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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

Tratabilidade de lixiviado de aterro sanitário por reagente de Fenton consorciado com esgoto sanitário em biofiltro aerado submerso / Treatability of landfill leachate by Fenton\'s reagent combined with submerged aerated bioreactor

Fazzio, Araceli Laranjeira 15 April 2014 (has links)
A disposição ambientalmente adequada dos resíduos sólidos em aterros sanitários requer atenção ao tratamento do lixiviado gerado, que atualmente representa um desafio aos engenheiros, técnicos e pesquisadores da área. Esse trabalho avalia a tratabilidade do lixiviado pelo processo oxidativo avançado Reagente de Fenton, seguido por tratamento consorciado com esgoto sanitário em biofiltro aerado submerso. Os ensaios com Reagente de Fenton foram realizados em escala de bancada, com tempo de duração de 70 min por batelada; constatou-se que a razão mássica mais eficiente em termos de remoção de DQO do lixiviado bruto foi de 2:1 (H2O2:Fe II). Os resultados mostraram que esse tratamento reduziu, em média, 62% da DQO do lixiviado bruto. Entretanto, houve acréscimo do teor de sólidos no efluente e formação de lodo. Quanto ao tratamento consorciado com esgoto sanitário, foram utilizados dois biofiltros aerados submersos - reator controle (R1) e reator R2, que recebia 2% de lixiviado tratado por reagente de Fenton - com vazões de 330 mL/h e 450 mL/h, respectivamente, ambos com tempo de detenção hidráulica de 12 h. No período monitorado e considerando as eficiências médias de remoção de DQO de 75% e 70% e de DBO de 95% e 88% nos reatores R1 e R2, respectivamente, não foi possível concluir se houve tratamento do lixiviado ou apenas diluição. Entretanto, foi observado que a adição de lixiviado comprometeu a eficiência de remoção de matéria orgânica na forma de COD, no biofiltro R2. / The environmentally sound disposal of solid waste in landfills requires attention to the treatment of the leachate generated, which currently represents a challenge to the engineers, technicians and researchers. This research assesses the treatability of leachate by advanced oxidation process Fenton\'s reagent, followed by combined treatment with sewage submerged aerated biofilters. Assays with Fenton\'s reagent were performed in a bench scale, with a duration of 70 min per batch, it was found that the most efficient weight ratio in terms of COD removal of crude leachate was 2:1 (H2O2:Fe II). Results shows that treatment decreased on average 62% of the COD of the crude leachate. However, there was an increase of solids in the effluent and sludge formation. As for combination with sewage treatment, two submerged aerated biofilters were used - control reactor (R1) and R2 reactor, which received 2% of treated leachate by Fenton\'s reagent - with flows of 330 mL/h and 450 mL/h, respectively, both with a hydraulic retention time of 12 h. In the monitored period and considering the average COD removal efficiencies of 75% and 70% of BOD and 95% and 88% in the reactors R1 and R2, respectively, it was not possible to conclude whether there was treatment of leachate or just dilution. However, it was observed that the addition of leachate compromised the efficiency of removal of organic material in the form of COD in the biofilter R2.
152

Anaerobic treatment of mine wastewater for the removal of selenate and its co-contaminants / Traitement anaérobie des eaux usées d'origine minière pour l'élimination du séléniate et de ses co-contaminants

