Made available in DSpace on 2014-06-11T19:23:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-04-12Bitstream added on 2014-06-13T18:50:41Z : No. of bitstreams: 1 santos_jm_me_bauru.pdf: 549067 bytes, checksum: 7489ebe71b862060486033eb00f03299 (MD5) / Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico do Maranhão (FAPEMA) / Esse estudo investigou a cinética de coagulação floculação do TiO2 em suspensão aquosa de baixa força iônica (água destilada)e força iônica média (água de abastecime to público),em função do pH e da adição de sulfato de alumínio. A coagulação floculação do TiO2 ocorre quando o pH é ajustado próximo ao pH do potencial isoelétrico, pela compressão da camada de difusão ou pela adsorção hidrólise com íons Al 3+ . Em suspensões de TiO2 com baixa força iônica,a coagulação ocorre a um determinado pH (4,0 e 7,0), uma vez que ele depende basicamente da superfície do óxido. Com adição de um coadjuvante de sedimentação (por ex. sulfato de alumínio), a qual a força iônica é alta,a coagulação floculação ocorre muito rápido. O tempo de decantação do material em suspensão foi de 2:00 h, foi comparada a cinética de sedimentação da decantação simples com a realizada em Jar Test sob a influência de agitação rápida (eletrocinético) e lenta (ortocinético) antes de permitir a sedimentação. O melhor desempenho foi em Jar Test,turbidez final de 10 NTU. / This study investigated the coagulation-flocculation kinetics of TiO2 in an aqueous Suspension of low-strength ionic solution (distilled water) and a medium strength ionic solution (tap water) as a function of pH and of the addition of aluminum sulfate. Coagulation-flocculation of TiO2 occurs when the pH is adjusted close to the isoelectric potential (iep), by compression of the diffusion layer or by adsorption-hydrolysis with Al 3+ ions. In TiO2 suspensions with low electric strength,coagulation takes place at certain pH (4,0 a d 7,0) since it depends basically on the oxide surface.With the addition of sedimentation aid (e.g.,aluminum sulfate), in which the ionic strength is high, coagulation-flocculation, takes place very fast. The decantation time of the material in suspension was of 2h. The sedimentation kinetic of the simple decantation was compared to that carried out in Jar Test under influence of fast stirring (electrokinetic) and slow stirring (ortokinetic) before sedimentation set up.The best performance was in Jar Test,final turbidez of 10 NTU.

Made available in DSpace on 2014-06-11T19:29:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-04-08Bitstream added on 2014-06-13T19:59:02Z : No. of bitstreams: 1 cestari_jl_me_ilha.pdf: 749272 bytes, checksum: 806535e7789d2b8561b9f26df18476ef (MD5) / Utilizando-se um floculador mecanizado com quatro câmaras foram realizados ensaios hidrodinâmicos com o traçador cloreto de sódio obtendo-se curvas de distribuição dos tempos de residência (DTR) e os tempos de residência médios para os tempos de residência teórico de 29,54 min, 22,15 min e 14,77 min respectivamente para o floculador operando com 04, 03 e 02 câmaras. Entre as câmaras de floculação havia quatro diferentes posições de passagens, sendo duas em cima “D” e “E” (respectivamente Direita superior e Esquerda superior) e duas embaixo “d” e “e” (respectivamente direita inferior e esquerda inferior). Levando-se em consideração que a entrada de água era realizada na passagem “e”, foram combinadas quatro configurações de passagem para floculador de 04 câmaras (eEeEe , eDeDe , edede e eeeee) e uma quinta empregando-se anteparos (e/e/e/e/e). As mesmas configurações foram estendidas ao floculador operando com 03 e 02 câmaras. Procurou-se avaliar nos floculadores, operando sob as diferentes configurações de passagem apresentadas acima, a magnitude dos efeitos dos curtos-circuitos de acordo com os estudos pré- definidos. Tais estudos combinaram o sentido de rotação dos agitadores (sentido alternado e mesmo sentido de rotação ao longo das câmaras) com a constância ou a variação do gradiente de