Description of REU Projects for Summer 2000

TITLE: Iron Oxidation Kinetics in a Wetland Receiving Alkaline Mine Drainage

Abstract: Mine discharge waters at the Tar Creek Superfund Site in Oklahoma contain substantial alkalinity and have circumneutral pH but elevated concentrations of Fe, Zn, Cd and Pb. An understanding of iron oxidation kinetics is necessary to design effective remediation strategies (most likely treatment wetlands) for these waters. In summer 2000, we measured biotic and abiotic rates of iron oxidation in microcosms at a volunteer wetland receiving polluted mine waters from two boreholes. Water was pumped from each of borehole and from the middle of the wetland directly into control microcosms (biotic + abiotic) and through both 5 micrometer and 0.2 micrometer filters into separate experimental microcosms (abiotic). All microcosms (0.425 m3) were sampled at predetermined time intervals. Field parameters (pH, temperature, and alkalinity) and total and reduced iron were determined. Changes in reduced and total iron concentrations indicated that there was no significant difference in rates of iron oxidation between the control (abiotic + biotic) and experimental reactions (abiotic). The control reaction resulted in decreases in ferrous iron at the rate of -1.4567 mg Fe+2·L-1·hr-1 whereas the experimental reaction had a rate of

-1.2250 mg Fe+2·L-1·hr-1. Bacterial analyses indicated the presence of iron-related bacteria, but results indicated that they are not significantly active in this system. Abiotic oxidation from exposure to air was the dominant form of iron oxidation in these circumneutral waters. Adequate aeration of the water will remove iron from solution. However, settling of the iron particulates may require substantial surface area in any proposed treatment scenario.

Publications/Presentations: Society of Wetland Scientists South Central Conference, October 2000, Little Rock Arkansas, Presentation, won first place in student presentation competition

Going to SWS National conference in May 2001, Chicago

Going to American Society of Surface Mining and Reclamation Conference (ASSMR) also a proceedings so a publication out of that June 2001 in Albuquerque, New Mexico. Top

TITLE: Ecological Analysis of a Volunteer Wetland Receiving Mine Drainage

Abstract: We studied the effects of heavy-metal polluted mine waters on the ecology of a volunteer cattail marsh at the Tar Creek Superfund site in northeast Oklahoma. Discharge of polluted underground mine waters over the last 20 years has led to the development of an extensive wetland ecosystem. Study sites included both the affected marsh within the flow of the mine seepage (East Marsh) and a background site fed by stormwater drainage (West Marsh). In both marshes, vegetation sampling transects were established and monitored for species richness. In the East Marsh, above and below ground biomass were sampled in five 0.5m2 quadrants. One quadrant was sampled in the West Marsh. Representative subsamples of biomass were dry ashed and roots, stems, leaves and flowers were analyzed for iron and zinc concentrations. In addition, macro- invertebrate community surveys were performed using a Surber sampler at three flowing water locations, artificial substrates at six locations, and by seining at one location. Fish community structure was analyzed by seining. Biomass determinations demonstrated that West Marsh had the highest total biomass and that the below ground biomass was consistently higher than the above ground biomass. Culm densities in the West Marsh were found to be lower than East Marsh with the largest number of culms per a square meter being 44 near the mine drainage seep. Cumulative stem lengths were to be directly related to stem densities. Percent coverage, in the marshes, was 75-95% throughout the transects and 11 different species of vegetation were identified. However, both marshes were dominated by the Typha spp. Dry ashing showed the highest amount of inorganic matter in the roots and the lowest amount in the above ground foliage. Metal analysis demonstrated that metals were concentrated in the roots, but that they did accumulate in the stems, leaves, and in the flowers. Iron concentrations were highest. Twelve taxa of macro invertebrates and two taxa of fish were identified. Gambusia spp. were the dominant fish taxa. West Marsh demonstrated signs of metal pollution. However, the wetland appears healthy although the vegetation is accumulating substantial amounts of metals.

