Os sistemas de esgotos urbanos são classificados em separador absoluto, separador parcial e unitário, conforme o grau de separação que existe no recolhimento dos esgotos sanitários e das águas de drenagem pluviais. Embora a diretriz das cidades brasileiras seja a adoção do sistema separador, na prática ocorre uma importante contribuição das águas de chuvas nas vazões afluentes às estações de tratamento de esgotos como produto das interconexões existentes, clandestinas ou não, entre as redes de esgotos sanitários e pluviais. Esta pesquisa investigou os impactos causados pelos choques de carga orgânica e hidráulica provocados pela contribuição das águas pluviais no desempenho de reatores UASB e seu tempo de recuperação depois de sofrer estes choques. Três reatores de acrílico de 17 litros foram construídos no Laboratório de Saneamento Ambiental do IPH. Os reatores trataram esgoto sintético simulando a concentração de DQO de esgotos domésticos a uma temperatura de 30 ± 2 °C. Um dos reatores serviu de controle enquanto os outros dois receberam choques de carga hidráulica (aumento de vazão) e diluição de matéria orgânica, simultaneamente. A operação dos reatores foi dividida em três fases: 1°) aclimatação, 2°) choques individuais de carga hidráulica e diluição de matéria orgânica 3°) simulação de uma temporada de chuva. Os choques tiveram um efeito deletério na qualidade do efluente, ocasionando quedas na eficiência de remoção de DQO total de até quase 600% e de 200% na eficiência de remoção de DQO dissolvida nos choques mais severos. Também constatou-se perda de parte da biomassa presente nos reatores devido ao aumento excessivo na velocidade ascensional do fluxo. Esta perda tornou-se menor com o tempo devido à pressão de seleção exercida pelos sucessivos choques. O pH dentro dos reatores manteve-se sempre perto da faixa neutra, porém apresentou-se um consumo de alcalinidade que se prolongou por até três vezes o tempo de detenção hidráulica após o início dos choques, devido provavelmente ao aumento na concentração de ácidos graxos voláteis no efluente. A produção de biogás também diminuiu como conseqüência da diluição da carga orgânica afluente. Os efeitos e o tempo de recuperação após os choques dependeram da sua duração e magnitude, sendo que os choques mais severos (menor concentração de matéria orgânica afluente e TDH) causaram maior deterioração na qualidade do efluente e requereram maior tempo de recuperação.Já no que diz respeito às características físico-químicas e biológicas do lodo, verificou-se que os choques causaram diminuição no tamanho médio dos grânulos do lodo e na sua velocidade de sedimentação, provavelmente devido ao aumento das forças abrasivas v provocado pelo incremento na velocidade ascensional do fluxo. De igual modo, a atividade metanogênica específica também apresentou quedas devidas, provavelmente, à diluição da carga orgânica afluente e à diminuição do tamanho das partículas do lodo. / Sewerage systems are classified as separate, partially separated, or combined, according to the degree of separation that exists in the collection of municipal wastewater and stormwater runoff. Although the official policy of brazilian cities is for adoption of the separate system, the actual scenario shows that there are significant contributions of stormwater to the flows that are transported to the wastewater treatment plants, partly because of the inappropriate interconnections that exist between the systems. This research investigated the impacts that organic and hydraulic shock loads brought by stormwater contributions have on the efficiency of UASB reactors, as well as the recovery time after the ending of the shocks. Three 17-liters acrylic reactors were built in the Environmental Technology Laboratory at IPH. The reactors were fed with synthetic wastewater prepared to resemble the organic content of wastewater. All reactors were operated at a temperature of 30 ± 2ºC. One of the reactors was used as control while the other two received hydraulic shocks with organic matter dilution, simultaneously. Reactor’s operation was divided in three phases: 1º) star-up, 2º) single organic and hydraulic shocks, and 3º) rain season simulation, with multiple shocks.Shocks have a deleterious effect on the reactor effluent quality. In the most severe cases, drops in removal efficiencies reached up to 200% and 600% for dissolved and total DQO, respectively. Reactor biomass washout occurred due to the increasing upflow velocity. This loss was dampened by the selective pressure exerted by successive shocks. pH in the reactors remained in the neutral range, although alkalinity was consumed for as long as three detention times, probably due to an increase in the concentration of volatile fatty acids in the liquid. Dilution also caused a decrease in biogas production. Recovery time depended on the duration and intensity of the shock, with more severe shocks demanding more time for recovery. The impacts of the shocks on the treatment efficiency depended on duration, organic dilution rate and flowrate increase. Longer shocks, with higher flowrates and dilution rate resulted in the worst conditions for the reactor. Shocks loads caused a decrease in the mean size of the sludge granule, as well as in their sedimentation velocities, probably because of an increase in the abrasive forces acting on the granules brought by the upflow velocity. The specific methanogenic activity also decreased with higher dilution and smaller sized sludge granules.

