Tesi: "Extracellular polymeric.substances"

1

Ren, Baisha. "Understanding Extracellular Polymeric Substances in Nitrifying Moving Bed Biofilm Reactor". Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32879.

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Water and wastewater treatment solutions incorporating biofilm systems are becoming increasingly popular due to more stringent regulations pertaining to drinking water and wastewater effluent discharge in Canada and in other parts of the world. As a major component of biofilm, extracellular polymeric substances (EPS) have been considered as an important factor affecting the physical and chemical properties of biofilm. Further, the selected method of EPS extraction and the methods of detecting the composition of the EPS have shown to affect the results of EPS measurements. In this research, protocols for EPS extraction and EPS composition analysis were investigated and optimized for nitrifying moving bed biofilm reactor (MBBR) biofilm. In addition, the confocal Raman microscopy (CRM) spectra of EPS in nitrifying MBBR biofilm and the protein, polysaccharide and extracellular DNA (eDNA) percent concentrations of the EPS were investigated at various operating temperatures. Further, the CRM spectra and the protein, polysaccharide and eDNA percent concentration of EPS in nitrifying MBBR biofilm along with the biofilm morphology and thickness and the viability of the embedded cells were investigated at various hydraulic retention times (HRTs). The EPS was characterized at various temperatures and HRTs in order to investigate potential correlation between the EPS components of the nitrifying biofilm and the ammonia removal kinetics. The biofilm morphology and thickness along with the bacterial viability of the biofilm were also investigated at various HRTs. Biofilm morphology images and thickness measurements were acquired using a variable pressure scanning electron microscope (VPSEM). The percentages of viable embedded cells in the biofilm were quantified using live/dead staining in combination with confocal laser microscopy (CLSM) imaging. The research demonstrates that an increase in protein content and subsequently a decrease in polysaccharides and eDNA contents in the EPS of nitrifying MBBR biofilm were observed at the lowest operational HRT and the highest temperature in this work. In particular, the EPS protein to polysaccharide (PN/PS) ratio of nitrifying MBBR systems was shown to significantly decrease below a value of 3 when the system was underloaded (observed at the highest operational temperature in this study) or hydraulically overloaded (observed at the lowest HRT in this study). As such, data obtained at lower operational temperatures, with the system no longer underloaded, and at longer HRTs, with the system no longer hydraulically overloaded, all demonstrate an EPS PN/PS ratio of approximately 3. Correlations were observed between the chemically measured EPS PN/PS ratios and the measured Raman spectra intensity ratios; supporting the concept of higher PN/PS ratios of EPS in more optimal nitrifying MBBR operations. Further, the ammonia removal kinetics and EPS response at HRT values of 0.75 and 1.0 h indicate that nitrifying MBBR systems may be optimized to operate at HRTs as low as 0.75 to 1.0 hour as opposed to conventional HRTs of 2.0 to 6.0 h.

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2

Lubarsky, Helen V. "The impact of microbial extracellular polymeric substances on sediment stability". Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2099.

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The main objective of this thesis is to investigate the impact of microbial extracellular polymeric substances (EPS) on sediment stability and the related factors which influence “biogenic stabilisation” as a basis to the prediction of sediment erosion and transport. The ability to make direct and sensitive measurements of the physical properties of the biofilm is a critical demand to further understanding of the overall biostabilisation processes. Therefore, attention has been focused on developing a new technique, Magnetic Particle Induction (MagPI) for measuring the adhesive properties of the biofilm. MagPI determines the relative adhesive properties or “stickiness” of the test surface, whether a biofilm, a sediment or other submerged material. The technique may have future applications in physical, environmental and biomedical research. Newly developed Magnetic Particle Induction(MagPI) and traditional techniques Cohesive Strength Meter (CSM) for the determination of the adhesion/cohesion of the substratum were used to assess the biostabilisation capacity of aquatic microorganisms. Whilst these devices determine slightly different surface properties of the bed, they were found to complement each other, increasing the range of measurements that could be made and presented a strong correlation in the overlapping portion of the data. It is recognized that microorganisms inhabiting natural sediments significantly mediate the erosive response of the bed (“ecosystem engineers”) through the secretion of naturally adhesive organic material (EPS: extracellular polymeric substances). Interactions between main biofilm consortia microalgae, cyanobacteria and bacteria in terms of their individual contribution to the EPS pool and their relative functional contribution to substratum stabilisation were investigated. The overall stabilisation potential of the various assemblages was impressive, as compared to controls. The substratum stabilisation by estuarine microbial assemblages was due to the secreted EPS matrix, and both EPS quality (carbohydrates and proteins) and quantity (concentration) were important in determining stabilisation. Stabilisation was significantly higher for the bacterial assemblages than for axenic microalgal assemblages. The peak of engineering effect was significantly greater in the mixed assemblage as compared to the bacterial and axenic diatom culture. This work confirmed the important role of heterotrophic bacteria in “biostabilisation” and highlighted the interactions between autotrophic and heterotrophic biofilm components of the consortia. An additional approach, to investigate the impact of toxins on biostabilisation capacity of aquatic organism was performed on cultured bacterial and natural freshwater biofilm. The data suggest a different mode of triclosan (TCS) action ranging from suppressing metabolisms to bactericidal effects depending on the TCS concentration. The inhibitory effect of triclosanon bacterial and freshwater biofilms was confirmed. This information contributes to the conceptual understanding of the microbial sediment engineering that represents an important ecosystem function and service in aquatic habitats.

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3

Akbar, Sirwan. "Gram negative bacterial biofilm formation and characterisation of extracellular polymeric substances". Thesis, University of Huddersfield, 2016. http://eprints.hud.ac.uk/id/eprint/30236/.

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Abstract (sommario):

Gram negative bacteria such as Stenotrophomonas maltophilia, Pseudomonas aeruginosa and Citrobacter freundii are often associated with multiple drug resistance and the generation of nosocomial infections. In the current study several clinical strains of theses bacteria (Ps 1, Ps 3, Ps 5, St 18, St 51, St 53 and C. freundii) and two culture collection strains Ps 10421 and St 9203 were evaluated for their ability to generate biofilms and the characteristics of the associated extracellular polysaccharides they produced. The ability of these strains to develop biofilms on a range of media and with a number of carbon sources was investigated. A range of mineral media employing glucose, ethanol and glycerol were developed in such a way as to ensure they did not contain compounds that interfere with extracellular polysaccharide analysis allowing a more in depth analysis of the extracellular polysaccharide generated by the bacteria under investigation. Following an assessment of the biofilm forming potential of all the strains under consideration, three were singled out for particular attention, i.e. Ps 3, St 53 and C. freundii strain isolated during this investigation. Two of strains were chosen for the strength of their biofilm forming potential (Ps 3 and St 53), on the other hand C. freundii was chosen because the scientific literature contains very little published information regarding its extracellular polysaccharide and its biofilm forming characteristics. These bacteria were able to produce biofilm on both hydrophobic (plastic) and hydrophilic (glass) surfaces. In order to get a broader understanding of the biofilm forming capabilities of these bacteria their whole genomes were sequenced and subsequently published. These genomes demonstrated that St 53 and C. freundii both contained the pgaABCD which is known to be associated with biofilm formation. Whilst Ps 3 contains a full complement of pel (PA3058-PA3064), psl (PA2231-2245) and alginate biosynthesis operons (PA3540-3548) related to biofilm formation. In addition all three species contained genes associated with virulence, pathogenicity and antibiotic resistance. The generation and extraction of extracellular polymeric substance generated by these three bacteria underwent a period of optimisations which included an optimisation of both the media and the growth conditions and the extraction process. In particular the use of trichloroacetic acid (TCA) was found to be critical with 0-5% TCA considered optimum for the removal of proteins prior to polysaccharide extraction. This is far less than has been previously employed in studies on lactic acid bacteria, however when used with the Gram negative bacteria investigated here, high levels of TCA degraded the polysaccharide that was being generated preventing its extraction in the quantities required for analysis. Analysis of the polysaccharides produced by St 53, Ps 3, and C. freundii, all demonstrated typical NMR spectra associated with bacterial extracellular polysaccharide. However, the NMR spectra from these polysaccharides also contained peaks typical of the presence of dextran. The use of a fungal dextranase confirmed the presence of a dextran like polymer in the polysaccharide generated by these bacteria. This indicated that all three of these bacteria generated complex polysaccharides with at least two components one mannose rich and the second a dextran like glucose rich polymer. This is the first report of a dextran being associated with the EPS of these bacteria and suggests that the Pel polysaccharide of P. aeruginosa is a dextran. Investigation of bacterial pathogenicity focussed on Ps 3 since P. aeruginosa is the most pathogenic of the three species investigated. The culture collection strain Ps 10421 failed to produce outer membrane vesicles (OMV) without antibiotic treatment, however Ps 3 generated OMV under normal growth conditions generating more when grown on ethanol rather than glucose. In order to investigate the impact of ethanol vs glucose grown culture a wax worm pathogenicity model was employed. This model revealed that ethanol grown cells were more pathogenic than glucose grown cells. This difference could be attributed to the effects of type of carbon sources that induce virulence genes to generate more toxins. Transcriptomic analysis of Ps 3 grown with ethanol vs growth on glucose revealed large differences in gene expression but no definitive evidence of which cellular processes were responsible for this enhanced pathogenicity associated with grown on ethanol.

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4

Pen, Yu. "Conformational and mechanical properties of bacterial mycolic acid and extracellular polymeric substances". Thesis, University of Sheffield, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566700.

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Rhodococcus has been used in bioremediation because of its low eco- toxicity, high tolerance to harsh environments, and ability to be cultivated in mixed microbial consortia with certain contaminants as its nutrients. Excretion of extracellular polymeric substances (EPS) allows Rhodococcus to trap and to effectively degrade contaminants. Mycolic acid (MA) which covers the cell wall provides Rhodococcus with a hydrophobic cell surface to contact hydrocarbon contaminant droplets. This work concerns the influence of the conformational change in MA and rhodococcal EPS on their mechanical properties. Neutron reflection revealed that when the solution pH increases, a hydration layer is generated between the bound (hydrophobic) MA (LB _MA) and the silicon substrate, whereas the intermolecular repulsion unfolds the extractable (hydrophilic) MA (LS_MA), and allows water to fill in the formerly folded space. Force spectroscopy using a polystyrene colloidal probe showed that the strength of the adhesion force between a hydrophobic particle and MA is affected by the conformation of MA. The existence of a hydration layer in the MA enhances cell adhesion. Classical DLVO theory indicated that the electrostatic force dominates the long range (a distance larger than the Debye length) interactions between a polystyrene (hydrophobic) particle and MA, whereas the van der Waals force has a negligible influence. EPS generated at the early exponential phase (E EPS) and the late stationary phase (S EPS) of Rhodococcus manifested different physiochemical and mechanical properties. Force spectroscopy using Rhodococcus as a bacterial cell probe suggested that S EPS possess a higher differential capacitance than E EPS do for cells to store charges and energy. The nonspecific binding sites to silicon (an abundant material in the sediments of groundwater) are not evenly distributed; they exist mainly in S EPS close to the cell surface, but rarely in E EPS. Therefore, S EPS have a stronger adhesion to the silicon surface than E EPS do. Contraction and stretch of the EPS chains affect the strength of the adhesion force to a silicon surface. S EPS possess a better resilience against compression than E EPS do, thus retaining water in both S EPS and the inner E EPS. 4

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5

Rode, Alexander. "Isolierung und Charakterisierung von bakteriellen extrazellulären polymeren Substanzen aus Biofilmen / Isolation and characterization of bacterial extracellular polymeric substances from biofilms". Gerhard-Mercator-Universitaet Duisburg, 2004. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-09132004-102114/.