Tan, Lea 18 December 2017 (has links)
Cette recherche visait à aborder l’effet des caractéristiques des eaux usées (c’est-à-dire les Co-contaminants, métaux lourds et pH) sur la réduction biologique du Séléniate (SeO42-), et évaluer l'intégration des processus et des configurations pour le traitement des eaux usées chargé de sélénium et de Co-contaminants.La première partie de l’étude portait sur l’effet des accepteurs de Co-électrons et le faible pH sur la bioremédiation du SeO42-, les études expérimentales a montré que le rapport molaire NO3- et SO42- à SeO42- a un facteur de contrôle en augmentant ou en diminuant l'efficacité de l'élimination du sélénium (Se). De plus, l'étude sur les interactions biofilm-Se a révélé la présence de NO3 ou de SO42- influence la spéciation Se, les niveaux de Se (Se0) biogénique et l'activité de la biomasse. Le fonctionnement du réacteur UASB (upflow anaerobic sludge blanket) avec une diminution progressive du pH influent de 7,0 à 5,5 a montré une performance d'élimination stable de NO3-, SO42 et SeO42- ,avant une diminution de 20% de l'élimination de tous ces composants à pH 5,0 En plus, le fonctionnement à long terme du réacteur UASB à pH 5.0 a l'enrichissement des familles Geobacteraceae et Spirochaetaceae, qui n'ont pas été détectés à pH> 5,0.La deuxième partie de l'étude a exploré l'efficacité de différentes techniques d'élimination pour le traitement de SeO42- avec des Co-contaminants. La comparaison des performances d’élimination SeO42- en présence de SO4-2 dans un filtre biotrickling (BTF) et un réacteur UASB a révélé que SO42- a largement influencé la croissance du biofilm attaché et l'élimination de SeO42-a augmentée de> 200%. D'autre part, l'élimination de SeO42- était similaire dans le réacteur UASB indépendamment de la présence ou de l'absence de SO42-. La caractérisation de la biomasse a révélé la formation de Se0 sphérique et de sulfure de poly-sélénium dans la biomasse des deux bioréacteurs. L'addition de Ni dans les deux bioréacteurs a entraîné une diminution des performances de suppression de SO42- et SeO42- de ~ 20-30%. L'élimination du Ni était> 80% dans les deux bioréacteurs. Ni a été éliminé par précipitation sous la forme de sulfure de nickel. L’évaluation du flux de processus pour l'élimination de SeO42- et SO42- a été effectuée en couplant la colonne d'échange d'ions (IX) et le bioréacteur UASB en utilisant soit un prétraitement (IX  UASB), soit un post-traitement (UASB  IX) pour le bioréacteur. Le schéma du processus de prétraitement a montré une meilleure efficacité d'élimination globale de 99% de SO42- et 94% de S totale atteignant <100 mg L-1 de SO42-, <0,3 mg L-1 de Se total et <0,02 mg L-1 de Se dissous dans l'effluent pendant 42 jours de fonctionnement continu / This research aimed at addressing the effect of wastewater characteristics (i.e. co-contaminants, heavy metals and pH) on the biological reduction of selenate (SeO42-) and evaluating process integration and configurations for selenium-laden wastewater treatment with co-contaminants. The first part of the study focused on the effect of co-electron acceptors and low pH on the bioremediation of SeO42-. Experiments showed that the molar ratio of NO3- and SO42- to SeO42- has a controlling factor in either increasing or decreasing the selenium (Se) removal efficiency. Additionally, study on biofilm-Se interactions revealed the presence of either NO3- or SO42- influences the Se speciation, biogenic Se (Se0) levels and biomass activity. Upflow anaerobic sludge blanket (UASB) reactor operation with a gradual decrease in the influent pH from 7.0 to 5.5 showed a stable removal performance of NO3-, SO42- and SeO42-, before a 20% decrease in removal of all these components was observed at pH 5.0. Furthermore, long-term operation of the UASB reactor at pH 5.0 showed the enrichment of Geobacteraceae and Spirochaetaceae families, which were not detected at pH > 5.0.The second part of the study explored the effectiveness of different removal techniques for the treatment of SeO42- with co-contaminants. Comparing the SeO42- removal performance in the presence of SO42- in a biotrickling filter (BTF) and UASB reactor revealed that SO42- largely influenced the attached biofilm growth and increased SeO42- removal by > 200%. On the other hand, SeO42- removal was similar in the UASB reactor irrespective of the presence or absence of SO42-. Biomass characterization revealed the formation of spherical Se0 and poly-selenium sulfide in the biomass of both bioreactors. Addition of Ni in both bioreactors led to a decrease in SO42- and SeO42- removal performance by ~20-30%. Ni removal was > 80% in both bioreactors. Ni was removed via nickel sulfide precipitation. Evaluation of integrated process system for SeO42- and SO42- removal was conducted by coupling an ion exchange column (IX) and UASB bioreactor, using IX as either a pre-treatment (IX  UASB) or post-treatment (UASB  IX) unit for the bioreactor. The pre-treatment process scheme showed a better overall removal efficiency of 99% SO42- and 94% total Se reaching < 100 mg L-1 SO42-, < 0.3 mg Se L-1 total Se and < 0.02 mg Se L-1 dissolved Se in the effluent over 42 days of continuous operation
153

Tratabilidade de lixiviado de aterro sanitário por reagente de Fenton consorciado com esgoto sanitário em biofiltro aerado submerso / Treatability of landfill leachate by Fenton\'s reagent combined with submerged aerated bioreactor