Os sistemas de esgotos urbanos são classificados em separador absoluto, separador parcial e unitário, conforme o grau de separação que existe no recolhimento dos esgotos sanitários e das águas de drenagem pluviais. Embora a diretriz das cidades brasileiras seja a adoção do sistema separador, na prática ocorre uma importante contribuição das águas de chuvas nas vazões afluentes às estações de tratamento de esgotos como produto das interconexões existentes, clandestinas ou não, entre as redes de esgotos sanitários e pluviais. Esta pesquisa investigou os impactos causados pelos choques de carga orgânica e hidráulica provocados pela contribuição das águas pluviais no desempenho de reatores UASB e seu tempo de recuperação depois de sofrer estes choques. Três reatores de acrílico de 17 litros foram construídos no Laboratório de Saneamento Ambiental do IPH. Os reatores trataram esgoto sintético simulando a concentração de DQO de esgotos domésticos a uma temperatura de 30 ± 2 °C. Um dos reatores serviu de controle enquanto os outros dois receberam choques de carga hidráulica (aumento de vazão) e diluição de matéria orgânica, simultaneamente. A operação dos reatores foi dividida em três fases: 1°) aclimatação, 2°) choques individuais de carga hidráulica e diluição de matéria orgânica 3°) simulação de uma temporada de chuva. Os choques tiveram um efeito deletério na qualidade do efluente, ocasionando quedas na eficiência de remoção de DQO total de até quase 600% e de 200% na eficiência de remoção de DQO dissolvida nos choques mais severos. Também constatou-se perda de parte da biomassa presente nos reatores devido ao aumento excessivo na velocidade ascensional do fluxo. Esta perda tornou-se menor com o tempo devido à pressão de seleção exercida pelos sucessivos choques. O pH dentro dos reatores manteve-se sempre perto da faixa neutra, porém apresentou-se um consumo de alcalinidade que se prolongou por até três vezes o tempo de detenção hidráulica após o início dos choques, devido provavelmente ao aumento na concentração de ácidos graxos voláteis no efluente. A produção de biogás também diminuiu como conseqüência da diluição da carga orgânica afluente. Os efeitos e o tempo de recuperação após os choques dependeram da sua duração e magnitude, sendo que os choques mais severos (menor concentração de matéria orgânica afluente e TDH) causaram maior deterioração na qualidade do efluente e requereram maior tempo de recuperação.Já no que diz respeito às características físico-químicas e biológicas do lodo, verificou-se que os choques causaram diminuição no tamanho médio dos grânulos do lodo e na sua velocidade de sedimentação, provavelmente devido ao aumento das forças abrasivas v provocado pelo incremento na velocidade ascensional do fluxo. De igual modo, a atividade metanogênica específica também apresentou quedas devidas, provavelmente, à diluição da carga orgânica afluente e à diminuição do tamanho das partículas do lodo. / Sewerage systems are classified as separate, partially separated, or combined, according to the degree of separation that exists in the collection of municipal wastewater and stormwater runoff. Although the official policy of brazilian cities is for adoption of the separate system, the actual scenario shows that there are significant contributions of stormwater to the flows that are transported to the wastewater treatment plants, partly because of the inappropriate interconnections that exist between the systems. This research investigated the impacts that organic and hydraulic shock loads brought by stormwater contributions have on the efficiency of UASB reactors, as well as the recovery time after the ending of the shocks. Three 17-liters acrylic reactors were built in the Environmental Technology Laboratory at IPH. The reactors were fed with synthetic wastewater prepared to resemble the organic content of wastewater. All reactors were operated at a temperature of 30 ± 2ºC. One of the reactors was used as control while the other two received hydraulic shocks with organic matter dilution, simultaneously. Reactor’s operation was divided in three phases: 1º) star-up, 2º) single organic and hydraulic shocks, and 3º) rain season simulation, with multiple shocks.Shocks have a deleterious effect on the reactor effluent quality. In the most severe cases, drops in removal efficiencies reached up to 200% and 600% for dissolved and total DQO, respectively. Reactor biomass washout occurred due to the increasing upflow velocity. This loss was dampened by the selective pressure exerted by successive shocks. pH in the reactors remained in the neutral range, although alkalinity was consumed for as long as three detention times, probably due to an increase in the concentration of volatile fatty acids in the liquid. Dilution also caused a decrease in biogas production. Recovery time depended on the duration and intensity of the shock, with more severe shocks demanding more time for recovery. The impacts of the shocks on the treatment efficiency depended on duration, organic dilution rate and flowrate increase. Longer shocks, with higher flowrates and dilution rate resulted in the worst conditions for the reactor. Shocks loads caused a decrease in the mean size of the sludge granule, as well as in their sedimentation velocities, probably because of an increase in the abrasive forces acting on the granules brought by the upflow velocity. The specific methanogenic activity also decreased with higher dilution and smaller sized sludge granules.

