Thèses sur le sujet « Dissolved oxygen Dam removal »
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Zhang, Yiding. « Predicting River Aquatic Productivity and Dissolved Oxygen before and after Dam Removal in Central Ohio, USA ». The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337983076.
Texte intégralBa, Mouhamadoul Moustapha. « Dynamique des interactions physico-chimiques en zone hyporhéique : influence des crues et de la suppression des barrages ». Electronic Thesis or Diss., Université de Rennes (2023-....), 2023. http://www.theses.fr/2023URENB076.
Texte intégralIn the context of the Selune River in France, where two dams are currently being removed to restore hydro-sedimentary continuity in the river, this thesis aimed at understanding the potential impacts of these changes on the dynamics of the hyporheic zone. This zone, crucial for the reproduction of certain species and economic activities, requires in-depth monitoring. To achieve this, a network of autonomous sensors measuring various physicochemical variables was deployed starting in October 2021, for a duration of 2 years. The methodology of this study is based on the analysis of vertical physicochemical gradients in the riverbed sediments, focusing on oxygen and conductivity. The heterogeneity of permeability was also examined through measurements of electrical conductivity. The results revealed significant spatial variations in bed permeability. Specifically, the impact of sediment transport released by the dam removal was observed, causing a decrease in permeability in certain areas. Regarding dissolved oxygen, local variations were related to infiltration and exfiltration regimes, with temporary decreases due to microbial activity in response to organic matter input. Furthermore, the arrival of sediments in May 2022 led to an extended period of anoxia, with potentially significant consequences for aquatic fauna. This research has contributed to a better understanding of the hyporheic zone and emphasized the significant impact of sediment transport on permeability, oxygen dynamics, and clogging phenomena. It has also opened new perspectives for the analysis of hydrothermal properties of the riverbed, water flow, and the use of electrical conductivity measurements to estimate the depth of groundwater-river exchanges, as well as the development of theoretical models to predict the transport and degradation of dissolved elements
Beck, Jason Lee. « Optimization of Biological Nitrogen Removal From Fermented Dairy Manure Using Low Levels of Dissolved Oxygen ». Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/35593.
Texte intégralMaster of Science
楊龍元 et Lung-yuen Christopher Yeong. « Removal of wastewater cod and nitrogen using fibrous packing media ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1991. http://hub.hku.hk/bib/B31210636.
Texte intégralOwusu-Agyeman, Isaac. « Systems for ammonium concentration for further removal in the partial nitritation/anammox technology ». Thesis, KTH, VA-teknik, Vatten, Avlopp och Avfall, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99356.
Texte intégralNair, Arthur William. « Investigation of the Effects of Sequential Anaerobic, Anoxic and Aerobic Zones on Dissolved Oxygen Transfer Parameters in a biological Nutrient Removal Pilot Plant ». Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/46264.
Texte intégralMaster of Science
Petre, Catalin Florin. « Alkaline oxidation of hydrosulfide and methyl mercaptide by iron/cerium oxide-hydroxide in presence of dissolved oxygen. Possible application for removal of Total Reduced Sulfur (TRS) emissions in the Pulp & ; Paper industry ». Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24330/24330.pdf.
Texte intégralHydrogen sulfide (H2S) and methyl mercaptan (MM) are the most abundant odor contaminants among the Total Reduced Sulfur (TRS) quartet (H2S, CH3SH, (CH3)2S, (CH3)2S2) contained in the Kraft mill atmospheric emissions. The association of TRS with sufficient oxygen could be taken advantage of, based on the iron chemistry, to convert TRS gases to odorless non-volatile products. The process uses Fe/Ce oxide-hydroxide (Fe/CeOx) slurried in alkaline solutions where both H2S and MM oxidative absorption (in the form of hydrosulfide and methyl mercaptide) is promoted. Capillary electrophoresis protocols were developed for the separation, identification and quantification of hydrosulfide, methyl mercaptide, polysulfides, thiosulfate, sulfate, sulfite and tetrathionate. The kinetics and mechanism of the anoxic reaction between hydrosulfide and Fe/CeOx were studied for pH [8.0-11.0] in a batch slurry reactor. Most of Fe(II) produced at pH = 9.5 remained associated with the oxide surface in the time-frame of the experiments. Hydrosulfide was converted into polysulfides, thiosulfate and, probably, elemental sulfur, while the leached Fe2+ and thiosulfate dovetailed equimolarly. A detailed reaction pathway of the anoxic oxidation of hydrosulfide by Fe/CeOx was proposed for explaining the formation of above products and whereof a kinetic model was derived to depict the Fe2+ leaching and hydrosulfide consumption rates. In oxic conditions at pH [8.5-11.0], Fe/CeOx will oxidize hydrosulfide via a combined heterogeneous-homogenous pathway to yield the same products as in anoxia. Oxygen enhanced Fe/CeOx-promoted hydrosulfide oxidation by more than a factor three when compared with anoxic reaction. Oxygen is believed to have a double role: first, it re-oxidizes iron from Fe(II) to Fe(III); second, it promotes oxidation of hydrosulfide to polysulfides which in turn transforms into non-volatile, non-odorous thiosulfate. The reaction between methyl mercaptide and Fe/CeOx was studied at different pH values [10.5-12] both in anoxic and oxic conditions. Up to 100% conversions of mercaptide were obtained in oxic conditions, though the mercaptide conversion was found to be tributary to the dissolved oxygen. Interference with hydrosulfide co-mixed with mercaptide caused an inhibition in the conversion for both pollutants, due to the incipient polysulfides formation. The oxidation of methyl mercaptide by the Fe/CeOx/O2 system did not affect the re-oxidative regeneration of surface Fe(III) by O2. Fe/CeOx appears to be a very promising material for a redox-scrubbing process targeting the TRS emissions from Kraft mills, via in situ regeneration of Fe(III) sites by O2.
