• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 10
  • 4
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 27
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Índice de perigo para subsidiar a aplicação de lodo de esgoto em solo agrícola / Hazard index for the decision-making process of sludge agricultural use

Marcus Emmanuel Mamana da Matta 12 August 2011 (has links)
A ampliação dos sistemas de tratamento de esgoto sanitário implica diretamente no aumento da geração de lodos de esgoto, que precisam ser adequadamente dispostos. Devido aos benefícios agronômicos, a incorporação de lodo de esgoto em solo agrícola tem sido, em diversos países, a forma mais sustentável para aproveitamento deste resíduo. A Resolução Conama 375 de 2006 normatiza essa prática no Brasil, e os critérios para a tomada de decisão quanto a ocorrência de poluentes químicos no lodo de esgoto se restringe a determinação de onze compostos inorgânicos, o que gera preocupação em relação a outros compostos presentes na matriz e que podem proporcionar riscos ao ecossistema e à saúde humana. Para complementar a avaliação de matrizes complexas como lodo de esgoto, efluentes, sedimentos, solos contaminados, se tem preconizado o uso de testes de toxicidade, os quais fornecem evidências do perigo da mistura como um todo. O objetivo da tese foi desenvolver um índice para avaliar a periculosidade de lodo de esgoto, utilizando ensaios ecotoxicológicos de curta duração e baixo custo, com objetivo de subsidiar decisões mais rápidas quanto a sua aplicação em solo agrícola. O Índice de Perigo de Lodo de Esgoto (IPLE) integrou os resultados de teste de ecotoxicidade com Vibrio fischeri, Daphnia similis e teste de inibição do alongamento de raiz e da germinação de sementes. A fórmula do IPLE desenvolvido foi: log natural de um somado ao número de testes positivos, multiplicado pela ecotoxicidade média obtida nos testes, convertidos em unidade tóxica. O IPLE foi calculado utilizando os dados publicados pela CETESB de caracterização química e ecotoxicológica de 28 amostras de lodo de esgoto coletadas em 7 Estações de Tratamento de Esgoto (ETE) do Estado de São Paulo. O IPLE foi testado pela avaliação do percentual de amostras não conformes por faixa de índice, considerando para tanto os limites de substância química estabelecidos em diferentes normas de uso agrícola de lodo. As amostras com IPLE acima de 2 (n=15) apresentaram maior frequência de não conformidade quando comparado com as amostras com índice abaixo de 2 (n=13). O IPLE parece ser um bom indicador preliminar do perigo de amostras de lodo de esgoto, sugerindo reprovação e aprovação precoce de seu uso agrícola e como instrumento para acompanhamento e gestão da qualidade do lodo e comunicação de perigo / The expansion of urban wastewater treatment plants increases the generation of sewage sludge, that must be properly disposed. Due to the agronomic benefits, the incorporation of sewage sludge on agricultural land has been in several countries, the most sustainable use of this waste. CONAMA Resolution 375 of 2006 regulates the practice in Brazil, and the criteria for chemical pollutants in the sewage sludge are based on the concentration of eleven inorganic compounds, which raises concern in relation to other compounds present in matrix that could provide risk to the ecosystem and human health. Ecotoxicology evaluation of complex samples as sewage sludge, wastewater, sediments, contaminated soils, has been often recommended to provide evidence of the whole mixture. The aim of this thesis was to develop a Sewage Sludge Hazard Index (SSHI) based on short term and low cost bioassays, to be a complementary tool for the decisionmaking process of sewage sludge application to agricultural land. SSHI integrated results from Vibrio fischeri, Daphnia similis and seed elongation/germination test. Sewage Sludge Hazard Index (SSHI) was calculated as the natural logarithm of one plus the number of positive toxic responses multiplied by the average of the toxic units obtained in each bioassay. The index was calculated using data generated by CETESB from chemical and ecotoxicological characterization of 28 samples collected in 7 different wastewater treatment plants (WWTP) of Sao Paulo State. SSHI was tested by assessing the percentage of samples non-compliances for indexranks, considering chemical thresholds of pollutants in sewage sludge from differents norms for agricultural use of sludge. All samples with SSHI above 2 (n = 15) had higher incidence of non-compliance then samples below 2 (n = 13). SSHI seems to be a good primary indicator of the hazard of sewage sludge samples, suggesting early approval or disapproval to agricultural use, also as a tool for monitoring and managing the quality of sludge, and for hazard communication
22