Os sistemas de esgotos urbanos são classificados em separador absoluto, separador parcial e unitário, conforme o grau de separação que existe no recolhimento dos esgotos sanitários e das águas de drenagem pluviais. Embora a diretriz das cidades brasileiras seja a adoção do sistema separador, na prática ocorre uma importante contribuição das águas de chuvas nas vazões afluentes às estações de tratamento de esgotos como produto das interconexões existentes, clandestinas ou não, entre as redes de esgotos sanitários e pluviais. Esta pesquisa investigou os impactos causados pelos choques de carga orgânica e hidráulica provocados pela contribuição das águas pluviais no desempenho de reatores UASB e seu tempo de recuperação depois de sofrer estes choques. Três reatores de acrílico de 17 litros foram construídos no Laboratório de Saneamento Ambiental do IPH. Os reatores trataram esgoto sintético simulando a concentração de DQO de esgotos domésticos a uma temperatura de 30 ± 2 °C. Um dos reatores serviu de controle enquanto os outros dois receberam choques de carga hidráulica (aumento de vazão) e diluição de matéria orgânica, simultaneamente. A operação dos reatores foi dividida em três fases: 1°) aclimatação, 2°) choques individuais de carga hidráulica e diluição de matéria orgânica 3°) simulação de uma temporada de chuva. Os choques tiveram um efeito deletério na qualidade do efluente, ocasionando quedas na eficiência de remoção de DQO total de até quase 600% e de 200% na eficiência de remoção de DQO dissolvida nos choques mais severos. Também constatou-se perda de parte da biomassa presente nos reatores devido ao aumento excessivo na velocidade ascensional do fluxo. Esta perda tornou-se menor com o tempo devido à pressão de seleção exercida pelos sucessivos choques. O pH dentro dos reatores manteve-se sempre perto da faixa neutra, porém apresentou-se um consumo de alcalinidade que se prolongou por até três vezes o tempo de detenção hidráulica após o início dos choques, devido provavelmente ao aumento na concentração de ácidos graxos voláteis no efluente. A produção de biogás também diminuiu como conseqüência da diluição da carga orgânica afluente. Os efeitos e o tempo de recuperação após os choques dependeram da sua duração e magnitude, sendo que os choques mais severos (menor concentração de matéria orgânica afluente e TDH) causaram maior deterioração na qualidade do efluente e requereram maior tempo de recuperação.Já no que diz respeito às características físico-químicas e biológicas do lodo, verificou-se que os choques causaram diminuição no tamanho médio dos grânulos do lodo e na sua velocidade de sedimentação, provavelmente devido ao aumento das forças abrasivas v provocado pelo incremento na velocidade ascensional do fluxo. De igual modo, a atividade metanogênica específica também apresentou quedas devidas, provavelmente, à diluição da carga orgânica afluente e à diminuição do tamanho das partículas do lodo. / Sewerage systems are classified as separate, partially separated, or combined, according to the degree of separation that exists in the collection of municipal wastewater and stormwater runoff. Although the official policy of brazilian cities is for adoption of the separate system, the actual scenario shows that there are significant contributions of stormwater to the flows that are transported to the wastewater treatment plants, partly because of the inappropriate interconnections that exist between the systems. This research investigated the impacts that organic and hydraulic shock loads brought by stormwater contributions have on the efficiency of UASB reactors, as well as the recovery time after the ending of the shocks. Three 17-liters acrylic reactors were built in the Environmental Technology Laboratory at IPH. The reactors were fed with synthetic wastewater prepared to resemble the organic content of wastewater. All reactors were operated at a temperature of 30 ± 2ºC. One of the reactors was used as control while the other two received hydraulic shocks with organic matter dilution, simultaneously. Reactor’s operation was divided in three phases: 1º) star-up, 2º) single organic and hydraulic shocks, and 3º) rain season simulation, with multiple shocks.Shocks have a deleterious effect on the reactor effluent quality. In the most severe cases, drops in removal efficiencies reached up to 200% and 600% for dissolved and total DQO, respectively. Reactor biomass washout occurred due to the increasing upflow velocity. This loss was dampened by the selective pressure exerted by successive shocks. pH in the reactors remained in the neutral range, although alkalinity was consumed for as long as three detention times, probably due to an increase in the concentration of volatile fatty acids in the liquid. Dilution also caused a decrease in biogas production. Recovery time depended on the duration and intensity of the shock, with more severe shocks demanding more time for recovery. The impacts of the shocks on the treatment efficiency depended on duration, organic dilution rate and flowrate increase. Longer shocks, with higher flowrates and dilution rate resulted in the worst conditions for the reactor. Shocks loads caused a decrease in the mean size of the sludge granule, as well as in their sedimentation velocities, probably because of an increase in the abrasive forces acting on the granules brought by the upflow velocity. The specific methanogenic activity also decreased with higher dilution and smaller sized sludge granules.

No description available.

