bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ground Water Remediation Using an Extraction, Treatment, and Recharge System
Authors: Thomsen Kurt O. , Chaudhry Majid A. , Dovantzis Kostas , Riesing Ronald R. 
Published: February 2007

AbstractGround water remediation of volatile organic compound (VOC) contamination at a site in Michigan was initiated as a result of a consent agreement between the Michigan Department of Natural Resources (MDNR) and the responsible party. Under the direction of the MDNR, the responsible party conducted a remedial investigation/feasibility study using federal guidelines to define the extent of contamination at the site and to select a response action for site remediation. The selected alternative included a combination of ground water extraction, treatment, and recharge, and soil flushing. The extraction system withdraws ground water from various depths in heavily contaminated areas. The ground water is treated using an air stripper. A spray distribution system spreads effluent from the stripper over a recharge basin constructed over the most contaminated areas. Additional contaminant removal is achieved by volatilization from the spray and percolation through the gravel bed. Recharge water moves downward through the contaminated soils, thus flushing residual soil contaminants. The initial operating data demonstrated that the system can effectively remove trichloroethylene (TCE) from ground water (approximately 95 percent overall removal efficiency). The annualized capital and operation and maintenance (O & M) costs of the remedial action were estimated for several operating periods (15, 20, and 30 years).
Economics of Sample Compositing as a Screening Tool in Ground Water Quality Monitoring
Authors: Rajagopal R. , Williams L.R. 
Published: February 2007

AbstractRecent advances in high throughput/automated compositing with robotics/field‐screening methods offer seldom‐tapped opportunities for achieving cost‐reduction in ground water quality monitoring programs. An economic framework is presented in this paper for the evaluation of sample compositing as a screening tool in ground water quality monitoring. When the likelihood of occurrence of a contaminant in a well is very small, the use of sample compositing instead of routine exhaustive sampling will lead to reduction in analytical efforts. Such reduction will be maximum when there are no contaminated wells in the network. An N‐fold reduction will result when none of the wells in a network of N wells are contaminated. When 25 percent or more wells in a network are contaminated, the use of sample compositing will require, at the most, an additional 50 percent analytical effort compared to exhaustive sampling. A quantitative measure of the cost‐effectiveness of sample compositing as a screening tool is shown to be dependent on two factors: a ratio (f1) of laboratory analytical cost to that of well installation and field sampling costs and a ratio (f2) of the expected number of contaminated wells to that of the total number of wells in the network. Several useful mathematical results of primary interest are derived and illustrated with case examples in the paper. Selected areas for further research are also outlined.
The Organization and Operation of the Savannah River Plant's Groundwater Monitoring Program
Authors: Olson C.M. , Heffner J.D. 
Published: February 2007

AbstractThe Groundwater Monitoring Program at the Savannah River Plant currently consists of more than 700 wells at more than 70 sites, and growth is projected. The organization and operation of the program has been designed to support an active drilling program, the acquisition of a large amount of repetitive data, the generation of numerous reports, associated QA/QC controls, and provisions for additional growth. The design is centered around two key features—modular components and computer usage.The modular component concept is an organizational tool that gives one group responsibility for a specific portion of the program. This responsibility includes the operation of its segment and the coordination of operations with the other groups in the program.Computers, the associated software programs, and a simple set of rules (the sampling guide) enables the program to accommodate large amounts of repetitive data in a timely, uniform manner. Feedback loops are included to ensure that new data are incorporated into future program decisions (new sample schedules and well locations). The highly automated system determines new sample schedules, collates/reviews incoming data, and generates various reports. Six reports are issued on a regular basis, from quarterly to annually, to ensure that the program is adequately documented.The program has been in successful operation for more than a year and has accommodated the expected growth.
A Tracer Test for Detecting Cross Contamination Along a Monitoring Well Column
Authors: Meiri David 
Published: February 2007

AbstractA tracer test was used to evaluate whether cross contamination exists along a monitoring well completed through a shallow ground water system in fractured clay and screened in a sand and gravel aquifer. The fractured clay is separated from the sand and gravel deposit by a layer of highly plastic unfractured clay. A natural vertical downward hydraulic gradient of approximately 0.5 exists between the shallow system and the sand and gravel aquifer. Ground water contamination was detected in an adjacent monitoring well screened in the fractured clay and in the monitoring well screened in the sand and gravel deposit. No ground water contamination was apparent in an intermediate well screened in the unfractured clay layer. A tracer of sodium bromide was injected into a shallow boring near the monitoring wells. The tracer was detected in the monitoring well in the sand and gravel aquifer after three to seven days. The bromide concentration continued to increase in this well with time while the concentration in the shallow boring declined. This trend of tracer concentration indicates the tracer has in fact migrated downward and possibly traveled along the well column.
Use of On‐Site High Performance Liquid Chromatography to Evaluate the Magnitude and Extent of Organic Contaminants in Aquifers
Authors: Goerlitz Donald F. , Franks Bernard J. 
Published: February 2007

