Neste trabalho estudou-se o pós-tratamento de efluente de lagoa anaeróbia e lagoa facultativa por processo físico-químico à base de coagulação, floculação e separação sólido-líquido. A motivação principal para o desenvolvimento da pesquisa foi a dificuldade que os sistemas de lagoas de estabilização apresentam para atender aos limites de qualidade da água impostos pela Resolução Nº 357/2005 do CONAMA para os corpos receptores. Os efluentes de lagoa anaeróbia e lagoa facultativa utilizado nesta pesquisa são provenientes da Estação de Tratamento de Esgoto de Lins-SP. Para o pós-tratamento utilizou-se um sistema de fluxo contínuo, em escala piloto, de coagulação, floculação e decantação lamelar ou flotação com ar dissolvido para a separação de sólidos, determinando-se dosagens prévias de sulfato de alumínio ou cloreto férrico em ensaios em escala de laboratório. Após a escolha da dosagem a ser trabalhada em escala piloto, foram feitas seis repetições para cada dosagem, variando o tipo de efluente, o tipo de coagulante, o processo de separação sólido-líquido. Através dos processos testados foi possível remover fósforo de forma a obter-se concentração da ordem de 1,0 mg P/L. Utilizando a dosagem de 24 mg Al/L no tratamento do efluente da lagoa facultativa, este processo obteve os melhores resultados de remoção de DQO, SST, Clorofila a e coliformes, além de ter apresentado bons resultados de remoção de fósforo. O pós-tratamento físico-químico aplicado ao efluente da lagoa anaeróbia também apresentou boa eficiência na remoção de fósforo, na utilização do sulfato de alumínio tanto na flotação quanto na sedimentação atingiu valores em torno de 0,2 mg P/L. Este estudo permite ainda concluir que o tratamento do efluente da lagoa anaeróbia por processo físico-químico é mais eficiente com relação a remoção de fósforo e menos oneroso que se aplicado ao efluente da lagoa facultativa. Porém a maior eficiência na remoção de DQO e patogênicos ocorreram no pós-tratamento do efluente da facultativa. / It was studied in this paper the anaerobic and facultative pond effluent post-treatment through physico-chemical process based on coagulation, flocculation and solid-liquid separation. The main motivation to develop such research was the difficulty that the stabilization pond systems present to be in accordance with the limits of water quality imposed by Resolution number 357/2005 of Brazilian Federal Environmental Council Legislation to receiving bodies. The anaerobic and facultative pond effluents used in this survey come from Sanitary Wastewater System from Lins-SP. For post-treatment was used a continuous flow system, in a pilot scale of coagulation, flocculation and multiple-tray clarification or dissolved air flotation to separate solids, by determining previous dosages of alum or ferric chloride in experiences in laboratory scale. After the dosage choice to be worked in a pilot scale were made six repetitions for each dosage, varying the effluent type, the kind of coagulant and solid-liquid separation process. Through tested processes it was possible a phosphorus removal in order to get a concentration around 1,0 mg P/L. By making the use of 24 mg Al/L dosage on the facultative pond effluent treatment this process got the best removal results of COD, TSS, chlorophyl A and coliforms, yet having presented good results on phosphorus removal. The physico-chemical post-treatment given to anaerobic pond effluent also presented a good efficiency regarding to phosphorus removal, by using alum both in the flotation and sedimentation reached values around 0,2 mg P/L. This search also allows us to conclude that the anaerobic pond effluent treatment through physicochemical process is more efficient relating to phosphorus removal and less harmful than that applied to facultative pod effluent. But, the greatest efficiency on COD and pathogenic removal occurred in the facultative effluent post-treatment.