Die vorliegende Arbeit beschäftigt sich mit der Thematik des hydraulischen Feststofftransports in Druckrohrleitungen zur Bestimmung der hydraulischen Energieverluste des Wasser-Feststoff-Gemisches und der wirtschaftlichen Gemischgeschwindigkeit (der s.g. kritischen Geschwindigkeit) vcrit. Zu diesem Zweck wurde der Transportvorgang in verschiedenen Rohrkonfigurationen (horizontal, schräg und z. T. vertikal) an einem physikalischen Modell im Hubert-Engels-Labor des Instituts für Wasserbau und Technische Hydromechanik der Technischen Universität Dresden untersucht. Dabei kamen drei Sandfraktionen zum Einsatz (0,1 - 0,5 mm; 0,71 - 1,25 mm und 1,4 - 2,2 mm). Die Partikel weisen eine Dichte von ρF=2650 kg/m³ auf. Ziel der Untersuchungen war, mithilfe der Messdaten eine Formel zur Berechnung des Verlustanteils der dispersen Phase an dem gesamten Energieverlust besonders für das heterogene und das quasi-homogene Transportregime in Abhängigkeit von den Einflussgrößen (Dichte, Konzentration, Partikeldurchmesser etc.) abzuleiten. Ein weiterer Schwerpunkt der Arbeit war, die kritische Gemischgeschwindigkeit genauer zu betrachten und einen entsprechenden Rechenansatz aufzustellen. Diese Geschwindigkeit stellt den Übergang von dem Transport mit beweglicher Sohle zum heterogenen Feststofftransport dar. Nach Abschluss der physikalischen Versuche wurde der Feststofftransport mit der Software ANSYS-Fluent numerisch untersucht. Im Fokus der Modellierung stand die Festsetzung der Wandrandbedingung für die disperse Phase, mit Hilfen derer die physikalisch gemessenen Energieverluste erreicht werden konnten. Die Simulationen wurden mit dem Euler-Granular-Modell durchgeführt. Hierbei wird der Feststoff als zweites Kontinuum betrachtet und seine rheologischen Eigenschaften wurden durch die Erweiterung der kinetischen Theorie der Gase auf die disperse Phase (eng. kinetic theory of granular flow KTGF) berechnet. Das angewendete zwei-Fluid-Modell (TFM) eignet sich sehr gut für alle möglichen vorkommenden Feststoffkonzentrationen und liefert gute Übereinstimmung mit den Messergebnissen im Gegensatz zu dem Euler-Lagrange-Modell (DPM), welches lediglich bei niedrigen Feststoffkonzentrationen Anwendung findet.:Inhaltsverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Symbolverzeichnis Indexverzeichnis 1 Einleitung und Zielsetzung 2 Grundlagen des hydraulischen Feststofftransports in Rohrleitungen 2.1 Das Energiegesetz 2.2 Feststofftransport in Rohrleitungen 2.3 Partikeleigenschaften 2.4 Typisierung der Partikelbewegung mit der Strömung 2.5 Einfluss der Turbulenz auf die Partikelbewegung in horizontaler Rohrleitung 2.6 Transportzustände in horizontaler Rohrleitung 2.7 Transportzustände in vertikaler Rohrleitung 2.8 Stopfgrenze 2.9 Kräftebilanz an einem Feststoffpartikel 2.10 Dimensionsanalyse 2.10.1 Auflistung der Einflussgrößen 2.10.2 Anzahl der dimensionslosen π-Parameter 2.10.3 Auswahl der Hauptvariablen 2.10.4 Ermittlung der π-Parameter 2.10.5 Form des funktionellen Zusammenhangs 3 Bemessungsansätze des hydraulischen Transports 3.1 Stand des Wissens 3.1.1 Feststofftransport in horizontaler Rohrleitung 3.1.2 Feststofftransport in geneigter Rohrleitung 3.1.3 Feststofftransport in vertikaler Rohrleitung 3.1.4 Die kritische Gemischgeschwindigkeit in horizontaler Rohrleitung 3.1.5 Die kritische Gemischgeschwindigkeit in geneigter Rohrleitung 3.1.6 Weitere Rechenmodelle 3.2 Erweiterung des Energiegesetzes auf Gemischströmung 3.2.1 In horizontaler Rohrleitung 3.2.2 In geneigter Rohrleitung 3.2.3 In vertikaler Rohrleitung 4 Experimentelle Untersuchungen 4.1 Aufbau der ersten Versuchsanlage 4.2 Messtechnik 4.3 Umbau der Versuchsanlage 4.4 Untersuchungsmaterial 4.5 Experimentelles Verfahren 5 Numerische Simulationen mit ANSYS-Fluent 5.1 Grundlagen der Mehrphasenströmungen 5.2 Auswahl des numerischen Modells 5.3 Das Granular-Euler-Modell 5.3.1 Die Erhaltungsgleichung 5.3.2 Die kinetische Theorie der dispersen Phase 5.4 Modellvalidierung 6 Vorstellung der Untersuchungsergebnisse 6.1 Ergebnisse der experimentellen Untersuchungen in horizontaler Leitung 6.1.1 Experimentelle Untersuchungen zum Energieverlust 6.1.2 Experimentelle Untersuchung zu der kritischen Geschwindigkeit 6.2 Ergebnisse der hydronumerischen Untersuchungen in horizontaler Rohrleitung 6.2.1 Randbedingungen 6.2.2 Numerische Lösung und Konvergenz 6.2.3 Parameteranalyse anhand eigener Versuche 6.2.4 Numerische Untersuchungen zur Wechselwirkung zwischen den hydraulischen Kenngrößen 