Publications/Presentations: Society of Wetland Scientists South Central Conference, October 2000, Little Rock Arkansas, Presentation. Top

TITLE: Development of a New Method for Measurement of Henry’s Law Constants

Abstract: In this project, a new method of measuring Henry’s Law Constants was developed and tested. The method is optimized for low-volatility compounds, and makes use of a specially-designed countercurrent-flow air stripping tower. Henry’s Law Constant values are determined based on the equations of countercurrent mass transfer. The countercurrent packed tower was constructed during this first half of the project period, and then it was used to measure the Henry’s Law Constants of isopropanol and MTBE. Experimentally-determined results for these compounds were found to agree well with reported values.

Publications/Presentations: J. Caires, M. Suzuki, S. Velmurugan, T. Kibbey "Measurement of Henry’s Law Constants of Low Volatility Compounds Using a Countercurrent Air Stripping Method," in preparation for Journal of Environmental Engineering. Top

TITLE: Analysis of the Number of Gauges Required to Calibrate the Illinois River Basin

Abstract: Gage density remains an important question when considering WSR-88D radar calibration to a rain gage network. This study attempts to address this issue, as well as possible correction factors, storm size, and time progression analysis. The gage density was determined by considering the allowable margin of error, the total mean depth of each storm, and the standard error of the mean. Four different correction factors were analyzed, including the mean field bias and probability density function techniques. The total mean values were compared to that of the rain gage measurements after correction factor application. Average difference was also considered. Storm events were categorized depending on their total mean depth in mm, and time progression was considered through 6-hourly totals.

The results showed that the number of gages necessary to calibrate depends on the storm size and the accuracy desired. They further consider the smallest storms (with a mean total depth less than 6mm) unnecessary in these calculations due to their minimal effect on flooding and runoff. Ten gages are adequate to calibrate the Illinois River Basin with 60% confidence and an allowable margin of error of 20% of the mean. The probability density function correction factor was found to be the best at adjusting the mean to that of the mesonet. The storm size analysis showed a greater underestimation of radar for smaller storm events. The time progression analysis pinpointed the greatest radar error in the first two and last 6- hour periods, emphasizing the importance of taking into account spatial and time distribution. Top

TITLE: Transformation of Trichloroethylene by Iron Metal

Abstract: The common ground water pollutant trichloroethylene (TCE) is rapidly transformed by reactive substances commonly used in ground-water remediation applications, such as zero-valent metals. The suitability of such substances for remediation depends not only on the rates but also the products of transformation, with cis 1,2-dichloroethylene and vinyl chloride among the undesired products and acetylene among the desired products. The overall goal of this project is to determine the conditions under which the optimum product distribution is observed in TCE transformation by iron metal. Research activities during Summer 2000 focused on development of analytical methods for quantifying TCE and its potential reaction products, and preliminary experiments to measure rate constants for TCE decay and product formation in the presence of iron metal samples with different physical and chemical properties. Top

TITLE: Equilibrium and Kinetic Sorption Properties of Phenanthrene on Organic Aquifer Materials

Abstract: The organic nature of an aquifer medium may significantly influence the transportation of a dissolved organic hydrophobic contaminant throughout that medium. Contaminated groundwater analysis and remediation require an understanding of the sorption processes that occur between the contaminant and the contents of its medium. The authors listed above performed equilibrium and kinetic studies on an assortment of soils containing variable amounts of organic contents. Phenanthrene was used to simulate organic contamination. Previous studies have shown that organic carbon normalized sorption coefficients, or Koc values, tend to increase as amounts of particulate organic matter increase within a sample (1, 2, 3), and that when Koc values are concentration dependent, sorption is nonlinear over time (3). Observing the fraction of organic content (foc) within a soil has also revealed that variability exists in the organic content itself (3). This study has also demonstrated those results.