Neste trabalho estudou-se o pós-tratamento de efluente de lagoa anaeróbia e lagoa facultativa por processo físico-químico à base de coagulação, floculação e separação sólido-líquido. A motivação principal para o desenvolvimento da pesquisa foi a dificuldade que os sistemas de lagoas de estabilização apresentam para atender aos limites de qualidade da água impostos pela Resolução Nº 357/2005 do CONAMA para os corpos receptores. Os efluentes de lagoa anaeróbia e lagoa facultativa utilizado nesta pesquisa são provenientes da Estação de Tratamento de Esgoto de Lins-SP. Para o pós-tratamento utilizou-se um sistema de fluxo contínuo, em escala piloto, de coagulação, floculação e decantação lamelar ou flotação com ar dissolvido para a separação de sólidos, determinando-se dosagens prévias de sulfato de alumínio ou cloreto férrico em ensaios em escala de laboratório. Após a escolha da dosagem a ser trabalhada em escala piloto, foram feitas seis repetições para cada dosagem, variando o tipo de efluente, o tipo de coagulante, o processo de separação sólido-líquido. Através dos processos testados foi possível remover fósforo de forma a obter-se concentração da ordem de 1,0 mg P/L. Utilizando a dosagem de 24 mg Al/L no tratamento do efluente da lagoa facultativa, este processo obteve os melhores resultados de remoção de DQO, SST, Clorofila a e coliformes, além de ter apresentado bons resultados de remoção de fósforo. O pós-tratamento físico-químico aplicado ao efluente da lagoa anaeróbia também apresentou boa eficiência na remoção de fósforo, na utilização do sulfato de alumínio tanto na flotação quanto na sedimentação atingiu valores em torno de 0,2 mg P/L. Este estudo permite ainda concluir que o tratamento do efluente da lagoa anaeróbia por processo físico-químico é mais eficiente com relação a remoção de fósforo e menos oneroso que se aplicado ao efluente da lagoa facultativa. Porém a maior eficiência na remoção de DQO e patogênicos ocorreram no pós-tratamento do efluente da facultativa. / It was studied in this paper the anaerobic and facultative pond effluent post-treatment through physico-chemical process based on coagulation, flocculation and solid-liquid separation. The main motivation to develop such research was the difficulty that the stabilization pond systems present to be in accordance with the limits of water quality imposed by Resolution number 357/2005 of Brazilian Federal Environmental Council Legislation to receiving bodies. The anaerobic and facultative pond effluents used in this survey come from Sanitary Wastewater System from Lins-SP. For post-treatment was used a continuous flow system, in a pilot scale of coagulation, flocculation and multiple-tray clarification or dissolved air flotation to separate solids, by determining previous dosages of alum or ferric chloride in experiences in laboratory scale. After the dosage choice to be worked in a pilot scale were made six repetitions for each dosage, varying the effluent type, the kind of coagulant and solid-liquid separation process. Through tested processes it was possible a phosphorus removal in order to get a concentration around 1,0 mg P/L. By making the use of 24 mg Al/L dosage on the facultative pond effluent treatment this process got the best removal results of COD, TSS, chlorophyl A and coliforms, yet having presented good results on phosphorus removal. The physico-chemical post-treatment given to anaerobic pond effluent also presented a good efficiency regarding to phosphorus removal, by using alum both in the flotation and sedimentation reached values around 0,2 mg P/L. This search also allows us to conclude that the anaerobic pond effluent treatment through physicochemical process is more efficient relating to phosphorus removal and less harmful than that applied to facultative pod effluent. But, the greatest efficiency on COD and pathogenic removal occurred in the facultative effluent post-treatment.

Only a few studies have looked at microbial biogeography in soils and whether microorganisms are endemic to an area is still debatable. Tramway Ridge, a geothermal area on Mount Erebus, Antarctica, provides a unique opportunity due to its isolation and extreme conditions to explore the possibilities of microbial endemism and to identify novel Bacteria and Archaea. This site was chosen for a culture-independent study with a preliminary culturing survey for bacterial communities along three temperature gradients (65 C - 2.5'C). In addition, a physico-chemical analysis was undertaken to identify which environmental factors were driving the different diversity along the transects. An automated rRNA intergenic spacer analysis (ARISA) was used to assess the diversity across the transects using Bacteria and Cyanobacteria-specific primers and results showed that temperature and pH were the main drivers for these communities. Due to its unique physico-chemical and ARISA profile, a hot temperature site (T-3A, 65'C) was chosen for further investigation by bacterial and archaeal 16S rDNA clone libraries. Unique rDNA types among the 78 bacterial and 83 archaeal clones were identified by restriction fragment length polymophisms and 18 bacterial and 5 archaeal operational taxonomic units (gt97% identity) were observed. All of the bacterial sequences were deeply branching and loosely affiliated with other recognised bacterial divisions, with 40% of the sequences not affiliated to any genus. The archaeal clones were found to be deep-branching and sequences clustered together within the Crenarcaheota. In addition, two strains of Bacilli were isolated. The novel microorganisms show that the Tramway Ridge communities are unique from organisms found in other environments and show that quotEverything is (not) everywherequot.