6.3 Ergebnisse der experimentellen Untersuchungen in vertikaler Leitung 6.4 Ergebnisse der experimentellen Untersuchungen in geneigter Rohrleitung 6.4.1 Experimentelle Untersuchungen zum Energieverlust 6.4.2 Experimentelle Untersuchung zu der kritischen Gemischgeschwindigkeit 6.5 Ergebnisse der numerischen Untersuchungen in geneigter Rohrleitung 7 Fehleranalyse und weitere Betrachtungen 7.1 Degradierung des Feststoffes 7.2 Die Abnutzung der Pumpe 7.3 Abrieb und Durchbruch der Rohrleitungen 7.4 Die Instabilität des Systems bei geringen Geschwindigkeiten 7.5 Messabweichung des Durchflussmessers 7.6 Fehlerquelle bei der Untersuchung der kritischen Gemischgeschwindigkeit 7.7 Fortbewegung der Feststoffe bei Geschwindigkeiten unterhalb vcrit 7.8 Einfluss der Transportkonzentration auf den Arbeitspunkt der Pumpe 8 Zusammenfassung Literaturverzeichnis Anhang / The present work deals with the hydraulic transport characteristics of sand-water mixtures in pipelines to determine hydraulic gradients and the deposition-limit velocity (critical velocity). For this purpose, the transport process in various pipe configurations (horizontal, inclined and vertical) was investigated on a physical model at the Hubert Engels Laboratory of the Institute of Hydraulic Engineering and Technical Hydromechanics of the Technical University of Dresden. Three sand fractions were used (0.1 - 0.5 mm, 0.71 - 1.25 mm and 1.4 - 2.2 mm) with particles density of ρF = 2650 kg/m³. The aim of the investigations was to develop a model for calculating the head loss percent-age of the disperse phase in terms of total energy loss, especially for the heterogeneous and quasi-homogeneous transport regime correlating to the influence quantities (density, concentration, particle diameter, etc.). Another important aspect for this work was to consider the critical velocity and to set up a corresponding calculation approach for this parameter. The deposition-limit velocity represents the transition from sliding Bed transport to heterogeneous transport. In the next step, the solids transport process was investigated numerical with ANSYS-Fluent. The focus of the modeling was the determination of the wall boundary condition for the disperse phase, with help of which the physically measured energy losses could be re-stored. The simulations were performed with the Euler Granular model. Here, the solid is considered to be the second continuum, and its rheological properties were calculated by expanding the kinetic theory of gases to disperse phase (KTGF).:Inhaltsverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Symbolverzeichnis Indexverzeichnis 1 Einleitung und Zielsetzung 2 Grundlagen des hydraulischen Feststofftransports in Rohrleitungen 2.1 Das Energiegesetz 2.2 Feststofftransport in Rohrleitungen 2.3 Partikeleigenschaften 2.4 Typisierung der Partikelbewegung mit der Strömung 2.5 Einfluss der Turbulenz auf die Partikelbewegung in horizontaler Rohrleitung 2.6 Transportzustände in horizontaler Rohrleitung 2.7 Transportzustände in vertikaler Rohrleitung 2.8 Stopfgrenze 2.9 Kräftebilanz an einem Feststoffpartikel 2.10 Dimensionsanalyse 2.10.1 Auflistung der Einflussgrößen 2.10.2 Anzahl der dimensionslosen π-Parameter 2.10.3 Auswahl der Hauptvariablen 2.10.4 Ermittlung der π-Parameter 2.10.5 Form des funktionellen Zusammenhangs 3 Bemessungsansätze des hydraulischen Transports 3.1 Stand des Wissens 3.1.1 Feststofftransport in horizontaler Rohrleitung 3.1.2 Feststofftransport in geneigter Rohrleitung 3.1.3 Feststofftransport in vertikaler Rohrleitung 3.1.4 Die kritische Gemischgeschwindigkeit in horizontaler Rohrleitung 3.1.5 Die kritische Gemischgeschwindigkeit in geneigter Rohrleitung 3.1.6 Weitere Rechenmodelle 3.2 Erweiterung des Energiegesetzes auf Gemischströmung 3.2.1 In horizontaler Rohrleitung 3.2.2 In geneigter Rohrleitung 3.2.3 In vertikaler Rohrleitung 4 Experimentelle Untersuchungen 4.1 Aufbau der ersten Versuchsanlage 4.2 Messtechnik 4.3 Umbau der Versuchsanlage 4.4 Untersuchungsmaterial 4.5 Experimentelles Verfahren 5 Numerische Simulationen mit ANSYS-Fluent 5.1 Grundlagen der Mehrphasenströmungen 5.2 Auswahl des numerischen Modells 5.3 Das Granular-Euler-Modell 5.3.1 Die Erhaltungsgleichung 5.3.2 Die kinetische Theorie der dispersen Phase 5.4 Modellvalidierung 6 Vorstellung der Untersuchungsergebnisse 6.1 Ergebnisse der experimentellen Untersuchungen in horizontaler Leitung 6.1.1 Experimentelle Untersuchungen zum Energieverlust 6.1.2 Experimentelle