Anammox is one of the main processes discovered quite recently for removal of ammonium from wastewater. Anammox process is cost effective, in that low energy and carbon source is needed. Partial nitritation is a perquisite for anammox in wastewater treatment for removal nitrogen and therefore partial nitritation/Anammox technology is studied substantially and applied in full-scale. However, the technology at present can only be used to treat high rich ammonium streams. Application of Anammox for treatment of low ammonium wastewater is not possible because of low yield of Anammox bacteria. The study aimed at devising strategies for using the Anammox technology to treat wastewater streams with low concentration of ammonium nitrogen. The objective was to get systems that could concentrate ammonium from low ammonium waste streams, so as to be able to treat it with partial nitritation/Anammox process. Two methods were used to concentrate ammonium: ion exchange and reverse osmosis. Ion exchange method was used to concentrate UASB effluents of about 24 - 40 mg NH4-N/l to 188 - 367 mg  NH4-N/l respectively which is about 9 times the initial concentrations. At VRF 5, 163 mg  NH4-N/l concentrate was attained from 41.8 mg  NH4-N/l RO feed. Results also showed that concentrates from both methods are able to be treated with partial nitritation/Anammox technology. However it took more than 32 hours to complete treatment of ion exchange concentrates while it took less than 24 hours to finish the partial nitritation/Anammox process of RO concentrates. The longer time taken can be attributed to high salinity of the concentrates which is as a result of NaCl which was used for regeneration in ion exchange process. Both ion exchange and reverse osmosis are viable methods for concentrating ammonium from UASB effluents. Dissolved oxygen was very important factor that influenced the biological process.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第18330号 / 農博第2055号 / 新制||農||1022(附属図書館) / 学位論文||H26||N4837(農学部図書室) / 31188 / 京都大学大学院農学研究科応用生物科学専攻 / (主査)教授 荒井 修亮, 教授 山下 洋, 准教授 笠井 亮秀 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

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Dissolved oxygen (DO) depletion in a water body is governed by two primary mechanisms: biological oxygen demand (BOD) from the water column, and sediment oxygen demand (SOD) from sediments. SOD is the dominant oxygen sink in many water bodies; measurements show as much as 95% of oxygen consumption as attributable to SOD (Truax, Shindala, & Sartain, 1996). Measuring SOD in surface water impoundments is an essential component in evaluating and an important input for modeling the health of a water body. Traditional SOD measurement methods are difficult in deeper waters, such as in reservoirs or lakes, because traditional SOD measurement chambers require direct placement. The goal of this research was to modify an existing SOD chamber design to support deployment and recovery in depths in excess of 5ft, typically from a boat or other floating platform. The design required accurate DO measurements, taken unattended and recorded for several hours to several days, for SOD calculations and other parameters such as cation releases under anaerobic conditions. Using a previously designed chamber, I developed tools and methods to meet these requirements. DO data logger probes were purchased so that DO calculations could be taken without the need of surface support. To mount the chambers inside the previously designed chambers, a new mounting mechanism was designed and installed onto the chamber lids. Deployment and recovery methods and design were developed to ensure the chambers would be recoverable from a boat in deep waters. Previously, the unmodified chambers could not be deployed unattended because of the required power and data link with the surface. Here I present an easily replicated chamber design that allows for remote chamber placement and measurement of SOD in deep waters without the need of SCUBA or other specialized equipment that is traditionally required. The chamber design allows water to circulate through the chambers until they are placed and closed on the sediment bed, at which time the measurements start, ensuring correct initial conditions. During deployment, the data logger will log DO concentrations at predetermined intervals for several hours or days at a time. To recover the chambers, the researcher must only find the buoy attached to the rope and hoist the units back to the surface. Modifications and methods were tested and revised over the course of several months and dozens of tests. Experiments were conducted at various depths, ranging from 12–50ft, which showed the versatility of the chambers. Using this design, other researchers will be able to generate substantial amounts of SOD data at depths that will allow accurate SOD behavior to be included in models of water impoundments.