Araceli Laranjeira Fazzio 15 April 2014 (has links)
A disposição ambientalmente adequada dos resíduos sólidos em aterros sanitários requer atenção ao tratamento do lixiviado gerado, que atualmente representa um desafio aos engenheiros, técnicos e pesquisadores da área. Esse trabalho avalia a tratabilidade do lixiviado pelo processo oxidativo avançado Reagente de Fenton, seguido por tratamento consorciado com esgoto sanitário em biofiltro aerado submerso. Os ensaios com Reagente de Fenton foram realizados em escala de bancada, com tempo de duração de 70 min por batelada; constatou-se que a razão mássica mais eficiente em termos de remoção de DQO do lixiviado bruto foi de 2:1 (H2O2:Fe II). Os resultados mostraram que esse tratamento reduziu, em média, 62% da DQO do lixiviado bruto. Entretanto, houve acréscimo do teor de sólidos no efluente e formação de lodo. Quanto ao tratamento consorciado com esgoto sanitário, foram utilizados dois biofiltros aerados submersos - reator controle (R1) e reator R2, que recebia 2% de lixiviado tratado por reagente de Fenton - com vazões de 330 mL/h e 450 mL/h, respectivamente, ambos com tempo de detenção hidráulica de 12 h. No período monitorado e considerando as eficiências médias de remoção de DQO de 75% e 70% e de DBO de 95% e 88% nos reatores R1 e R2, respectivamente, não foi possível concluir se houve tratamento do lixiviado ou apenas diluição. Entretanto, foi observado que a adição de lixiviado comprometeu a eficiência de remoção de matéria orgânica na forma de COD, no biofiltro R2. / The environmentally sound disposal of solid waste in landfills requires attention to the treatment of the leachate generated, which currently represents a challenge to the engineers, technicians and researchers. This research assesses the treatability of leachate by advanced oxidation process Fenton\'s reagent, followed by combined treatment with sewage submerged aerated biofilters. Assays with Fenton\'s reagent were performed in a bench scale, with a duration of 70 min per batch, it was found that the most efficient weight ratio in terms of COD removal of crude leachate was 2:1 (H2O2:Fe II). Results shows that treatment decreased on average 62% of the COD of the crude leachate. However, there was an increase of solids in the effluent and sludge formation. As for combination with sewage treatment, two submerged aerated biofilters were used - control reactor (R1) and R2 reactor, which received 2% of treated leachate by Fenton\'s reagent - with flows of 330 mL/h and 450 mL/h, respectively, both with a hydraulic retention time of 12 h. In the monitored period and considering the average COD removal efficiencies of 75% and 70% of BOD and 95% and 88% in the reactors R1 and R2, respectively, it was not possible to conclude whether there was treatment of leachate or just dilution. However, it was observed that the addition of leachate compromised the efficiency of removal of organic material in the form of COD in the biofilter R2.
154

Using transgenic plants as bioreactors to produce high-valued proteins.