Publications/Presentations: Applied for presentation at the University of Oklahoma's Undergraduate Research Day Conference, April 7, 2001. Top

TITLE: Natural Attenuation of Heavy Metals in a Volunteer Wetland in Northeastern Oklahoma

Abstract: Worked was conducted at a Superfund site in the northeastern part of OK. The groundwater contaminated from past mining activity flowed out onto a pasture, inundating the entire area. Over the years a wetland formed. The overall purpose (with the assistance from other REU students) was to determine the function of the wetland. In particular, the purpose of this study was to determine if the organic matter formed by the volunteer wetland retained some of the metals from the water, therefore, decreasing the concentrations of the metals that flow from the wetland. Core samples of the sediment were collected from different location throughout the marshland and brought back to the laboratory. The samples were tested for levels of iron and zinc. Tests are on-going for cadmium and lead, as well as analyses of the available metal concentrations (for Fe, Zn, Cd, and Pb). From the data collected and analyzed so far, it appears that the substrate of the volunteer wetland is retaining some of the metals. Top

TITLE: Quantification of Partitioning Coefficients between BTEX Compounds and Norman Landfill Leachate using Soild Phase Microextraction

Abstract: Large leachate plumes have developed below the Norman Landfill as a result of a non-existent leachate collection system. As the plume leaches into the ground it can transport BTEX compounds. In order to understand the interactions occurring between the dissolved organic matter present in the leachate and the BTEX compounds, partitioning coefficients for the BTEX compounds between the dissolved organic matter and the aqueous phase have to be quantified. Solid phase microextraction (SPME) is a useful technique for measuring the amount of free BTEX compounds in aqueous solutions. A method for quantifying these coefficients is described, as well as many factors that must be considered when using the SPME technique. Special interest is given to the effects of saturated salt conditions on the sensitivity of the SPME technique. Top

TITLE: Formulation of Mix Design to Incorporate Hydrocarbon Affected Soil in Asphalt Stabilized Soil

Abstract: There have been many processes developed that result in the remediation of heavy-hydrocarbon and metal affected soil. Some of these processes include biodegradation, extraction, and thermal absorption. None of these processes, however, incorporates the material in a useful end product. A proven alternative to these methods is to stabilize the soil with asphalt emulsion and use it in the fabrication of Asphalt Stabilized Base (ASB). For the material to pass industry standards and engineering requirements, a mix design must be prepared to sufficiently incorporate all ingredients. The purpose of this study was to develop a mix design that would use as much contaminated soil in the process as possible. The soil used was from the Kerr-McGee Cleveland site in Oklahoma.

Publications/Presentations: "Formulation of Mix Design for Asphaltic Incorporation of Hydrocarbon Contaminated Soil" (R. Tarefder, M. Ruckgaber, M. Zaman, and D. Patton). Submitted for possible publication in the ASCE Journal of Materials in Civil Engineering (January 2001).

"Asphalt Encapsulation of Contaminated Soils and Aggregates" (R.A. Tarefder, M.E. Ruckgaber, M. Zaman, and D. Patton). Presented at the 7th International Petroleum Environmental Conference, held at Albuquerque, New Mexico, November 7-10, 2000. Top

TITLE: Determining the Hydraulic Residence Time of the Mayer’s Ranch Wetland, Ottawa County, Oklahoma, by Use of a Tracer Test and Step-Injection Modeling Techniques

Abstract: A tracer test was conducted and then modeled to determine the hydraulic residence time of the water moving through the wetland located at Mayer’s Ranch, Ottawa County, OK. The wetland began in 1979, when acid mine drainage seeped through two existing boreholes, and saturated the ground. Potassium Bromide was dissolved in water, and injected into the wetland at the borehole seepage point. Samples were collected at three sites downstream of the injection point. Both grab samples and autosamplers were used. Samples were analyzed in the laboratory for Bromide concentration. This data was then used to calibrate several models. Equations for step injection (for 5 minutes) were used to create single- and double-peak curves. At site 1, a close fit was found with a velocity of 0.35m/min and a dispersion coefficient of 0.2 m2/min. At site 2, an incomplete data set made it difficult to calibrate, but the model used had a velocity of 0.01 m/min and a dispersion coefficient of 0.5 m2/min. At site 3, data was difficult to interpret, and two models were created – a single-peak model and a double-peak model. The single-peak model had a velocity of 0.001 m/min and a dispersion coefficient of 3 m2/min. The double-peak model had a velocity of 0.001 m/min, a dispersion coefficient for the first peak of 13 m2/min, and a dispersion coefficient for the second peak of 2.5 m2/min. Within 10 meters of the seepage point, the average hydraulic residence time was determined to be 25 minutes. Based on the models for sites 2 and 3, the average hydraulic residence time for the rest of the wetland was determined to be between 3.8 and 131.9 days. In future research, more data collection is necessary. With only one set of data the models were calibrated, but it was not possible to validate the models. Also, more time invested into future research could create increasingly complex models, which could better model how the water moves through the wetland.