The present study focuses on the analysis of physico-chemical parameters: electrical conductivity, nitrate and phosphate in the Akaki River basin of Addis Ababa, Ethiopia. These secondary water quality parameters were obtained from two different sources: the surface water quality data both for Little and Great Akaki were retrieved from Addis Ababa Environmental Protection Agency (AAEPA). Whereas, the groundwater quality data for four water wells were obtained from Addis Ababa Water and Sewerage Authority (AAWSA). These water quality parameters have been determined in order to assess the pollution levels of Akaki River basin. The values of the parameters have been evaluated with respect to the maximum acceptable standard level of WHO (World Health Organization) for surface and drinking water. The outcome of the study observed absence of spatial and temporal pattern both on surface and groundwater but displayed a huge variation. The result also showed increasing concentration and variation of all parameters inside and outside the city of Addis Ababa with increasing industrialization and urbanization. Comparison also showed that the little Akaki is highly polluted as compared to Great Akaki River. The ground water chemistry also showed a high phosphate load in all of the productive wells. On the contrary, all the wells displayed nitrate level below WHO standard and they are free from Nitrate. KEY WORDS: Addis Ababa, Ethiopia, Physico-chemical, Little and Great Akaki, AAEPA, AAWSA, Spatial, temporal.

Cette thèse traite de l'étude du comportement du contact disque-garniture sous sollicitations sévères de freinage rencontrées lors de freinages d'arrêt d'urgence ou de successions de freinages rapprochés avec cumul de chaleur. L'approche adoptée est multiphysique par la prise en compte des interactions entre tribologie, thermique et physicochimie, et l'étude est présentée en 4 parties.<br />La première présente la caractérisation des matériaux étudiés (un matériau composite à matrice organique et une fonte GL) et les moyens expérimentaux utilisés.<br />La seconde concerne la dégradation du matériau composite avec la température et l'influence de cette dégradation sur le comportement tribologique du couple de matériaux et les mécanismes physiques de frottement activés au contact.<br />La troisième présente l'étude du comportement en freinage du contact disque-garniture sous les deux types de sollicitations sévères. Les évolutions du coefficient de frottement sont corrélées aux phénomènes de localisation thermique de surface observés par thermographie infrarouge et aux mécanismes physiques identifiés à partir d'observations et d'analyses des surfaces après freinage.<br />La quatrième est dédiée à l'étude de l'évolution des mécanismes physiques de frottement activés pendant un freinage d'arrêt isolé à haute énergie et de leur interaction avec les phénomènes thermiques locaux et transitoires observés en surface. Des observations et des analyses de surfaces sont menées après des freinages interrompus avant l'arrêt à des instants typiques du freinage. Des observations in-situ de la piste de frottement du disque en vidéo rapide permettent d'appuyer les résultats déduits des observations post-mortem.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Le dioxyde de titane, composé minéral très utilisé dans les produits cosmétiques de protection solaire, est depuis peu incorporé sous forme de nanoparticules, ce qui suscite des interrogations sur les risques sanitaires induits. Nous avons élaboré un protocole d’émulsions huile-dans-eau permettant l’incorporation de nanoparticules de TiO2 à différents pourcentages (2,5-10%) et présentant deux traitements de surface hydrophobes distincts : un coating hybride isopropyl titanium triisostearate / triethoxycaprylylsilane et un coating triethoxycaprylylsilane. L’incorporation des nanoparticules permet de conserver la structure microscopique de l’émulsion et dans le même de temps de renforcer les propriétés rhéologiques. Les analyses physico-chimiques ont montré que l'état de floculation initial des émulsions est coating-dépendant. A 50°C, les émulsions se déstabilisent au cours du temps jusqu’à une agrégation très marquée des nanoparticules, et ce moins rapidement pour le coating hybride. Les formulations avec et sans nanoparticules sont légèrement cytotoxiques, avec un effet plus marqué pour les fortes concentrations en TiO2 et après vieillissement de 40 jours à hautes températures. Nous avons démontré que l’état de surface des nanoparticules extraites des formulations est modifié au cours du vieillissement par une adsorption de certains constituants de l’émulsion à la surface des nanoparticules. Ces nanoparticules modifiées sont plus cytotoxiques que les nanoparticules brutes. Les mécanismes de vieillissement induisent donc la libération de résidus de nanomatériaux plus toxiques que leur état initial, et pourraient conduire à un risque sanitaire pour l'homme l'environnement. / Titanium dioxide, the most commonly used mineral compound in cosmetic sunscreen products, has recently been incorporated in the form of nanoparticles, which raises health issues. We have developed a protocol of oil-in-water emulsions that enables the incorporation of different amount (2.5-10%) of TiO2 nanoparticles coated with two distinct hydrophobic surface treatments: an isopropyl titanium triisostearate / triethoxycaprylylsilane hybrid coating and a triethoxycaprylylsilane coating. The incorporation of nanoparticles preserves the microscopic structure of the emulsion while enhancing the rheological properties. Physico-chemical analyses showed that the initial state of flocculation of the emulsions is coating-dependant. At 50°C, emulsions destabilize over time until a strong aggregation of nanoparticles, in a delayed way for the hybrid coating. Formulations with and without nanoparticles appear slightly cytotoxic, with an enhanced effect for high amount of TiO2 and for a 40 days aging at high temperatures. We have shown that the surface of nanoparticles extracted from the formulations has been modified during aging, due to an adsorption of chemicals of the emulsion to the nanoparticle surface. Such modified nanoparticles become more cytotoxic if compared to raw nanoparticles. Aging mechanisms can therefore release nanomaterials residues with an increased toxic activity compared to their initial state, and thus could lead to health hazard for humans and for the environment.