January 2001 (has links)
Cheung Ming-yan. / Thesis submitted in 2000. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 169-185). / Abstracts in English and Chinese. / Thesis committee --- p.i / Statement --- p.ii / Abstract --- p.iii / Acknowledgement --- p.vi / General abbreviations --- p.viii / Abbreviations of chemicals --- p.x / List of figures --- p.xii / List of tables --- p.xv / Table of Contents --- p.xvii / Chapter Chapter 1 --- General Introduction - Using transgenic plants as bioreactor --- p.1 / Chapter 1.1 --- Plant as Bioreactor --- p.1 / Chapter 1.1.1 --- Plant transformation historical milestones --- p.1 / Chapter 1.1.2 --- Applications of transgenic plants --- p.5 / Chapter 1.1.2.1 --- Examples of in situ Application --- p.5 / Chapter 1.1.2.2 --- Examples of ex situ application of transgenic plant --- p.9 / Chapter 1.2 --- Plant Hosts for Transformation: Arabidopsis thaliana and Glycine max --- p.18 / Chapter 1.2.1 --- Essential components for plant transformation --- p.18 / Chapter 1.2.1.1 --- Marker genes --- p.18 / Chapter 1.2.1.2 --- Promoters --- p.18 / Chapter 1.2.2 --- Arabidopsis thaliana --- p.20 / Chapter 1.2.2.1 --- Agrobacterium-mediated transformation --- p.20 / Chapter 1.2.2.2 --- Transformation methods for A. thaliana --- p.21 / Chapter 1.2.3 --- Glycine max (soybean) --- p.22 / Chapter 1.2.3.1 --- Soybean cultivars for transformation --- p.23 / Chapter 1.2.3.2 --- Soybean regeneration systems --- p.24 / Chapter 1.2.3.3 --- Soybean transformation systems --- p.26 / Chapter 1.3 --- Target Pharmaceutical and Agricultural Proteins: Lymphocytic choriomeningitis virus and Goldfish Growth hormones I and II --- p.29 / Chapter 1.3.1 --- Production of pharmaceutical proteins --- p.29 / Chapter 1.3.1.1 --- Lymphocytic choriomeningitis virus --- p.30 / Chapter 1.3.1.2 --- Nucleoprotein of LCMV --- p.33 / Chapter 1.3.2 --- Agricultural protein category --- p.34 / Chapter 1.3.2.1 --- Carassius auratus --- p.34 / Chapter 1.3.2.2 --- Growth hormones I and II --- p.35 / Chapter 1.4 --- Hypothesis and Objectives --- p.37 / Chapter Chapter 2 --- Materials and Methods --- p.38 / Chapter 2.1 --- Materials --- p.38 / Chapter 2.1.1 --- "Plants, bacterial strains and vectors" --- p.38 / Chapter 2.1.2 --- Chemicals and Regents --- p.43 / Chapter 2.1.3 --- Commercial kits --- p.44 / Chapter 2.1.4 --- Primers and Adaptors --- p.45 / Chapter 2.1.5 --- Equipments and Facilities used --- p.47 / Chapter 2.1.6 --- "Buffer, solution and medium" --- p.47 / Chapter 2.2 --- Methods --- p.48 / Chapter 2.2.1 --- Molecular Techniques --- p.48 / Chapter 2.2.1.1 --- Bacterial cultures for recombinant DNA and plant transformation --- p.48 / Chapter 2.2.1.2 --- Recombinant DNA techniques --- p.48 / Chapter 2.2.1.3 --- "Preparation and transformation of DH5a, DE3 and Agrobacterium competent cells" --- p.49 / Chapter 2.2.1.4 --- Gel electrophoresis --- p.52 / Chapter 2.2.1.5 --- "DNA, RNA and protein extractions" --- p.53 / Chapter 2.2.1.6 --- Generation of cRNA probes for Southern and Northern blot analyses --- p.56 / Chapter 2.2.1.7 --- Southern blot analysis --- p.56 / Chapter 2.2.1.8 --- Northern blot analysis --- p.57 / Chapter 2.2.1.9 --- Expression of Lymphocytic choriomeningitis virus nucleoprotein (LCMV NP) in bacterial system --- p.58 / Chapter 2.2.1.10 --- Western blot analysis for LCMV NP --- p.59 / Chapter 2.2.1.11 --- Protein dot blot for detecting the presence of recombinant LCMV-NP generated from transgenic plants --- p.62 / Chapter 2.2.1.12 --- PCR techniques --- p.62 / Chapter 2.2.1.13 --- Sequencing --- p.63 / Chapter 2.2.2 --- Plant tissue culture and transformation --- p.64 / Chapter 2.2.2.1 --- Arabidopsis thaliana --- p.64 / Chapter 2.2.2.2 --- Soybean --- p.65 / Chapter 2.2.3 --- In vitro transcription and translation of target genes in rabbit reticulocyte and wheat germ systems --- p.68 / Chapter 2.2.3.1 --- In vitro transcription of target genes with with Ribomix large scale RNA production systems-T7 and SP6 (Promega) --- p.68 / Chapter 2.2.3.2 --- In vitro translation with rabbit reticulocyte lysate and wheat germ extract --- p.69 / Chapter Chapter 3 --- Results --- p.71 / Chapter 3.1 --- Expression of Lymphocytic choriomeningitis virus nucleoprotein (LCMV NP) and goldfish growth hormones I and II (GHI and GHII) in transgenic Arabidopsis thaliana --- p.71 / Chapter 3.1.1 --- Expression of LCMV-NP in transgenic Arabidopsis thaliana --- p.71 / Chapter 3.1.1.1 --- Cloning of the gene encoding LCMV NP into the binary vector system W104 --- p.71 / Chapter 3.1.1.2 --- Transformation of W104-LCMV-NP into the Agrobacterium GV3101/pMP90 --- p.78 / Chapter 3.1.1.3 --- Transformation of LCMV-NP cDNA into Arabidopsis thaliana --- p.80 / Chapter 3.1.1.4 --- Southern blot and Northern blot analyses of transgenic plant containing the LCMV-NP cDNA --- p.83 / Chapter 3.1.1.5 --- Production of recombinant LCMV-NP protein in DE3 cells --- p.90 / Chapter 3.1.1.6 --- Detection of recombinant LCMV-NP protein in transgenic A.thaliana --- p.98 / Chapter 3.1.2 --- Expression of goldfish growth hormones I and II (GHI and GHII) in transgenic Arabidopsis thaliana --- p.105 / Chapter 3.1.2.1 --- "Screening of homozygous lines of goldfish, Carassius auratus, growth hormones transgenic Arabidopsis thaliana" --- p.105 / Chapter 3.1.2.2 --- Southern blot and Northern blot analyses of transgenic plant containing the LCMV-NP cDNA --- p.109 / Chapter 3.1.2.3 --- Detection of recombinant GHI and GHII from transgenic plant --- p.112 / Chapter 3.2 --- In vitro transcription and translation of target genes in rabbit reticulocyte and wheat germ systems --- p.117 / Chapter 3.2.1 --- Subcloning of target genes in pGEM-3Zf(+) vector --- p.117 / Chapter 3.2.1.1 --- Subcloning of LCMV-NP fragment into pGEM-3Zf(+) vector --- p.117 / Chapter 3.2.1.2 --- Subcloning of goldfish GHI and GHII fragments into pGEM-3Zf(+) vector --- p.120 / Chapter 3.2.2 --- In vitro transcription of target genes with Ribomix large scale RNA production systems-T7 and SP6 --- p.125 / Chapter 3.2.3 --- In vitro translation with rabbit reticulocyte lysate and wheat germ extract systems --- p.128 / Chapter 3.3 --- Establishment of Glycine max regeneration and transformation systems --- p.130 / Chapter 3.3.1 --- The Establishment of soybean regeneration system --- p.130 / Chapter 3.3.2 --- Establishment of soybean transformation system --- p.133 / Chapter 3.3.2.1 --- Definition of transformation efficiency --- p.133 / Chapter 3.3.2.2 --- Effects of plant hosts --- p.136 / Chapter 3.3.2.3 --- Effects of Agrobacterium strains --- p.138 / Chapter 3.3.2.4 --- The application of vacuum infiltration --- p.139 / Chapter 3.3.2.5 --- Effect of kanamycin --- p.140 / Chapter 3.3.2.6 --- Effect of cocultivation duration and light/ dark treatment during germination --- p.141 / Chapter 3.3.2.7 --- Application of the detergent Silwet-77 --- p.142 / Chapter 3.3.3 --- Verification of transformation results by PCR screening --- p.143 / Chapter Chapter 4 --- Discussion --- p.147 / Chapter 4.1 --- "Expression of LCMV-NP, GHI and GHII in A. thaliana" --- p.148 / Chapter 4.2 --- Establishing a soybean transformation system --- p.157 / Chapter 4.2.1 --- Plant hosts and explants --- p.158 / Chapter 4.2.2 --- Regeneration of explants --- p.159 / Chapter 4.2.3 --- Agrobacterium strains --- p.161 / Chapter 4.2.4 --- Bacteria-plant interaction --- p.161 / Chapter 4.2.5 --- Transient versus stable transformation --- p.165 / Chapter 4.3 --- Conclusion and perspective --- p.167 / References --- p.169 / Appendix --- p.186
155

