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Thesis (Ph. D.)--Columbia University, 1937. / Vita. Bibliography: p. 20.

Élimination de l'azote est obligatoire dans moderne usine de traitement des eaux usées (STEP) en raison de sa toxicité à la fois humaine et l'écosystème. Un niveau élevé d'azote peut provoquer une eutrophisation dans le système aquatique. Élimination de l'azote autotrophes qui combine nitritation partielle et Anammox est une technologie attrayante qui est approprié pour une grande force d'ammonium des eaux usées à faible teneur en carbone organique. Toutefois, le ralentissement de la croissance extrême des bactéries Anammox avec le temps de 9-13 jours doubler entrave la pleine application de l'échelle. L'objectif de cette recherche était d'étudier la faisabilité et la stratégie opérationnelle de l'enrichissement Anammox de boues conventionnelle aérobie (réacteur ASR), la dénitrification des boues (Réacteur DSR) et boue anaérobie (réacteur ANR) en utilisant réacteur biologique séquentiel (SBR). Anammox processus a été établi avec succès en DSR avec une élimination de l'azote total d'environ 80% sous le contrôle strict de l'oxygène au bout de 150 jours, ce qui est confirmé par la composition chimique de l'influent / effluents ainsi que l'analyse microbienne. Sous la même condition opérationnelle, ANR atteint seulement 20-30% d'élimination de l'azote total. Avec un temps plus court de rétention hydraulique (HRT) et de contrôle d'oxygène insuffisante, ASR a atteint 50-60% du total élimination de l'azote après 240 jours. Tous les réacteurs ont connu la fluctuation des performances au cours du processus d'enrichissement, qui est censé être la conséquence de facteurs inhibiteurs tels que l'oxygène dissous, sans nitrites et l'ammoniac libre ainsi que les bactéries coexistantes indésirables qui sont en concurrence pour le même substrat. L'électrophorèse sur gel de gradient dénaturant (DGGE) bande à partir des échantillons d'ADN amplifiés extraites ASR lors de l'étape d'enrichissement différente montre une nette évolution de la composition microbienne. Substances polymères extracellulaires (EPS) de différents biomasse Anammox ont été extraites et caractérisé par analyse quantitative et qualitative pour enquêter sur sa corrélation avec le processus d'enrichissement dans un bioréacteur de l'échelle du laboratoire. Une diminution de la protéine au polysaccharide (PN / PS) rapport et une augmentation du rendement total d'extraction EPS ont été observés au cours du processus d'enrichissement. La matrice à trois dimensions excitation d'émission (3D-EEM) a montré un endroit similaire des pics de fluorescence pour tous les échantillons tandis que les échantillons avec des bactéries Anammox possèdent deux pics distincts dans le bas de gamme d'onde d'excitation. Pics multiples excitation peuvent se produire comme en témoigne la fluorescence identique chromatogramme après chromatographie d'exclusion de taille (SEC) à séparation d'excitation / émission de 221/350 nm et 280/330 nm. Rayons ultraviolets (UV) absorbance à 210 nm a été enregistrée en même temps que la détection de fluorescence à une excitation / émission 222/300 nm de longueur d'onde, 221/350 nm et 280/330 nm après séparées par SEC. Avec l'enrichissement de bactéries Anammox, chromatogramme UV montré une augmentation en intensité et en nombre de pics, alors que chromatogrammes fluorescence ont montré nombre maximal similaire et seulement augmentent en intensité. Une augmentation de l'hydrophobie a été observée au cours du procédé d'enrichissement. Les résultats de cette étude sont attendus pour étendre la connaissance de l'évolution du processus d'enrichissement Anammox EPS ainsi que de fournir nouvelle approche pour la caractérisation des EPS extraites de Anammox boues / Removal of nitrogen is mandatory in modern wastewater treatment plant (WWTP) due to its toxicity to both human and the ecosystem. A high level of nitrogen may cause eutrophication in aquatic system. Autotrophic nitrogen removal which combines partial nitritation and Anammox is an attractive technology which is suitable for high Ammonium strength wastewater with low organic carbon content. However the extreme slow growth of the Anammox bacteria with doubling time of 9-13 days hinders its wide full scale application. The aim of this research was to investigate the feasibility and operational strategy of Anammox enrichment from conventional aerobic sludge (Reactor ASR), denitrification sludge (Reactor DSR) and anaerobic sludge (Reactor ANR) using sequencing batch reactor (SBR). Anammox process was successfully established in DSR with a total nitrogen removal of approximately 80% under strict oxygen control after 150 days which is confirmed by chemical composition of the influent/effluent as well as microbial analysis. Under the same operational condition, ANR reached only 20-30% total nitrogen removal. With a shorter hydraulic retention time (HRT) and insufficient oxygen control, ASR reached 50-60% total nitrogen removal after 240 days. All the reactors experienced fluctuating performances during the enrichment process, which is believed to be the consequence of inhibitory factors such as dissolved oxygen, free nitrite and free ammonia as well as undesirable coexisting bacteria which compete for the same substrate. The denaturing gradient gel electrophoresis (DGGE) band from the amplified DNA samples extracted from ASR during different enrichment stage shows a clear evolution of the microbial composition. Extracellular polymeric substances (EPS) from different Anammox biomass have been extracted and characterized by quantitative and qualitative analysis to investigate its correlation with the enrichment process in a lab scale bioreactor. A decrease of protein to polysaccharide (PN/PS) ratio and an increase in total EPS extraction yield were observed during the enrichment process. The three dimensional excitation emission matrix (3D-EEM) showed similar location of the fluorescence peaks for all samples while samples with Anammox bacteria possess two distinct peaks in the low excitation wavelength range. Multi-excitation peaks may occur as evidenced by the identical fluorescence chromatogram after size exclusion chromatography (SEC) separation at excitation/emission 221/350 nm and 280/330 nm. Ultraviolet (UV) absorbance at 210 nm was recorded simultaneously with fluorescence detection at excitation/emission wavelength 222/300 nm, 221/350 nm and 280/330 nm after separated by SEC. With the enrichment of Anammox bacteria, UV chromatogram showed increase in both intensity and number of peaks, whereas fluorescence chromatograms showed similar peak number and only increase in intensity. An increase of hydrophobicity was observed during the enrichment process. The results of this study are expected to extend the knowledge of EPS evolution of Anammox enrichment process as well as providing novel approach for the characterization of EPS extracted from Anammox sludge