Untersuchung zu der kritischen Geschwindigkeit 6.2 Ergebnisse der hydronumerischen Untersuchungen in horizontaler Rohrleitung 6.2.1 Randbedingungen 6.2.2 Numerische Lösung und Konvergenz 6.2.3 Parameteranalyse anhand eigener Versuche 6.2.4 Numerische Untersuchungen zur Wechselwirkung zwischen den hydraulischen Kenngrößen 6.3 Ergebnisse der experimentellen Untersuchungen in vertikaler Leitung 6.4 Ergebnisse der experimentellen Untersuchungen in geneigter Rohrleitung 6.4.1 Experimentelle Untersuchungen zum Energieverlust 6.4.2 Experimentelle Untersuchung zu der kritischen Gemischgeschwindigkeit 6.5 Ergebnisse der numerischen Untersuchungen in geneigter Rohrleitung 7 Fehleranalyse und weitere Betrachtungen 7.1 Degradierung des Feststoffes 7.2 Die Abnutzung der Pumpe 7.3 Abrieb und Durchbruch der Rohrleitungen 7.4 Die Instabilität des Systems bei geringen Geschwindigkeiten 7.5 Messabweichung des Durchflussmessers 7.6 Fehlerquelle bei der Untersuchung der kritischen Gemischgeschwindigkeit 7.7 Fortbewegung der Feststoffe bei Geschwindigkeiten unterhalb vcrit 7.8 Einfluss der Transportkonzentration auf den Arbeitspunkt der Pumpe 8 Zusammenfassung Literaturverzeichnis Anhang

L’objectif de cette thèse est de proposer un modèle d’érosion diffuse qui intègre les principaux processus de ce phénomène (détachement, transport, sédimentation) et qui prend en compte l’interaction des gouttes de pluie avec ces processus. Dans un premier temps, nous avons établi une loi de détachement par la pluie qui inclut l’effet des gouttes et celui de l’épaisseur de la lame d’eau qui couvre la surface du sol. Pour obtenir cette loi, une étude numérique avec le logiciel Gerris a permis de modéliser les cisaillements créés par l’impact des gouttes sur des épaisseurs de lame d’eau variables. Ces cisaillements estiment la quantité de sol détaché par chaque goutte. Nous avons montré, à travers une étude probabiliste, que les gouttes sont quasiment indépendantes lors du détachement. Les détachements de l’ensemble des gouttes sont donc sommés pour établir la loi de détachement pour la pluie. Par ailleurs, l’étude probabiliste a montré la possibilité d’une forte interaction entre les gouttes de pluie et les particules en sédimentation. Par conséquent, pour le processus de transport-sédimentation, nous avons privilégié une approche expérimentale. Cette étude a révélé que l’effet des gouttes de pluie est d’augmenter la vitesse de sédimentation des particules. Enfin, nous avons proposé un nouveau modèle d’érosion qui généralise plusieurs modèles d’érosion de la littérature et décrit l’évolution des concentrations en sédiments avec des effets linéaires et non-linéaires. Selon le choix des paramètres du modèle, celui-ci peut représenter l’érosion diffuse et concentrée à l’échelle du bassin versant, le transport par charriage dans les rivières ou encore le transport chimique. L’intégration du modèle dans le logiciel de ruissellement FullSWOF est aussi réalisée. / The aim of this work is to formulate an interrill erosion model. This model should take into account the main erosion processes (detachment, transport and sedimentation) and the interaction of raindrops during these processes. First we develop a law for rainfall detachment that includes the effects of the raindrops and the water layer thickness at the soil surface. We use the Gerris software to simulate the shear stresses created by the impacts of raindrops at the soil surface. These shear stresses allow to evaluate the quantity of soil detached by each raindrop. We have shown with a probabilistic approach that raindrops are almost independent during soil detachment. Then by summing all the raindrops detachments we obtain the rainfall detachment law. Futhermore the probabilistic study has revealed the possibility of a strong interaction between raindrops and settling particles. So, we used specific laboratory experiments to investigate the particles transport and sedimentation processes. These experiments show that the effect of raindrops is to increase the particles settling velocity. Finally, we propose a new erosion model which encompasses previous literature erosion models and that can describe the behavior of sediments concentrations with linear and non-linear behaviors. The model is able to simulate interrill and rill erosions at the watershed scale, bedload transport in rivers and chemical transfer. The integration of the model in the FullSWOF runoff software is also carried out.

