Thesis (M.S.)--Florida State University, 2005. / Advisor: Dr. Tarek Abichou, Florida State University, College of Engineering, Dept. of Civil and Environmental Engineering. Title and description from dissertation home page (viewed June 8, 2005). Document formatted into pages; contains ix, 62 pages. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xvii, 342 p.; also includes graphics. Includes bibliographical references (p. 164-171). Available online via OhioLINK's ETD Center

With the significant potential of microalgae as a major biofuel source of the future, a considerable scientific attention is attracted towards the field of biotechnology and bioprocess engineering. Nevertheless the current photobioreactor (PBR) design methods are still too empirical. With this work I would like to promote the idea of designing a production system, such as a PBR, completely \emph{in silico}, thus allowing for the in silico optimization and optimal control determination. The thesis deals with the PBR modeling and simulation. It addresses two crucial issues in the current state-of-the-art PBR modeling. The first issue relevant to the deficiency of the currently available models - the incorrect or insufficient treatment of either the transport process modeling, the reaction modeling or the coupling between these two models. A correct treatment of both the transport and the reaction phenomena is proposed in the thesis - in the form of a unified modeling framework consisting of three interconnected parts - (i) the state system, (ii) the fluid-dynamic model and (iii) optimal control determination. The proposed model structure allows prediction of the PBR performance with respect to the modelled PBR size, geometry, operating conditions or a particular microalgae strain. The proposed unified modeling approach is applied to the case of the Couette-Taylor photobioreactor (CTBR) where it is used for the optimal control solution. The PBR represents a complex multiscale problem and especially in the case of the production scale systems, the associated computational costs are paramount. This is the second crucial issue addressed in the thesis. With respect to the computational complexity, the fluid dynamics simulation is the most costly part of the PBR simulation. To model the fluid flow with the classical CFD (Computational Fluid Dynamics) methods inside a production scale PBR leads to an enormous grid size. This usually requires a parallel implementation of the solver but in the parallelization of the classical methods lies another relevant issue - that of the amount of data the individual nodes must interchange with each other. The thesis addresses the performance relevant issues by proposing and evaluation alternative approaches to the fluid flow simulation. These approaches are more suitable to the parallel implementation than the classical methods because of their rather local character in comparison to the classical methods - namely the Lattice Boltzmann Method (LBM) for fluid flow, which is the primary focus of the thesis in this regard and alternatively also the discrete random walk based method (DRW). As the outcome of the thesis I have developed and validated a new Lagrangian general modeling approach to the transport and reaction processes in PBR - a framework based on the Lattice Boltzmann method (LBM) and the model of the Photosynthetic Factory (PSF) that models correctly the transport and reaction processes and their coupling. Further I have implemented a software prototype based on the proposed modeling approach and validated this prototype on the case of the Coutte-Taylor PBR. I have also demonstrated that the modeling approach has a significant potential from the computational costs point of view by implementing and validating the software prototype on the parallel architecture of CUDA (Compute Unified Device Architecture). The current parallel implementation is approximately 20 times faster than the unparallized one and decreases thus significantly the iteration cycle of the PBR design process.