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Microorganisms in biofilms are kept together by extracellular polymeric substances (EPS). The EPS are key molecules for the structure, function and organization of biofilms. Chemical and / or physical isolation methods are being used for the quantitative separation of EPS from biofilms. The yield of EPS depends on the method of isolation. Four different methods of EPS isolation were used in this work (separation by stirring and centrifugation, use of a cation exchange resin, extraction with formaldehyde and extraction with formaldehyde and NaOH) on pure culture biofilms of Pseudomonas aeruginosa and biofilms from sewage treatment systems. The isolation by stirring and centrifugation was suitable for pure culture biofilms. If calcium was present in the growth medium stirring and centrifugation alone was not sufficient. The isolation of EPS was successful with the cation exchange method. The method of choice for the isolation of EPS from environmental biofilms was the cation exchange method. EPS from pure culture biofilms of P. aeruginosa and P. fluorescens did not only consist of polysaccharides, but also of significant amounts of proteins. In environmental biofilms humic substances and DNA were found in addition to polysaccharides and proteins. Detailed studies of the EPS from P. aeruginosa showed, that the EPS consisted of 70 % (w/w) of alginate. Alginate showed a clear heterogeneity in relation to charge (acetylated and non-acetylated fraction) and molar mass. Neutral carbohydrates were not found in the EPS after total hydrolysis followed by thin layer chromatography. Proteins amounted to 28 % (w/w) of the EPS. It is assumable that this not only related to enzymes, but also structural proteins (e. g. lectins). Rhamnose lipids (mainly di-rhamno lipid) were also found in the EPS (small amount of 1 % (w/w)); these molecules may also play an important role in the development of the biofilm structure. By increasing the time of biofilm cultivation P. aeruginosa produced (related to cell number) more EPS (mainly alginate). The composition of the EPS was depending on the nutrient medium. In synthetic media high amounts of polysaccharides and almost no proteins (in contrast to rich media) were detected in the EPS. EPS of pure culture biofilms of P. fluorescens contained carbohydrates (57 % (w/w)) and proteins (28 % (w/w)). Acetyl groups (5 % (w/w)) and glucose and galactose after hydrolysis and thin layer chromatography were detected in the EPS. Possibly the exopolysaccharide of P. fluorescens is an acetylated galactoglucan. In the analyzed sludges of waste water treatment proteins followed by carbohydrates made up the main components of the EPS. Humic substances and small amounts of DNA were detected in these EPS. The EPS of aquatic biofilms contained large amounts of humic substances. Uronic acids were not detected in any analyzed environmental biofilm. Therefore acidic polysaccharides in these biofilms cannot play any role in the stabilization of biofilms by cross linking the EPS with multivalent cations. Instead of that, humic substances, nucleic acids and acidic proteins could be responsible for cross linking.

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6

Jimoh, Taobat Adekilekun. "Water quality, biomass and extracellular polymeric substances in an integrated algae pond system". Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/57307.

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Abstract (sommario):

Integrated algae pond systems (IAPS) combine the use of anaerobic and aerobic bioprocesses to effect wastewater treatment. Although, IAPS as a technology process offers many advantages including efficient and simultaneous N and P removal, no requirement for additional chemicals, O2 generation, CO2 mitigation, and a biomass with potential for valorization, a lack of technological advancement and the need for large land area, has limited the reach of this technology at industrial scale. In mitigation, peroxonation was introduced as a tertiary treatment unit and its effect on COD and TSS of IAPS treated water investigated. An effort was made to characterize the soluble but persistent COD in IAPS treated water and, productivity of the HRAOP mixed liquor was investigated to gain insight into the potential use of this biomass. Results show that peroxone treatment effectively reduced COD, TSS, and nutrient load of IAPS water without any significant impact on land area requirement. Indeed, summary data describing the effect of peroxone on quality of IAPS-treated water confirmed that it complies with the general limit values for either irrigation or discharge into a water resource that is not a listed water resource for volumes up to 2 ML of treated wastewater on any given day. Extraction followed by FT-IR spectroscopy was used to confirm albeit tentatively, the identity of the soluble but persistent COD in IAPS treated water as MaB-floc EPS. Results show that MaB-flocs from HRAOPs are assemblages of microorganisms produced as discrete aggregates as a result of microbial EPS production. A relationship between photosynthesis and EPS production was established by quantification of the EPS following exposure of MaB-flocs to either continuous light or darkness. Several novel strains of bacteria were isolated from HRAOP mixed liquor and 16S ribosomal genomic sequence analysis resulted in the molecular characterization of Planococcus maitriensis strain ECCN 45b. This is the first report of Planococcus maitriensis from a wastewater treatment process. Productivity and change in MaB-flocs concentration, measured as mixed liquor suspended solids (MLSS) between morning and evening were monitored and revealed that MLSS is composed of microalgae and bacteria but not fungi. Concentration varied from 77 mg L-1 in September (winter) to 285 mg L-1 in November (spring); pond productivity increased from 5.8 g m-2 d-1 (winter) to 21.5 g m-2 d-1 (spring); and, irrespective of MLSS concentration in late afternoon, approximately 39% was lost overnight, which presumably occurred due to passive removal by the algae settling pond. The outcomes of this research are discussed in terms of the quality of treated water, and the further development of IAPS as a platform technology for establishing a biorefinery within the wastewater treatment sector.

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7

Bura, Renata. "Properties and occurrence of lipids in extracellular polymeric substances (EPS) of activated sludge flocs". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0023/MQ50331.pdf.

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8

Haslett, Norman G. "Factors influencing the production and nature of surface-associated Pseudomonas fragi extracellular polymeric substances (EPS)". Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295391.

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9

Leung, Pui-chi, e 梁佩芝. "Effects of extracellular polymeric substances on the bioflocculation and sedimendation of diatom blooms and activated sludge". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29512153.

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10

Milner, Clare. "The possible role of the extracellular polymeric substances (EPS) of Staphylococcus epidermidis in biomaterial-centered infections". Thesis, University of Aberdeen, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320235.

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The aim of this project was to determine the possible role of the extracellular polymeric substances (EPS) of Staphylococcus epidermidis in biomaterial-centered infections. The first part of the project involved the production, isolation, and characterisation of S.epidermidis EPS. A novel method for the isolation of EPS from complex medium was developed which was able to eliminate the problems associated with contamination of bacterial EPS by medium components. Using this method, samples of EPS were obtained from S.epidermidis ATCC 35984 and clinical isolates. In the second part of the project, studies were carried out in order to determine the effect of EPS-eradicating treatments on (a) the susceptibility of stationary phase planktonic cultures to antibiotics, and (b) the integrity of intact biofilms. Eradication of EPS was achieved by exposure of planktonic stationary phase cultures of a clarithromycin-resistant strain of S.epidermidis (Clar^r No.6) to clarithromycin^*. This antibiotic had no effect on the growth or viability of this strain, however, exposure to clarithromycin resulted in a dose-dependent reduction in the dry weight of EPS obtained (5 μg ml^-1 = 50% reduction, 10 μg ml^-1 = 65% reduction). This result was also achieved with stationary phase cultures of a clarithromycin-sensitive strain of S.epidermidis (16595A). The effect of clarithromycin exposure (EPS eradication) on the subsequent efficacies of the antibiotics teicoplanin, cefuroxime and ciprofloxacin, towards stationary phase planktonic cultures of S.epidermidis Clar^r No.6 was determined by total and viable cell counts. No effect on cell viability was observed for combinations of clarithromycin and teicoplanin or ciprofloxacin. However, the 2 to 3 log reduction in viability that was observed for combinations of clarithromycin and cefuroxime suggested that these two antibiotics may have been working in synergy. ^* Clarithromycin is a macrolide antibiotic which is thought to act on the 50 S ribosomal subunit of bacteria which will then interfere with protein synthesis and in turn lead to inhibition of bacterial growth.

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11

Taylor, Joe D. "Response of microbial communities in estuarine littoral zones to changes in environment and extracellular polymeric substances". Thesis, University of Essex, 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.537947.

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12

XUE, ZHENG. "Role of Extracellular Polymeric Substances (EPS) on Biofilm Disinfection in a Model Drinking Water Distribution System". University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1349714910.

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13

Zhang, Ruiyong [Verfasser], e Wolfgang [Akademischer Betreuer] Sand. "Biofilm formation and extracellular polymeric substances of acidophilic metal/sulfur-oxidizing archaea / Ruiyong Zhang. Betreuer: Wolfgang Sand". Duisburg, 2016. http://d-nb.info/108189962X/34.

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14

Li, Qian [Verfasser], e Wolfgang [Akademischer Betreuer] Sand. "Extracellular polymeric substances involved in adhesion and biofilm formation by Sulfobacillus thermosulfidooxidans / Qian Li ; Betreuer: Wolfgang Sand". Duisburg, 2017. http://d-nb.info/1143518675/34.

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15

Windhues, Thorsten. "Physikalisch-chemische Charakterisierung von extrazellulären polymeren Substanzen und deren Alginatkomponenten mit Streulichtmethoden - Physico-chemical characterization of extracellular polymeric substances and their alginate components with light scattering techniques". Gerhard-Mercator-Universitaet Duisburg, 2002. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-11192002-174358/.

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Abstract (sommario):

Algal alginates are of great importance for industrial applications. Since their properties depend on the kind of algae and the time of harvesting, supply problems caused price fluctuations. Hence, current research focuses on alternative alginate sources. Back in the 60s, exopolysaccharides similar to algal alginates were found. They were produced by mucoid Pseudomonas aeruginosa strains which embed themselves in a slime matrix containing bacterial alginates. The focus of this thesis was a comparisons of the physico-chemical properties of bacterial and algal alginates. The main results of the performed investigations are as follows: a) both substances aggregate in highly diluted solutions, b) bacterial alginates have a bigger molar mass than algal alginates, c) their mean squared radii of gyration are bigger than those of algal alginates, d) the second osmotic virial coefficients of these systems are negative and temperature dependent, e) acetylation of alginates support the aggregation, f) bacterial alginate do not gel analog to the egg box mechanism.

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16

Hessler, Christopher Mark. "The Influence of Capsular Extracellular Polymeric Substances on the Toxicological Interaction Between Titanium Dioxide Nanoparticles and Planktonic Bacteria". University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1321645743.

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17

Henry, Victoria Azula. "Identification of functional group characteristics and physicochemical properties of atrazine degrading Pseudomonas sp. strain ADP biofilm". Diss., University of Iowa, 2015. https://ir.uiowa.edu/etd/5947.