Effects of inoculum density, carbon concentration, and feeding scheme on the growth of transformed roots of Artemisia annua in a modified nutrient mist bioreactor

Towler, Melissa J. 05 May 2005 (has links)
Previous work has shown that despite the lack of oxygen limitation, transformed roots of Artemisia annua had lower biomass productivity in a nutrient mist bioreactor than in a liquid-phase bubble column reactor where the roots demonstrated metabolic signs of oxygen stress. Mathematical modeling suggested that the roots were too sparsely packed to capture mist particles efficiently and to achieve high growth rates. In this study, higher packing fractions were tested, and the growth rate increased significantly. Similarly, higher sucrose concentrations increased the growth rate. Growth kinetics for 2, 4, and 6 days showed an unexpected decrease or stationary growth rate after only 4 days for both 3% and 5% sucrose feeds. Residual media analyses indicated that carbon was not exhausted, nor were other major nutrients including phosphate. Increasing the misting frequency such that the total amount of carbon delivered from a 3% sucrose feed was equivalent to that delivered in a 5% sucrose feed showed that growth was affected by the modified cycle. These studies showed that both the concentration of carbon source and alteration of misting frequency can significantly increase growth rates of hairy roots in mist reactors.
156

A study of novel acidophilic Firmicutes and their potential applications in biohydrometallurgy

Holanda, Roseanne January 2018 (has links)
The application of biotechnologies in the mining sector has intensified over the last 30 years, driven by the increasing demand for metals associated with the rise in energy costs and the awareness for environmentally responsible mining practices. Acidophilic prokaryotes play an important role in biohydrometallurgy, facilitating the solubilisation and recovery of base metals from ores and waste materials. The potential of novel acidophiles of the phylum Firmicutes for applications in biohydrometallurgical processes is examined in this thesis. Eight strains of extremely acidophilic bacteria were studied and shown to belong to the proposed novel genus “Acidibacillus”. These had been isolated previously from several distinct global locations and were shown to be obligately heterotrophic bacteria with potential to carry out tasks critical to biomining such as regenerating ferric iron (by catalysing the dissimilatory oxidation of ferrous iron), generating sulfuric acid (by the oxidation of zero-valent sulfur and tetrathionate; two strains only), and removing potentially inhibitory dissolved organic carbon. These isolates also demonstrated the ability to catalyse the dissimilatory reduction of ferric iron in anaerobic conditions. Results obtained during this study provide the basis for future research to assess their potential roles in microbial consortia applied in the bio-processing of metal ores. A novel obligately anaerobic acidophilic Firmicute (strain I2511) isolated from sediment obtained from an abandoned copper mine, was characterised in terms of its phylogeny and physiology. This isolate formed a separated clade within the Firmicutes, and was considered to represent a novel candidate genus. It also displayed a unique set of physiological traits, distinct from currently validated species of acidophilic Firmicutes. The isolate was an obligate anaerobe that grew via zero-valent sulfur (ZVS) respiration, generating H2S over a wide pH range (1.8 - 5.0), and also catalysed the dissimilatory reduction of ferric iron. Strains of acidophilic sulfatereducing bacteria (aSRB), also Firmicutes, were shown to reduce ZVS at pH as low as 3. These aSRB, together with isolate I2511, populated a novel variant of a low pH sulfidogenic bioreactor. The “hybrid sulfidogenic bioreactor” (HSB) operated using both sulfate and ZVS as electron acceptors, and glycerol as electron donor. The bioreactor successfully remediated and recovered zinc from circum-neutral pH mine-impacted waters with distinct chemical composition collected from two abandoned lead/zinc mines in the U.K. The microbial consortium used in this system proved to be robust, in which the HSB generated H2S consistently under a wide pH range (2 – 7). Experiments demonstrated that H2S could also be generated abiotically in a non-inoculated low pH reactor, by the chemical reaction of ZVS and zero-valent iron to form iron sulfide, and the consequent acid dissolution of the latter. Operational costs and the advantages of biogenic and abiotic generation of H2S for recovery of transition metals from mine waters are discussed.
157