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Petre, Cătălin Florin. « Alkaline oxidation of hydrosulfide and methyl mercaptide by iron/cerium oxide-hydroxide in presence of dissolved oxygen : possible application for removal of Total Reduced Sulfur (TRS) emissions in the Pulp & ; Paper industry ». Doctoral thesis, Université Laval, 2007. http://hdl.handle.net/20.500.11794/19640.
Texte intégralLe sulfure d'hydrogène (H2S) et le méthyle-mercaptan (MM) sont les contaminants odorants les plus abondants parmi le quatuor qui compose les soufres réduits totaux (SRT) (H2S, CH3SH, (CH3)2S, (CH3)2S2) dans les émissions atmosphériques des industries papetières Kraft. L'association de SRT avec suffisamment d'oxygène peut être exploitée sur la base de la chimie du fer, pour convertir les SRT gazeux en produits non-volatils et non-odorants. Le procédé utilise l'oxyde-hydroxyde de Fe/Ce (Fe/CeOx) dans des solutions alcalines où l'absorption oxydative de H2S et de MM (sous forme d’ hydrosulfure et de méthyle mercapture) est favorisée. Des protocoles d'électrophorèse capillaire ont été développés pour la séparation, l'identification et la quantification de l’hydrosulfure, du méthyle mercapture, des polysulfures, du thiosulfate, du sulfate, du sulfite et du tétrathionate. La cinétique et le mécanisme de la réaction anoxique entre l’hydrosulfure et le Fe/CeOx ont été étudiés aux pH [8.0-11.0] dans un réacteur batch liquide-solide. La plupart du Fe(II) produit à pH = 9.5 reste associée à la surface de l'oxyde dans l’échelle de temps des expériences. L’hydrosulfure a été converti en thiosulfate, polysulfures et, probablement, en soufre élémentaire, alors que le Fe2+ lixivié et le thiosulfate ont montré une production équimolaire pour pH ≥ 9.5. Un mécanisme de réaction détaillé pour l'oxydation anoxique d’hydrosulfure par le Fe/CeOx a été proposé pour expliquer la formation des produits ci-dessus et dont un modèle cinétique a été dérivé pour décrire les vitesses de lixiviation du Fe(II) et de consommation d’hydrosulfure. En conditions oxiques à pH [8.5-11.0], le Fe/CeOx oxyde l’hydrosulfure via une voie combinée hétérogène-homogène pour former les mêmes produits qu’en anoxique. L'oxygène accélère l'oxydation de l’hydrosulfure par le Fe/CeOx par un facteur de plus de trois en comparaison avec la réaction anoxique. L'oxygène assume un double rôle : d'abord, il ré-oxyde le fer de Fe(II) à Fe(III); en second lieu, il favorise l'oxydation de l`hydrosulfure vers les polysulfures et de ces-ci vers le thiosulfate, un produit non-volatile et non-odorant. L'oxydation du méthyle mercapture par Fe/CeOx a été étudiée aux différentes valeurs du pH [10.5-12] en conditions anoxique et oxique. Des conversions de mercapture allant jusqu'à 100% ont été obtenues en conditions oxiques bien que la conversion du mercapture se soit avérée tributaire de la quantité d'oxygène dissous. L'interférence avec l’hydrosulfure co-mélangé avec le mercapture a causé une inhibition dans la conversion des deux polluants. Une telle inhibition est due aux polysulfures naissants formés par l'oxydation de l’hydrosulfure. L'oxydation du méthyle mercapture par le système Fe/CeOx/O2 n'a pas affecté la capacité de régénération du Fe(III) de surface par l'oxygène dissous. Fe/CeOx semble être un matériau très prometteur pour un éventuel procédé de lavage-oxydatif pour l’élimination du méthyle mercaptan dans les émissions des industries papetières de type Kraft.