floculação, além de um estudo com os agitadores desligados. Observou-se, após a análise das curvas DTR, que as configurações edede e e/e/e/e/e para floculador de 04 câmaras, estendidas aos floculadores de 03 e 02 câmaras, apresentaram menor incidência de curtos-circuitos que a configuração eEeEe. A colocação do anteparo que gerou a configuração e/e/e/e/e para floculador de 04 câmaras, estendida aos floculadores de 03 e 02 câmaras, mostrou-se uma alternativa... / Using a mechanical flocculator with four flocculation chambers, hydrodynamic tests were conducted using sodium chloride as a tracer resulting in curves of the residence time distribution (RTD) and the mean residence times for the theoretical residence time of 29.54 min, 22.15 min and 14.77 minutes, respectively for the flocculator with 04, 03 and 02 chambers. Between the flocculation chambers had four different positions of passages, two on top D and E (respectively upper right and upper left) and two down d and e (respectively lower right and lower left). Taking into account that the entry of water has always been held in the lower left passage “e” for the flocculator with 04 chambers, four different configurations were combined (eEeEe, eDeDe, edede and eeeee) and a fifth employing shields (e/e/e/e/e). The same settings were extended to the flocculator operating with three and two chambers. Was evaluated in flocculation unit, operating under the different configurations of passage, the magnitude of the effects of short circuits according to the studies previously defined. These studies combined the direction of rotation of the agitator with the velocity gradient and a study of the rioters off. Was observed after analysis of the curves RTD, that the settings edede and e/e/e/e/e to flocculators of 04, 03 and 02 chambers, showed a lower incidence of short-circuits that configuration eEeEe. The placement of the bulkhead, which generated the configuration e/e/e/e/e, showcases itself as an efficient alternative only in the absence of agitation, promoted by agitators. Flocculator with 04 chambers, one does not notice the influence of parameters direction of the agitator and the constancy or variation of velocity gradient on the RTD

Resumo: Esse estudo investigou a cinética de coagulação floculação do TiO2 em suspensão aquosa de baixa força iônica (água destilada)e força iônica média (água de abastecime to público),em função do pH e da adição de sulfato de alumínio. A coagulação floculação do TiO2 ocorre quando o pH é ajustado próximo ao pH do potencial isoelétrico, pela compressão da camada de difusão ou pela adsorção hidrólise com íons Al 3+ . Em suspensões de TiO2 com baixa força iônica,a coagulação ocorre a um determinado pH (4,0 e 7,0), uma vez que ele depende basicamente da superfície do óxido. Com adição de um coadjuvante de sedimentação (por ex. sulfato de alumínio), a qual a força iônica é alta,a coagulação floculação ocorre muito rápido. O tempo de decantação do material em suspensão foi de 2:00 h, foi comparada a cinética de sedimentação da decantação simples com a realizada em Jar Test sob a influência de agitação rápida (eletrocinético) e lenta (ortocinético) antes de permitir a sedimentação. O melhor desempenho foi em Jar Test,turbidez final de 10 NTU. / Abstract: This study investigated the coagulation-flocculation kinetics of TiO2 in an aqueous Suspension of low-strength ionic solution (distilled water) and a medium strength ionic solution (tap water) as a function of pH and of the addition of aluminum sulfate. Coagulation-flocculation of TiO2 occurs when the pH is adjusted close to the isoelectric potential (iep), by compression of the diffusion layer or by adsorption-hydrolysis with Al 3+ ions. In TiO2 suspensions with low electric strength,coagulation takes place at certain pH (4,0 a d 7,0) since it depends basically on the oxide surface.With the addition of sedimentation aid (e.g.,aluminum sulfate), in which the ionic strength is high, coagulation-flocculation, takes place very fast. The decantation time of the material in suspension was of 2h. The sedimentation kinetic of the simple decantation was compared to that carried out in Jar Test under influence of fast stirring (electrokinetic) and slow stirring (ortokinetic) before sedimentation set up.The best performance was in Jar Test,final turbidez of 10 NTU. / Orientador: Ariovaldo de Oliveira Florentino / Coorientador: José Pedro Serra Valente / Banca: Pedro Magalhães Padilha / Banca: Cassio Luis Fernandes de Oliveira / O Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi da Unesp / Mestre