Modelling of novel rotating membrane bioreactor processes

Jones, Franck Anderson January 2017 (has links)
Previous membrane researches undertaken over the years to develop general deadend filtration models made use of an approach that combined all three classical fouling mechanisms, namely, pore blocking, pore constriction and cake filtration. More recently researchers have modified and adapted this modelling approach for a cross flow side-stream membrane bioreactor (MBR) system. Literature also reveals that there have been numerous recent experimental studies conducted on rotating membrane bioreactor (RMBR) systems. Some of these studies have resulted in the creation of RMBR models of the membrane fouling process as well. However, simulation and modelling of the fouling in RMBRs is still a nascent topic to date due to poor understanding and great complexity of the system hydrodynamics involved. Even when models are developed, they are either too complex to be useful at operational level, or not comprehensive enough to express all possible operational scenarios. In many cases they are simply too difficult to calibrate and thus ending up being more suited as research tools rather than for direct process control. As such, further research is required in this area. The research reported in this thesis consists of the development and validation of a RMBR system fouling model that incorporates all three classical fouling mechanisms. This thesis work is divided into two main sections. On top of a literature review that thoroughly describes the background theory and general information on MBRs along with their state of the art, the first section of the thesis also explains the specific methodologies used to accomplish all the main tasks carried out in this research work. The first step of these methodologies involves the setting-up of a rotating MBR system process based upon the FUV-185-A15R Flexidisks membrane module that was developed by Avanti Membrane Technology (USA). This system was used to collect the majority of the data used in this thesis. Since some of these data outputs were compared against non-rotating MBR systems, a similar setting-up process for a bespoke static square MBR system was carried out as well. Using synthetic wastewater in conjunction with activated sludge, mixed liquor suspended solids in both MBR system bioreactors were increased in levels over time to desired levels (i.e. by periodic excess sludge wasting). Trans-membrane pressure (TMP)-stepping fouling data was then acquired from operations of these membrane ultrafiltration processes. This data was obtained by measuring the flux decline or TMP increase. Following data collection, a dynamic fouling model for this RMBR system was then created in Matlab (using the Genetic Algorithm function). To do this, hydrodynamic regimes such as air scouring and rotating shear effects along with all the three classical fouling mechanisms were included in the mathematical fouling model that was created from first principles. For the purpose of comparison, a similar fouling model was created without incorporating the rotational effects for the static square MBR system. This included modelling of the hydrodynamics as well. Finally, both these models were validated and calibrated using the data that were collected from both laboratory-based MBR systems. The second phase of the thesis explores the numerous outputted results produced via model simulations which were then discussed and analysed in great detail. Results from this research indicate that the mathematical models give a decent portrayal and description of the fouling mechanisms occurring within a rotating MBR system. It was found that the rotational mechanisms in terms of fouling prevention accounted for only twelve percent of cake removal with the rest being accomplished through the air scouring mechanism. However, it was found that although the slowly rotating spindle induced a weak crossflow shear, it was still able to even out cake build up across the membrane surface, thus reducing the likelihood of localised critical flux being exceeded, which would lead to dramatic loss of flux. Furthermore, when compared against the static MBR system, the study concluded that a rotating MBR system could increase the flux throughput by a significant amount. In conclusion, RMBR systems appear to represent alternative viable solutions when compared against the traditional static MBR systems that currently dominate the industrial and municipal marketplace. In future, RMBR systems may become the systems of first choice once there is a better understanding of the rotational processes, and once research and design into this sector broadens. Future study areas should thus focus on: whether the forces acting on an activated sludge particle during rotation have a significant effect on the fouling or the shear hydrodynamic regimes; whether activated sludge and benchmark models could be created for rotating MBRs whilst including the shear effects and hydrodynamic regimes; whether model predictive control using these developed RMBR models would enhance efficiency gains within an operational plant; and, whether the real measured soluble microbial products (SMP) concentrations could be used to create an even better SMP predictive model that accurately explains fouling behaviour.
158

Avaliação de diferentes estratégias de biorremediação de solo argiloso contaminado por óleo em biorreator de fase semi-sólida / Assessement of bioremediatioi strategies for treatment of oil contamiatedclay soil in slurry reactors

