To improve water quality of drinking water, the Taiwan Water Supply Corp (TWSC) upgraded three water treatment plants (WTP), changing traditional treatment processes into two advanced membrane processes and one advanced ozonation processes in recent years. Membrane water treatment units of the water treatment plant comprise ultrafiltration (UF) and reverse osmosis (RO). And the advanced ozonation water treatment units comprise pellet softening, post-ozonation and biological activated carbon (BAC) adsorption. This study investigated the formation of disinfection byproducts (DBPs), dissolved organic carbon (DOC) and assimilable organic carbon (AOC) at two advanced water treatment plants (ATP) in Kaohsiung City, Taiwan, by implementing a sampling program. The purposes of this study include¡G(1) The evaluation of treatment efficiency of advanced water treatment plants. (2) Application of powdered activated carbon and membrane bioreactor in removing organic compounds in drinking water. TCM was by far the predominant species in the finished water, the average concentration of DPBs in this study at both plants were 13.97¡Ó4.18£gg/L and 21.49¡Ó10.59£gg/L of THMs for plant A and plant B, respectively. However, levels for DPBs compound are low in both plants and lower than the current national drinking water quality standards 80 £gg / L. But for anther typical DPBs (HAAs compounds), the average concentrations were 17.67¡Ó14.50£gg/L and 33.03¡Ó16.24£gg/L of HAA5 for plant A and plant B, respectively. DCAA and TCAA were the two major species of HAAs found in the two water samples under study. The sums of the two species represented in finished water were about 67% and 83% of HAA5 in A and plant B, respectively. The results showed that HAA5 concentration of all samples could meet current USEPA standards for drinking water quality. Importantly, our work show the advanced treatment processes have good removal on DPBs of treated water. In organic compounds removal, there is high efficiency by using post-ozonation combined with BAC, but low efficiency for membrane process due to the inhibition of electrical charge happened on surface of membrane. This inhibition is caused probably by high hardness and high ion strength in water. We found by combining BAC with membrane filtration process will effectively remove the organic compounds and lower the concentration of AOC for passing the limit value suggested in related researches of the world.

Cyanide is a known toxic chemical, the production of plastics, electroplating, tanning, chemical syntheses, etc. At short-term exposure, cyanide causes rapid breathing, tremors, and long-term exposure to cyanide cause weight loss, thyroid effects, nerve damage and death. Although chemical and physical processes can be employed to degrade cyanide and its related compounds, they are often expensive and complex to operate. A proven alternative to these processes is biological treatment, which typically relies upon the acclimation and enhancement of indigenous microorganisms. Biological degradation of cyanide has often been offered as a potentially inexpensive and environmentally friendly alternative to conventional processes. The aims of first part of study were to evaluate the biodegradability of tetracyanonickelate (TCN) by Klebsiella oxytoca under anaerobic conditions. Results reveal that TCN can be biotransformed to methane by resting cells of K. oxytoca. Results also show that TCN biodegradation was inhibited by the addition of nitrate, nitrite, or ammonia at higher concentrations (5 and 10 mM). Moreover, it was found that the optimum pH for TCN conversion by K. oxytoca was about 7.1. Results from the fermenter experiment show that TCN can be completely degraded within 14 days. K. oxytoca is capable of using TCN as the nitrogen source under anaerobic conditions. TCN could be biotransformed to non-toxic end product (methane) by resting cells of K. oxytoca. Those studies provide us insight into the characteristics of TCN conversion by K. oxytoca under anaerobic conditions. In second part of this study, the technology of immobilized cells can be applied in biological treatment to enhance the efficiency and effectiveness of biodegradation. In this study, potassium cyanide (KCN) was used as the target compound and both alginate (AL) and cellulose triacetate (CT) gels were applied for the preparation of immobilized cells. The free suspension systems reveal that the cell viability was highly affected by initial KCN concentration