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Microbial biofilms are significant in a variety of settings including the human microbiome, infectious disease, industrial processes, and environmental remediation. Due to the ubiquitous nature of biofilms, there is a great interest in understanding cellular activities within the biofilm matrix. Biofilm cells are able to better withstand environmental stress, experience increased horizontal gene transfer, and live longer. The purpose of this research is to grow Pseudomonas sp. strain ADP as a biofilm and examine the chemical and physical characteristics the microbe undertakes in a sticky extracellular matrix. ADP is the organism of choice because of its ability to metabolize atrazine. Cells are grown in a drip biofilm reactor and flow cells under varying time lapse to gain insight to biofilm formation. Some cells are grown with atrazine as the sole nitrogen source, while others are grown in a nutrient-rich medium to compare cells response under nutrient-limited conditions with atrazine particles in the matrix. As a positive control, Escherichia coli are grown in a similar manner. Raman spectroscopy was the main analytical technique used to evaluate the chemical and molecular characteristics of this system. Scanning electron microscopy is used to examine cellular distribution, and several assays are performed for molecular composition analysis. Raman analysis in the fingerprint region revealed distinct differences between free cells and cells in biofilm. Soluble extracellular polymeric substances (EPS) were found to be more prevalent than tightly bound EPS and lightly bound EPS in the biofilm matrix. Comparison of relative peak intensity ratios suggests that it is possible to track atrazine degradation by means of intermediates using Raman spectroscopy. SEM micrographs revealed EPS role as an immobilizing agent when in contact with compounds, such as atrazine. Further research is needed to determine if atrazine can bind to EPS fractions outside the presence of cells and whether its affinity to EPS is mostly attributed to physical conditions, due to the architecture of biofilm, or chemical, based on functional groups presents. The results obtained from this research will contribute to the development of a less invasive microscale approach to address the acquisition and induction of biotransformation activity occurring in xenobiotic degrading systems. The extracellular interactions observed can be used to further characterize biofilm-mediated bioremediation. Results have contributed to the Raman spectra library for microorganisms and organic compounds. .

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18

Salisbury, Stephanie Kara. "Dynamics and Composition of the Extracellular Polymeric Substances Produced by Benthic Microalgae: An in Situ 13C and 15N Approach". W&M ScholarWorks, 2011. https://scholarworks.wm.edu/etd/1539617901.

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The land-‐ocean margin is characterized by a shallow water column, which allows light to reach the benthos and supports a diverse community of benthic autotrophs. One group of benthic autotrophs, consisting of benthic diatoms, cyanobacteria and other photosynthetic microorganisms living near the sediment surface (i.e., benthic microalgae) accounts for a substantial amount of this primary production. Benthic microalgae are also tightly coupled to carbon and nutrient cycling processes carried out by the sediment bacterial community. Benthic microalgae exude complex biopolymers, called extracellular polymeric substances (EPS), which consist mainly of carbohydrates, but can contain proteins and nucleic acids. EPS serves multiple functions for the benthic microalgae including: sediment attachment and stabilization and provides a labile substrate that may facilitate the tight coupling between benthic microalgae and sediment bacteria. A novel experimental apparatus, called the perfusionator, was used to examine carbon and nitrogen cycling through the benthic microalgal and sediment bacterial communities during a 48-‐day field experiment. Dual stable isotopic tracers (H13CO3-‐ and 15NH4+) were added to the porewater within the perfusionators to trace carbon and nitrogen cycling through inorganic and organic pools in order to assess the role of benthic microalgae in sediment nutrient cycling and sequestration. Physical and biological processes were characterized by: (1) installing covers over half of the perfusionators on day 14 to dampen physical mixing and sediment reworking, (2) using glass beads to track sediment mixing and reworking within the perfusionators, (3) continuous measurements of current speeds using an acoustic Doppler velocimeter and (4) monitoring a suite of environmental variables. The dominant feature of the experimental period was a harmful algal bloom (chl a concentrations peaked on day 14 at 107 μg L-‐1) dominated by Cochlodinium polykrikoides, which reduced biomass of benthic microalgae. Sediment total organic carbon and nitrogen (TOC and TN), benthic microalgae isolated through Ludox extractions, and EPS were enriched in 13C and 15N during the labeling period. Two fractions of EPS were extracted from the sediments, a hot water (HW-‐EPS) or intracellular fraction and a hot bicarbonate (HB-‐EPS) or extracellular fraction. Concentrations of HB-‐EPS were higher than HW-‐ EPS, but the HW-‐EPS showed enrichment in 13C before the HB-‐EPS, consistent with its association with photosynthetic pathways inside the cell. The carbohydrate content of the EPS was higher later in the experiment when sediment chlorophyll concentrations were lower. The carbohydrate composition of the EPS indicated that a higher proportion of material was probably derived from sources other than benthic microalgae including bacterial sources. Increased concentrations of phaeopigments in surface sediments corroborated increased contributions from decaying or degraded material, likely derived from the harmful algal bloom. Overall, this field experiment traced carbon and nitrogen through the benthic microalgal community in a shallow coastal system, and captured the response of the system to a harmful algal bloom event. This experiment provided new insights about carbon and nitrogen dynamics within shallow systems and benthic microalgae community responses to key environmental events.

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19

Park, Chul. "Extracellular Polymeric Substances in Activated Sludge Flocs: Extraction, Identification, and Investigation of Their Link with Cations and Fate in Sludge Digestion". Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/28504.

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Abstract (sommario):

Extracellular polymeric substances (EPS) in activated sludge are known to account for the flocculent nature of activated sludge. Extensive studies over the last few decades have attempted to extract and characterize activated sludge EPS, but a lack of agreement between studies has also been quite common. The molecular makeup of EPS has, however, remained nearly unexplored, leaving their identity, function, and fate over various stages in the activated sludge system mainly unknown. In spite of their critical involvement in bioflocculation and long history of related research, our understanding of EPS is still greatly limited and better elucidation of their composition and structure is needed. The hypothesis of this research was that activated sludge floc contains different fractions of EPS that are distinguishable by their association with certain cations and that each fraction behaves differently when subjected to shear, aerobic digestion, anaerobic digestion and other processes. In order to examine this floc hypothesis, the research mainly consisted of three sections: 1) development of EPS extraction methods that target cations of interest (divalent cations, especially calcium and magnesium, iron, and aluminum) from activated sludge; 2) molecular investigations on activated sludge EPS using metaproteomic analyses, comprising sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and protein identification by liquid chromatography tandem mass spectrometry (LC/MS/MS), and hemaagglutination (HA)/HA inhibition assays; and 3) investigating the fate of EPS in sludge digestion using SDS-PAGE. Evaluation of prior research and data from preliminary studies led to the development of the three extraction methods that were used to target specific cations from activated sludge and to release their associated EPS into solution. These methods are the cation exchange resin (CER) procedure for extracting Ca²⁺+Mg²⁺, sulfide extraction for removing Fe, and base treatment (pH 10.5) for dissolving Al. The cation selectivity in the three extraction methods, the composition of EPS (protein/polysaccharide), amino acid composition, and a series of sequential extraction data established initial research evidence that activated sludge EPS that are associated with different cations are not the same. SDS-PAGE was successfully applied to study extracellular proteins from several sources of both full- and bench-scale activated sludges. The three extraction methods led to different SDS-PAGE profiles, providing direct evidence that proteins released by the three methods were indeed different sludge proteins. Another important outcome from this stage of research was finding the similarity and differences of extracellular proteins between different sources of activated sludge. SDS-PAGE data showed that many of CER-extracted proteins were well conserved in all the sludges investigated, indicating that a significant fraction of Ca²⁺ and Mg²⁺-bound proteins are universal in activated sludge. On the other hand, protein profiles resulting from sulfide and base extraction were more diverse for different sludges, indicating that Al and Fe and their associated proteins are quite dynamic in activated sludge systems. Protein bands at high densities were analyzed for identifications by LC/MS/MS and several bacterial proteins and polypeptides originating from influent sewage were identified in this study. This was also thought to be the first account of protein identification work for full-scale activated sludge. The analysis of SDS-PAGE post sludge digestion revealed that CER-extracted proteins remained intact in anaerobic digestion while they were degraded in aerobic digestion. While the fate of sulfide-and base-extracted proteins in aerobic digestion was not as clearly resolved, their changes in anaerobic digestion were well determined in this research. Sulfide-extracted protein bands were reduced by anaerobic digestion, indicating that Fe-bound EPS were degraded under anaerobic conditions. While parts of base-extracted proteins disappeared after anaerobic digestion, others became more extractable along with the extraction of new proteins, indicating that the fate of base-extractable proteins, including Al-bound proteins, is more complex in anaerobic digestion than CER-extracted and sulfide-extracted proteins. These results show that Ca²⁺+Mg²⁺, Fe³⁺, and Al³⁺ play unique roles in floc formation and that each cation-associated EPS fraction imparts unique digestion characteristics to activated sludge. Finally, since a considerably different cation content is quite common for different wastewaters, it is postulated that this variability is one important factor that leads to different characteristics of activated sludge and sludge digestibility across facilities. The incorporation of the impact of cations and EPS on floc properties into an activated sludge model might be challenging but will assure a better engineering application of the activated sludge process.
Ph. D.

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20

Brian-Jaisson, Florence. "Identification et caractérisation des exopolymères de biofilms de bactéries marines". Phd thesis, Toulon, 2014. http://tel.archives-ouvertes.fr/tel-01058255.

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Dans l'environnement marin, les surfaces artificielles sont rapidement colonisées par des bactéries qui s'organisent en communautés appelées biofilms, s'entourant d'une matrice de substances polymériques extracellulaires (EPS). La formation d'un biofilm est une étape critique du processus nommé biofouling, c'est-à-dire l'accumulation de micro- et de macro-organismes sur une surface immergée, pouvant conduire à des conséquences néfastes dans le secteur marin. Dans cette étude, il s'agit d'identifier des souches bactériennes isolées de supports immergés en Mer Méditerranée et de les caractériser phénotypiquement par diverses approches. Leur capacité à former un biofilm in vitro a été évaluée dans différentes conditions avec une attention particulière portée sur leurs capacités à produire une matrice polymérique abondante riche en polysaccharides; l'objectif étant d'isoler des exopolysaccharides originaux à activité antifouling. Treize souches ont ainsi fait l'objet d'analyses phylogénétiques et d'une caractérisation phénotypique. Sept genres et douze espèces différentes ont été identifiés au sein desquelles deux isolats peuvent être affiliés à une nouvelle espèce, nommée Persicivirga mediterranea. Ce genre n'a jamais été décrit en Mer Méditerranée jusqu'à présent. L'extraction des EPS de chaque souche cultivée en biofilm a permis de déterminer leur composition générale en glucides, protéines, acides nucléiques et lipides. Une souche, Pseudoalteromonas ulvae TC14, se distingue par sa capacité à produire des exopolysaccharides en quantité importante. Il s'agit essentiellement de polymères du glucose dont les analyses chromatographiques et spectroscopiques ont révélé la diversité de taille (Mw ~ 1-4000 kDa), de charge (neutre ou anionique) et de fonction associée (lactate ou acétate). Les fractions d'EPS enrichies en polysaccharides inhibent la formation de biofilm par d'autres souches marines. Ces derniers sont également synthétisés par les bactéries en culture planctonique mais en proportions très différentes.

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21

Michalowski, Witold Dariusz [Verfasser], Hans-Curt [Akademischer Betreuer] Flemming e Ulrich [Akademischer Betreuer] Szewzyk. "Composition, dynamics and function of extracellular polymeric substances in drinking-water biofilms / Witold Dariusz Michalowski. Gutachter: Ulrich Szewzyk. Betreuer: Hans-Curt Flemming". Duisburg, 2012. http://d-nb.info/1028324421/34.

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22

Teubner, Natascha Caroline [Verfasser], e Wolfgang [Akademischer Betreuer] Sand. "Functional components in the EPS -extracellular polymeric substances- of the iron-oxidizing biofilm forming Acidithiobacillus species / Natascha Caroline Teubner ; Betreuer: Wolfgang Sand". Duisburg, 2018. http://d-nb.info/115849601X/34.