Leaching and recovery of molybdenum, nickel and cobalt from metals recycling plants mineral sludges / Lixiviation et récupération du molybdène, du nickel et du cobalt à partir des boues minérales générées par une usine de recyclage métallurgique

Vemic, Mirjana 26 October 2015 (has links)
Compte tenu de l'épuisement en cours des ressources naturelles qui ont lieu dans le monde entier, le prix élevé, la forte demande et la pénurie future des ressources minérales primaires pour Mo, Ni et Co, il est extrêmement important de mettre en œuvre le recyclage des métaux/récupération/réutilisation partir des demi-finis produits, sous-produits, des matériaux secondaires et des déchets, y compris les déchets dangereux (ce est à dire des catalyseurs usés, boues minérales). En outre, il est nécessaire d'utiliser des technologies plus efficaces pour récupérer des métaux à partir de déchets/ressources secondaires afin de minimiser les dépenses en capital, l'impact environnemental et de répondre à l'augmentation de la demande de métal. Parmi les différentes ressources secondaires, les catalyseurs usés et les boues minérales générés aux catalyseurs usés usines de recyclage pourrait être une très bonne ressource secondaire, car ils contiennent des concentrations élevées de métaux différents (en particulier Mo, Ni et Co). Par conséquent, ils doivent être considérés comme une ressource et non comme un déchet. Dans notre étude, nous traitons avec le catalyseur, l'oxyde métallique et le recyclage des piles minérales de la plante boues. Ce type de matériau contient de fortes concentrations de métaux différents. Cependant, au mieux de nos connaissances de spéciation, lixiviation et de récupération des propriétés de ce type de matériel n'ont pas été étudiés auparavant. Boues minérales a été minutieusement caractérisée où le pH, La perte au feu (LOI), Toxicité Caractéristique Lixiviation Procédure (TCLP), Diffraction des rayons X (XRD), Microscopie électronique à balayage (SEM) avec dispersion d'énergie des rayons X spectroscopie (EDS), Total Métal Contenu (TMC) et Extraction Séquentielle (SE) ont été effectuées. Sur la base des résultats de la caractérisation des boues minérales, le taux de lixiviation et les rendements de Mo, Ni et Co à partir de l'échantillon de boue minérale ont été quantifiés. Différents réactifs de lixiviation (autonome acides (nitrique, sulfurique et chlorhydrique) et les mélanges d'acides (eau régale (nitrique + chlorhydrique (1:3)), nitrique + sulfurique (1:1) et nitrique + sulfurique + chlorhydrique (2:1:1)) ont été étudiés à changer les paramètres de fonctionnement (solides ratio liquide, le temps de lixiviation et de la température), afin de comprendre les caractéristiques de lixiviation et sélectionnez le réactif de lixiviation approprié qui permet d'atteindre les plus hauts rendements de lixiviation de métal. Acide sulfurique (H2SO4) a été trouvé d'être le produit de lixiviation avec le potentiel de lixiviation des métaux les plus élevés. Les conditions de lixiviation optimales étaient une lixiviation en trois étapes successives, la température de 80°C, le temps de lixiviation 2 h, et S/L rapport 0.25 g L-1. Dans ces conditions, les rendements de lixiviation à partir de notre échantillon de boue minérale a atteint 85.5, 40.5 et 93.8% pour Mo, Ni et Co, respectivement / In view of the on-going depletion of the natural resources taking place worldwide, the high price, high demand and future shortage of the primary mineral resources for Mo, Ni and Co it is extremely important to implement metals recycling/recovery/reuse from semi-finished products, by-products, secondary materials and wastes, including hazardous waste (i.e. spent catalysts, mineral sludges). Furthermore, there is a need to utilize more efficient technologies to recover metals from wastes/secondary resources in order to minimize capital outlay, environmental impact and to respond to the metal increased demand. Among the different secondary resources, spent catalysts and mineral sludges generated at the spent catalysts recycling plants could be a very good secondary resource, as they contain high concentrations of different metals (especially Mo, Ni and Co). Therefore, they should be viewed as a resource, not as a waste. In our study we are dealing with the catalyst, metallic oxide and battery recycling plant mineral sludge. This type of material contains high concentrations of different metals. However, to the best of our knowledge, speciation, leaching and recovery of Mo, Ni and Co from this type of material were not investigated before. Mineral sludge was minutely characterized where pH, Loss On Ignition (LOI), Toxicity Characteristic Leaching Procedure (TCLP), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), Total Metal Content (TMC) and Sequential Extraction (SE) were performed. Based on the mineral sludge characterization results the leaching rate and yields of Mo, Ni and Co from mineral sludge sample were quantified. Different leaching reagents (stand-alone acids (nitric, sulfuric and hydrochloric) and acid mixtures (aqua regia (nitric + hydrochloric (1:3)), nitric + sulfuric (1:1) and nitric + sulfuric + hydrochloric (2:1:1)) were investigated at changing operational parameters (solid to liquid ratio, leaching time and temperature), in order to understand the leaching features and select the suitable leaching reagent which achieves the highest metal leaching yields. Sulfuric acid (H2SO4) was found to be the leachant with the highest metal leaching potential. The optimal leaching conditions were a three stage successive leaching, temperature 80°C, leaching time 2 h and S/L ratio 0.25 g L-1. Under these conditions, the leaching yields from our mineral sludge sample reached 85.5, 40.5 and 93.8% for Mo, Ni and Co, respectively
23