and pH. Results show that immobilized cell systems could tolerate a higher level of KCN concentration and wider ranges of pH. In the batch experiments, the maximum KCN removal rates using alginate and cellulose triacetate immobilized beads were 0.108 and 0.101 mM h-1 at pH 7, respectively. Results also indicate that immobilized system can support a higher biomass concentration. Complete KCN degradation was observed after the operation of four consecutive degradation experiments with the same batch of immobilized cells. This suggests that the activity of immobilized cells can be maintained and KCN can be used as the nitrogen source throughout KCN degradation experiments. The maximum KCN removal rates using AL and CT immobilized beads in continuous-column system were 0.224 and 0.192 mM h-1 with initial KCN concentration of 3 mM, respectively. In third part of this study, a microbial process for the degradation of propionitrile by K. oxytoca was studied. The free and immobilized cells of K. oxytoca were then examined for their capabilities on degrading propionitrile under various conditions. The efficiency and produced metabolic intermediates and end-products of propionitrile degradation were monitored in bath and continuous bioreactor experiments. Results reveal that up to 100 mM and 150 mM of propionitrile could be removed completely by the free and immobilized cell systems, respectively. Furthermore, AL and CT immobilized cell systems show higher removal efficiencies in wider ranges of temperature (20-40¢XC) and pH (6-8) compared with the free cell system. Results also indicate that immobilized cell system could support a higher cell density to enhance the removal efficiency of propionitrile. Immobilized cells were reused in five consecutive degradation experiments, and up to 99% of propionitrile degradation was observed in each batch test. This suggests that the activity of immobilized cells can be maintained and reused throughout different propionitrile degradation processes. A two-step pathway was observed for the biodegradation of propionitrile. Propionamide was first produced followed by propionic acid and ammonia. Results suggest that nitrile hydratase and amidase were involved in the degradation pathways of K. oxytoca. In the continuous bioreactor, both immobilized cells were capable of removing 150 mM of propionitriles completely within 16 h, and the maximum propionitriles removal rates using AL and CT immobilized beads were 5.04 and 4.98 mM h-1, respectively. Comparing the removal rates obtained from batch experiments with immobilized cells (AL and CT were 1.57 and 2.18 mM h-1 at 150 mM of propionitrile, respectively), the continuous-flow bioreactor show higher potential for practical application. These findings would be helpful in designing a practical system inoculated with K. oxytoca for the treatment of cyanide-containing wastewater.

<p>Analytical analyses conducted at the Himmerfjärden WWTP (285.000 PE connected) identified 70 pharmaceutical compounds belonging to different therapeutic classes. Such organic micropollutants at low detected concentration range of µg - ng l^-1 did not affect the treatment processes at WWTP. Results from analytical studies indicated continuous discharge of organic micropollutants to the surface water with a calculated load amounting to 1.51 kg day-1. Metoprolol, carbamazepine and naproxen were chosen for testing different removal methods. Oxygen Uptake Rate (OUR) tests were conducted to assess the bacterial activity of an activated sludge taken from a full scale aeration plant with the presence of selected target compounds.</p><p>A semi-technical scale membrane bioreactor ZeeWeed10™, treating final effluent from the Himmerfjärden WWTP (Sweden) was seeded with activated sludge from full scale biological stage. The membrane bioreactor (MBR) system placed after the final treatment appeared to be an insufficient technology for removal of residual amounts of organic micropollutants from WWTP effluents. Batch test studies with activated sludge taken from the membrane bioreactor and with application of granular activated carbon (GAC) filtration resulted in giving an overall assessment of removal efficiency. Metoprolol and carbamazepine tend to be resistant to the biodegradation process and in the dosed high concentration lead to bacterial cell decomposition in the activated sludge. Apparently, removal efficiency for naproxen exceeded the value of 46% with the spiked initial amount of 3.3 mg NAP g^-1MLSS. Application of the GAC filtration proved to be an efficient technique for removal of pharmaceutical compounds from treated wastewater.</p><p>Application of the statistical programme Modde7 was a time saving tool in studies of fouling occurrence. The effect of fouling phenomenon, which is a highly limiting factor for MBR performance, was minimised by adjusting the operational parameters as predicted by the Modde7 programme.</p>