Les outils d’analyse actuellement utilisés pour caractériser la dégradation multi-échelle du béton par la réaction alcali-silice (RAS) présentent certaines limites manifestes à un diagnostic précis : à l’échelle macroscopique, ils montrent généralement une faible sensibilisé à la microfissuration progressive du béton ; aux échelles microscopique et mésoscopique, le recours systématique à la microscopie limite la représentativité et la quantification des observations réalisées. Cette thèse propose d’évaluer la contribution de paramètres physico-chimiques (mesure de l’altération de la silice réactive) et non destructifs (caractérisation du comportement élastique non linéaire du béton) vis-à-vis de la détection et de la quantification des dommages causés dans le béton par la RAS. Des essais réalisés sur des bétons fabriqués en laboratoire et contenant du calcaire Spratt ont mis l’accent sur l’intérêt des paramètres proposés pour la détection précoce de la RAS dans le béton : les analyses physico-chimiques ont permis d’apporter des informations quantitatives sur les variables d’avancement de réaction qui se caractérisent par une augmentation du taux de silanols et du volume apparent de la silice réactive ; la microfissuration générée par le gonflement du squelette granulaire a pu être suivie par le paramètre non linéaire de décalage fréquentiel avec une sensibilité plus de dix fois supérieure à celle des paramètres linéaires (propriétés mécaniques, acoustique linéaire). Une étude réalisée sur des carottes extraites d’un ouvrage en service (essais d’expansion résiduelle) valide l’applicabilité des méthodes pour un cas d’étude réel. / Monitoring tools currently used to characterize multi-scale degradation of concrete by alkali-silica reaction (ASR) show some obvious limitations to an accurate diagnosis. Macroscopic scale tools usually show a low sensitivity to progressive microcracking in concrete. From microscopic and mesoscopic points of view, the systematic use of microscopy limits the representativeness and quantification of observations made. This thesis evaluates the contribution of physicochemical parameters (deterioration of the reactive silica) and non-destructive testing (characterization of nonlinear elastic behaviour of concrete) for detecting and quantifying deterioration caused by ASR in concrete. A laboratory study on concrete containing Spratt limestone as coarse aggregate was performed to compare the physicochemical and nonlinear parameters to more commonly used ones for ASR damage assessment (swelling of concrete, petrographic examination, compressive strength, tensile strength, static and dynamic modulus of elasticity, ultrasonic pulse velocity). Physicochemical analysis allowed to measure early impairment of reactive silica, quantified by an increasing quantity of silanols and an increase of its apparent volume. The microcracking caused by the granular skeleton swelling could be monitored by the frequency shift linear parameter with a ten times higher sensitivity than linear parameters. Tests were also performed on concrete samples extracted from a lock affected by ASR (with reactive aggregate similar to Spratt limestone) and allowed to confirm the interest of the proposed parameters on a real case study.