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23

Teubner, Natascha [Verfasser], e Wolfgang [Akademischer Betreuer] Sand. "Functional components in the EPS -extracellular polymeric substances- of the iron-oxidizing biofilm forming Acidithiobacillus species / Natascha Caroline Teubner ; Betreuer: Wolfgang Sand". Duisburg, 2018. http://d-nb.info/115849601X/34.

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24

Wang, Zhikang. "Influence of Biofilm on Disinfection Byproducts Formation and Decay in a Simulated Water Distribution System". University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1372343403.

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25

Stuchlíková, Olga. "Antimikrobiální aktivita uhlíkatého plniva". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-217047.

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Abstract (sommario):

Diplomová práce se zabývá vlivem uhlíkatého plniva na životaschopnost a produkci extracelulárních látek vybrané bakterie Bacillus subtilis (CCM 1999) a kvasinky Yarrowia lipolytica (CCY 29-26-52). Antimikrobiální aktivita těchto částic, přítomných v kultivačním mediu, byla sledována pomocí následujících parametrů: růst daného mikroorganismu, produkce extracelulárních proteinů a v poslední řadě byla monitorována produkce extracelulárních polymerních substancí, které mají úzkou souvislost s tvorbou biofilmu. Suspenze materiálů (0,135 mg/mL) byly připraveny ve dvou rozdílných kultivačních mediích; tzn. živné medium s obsahem glukózy pro Bacillus subtilis a bazální medium s přídavkem Tweenu 80 pro Yarrowia lipolytica, a media byla inokulována příslušným typem mikroorganismu. Experimenty probíhaly po dobu 6 dnů při rychlosti třepání 160 rpm a teplotě 30 °C pro Bacillus subtilis a 28 °C pro Yarrowia lipolytica. Testovány byly celkem tři typy uhlíkatého nanomateriálu, získané z Katedry anorganické chemie, Vysoké školy chemicko-technologické v Praze. Tyto materiály specifikované jako materiál “A”, “B” a “C” se navzájem lišily velikostí částic a stupněm oxidace. Na základě skríningových studií byla vybrána koncentrace testovaného materiálu 0,135 mg/mL a rychlost třepání 160 rpm. Metodou měření optické hustoty vzorku při 600 nm byly sestaveny a porovnány růstové křivky obou mikroorganismů v přítomnosti testovaných nanočástic po dobu 5 dní. Tímto způsobem bylo zjištěno, že přítomnost nanočástic v mediu nemá velký vliv na růst zkoumaného mikroorganismu. Tato metoda, je však pouze orientační, protože se nevyhneme chybě díky přítomnosti mrtvých buněk. Dále byla testována produkce celkových a extracelulárních proteinů daným mikroorganismem v přítomnosti testovaných nanočástic. Nebyla však pozorována výrazná odchylka hodnot od hodnot kontrolního vzorku, který neobsahoval testovaný materiál. Na základě metod počítání kolonií (Bacillus subtilis) a buněk (Yarrowia lipolytica) byly určeny ztráty životaschopnosti mikroorganismu ve 3 časech (6, 48 a 144 hodin); v kratším časovém intervalu byl růst spíše podporován. Dále byla monitorována produkce extracelulárních polymerních substancí (EPS), tedy proteinů, redukujících substancí a polysacharidů. Tyto látky byly vylučovány daným mikroorganismem do prostředí v průběhu 24 hodin. Bacillus subtilis produkoval EPS ve větší míře než Yarrowia lipolytica. Předpokládáme, že produkce EPS by mohla souviset s tvorbou biofilmu, který chrání buňky před toxicitou nanočástic.

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26

Andersson, Sofia. "Characterization of Bacterial Biofilms for Wastewater Treatment". Doctoral thesis, KTH, Miljömikrobiologi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10118.

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Research performed at the Division of Environmental Microbiology has over the last years resulted in the isolation of possible bacterial key-organisms with efficient nutrient removal properties (Comamonas denitrificans, Brachymonas denitrificans, Aeromonas hydrophila). Effective use of these organisms for enhanced nutrient removal in wastewater treatment applications requires the strains to be retained, to proliferate and to maintain biological activity within theprocess. This can be achieved by immobilization of the organisms using an appropriate system.Two putative immobilization systems, agar entrapment and biofilm formation, wereassessed. Surface attached biofilm growth provided better results with respect to cell retention,proliferation and microbial activity than immobilization in agar beads. Thus, biofilm physiology was further characterized using simplified systems of single, dual or multi strain bacterial consortia containing the key-organisms as well as other wastewater treatment isolates. Mechanisms for initial adherence, biofilm formation over time, dynamics and characteristics of extracellular polymeric substances (EPS) and exopolysaccharides, nutrient removal activity as well as the effect of bacterial interactions were investigated. The results showed that all theassessed bacterial strains could form single strain biofilm providing that a suitable nutrientsupply was given. Production of EPS was found to be critical for biofilm development and both EPS and polysaccharide residue composition varied with bacterial strain, culture conditions and biofilm age. Denitrification and phosphorus removal activity of the keyorganisms was maintained in biofilm growth. Co-culturing of two or more strains resulted in both synergistic and antagonistic effects on biofilm formation as well as the microbial activitywithin the biofilm. Bacterial interactions also induced the synthesis of new polysaccharideswhich were not produced in pure strain biofilms.The complexity of single and mixed strain biofilm development and the implications of interactions on biofilm performance were underlined in this study. The data presented can be useful for modeling of biofilm systems, serve as a tool for selection of bacterial strain combinations to use for bioaugmentation/bioremediation or provide a base for further experiment design.
QC 20100622

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27

Roberts, Zoe Elizabeth. "The lipid biomarker distribution of cold seep mats and the possible influence of extracellular polymeric substances on calcium carbonate formation associated with the anaerobic oxidation of methane". Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520212.

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28

Unal, Eda. "Investigation Of Magnesium Ions Effect On Sludge Properties In Phosphorus Deficient Bioreactors". Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612620/index.pdf.

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The activated sludge process efficiency depends on separation of microbial cells from treated wastewater. Separation can fail due to a number of problems. One of these problems is sludge bulking which is non-settling situation of biomass. Former studies showed that phosphorus deficiency caused filamentous sludge bulking with increasing magnesium ion concentrations. The main objectives of this study are to find out the effect of magnesium ions on sludge properties in phosphorus deficient medium and to determine if there is any bulking. Three different concentrations of magnesium (0.5, 5, 15 meq/L) were added to three bioreactors which contained phosphorus deficient medium. In first set C: N: P ratio was 100:5:0.05. In second set, C:N:P ratio was elevated to 100:5:1. At steady state, physical characteristics including sludge volume index (SVI), viscosity, turbidity and dewaterability were determined. Besides concentration of extracellular polymeric substances (EPS) as well as conductivity was measured. By using API kits, bacterial identification was achieved. In first set phosphorus deficiency and increasing magnesium ion concentration caused filamentous bulking. Carbohydrate content of extracellular polymeric substance significantly increased by magnesium addition. Dewaterability of the system got worse and viscosity decreased. Sludge Volume Index (SVI) indicated severe bulking at all magnesium concentrations. By using biochemical tests microorganisms dominant in the system were determined In second set, all of the parameters indicated healthy flocculation. By magnesium addition, EPSp and EPSc increased. Dewaterability and settleability, improved by the presence of phosphorus with close values measured at different magnesiuim concentrations. Nocardia related genera of Corynebacterium and Enteric microorganisms were identified.

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29

Avella, Vasquez Ana Catalina. "Substances polymériques extracellulaires dans les procédés de traitement des eaux usées". Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL029N/document.

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L’objectif de ce travail est d’une part (i) étudier le comportement de la biomasse notamment la production d’EPS en présence des composés pharmaceutiques (un agent anticancéreux et cinq antibiotiques); et d’autre part, (ii) étudier les EPS dans le contexte de décantation des boues en présence d’agents fongiques et en situations réelles dans des stations d’épuration. L’étude en présence de l’agent anticancéreux a été réalisée dans des bioréacteurs à membranes. La présence de l’agent anticancéreux a induit l’augmentation de la production d’EPS agissant comme un mécanisme de protection microbienne qui était à l’origine du colmatage des membranes. L’effet de cinq antibiotiques a été évalué en réacteur batch. La famille des macrolides a montré un effet plus important sur l’activité microbienne avec une augmentation significative de la production d’EPS associée à un mécanisme de protection. La décantation des boues en présence des cultures fongiques a été conduite en réacteur pilote. Une amélioration spectaculaire de la décantation a été liée à une meilleure cohésion au sein des flocs imputable en grand partie à l’augmentation de la production d’EPS. Enfin, le diagnostic du procédé de traitement des eaux a été établi sur trois stations d’épuration des papeteries grâce à une double approche d’une part l’analyse physico-chimique des boues et d’autre part, l’exploitation statistique d’analyse en composantes principales (ACP) des paramètres technologiques enregistrées dans chaque station. Nous avons tenté d’exprimer sous forme de régressions linéaires ou polynomiales de deuxième degré, la décantation en fonction d’une quantité réduite des paramètres mesurés
The objective of this work is firstly, i) to study the microbial behaviour of the biomass especially the production of the EPS in the presence of pharmaceutical compounds (an anticancer product and five antibiotics); and secondly, ii) to study EPS in the context of the sludge settling in wastewater treatment plants. The study in the presence of the anticancer product was done in membrane bioreactors. The presence of the anticancer product provoked the production of the EPS as the protection mechanism which is at the origin of the membrane fouling.The effect of five antibiotics was evaluated in batch reactors. The family of macrolides showed the most important effect on the microbial activity with a significant increase of the EPS production which was associated with a protection mechanism.Sludge settling in the presence of fungi was carried out in a pilot reactor. The spectacularly improvement of the sludge settleability was related with a better cohesion inside of the flocs attributed to an increase of the EPS production.Finally, the diagnosis of different wastewater treatment processes was established in three paper mill wastewater treatment plants thanks to the double approach used here, the physico-chemical analysis of the sludge and the statistical analysis by principal components analysis of the different parameters recorded in each plant. We tried to describe the parameter related to the settling behaviour by linear or polynomial regressions of second degree in function of a reduced number of the measured parameters

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30

Zethof, Jeroen H. T. [Verfasser], Karsten [Gutachter] Kalbitz, Karsten [Akademischer Betreuer] Kalbitz, Georg [Gutachter] Guggenberger e M. Estela [Gutachter] Nadal-Romero. "The role of extracellular polymeric substances from microbes in soil aggregate stabilization in semiarid grasslands / Jeroen H.T. Zethof ; Gutachter: Karsten Kalbitz, Georg Guggenberger, M. Estela Nadal-Romero ; Betreuer: Karsten Kalbitz". Dresden : Technische Universität Dresden, 2021. http://d-nb.info/1237320054/34.

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31

Turtin, Ipek. "Investigation Of Activated Sludge Bioflocculation: Influence Of Magnesium Ions". Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606605/index.pdf.