Gene therapy is advancing rapidly, with Recombinant Adeno-associated virus (rAAV) being investigated for potential use in treating cancer and neurological disorders. Plasmid DNA transfection and viral infection are standard methods for producing large-scale rAAV vectors. However, improving yield production requires careful monitoring and control of process state variables, which can be expensive and time-consuming. This thesis proposes a model predictive control (MPC) model that can efficiently monitor, predict, and optimize the final product by controlling state variables like DOT and temperature. The model relies on an unstructured mechanistic kinetic model designed explicitly based on rAAV upstream production. Monitoring viral vector production based on substrate or biomass concentration enhances bioprocess production efficiency. However, other state variables like dissolved oxygen (DO), pH, and temperature should also be considered. The objective of this thesis is to enhance cell growth in bioreactors by regulating dissolved oxygen and temperature levels using a Model Predictive Control (MPC) system. This model can be employed in different processes to enhance cell growth and examine the impact of control measures. The goal is to achieve a high cell density, increase productivity, and lower costs in a shorter duration. Simulink, a software tool developed by MATLAB, seamlessly integrates Ordinary Differential Equations (ODEs) to optimize bioprocesses in bioreactors. The Model Predictive Control (MPC) controller expertly regulates Dissolved Oxygen Tension (DOT) and temperature, thereby increasing cell growth concentrations. This sophisticated controller efficiently manages multiple variables simultaneously and exceeds the Proportional Integral Derivative (PID) controller. The model is straightforward to comprehend and promptly responds to anomaly data. To evaluate the suggested resolution, we conducted tests on both PID and MPC controllers by introducing measurement noise to the DOT. Our analysis indicated that MPC demonstrated superior performance based on the ISE (Integral of Squared Error), IAE (Integral of Absolute Error), and ITAE (Integral of Time-weighted Absolute Error), all of which were substantially higher for the PID controller. Regardless of changing conditions, MPC adeptly tracks the setpoint and optimizes the variable to enhance production efficiency.

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The Atlantic Meridional Overturning Circulation (AMOC) is thought to exert considerable influence over the climate via heat redistribution and carbon storage. Its repeated variations along with the regional and global climate during the last glacial cycle suggest that the state of the AMOC may be roughly divided into “warm,” “cold,” and “off” modes. The three modes correspond to the vigorous deepwater formation in the subpolar North Atlantic, a reduced deepwater formation, and the widespread disruption of the AMOC, respectively. Questions remain about the cause and response of AMOC perturbations in each of the three modes.Reconstruction of the burial flux of ice-rafted debris can resolve questions about the timing and rates of ice sheet calving, which may have been responsible for the “off” mode of the AMOC, given the association of freshwater forcing with AMOC strength. The first chapter quantified the flux of ice-rafted debris in a pair of cores collected from sites in the western North Atlantic. The results show higher ice-rafted debris flux during all Heinrich events and that the western North Atlantic fluxes were higher than the east. The data demonstrate that the Laurentide Ice Sheet played a role in all Heinrich events. A catastrophic last interglacial Laurentide outburst (LILO) event some 125,000 years ago (125 ka) may have contributed to abrupt climate change during the Eemian, when the AMOC was in the “warm” mode. The LILO event was previously proposed to be an analog of the Holocene 8.2 ka event. The second chapter investigated the age and chemical compositions of a layer of red sediments deposited across much of the Northwest Atlantic at 125 ka. The results provide strong support for the occurrence of the LILO event that was analogous to the 8.2 ka event in provenance, timing, and delivery. Little is known about the zonal (east/west) characteristics of the AMOC when in the “cold” mode during the Last Glacial Maximum. Authigenic uranium preserved in sediments is a sensitive redox tracer and can shed light on bottom water oxygen, carbon storage, and water mass distributions. In the third chapter, new and published authigenic uranium data were used to reconstruct deep ocean oxygenation. The compilation shows that lower-than-Holocene oxygen and correspondingly greater respired carbon storage were persistent features of the LGM in the deep North Atlantic. The eastern basin was substantially less well oxygenated than the west. A farther advance and greater infilling in the east of deep waters originating from the Southern Ocean may have caused the zonal difference. Alternatively, deep waters originating from the subpolar North Atlantic may have increased in their residence time in the eastern transect. Questions remain about the flux of freshwater necessary to induce the AMOC to enter the “off” mode. Existing estimates do not agree on the freshwater fluxes associated with Heinrich events. The fourth chapter uses compiled 230Thxs-based mass fluxes in the North Atlantic during the last glacial period to calculate the surge mass fluxes as a measure of the rate of ice-rafted debris deposition. The surge mass fluxes were then converted into freshwater fluxes. Freshwater fluxes for an arbitrarily defined 2000-year period and total freshwater volumes between 20° and 70° N were as high as 0.11 Sv and 6.9 × 1015 m³ during Heinrich event 4 and as low as 0.0012 Sv and 7.6 × 1013 m³ during Heinrich event 3. The relatively low freshwater fluxes we reconstructed for Heinrich events might suggest potentially a high sensitivity of the Atlantic Meridional Overturning Circulation to freshwater perturbations, although the freshwater volumes are in line with previous reconstructions. Our project represents the first time an attempt made to reconstruct the freshwater fluxes and volumes during all Heinrich events of the last glacial period.