Traditionally, barley is the preferred cereal for traditional lager brewing. The use of sorghum for the production of European-style lager beers has recently been recognised. The use of sorghum as brewing adjunct could be a major socio-economic advantage in the developing countries in Africa. Limitations for its use, however, include its low amylolytic potential, high gelatinization temperatures, and the presence of tannins. Adjuncts are often combined with cereal malt during the brewing process to provide extra sources of fermentable carbohydrates. As with all cereals, the functional properties of sorghum grains are influenced by their physico-chemical characteristics. It is therefore critical to understand the structure, chemistry and functionality of the sorghum cultivar(s) considered for use as brewing adjuncts. Hot water extract describes the quality of the wort of an adjunct and depicts the amount of starch that was solubilised during mashing. The determination of hot water extract is expensive, laborious and time-consuming. The provision of a possible predictive marker(s) for sorghum hot water extract that is less complicated to determine, could be of great economical value to the brewer. Hot water extract was determined for 43 sorghum cultivars and then compared to various physico-chemical characteristics. Sorghum endosperm texture was visually determined. Suspensions of whole sorghum flour were pasted using a Rapid Visco Analyser (RVA) with an extended heating cycle. Significant negative correlations were obtained between extract content and pasting temperature and time in corneous endosperm samples. There was also a significant positive relationship between tannin-free sorghums and peak viscosity in pasted samples. Protein contents of 10 different sorghums were compared to their hot water extracts, where there was a significant negative relationship between these characteristics. Protein content could be used successfully as a predictive marker for extract. No significant relationship could be established between sorghum hot water extract and starch content. Tannin-containing sorghum cultivars gave significantly lower extracts and had higher malt diastatic power (DP) than non-tannin cultivars. There was no significant relationship between the DP and extract content of non-tannin sorghums. When only non-tannin sorghum cultivars that pasted were subjected to principal component analysis, it seemed that a positive relationship existed between peak viscosity and extract content. Low protein sorghum cultivars with no tannins and corneous endosperm would be suitable for use as brewing adjuncts. Protein content, the presence of tannins, endosperm texture and peak viscosity could be used as predictive markers for sorghum hot water extract / Dissertation (MSc(Agric))--University of Pretoria, 2011. / Food Science / unrestricted

<p> The effect of low temperature on the physico-chemical treatment (PCT) of domestic wastewater is examined with special emphasis placed on activated carbon adsorption. PCT is a recent processing scheme, wherein wastewater goes through sedimentation, precipitation, deep bed filtration and adsorption. In PCT, activated carbon adsorption takes the place of conventional biological treatment for organic removal.</p> <p> Both batch studies using powdered activated carbon (PAC) and continuous flow studies with granular activated carbon (GAC) on a pure compound, sodium dodecyl sulfate (SDS) and domestic wastewater from the Dundas, Ontario Water Pollution Control Plant were investigated.</p> <p> Theoretical analysis and batch feasibility studies indicate that the effect of low temperature on coagulation, flocculation and sedimentation were quite easily handled within established design parameters. Batch studies on PAC treatment show that the carbon floc is easily separable from wastewater with the aid of a small dosage of polyelectrolyte and high effluent quality is obtainable at temperatures ranging from 2° - 25°C.</p> <p> Granular activated carbon was evaluated first on a pure compound, SDS. Batch isotherms and kinetics were also conducted at the same time to determine parameters needed for continuous flow modelling. Results derived from this phase of the study indicate that the activation energy from column studies is quite low (approximately 3.0 kcal/mole). Close match is obtained between the theoretical model (a modification of Thomas' reaction kinetics) and experimental data.</p> <p> Finally PCT pilot plant studies on domestic wastewater were carried out, at 5°C and 25°C. Soluble organic carbon removal was in excess of that predicted by purely adsorption type phenomenon. This is attributed to microbial activity inside the carbon columns. Greater soluble organic removal was seen at 25°C than at 5°C. Denitrification inside the carbon columns was found to be quite significant, again with stronger denitrifying activity at 25°C than at 5°C. Microbiological investigation of the carbon from the exhausted columns revealed over 10^9 cells/cm^3) of GAC bed volume from the lead column at 25°C. Denitrifiers were also detected in the carbon. Iodine numbers were determined on used carbon, which indicated the exhaustion of activated carbon capacity. Organic removal, however, continued undiminished, due to bacterial activity.</p> <p> The study culminated with the development of a theoretical model incorporating bacterial activity. The results of column effluent profile, however, indicated great discrepancy between theoretical predictions and experimental observations. This was attributed to simplistic assumptions utilized in solving the fixed bed problem.</p> / Thesis / Master of Engineering (MEngr)