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Abstract (sommario):

Activated sludge systems are the most widely used biological wastewater treatment processes all over the world. The main working principles of an activated sludge system are the oxidation of biologically degradable wastes by microorganisms and the subsequent separation of the newly formed biomass from the treated effluent. Separation by settling is the most troublesome stage of an activated sludge process. A decrease in the efficiency of the separation of microbial biomass from the treated effluent causes a decrease in the overall efficiency of the treatment plant. The efficiency of the separation process is related to the bioflocculation, which can be briefly defined as the aggregation of the bacteria into flocs through flocculation. Bioflocculation depends on the extracellular polymers (EPS) that are produced by microorganisms. The operating conditions of the activated sludge system is a key determinant of the synthesis of EPS and bioflocculation. The main objective of this study is to find out the effect of magnesium ions on the bioflocculation process under phosphorus deficient and sufficient conditions. In order to achieve this aim, the effects of magnesium ion in 4 different concentrations (0.9, 5, 10 and 20 meq/L) are investigated in semi continuous reactors. The reactors are operated at a mean cell residence time of 8 days and 20º
C temperature. When reactors are confirmed to be at steady state, several sets of analysis are conducted. In particular, the surface chemical parameters including EPS and its components, electrical charge, and hydrophobicity as well as physical properties such as settlability, filterability, viscosity, floc strength, and turbidity are examined. It has been understood that phosphorus deficiency causes severe filamentous bulking under magnesium rich conditions. Increasing the phosphorus concentration in the influent can cure this problem. After the sludges are cured some granular structures were observed in the microscopic investigations and they are thought to be polyphosphate granules in which microorganisms tend to accumulate phosphorus when they find the adequate source after a starvation period. To consider the reactors operated at phosphate present conditions, it has been found that EPS increases with increasing influent magnesium concentration. However, protein type EPS (EPSP) exhibits a sharper increase when compared to the carbohydrate type EPS (EPSC) indicating the selective attitude of magnesium ions to protein type of polymers. It has been understood that the increase in the influent magnesium concentration results in an increase in dewaterability and zone settling velocity, and a decrease in the viscosity. Hydrophobicity was found to exhibit a maximum value at 10 meq/L magnesium fed sludge and then it dropped back. Surface charge values also made a minimum at 10 meq/L reactor and then no change occurred at the increase of the magnesium concentration to 20 meq/L. Finally, COD values were found to increase with the increasing magnesium concentration due to the increasing EPS.

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32

Kara, Fadime. "Investigation Of Sodium And Potassium Ions In Relation To Bioflocculation Of Mixed Culture Microorganisms". Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608488/index.pdf.

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Bioflocculation happens naturally and microorganisms aggregate into flocs during wastewater treatment. It is critical to understand the mechanisms of bioflocculation and its impact on the following solid/liquid separation process since seperation by settling is one of the key aspects that determine the efficiency and the overall economy of activated sludge systems. Bioflocculation occurs via extracellular polymeric substances (EPS) and cations by creating a matrix to hold various floc components together so the cations become an important part of the floc structure. The main objective of this study is to investigate the effects of monovalent cations specifically potassium and sodium (K and Na) on the bioflocculation, settleability and dewaterability of activated sludge. The particular aim is to grow the mixed culture microorganisms in the presence of specific cation so that the effect of cation on the stimulation of EPS production can be seen. In order to achieve this aim, semi-continuous reactors were separately operated at concentrations of 5, 10, and 20 meq/L of each cation with mixed culture bacteria and fed with synthetic feed medium representing influent to the activated sludge systems. Also, a control reactor at low cation dose was operated for each reactor set. The effective volume of the reactors was 2 L with 8 days of sludge residence time (SRT) and pH was kept at 7.7±
0.3. The activated sludge reactors were operated until the reactors reached steady state and then related analyses were conducted. It was found that addition of potassium and sodium ions at increasing concentrations resulted in increase in total polymer concentration. However, potassium ions promoted the synthesis of both polysaccharide and protein type polymers whereas sodium ions tended to stimulate production of protein type polymers and had an affinity to bind more protein within the floc structure. Sodium sludges had lower hydrophobicity and higher surface charges, so sodium ions led to deterioration in flocculation of sludges. Addition of both these ions decreased the dewaterability, sodium ions had more detrimental effect on dewaterability of sludges compared to potassium ions. The examination of data related to settleability showed that potassium ions led to no drastic deterioration in settling characteristics of the activated sludge but the addition of sodium ions deteriorated the settleability. In addition, it was seen that while the addition of potassium ions to the feed led to a decrease in viscosity, increase in sodium concentration correlated with an increase in viscosity. Finally, the comparison of chemical oxygen demand (COD) removal efficiency of these cations showed that sodium is more efficient in COD removal.

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33

Henriques, InÃªs Domingues. "Elucidating the Response of Activated Sludge Cultures to Toxic Chemicals at the Process, Floc and Metabolic Scales". Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/27937.

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Abstract (sommario):

Activated sludge treatment systems rely on a microbial consortium structurally organized in bioflocs to treat pollutants present in wastewater. The treatment process efficiency in these systems can be severely affected by toxic chemicals present in the influent wastewater. The effects of chemical toxins at the treatment process level are determined by the mechanisms that occur at the biofloc and cellular levels, which can be physical, chemical and physiological in nature. We believe that the overall process effects of chemical toxins on activated sludge systems likely result from a combination of all three types of mechanisms and that they are interdependent, in the sense that specific bacterial stress response mechanisms (physiological mechanisms that protect the cell from toxic conditions) may lead to physical/chemical alterations at the floc level, and vice-versa. Ultimately, understanding the mechanisms that occur at the floc and metabolic scales will help to design more robust and efficient treatment systems, and to develop tools to prevent and mitigate the effects of toxic chemicals on activated sludge systems. In this research, we set out to establish the link between the effects of chemical toxins on activated sludge cultures at the process, floc and metabolic scales. First, the effects of shock loads of different toxic sources (1-chloro-2,4-dinitrobenzene (CDNB), cadmium, 1-octanol, 2,4-dinitrophenol (DNP), weakly complexed cyanide, pH 5, 9 and 11, and high ammonia levels) on activated sludge process parameters (biomass growth, respiration rate, flocculation, chemical oxygen demand (COD) removal, dewaterability and settleability) were studied. For all chemical shocks except ammonia and pH, concentrations that caused 15, 25 and 50% respiration inhibition were used to provide a single pulse chemical shock to sequencing batch reactor (SBR) systems containing a nitrifying (10 day solids retention time – SRT) and a non-nitrifying (2 day SRT) biomass. We found that cadmium and pH 11 shocks were the conditions that most detrimentally affected all the processes, followed by CDNB. DNP and cyanide primarily led to effects on respiration, while pH 5, 9, octanol and various ammonia concentrations did not impact the treatment process to a significant extent. Additionally, there was a clear correlation between biomass deflocculation and increases in the effluent soluble COD of the shocked reactors for different chemical sources. With this study, we were able to establish a source-effect matrix linking classes of chemical toxins to their potential inhibitory effects on activated sludge processes, thereby contributing to a better understanding of the potential effects of toxic industrial discharges into biological treatment systems. The findings of the first phase of the research, specifically the correlation between chemical-induced deflocculation and increases in soluble COD, served as a motivation to explore the role of floc structure in the response of activated sludge cultures to toxic compounds, and to conduct a more in-depth analysis of the supernatant (soluble phase) of toxin-exposed activated sludge. In one study, we evaluated the respiration inhibition induced by octanol, cadmium, N-ethylmaleimide (NEM), cyanide and DNP on activated sludge biomasses with different floc structures but similar physiological characteristics, with the objective of assessing the role of the extracellular polymeric substances (EPS) in flocs as a protection barrier against chemical toxins. Mechanical shearing was applied to fresh mixed liquor to produce biomasses with different floc structure properties and specific oxygen uptake rate assays were conducted on the sheared and unsheared mixed liquors. The results showed that the respiration inhibition by octanol and cadmium was more intense in sheared mixed liquor (which had less EPS material available in the flocs and smaller floc sizes) than in the unsheared biomass. Conversely, the respiration inhibition induced by NEM and cyanide was similar for the different mixed liquors tested. These results allowed us to conclude that the EPS matrix functions as a protective barrier for the bacteria inside activated sludge flocs to chemicals that it has the potential to interact with, such as hydrophobic (octanol) and positively-charged (cadmium) compounds, but that the toxicity response for soluble, hydrophilic toxins (NEM and cyanide) is not significantly influenced by the presence of the polymer matrix. In the final study that was conducted, we used the metabolomics-based technique metabolic footprinting to assess if the soluble phase of mixed liquor exposed to different chemical toxins exhibited a toxin-specific biochemical composition. We hypothesized that toxin-specific effects could be distinguished through footprint patterns of those soluble samples. The impact of cadmium, DNP and NEM shock loads on the composition of the soluble fraction of activated sludge mixed liquor was analyzed by liquid chromatography-mass spectrometry (LC-MS). The results from this study indicated that there was a significant release of biomolecules (proteins, carbohydrates and humic acids) from the floc structure into the bulk liquid due to chemical stress. More importantly, using a multivariate statistical method called discriminant function analysis with genetic algorithm variable selection (GA-DFA), we were able to show that the soluble phase samples from the different reactors could be differentiated, thereby indicating that the footprints generated by LC-MS were different for the four conditions tested and, therefore, toxin-specific. These footprints, thus, contain information about specific biomolecular differences between the samples, and we found that only a limited number of m/z (mass to charge) ratios from the mass spectra data was needed to differentiate between the control and each chemical toxin-derived samples. In addition, since the experiments were conducted with mixed liquor from four distinct wastewater treatment plants, the discriminating m/z ratios may potentially be used as universal stress biomarkers. These results are promising and indicate that LC-MS may be used for the discovery of activated sludge stress biomarkers, to allow the development of new toxin detection technologies for prevention of upset events in activated sludge systems.
Ph. D.

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34

Ripley, Elliott Blake. "SETTLING PERFORMANCE IN WASTEWATER FED HIGH RATE ALGAE PONDS". DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1055.

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Although high rate algae ponds (HRAPs) are a proven wastewater treatment technology with numerous environmental, social, and economic benefits, their widespread use has been hindered by inconsistent and unreliable settling performance. Hence, the goal of this thesis is to investigate how specific operational parameters affect the settling performance of HRAPs. Nine HRAPs (30 m2 surface area, 0.3 m depth) were operated as three triplicate sets, with each set run on either a 2, 3, or 4 day HRT continuously from January 25, 2012 through April 11, 2013. Settling performance was determined (i) by measuring the TSS of Imhoff cone supernatant after 2 and 24 hours of settling and (ii) by measuring the TSS of tube settler effluent. Ponds operating on 2 - 3 day HRTs (loading rate was 24 - 36 g/m3-day csBOD5 and food to microorganism (F/M) ratio was 0.13 - 0.21 day-1) were able to settle consistently with residual TSS averaging less than 40 mg/L after 2 hours of settling time. Tube settlers showed potential as effective harvesting devices; ponds operating on a 2-day HRT averaged 27.9 ± 9.2 mg/L TSS in tube settler effluent at an overflow rate (OFR) of 9.4 L/min-m2. Microscopy analysis was performed and relationships were made between settling performance and algae dominance and floc structure.

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35

Narvekar, Sneha Pradip [Verfasser], Kai Uwe [Gutachter] Totsche e Ingrid [Gutachter] Kögel-Knabner. "Role of bacterial biofilms and extracellular polymeric substances in the colloidal stability and transport of hematite nanoparticles in synthetic porous media / Sneha Pradip Narvekar ; Gutachter: Kai Uwe Totsche, Ingrid Kögel-Knabner". Jena : Friedrich-Schiller-Universität Jena, 2017. http://d-nb.info/117760275X/34.

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36

Miller, Mark W. "Optimizing high-rate activated sludge: organic substrate for biological nitrogen removal and energy recovery". Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/78208.