Valorisation des fines de lavage de granulats : application à la construction en terre crue / Development of re-use ways for washing aggregates sludges : application to unfired earth construction

Flament, Cédric 12 December 2013 (has links)
Les fines de lavage de carrières sont à l’heure actuelle peu valorisées. Pourtant, leurs caractéristiques physiques font de ces fines une matière première intéressante pour le domaine de la construction. L’objectif de cette thèse est de développer la formulation de produits préfabriqués non porteurs à base de fines de lavage, en considérant ces fines comme de la terre crue. Deux catégories de produits préfabriqués sont visées : un produit dit « lourd » (brique de terre comprimée) et un produit « léger » (carreau). Pour la valorisation en BTC, une étude de compacité par essai Proctor a permis de cibler la teneur en eau de fabrication et la masse volumique sèche à obtenir. Les performances mécaniques des briques ont été améliorées par surcompactage, renforcement granulaire et traitement au liant hydraulique. L’étude de formulation du carreau a associé les fines de lavage et la chènevotte. La consistance des mélanges à l’état frais a été étudiée avec le consistomètre VEBE. Les performances mécaniques en flexion et en compression des mélanges fibrés ont été mesurées. De la chaux et un superplastifiant ont été ajoutés dans la formulation pour satisfaire aux conditions de tenue mécanique. Les deux voies de valorisation ont été validées par mesures des performances physico-mécaniques sur produits fabriqués à l’échelle industrielle. La formulation optimale de BTC valorise près de 80% de fines de lavage et se classe dans la catégorie BTC 40 de la norme expérimentale XP13-901 (brique faiblement capillaire et résistante à la projection en eau). La formulation optimale de carreau se compose de 60% de fines de lavage, et répond aux exigences mécaniques des carreaux de plâtre. / Currently, few re-use ways are developed with clay fines from washing units in quarries. However, these clayey fines represent interesting materials for construction domain. This research work aims to develop non-load bearing precast products and to re-use these fines without thermal treatment as for unfired clay products. Two types of precast products are wished: a “heavy” product (compressed earth brick) and a “light” product (tile hemp-clay).For the CEB re-use way, the level of compaction has to be high. Proctor tests have been done to define the moisture content and dry density to obtain. Mechanical performances of bricks have been increased by overcompaction, granular reinforcement and lime treatment.For the tile re-use way, mixes with quarry fines and hemp have been studied. The behaviour of fresh material has been studied with VEBE consistometer. Flexural and compression strengths have been measured on hardened mixes. Lime and water-reducing agent have been necessary for a good mechanical behaviour.The two re-use ways have been validated by measuring mechanical and physical performances of products manufactured at industrial scale. The optimal mix for CEB includes almost 80% of quarry fines. The CEB is classed in BTC40 category according to experimental standard XP13-901 (brick with a low water absorption level and resistant to water spray). The optimal mix for tile includes 60% of quarry fines and satisfies mechanical requirements for gypsum blocks.
24