The quality of water within an estuary is inseparable from the component parts; suspended particulate matter (SPM) and the balance of macro-nutrients. Long-term temporal variations and the horizontal advection of both SPM and macro-nutrient concentrations are well-constrained, but the vertical fluxes associated with micro-scale processes, such as turbulence and flocculation, are poorly constrained. The importance of three micro-scale processes on the interactions between SPM and inorganic macro-nutrients, nitrate (NO–3 ), ammonium (NH+4) and phosphate (PO3 –4 ), are examined in four field campaigns and five laboratory experiments. Field campaigns were conducted in two turbid estuaries. One field campaign was conducted in the Seine estuary, France, and three campaigns in the Tamar estuary, U.K., in order to consider the effects of seasonal variations (spring, summer and autumn). Physical conditions measured included current velocity, turbidity, turbulence and particle size, were recorded using a suite of oceanographic instrumentation. Five different laboratory studies were conducted using the same mini annular flume, with different background conditions. Inorganic macro-nutrients were measured spectrophotometrically on a continuous flow analyser (for NO – 3 and PO3 –4) and fluorimetry (NH +4). Three hypotheses are presented as potential mechanisms controlling the release and uptake of macro-nutrients from sediments. Mechanism One (M1) described an exchange process between inorganic macro-nutrients and flocculation/disaggregating particles. It was hypothesised that flocculating particles would decrease water column macro-nutrient concentrations, and vice versa. In this study, flocculation was observed in both field sites, but there was no significant relationship between flocculation and macro-nutrient concentration. Similarly, the five laboratory studies demonstrated no statistically significant relationships between flocculation and macro-nutrient concentrations. Mechanism Two (M2) hypothesised that turbulence would enhance the release portion of the exchange processes described in M1. Furthermore, it was proposed that increased turbulence would break bonds between macro-nutrients and the surface of particle faces. Turbulence was observed to limit the floc size in all experiments (both field and laboratory), but this study determined that it did not promote a significant release mechanism for inorganic macro-nutrients. However, this study observed that turbulence played a key role in the vertical distribution of PO 3 – 4 and NH +4. In both the Seine and Tamar estuaries, surface and near-bed concentrations were observed to be statistically significantly different (p = < 0.05). Finally, Mechanism Three (M3) hypothesised that increased salinity provides additional salt water cations that would enhance flocculation and M1. This study measured an increase in floc size with increasing salinity in but did not enhance the proposed M1. Instead, as with turbulence, differences in water density as a result of the salinity affected the vertical distribution of NO –3. This research concluded that micro-scale processes have no significant impact on the water-column concentration of inorganic macronutrients. Instead, it was observed that two of the three micro-scale processes, turbulence and salinity, play a key role in the vertical distribution of inorganic macro-nutrients in the Tamar and Seine estuaries.