Le traitement des effluents et eaux usées par bioréacteurs à membranes immergées (BAMI) permet d'obtenir une haute qualité de perméat par une dégradation biologique et une séparation physique. Néanmoins, le procédé de filtration est limité par l'influence de facteurs très complexes, en particulier le colmatage de la membrane. Le but du travail est de développer des modèles dynamiques et de simuler le procédé de filtration dans les BAMI. Le développement et la simulation des modèles ont été ciblés sur la description des rapports existants entre les variables les plus importantes du système, comme la pression transmembranaire (PTM), les matières en suspension (MES), les substances polymériques extracellulaires (SPE) et l'influence sur l'évolution du colmatage d'une aération syncopée, injectée à la surface de membrane, et sa synchronisation avec une filtration intermittente. Le modèle et les études d'optimisation du système ont été validé par voie expérimentale. / This thesis studies a submerged membrane bioreactor (MBR) technology that is used to treat effluents. We present in detail the modeling of this process, the validation of developed models, and the results of simulation and optimization carried out with the above mentioned models. The new contributions to scientific knowledge of this work are the following: - A new dynamic model that integrates for such systems, many of the variables and the main phenomena occurring during the process of filtration in MBR wastewater treatment. That constitutes an original contribution to the analysis and development of this technology. – The simulation allows to achieve the quantification of the influence and effect of aeration on the process (membranes fouling) and the influence of the sequencing of the filtration and coarse bubbles aeration cycles. All that takes into account the behavior of biomass, the generation of exopolymeric substances and inlet characteristics. The results provided by the model are validated by comparison with experimental results. – An optimization of MBR operating conditions using the experimental design for simulation, is reported based on the results obtained using the developed models / En la presente tesis se reflejan los estudios realizados en un biorreactor con membrana sumergida, tecnología que se utiliza para el tratamiento de efluentes residuales. Se presentan de forma detallada la modelación de este proceso, la validación de los modelos desarrollados, así como los resultados de la simulación y optimización realizados con los modelos. Entre los nuevos aportes al conocimiento científico del trabajo se encuentran los siguientes: - Un nuevo modelo dinámico que integra por primera vez, para estos sistemas, muchas de las variables y los principales fenómenos que ocurren durante el proceso de filtración y tratamiento de las aguas residuales utilizando los BMS. Lo cual constituye un aporte novedoso para el análisis y desarrollo de esta tecnología. - Se logró por primera vez cuantificar mediante simulación la influencia y el efecto de la aireación sobre el proceso de colmatación de las membranas, así como la influencia de la sincronización de los ciclos de filtración y aireación de burbujas gruesas. Todo esto tomando en cuenta el comportamiento de la biomasa, la generación de sustancias colmatantes y las características de la alimentación. Se validaron los resultados que ofrece el modelo mediante la comparación con resultados experimentales. - Se reporta por primera vez la optimización de las condiciones operacionales de un sistema BMS utilizando el diseño de experimento para la simulación, partiendo de los resultados obtenidos utilizando los modelos desarrollados

Conventional activated sludge-based wastewater treatment is an energy and resource-intensive process. Historically it has been successful at producing safely treated wastewater effluents in the developed world, specifically in places that have the infrastructure and space to support its operation. However, with a growing need for safe and efficient wastewater treatment across the world in both urban and rural settings, a paradigm shift in waste treatment is proving to be necessary. The sustainability of the future of wastewater treatment, in a significant way, hinges on moving towards energy neutrality and wastewater effluent reuse. This potential for reuse is threatened by the recent emergence and study of contaminants that have not been previously taken into consideration, such as antibiotics and other organic micropollutants (OMPs), antibiotic resistance genes, and persistent pathogenic bacteria. This dissertation focuses on investigating the use of anaerobic membrane bioreactor (AnMBR) technology for the sustainable treatment of municipal-type wastewaters. Specifically, a microbial approach to understanding biofouling and methane recovery potential in anaerobic MBR systems has been employed to assess different reactor systems’ efficiency. This dissertation further compares AnMBRs to their more widely used aerobic counterparts. This comparison specifically focuses on the removal and biodegradation of OMPs and antibiotics in both anaerobic and aerobic MBRs, while also investigating their effect on the proliferation of antibiotic resistance genes. Due to rising interest in wastewater effluent reuse and the lack of a comprehensive understanding of MBR systems’ effects on pathogen proliferation, this dissertation also investigates the presence of pathogens in both aerobic and anaerobic MBR effluents by using molecularbased detection methods. The findings of this dissertation demonstrate that membrane-associated anaerobic digestion processes have significant potential to improve the sustainability of wastewater treatment. This is exemplified by attributes of AnMBR systems associated with both increased system efficiency and wastewater reuse potential through methane recovery and lower abundance of effluent microbial contaminants, respectively. Overall, the studies collated in this dissertation have shown that understanding the microbial communities of AnMBRs can play a central role in further improving these attributes and in reducing the risks posed by emerging contaminants and pathogens in wastewater treatment systems.