Hydrogen sulfide (H2S) and methyl mercaptan (MM) are the most abundant odor contaminants among the Total Reduced Sulfur (TRS) quartet (H2S, CH3SH, (CH3)2S, (CH3)2S2) contained in the Kraft mill atmospheric emissions. The association of TRS with sufficient oxygen could be taken advantage of, based on the iron chemistry, to convert TRS gases to odorless non-volatile products. The process uses Fe/Ce oxide-hydroxide (Fe/CeOx) slurried in alkaline solutions where both H2S and MM oxidative absorption (in the form of hydrosulfide and methyl mercaptide) is promoted. Capillary electrophoresis protocols were developed for the separation, identification and quantification of hydrosulfide, methyl mercaptide, polysulfides, thiosulfate, sulfate, sulfite and tetrathionate. The kinetics and mechanism of the anoxic reaction between hydrosulfide and Fe/CeOx were studied for pH [8.0-11.0] in a batch slurry reactor. Most of Fe(II) produced at pH = 9.5 remained associated with the oxide surface in the time-frame of the experiments. Hydrosulfide was converted into polysulfides, thiosulfate and, probably, elemental sulfur, while the leached Fe2+ and thiosulfate dovetailed equimolarly. A detailed reaction pathway of the anoxic oxidation of hydrosulfide by Fe/CeOx was proposed for explaining the formation of above products and whereof a kinetic model was derived to depict the Fe2+ leaching and hydrosulfide consumption rates. In oxic conditions at pH [8.5-11.0], Fe/CeOx will oxidize hydrosulfide via a combined heterogeneous-homogenous pathway to yield the same products as in anoxia. Oxygen enhanced Fe/CeOx-promoted hydrosulfide oxidation by more than a factor three when compared with anoxic reaction. Oxygen is believed to have a double role: first, it re-oxidizes iron from Fe(II) to Fe(III); second, it promotes oxidation of hydrosulfide to polysulfides which in turn transforms into non-volatile, non-odorous thiosulfate. The reaction between methyl mercaptide and Fe/CeOx was studied at different pH values [10.5-12] both in anoxic and oxic conditions. Up to 100% conversions of mercaptide were obtained in oxic conditions, though the mercaptide conversion was found to be tributary to the dissolved oxygen. Interference with hydrosulfide co-mixed with mercaptide caused an inhibition in the conversion for both pollutants, due to the incipient polysulfides formation. The oxidation of methyl mercaptide by the Fe/CeOx/O2 system did not affect the re-oxidative regeneration of surface Fe(III) by O2. Fe/CeOx appears to be a very promising material for a redox-scrubbing process targeting the TRS emissions from Kraft mills, via in situ regeneration of Fe(III) sites by O2.
Oliveira, Pedro Henrique da Silva. « Influ?ncia da intensidade de aera??o na forma??o do floco de lodo ativado e na efici?ncia de remo??o de mat?ria org?nica ». Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15858.