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Although the A-stage high-rate activated sludge (HRAS) process destroys some of the chemical energy present in municipal wastewater, this process has been gaining attention as a viable technology for achieving energy neutrality at water resource recovery facilities. In addition to carbon capture for energy recovery, A-stages are also being utilized upstream of shortcut biological nitrogen removal (BNR) processes as these BNR processes often require a controlled influent carbon to nitrogen ratio that is lower than required for conventional BNR processes. While there is extensive knowledge on conventional activated sludge processes, including process controllers and activated sludge models, there has been little detailed research on the carbon removal mechanisms of A-stage processes operated at solids retention times (SRT) less than about one day. The overall objective of this study was to elucidate the chemical oxygen demand (COD) removal mechanisms of short SRT activated sludge processes with a specific focus on the removal of the different COD fractions under varying operating conditions including dissolved oxygen, hydraulic retention time, temperature, and SRT. Once understood, automatic process control logic was developed with the purpose of producing the influent characteristics required for emerging shortcut BNR processes and capturing the remaining COD with the intent of redirecting it to an energy recovery process. To investigate the removal and assimilation of readily biodegradable substrate (SS), this study evaluated a respirometric method to estimate the SS and active heterotrophic biomass (XH) fractions of the raw wastewater influent and effluent of an A-stage pilot process. The influent SS values were comparable to the SS values determined using a physical-chemical method, but the effluent values did not correlate well. This led to the measurement of the heterotrophic aerobic yield coefficient and decay rate of the pilot process. The yield coefficient was estimated to be 0.79±0.02 gCOD/gCOD, which was higher than the accepted value of 0.67 g/g. It was speculated that the batch respirometry tests resulted in the aerobic storage of SS and this likely contributed to the error associated with the determination of SS and XH. Therefore, physical-chemical fractionation methods were used to determine the removal of the individual COD fractions. It was concluded that the SRT was the primary control parameter and below a 0.5 day SRT the dominate COD removal mechanisms were assimilation and oxidation of readily degradable substrate and sedimentation of particulate matter. At SRTs between 0.5-1 days, COD removal became a function of hydrolysis, as adsorption of particulate and colloidal matter was maximized but not complete because of limited adsorption sites. Once adequate adsorption sites were available, effluent quality became dependent on the efficiency of bioflocculation and solids separation. While the SRT of the pilot process could not be directly controlled because of severe biofouling issues when using in situ sensors, a MLSS-based SRT controller was successfully implemented instead. The controller was able to reduce total COD removal variation in the A-stage by 90%. This controller aslo provided the capability to provide a consistent carbon to nitrogen ratio to the downstream B-stage pilot process. To ascertain the settling, dewaterability, and digestibility of the sludge produced by the pilot A-stage process, several standardized and recently developed methods were conducted. The results from these tests indicated that the A-stage had similar dewaterability and digestibility characteristics to primary sludge with average achievable cake solids of 34.3±0.4% and average volatile solids reduction (VSR) of 82±4%. The A-stage sludge also had an average specific methane yield of 0.45±0.06 m3CH4/kgVS. These results were attributed to low extracellular polymeric substance (EPS) content. However, further research is needed to better quantify EPS and determine the effect of HRAS operating parameters on EPS production. Overall the A/B pilot study was able to capture 47% of the influent COD as waste sludge while only oxidizing 45% of the influent COD. Of the COD captured, the A-stage contributed over 70% as dry solids. Coupled with high sludge production, VSR, and methane yield the A/B process was able to generate 10-20% more biogas and 10-20% less dry solids after anaerobic digestion than a comparable single-sludge BNR process.
Ph. D.

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37

Carriot, Nathan. "Caractérisation de la production métabolique de biofilms marins. : Vers une application à l'étude de biofilms complexes in situ". Electronic Thesis or Diss., Toulon, 2022. http://www.theses.fr/2022TOUL0001.

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Le phénomène de biofouling est un processus naturel qui impacte toutes les surfaces immergées en milieu marin engendrant des problèmes économiques et écologiques majeurs à l’échelle planétaire. Il est notamment induit par la formation de biofilms marins correspondant à la colonisation des surfaces immergées par des bactéries s’organisant en communautés en s’entourant d’une matrice de substances polymériques extracellulaires (EPS). L’objectif de ce travail est l’utilisation et le développement de méthodologies permettant l’étude et la compréhension de l’étape précurseur de ce phénomène. La corrélation des données récoltées à partir des méthodes appliquées (métabolomique et réseau moléculaire, protéomique, dosages colorimétriques, microscopies, spectroscopies) permet une approche multi-échelles pour la caractérisation des biofilms. Ces développements visent, en premier lieu, à caractériser la production biochimique globale de biofilms in vitro pour ensuite analyser des biofilms naturels formés in situ. L’utilisation de ce large panel de techniques a permis de répondre à certaines questions scientifiques comme l’impact des nutriments (phosphates), d’une enzyme (quorum sensing) ou de l’hydrodynamisme sur la nature de biofilms formés
The phenomenon of biofouling is a natural process that impacts all the surfaces submerged in the marine environment, generating major economic and ecological problems on a global scale. It is induced by the formation of marine biofilms corresponding to the colonization of submerged surfaces by bacteria organizing in communities by surrounding themselves with a matrix of extracellular polymeric substances (EPS). The objective of this work is the use and development of methodologies to study and understand the precursor stage of this phenomenon. The correlation of the data collected from the applied methods (metabolomics and molecular network, proteomics, colorimetric assays, microscopies, spectroscopy) allows a multi-scale approach for the characterization of biofilms. These developments aim, first of all, to characterize the overall biochemical production of in vitro biofilms and then analyse natural biofilms formed in situ. The use of this wide range of techniques has made it possible to answer certain scientific questions such as the impact of nutrients (phosphates), an enzyme (quorum sensing) or hydrodynamics on the nature of formed biofilms

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38

Brian-Jaisson, Florence. "Identification et caractérisation des exopolymères de biofilms de bactéries marines". Electronic Thesis or Diss., Toulon, 2014. http://www.theses.fr/2014TOUL0003.

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Dans l’environnement marin, les surfaces artificielles sont rapidement colonisées par des bactéries qui s’organisent en communautés appelées biofilms, s’entourant d’une matrice de substances polymériques extracellulaires (EPS). La formation d’un biofilm est une étape critique du processus nommé biofouling, c’est-à-dire l’accumulation de micro- et de macro-organismes sur une surface immergée, pouvant conduire à des conséquences néfastes dans le secteur marin. Dans cette étude, il s’agit d’identifier des souches bactériennes isolées de supports immergés en Mer Méditerranée et de les caractériser phénotypiquement par diverses approches. Leur capacité à former un biofilm in vitro a été évaluée dans différentes conditions avec une attention particulière portée sur leurs capacités à produire une matrice polymérique abondante riche en polysaccharides; l’objectif étant d’isoler des exopolysaccharides originaux à activité antifouling. Treize souches ont ainsi fait l’objet d’analyses phylogénétiques et d’une caractérisation phénotypique. Sept genres et douze espèces différentes ont été identifiés au sein desquelles deux isolats peuvent être affiliés à une nouvelle espèce, nommée Persicivirga mediterranea. Ce genre n’a jamais été décrit en Mer Méditerranée jusqu’à présent. L’extraction des EPS de chaque souche cultivée en biofilm a permis de déterminer leur composition générale en glucides, protéines, acides nucléiques et lipides. Une souche, Pseudoalteromonas ulvae TC14, se distingue par sa capacité à produire des exopolysaccharides en quantité importante. Il s’agit essentiellement de polymères du glucose dont les analyses chromatographiques et spectroscopiques ont révélé la diversité de taille (Mw ~ 1–4000 kDa), de charge (neutre ou anionique) et de fonction associée (lactate ou acétate). Les fractions d’EPS enrichies en polysaccharides inhibent la formation de biofilm par d’autres souches marines. Ces derniers sont également synthétisés par les bactéries en culture planctonique mais en proportions très différentes
In marine environment, artificial surfaces are promptly colonized by biofilms, which are communities of bacteria surrounded by matrix of extracellular polymeric substances (EPS). Formation of biofilm is a critical step of biofouling development, which corresponds to the accumulation of micro and macro-organisms on immersed surfaces and which can have important negative ramifications in particular in the marine sector. In this study, bacteria isolated from the Mediterranean Sea have been identified and characterized using different phenotypical tools. Their capacity to form a biofilm in vitro has been studied in different conditions, with a particular focus on their ability to produce abundant carbohydrate-rich EPS, the overall objective of the study being the isolation of original antifouling-active exopolysaccharides. Thirteen strains have been phylogenetically and phenotypically characterized. Seven genera and twelve species were identified among which two isolates were affiliated to a new species, named Persicivirga mediterranea. This genus has never been described in the Mediterranean Sea. Extraction of EPS of each strain, grown in biofilm conditions, allowed the determination of their general composition in carbohydrates, proteins, nucleic acids and lipids. One strain, Pseudoalteromonas ulvae TC14, was able to produce large quantities of exopolysaccharides, comprising in majority polymers of glucose whose chromatographic and spectroscopic analyzes revealed a diversity in size (Mw ~ 1-4000 kDa), charge (neutral or anionic) and associated function (acetate or lactate). These polysaccharides inhibited biofilm formed by other marine strains isolated from the Mediterranean Sea. They can also be synthesized by planktonic TC14, but in very different proportions

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39

Ersan, Yusuf Cagatay. "The Effects Of Seed Sludge Type And Anoxic/aerobic Period Sequence On Aerobic Granulation And Cod, N Treatment Performance". Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615330/index.pdf.

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The aim of this master thesis study was improvement of the required operational conditions for aerobic granulation in sequencing batch reactors (SBRs). In the first part of the study, membrane bioreactor sludge (MBS) and conventional activated sludge (CAS), were used to investigate the effect of suspended seed sludge type on granulation in SBRs. The MBS granules were found to be advantageous in terms of size, resistance to toxic effects, stability and recovery compared to CAS granules. During non-inhibitory conditions, sCOD removal efficiencies were 70±
13% and 67±
11% for MBS and CAS, and total nitrogen (TN) removal efficiencies were 38±
8% and 26±
8%, respectively. In the second part of the study, the effects of period sequence (anoxic-aerobic and aerobic-anoxic) on aerobic granulation from MBS, and sCOD, N removal efficiencies were investigated. Granules developed in anoxic-aerobic period sequence were more stable and larger (1.8-3.5 mm) than granules developed in aerobic-anoxic sequence. Under steady conditions, almost 95% sCOD, 90% Total Ammonia Nitrogen (TAN) and around 39-47 % of TN removal was achieved. Almost 100% denitrification in anoxic period was achieved in anoxic-aerobic period sequence and it was observed around 40% in aerobic-anoxic period sequence. The effects of influent sulfate (from 35.1 mg/L to 70.2 mg/L) on treatment efficiencies of aerobic granules were also investigated. The influent SO42- concentrations of 52.6 mg/L to 70.2 mg/L promoted sulfate reduction. The produced sulfide (0.24 mg/L to 0.62 mg/L) inhibited the ammonia-oxidizing bacteria (AOB) performance by 10 to 50%.

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40

Coburn, Kimberly Mary. "Effects of Extracellular Polymeric Substance Composition on Bacteria Disinfection by Monochloramine". University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1353016531.

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41

Verneuil, Laurent. "Toxicité environnementale et écotoxicité de nanotubes de carbone chez des diatomées benthiques : de la cellule au biofilm". Thesis, Toulouse, INPT, 2015. http://www.theses.fr/2015INPT0006/document.