The membrane bioreactor (MBR) is becoming increasingly popular for wastewater treatment, mainly due to its capability of producing high quality effluent with a relatively small footprint. However, high plant maintenance and operating costs due to membrane fouling limit the wide spread application of MBRs. Membrane fouling generally depends on the interactions between the membrane and, the activated sludge mixed liquor, which in turn, are affected by the chosen operating conditions. The present research study aimed to explore the process performance and membrane fouling in the membrane enhanced biological phosphorus removal (MEBPR) process under different operating conditions by, (1) comparing two MEBPRs operated in parallel, one with constant inflow and another with a variable inflow, and by, (2) operating the MEBPRs with different solids retention times (SRT). On-line filtration experiments were conducted simultaneously in both MEBPR systems by using test membrane modules. From the transmembrane pressure (TMP) data of the test membrane modules, it was revealed that fouling propensities of the MEBPR mixed liquors were similar in both parallel reactors under the operating conditions applied, although the fouling propensity of the aerobic mixed liquors of both reactors increased when the SRT of the reactors was reduced. Routinely monitored reactor performance data suggest that an MEBPR process with a varying inflow (dynamic operating condition) performs similarly to an MEBPR process with steady operating conditions at SRTs of 10 days and 20 days. Mixed liquor characterization tests were conducted, including critical flux, capillary suction time (CST), time to filter (TTF) and, bound and soluble extracellular polymeric substances (EPS) were quantified, to evaluate their role on membrane fouling. The tests results suggest that the inflow variation in an MEBPR process did not make a significant difference in any of the measured parameters. With decreased SRT, an increase in the concentrations of EPS was observed, especially the bound protein, and the bound and soluble humic-like substances. This suggests that these components of activated sludge mixed liquors may be related to membrane fouling. No clear relationship was observed between membrane fouling and other measured parameters, including critical flux, normalized CST and normalized TTF. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

京都大学 / 0048 / 新制・論文博士 / 博士(医科学) / 乙第13332号 / 論医科博第5号 / 新制||医科||7(附属図書館) / 大阪大学大学院生命機能研究科生命機能専攻 / (主査)教授 河本 宏, 教授 濵﨑 洋子, 教授 髙折 晃史 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

The limited availability of fossil resourses mandates the development of new energy vectors, which is one of the Grand Challenges of the 21st Century [1]. Biocatalytic energy conversion is a promising solution to meet the increased energy demand of industrialized societies. Applications of biocatalysis in the gas-phase are so far limited to production of fine chemicals and pharmaceuticals. However, this technology has the potential for large scale biocatalytic applications [2], e.g. for the formation of novel energy carriers. The so-called solid/gas biocatalysis is defined as the application of a biocatalyst immobilized on solid-phase support acting on gaseous substrates [3]. This process combines the advantages of bio-catalysis (green chemistry, mild reaction conditions, high specicity & selectivity) and heterogeneous dynamic gas-phase processes (low diffusion limitation, high conversion, simple scale-up). This work presents the modifications of a PID Microactivity Reference reactor in order to make it suitable for solid/gas biocatalysis. The reactor design requirements are based on previously published laboratory scale solid/gas systems with a feed of saturated vapors [4]. These vapors are produced in saturation flasks, which were designed and optimized during this project. Other modifications included relocation of the gas mixing chamber, redesigning the location and heating mechanism for the reactor tube, and heating of the outlet gas line. The modified reactor system was verified based on the Candida antarctica lipase B catalyzed transesterication of ethyl acetate with 1-hexanol to hexyl acetate and ethanol and results were compared to liquid-phase model reactions. Products were analyzed on line by a gas chromatograph with a flame ionization detector. C. antarc- tica physisorbed on silica particles produced a 50% conversion of hexanol at 40 C in the gas-phase. A commercial immobilized lipase from Iris Biotech produced 99% and 97% conversions of hexanol in similar experiments. This project achieved its goal to design, establish and successfully verify a solid/- gas biocatalysis reactor. Future work will target optimization of the reactor's operating conditions and the development of whole cell catalysts for energy production reactions. Potential experiments include the study of hydrogenolytic carbon dioxide reduction to methanol by free enzymes or methanogenic organisms [5], and the investigation of hydrogen production by water splitting of algae or cyanobacteria.