<p>This thesis presents predictive models for important variables concerning eutrophication effects in lakes. The keystone is a dynamic phosphorus model based on ordinary differential equations. By calculating mass fluxes of phosphorus into, within and out from a lake, the concentrations of different forms of phosphorus in different compartments of the lake are estimated.</p><p>The dynamic phosphorus model is critically tested and several improvements are presented, including two new compartments for colloidal phosphorus, a sub-model for suspended particulate matter (SPM) and new algorithms for lake outflow, water mixing, diffusion, water content and organic content of accumulation sediments are implemented. Predictions with the new version show good agreement against empirical data in five tested lakes.</p><p>The sub-model for SPM uses the same driving variables as the basic phosphorus model, so the inclusion of this model as a sub-model does not require any additional variables. The model for SPM may also be used as a separate model giving monthly predictions of suspended particulate matter in two water compartments and one compartment with SPM available for resuspension in ET-sediments.</p><p>Empirical data from Lake Erken (Sweden) and Lake Balaton (Hungary) are used to evaluate the variability in settling velocity of SPM. It is found that the variability is substantial and may be accounted for by using a dimensionless moderator for SPM concentration. Empirical data from accumulation area sediments in Lake Erken are used to develop a model for the dynamics of phosphorus sedimentation, burial and diffusion in the sediments. The model is shown to provide reasonable monthly predictions of four functional forms of phosphorus at different sediment depths.</p><p>Simulations with the lake phosphorus model using two different climate scenarios indicate that lakes may respond very differently to climate change depending on their physical character. Lake Erken, with a water retention time of 7 years, appears to be much more sensitive than two basins of Lake Mälaren (Sweden) with substantially shorter retention times. The implication would be that in eutrophic lakes with long water retention times, eutrophication problems may become serious if the future becomes warmer. This will be important in contexts of lake management when remedial measures against lake eutrophication have to be taken.</p>

This thesis presents predictive models for important variables concerning eutrophication effects in lakes. The keystone is a dynamic phosphorus model based on ordinary differential equations. By calculating mass fluxes of phosphorus into, within and out from a lake, the concentrations of different forms of phosphorus in different compartments of the lake are estimated. The dynamic phosphorus model is critically tested and several improvements are presented, including two new compartments for colloidal phosphorus, a sub-model for suspended particulate matter (SPM) and new algorithms for lake outflow, water mixing, diffusion, water content and organic content of accumulation sediments are implemented. Predictions with the new version show good agreement against empirical data in five tested lakes. The sub-model for SPM uses the same driving variables as the basic phosphorus model, so the inclusion of this model as a sub-model does not require any additional variables. The model for SPM may also be used as a separate model giving monthly predictions of suspended particulate matter in two water compartments and one compartment with SPM available for resuspension in ET-sediments. Empirical data from Lake Erken (Sweden) and Lake Balaton (Hungary) are used to evaluate the variability in settling velocity of SPM. It is found that the variability is substantial and may be accounted for by using a dimensionless moderator for SPM concentration. Empirical data from accumulation area sediments in Lake Erken are used to develop a model for the dynamics of phosphorus sedimentation, burial and diffusion in the sediments. The model is shown to provide reasonable monthly predictions of four functional forms of phosphorus at different sediment depths. Simulations with the lake phosphorus model using two different climate scenarios indicate that lakes may respond very differently to climate change depending on their physical character. Lake Erken, with a water retention time of 7 years, appears to be much more sensitive than two basins of Lake Mälaren (Sweden) with substantially shorter retention times. The implication would be that in eutrophic lakes with long water retention times, eutrophication problems may become serious if the future becomes warmer. This will be important in contexts of lake management when remedial measures against lake eutrophication have to be taken.

