Thesis (Ph. D - Hydrology and Water Resources) - University of Arizona. / Includes bibliographical references (leaves 259-280).

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Supervisors: Lynn E. Katz and Gerald E. Speitel Jr. Vita. Includes bibliographical references. Also available from UMI.

Over the last decade, luminescence measurements have been used primarily to detect and quantify specific organic pollutants and heavy metals, and in a few cases for monitoring microbial activity. In this study, a fiber-optic luminescence detection system was developed to examine the relationship between microbial activity and the resultant impact on biodegradation and transport of substrate in porous media. This system allows rapid, real-time, and non-destructive measurements of in-situ luminescence from a specific lux reporter microbial population in porous media. An understanding of the formation and dynamics of bioactive zones is very important for in-situ bioremediation applications because it is in these zones that the remediation process is optimal. This study also examined the location and size of a biologically active zone in response to changes in local substrate and electron acceptor availability. Results show that when DO was not a limiting factor, the bioactive zone encompassed the entire system. However, as the availability of DO became limiting for the higher-00 experiments, the size of the bioactive zone shrank and was ultimately limited to the proximity of the substrate source. Furthermore, a decrease in the size of the bioactive zone enhanced the rate of substrate biodegradation per unit area. This study also investigated the impact of several coupled factors including substrate concentration, pore-water velocity, and initial cell density on solute biodegradation and transport behavior for a system influenced by three stressors, microbial lag, microbial growth, and cell transport. Results showed that temporal changes in biodegradation potential, and therefore attendant substrate transport behavior, were influenced by microbial lag, growth, dissolved oxygen limitations, and cell elution. As a result, substrate transport behavior was non-steady except for relatively short residencetime conditions wherein substrate degradation exhibited quasi first-order behavior. Cell transport and elution was important, especially under significant growth conditions. Under such conditions, the majority of the cells in the system (60 to 90%) was distributed in the solution phase where most of the biodegradation took place. This study illustrates the complex behavior that can be associated with microbially mediated processes, and which should be included in solute transport models to accurately predict the fate of contaminants in the subsurface environment.

Thesis (Ph. D., Civil Engineering)--University of Idaho, April 2008. / Major professor: Steven Porter. Includes bibliographical references. Also available online (PDF file) by subscription or by purchasing the individual file.

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Dr. Frank E. Löffler; Committee Member: Dr. Joseph B. Hughes; Committee Member: Dr. Kurt D. Pennell; Committee Member: Dr. Lawrence J. Shimkets; Committee Member: Dr. Robert A. Sanford; Committee Member: Dr. Thomas DiChristina.

Thesis supervisor: Gene F. Parkin. Includes bibliographic references (p. 117-125).

Trichloroethene (TCE) is the most frequently detected organic contaminant in groundwater, is classified as a probable human carcinogen, and exhibits toxicological effects on the human endocrine, immune, developmental, and reproductive systems. While significant research efforts have been devoted to the development of strategies for remediating TCE-contaminated groundwater, their advancement is currently hindered by limitations in current methodologies for measuring in situ reductive dechlorination rates, especially for sorbing solutes. This dissertation describes the development, evaluation, and demonstration of a method for measuring in situ reductive dechlorination rates that utilizes single-well, "push-pull" test technology. Initial field tests indicated that trichlorofluoroethene (TCFE) could be used as a surrogate for TCE in push-pull tests since (a) TCE and TCFE were transported similarly and (b) TCFE underwent reductive dechlorination by a pathway analogous to that of TCE while retaining the fluorine label. Because TCFE and TCE experienced sorption at the selected field site, a novel data analysis technique called "forced mass balance" (FMB) was developed to obtain in situ transformation rates of sorbing solutes from push-pull test data. The FMB technique was evaluated by quantifying errors in rates derived by applying FMB to push-pull test data generated by a numerical model. Results from simulated tests indicated that an example in situ rate for the reductive dechlorination of TCFE, which was obtained by applying FMB to field data, was underestimated relative to the true in situ rate by 10%. The utility of the rate-determination method presented in this dissertation was demonstrated by using it to evaluate the effectiveness of a chemical amendment, namely fumarate, at enhancing in situ reductive dechlorination rates in TCE-contaminated groundwater. Reductive dechlorination rates increased following three consecutive additions of fumarate in all five of the tested wells. The development of the rate-determination method described in this dissertation advances the state of bioremediation technology because methods for measuring in situ transformation rates are needed to both assess the potential for natural attenuation and to quantify the effects of bioremediation techniques in the field. / Graduation date: 2003