Texte intégralCoordena??o de Aperfei?oamento de Pessoal de N?vel Superior
In wastewater treatment, activated sludge systems have been a technology widely applied as secondary treatment. During this step, which has a strong biological aspect, it is necessary to introduce oxygen supply for the maintenance of metabolic activity of the bacteria through the aerators. Aeration devices are responsible for most of the energy consumption in this stage. In this background, the influence of three aeration intensities (atmospheric air flow 3.5, 7.0 and 10.5 L.min-1) and the concentration of dissolved oxygen (DO) on the dimension of activated sludge flocs as well as on the efficiency of organic matter removal were assessed using a traditional activated sludge system which was fed with synthetic domestic wastewater. Samples were taken weekly from the three units that make up the system feed, aeration and storage tank in order to verify the Chemical Oxygen Demand (COD). It was established the process efficiency through a comparison between the initial and final COD. Besides the parameters already mentioned, this monitoring work on activated sludge batch system was also observed by Mixed Liquor Suspend Solids (MLSS), Volatile Suspend Solids (VSS), pH and temperature measures. The results have showed a maximum removal efficiency around 75% in the first aeration sequence and approximately 85% for the second and third one. For the first aeration, the DO concentration remained higher than 3.0 mg.L-1 and a diameter range from 10 to 60 μm was observed. In the second e third sequence, the DO concentration remained higher than 4.0 mg.L-1 with a diameter range of 10 until 200 μm. Although the sequence 1 and 2 have presented similar performances for organic matter removal, the sequence 2 promoted a regular floc size distribution and with lower values of Sludge Volumetric Index (SVI) meaning a better flocculating ability. In addition, the results reaffirmed what the literature has reported: higher DO concentrations produce flocs with greater dimensions
No tratamento de ?guas residu?rias, os sistemas de lodos ativados t?m sido uma tecnologia largamente aplicada como tratamento secund?rio. Durante essa etapa, a qual possui uma caracter?stica fortemente biol?gica, ? necess?rio o fornecimento de oxig?nio para a manuten??o da atividade metab?lica das bact?rias atrav?s de aeradores. Os dispositivos de aera??o s?o respons?veis pela maior parte do consumo de energia ao longo dessa fase. Nesse contexto, a influ?ncia de tr?s intensidades de aera??o (vaz?o de ar atmosf?rico de 3,5, 7,0 e 10, 5 L.min-1) e a concentra??o de oxig?nio dissolvido (OD) sobre a dimens?o de flocos de lodo ativado, e bem como sobre a efici?ncia de remo??o foram avaliadas utilizando um sistema tradicional de lodos ativados alimentado com efluente dom?stico sint?tico. Amostras foram retiradas semanalmente das tr?s unidades que compunham o sistema tanque de alimenta??o, de aera??o e de armazenamento para verificar a Demanda Qu?mica de Oxig?nio (DQO). A efici?ncia do processo foi estabelecida atrav?s da compara??o entre a DQO inicial e final. Al?m dos par?metros j? mencionados, este trabalho de monitoramento do sistema de lodos ativados de bancada foi observado tamb?m por meio de medi??es de S?lidos em Suspens?o Totais (SST) e Vol?teis (SSV), pH e temperatura. Os resultados mostraram uma efici?ncia m?xima de remo??o de quase 75% na primeira sequ?ncia de aera??o e aproximadamente 85% para a segunda e terceira sequ?ncias. Para a primeira aera??o, a concentra??o de OD manteve-se maior que 3,0 mg.L-1 e uma faixa de di?metro de 10 a 60 μm foi observada, enquanto que na segunda e terceira sequ?ncia, a concentra??o de OD permaneceu superior a 4,0 mg.L-1 com uma faixa de di?metro de 10 a 200 μm. Embora a sequ?ncia 2 e 3 tenham apresentado, ambas, desempenhos similares para remo??o de mat?ria org?nica, a sequ?ncia 3 promoveu uma distribui??o de tamanho de flocos mais regular e com baixos valores de ?ndices Volum?tricos do Lodo (IVL), configurando em uma melhor habilidade de sedimenta??o. Em adi??o, os resultados reafirmam o que literatura tem relatado, maiores concentra??es de OD produzem flocos com maiores dimens?es
Селянина, Т. В., et T. V. Selyanina. « Количественное определение натриевой соли 2-этилтио-6-нитро-1,2,4-триазоло-[5,1-c]-1,2,4-триазин-7-она дигидрата методом вольтамперометрии : магистерская диссертация ». Master's thesis, б. и, 2020. http://hdl.handle.net/10995/94625.
Texte intégralThe object of the study was the substance 2-ethylthio-6-nitro-1,2,4-triazolo-[5,1-c]-1,2,4-triazin-7-one sodium salt dihydrate (UPI-802). Objective: quantification of 2-ethylthio-6-nitro-1,2,4-triazolo-[5,1-c]-1,2,4-triazin-7-one sodium salt dihydrate by the method of voltammetry. For UPI-802, the signal of electroreduction of a nitro group is the most useful for quantitative determination. The processes of the nitro group reduction of the test substance in aqueous and aprotic solutions was studied using voltammetry in conditions of physical removal of dissolved oxygen and without oxygen removal. It was established that the rate of reduction of UPI-802 is controlled by diffusion, the processes of reduction of the nitro group is irreversible and proceeds in two stages in a Britton-Robinson buffer solution. The first recovery wave, lying in the potential region of -0,31 - (-0,8) V, corresponds to the addition of 4 electrons. It was found that the electroreduction of the nitro group proceeds with previous protonation. The optimal mode for recording the analytical signal of the UPI-802 on the glassy carbon electrode was selected in conditions of chemical method for removing dissolved oxygen – square-wave with a pulse amplitude of 0,05 V and a pulse frequency of 35 Hz. The possibility of using thick-film carbon-containing electrodes to determine the test substance by the method of square-wave voltammetry was shown. The quality indicators of the analysis technique, such as linearity, repeatability (convergence) and intralaboratory precision, were evaluated.