TITLE: Water Quality Survey of a Volunteer Wetland in Northeastern Oklahoma

Abstract: The Tar Creek Superfund site is an abandoned lead and zinc mining area in the Tri-State mining district consisting of Oklahoma, Kansas, and Missouri. Mayer Ranch, our study site, is located within the Tar Creek area in Ottawa County in northeastern Oklahoma. The site receives substantial amounts of mine discharge from two boreholes located at the site. The discharges began in 1979 and over the last 20 years a volunteer wetland has formed. The mine water contains substantial alkalinity and has circumneutral pH but elevated concentrations of Fe, Zn, Cd, Pb, and SO4. An understanding of the water quality at the site is necessary to design effective remediation strategies (most likely treatment wetlands) for these waters. In summer 2000, we measured several water quality parameters at eight locations, during predetermined time intervals, within the marsh to determine the water quality changes and impacts as the water from the boreholes flowed through the ten acre wetland. Water was sampled from each of boreholes and from four locations downstream and two locations upstream from the discharges. Insitu measurements included pH, alkalinity, redox, dissolved oxygen, and conductivity. Samples were also taken back to the lab to test for Fe, Zn, Cd, Pb, Mg, and Ca using an Atomic Absorption Spectrophotometer. Additionally, some samples were used to determine sulfate concentrations using ion chromatography. It was found that the water quality of the mine water did change significantly as the water flowed downstream. However, it was determined that the change was due mainly to dilution from a storm water runoff drain located west of the boreholes. Also, another unlocated borehole may be at the site. Another sampling trip will be required prior to completion of this project due to the variability of the mine discharges and the rainfall in the area.

Publications/Presentations: Society of Wetland Scientists South Central Conference, October 2000, Little Rock Arkansas, Presentation

TITLE: Estimation of Soil Moduli Using the Dynamic Cone Penetrometer

Abstract: The dynamic cone penetrometer (DCP) is often used to determine near surface (less than 5 ft) stratigraphy below pavement structures. Some researchers have suggested that the penetration index, recorded as penetration per blow, can be correlated to the resilient modulus of the soil. In this study, DCP tests were performed on airport pavement sites in Oklahoma. The computed penetration index values were input into published correlation relationships to estimate resilient moduli of three different soils. The estimated resilient moduli were compared with moduli backcalculated from the spectral analysis of seismic wave (SASW) method. The analysis revealed that while the DCP profile matched the SASW profile as far as indicating changes in material integrity, the correlated DCP moduli did not match the SASW moduli.

ETHICS

Note that we did not have a formal ethics component sponsored by supplemental funds. However, we did have two group activities dedicated to ethics in engineering. First, an OU ethics professor gave a seminar on ethics as related to the professional and research environment, followed by a group discussion. It was given during the first week of the program so that the REUs could consider ethics during the course of their projects. Second, in conjunction with the REU Site in Industrial Engineering at the University of Oklahoma, we sponsored two seminars by Roger Boisjoly, who was a senior aerospace engineer at Morton Thiokol during the Challenger Space Shuttle disaster. The seminars were titled: "Ethical Decision Making in the Engineering Workplace" and "The Space Shuttle Challenger Disaster: A Model for Changing Workplace and Career Ethics."

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