Summary Juliane Schneevoigt „Investigation of time- and pressure-dependent expression of different components of the extracellular matrix by chondrocytes in vitro” Institute of Anatomy, Histology and Embryology of the University of Leipzig Submitted in June 2015 98 pages, 34 figures, 41 tables, 153 references keywords: cartilage, chondrocytes, hydrostatic pressure, bioreactor, qPCR Introduction Hyaline cartilage maintains the basic function of transmitting articular pressure load within synovial joints and therefore provides the basis for the movements of an organism. Being a small coverage of the joint surface, it shows a composition designed to match this function specifically. A high amount of proteoglycans and its associated water determines the elastic formability of the hyaline cartilage which allows the absorbance of pressure and shear forces. These proteoglycans, mainly based on aggrecan as core-protein, are embedded into a meshwork of collagen fibres, primarily formed of collagen type II. This composition is not to be understood as a static construct; moreover it is exposed to biophysical forces that permanently require a dynamic adaptation. This adaptation of the extracellular matrix formed by proteoglycans and collagen type II is organised by a small number of embedded chondrocytes, the cells of the hyaline cartilage. As chondrocytes are post-mitotic cells and due to the lack of vascularisation within hyaline cartilage, there is hardly any chance for regeneration of defects in order to maintain the integrity of the tissue. The resulting replacement is formed as fibrocartilage, which has not the capability to withstand the biodynamical forces within the joint. As these defects in hyaline cartilage represent a gross of the diseases of the musculoskeletal system, there is a high medical interest in the development of innovative cell-based therapies, as autologous chondrocyte transplantation (ACT) is one. With this type of therapy in vitro cultivated chondrocytes are seeded into a cartilage defect with the aim of producing hyaline cartilage. Aims of the study In the last decades the need for a detailed understanding of the biodynamics of cartilage became obvious for further development of therapies. The aim of this study was therefore to establish a cell culture system to provide an insight into the biodynamics of chondrocytes. Aside from the examination of the differentiation of in vitro cultivated chondrocytes and their synthesis of extracellular matrix as a function of the cultivation time, another aim of this study was to determine whether the application of hydrostatic pressure might have beneficial influence on the expression of extracellular matrix components by chondrocytes in vitro, in accordance with the hyaline cartilage. Material and methods Human articular chondrocytes were cultivated in vitro without the application of hydrostatic pressure in the first place. The cells were observed phase contrast microscopically and the distribution of collagen type I and II was detected immuncytochemically. In further experiments optical confluent chondrocytes were transferred to a bioreactor system applying a hydrostatic pressure of 5 or 10 bar with variable time periods of the pressure applied. Subsequently, the expression of collagen type I, collagen type II and aggrecan was investigated and quantified using qPCR and Western Blot. Chondrocytes cultivated exclusively without the application of hydrostatic pressure served as controls. In this pilot-study the samples were analysed using arithmetic mean and standard deviation to evaluate the power statistically. In addition, similar test conditions with marginal differences were pooled and the necessary sample size to meet a power of 80 % with an alpha error of 0.05 was calculated using the maximum potential standard deviation. In cases where this statistic power was obtained, an analysis of significance (\"One Way Analysis of Variance”) was carried out meeting a significance level under 0.05. Results During the cultivation of chondrocytes in vitro without hydrostatic