AbstractScientists engaged in the appraisal of ground water contaminated by organic substances are faced with the problems of difficult sample collection and timely chemical analysis. High‐performance liquid chromatography was evaluated for on‐site determination of specific organic contaminants in ground water samples and was used at three study sites. Organic solutes were determined directly in water samples, with little or no preparation, and usually in less than an hour after collection. This information improved sampling efficiency and was useful in screening for subsequent laboratory analysis. On two occasions, on‐site analysis revealed that samples were undergoing rapid change, with major solutes being upgraded and alteration products being formed. In addition to sample stability, this technique proved valuable for monitoring other sampling factors such as compositional changes with respect to pumping, filtration, and cross contamination.
A Critique of the Hvorslev Method for Slug Test Analysis: The Fully Penetrating Well
Authors: Chirlin Gary R. 
Published: February 2007

AbstractThe Hvorslev (1951) method of slug test analysis addresses a variety of well and aquifer geometries, is easy to apply, and is widely used. Its underlying mathematical model assumes negligible compressive storage (aquifer water and matrix are incompressible, flow is quasi‐steady). The consequences of this assumption are explored here for the particular case of a well fully penetrating a confined, radially infinite, homogeneous, isotropic aquifer. The Cooper et al. (1967) model of this setting includes the effect of compressive storage and is otherwise identical to Hvorslev. Therefore, for this setting the performance of the Hvorslev method is gauged against that of the Cooper et al. model.The original Hvorslev model is recast into conventional governing equations to facilitate the comparison with Cooper et al. The Hvorslev estimate of hydraulic conductivity for this setting is accurate only to within an order of magnitude, assuming no knowledge of the aquifer storage coefficient. Accuracy of the Hvorslev estimate depends on the normalized aquifer storage coefficient α, on the matching procedure used to fit the Hvorslev model, and on the analyst's choice for the Hvorslev effective radius re.The Hvorslev model provides no physical basis for selecting re. Some insight is gained by viewing the constant head condition at radius re as an “infinite storage” at re. Flow from this discrete “storage” approximates the distributed storage of a compressible aquifer. By reference to Cooper et al. one can select a value of re, which leads to a correct Hvorslev estimate of hydraulic conductivity, given prior knowledge of the aquifer storage coefficient.For an example aquifer, the Hvorslev and Cooper et al. models yield substantially different distributions of head within the aquifer.Quantitative comparisons here are restricted to a single setting. Hvorslev (1951) also addresses a number of other settings (partial penetration, no lower aquiclude). A companion paper, in preparation, will examine the significance of the incompressibility assumption for these other, more widely applied settings.
Planning Ground Water Monitoring Field Projects
Authors: Lister Kenneth H. 
Published: February 2007

AbstractProject organization problems are not uncommon in ground water monitoring projects, particularly those which occur at sites remote from the office. Successful project management depends on coordination of the personnel, supplies, and equipment necessary to carry out each phase of the project. Procedures for planning and organizing field projects involving well installation, ground water sampling, and aquifer testing are outlined. Methods are suggested that will aid the Project Manager in planning and scheduling field work to make efficient use of personnel and material resources. Cautions are given regarding common pitfalls of projects involving operations at remote sites, and means of avoidance are enumerated. A checklist of commonly used field equipment and supplies is provided.
Application of Temperature and Electrical‐Conductivity Logging in Ground Water Monitoring
Authors: Michalski Andrew 
Published: February 2007

AbstractDown‐hole temperature and electrical‐conductivity probes are attractive logging devices for use in monitoring wells, because they are readily available, relatively inexpensive, and allow for rapid measurements. Benefits of such logging are illustrated by examples from several small sites in complex hydrogeologic settings. Interpretation of the logs provided information on the effectiveness of well purging, aquifer heterogeneities and the rates of ground water movement, leaks and cross‐flows within wells, and locations of transmissive fractures in bedrock wells. Thus the logs offered an inexpensive means of acquiring valuable field information to supplement the geologic, potentiometric and chemical data collected during construction or subsequent investigation of the wells.
Modeling the Potential Effect of Additives on Enhancing the Solubility of Aromatic Solutes Contained in Gasoline
Authors: Mihelcic James R. 
Published: February 2007