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Différents effets de nanotubes de carbone (NTC) sur des diatomées benthiques ont été évalués via des approches microscopiques et biochimiques. Il a été montré que la structure du frustule, paroi silicifiée propre aux diatomées, est déterminante sur l'entrée ou non des NTC dans les cellules. Une internalisation des NTC dans la cellule a conduit à des effets génotoxiques et tératogènes. L'interaction des NTC avec les substances polymériques extracellulaires (SPE) produites par les diatomées a aussi été évaluée. Les SPE ont favorisé l'agglomération des NTC entre eux, ainsi que leur isolement physico-chimique vis-à-vis des diatomées. Une réponse des diatomées à la présence des NTC par la surproduction de SPE explique partiellement le retard de croissance observé. De plus, Des interactions entre SPE et NTC, majoritairement hydrophobes, ont été révélées. Ces interactions ont permis de réduire considérablement les effets des NTC sur les diatomées au cours du temps
Various effects of carbon nanotubes (CNTs) on benthic diatoms were assessed via microscopic and biochemical approaches. It has been shown that the structure of the specific to diatoms silicified frustule has a key role in the entry or not of CNTs into the cells. Moreover, Internalization of CNTs in the cell led to genotoxic and teratogenic effects. The interaction of the CNTs with the extracellular polymeric substances (EPS) produced by diatoms was also evaluated. EPS favored agglomeration of CNTs between them as well as their physico-chemical isolation for diatoms. A response of diatoms in the presence of CNTs by the overproduction of EPS partially explains the observed growth retardation. In addition, interactions between the EPS and CNTs, mainly hydrophobic, have been revealed. These interactions significantly reduced the effects of CNTs in diatoms over time

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42

Frías, Seoane Alina. "Caracterización estructural de bacterias antárticas adaptadas al frío y detección de nuevos emulsionantes: estudio de la cepa "Shewanella vesiculosa M7(T)”". Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/85406.

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Esta memoria doctoral forma parte del proyecto financiado por el Ministerio de Ciencia e Innovación (CICYT, CTQ2010-21183-C02-01), el cual tiene entre sus objetivos la búsqueda de nuevas cepas con capacidad para producir emulsionantes naturales poliméricos. Existe un interés real en el aislamiento y caracterización estructural y funcional de nuevos exopolímeros (EPS) obtenidos a partir de microorganismos de ambientes extremos que pudieran ser utilizados con estos fines en diversas industrias. Para ello, se realizó en primer lugar el estudio de los EPS desde el punto de vista ultraestructural, de cepas antárticas adaptadas al frío, mediante técnicas de microscopía electrónica de transmisión (MET) después de procesar las muestras por criofijación a alta presión seguida de criosustitución (HPF-FS). Estas técnicas aportaron numerosos detalles sobre la ultraestructura de las distintas cepas y el material extracelular que producen, al lograr preservar el material biológico próximo a su estado natural. Se observó que este material polimérico extracelular es para la mayoría de las cepas complejo con la presencia de material capsular alrededor de las células y abundantes estructuras vesiculares dispersas en la matriz extracelular secretada por las bacterias. Es la primera vez que se describen y visualizan de manera tan clara y abundante las vesículas de membrana externa (VME) que producen bacterias no patógenas de ambientes naturales antárticos. De igual forma, es la primera vez que se reporta la presencia de estas estructuras en cepas de los géneros Marinobacter y Psychrobacter. Asimismo, se estudió el origen de las proteínas presentes en las VME mediante geles SDS-PAGE donde se mostraron los perfiles proteicos comparados con las proteínas de membrana externa. Esto evidenció el origen de estas VME formadas a partir de esta membrana, al presentar proteínas en la fracción de VME, que comigraron con proteínas que estaban presentes en la fracción de membrana externa, además en el perfil proteico de la membrana externa se detectaron proteínas adicionales que no estaban presentes en VME. Se estudió la influencia de la temperatura sobre la producción y morfología de VME producidas en la cepa S. livingstonensis NF22T Para esta bacteria psicrotolerante se demostró que la temperatura influye en la producción de VME. A bajas temperaturas la cantidad de VME que produce la cepa es mayor, su tamaño es menor y más regular y el perfil electroforético muestra la expresión diferencial de algunas proteínas, viéndose sobrexpresadas proteínas relacionadas con funciones de transporte a nivel de membrana. Se realizaron análisis proteómicos para identificar las proteínas presentes en las VME producidas a 4 y 16 ºC a partir de S. livingstonensis NF22T y S. vesiculosa M7T. Para ambas cepas se identificaron fundamentalmente proteínas de membrana externa y periplasmáticas con diferentes funciones fisiológicas, destacando por su abundancia las proteínas implicadas en el transporte y metabolismo de iones inorgánicos así como las relacionadas en la biogénesis de las envueltas celulares. El material extracelular (EPS) obtenido y purificado a partir de Shewanella vesiculosa M7T presentó mayor actividad emulsionante frente a aceites comestibles que los emulsionantes comercializados goma arábiga y xantano y su caracterización reveló que contiene abundantes VME y polímeros polisacarídicos, siendo sus componentes químicos mayoritarios azúcares neutros y aminados, lípidos de membrana y aminoácidos.
The present work is part of the research project (CICYT, CTQ2010-21183-C02-01), which has among its objectives the search for new strains capable to produce natural polymeric emulsifiers. There is a real interest in the isolation and structural and functional characterization of new exopolymers (EPS) derived from microorganisms of extreme environments that could be used for these purposes in various industries. Many Gram-negative, cold-adapted bacteria from the Antarctic environment produce large amounts of extracellular matter, which has potential biotechnology applications. We examined the ultrastructure of extracellular matter from Antarctic bacteria by transmission electronic microscopy after high pressure freezing and freeze substitution. All analyzed extracellular matter appeared as a netlike mesh composed of a capsular polymer around cells and large numbers of outer membrane vesicles (OMV), which have not been described for members of the genera Psychrobacter and Marinobacter so far. OMV showed the typical characteristics described for these structures, and seemed to be surrounded by the same capsular polymer as that found around cells. The analysis of OMV proteins from Antarctic strains by SDS-PAGE showed different banding profiles in OMV compared to the outer membrane, suggesting some kind of protein sorting during membrane vesicle formation. For the psychrotolerant bacterium, S. livingstonensis NF22T, the growth temperature seemed to influence the amount and morphology of OMV. In an initial attempt to elucidate the functions of OMV from S. livingstonensis NF22T and S. vesiculosa M7T we conducted a proteomic analysis on membrane vesicles obtained at 4 and 16°C. At both temperatures, OMV were highly enriched in outer membrane proteins and periplasmic proteins related to nutrient processing and transport in Gram-negative bacteria, suggesting that OMV could be related with nutrient sensing and bacterial survival. Differences were observed in the expression of some proteins depending on incubation temperature but further studies will be necessary to define their roles and implications in the survival of bacteria in the extreme Antarctic environment. The extracellular material (EPS) obtained and purified from Shewanella vesiculosa M7T had a higher emulsifying activity against edible oils than commercial emulsifiers like arabic and xanthan gums. Characterization of this EPS revealed that it contains abundant OMV and polysaccharides polymers, with neutral and amino sugars, membrane lipids and aminoacids as its major chemical components.

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43

Redmile-Gordon, Marc. "Investigating the functional potential of microbial extracellular polymer substances (EPS) in agricultural soils". Thesis, University of Bristol, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616636.

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Most microbial life on earth exists as a collective entities, or 'biofilms'. These biofilms consist of the microbial cells and the extracellular biopolymers (EPS) they exude. The EPS serve many purposes of benefit to the microorganisms, but whereas EPS have received much attention in medical sciences, the science of EPS in soil is relatively undeveloped. Adding EPS to porous media (such as sand or soil) can' improve water-retention which is of great potential benefit to agriculture. ,It is not cost-effective to do this directly however due to the cost of deployment and physical incorporation with soil. Therefore it is more useful to identify managements that increase EPS indirectly using microbes already present in soil. These managements cannot be identified without the use of appropriate and meaningful analytical techniques that characterise the EPS produced by the soil microbial community. ' A range of extraction methods and measurements were compared, with the most representative selected to investigate i) triggers to EPS production ii) interplay between soil-nitrogen and carbon dynamics, and ii) the impact of EPS upon aggregate stability. Ultimately, an extraction method using cation exchange resin was selected. This method appeared to maintain membrane integrity of the majority of cells, thus minimising the likelihood of contaminating the EPS extracts with intracellular material. Using this method, EPS production in soil was shown to be affected by substrate availability, C:N ratio, hydrology, zinc contamination, and the nature of carbon substrates provided:1 Finally, the protein content of EPS was found to be closely related to aggregate stability, which in turn maintains soil functions critical to ecosystem services and agricultural productivity. This thesis represents a step towards understanding soil-native-EPS production: towards applied goals (such as improving soil water retention and understanding the consequences of agricultural managements) and advancing our fundamental knowledge of soil organic matter dynamics

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44

Pierre, Guillaume. "Caractérisation biochimique d’exopolymères d’origine algale du bassin de Marennes-Oléron et étude des propriétés physico-chimiques de surface de micro-organismes impliquées dans leur adhésion". Thesis, La Rochelle, 2010. http://www.theses.fr/2010LAROS314/document.

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Le principal objectif de cette thèse était de mieux comprendre l’importance des Substances Polymériques Extracellulaires (SPE) dans la structuration et la formation des biofilms benthiques ; tout en s’inscrivant dans une étude plus globale des mécanismes écologiques impliqués dans le fonctionnement des vasières intertidales. La mise au point des dosages biochimiques a été effectuée sur le mucilage de l’algue Chaetomorpha aerea et a permis en parallèle de purifier un polysaccharide sulfaté riche en galactose, présentant une activité bactéricide sélective contre la souche Staphylococcus aureus (ATCC 25923). Les études biochimiques et écologiques menées sur les SPE extraits de la vasière charentaise ont ensuite permis de quantifier leur dynamique de production et leur composition, en fonction des conditions environnementales. La présence de désoxy-sucres et d’acides uroniques au sein des SPE capsulaires a laissé supposer que ces fractions jouaient un rôle important dans la formation et le devenir du biofilm microphytobenthique. La dernière partie des travaux a permis de caractériser les propriétés acide/base de Lewis et hydrophile/hydrophobe de la surface de la micro-algue Navicula jeffreyi, impliquée dans la formation de biofilms benthiques, par des méthodes classiques d’analyse. L’utilisation d’une nouvelle méthode, la Chromatographie Gazeuse Inverse (CGI), a permis d’obtenir des résultats intéressants et relativement similaires, confirmant le caractère prometteur de la CGI pour l’étude des propriétés de surface des micro-organismes
The main goal of this thesis was to better understand the importance of Extracellular Polymeric Substances (EPS) in the structuring and formation of benthic biofilms; while considering a global conception of the ecological mechanisms involved in the functioning of intertidal mudflats. The development of the biochemical assays was done on the mucilage of the macroalgae Chaetomorpha aerea and allowed purifying a polysaccharide rich in galactose, showing a selective bactericidal activity against Staphylococcus aureus (ATCC 25923). Then, the biochemical and ecological studies concerning the EPS extracted from the local mudflat allowed studying their dynamic of production and composition in relation to environmental conditions. The presence of deoxy sugars and uronic acids in the bound EPS highlighted their important roles during the formation and the life of microphytobenthic biofilms. The last part of the work was used to characterize the acid/base of Lewis and hydrophilic/hydrophobic surface properties of the microalgae Navicula jeffreyi, involved in the formation of benthic biofilms, by using classical analysis methods. The use of a new method, named Inverse Gas Chromatography (IGC), allowed getting interesting and relatively similar results, confirming the potential of the method to study the surface properties of microorganisms

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45

De, Crignis Margot. "Déterminisme de la production bactérienne dans les vasières intertidales du Bassin de Marennes-Oléron : rôle des exopolysaccharides". Phd thesis, Université de La Rochelle, 2010. http://tel.archives-ouvertes.fr/tel-00605659.