pressure the length of the cultivation time did neither show an effect on the phase contrast microscopical morphology nor on the immuncytochemically detected distribution of collagen typ I and II. The application of increased hydrostatic pressure for 24 hours results in a 0.2-0.8-fold decrease of the expression of collagen type I and II and a 1.7-2.2-fold increase of aggrecan expression compared to the unloaded controls. This effect was more distinct with 5 bar but was accompanied by instabilities in the cell culture. This is why further investigations concentrated on the use of 10 bar pressure with subsequently shortened time period of the applied pressure. With short times of loading (1.5 and 3 hours) a pressure load of 10 bar led to a 0.8 fold decrease of the expression of collagen type I and II and showed a 1.6-2.4 fold increase of aggrecan expression. These qPCR results were supported by the protein expression of collagen type I, II and aggrecan detected in Western Blot. Conclusions A cell culture system was established to examine the effect of hydrostatic pressure on the expression of chondrocytes on the one hand, which can further be modified for the assembly of cell transplants on the other hand. Subsequently the results of this study led to a definition of cell culture conditions, stimulating the extracellular matrix production of chondrocytes towards the composition of hyaline cartilage. This was the case using a seeding density of 104 cells/cm2 and a pre-cultivation time of 6 days of normal pressure, followed by the application of 10 bar hydrostatic pressure for 1.5-3 h. With the help of this pilot-study a cell culture system was established to gain more information on biodynamics of hyaline cartilage. Moreover it is possible that this information will provide a basis for further development of cell based therapies of cartilage defects, such as ACT. / Zusammenfassung Juliane Schneevoigt „Untersuchung der zeit- und druckabhängigen Expression verschiedener Komponenten der extrazellulären Matrix durch Chondrozyten in vitro“ Veterinär-Anatomisches Institut der Veterinärmedizinischen Fakultät der Universität Leipzig Eingereicht im Juni 2015 98 Seiten, 34 Abbildungen, 41 Tabellen, 153 Literaturangaben Schlüsselwörter: Knorpel, Chondrozyten, hydrostatischer Druck, Bioreaktor, qPCR Einleitung Der hyaline Knorpel gewährleistet die grundlegende Funktion der Druckübertragung innerhalb der synovialen Gelenke und stellt somit die Grundlage für die Bewegung des Organismus dar. Als schmaler Überzug der Gelenkflächen ist er in seinem Aufbau an diese Funktion spezifisch angepasst. Dabei bedingt der hohe Gehalt an Proteoglykanen und das an diese assoziierte Wasser die elastische Verformbarkeit des hyalinen Knorpels, die es ermöglicht, Druck- und Scherkräfte abzufedern. Die Proteoglykane, die hauptsächlich auf Aggrekan als Kernprotein basieren, sind in ein Maschenwerk kollagener Fasern eingelagert, welches im Wesentlichen durch Kollagen Typ II gebildet wird. Diese Zusammensetzung darf nicht als statisches Konstrukt verstanden werden. Vielmehr ist der hyaline Knorpel in vivo verschiedenen biophysikalischen Einflüssen ausgesetzt, die eine dynamische Anpassung erfordern. Solche Anpassungsvorgänge in Form einer Änderung der Zusammensetzung der aus kollagenen Fasern und Proteoglykanen bestehenden extrazellulären Matrix werden durch die wenigen eingelagerten Chondrozyten, die Zellen des hyalinen Knorpels, organisiert. Da die reifen Chondrozyten jedoch keine Zellteilungen aufweisen und dem hyalinen Knorpel eine Vaskularisierung fehlt, ist eine Defektregeneration kaum möglich, sodass eine Wiederherstellung der Integrität des Gewebes unterbleibt und stattdessen ein Ersatzknorpel, der Faserknorpel, gebildet wird, welcher den einwirkenden biodynamischen Belastungen jedoch nicht standhalten kann. Da die Defekte des hyalinen Knorpels einen Großteil der Erkrankungen des Bewegungsapparats darstellen und zudem die Arthrose als Langzeitfolge nach sich ziehen, besteht ein hohes medizinisches Interesse an der Entwicklung zellbasierter Therapieansätze, wie der Autologen Chondrozytentransplantation (ACT). Hierbei werden - bislang mit unterschiedlichen Erfolgen – in vitro kultivierte Chondrozyten mit dem Ziel, neuen hyalinen Knorpel zu bilden, in einen Knorpeldefekt eingebracht. Ziele der Untersuchungen In den letzten Jahrzehnten zeigte sich, dass die Entwicklung von Therapieansätzen zur Behandlung von Knorpeldefekten ein detaillierteres Verständnis des Knorpelgewebes