Heating: Resource Manual and Technology Demonstration gives an economic analysis of this innovative technology and considers other possible applications for it. Features

Book SOIL VAPOR EXTRACTION SYSTEM DESIGN

Download or read book SOIL VAPOR EXTRACTION SYSTEM DESIGN written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil vapor extraction (SVE) systems are typically designed based on the results of a vadose zone pumping test (transient or steady state) using a pressure criteria to establish the zone of influence (ZOI). A common problem associated with pressure based SVE design is overestimating the ZOI of the extraction well. The vacuum criteria commonly used to establish the boundary of the ZOI results in large areas with very low pore velocities and thus long cleanup times. As a result, design strategies based upon critical pore gas velocity (CPGV) have increased in popularity. The CPGV is used in an effort to loosely incorporate the effects of mass transfer limitations into the design of SVE systems. Critical pore gas velocity designs use a minimum pore gas velocity rather than minimum vacuum to identify the extent of the treatment zone of an SVE system. The CPGV is typically much larger than the pore gas velocity at the perimeter of vacuum based (ZOI) designs resulting in shorter cleanup times. In this paper, we report the results of testing performed at the Savannah River Site (SRS) to determine the influence of a vapor extraction well based upon both a pressure and pore gas velocity design criteria. Results from this testing show that a SVE system designed based upon a CPGV is more robust and will have shorter cleanup times due to increased flow throughout the treatment zone. Pressure based SVE design may be appropriate in applications where soil gas containment is the primary objective; however, in cases where the capture and removal of contaminated soil gas is the primary objective, CPGV is a better design criteria.

Book Field Tests of Passive Soil Vapor Extraction Systems at the Hanford Site Washington

Download or read book Field Tests of Passive Soil Vapor Extraction Systems at the Hanford Site Washington written by Virginia J. Rohay and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book SITE Program Demonstration Test

Download or read book SITE Program Demonstration Test written by Peter A. Michaels and published by . This book was released on 1989 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Government Reports Announcements Index

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1995 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Subsurface Volatilization and Ventilation System SVVS

Download or read book Subsurface Volatilization and Ventilation System SVVS written by and published by . This book was released on 1995 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Stakeholder Acceptance Analysis

Download or read book Stakeholder Acceptance Analysis written by Todd S. Peterson and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A Model for Economically Based Conceptual Design of Soil Vapor Extraction Systems

Download or read book A Model for Economically Based Conceptual Design of Soil Vapor Extraction Systems written by and published by . This book was released on 1990 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil vapor extraction, also known as in situ soil venting, is rapidly becoming a widespread technique for the remediation of sites containing soils contaminated with volatile compounds. In this process, the soil is decontaminated in place by inducing air flow through the contaminated soil zones. Air, removed from the soil through extraction vents using a vacuum blower, may be resupplied by infiltration from the surface or through forced or passive inlet vents. This air flow sweeps out the soil gas, disrupting the equilibrium existing between contaminants which are (1) sorbed onto the soil particles, (2) dissolved in soil pore water, (3) held in a separate contaminant phase, and (4) existing in the vapor phase. This causes vaporization of the contaminants and removal in the extracted gas stream. Emissions control devices are often necessary for treatment of the gas stream prior to discharge. By preventing the hazards caused by subsurface vapor movement and by removing the contaminants before they reach groundwater, soil vapor extraction is extremely useful in decontaminating unsaturated zone soils. The technology may also be used in conjunction with pump-and-treat groundwater remediation techniques for complete cleanup of soil and groundwater in cases where the contaminants have reached the water table. 22 refs., 9 figs.

Book A Transient Method of Soil Vapor Extraction Testing Involving Vertical Air Leakage

Download or read book A Transient Method of Soil Vapor Extraction Testing Involving Vertical Air Leakage written by Gerry Dudley Beckett and published by . This book was released on 1993 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book ENHANCED ATTENUATION TECHNOLOGIES

Download or read book ENHANCED ATTENUATION TECHNOLOGIES written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Passive soil vapor extraction (PSVE) is an enhanced attenuation (EA) approach that removes volatile contaminants from soil. The extraction is driven by natural pressure gradients between the subsurface and atmosphere (Barometric Pumping), or by renewable sources of energy such as wind or solar power (Assisted PSVE). The technology is applicable for remediating sites with low levels of contamination and for transitioning sites from active source technologies such as active soil vapor extraction (ASVE) to natural attenuation. PSVE systems are simple to design and operate and are more cost effective than active systems in many scenarios. Thus, PSVE is often appropriate as an interim-remedial or polishing strategy. Over the past decade, PSVE has been demonstrated in the U.S. and in Europe. These demonstrations provide practical information to assist in selecting, designing and implementing the technology. These demonstrations indicate that the technology can be effective in achieving remedial objectives in a timely fashion. The keys to success include: (1) Application at sites where the residual source quantities, and associated fluxes to groundwater, are relatively low; (2) Selection of the appropriate passive energy source - barometric pumping in cases with a deep vadose zone and barrier (e.g., clay) layers that separate the subsurface from the atmosphere and renewable energy assisted PSVE in other settings and where higher flow rates are required; and (3) Provision of sufficient access to the contaminated vadose zones through the spacing and number of extraction wells. This PSVE technology report provides a summary of the relevant technical background, real-world case study performance, key design and cost considerations, and a scenario-based cost evaluation. The key design and cost considerations are organized into a flowchart that dovetails with the Enhanced Attenuation: Chlorinated Organics Guidance of the Interstate Technology and Regulatory Council (ITRC). The PSVE flowchart provides a structured process to determine if the technology is, or is not, reasonable and defensible for a particular site. The central basis for that decision is the expected performance of PSVE under the site specific conditions. Will PSVE have sufficient mass removal rates to reduce the release, or flux, of contamination into the underlying groundwater so that the site can meet it overall remedial objectives? The summary technical information, case study experiences, and structured decision process provided in this 'user guide' should assist environmental decision-makers, regulators, and engineers in selecting and successfully implementing PSVE at appropriate sites.

Book Terra Vac in Situ Vacuum Extraction System

Download or read book Terra Vac in Situ Vacuum Extraction System written by and published by . This book was released on 1989 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: