▼ The Baffled Flask Test (BFT) was developed at the Andrew W. Breidenbach Environmental Research Center in the National Risk Management Research Laboratory, a division of the U.S. Environmental Protection Agency’s Office of Research and Development. This test will soon be adopted as the official method for evaluating oil spill dispersants. A dispersant must meet the minimum requirements of the decision rules set forth by the official method to be listed on the National Contingency Product Plan Schedule (NCPPS) for use during an oil spill event. Two priority studies were conducted with the BFT. After the explosion of the Deepwater Horizon Oil drilling rig at the exploratory Maconda Well, U.S. EPA was asked to evaluate the eight dispersant products currently listed on the NCPPS, which had qualified under the current method, The Swirling Flask Test (SFT). There were three separate projects: 1) in vitro analyses to determine levels of cytotoxicity and endocrine disruption activity, 2) toxicity testing of dispersants alone, Louisiana Sweet Crude alone, and dispersant – oil mixtures using mysid shrimp and inland silverside fish, and 3) this lab, determination of dispersant effectiveness at two temperatures, 25 °C (the temperature on the surface of the Gulf) and 5 ° C (the temperature at the wellhead). The results showed that only three products gave satisfactory results at both temperatures. Presumably due to the low viscosity and density of South Louisiana Crude, temperature did not cause a significant difference in performance. Final Dispersant Effectiveness (LCL95DE, lower 95% confidence level after correction for natural dispersion) ranged from 11% to 78%. The other study was a request from the Department of the Interior’s Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE), formerly known as Minerals Management Service (MMS). They funded a study to compare four different bench scale tests with results obtained from their large scale wave tank at Ohmsett, The National Oil Spill Response Test Facility in Leonardo, NJ. All facilities will test the same twenty oils using Corexit 9500 at 15 ° C to determine if any of the tests are predictive of field performance. For comparison purposes in our study, the two oils currently in use by the BFT and SFT protocols plus another reference oil were added. The twenty oils ranged in density from 0.848 to 0.968 g/mL (35.03° to 14.39° API gravity) and kinematic viscosity from 9 to 32,326 cSt. Categorizing them by density, there are 2 light crudes, 6 medium crudes and 12 heavy crudes. Using Fingas’ definition (1990), by kinematic viscosity, there are 1 very light crude oil, 4 light crudes, 3 medium crudes, and 12 heavy crudes. Final Dispersant Effectiveness (LCL95DE) ranged from 3.4% to 77.1%. The 3 added reference oils, are by density – 2 lights and a medium and by kinematic viscosity – 1 very light and 2 light crudes. Their final Dispersant Effectiveness ranged from 64.8% to 93%. The results correlated to the viscosity of the oil with an R² of 0.84. Advisors/Committee Members: Suidan, Makram.

▼ Drinking water utilities use free chlorine or monochloramine (NH2Cl) as secondary disinfectants, which react with natural organic matter to form disinfection by-products (DBP). To reduce DBP concentrations and comply with the USEPA Stage 1 and 2 Disinfectant and DBP rules, some utilities have or are considering a switch from free chlorine to NH2Cl for secondary disinfection. However, ammonia (NH3) added to form NH2Cl may lead to nitrification and subsequent disinfectant residual loss. To better understand distribution system (DS) nitrification, the current research simulated long-term (2.5 years) chloraminated DS operation using two lab-scale annular reactors fed dechlorinated tap water supplemented with increasing temporal influent NH2Cl concentrations (0.0 to 3.2 mg Cl2 L-1) and Cl2:N mass ratios (0:1 to 3.2:1). Reactor performance was chemically monitored [pH, temperature, dissolved oxygen, NH3, nitrite, nitrate, NH2Cl, and trihalomethanes (THMs)] to allow evaluation of the nitrification index (NI) that accounts for the balance between ammonia-oxidizing bacteria (AOB) growth and inactivation. In addition, the AOB community was characterized for each influent NH2Cl concentration using AOB targeted (amoA gene) cloning and sequence analysis on (1) propidium monoazide treated (viable) and (2) untreated total (viable and non-viable) samples. In practice, increasing NH2Cl is usually ineffective to stop active nitrification, but in this study, active nitrification was halted when the influent NH2Cl concentration reached 3.2 mg Cl2 L-1 (approximately 3 mg Cl2 L-1 NH2Cl residual). The calibrated NI was successful in simulating this occurrence and indicated AOB inactivation was mainly due to THM cometabolism product toxicity and NH2Cl inactivation. The current sequencing results indicated that (1) viable AOB were detected with 0 to 1.5 mg Cl2 L-1 NH2Cl residual (Period 0 through Period 2.7c), (2) viable and total samples detected Nitrosomonas europaea and N. oligotropha related AOB and (3) N. oligotropha became the persistent viable AOB as NH2Cl increased. Previous chloraminated DS sequencing has shown N. oligotropha dominance, but no viability assessment was conducted. Overall, this study supported N. oligotropha’s importance and NI’s ability to predict nitrification. Advisors/Committee Members: Boccelli, Dominic.

▼ The fate of seven steroids: estrone (E1), estradiol (E2), estriol (E3), ethinylestradiol (EE2), testosterone (TEST), androstenedione (AND), and progesterone (PROG), in the presence of synthetic wastewater was studied in order to establish the role abiotic processes play in the elimination of these chemicals from the environment. Comprehension of these mechanisms will foster the optimization of the existing wastewater treatment technologies and the development of sustainable alternatives. Distinctive behavior was encountered for the target compounds in accordance with their chemical structure, hence, different physico-chemical properties and reactivity. Estrogenic compounds, comprising E1, E2, E3 and EE2, were found to undergo a catalytic transformation when contacted with a model vegetable material present in the synthetic wastewater. This transformation occurred in the absence of biological and enzymatic activity. On the other hand, the concentration of TEST, AND, and PROG stayed constant and in agreement with the spiked amount. The fastest transformation rate corresponded to E3, the least hydrophobic compound in the study. This may indicate that the catalytic reaction occurred in the aqueous phase. The contribution of steric and electronic factors, such as critical oxidation potential, in the reaction rate cannot be discarded; consequently, the hypothesis of a surface catalyzed reaction cannot be rejected. The use of 14C4-estradiol (14C-E2) as model estrogenic compound corroborated the occurrence of a catalytic reaction, most likely through an oxidative coupling mechanism. Under oxic conditions, the mass balance for radioactivity was closed after extended experimental periods (72 h), while the concentration of 14C-E2 measured by Liquid Chromatography coupled with a Triple Quadrupole Mass Spectrometer (LC/MS/MS) did not match the spiked one when analyzed independently in liquid and solid phases. Furthermore, radioactivity was found to distribute in the aqueous phase as well as extractable and non-extractable solids, suggesting that phenoxy radicals formed on the phenolic ring of 14C-E2 could react among themselves (to form dimers), with the functional groups present on the surface of the lignin-type vegetable model material (resulting in covalent bonded matter), and with other chemicals species in the solution. 14C4-estrone was also monitored in this study, but it was not detected in any sample. Behavior encountered under anoxic conditions emphasized the role of molecular oxygen in the catalytic process. In the absence of oxygen, the reaction was completely halted; this was confirmed by the closure of the mass balance of 14C-E2, which was performed by radioactivity and LC/MS/MS analyses. This indicated that estrogens were transformed in an oxidation reaction catalyzed by some vegetable matter component and in which the dissolved oxygen acted as oxidant. Preliminary investigations suggested that manganese oxides could be acting as catalyst in this scenario. Advisors/Committee Members: Suidan, Makram.

▼ The kinetics and ecological impacts of the aerobic biodegradation of vegetable oils in contaminated aquatic environments were studied in respirometric microcosms at different oil loadings (100, 333, and 1,000 gal acre-1) and mixing regimes (fully, moderately, and non-mixed microcosms). No significant difference in the extent of oil biodegradation was observed between the fully and moderately mixed microcosms at 100 and 333 gal acre-1 loadings, indicating minimal influence of enhanced mixing in these cases. Furthermore, comparable oxygen uptake rates were measured initially in the moderately and non-mixed microcosms at the 100 and 333 gal acre-1 loadings, suggesting an initial dependence of the microbial activity on the oil surface available for emulsification rather than on the oil concentration. Regardless of the mixing condition, reduced initial oxygen uptake rates were measured at 1,000 gal acre-1 loading and were associated with an initial oxygen mass transfer limitation. The results of the Microtox® assay showed no major toxicity at the 100 gal acre-1 loading. Furthermore, oxygen was not completely depleted from the water column at this oil coverage. At higher oil loadings, oxygen was fully depleted from the mixed and non-mixed water columns. A transient toxicity in the aqueous phase was observed in the case of the moderately mixed microcosms at 333 gal acre-1 and was maintained at moderate levels (EC50 ~30%) in the non-mixed microcosms. A substantial increase in toxicity (EC50 ~10 %) was observed in both mixing conditions when the initial oil loading was increased to 1,000 gal acre-1. Furthermore, the effect of antioxidants on the fate and impacts of vegetable oils in contaminated aquatic media was investigated. Respirometric experiments on the effect of increasing concentrations of butylated-hydroxytoluene (BHT) (0, 50, 100, 200, 400, and 800 ppm) on the biodegradability of glyceryl trilinoleate (333 gal acre-1), revealed the formation of intractable rigid polymers unavailable for bacterial degradation in all BHT treatments and particularly in the microcosms not supplemented with the antioxidant. In this case, limited oil mineralization was observed after 19 weeks of incubation (41%) compared to the microcosms supplemented with BHT (> 67 %). In these microcosms, no significant difference in the achieved oil mineralization was observed with increasing BHT concentrations, suggesting minimal additional protective effect of BHT above 50 and up to 800 ppm. In addition, the effect of BHT on the biodegradability and toxicity of purified canola oil (333 gal acre-1) was investigated in the absence and presence (200 ppm) of the antioxidant. Substantial oil mineralization was achieved after 16 weeks of incubation (> 77%) and was not significantly different between the two BHT treatments. Furthermore, for both treatments, a transient toxicity was observed and was attributed to the combined effect of toxic biodegradation intermediates and autoxidation products. Autoxidation in the microcosms initially supplemented with the BHT, was supported by the disappearance of the antioxidant after only 2 weeks of incubation. Intractable solid polymers were formed in all biotic microcosms and were attributed to an interaction between the oil autoxidation products and the degrading biomass rather than to oil polymerization. Advisors/Committee Members: Suidan, Makram.

▼ The main objective of this study is to create a baseline emission for University of Cincinnati which will be directly usable information for campus sustainability planning as well as to other research and campus administration professionals implementing sustainability as part of their own planning efforts. Clean Air Cool Planet (CA-CP) Campus Carbon Calculator version 5.0 is the model used for calculating the carbon footprint for the university as a part of the American College and University Presidents Climate Commitment (ACUPCC). Various other carbon footprint accounting tools, techniques, and guidelines competitive to CA-CP Campus Carbon Calculator are also used to calculate the carbon footprint of university to ensure credibility of the results from CA-CP Campus Carbon Calculator. Comparisons and evaluations are also done, to know how different techniques impact the final results. The study also helps us determine important parameters which effect the emissions. It also provides a sensitivity analysis on the various data inputs to estimate the impact of the data quality on the results using University of Cincinnati as a test case. It was estimated that on annual basis, University of Cincinnati emits an average of approximately 315,000 MTCO2e. Annually there is an approximate increase of 3 percent since 2004. Overall, University of Cincinnati’s carbon footprint has increased by 16.5 percent from 288,723 MTCO2e for fiscal year 2004 to 336,273 MTCO2e for fiscal year 2008. Purchased electricity and on-campus stationary sources are the largest source of greenhouse gas emissions and comprise 90 percent of the total carbon footprint for fiscal year 2008. A significant difference of 13 percent was observed between the highest and lowest estimating tools. Advisors/Committee Members: Keener, Timothy.