und speziell dessen Biodynamik erfordert. Ziel dieser Arbeit war es daher, im Rahmen einer Pilotstudie, ein In-vitro-System zu etablieren, welches die Untersuchung der Biodynamik der Chondrozyten ermöglicht. Neben der Untersuchung der Morphologie der Chondrozyten und der durch sie synthetisierten extrazellulären Matrix in Abhängigkeit von der Kultivierungszeit der Zellen, wurde die Fragestellung bearbeitet, ob durch die Wirkung eines hydrostatischen Drucks günstige Effekte in Hinblick auf die Expression einer extrazellulären Matrix, wie sie im hyalinen Knorpel vorliegt, erzielt werden kann. Materialien und Methoden Eine Primärkultur humaner artikulärer Chondrozyten wurde zunächst unter Standardzellkulturbedingungen und atmosphärischem Druck kultiviert. Die Zellen wurden phasenkontrastmikroskopisch und hinsichtlich der Verteilung von Kollagen Typ I und II immunzytochemisch untersucht. In den weiteren Versuchen wurden optisch konfluente Chondrozyten in einen Bioreaktor überführt und weiter unter einem hydrostatischen Druck von 5 oder 10 bar kultiviert. Dabei wurde die Dauer der Druckeinwirkung auf die Chondrozyten variiert. Das Expressionsmuster der so kultivierten Chondrozyten wurde quantitativ in Hinblick auf Kollagen Typ I und II sowie Aggrekan mittels qPCR und Western Blot untersucht. Dabei dienten jeweils Chondrozyten, die ohne erhöhte Druckbedingungen kultiviert wurden, als Kontrollen. In dieser Pilotstudie wurden die Proben unter Berechnung der Mittelwerte und Standardabweichung hinsichtlich ihrer statistischen Power ausgewertet. Neben dieser Analyse der Einzelergebnisse wurden die Versuchsbedingungen, die kaum Unterschiede in den Ergebnissen aufwiesen, in Gruppen zusammengefasst und mit Hilfe der größtmöglichen vorhandenen Standardabweichung der Stichprobenumfang eines Versuchs errechnet, welcher die statistische Power der Ergebnisse bei einem Alpha-Fehler von 0,05 auf 80% erhöht. In den Fällen, in denen diese Power erreicht wurde, erfolgte eine Untersuchung der Unterschiede auf Signifikanz („One Way Analysis of Variance“) bei einem Signifikanzniveau < 0,05. Ergebnisse Während der In-vitro-Kultivierung der Chondrozyten unter atmosphärischem Druck zeigte die Länge der Kultivierungszeit weder einen Einfluss auf die phasenkontrastmikroskopisch untersuchte Morphologie der Zellen noch auf die immunzytochemisch detektierte Verteilung des Kollagen Typ I und II. Die Wirkung eines erhöhten hydrostatischen Drucks (5 bar, 10 bar) für 24 Stunden führte zu einer Abnahme der Expression von Kollagen Typ I und Typ II auf das 0,2-0,8-fache bei gleichzeitiger Zunahme der Expression des Aggrekan auf das 1,7-2,2-fache, verglichen mit der unbehandelten Kontrolle. Dieser Effekt war bei 5 bar ausgeprägter als bei 10 bar, führte jedoch gleichzeitig zu einer starken Instabilität des Zellkultursystems. Vor diesem Hintergrund wurde für den höheren Druck (10 bar) die Zeitdauer der Druckeinwirkung verkürzt. Hierbei konnten bei kurzzeitiger Druckeinwirkung von 10 bar (1,5 und 3 Stunden) bei Erhalt der Zellen ähnliche Effekte erzielt werden wie für die Bedingung 5 bar, 24 Stunden. Die Expression von Kollagen Typ I und Typ II sank auf das 0,8-fache, wohingegen ein Anstieg der Aggrekanexpression auf das 1,6-2,4-fache erreicht wurde. Diese Ergebnisse der qPCR konnten durch die im Western Blot für Kollagen Typ I, II und Aggrekan detektierte Proteinexpression gestützt werden. Schlussfolgerungen Im Rahmen dieser Arbeit wurde ein In-vitro-System etabliert, welches einerseits der Untersuchung des Einflusses von hydrostatischem Druck auf die Expression von Chondrozyten dienen und andererseits für die Herstellung von Zelltransplantaten weiter modifiziert werden kann. Die Ergebnisse der Untersuchungen führten zur Definition von Bedingungen für das In-vitro-System, unter denen die Expression der extrazellulären Matrix durch die Chondrozyten in Richtung der Zusammensetzung im hyalinen Knorpel stimuliert werden kann. Dies zeigte sich bei einer Aussaat der humanen Chondrozyten in einer Konzentration von 104 Zellen/cm2 und einer Vorkultivierungszeit von 6 Tagen unter Normaldruck, gefolgt von der Kultivierung unter hydrostatischem Druck von 10 bar für 1,5 bis 3 Stunden. Mit Hilfe dieser Pilotstudie wurde somit ein In-vitro-System etabliert, auf dessen Basis Untersuchungen durchgeführt werden können, die weiterführende Erkenntnisse zur Biodynamik des hyalinen Knorpels liefern und der zukünftigen Entwicklung zellbasierter Therapieansätze der Knorpeldefekte, wie der ACT, zu Gute kommen.

Human mesenchymal stem cells (hMSCs) are a promising candidate for cell-based therapies given their therapeutic potential and propensity to grow in vitro. However, to generate the cell numbers required for such applications, robust, reproducible and scalable manufacturing methods need to be developed. To address this challenge, the expansion of hMSCs in a microcarrier-based bioreactor system was investigated. Initial studies performed in T-flask monolayer cultures investigated the effect of key bioprocess parameters such as dissolved oxygen concentration (dO2), the level of medium exchange and the use of serum-free media. 20 % dO2 adversely impacted cell proliferation in comparison to 100 % dO2, whilst FBS-supplemented DMEM was found to be the most consistent and cost-effective cell culture medium despite the advances in serum-free cell culture media. Several microcarriers were screened in 100 mL agitated spinner flasks where Plastic P102-L was selected as the optimal microcarrier for hMSC expansion given the high cell yields obtained, its xeno-free composition and effective harvest capacity. The findings from the initial small-scale studies culminated in the successful expansion of hMSCs on Plastic P102-L microcarriers in a fully equipped 5 L stirred-tank bioreactor (2.5 L working volume), the largest reported volume for hMSC microcarrier culture to date. A maximum cell density of 1.68 x 105 cells/mL was obtained after 9 days in culture; further growth was limited by the low glucose concentration and lack of available surface area. A novel, scalable harvesting method was also developed, allowing for the successful recovery of hMSCs. Importantly, harvested hMSCs retained their immunophenotype, multipotency and ability to proliferate on tissue culture plastic.

Optical coherence tomography (OCT) is a technology that enables 2D cross-sectional images of tissue microstructure. This interferometric technique provides resolutions of approximately 10-20 um with a penetration depth of 1-2 mm in highly scattering tissues. With the use of fiber optics, OCT systems have been developed for intravascular imaging with a demonstrated improvement in both resolution and dynamic range compared to commercial intravascular ultrasound systems. OCT studies of normal, atherosclerotic, and stented arteries indicate the ability of OCT to visualize arterial structures. These results suggest OCT may be a valuable tool for studying luminal structures in tissue engineered constructs.In the present study, new endoscopic OCT systems and analysis techniques were developed to visualize the growth and response of the cellular lining within a tissue engineered blood vessel mimic (BVM). The BVM consists of two primary components. A biocompatible polymeric scaffold is used to form the tubular structure. Human microvessel cells from adipose tissue are sodded on to the inner surface of the scaffold. These constructs are then developed and imaged within a sterile bioreactor.Three specific aims were defined for the present study. First, an OCT longitudinal scanning endoscope was developed. With this endoscope, a study of 16 BVMs was performed comparing images from OCT and corresponding histological sections. The study demonstrated that endoscopic imaging did not visually damage the mimic cellular lining. OCT images showed excellent correlation with corresponding histologicalsections. Second, a concentric three element endoscope was developed to provide radial cross-sections of the BVM. OCT images using this endoscope monitored lining development on three types of polymeric scaffolds. In the third specific aim, automated algorithms were developed to assess the percent cellular coverage of a stent using volumetric OCT images.The results of the present study suggest that OCT endoscopic systems may be a valuable tool for assessing and optimizing the development of tissue engineered constructs. Conversely, the BVMs modeled the arterial response to deployed stents allowing the development of automated OCT analysis software. These results suggest that blood vessel mimics may be used to advance OCT technology and techniques.

The use of staged scouring aeration to reduce energy for membrane fouling was studied using one pilot-scale submerged membrane bioreactor to treat municipal wastewater. The experiments were conducted by varying each of permeate fluxes, scouring air scouring intensities and sequence during both permeation and relaxation periods while keeping other factors same. The critical and recoverable fluxes were measured by the stepwise flux method. Mixed liquor, permeate and filtrate was characterized by analysing COD, cTOC, SMP contents, etc. The recorded transmembrane pressure data were used to calculate the fouling resistance after relaxation and fouling rate of each cycle. The results showed that when operated at relatively high permeate flux rate, membrane fouling could be effectively controlled by using relatively lower air scouring intensity and/or less infrequent aeration sequence during the permeation combined subsequently with more vigorous and frequent air scouring during the relaxation. At lower permeate flux rate with good permeability sludge, membrane fouling was effectively controlled by relatively low air scouring intensity and/or relatively infrequent aeration sequence during both permeation and relaxation periods. For each sludge condition, an optimal combination of cyclic air scouring intensity and sequence existed which could minimize the aeration energy consumption while maintaining effective fouling control. The frequency of aeration sequence plays a more dominant role than the air scouring intensity during the permeation in aeration optimization. / GE Water & Process Technologies Natural Sciences and Engineering Research Council of Canada

A fuzzy logic controller (FLC) for the dissolved oxygen (DO) concentration of a wastewater bioreactor is presented. The FLC is developed and tested based on simulations using first order plus dead time models obtained from experiments with an actual wastewater bioreactor. The FLC uses feedback of the error in DO concentration and rate of change of the DO concentration and manipulates the stem position of the flow control valves (FCVs) supplying air to the bioreactor. The proposed FLC is tested for robustness across several process models, two of which include proposed worst-case process conditions. The performance of the proposed hand tuned FLC is compared to that of a similarly tuned proportional-integral-derivative controller. The FLC is implemented as a lookup table for speed and ease of deployment. The disturbances present in the experimental step testing data are characterized and used as the basis for disturbing the control loop during controller performance testing. A low-pass filter is then included to subsequently smooth the feedback signal. The nonlinear relationship between the FCV stem position and output flow is modelled and included in the controller performance testing. A genetic algorithm (GA) is developed that manipulates the membership functions of the FLC to yield an optimal controller for the ensemble of process models. The ability of the GA to converge on an optimal FLC is verified through repeated trials. The performance of the GA optimized FLC is observed under realistic process conditions and is benchmarked against a manually optimized PID controller.