A pilot scale demonstration of a biological permeable barrier was conducted in a pentachlorophenol-contaminated aquifer at a wood preserving facility. A permeable reactor was constructed to fit within a large diameter well. Arranged in series, a cylindrical reactor 24" x 36" (0.61 x 0.91m) (diameter x height) was partitioned to provide three biological treatment zones. Pentachlorophenol (PCP) biodegradation was evaluated under several environmental conditions using a mixed microbial consortium supported on ceramic saddles. Imitation vanilla flavoring (IVF), a mixture of propylene glycol, guaiacol, ethyl vanillin and sodium benzoate, served as the electron donor. In the absence of exogenous substrate, PCP was not degraded in the inoculated permeable barrier. Substrate addition under oxidizing conditions also failed to initiate PCP removal. Anaerobic conditions however, promoted in-situ PCP degradation. PCP reductive dechlorination resulted in the transient production of 3,4,5-trichlorophenol through sequential ortho dechlorinations. Continued carbon reduction at the meta and para positions resulted in 3,4-dichlorophenol and 3,5-dichlorophenol production. Complete removal of all intermediate degradation products was observed. Reactor operation was characterized through two independent laboratory and field companion studies. Experiments were conducted to evaluate (1) the effect of supplemental electron donor concentration (IVF) and (2) the effect of sulfate, a competitive electron acceptor on PCP reductive dechlorination. Results from laboratory and field conditions were consistent. (1) In the presence of an exogenous electron donor, PCP degradation was independent of supplemental donor concentration (10, 25, 50, 100 mg COD/L). However, a comparatively slower rate of PCP degradation was observed in the absence of electron donor. (2) The presence of sulfate was not inhibitory to PCP degradation. However, compared to systems evaluated in the absence of sulfate, slower rates of PCP transformation were observed. Passive operation and low energy requirements, coupled with potential contaminant mineralization suggest that the biological permeable barrier is a highly effective tool for subsurface restoration. / Graduation date: 2000

Graduation date: 1995

Chlorinated organic compounds are widely used in various industrial processes. Due to their high density and low water solubility, they are mainly utilized as cleaning solvents in dry cleaning operations, as well as semiconductor manufacturers. Many chlorinated organic compounds spilled sites contain residuals, which present in a pure liquid phase (dense non-aqueous phase liquids, DNAPLs). Trichloroethylene (TCE) is the most typical compound as a result. In situ bioremediation has been successfully used for the removal of TCE. This process has several advantages, such as relative simplicity, low cost, and potentially remarkable efficiency in contamination removal than others. By using the in situ bioremediation to remediate TCE contaminated groundwater, it must ensure (1) biodegradability of contaminants, and the presence of a competent biodegrading population of microorganisms, (2) presence of electron acceptors, and (3) environment condition and, nutrient sources. A field study for biodegradation TCE through molasses injection was conducted at the industrial trading estate in Kaohsiung City. The study included electronic products, semiconductor, nicety optical industry and so on. Molasses, nitrate and phosphate were introduced from injection well (BW1-1 and BW2-1) into aerobic and anaerobic groundwater contaminated site. In the aerobic zone, there were four wells being monitored: BW1-1, C029, BW1-2 and BW1-3. After 213 days of biostimulation treatment, TCE concentration detection results showed TCE concentrations in all wells monitored. BW1-1 and C029, there was a sharp decrease from 0.0853 mg/L to below the detection limit and from 0.1340 mg/L to 0.0038 mg/L. BW1-2 and BW1-3 showed a slight decrease from 0.0668 mg/L to 0.0211 mg/L and from 0.0323 mg/L to 0.0161 mg/L. After treatments, TCE concentrations in all wells monitored were dropped to 0.05 mg/L. In anaerobic zone, there were four wells being monitored: BW2-1, SW-4, BW2-2 and BW2-3. After 193 days of biostimulation treatment, TCE concentration detection results showed TCE concentrations in all wells monitored. BW2-1, SW-4, BW2-2 and BW2-3 all had a slight decrease from 0.0399 mg/L to 0.0043 mg/L, from 0.14603 mg/L to 0.0687 mg/L, from 0.1030 mg/L to 0.0365 mg/L and from 0.0492 mg/L to 0.0289 mg/L. According to the results from BIOCHLOR modeling, elevated aqueous concentration of chloroethenes with a classical reduction pathway for TCE leading to an accumulation of vinyl chloride and ethane. All the results revealed that bioremediation technology is one of the more feasible approaches to clean up TCE contaminated groundwater in this field.