Azotobacter vinelandii, grown with ammonium as a nitrogen source, was shown to possess an active transport system which could concentrate ammonium 44 to 58 fold. Ammonium uptake was inhibited by the glutamate analog methionine sulfone. The properties of the ammonium uptake system (transport and metabolism) were investigated using the ammonium analog methylammonium. The uptake of methylammonium was inhibited by arsenate indicating that phosphate bond energy was required. Methylammonium uptake was also inhibited by the electron transport inhibitor, cyanide, and the uncoupler, carbonyl cyanide- m-chlorophenyl hydrazone. However, it was shown that these agents served to deplete ATP pools in A. vinelandii. Uptake of methylammonium was sensitive to a Tris-Mg⁺⁺ shock treatment suggesting the possible involvement of a periplasmic binding protein, however, methylammonium-binding activity was not found in periplasmic extracts. A. vinelandii was shown to exhibit a positive chemotactic response toward ammonium as well as acetate, glucose and sucrose. Comparison of outer membrane proteins from nitrogen-fixing cells and ammonium-grown cells revealed the production of a 44,000 dalton protein in membranes from nitrogen-fixing cells. Inner membranes from nitrogen-fixing cells contained a 41,000 dalton protein which was present in low amounts in the membranes of ammonium-grown cells. It was shown that the outer membranes of ammonium-grown cells contained a major protein which was "heat modifiable" in that its mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis was determined by the temperature of solubilization prior to electrophoresis. Methylammonium was shown to be metabolized to N-methylglutamine. Strain JK301, an L-methionine-D,L-sulfoximine-resistant mutant of A. vinelandii, was unable to catalyse N-methylglutamine synthesis in vivo or in cell-free extracts and lacked detectable methylammonium uptake activity. Glutamine synthetase in cell-free extracts of JK301 had a Km for glutamate approximately three-fold higher and a Vmax approximately fourfold lower than enzyme from the wild type strain. It was concluded that methylammonium uptake reflects, in part, metabolism to N-methylglutamine by glutamine synthetase. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

This thesis studies the effects of certain organic compounds upon the bacterial deposition of ferric hydroxide from ferric ammonium citrate.

Organically modified montmorillonite has been extensively used as nanofiller in studies of polymer layered silicate nanocomposites, promising materials for today's automotive industry because the nano-materials reduce the overall weight of vehicle. However, industrial applications have not followed suit primarily due to cost/performance issues. Supercritical carbon dioxide is promising as an aid in the production of a fully exfoliated polymer layered silicate nanocomposite but has not been fundamentally studied in this regard at present. As the first stage in studies of using supercritical carbon dioxide for aiding the production of thermoplastic elastomer nanocomposites, this thesis investigates the influence of this unique supercritical fluid on the microstructure and surface chemistry of five organically modified clays. Four alkyl-based quaternary ammonium surfactants with different number and length of chains attached and one aromatic quaternary ammonium surfactant were chosen to vary the degree of C02-philicity exhibited by the organoclay. In a high pressure batch vessel, the different organoclays were suspended in the supercritical solvent at temperatures of 50°C and 200°C and pressures of 7.6 MPa and 9.7 MPa for a fixed time and then removed after depressurization at 0.2 MPa/s or 4.8 MPa/s. The structures of these treated clays were characterized by XRD, TEM, DSC, TGA, FT -IR, and SEM, and their chemical properties were analyzed by various methods including atomic absorption spectroscopy, and contact angle measurement. The potential role of water to favor the interaction between scC02 and an organoclay was also investigated. Solute-solvent interactions plasticized the organic modifier while suspended in the supercritical fluid, which resulted in greater chain mobility and further cation exchange. The results indicate that surfactants exhibiting a paraffin-type conformation within the galleries of the clay were most likely to experience significant basal expansion, provided the tilt angle was not already close to being perpendicular to the silicate surface. For those organoclays demonstrating basal expansion, it was noted that the resulting particle size was increased due to enhanced porosity. Water proved useful in clay expansion in certain cases and primarily while operating conditions allowed the co-solvent to remain adsorbed to the clay surface. / Thesis / Master of Applied Science (MASc)

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