Wastewater contains many valuable constituents, including phosphorus, nitrogen and more energy than what is required to treat it. This, combined with increasingly more stringent effluent requirements and the desire for water reuse, creates a demand for a system capable of both nutrient and energy recovery. The main objective was to develop a new wastewater treatment process configuration capable of maximizing energy recovery while enhancing biological phosphorus removal. Three pilot membrane bioreactors were operated at SRTs ranging from 2 days to 8 days to evaluate membrane fouling, treatment performance, sludge production and sludge settleability. The results showed high organics removal and near complete nitrification at all SRTs. Membrane fouling was highest at lower SRTs. The collected data were then used to calibrate a series of model configurations. The best configuration consisted of two sludge systems in series, with a short SRT anaerobic-aerobic first stage and an extended SRT pre-anoxic second stage. / Canadian Water Network

Biphasic systems such as two-phase partitioning bioreactors (TPPBs) have been used to alleviate biological inhibition by sequestering inhibitory compounds within an immiscible phase. The use of solid polymer beads as this auxiliary phase provides a fully biocompatible alternative to commonly used yet potentially toxic organic solvents. This work focused on the application of solid-liquid TPPBs to the bioproduction of the pharmaceutical precursor L-phenylacetylcarbinol (PAC), a biotransformation which suffers from substrate (benzaldehyde), product (PAC), and by-product (benzyl alcohol) inhibition, and simple strategies to improve TPPB performance in general. A wide range of commercially available, biocompatible, and non-bioavailable polymers were screened for their affinity for benzaldehyde, PAC, and benzyl alcohol. Hytrel G3548L demonstrated the highest affinity for all three target compounds and was subsequently used in solid-liquid TPPBs for PAC production. Using 15% v/v polymer beads, PAC concentration was increased by 104% and benzyl alcohol concentration decreased by 38% over the single phase control. The delivery of benzaldehyde from polymer beads demonstrated only a 6-8% reduction in mass productivity with improved operational simplicity and reduced operator intervention. The final objective of this work was to independently investigate various aspects of the aqueous phase composition and determine how each factor affects the partition coefficient of benzaldehyde in Hytrel G3548L. Temperature and pH were observed to have no significant effect on partitioning. Salt and glucose additions increased the partition coefficient by 173% and 30% respectively compared to RO water, while ethanol was found to decrease the partition coefficient from 44 (±1.6) to 1 (±0.3). These findings may be applied to solid-liquid TPPBs to increase or decrease partitioning as required, leading to improved bioreactor performance. This work has successfully shown that with careful polymer selection, solid-liquid TPPBs can be used to increase the productivity of a biotransformation without the associated biocompatibility problems that have sometimes been observed with organic solvents. The delivery of inhibitory substrate from the polymer phase was successfully accomplished, which is a novel demonstration in the field of solid-liquid TPPBs for biocatalysis. Finally this work contributes a range of simple strategies to improve the partitioning behavior of solid-liquid TPPBs using the aqueous phase composition. / Thesis (Master, Chemical Engineering) -- Queen's University, 2010-08-26 10:53:38.569