Les contaminants, dissouts ou adsorbés sur les particules, sont principalement délivrés au milieu marin par les fleuves. La dynamique sédimentaire constitue alors un proxy de la dynamique de ces contaminants. Cette thèse s'inscrit dans le projet ANR AMORAD, et se focalise sur la dynamique du matériel particulaire délivré par le Rhône au Golfe du Lion (Méditerranée nord-occidentale), principal contributeur d'apports solides au Golfe (80 % des sédiments). Alors que des études antérieures ont permis de bien représenter les processus au niveau du fond, les processus régissant les comportements des matières en supension (MES), majoritairement rencontrées dans le panache turbide du Rhône, sont encore mal apréhendés. En vue de mieux décrire la dynamique de ces MES et d'améliorer les modèles hydrosédimentaires existants, l'objectif est de mieux caractériser ces particules. À cette fin, un vaste jeu de données issu de capteurs déployés in situ (données collectées pour 12 campagnes en mer, réalisées de 2011 à 2016) a été exploité, permettant d’obtenir une vision 2D verticale mais seulement ponctuelle (spatialement et temporellement). De façon complémentaire, une base de données d'images satellitaires (donnée couleur de l'eau du capteur MERIS-300m acquise entre 2002 et 2012), offrant une vue plus synoptique et long terme mais uniquement en surface, a été exploitée. Le jeu de données d'images satellitaire (plus de 800 images) a été traité de façon innovante par l'application d'un traitement semi-automatique permettant l'extraction de différentes métriques du panache turbide du Rhône (e.g. aire, limites d'extension, forme, centres géométriques, concentrations). La distribution spatiale et les caractéristiques physiques des MES telles que leur concentration dans l'eau, leur diamètre médian ou encore leur vitesse de chute ont été étudiées et estimées en fonction des différents forçages hydrométéorologiques actifs sur la zone d'étude (e.g. débit du Rhône, vents dominants). Un nouveau modèle hydrosédimentaire reposant sur le couplage du modèle hydrodynamique MARS-3D et du module sédimentaire multiclasse MIXSED a été configuré et les données in situ et satellitaires ont pu être mobilisées afin de contraindre la vitesse de chute des sédiments, paramètre clef de la modélisation de la dynamique hydrosédimentaire. / Contaminants, which can be dissolved in water or adsorbed on particles, are mainly delivered to the coastal environment by rivers. Thus, sediment dynamics reperesent a relevant proxy of contaminants dynamics. ThisPhD thesis is part of the ANR AMORAD project, of which one workpackage focuses on the fate of sediments in the coastal environment. This work focuses on the dynamics of Rhône River sediments in the Gulf of Lions (north-western mediterranean), this river delivering 80 % of the sediments of the Gulf. While previous studies over the area allowed a better understanding of physical processes at the water-sediment interface, processes driving suspended particulate matter (SPM) dynamics are still poorly understood. To better describe this SPM dynamics and improve hydrosedimentary models, the aim is to better characterize these particles. To this end, a large dataset collected from in situ deployed sensors (data collected for 12 field campaigns, conducted from 2011 to 2016) was analyzed to get a 2D vertical but ponctual view (both spatially and temporally). Complementary, a satellite images dataset (MERIS-300m ocean colour archive from 2002 to 2012) was built in order to get a long term and more synoptic view (but limited to surface).This dataset (more than 800 images) was originaly studied, applying a semi-empirical process to extract various Rhône River turbid plume metrics (e.g. area of extension, south-east-westernmost points, shape, centroids, SPM concentrations). Plume metrics and physical properties of SPM such as their concentration in water, their median diameter or their settling velocity were investigated regarding the different hydrometeorological forcings (e.g. Rhône River discharge, prevailing winds). A new hydrosedimentary model, based on the coupling of the 3D hydrodynamical model MARS-3D and the sedimentary module MIXSED, was set and ocean color and in situ data were used to constrain the settling velocity of particles, key parameter of hydrosedimentary modelling.

No / Sedimentation of non-homogeneous systems is the typical phenomenon indicating the physical instability as a key measure to the quality control of the preparation products. Currently, the determination methods for the sedimentation of non-homogeneous preparations are based on manual measurement or semi-quantitative observation, lacking of either automation or quantitative dynamic analysis. The purpose of this research was to realize automatic and quantitative monitoring of the sedimentation dynamics for non-homogenous systems as suspension, emulsions at laboratory level. Non-contact measurement method has been established to determine the sedimentation behaviors in a standard quartz tube for sedimentation, with internal diameter and height 23 mm and 215 mm, respectively, with controlled temperature and light intensity. As high performance camera has been equipped, the sedimentation images with high spatial and temporal resolution could be acquired, which can continuously capture sedimentation images with the resolution of 2048 x 2048 pixel at a maximum rate of 60 slides/s. All the pictures were processed to extract the luminance matrix top-down along the fixed vertical midline of each picture, which implied sedimentation characteristics of the system at the moment the picture was taken. Combining all the luminance matrixes along vertical middle lines of the pictures, a time-luminance matrix profile was obtained. Digital image processing techniques were used to eliminate interference and establish a three-dimensional surface model of the sedimentation dynamics. Then, the derivative mutation algorithm has been developed for the intelligent identification of sedimentation interface with threshold optimization so as to quantitatively analyze the sedimentation dynamics with visualization. The sedimentation curve and sedimentation dynamic equation of the non-homogeneous system were finally outputted by numerical fitting. The methodology was validated for great significance in determinations of small volume samples, parallel control multiple batches, and long period of time automatic measurement. (C) 2015 Elsevier B.V. All rights reserved.