Orientador: Rodrigo Braga Moruzzi / Banca: Sidney Seckler Ferreira Filho / Banca: André Luiz de Oliveira / Banca: Samuel Conceição de Oliveira / Banca: Maria da Graça Bontempo Vaz Rasteiro / Resumo: Este trabalho visa estabelecer um procedimento para a obtenção de parâmetro cinético de agregação por método direto e dinâmico, livre de distúrbios analíticos significativos, como a sedimentação de partículas e com resultados obtidos através do auxílio do equipamento PDA (Photometric Dispersion Analyser) juntamente com técnica que utiliza análise digital de imagem com dados tratados por software específico. A modelagem do processo foi realizada por meio da adaptação da modelagem clássica de agregação e ruptura com vistas à obtenção dos parâmetros cinéticos do processo de floculação diretamente no início da etapa de agregação das partículas que ocorre nos primeiros segundos do processo de floculação. Foi possível estabelecer uma relação entre a resposta do equipamento PDA e apenas o crescimento no diâmetro dos agregados formados no início do processo de floculação, informação obtida por meio de técnica de análise de imagem, assim possibilitando a correlação entre ambos os parâmetros e obtenção do coeficiente de agregação do modelo cinético. Os resultados da pesquisa auxiliam no entendimento do fenômeno e do processo de floculação, etapa essa fundamental para o desempenho de sistemas de tratamento de água para abastecimento / Abstract: This work aims to establish a procedure for obtaining a kinetic parameter of aggregation by direct and dynamic method, free of significant analytical disturbances, such as particle sedimentation and with results obtained through the aid of PDA (Photometric Dispersion Analyzer) equipment together with technique that uses digital image analysis with data processed by specific software. The process modeling was performed by adapting the classical aggregation and rupture modeling to obtain the kinetic parameters of the flocculation process directly at the beginning of the particle aggregation step that occurs in the first seconds of the flocculation process. It was possible to establish a relationship between the response of the PDA equipment and only the growth in the diameter of the aggregates formed at the beginning of the flocculation process, information obtained by image analysis technique, thus enabling the correlation between both parameters and obtaining the coefficient. of aggregation of the kinetic model. The results of the research help in understanding the phenomenon and the flocculation process, a step that is fundamental for the performance of water treatment systems for water supply / Doutor

Due to the flocculation process, suspended mud aggregates carried by rivers and streams can undergo changes in their size, shape, and settling velocity in response to environmental drivers such as turbulence, sediment concentration, organic matter (OM), and salinity. Some have assumed that salt is necessary for floc formation, and that mud, therefore, reaches the estuary unflocculated. Yet mud flocs exist in freshwater systems long before the estuarine zone, likely due to the presence of OM and ions in the water that facilitate binding and aggregation of mud particles. This research aimed to examine the flocculation state of mud over the fluvial as well as fluvial to marine transition (FtMT) zones of the Mississippi River basin and how salinity, or the ion concentration of water, and organic matter independently and together affect flocculation. Suspended mud was found to be mostly flocculated in the headwaters of the Mississippi River in southwest Virginia, USA. However, increasing the ion concentration of water samples to levels measured following winter storms changed the size distribution of suspended particles, led to more of the mud existing in large flocs, and resulted in an overall increase in average size by about 40%, thereby increasing the settling rate of the mud relative to the suspensions without salt. These results suggested that potential negative effects of road salts on mud deposition should be investigated further. Additional experiments were used to examine the flocculation of a natural mud sample with and without OM showed that the rate of floc growth and equilibrium size both increase with salinity regardless of the presence or absence of OM. However, the response of both to salinity was stronger when OM was present. In deionized water, natural sediment with OM was seen to produce large flocs. However, the size distribution of the suspension tended to be bimodal. With the addition of salt, increasing amounts of unflocculated material became bound within flocs, producing a more unimodal size distribution. Here, the enhancing effects of salt were noticeable at even 0.5 ppt, and increases in salinity past 3 to 5 ppt only marginally increased the floc growth rate and final size. A salinity-dependent model to account for changes in floc growth rate and equilibrium size was presented. Laboratory experiments on the sediment suspended in the lower reaches of the Mississippi River were used to provide further insight on the mud flocs behavior in the FtMT. Turbulence shear rate, a proxy for the river hydrodynamics, was found to be the most influential factor in mud floc size. While artificial increase in salinity by adding of salts did not lead to considerable increase in floc size, addition of water collected from the Gulf of Mexico enhanced the flocculation. These effects were speculated to originate from the biomatter composition of the Gulf water, particularly where the nutrient-rich Mississippi River water reaches the marine water. / Doctor of Philosophy / Rivers bring a substantial amount of mud to coastal regions. Where this mud deposits is important in shaping the coastal land and nutrient dynamics. Mud particles are different from sand and gravel in that they can form aggregates known as flocs that constantly change shape and size under different conditions. As they change size, they change how fast they sink, and this influences where they deposit. Due to their small size, mud particles are also considered a pollutant as they can clog up fish gills and destroy freshwater habitats. Findings of this dissertation showed that the roadway deicing salts that make their way to streams can enhance the aggregation of mud particles, causing them to sink faster. This can be harmful to the species that live on streambeds. While salts are known to enhance flocculation, there is ample evidence that flocs exist in rivers before reaching the sea. It is possible, therefore, that flocs in estuaries are due to biological matter acting as a glue to bind mud particles together and may not be influenced by salt. This dissertation looked at the effects of saltwater on mud flocculation when biological matter is present and when it is absent. Findings showed that salinity increased the size of mud flocs, even more so than when organic matter was absent. However, organic matter was needed for flocs to reach sizes often found in nature. An equation was also provided to aid in the prediction of floc size under different salinities. Observations on the lower Mississippi River flocs showed that the turbulence of water was the most influential factor in determining the size of flocs.