AbstractThe potential effect of two common gasoline additives, ethanol and methyl tertiary‐butyl ether (MTBE), on enhancing the solubility of the aromatic solutes benzene, toluene, ethylbenzene, and o‐, m‐, and p‐xylene, was examined using a computer model, ARSOL. Aqueous solute systems containing cosolvents ethanol and MTBE at 0, 0.1, 1, and 4.3 percent were modeled for both ethanol and MTBE systems. Five‐ and 10‐percent ethanol systems were also modeled. Little solubility enhancement was predicted by modeling at cosolvent levels less than 1 percent. At cosolvent levels greater than 1 percent, predicted solute solubility increased curvilinearly with an increase in percent cosolvent; a 10 percent cosolvent system increased aromatic hydrocarbon solubility by approximately 100 percent. According to the model predictions, MTBE enhanced solute solubility more than ethanol, with enhancement by MTBE being approximately 10 percent greater than enhancement by ethanol at 4.3 percent cosolvent. Other concerns regarding gasoline additives are the observed reduction in partitioning of solutes to soils and sediments and the contamination of water supplies due to the high water solubility of the additives.
Organic Contamination of Ground Water at Gas Works Park, Seattle, Washington
Authors: Turney G.L. , Goerlitz D.F. 
Published: February 2007

AbstractGas Works Park, in Seattle, Washington, is located on the site of a coal and oil gasification plant that ceased operation in 1956. During operation, many types of wastes, including coal, tar, and oil, accumulated on‐site. The park soil is currently (1986) contaminated with compounds such as polynuclear aromatic hydrocarbons, volatile organic compounds, trace metals, and cyanide. Analyses of water samples from a network of observation wells in the park indicate that these compounds are also present in the ground water.Polynuclear aromatic hydrocarbons and volatile organic compounds were identified in ground water samples in concentrations as large as 200 mg/L. Concentrations of organic compounds were largest where ground water was in contact with a non‐aqueous phase liquid in the soil. Where no non‐aqueous phase liquid was present, concentrations were much smaller, even if the ground water was in contact with contaminated soils. This condition is attributed to weathering processes in which soluble, low‐molecular‐weight organic compounds are preferentially dissolved from the non‐aqueous phase liquid into the ground water. Where no non‐aqueous phase liquid is present, only stained soils containing relatively insoluble, high‐molecular‐weight compounds remain. Concentrations of organic contaminants in the soils may still remain large.
Magnetic Surveying for Buried Metallic Objects
Authors: Barrows Larry , Rocchio Judith E. 
Published: February 2007

AbstractField tests were conducted to determine representative total‐intensity magnetic anomalies due to the presence of underground storage tanks and 55‐gallon steel drums. Three different drums were suspended from a non‐magnetic tripod and the underlying field surveyed with each drum in an upright and a flipped plus rotated orientation. At drum‐to‐sensor separations of 11 feet, the anomalies had peak values of around 50 gammas and half‐widths about equal to the drum‐to‐sensor separation. Remanent and induced magnetizations were comparable; crushing one of the drums significantly reduced both. A profile over a single underground storage tank had a 1000‐gamma anomaly, which was similar to the modeled anomaly due to an infinitely long cylinder horizontally magnetized perpendicular to its axis. A profile over two adjacent tanks had a smooth 350‐gamma single‐peak anomaly even though models of two tanks produced dual‐peaked anomalies. Demagnetization could explain why crushing a drum reduced its induced magnetization and why two adjacent tanks produced a single‐peak anomaly.A 40‐acre abandoned landfill was surveyed on a 50‐ by 100‐foot rectangular grid and along several detailed profiles. The observed field had broad positive and negative anomalies that were similar to modeled anomalies due to thickness variations in a layer of uniformly magnetized material. It was not comparable to the anomalies due to induced magnetization in multiple, randomly located, randomly sized, independent spheres, suggesting that demagnetization may have limited the effective susceptibility of the landfill material. A different 6‐acre site survey conducted on a 10‐ by 10‐foot grid was analyzed to determine the maximum station spacing and line separation that could have been used. Essentially, all of the anomalies at this site would have been resolved by a survey conducted on a 20‐ by 20‐foot grid and the larger anomalies would have been detected by a 50‐ by 50‐foot grid.
Complementary Investigative Techniques for Site Assessment with Low‐Level Contaminants
Authors: Byrnes Mark E. , Nelson R. Wayne , La Poe Robert G. , Lundquist Dennis E. , McNeill William 
Published: February 2007

