PhD, University of Cincinnati, 1999, Engineering : Environmental Engineering

Increasing regulatory pressure for VOC emissions reduction has accelerated the development of more cost effective VOC air pollution control (APC) technologies. Biofiltration is a viable technology to fill this role, for the purification of air streams polluted with biodegradable VOCs. In the biofilter, these pollutants diffuse from the air stream into a stationary mass of moist biological film, where they are oxidized by enzymatic catalysis at ambient pressures and temperatures. Properly operated, this natural, biological mineralization process will produce only benign by-products, such as inorganic salts, carbon dioxide, and water, with some additional biomass. Although research into the science and development of the technology of biofiltration has been performed for over fifteen years, biofiltration remains not widely accepted as a proven technology for VOC APC. This perception is especially true for applications treating high influent VOC concentrations and requiring high VOC removal efficiencies. This research was undertaken to develop a new, cost effective biofiltration technology which can reliably treat air streams polluted with high VOC concentrations and achieve very high removal (elimination) efficiencies. Investigations were made to evaluate different biological attachment media, in order to identify the medium most suited to such an application. Using this medium, a reliable biofiltration technology was developed and extensively tested, which can achieve the goal of reliably treating high concentrations of VOCs at high loadings with high removal efficiency. Techniques for the management and control of the accumulating by-product biomass were developed. Procedures are presented for the calculation of VOC solubility and biological kinetic parameters, at the biofiltration operating temperature. A procedure for estimating the upper limit for biofiltration for the influent air VOC concentrations is presented. A simple, explicit biofilter design equation was (open full item for complete abstract)

Committee: Makram Suidan (Advisor) Subjects:

Master of Science in Chemical Engineering, Cleveland State University, 2011, Fenn College of Engineering

Increasing gas prices, limited fossil fuel resources and U.S. dependence on foreign oil make research in alternative fuels a priority. The feasibility of producing fuels from microalgae is economically dependent on improvements in lipid productivity by the algae. The research presented here focuses on the development of a mathematical model to describe the biomass and lipid productivity in a continuously-operated photobioreactor (PBR) system. Five different cell lysing methods were evaluated for the purpose of improving the methods of analysis of lipid synthesis. The two most promising methods were found to be mortar and pestle and organic solvent cell fractionation methods. Four types of batch experiments were performed with Scenedesmus dimorphus to determine key reactor model parameters: maximum cell growth rate (µmax), yield (Yx/s), and Monod constant (Ks). Two of the experiments were performed with varying initial sodium nitrate concentrations, for the purpose of more accurately obtaining the Monod parameters. The data was analyzed using three methods: differential/linear least-square, initial substrate and nonlinear. Nearly all of the results had non-reliable error results because most data yielded an ill-conditioned Covariance Matrix. Based on the results obtained by initial substrate method, the Ks was determined to be about 0.005 +/ 0.01 g/L, the maximum growth rate to be 0.7+/- 0.1 day-1 and the yield to range between 1.2 and 2.7 gcell/gsubstrate. The values found in this research, although preliminary, were used to formulate an approximate steady-state model of a two- PBR system, with first reactor used for maximizing biomass and utilizing substrate, and the second reactor for accumulating lipids. The fed substrate concentration and the dilution rate of the first reactor were estimated to be (So and D here) 1g/L and 0.65 day-1 for optimal biomass productivity. The dilution rate obtained for the second reactor suggests that the volumes ratio of the 2nd t (open full item for complete abstract)

Committee: Joanne Belovich PhD (Committee Chair); Jorge Gatica PhD (Committee Member); Nolan Holland PhD (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy, University of Toledo, 2013, Biology (Ecology)

The growth and abundance of phytoplankton in freshwater lakes has long been attributed to the concentration of phosphorus (P), and this idea of P-limitation has been a paradigm accepted by limnologists. Hence, lake managers have relied on the strategy of reducing P to restore water quality of eutrophic lakes. Recently however, several researchers have proposed that nitrogen (N) is equally important as P, and have stated that the P paradigm has eroded. These researchers suggest that both P and N inputs need to be constrained. In spite of the evidence that suggests N-limitation, there are still several researchers that hold onto the paradigm that only P regulates phytoplankton biomass. Limnologists need more data to solve this hotly debate topic. The goal of this dissertation is to provide insights into the dual nutrient management strategy controversy by studying how western Lake Erie cyanobacteria responded to low concentrations of N and P. In western Lake Erie nitrate concentrations decrease throughout the growing season to very low levels. Nutrient enrichment bioassays conducted monthly during the summers of 2010 and 2011 indicated that N (and not P) constrains cyanobacterial growth during August and September when nitrate concentrations are very low. Experiments conducted during 2012 showed that N-limited cyanobacterial blooms are able to utilize many forms of N. However, nutrient dilution assays indicated that N-limitation could not be induced during early summer when P is the primary limiting nutrient. Following N-limitation, the cyanobacterial bloom shifted from Microcystis to the N-fixing Anabaena. Furthermore, during 2011, the concentration of the cyanotoxin microcystin was highly correlated with Anabaena biovolume. Genetic diversity of the Microcystis population was assessed during 2011 and showed that diversity was very similar spatially and temporally in spite of the wide range of N, indicating that Lake Erie Microcystis can survive in low N waters. Final (open full item for complete abstract)

Committee: Thomas Bridgeman Ph.D. (Advisor); Darren Bade Ph.D. (Committee Member); Scott Heckathorn Ph.D. (Committee Member); R. Michael McKay Ph.D. (Committee Member); W. Von Sigler Ph.D. (Committee Member) Subjects: Freshwater Ecology; Limnology; Microbiology