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Yes / Sedimentation processes are fundamental to solids/liquid separation in water and wastewater treatment, and therefore a robust understanding of the settlement characteristics of mass fractal aggregates (flocs) formed in the flocculation stage is fundamental to optimized settlement tank design and operation. However, the use of settling as a technique to determine aggregates’ traits is limited by current understanding of permeability. In this paper, we combine experimental and numerical approaches to assess settling velocities of fractal aggregates. Using a non-intrusive in situ digital image-based method, three- and two-dimensional fractal dimensions were calculated for kaolin-based flocs. By considering shape and fractal dimension, the porosity, density and settling velocities of the flocs were calculated individually, and settling velocities compared with those of spheres of the same density using Stokes’ law. Shape analysis shows that the settling velocities for fractal aggregates may be greater or less than those for perfect spheres. For example, fractal aggregates with floc fractal dimension, Df ¼ 2.61, floc size, df > 320 μm and dp ¼ 7.5 μm settle with lower velocities than those predicted by Stokes’ law; whilst, for Df ¼ 2.33, all aggregates of df > 70 μm and dp ¼ 7.5 μm settled below the velocity calculated by Stokes’ law for spheres. Conversely, fractal settling velocities were higher than spheres for all the range of sizes, when Df of 2.83 was simulated. The ratio of fractal aggregate to sphere settling velocity (the former being obtained from fractal porosity and density considerations), varied from 0.16 to 4.11 for aggregates in the range of 10 and 1,000 μm, primary particle size of 7.5 μm and a three-dimensional fractal dimension between 2.33 and 2.83. However, the ratio decreases to the range of 0.04–2.92 when primary particle size changes to 1.0 μm for the same fractal dimensions. Using the floc analysis technique developed here, the results demonstrate the difference in settlement behaviour between the approach developed here and the traditional Stokes’ law approach using solid spheres. The technique and results demonstrate the improvements in understanding, and hence value to be derived, from an analysis based on fractal, rather than Euclidean, geometry when considering flocculation and subsequent clarification performance / Rodrigo B. Moruzzi is grateful to São Paulo Research Foundation (Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP) Grant 2017/19195-7 for financial support and to CNPq for the fellowship Grant 301210/2018-7.

The activated sludge wastewater treatment process depends upon the formation of biological floc for effective liquid-solids separation, nutrient stabilization and sludge dewatering. Continued research into floc formation, intrafloc interactions and floc hydrodynamics is necessary for improved understanding of the activated sludge process.The overall goal of this research program was to investigate laser-based methods for characterizing biological flocs. The research objectives included the selection of laser-based methods which are applicable to the wastewater treatment plant environment, design and development of laser-based instrument configurations, measurement of particles with known characteristics, measurement of activated sludge samples and determination of the factors affecting laser-based instrument operation. / Master of Science