▼ The world is experiencing fossil fuel depletion, global warming and environmental deterioration due to the overuse of fossil fuels. Biodiesel, as an alternative fuel, is considered as part of the solution. Biodiesel has experienced rapid development and commercialization in the past decade, and the technology for biodiesel production has greatly improved in handling multiple feedstocks. But the development of the biodiesel industry is still facing challenges. The major obstacle to the wide use of biodiesel is that biodiesel is not cost-competitive compared with diesel fuels. The industry is constantly searching for low-cost, or even no-cost feedstocks. Therefore, trap grease can potentially serve as a promising biodiesel feedstock to boost the biodiesel industry. Trap grease is a mixture of oils, food debris and kitchen wastes. It is generated in grease traps in restaurants. In most municipalities in the US, trap grease, after being pumped out from grease traps by grease haulers, is either sent to wastewater treatment plant or directly to landfills. An intensive literature review has been conducted and the following facts have been obtained. In the US, grease is the number one cause of clogging of public sewers, which results in costly sanitary overflow or combined sewer overflows. Various utilization ways of trap grease include composting, land application, anaerobic co-digestion, making biodiesel, combustion, incineration and rendering, etc. If trap grease is utilized as a feedstock for biodiesel production, it is not only beneficial to the biodiesel industry, but also helps solve the trap grease disposal issue. However, the challenge lies in the extraction of the oil fractions from this highly heterogeneous low grade feedstock. The goal of this study is to evaluate the feasibility of a community scale conversion of trap grease to biodiesel. Trap grease sample used for this study was obtained from the Metropolitan Sewer District of Greater Cincinnati (designated as MSD-TG). The MSD-TG mainly consists of water (58.94%), free fatty acids (FFAs) (20.69%) and unextractable part/solids (18.17%), with the lipid part of the MSD-TG being almost all FFAs. This study uses waste cooking oil (WCO) to extract the oil faction from the MSD-TG. WCO is also a low-cost biodiesel feedstock oil and using WCO as the solvent removes the solvent recovery step in the pretreatment process. The optimum extraction conditions were studied. It was found that 60° is the optimum extraction temperature. And at 60°, the optimum extraction duration is 90 minutes and the optimum extraction ratio is 4:1 (for every 10g of the MSD-TG 40mL (36g) of WCO is used). The extraction performance of WCO was evaluated by comparing it with three other organic solvents, methanol, hexane and isopropyl alcohol/hexane (2:1, v/v). WCO shows comparable performance among the four solvents. Based on the survey from trap grease haulers, the quantity of the grease trap waste (as semi solids) generated in Cincinnati is estimated to vary from 1.48 to 3.97 million pounds annually. Advisors/Committee Members: Lu, Mingming.

▼ For years, silver ion has been used in the water professions and medical fields as an antimicrobial agent to control the harmful microorganisms for years. In the past few years, emerging nanotechnologies have even created more silver-ion applications by using nanosilver as a bactericide in consumer goods. This increased attention on silver ion as an antimicrobial agent reveals an urgent demand for understanding how microorganisms respond to silver-ion toxicity, but the silver-resistance mechanisms of microorganisms are only partially known. Thus, a comprehensive understanding of the silver-resistance mechanisms of microorganisms is essential. This current research studied the putative silver-resistance/adaptation mechanisms of Gram-negative microorganisms in different physiological conditions. The central hypothesis of this research is that ¬the microorganisms could use their own heavy-metal-related genes to exclude silver ion either in the planktonic or the biofilm state, and the silver-resistance mechanisms would be decided by the physiologic states. To test the central hypothesis, this study selected two Gram-negative microorganisms, Escherichia coli and Pseudomonas aeruginosa, cultivated in either the batch or the biofilm-annular reactor. The microorganisms were challenged by silver ion and analyzed the genetic responses of these two microorganisms against silver-ion toxicity by using the whole-genome microarray and relative-quantitative real-time polymerase-chain reaction analyses. The results of this research suggested that 1) The sessile-biofilm P. aeruginosa can adapt to the silver-ion toxicity and grow resiliently after being exposed to silver ion over a long period of time; 2) Copper-resistance genes are essential in silver-resistance/adaptation mechanisms of Gram-negative microorganisms; 3) Some other heavy-metal functional genes were involved in silver-resistance/adaptation mechanisms, but the involvements of these genes were determined by the physiological conditions and microbial species; 4) Microorganisms suffered severe oxidative stresses induced by silver ion because this study observed whole sets of the oxidant-defense-mechanism genes being up regulated (except the superoxide-dismutase genes in the sessile biofilm of both E. coli and P. aeruginosa) in response to silver-ion challenges; 5) E. coli can tailor expressions of resistance genes delicately to respond to silver-ion toxicity in different growth phases of the planktonic condition; and 6) The microorganisms would respond to the silver-ion toxicity differently on gene-expression levels, but they did share certain core resistance molecular functions. The findings of this current study provided novel information on how Gram-negative microorganisms in different physiological conditions responded to the silver-ion toxicities. There were common genetic responses among them, but the different genetic responses varied by the different physiological conditions. The results strongly validated the central hypothesis of this research. More importantly, this research showed that the sessile-biofilm P. aeruginosa grew resiliently as it was exposed to silver ion over 51 days. This discovery put into doubt the current applications of using silver ion as a disinfectant in the water profession. Advisors/Committee Members: Oerther, Daniel.