Maria de Fátima Barbosa de Almeida 28 April 2011 (has links)
A prática da troca de óleo lubrificante usado, particularmente óleos automotivos, representa um grave problema ambiental em função de sua natureza perigosa, do manuseio incorreto e do descarte indiscriminado no meio ambiente. A investigação quanto à remediação de áreas contaminadas por esse resíduo torna-se necessária, particularmente para solo de natureza argilosa. O presente estudo teve por objetivo avaliar a biorremediação de um solo argiloso contaminado por óleo lubrificante utilizando biorreatores de fase semi-sólida. Frascos tipo Erlenmeyer, contendo 20 g de solo contaminado com 3% (m/m) de óleo lubrificante, em triplicata, foram mantidos em temperatura e agitação constantes, segundo as seguintes estratégias de tratamento: (i) Bioestímulo com ajuste de nutrientes (BIOE); (ii) Bioaumento com adição de inóculo microbiano aclimatado (BIOA); (iii) Bioestímulo e adição de surfactante sintético Tween-80 (BIOES); (iv) Bioaumento, bioestímulo e surfactante sintético Tween-80 (BIOAS) e (iv) controle, com água destilada purificada (CONT). A eficiência de remoção do contaminante foi avaliada após 68 dias de tratamento por análises de evolução de CO2, redução de COT, decaimento de HTP, de n-alcanos e frações de hidrocarbonetos saturados, aromáticos e compostos polares. O tratamento BIOAS resultou na maior produção de CO2 acumulada (1247,0 mg.20g-1 de solo) seguida pelo tratamento BIOES (1077,6 mg.20g-1 de solo). Ao final do experimento, todos os tratamentos reduziram significativamente os teores de HTPs quando comparados ao controle (11,14,2%). Os tratamentos BIOAS e BIOES não apresentaram diferenças significativas quanto à redução de HTPs (42,03,7% e 37,46,3%, respectivamente). Tanto o bioestímulo quanto o bioaumento mostraram-se estratégias com potencial para aumentar a eficácia da biorremediação de solos argilosos, sendo que a adição de surfactante foi o fator mais importante, tendo aumentado significativamente a capacidade de remoção em ambas as estratégias. O uso de biorreatores em fase semi-sólida na biorremediação de solo argiloso contaminado com óleo lubrificante mostrou-se bastante promissor e tal estratégia pode ser aplicada em escala imediatamente superior / The practice of exchange of used lubricating oil, automotive oils in particular, represents a serious environmental problem due to its hazardous nature, the misuse and its indiscriminate disposal of same in the environment. Strategies for remediation of contaminated areas by this waste are necessary, particularly in case of soils with clayey nature. This study aimed to evaluate the bioremediation of a clayey soil contaminated by lubricating oil using bioreactors of semi-solid phase. Erlenmeyer flasks containing 20 g of contaminated soil with 3% (w / w) of lubricating oil, in triplicate, were kept at constant temperature and agitation, according to the following treatment strategies: (i) biostimulation with nutrient adjustment (BIOE), (ii) addition of bioaugmentation with microbial inoculum acclimated (BIOA), (iii) addition of biostimulation and synthetic surfactant Tween-80 (BIOES) (iv) bioaugmentation, biostimulation and synthetic surfactant Tween-80 (BIOAS) and (iv) control with purified distilled water (CONT). The contaminant removal efficiency was evaluated after 68 days of treatment by analysis of evolution of CO2, reduction of TOC, decay of HTP, n-alkanes, and fractions of saturated hydrocarbons, aromatics and polar compounds. The BIOAS treatment resulted in increased accumulated production of CO2 (1247.0 mg.20g-1 soil) followed by BIOES treatment (1077.6 mg.20g-1 soil). At the end of the experiment, all treatments significantly reduced the levels of HTP as compared to control (11.1 4.2%). The BIOAS and BIOES treatments presented no significant differences in the reduction of HTP (42.0 3.7% and 37.4 6.3%, respectively). Both biostimulation and bioaugmentation were shown to be strategies with potential to increase the effectiveness of bioremediation in a clayey soil, and the addition of surfactant being the most important factor, increasing significantly the capacity of removal in both strategies. The use of bioreactors in semi-solid phase bioremediation in a clayey soil contaminated by lubricating oil proved to be very promising, and this strategy can be applied to at higher scales
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Avaliação da viabilidade técnica da ampliação de escala da produção de enzimas celulolíticas e hemicelulolíticas por FES em biorreatores de leito empacotado / Evaluation of technical viability of scaling-up the celulolitical and hemicelulolitical enzyme production by SSF in packed bed bioreactors