AbstractA remedial investigation (RI) was performed in an area downgradient from an abandoned missile silo at Vandenberg Air Force Base, California, as part of the United States Air Force Installation Restoration Program (IRP). A number of complementary investigative techniques were used to assure a reliable assessment of site contamination. These included the review of aerial photographs, the use of an organic vapor analyzer (OVA) and carbon adsorption/mass spectrometer (MS) method to conduct a soil‐gas survey; magnetic and electromagnetic geophysical surveys; bedrock permeability testing; and the chemical analysis of soil, sediment, surface water, and ground water samples. The results from this investigation revealed the presence of an undocumented landfill and a small trichloroethylene plume in ground water at concentrations ranging from 6.7 ppb to 31 ppb. The investigation also identified local ground water flow direction, provided strong evidence of the location of potential sources of contamination, and defined the downgradient extent of ground water contamination. Because the identified contaminants have not as yet reached the environmentally sensitive wetland at the base of the slope below this facility, there is still time to propose remedial alternatives that would serve to protect this environmentally sensitive area.
Factors Affecting Efficient Aquifer Restoration at In Situ Uranium Mine Sites
Authors: Osiensky James L. , Williams Roy E. 
Published: February 2007

AbstractIn situ mining of uranium typically requires the injection of a reactive leaching solution (lixiviant) such as sodium carbonate/bicarbonate, ammonium carbonate/bicarbonate, or sulfuric acid, and an oxidant such as hydrogen peroxide or oxygen into an ore‐bearing, confined aquifer. It also requires the environmental restoration of the source aquifer. The stratigraphy of sandstone uranium deposits typically consists of interbedded layers of poorly consolidated sands and clays and gravels deposited in fluvial or coastal environments. The parameters that influence the migration of lixiviant during mining and restoration in these environments include induced hydraulic gradients, hydrodynamic dispersion, heterogeneity, anisotropy, physicochemical reactions, leakage into and/or through confining layers, and convergence of flow lines due to partial well penetration.The effectiveness of the various methods of aquifer restoration is sit ‐specific and is dependent upon the site hydrogeology and hydrogeochemistry, and the chemistry of the lixiviant. Each method of aquifer restoration has advantages and disadvantages. Selection of the most effective and economically feasible method requires detailed knowledge of the site‐specific hydrogeologic conditions.
A Practical Approach to the Design, Operation, and Monitoring of In Situ Soil‐Venting Systems
Authors: Johnson P.C. , Stanley C.C. , Kemblowski M.W. , Byers D.L. , Colthart J.D. 
Published: February 2007

AbstractWhen operated properly, in situ soil venting or vapor extraction can be one of the most cost‐effective remediation processes for soils contaminated with gasoline, solvents, or other relatively, volatile compounds. The components of soil‐venting systems are typically off‐the‐shelf items, and the installation of wells and trenches can be done by reputable environmental firms. However, the design, operation, and monitoring of soil‐venting systems are not trivial. In fact, choosing whether or not venting should be applied at a given site is a difficult decision in itself. If one decides to utilize venting, design criteria involving the number of wells, well spacing, well location, well construction, and vapor treatment systems must be addressed. A series of questions must be addressed to decide if venting is appropriate at a given site and to design cost‐effective in situ soil‐venting systems. This series of steps and questions forms a “decision tree” process. The development of this approach is an attempt to identify the limitations of in situ soil venting, and subjects or behavior that are currently difficult to quantify and for which future study is needed.
Aqueous Surfactant Washing of Residual Oil Contamination from Sandy Soil
Authors: Ang Carolina C. , Abdul Abdul S. 
Published: February 2007

AbstractA laboratory study was conducted to determine the efficiency of different aqueous concentrations of an alcohol ethoxylate surfactant in washing residual levels of an oil [automatic transmission fluid (ATF)] from sandy soil. Five glass columns packed with the soil were prepared in a manner that simulated conditions leading to residual saturation in an actual oil leak. Each of four columns was washed continuously with 28 pore volumes of solution by pumping either 0.0 percent (water), 0.5 percent, 1.0 percent, or 2.0 percent aqueous surfactant solutions through the columns. The fifth column was washed intermittently with 28 pore volumes of a 1.0 percent surfactant solution. Water washed only 25.5 percent of the ATF from the column soil, while the 0.5 percent, 1 percent, and 2 percent surfactant solutions washed 55 percent, 60 percent, and 72.8 percent of the ATF, respectively. The distribution of the ATF remaining in the column after washing showed that the ATF removed by water was mainly from the outlet side of the column, while the ATF removed by the 2.0 percent surfactant solution was mainly from the inlet side of the column. This observation indicated that different mechanisms were involved; namely, the displacement of oil through the soil‐pore space, the dispersion of oil due to reduced surface tension, and the solubilization of oil by surfactant micelles. In the case of water, the displacement of oil was the main washing mechanism, while all three mechanisms were operative during surfactant washing. ATF dispersion and solubilization were improved at higher surfactant concentrations. The column that was washed intermittently to pulse ATF from dead end pores did not show a significant improvement over the column that was continuously washed with the same 1.0 percent surfactant solution. The results show promising potential for application in the field and will be further investigated in a two‐dimensional model aquifer.