Zaidel, Peter. « Impacts of Small, Surface-Release Dams on Stream Temperature and Dissolved Oxygen in Massachusetts ». 2018. https://scholarworks.umass.edu/masters_theses_2/680.
Texte intégralWang, Xiaofei. « Impact of dissolved oxygen on PHA production and integration with biological nutrient removal processes ». Doctoral thesis, 2018. http://hdl.handle.net/10362/36290.
Texte intégralRocca, Jesse. « GA Optimized Fuzzy Logic Controller for the Dissolved Oxygen Concentration in a Wastewater Bioreactor ». Thesis, 2012. http://hdl.handle.net/10214/3690.
Texte intégralChou, Chih-Ming, et 周志明. « Influence of Dissolved Oxygen on Nitrogen and Phosphorus Removal from Municipal Wasterwater by Anaerobic-Aerobic-Anoxic-Aerobic Activated Sludge Process ». Thesis, 1996. http://ndltd.ncl.edu.tw/handle/09503466180876771827.
Texte intégral淡江大學
水資源及環境工程學系
84
This study is a experiment for taking nitrogen and phosphorus off from themunicipal wasterwater by "anaerobic- aerobic-anoxic-aerobic activated sludgeprocess". The experimental influent was typical municipal wasterwater with theflow of 60.0 L/hr,and 75% raw wastewater flow into the anaerobic tanks, theothers to the anoxic tanks, and the return sludge are 25%. The main controlfactor is dissolved oxygen concentration in the previous aerobic tanks, todiscuss the influences of different dissolved oxygen c oncentration aboutsimultanneous carbon,nitrogen and phosphorus removal. Because of rainingduring the period of experiment, it caused denitrification effect lower, andremoval efficiencies lower. This study is also discussing the influence aboutraining to the efficiencies and characteristics by nitrogen and phosphorusremoval from water with anaerobic-aerobic-anoxic- aerobic activated sludgeprocess. The conclusion about the influences of simultanneous carbon,nitrogenand phosphorus removal. in aerobic t anks DO=2.5,1.5,1.0 mg/L as follow. 1)Theaverage nitrification rate constant(KN) are 0.717, 0.619, and 0.313mgN/gMLSS/h. The KN in DO= 1.0 mg/L is about 50% in DO= 1.5 mg/L and Do= 2.5mg/L. It's beccuse the higher dissolved oxygen concentration can raise thenitrification rate and it is better for nitrified to multiply. It causedobvious differiences nitrification rate constant in the environment of higheror lower dissolved oxygen concentration. 2)When the average dissolved oxygenconcentration are 0. 5, 0.3, 0.2 and 0.0mg/L, the average denitrification rateconstant(KDN) are 0.258, 0.426, 0.477.and 0.631 mgN/gMLSS/h. The KDN of DO=0.5 in anoxic is about 40.9% in DO= 0.0mg/L. One of the elements to rasise theefficiencies of denitrification is to maintain the absolute anoxic conditionin anoxic tank. 3)During the constant raining period of time,the SBOD/P ofinfluent is between 6~9,and PO43- concentration of effluent is over 3.0 mg/Lin previous aerobic tank. And polyP organisms luxury uptake of p hosphorus isunobserved. It can't get effect of phosphorus removal. When the influentSBOD/P ≧ 12,the effluent PO43- concentration of previous aerobic tank isminor of 1.5 mg/L. And the polyP organisms luxury uptake of phosphorus isobviously. 4)During the unrained period of time, the influent SBOD/NOX-N ofanoxic tank is over 1.42, denitrification rate is over 85%. And during theconstant raining days, the nfluent SBOD/NOX-N of anoxic tank is lower to 1.0,denitrification rate is lower to 46.3~77.3%.It i s said that the higherSBOD/NOX-N will be good to the process of denitrification.
Carvalheira, Mónica Isabel Gonçalves. « The effect of key process operational conditions on enhanced biological phosphorus removal from wastewater ». Doctoral thesis, 2014. http://hdl.handle.net/10362/14295.
Texte intégral« Alkaline oxidation of hydrosulfide and methyl mercaptide by iron/cerium oxide-hydroxide in presence of dissolved oxygen. Possible application for removal of Total Reduced Sulfur (TRS) emissions in the Pulp & ; Paper industry ». Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24330/24330.pdf.
Texte intégral