Several operational and environmental conditions can result in poor biogas yield during the operation of anaerobic digesters and anaerobic bioreactor landfills. Over time, anaerobic co-digestion and leachate blending have been identified as strategies that can help address some of these challenges to improve biogas production. While co-digestion entails the co-treatment of multiple substrates, leachate blending involves combination of mature and young landfill leachate. Despite the benefits attributed to these strategies, their impact on recirculating bioreactor landfill scenarios and anaerobic digesters requires further investigation. In the first phase of this thesis, an attempt to assess biogas production improvement from organic fraction of municipal solid waste in simulated bioreactor landfills through recirculation of blended landfill leachate was conducted. Real old and new leachate blends (67%New leachate:33%Old leachate, 33%New leachate:67%Old leachate) as well as 100%New and 100%Old leachate were recirculated through six laboratory-scale bioreactors using open-loop and closed-loops modes. Compared with the control bioreactor where 100% new leachate was recirculated and operated as a closed-loop, cumulative biogas production was improved by as much as 77 to 193% when a leachate blend of 33%New:67%Old was recirculated. Furthermore, comparison of the results from open-loop and closed-loop operated bioreactors indicated that there was approximately 28 to 65% more biogas in open-loop bioreactors. The Gompertz model applied to the methane data produced a better fit (R2 > 0.99) than first order and logistic function models. Leachate blending reduced the lag phase by almost half and thus helps in alleviating the ensiling during the start-up phase. In the second phase, a biochemical methane potential (BMP) assay was conducted to investigate the synergistic effect of percentage sewage scum addition; 10%, 20% and 40% (volatile solids basis) on biogas production during mesophilic co-digestion with various organic substrates viz; organic fraction of municipal solid waste, old leachate, new leachate and a leachate blend prepared from 67%old leachate and 33%new leachate under sub-optimal condition. Results show that the net cumulative bio-methane yield was improved with increased sewage scum percentage during co-digestion because of positive synergism. Meanwhile, the addition of 40% sewage scum to the individual co-substrates improved net cumulative bio-methane yield by 28% - 67% when compared to their respective mono-substrate digestion bio-methane yield. Furthermore, reactors containing leachate blends consistently produced more biogas over other sets because of blending. Kinetic modelling applied to the bio-methane production data shows modified Gompertz equation achieved a better fit with up to an R2 value of 0.999. Finally, co-digestion substantially reduced the lag time encountered during mono-digestion. In the last phase, the biomethane potential involved in the ACo-D of sewage scum, organic fraction of municipal solid waste was investigated in this phase using either thickened waste activated sludge or leachate blend (67%old leachate and 33%new leachate) as a tertiary component. Compared to the mono-digestion of TWAS, results shows that biomethane yield was enhanced in by as much as 32 - 127% in trinary mixtures with SS and OFMSW mainly due to the effect of positive synergism. Furthermore, LB addition improved biomethane production in trinary mixtures of SS:LB: OFMSW by 38% than in corresponding trinary mixtures of TWAS. Whereas an optimal combination of 40%SS:10%TWAS:50%OFMSW and 20%SS:70%LB:10%OFMSW produced the highest biogas yield of 407mL.gVS-1 and 487mL.gVS-1 respectively. The application of the first order model showed that lower hydrolysis rates promoted methanogenesis with k = 0.04day-1 in both 20%SS:70%LB:10%OFMSW and 20%SS:50%LB:30%OFMSW. Estimations by the modified Gompertz and logistic function were conclusive methane production rate improved by as much a 60% in a trinary mixture over the production rate during mono-digestion of TWAS alone. The results of the various experiments of this thesis therefore suggest that leachate blending can be used as a strategy to improve biogas production in both bioreactor landfills and anaerobic digesters. Also, sewage scum as an energy-rich substrate can be better utilized during co-digestion with other low-energy substrates.

The human Embryonic Stem Cells (hESCs) and human induced Pluripotent Stem Cells (hiPSCs) have offered numerous advantages including but not limited to model diseases, high-throughput drug screening, and regenerative purposes. However, the employment of monolayer cultures has not been sufficient to mimic the in vivo stem cells niche. Thus, three-dimensional suspension cultures have helped us to advance our knowledge and ease the development of the human organs’ counterparts, commonly referred as organoids. Currently, the challenge is the generation of homogenous and reproducible human Pluripotent Stem Cell (hPSC) aggregates, the basic cellular unit to derive organoids. To date, the Ultra-Low Attachment (ULA) 6-well plates have been routinary used for the hPSC aggregates formation, which mainly relies on the inhibition of the Rho-associated kinase (ROCK) pathway resulting in the enhancement of cell survival coming from cryopreserved stocks or when passaging. However, little is known in this regard when analyzing the aggregate formation of hPSCs with two widely used compounds: RevitaCellTM Supplement and Y27632. Importantly, due to the high demand required from the regenerative medicine, I aimed to upscale the hPSC aggregates production in the DASbox® Mini-Bioreactor System. In this thesis, I established protocols for the hPSC aggregates formation by using two different types of media in two platforms being the ULA 6-well plates and the DASbox® Mini-Bioreactor System. In addition, I demonstrated that monolayer confluence cultures before single cell inoculations are paramount for the formation of bona fide hPSC aggregates in healthy and X aneuploid hiPSCs, precisely two hESCs and five hiPSCs.