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Les vasières intertidales sont le siège d'une forte production primaire sous la forme d'un biofilmmicrophytobenthique qui se développe en surface à marée basse. Ce biofilm se compose principalement de diatomées et de bactéries hétérotrophes. Ces deux composantes sécrètent des substances polymériques extracellulaires (EPS) qui jouent différents rôles dans le biofilm. Le travail présenté s'est basé sur différentes échelles d'observation (in situ à 2 saisons, mésocosme en laboratoire, et échelle fine du biofilm en microscopie confocale) et a permis de mettre en évidence les interactions des diatomées et des bactéries à différents moments de la marée et du nycthémère. L'utilisation d'une nouvelle méthode d'extraction des EPS a permis d'éclaircir leur rôle en évitant les contaminations par les substances internes provoquées par les méthodes classiques. Les EPS colloïdales particulièrement riches en glucose s'associent au déplacement des diatomées, notamment lors d'un stress (sursalure, carence en nutriments) et sont préférentiellement consommées par les bactéries, après leur dégradation par les enzymes ou leur hydrolyse dans l'eau interstitielle. Les EPS liées au frustule, et plus particulièrement les sucres, inhiberaient le développement bactérien à proximité de la cellule algale. Elles sont surtout sécrétées lors de la mise en place du biofilm et pour protéger la cellule quand les conditions sont osmotiquement défavorables et leur richesse en protéine leur confère un potentiel intéressant pour les bactéries qui peuvent les utiliser comme substrat azoté en cas de carence. D'autres substances ont été plutôt sécrétées parles bactéries telles que les N-acétylglucosamines et les protéines colloïdales de bas poids moléculaire,certainement des enzymes bactériennes, ainsi que le glucose qui semble être associé au EPS colloïdaux des diatomées mais aussi aux EPS bactériens selon l'analyse en microscopie confocale en utilisant des lectines comme marqueurs d'EPS.

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46

Takaidza, Samkeliso. "The effects of biofouling on a reverse osmosis membrane purification system at Sasol, Sasolburg". Thesis, Vaal University of Technology, 2011. http://hdl.handle.net/10352/452.

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M. Tech. (Biotechnology, Department of Biosciences, Faculty of Applied and Computer Sciences), Vaal University of Technology.
Reverse osmosis (RO) membranes are widely used in water purification. The presence of biofilms in water and industrial water purification systems is prevalent. As a result, biofouling which is a biofilm problem causes adverse effects on reverse osmosis process, which include flux decline, shorter membrane lifetime and an increase in energy consumption The effect of biofouling on RO membranes was investigated at a water treatment facility at Sasol, Sasolburg by investigating the quality of water purified by the RO system and the extent of fouling that is attributed to biofouling. Chemical and microbiological data was averaged based on the results obtained from water analysis and samples from a fouled membrane. Bacteriological plate counts ranged between log 1.5 to 4 cfu/ml in water samples and log 3.9 to 4.5 cfu/cm2 on biofilm from the membrane surface. Water analysis indicated a high conductivity of 121 µS/cm in the feed and 81 ppm of the TDS, whereas in the permeate conductivity was found to be around 6 µS/cm and 3.8 ppm of the TDS. This indicated that components present in the feed were retained by the membrane. This was supported by membrane autopsy which showed that the bacteria and elements found in the feedwater were also present on the membrane surface, hence contributing to fouling. An average of 33% of cellular ATP was measured on the biofilm from membrane sample, showing that the fouling bacteria are metabolically active in situ. The results clearly indicated that an important biological activity occurred at the membrane surface.

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47

Kuklinski, Andrzej [Verfasser], e Wolfgang [Akademischer Betreuer] Sand. "Development of extracellular polymeric substance-derived protective films against microbiologically influenced corrosion by Desulfovibrio vulgaris / Andrzej Kuklinski ; Betreuer: Wolfgang Sand". Duisburg, 2017. http://d-nb.info/1132510546/34.

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48

Nassar, David Aziz. "A Mathematical Model of Biofilm Growth and Decay". University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1239645901.

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49

Riera, Elisabeth. "Vers une construction raisonnée d’une nouvelle génération de récifs artificiels : Analyses comparatives des facteurs intrinsèques favorisant leur colonisation de la micro à la macro-échelle". Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4001.

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Les récifs artificiels sont des structures immergées posées délibérément sur le fond marin pour imiter certaines caractéristiques d’un habitat naturel, ils sont utilisés depuis des milliers d’années par les hommes dans le but d’améliorer leurs pratiques de pêches et depuis peu ils sont également employés pour la protection voire la restauration de certains habitats marins. Malgré ces divers objectifs, il réside encore un manque de fondements scientifiques pour déterminer la qualité de ces structures mises à l’eau afin d’en évaluer leur efficacité. Les présent travaux, focalisés sur l’étude de leurs caractéristiques intrinsèques, à savoir leurs matériaux et leurs structuresUn suivi conjugué du biofilm et du macrofouling sur différents substrats, complété par une analyse de leur contenu en métaux lourds a permis de mettre en évidence la qualité de certains substrats utilisé pour la construction de récifs artificiel. Le suivi simple du biofilm s’est révélé être un bon indicateur pour mettre en valeur ces différences de façon simple et rapide pour valider l’utilisation de tel ou tel substrat. Par ailleurs, la mise au point d’une méthode destinée à évaluer la complexité et l’hétérogénéité des récifs artificiels a permis de donner une classification pertinente des différentes structures existantes. Cette méthode standardisée permettra d’évaluer in situ l’influence des paramètres structuraux des récifs artificiels sur le recrutement, l’abondance, la distribution et/ou la diversité. Une première étude à l’échelle microscopique a permis de révéler l’influence de la structure du substrat à la fois sur l’abondance du biofilm et sur l’activité photosynthétique de ces communautés.L’ensemble de ces résultats permet d’offrir un cadre scientifique plus précis pour aborder la construction des récifs artificiels sur le choix de leurs matériaux et de leurs designs. De futures lignes directrices pourraient être émises afin d’optimiser l’efficacité de tout projet d’immersion de récifs artificiels
Artificial reefs are submerged structures deliberately placed on the seabed to mimic some characteristics of a natural habitat, they have been used for thousands of years by fishermen to improve their fishing practices and recently they are also used for the protection or even the restoration of certain marine habitats. Despite these various objectives, there is still a lack of scientific fundaments for determining the quality of these submerged structures in order to assess their effectiveness. The present works, focused on the study of their intrinsic characteristics, namely their materials and their structures. A combined monitoring of the biofilm and the macrofouling on different substrates, supplemented by an analysis of their heavy metal content allowed to highlight the quality of certain substrates used for the construction of artificial reefs. Simple monitoring of the biofilm has proven to be an efficient indicator for highlighting these differences to validate the use of a particular substrate.In addition, the development of a method to assess the complexity and heterogeneity of artificial reefs has enabled us to give a relevant classification of the various existing structures. This standardized method will allow to assess in situ the influence of structural parameters of artificial reefs on recruitment, abundance, distribution and/or diversity. A first study at the microscopic scale revealed the influence of substrate structure on both the abundance of biofilm and the photosynthetic activity of these communities.A more precise scientific framework is now available to guide the construction of artificial reefs on the choice of materials and the design of artificial reef structures in order to optimize the effectiveness of artificial reef immersion project

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50

Robles, Martínez Ángel. "Modelling, simulation and control of the filtration process in a submerged anaerobic membrane bioreactor treating urban wastewater". Doctoral thesis, Editorial Universitat Politècnica de València, 2013. http://hdl.handle.net/10251/34102.

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El reactor anaerobio de membranas sumergidas (SAnMBR) está considerado como tecnología candidata para mejorar la sostenibilidad en el sector de la depuración de aguas residuales, ampliando la aplicabilidad de la biotecnología anaerobia al tratamiento de aguas residuales de baja carga (v.g. agua residual urbana) o a condiciones medioambientales extremas (v.g. bajas temperaturas de operación). Esta tecnología alternativa de tratamiento de aguas residuales es más sostenible que las tecnologías aerobias actuales ya que el agua residual se transforma en una fuente renovable de energía y nutrientes, proporcionando además un recurso de agua reutilizable. SAnMBR no sólo presenta las principales ventajas de los reactores de membranas (i.e. efluente de alta calidad, y pocas necesidades de espacio), sino que también presenta las principales ventajas de los procesos anaerobios. En este sentido, la tecnología SAnMBR presenta una baja producción de fangos debido a la baja tasa de crecimiento de los microorganismos implicados en la degradación de la materia orgánica, presenta una baja demanda energética debido a la ausencia de aireación, y permite la generación de metano, el cual representa una fuente de energía renovable que mejora el balance energético neto del sistema. Cabe destacar el potencial de recuperación de nutrientes del agua residual bien cuando el efluente es destinado a irrigación directamente, o bien cuando debe ser tratado previamente mediante tecnologías de recuperación de nutrientes. El objetivo principal de esta tesis doctoral es evaluar la viabilidad de la tecnología SAnMBR como núcleo en el tratamiento de aguas residuales urbanas a temperatura ambiente. Por lo tanto, esta tesis se centra en las siguientes tareas: (1) implementación, calibración y puesta en marcha del sistema de instrumentación, control y automatización requerido; (2) identificación de los parámetros de operación clave que afectan al proceso de filtración; (3) modelación y simulación del proceso de filtración; y (4) desarrollo de estrategias de control para la optimización del proceso de filtración minimizando los costes de operación. En este trabajo de investigación se propone un sistema de instrumentación, control y automatización para SAnMBR, el cual fue esencial para alcanzar un comportamiento adecuado y estable del sistema frente a posibles perturbaciones. El comportamiento de las membranas fue comparable a sistemas MBR aerobios a escala industrial. Tras más de dos años de operación ininterrumpida, no se detectaron problemas significativos asociados al ensuciamiento irreversible de las membranas, incluso operando a elevadas concentraciones de sólidos en el licor mezcla (valores de hasta 25 g·L-1 ). En este trabajo se presenta un modelo de filtración (basado en el modelo de resistencias en serie) que permitió simular de forma adecuada el proceso de filtración. Por otra parte, se propone un control supervisor basado en un sistema experto que consiguió reducir el consumo energético asociado a la limpieza física de las membranas, un bajo porcentaje de tiempo destinado a la limpieza física respecto al total de operación, y, en general, un menor coste operacional del proceso de filtración. Esta tesis doctoral está integrada en un proyecto nacional de investigación, subvencionado por el Ministerio de Ciencia e Innovación (MICINN), con título ¿Modelación de la aplicación de la tecnología de membranas para la valorización energética de la materia orgánica del agua residual y la minimización de los fangos producidos¿ (MICINN, proyecto CTM2008-06809- C02-01/02). Para obtener resultados representativos que puedan ser extrapolados a plantas reales, esta tesis doctoral se ha llevado a cabo utilizando un sistema SAnMBR que incorpora módulos comerciales de membrana de fibra hueca. Además, esta planta es alimentada con el efluente del pre-tratamiento de la EDAR del Barranco del Carraixet (Valencia, España).
Robles Martínez, Á. (2013). Modelling, simulation and control of the filtration process in a submerged anaerobic membrane bioreactor treating urban wastewater [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34102
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