Perez, Caroline Lopes [UNESP] 03 March 2017 (has links)
Submitted by Caroline Perez (lopesperezcaroline@gmail.com) on 2017-03-15T13:18:05Z No. of bitstreams: 1 Caroline_Lopes_Perez_Dissert_Final.pdf: 6948213 bytes, checksum: 88316394d4ffc78684a65d0a022b2c93 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2017-03-21T14:27:52Z (GMT) No. of bitstreams: 1 perez_cl_me_sjrp.pdf: 6948213 bytes, checksum: 88316394d4ffc78684a65d0a022b2c93 (MD5) / Made available in DSpace on 2017-03-21T14:27:52Z (GMT). No. of bitstreams: 1 perez_cl_me_sjrp.pdf: 6948213 bytes, checksum: 88316394d4ffc78684a65d0a022b2c93 (MD5) Previous issue date: 2017-03-03 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Esta dissertação apresenta um estudo sobre a ampliação de escala de biorreatores de leito empacotado para produção de celulases e hemicelulases por fermentação em estado sólido (FES) empregando o fungo termofílico Myceliophthora thermophila I-1D3b e substrato composto por bagaço de cana de açúcar e farelo de trigo. As etapas de desenvolvimento do projeto consistiram em ensaios em biorreator de diâmetro interno e altura iguais a 7,62 e 10 centímetros, de modo que foram realizados ensaios variando tamanho das partículas de bagaço de cana, densidade bulk do leito, taxas de aeração e modo de distribuição da vazão de ar. Com base nos resultados obtidos, observou-se que partículas de bagaço de tamanho reduzido fornecem bons rendimentos de atividades enzimáticas quando submetidas a altas taxas de aeração em leitos de elevada densidade. Partículas maiores forneceram melhores resultados para leitos de �bulk= 0,395 g/cm3 , bem como a utilização de vazão de ar determinada com base no número de Damköhler modificado igual a 1. Resultados obtidos em ensaios em biorreatores de 0,8 metros, com e sem distribuição de ar, mostraram que inserir ar ao longo do leito é uma estratégia que permite aeração eficiente ao longo do sistema fermentativo, sem que ocorra secagem excessiva do substrato. Atividades relativas de CMCase e xilanase atingiram cerca de 1,2 e 0,7, respectivamente. As etapas finais consistiram em fermentações realizadas em biorreator de diâmetro interno e altura iguais a 20 centímetros. Nessas condições, foram testadas duas formas de distribuição de ar ao longo do leito de quatro módulos fermentativos: utilizando um tubo interno perfurado no módulo central inserindo metade da vazão total, e a outra metade inserida pelo inferior do leito e utilizando um tubo interno central, com quatro orifícios por módulo para espalhamento da vazão. Em termos de produção de celulase, o tubo no módulo central se mostrou a melhor alternativa para o aumento de escala, chegando a apresentar 0,8 de atividades enzimáticas relativas de CMCase, e em termos de atividades relativas de xilanase, a melhor opção foi o tubo interno longitudinal, apresentando valores de 0,55. Diante do exposto, o número de Damköhler modificado é interessante do ponto de vista de aumento de escala, no entanto é preciso ainda entender o mecanismo de atividade respiratória dos microrganismos para que os conceitos possam ser aplicados em sinergia, podendo-se assim esperar bom desempenho do processo em escala industrial. / This work presents a study of scale–up packed bed bioreactors for the production of cellulases and hemicellulases by solid-state fermentation (SSF) using the thermophilic fungus Myceliophthora thermophila I-1D3b and substrate composed by sugar cane bagasse and wheat bran. The development phases of the project consist in tests using bioreactors composed by internal diameter and height equal to 7.62 and 10 centimeters, respectively, so that the assays vary the size of the sugar cane bagasse particles, the bulk density, the airflow rate and how’s distributed along the bed. Based on the results obtained, it was defined that the particles of small size provide good results of enzymatic activity yields when submitted to high aeration rates in high bulk density beds. When testing normal size sugarcane bagasse particles, the best results were obtained for the beds with �bulk= 0,395 g/cm3 as well as airflow rate based on the modified Damköhler number equal to 1. Results obtained in tests in 0,8 meter height bioreactors, with and without airflow distribution, show that inserting air in different bed heights is a strategy to ensure efficient aeration throughout the fermentation system without excessive drying of the substrate. Activities related to CMCase and xylanase reached about 1.2 and 0.7, respectively. The final stages consisted in perform fermentation assays in a bioreactor of internal diameter and height equal to 20 centimeters. Under these conditions, two forms of long-term distribution were tested: using an internal ring to insert half of the total flow, together with the other half inserted in the lower part of the bed and using a central internal pipe with 4 holes per module for airflow distribution. In terms of cellulase production, the internal ring showed a better alternative for scaling-up, reaching a valeu of 0.8 CMCase relative enzymatic activities, and with respect to xylanase relative enzymatic activities, the best option was the central pipe, presenting values of 0,55. On the above, the modified Damköhler number is interesting when it refers to scale-up, although it’s necessary to understand the mechanism of respiratory activity of the microorganisms so that the concepts can be applied in synergy, and it can be expected good process performance in industrial scale. / CNPq: 132957/2016-7
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Anaerobic Treatment of Whey Permeate Using Upflow Sludge Blanket Bioreactors

Hwang, Seokhwan 01 May 1993 (has links)
Whey permeate was anaerobically digested in laboratory scale upflow anaerobic sludge blanket reactors. Nine hydraulic retention times between 5 and 0.2 days were examined with a fixed influent concentration of 10.6 ± 0.2 g COD/L. Chemical oxygen demand removal efficiency ranged from 99.0 to 18.9% and maximum production rate of methane gas was 2.67 L/L/day at a hydraulic loading rate of 12.97 kg COD/m3/day. About 70% of the chemical oxygen demand removed was converted to methane. Both the nonlinear least square method with 95% confidence interval and linear regression were used to evaluate kinetic coefficients. The maximum substrate utilization rate, k, and half saturation coefficient, KL, were determined to be 1.269 ± 0.163 Kg COD/kg VSS/day and 1.000 ± 0.179 kg COD/kg VSS/day. The yield coefficient, Y, and biomass decay rate coefficient, Kd, were also determined to be 0.160 ± 0.012 kg VSS/kg COD and 0.027 ± 0.004 day-1, respectively.

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