Abordagem sistêmica do sistema de tratamento de água de Registro, São Paulo, com ênfase na avaliação do impacto do descarte dos resíduos na bacia hidrográfica do Rio Ribeira de Iguape / Sistemic approach of water treatment plant of Registro, São Paulo, focusing the evaluation of the impact of the discharge of solid residues in Ribeira de Iguape River Basin

Reis, Edson Luís Tocaia dos 20 February 2006 (has links)
A crescente preocupação dos órgãos de vigilância ambiental e sanitária sobre a segurança e a qualidade dos recursos hídricos tem orientado o desenvolvimento de diversas pesquisas voltadas para uma revisão do padrão tecnológico atual, quanto à gestão de resíduos gerados em estações de tratamento de água. Neste trabalho, foram avaliadas as principais características dos resíduos gerados em um sistema de tratamento de água de ciclo completo na cidade de Registro (SP) e sua correlação com a qualidade do meio hídrico, pelo estudo dos efeitos físico-químicos de seu descarte na qualidade da água e do sedimento da Bacia Hidrográfica do rio Ribeira de Iguape. Um programa de monitoramento da microbacia foi estabelecido, verificando-se o atendimento dos elementos analisados ás exigências de legislações federais, como a Resolução CONAMA 357/2005 e a Portaria 518. Foram constatadas alterações na qualidade da água superficial do corpo d\'água receptor em períodos de até 4 horas, após o despejo, e para uma distância de até 50 m a jusante do descarte do lodo da ETA. A análise descritiva mostrou ser predominante a concentração de alguns metais durante o descarte, como o manganês. A análise dos organismos bentônicos apresentou uma indicação de que os grupos observados não foram diretamente afetados pelo despejo do lodo da ETA. O presente trabalho não detectou indícios de que a contaminação constatada no local de despejo atingisse o rio Ribeira de Iguape, porém, a presença de alumínio em amostras de sedimento próximo ao local de descarte mostrou que o descarte sistemático do lodo pode comprometer em longo prazo a qualidade da água do corpo d\'água receptor. / The growing concern of environmental and sanitary surveillance about the safety and the quality in the hydric resources, guides the development of many researches to a revision of the current technological pattern, related to the administration of residues generated in the water treatment plants. This work evaluated main characteristics of the residues generated in water treatment plant with complete cycle in the Registro town (SP) and the correlation with quality of the environment, by studying physical-chemical effects of its discharge in the quality of water and sediment of Ribeira de Iguape River Basin. A monitoring program was established, verifying the attendance of the elements analyzed to the demands of federal legislations, such as Resolução CONAMA 357/2005 and Portaria 518. Some alterations were verified in the quality of superficial water of the receiving watercourse, in periods up to 4 hours after the discharge and for a distance of 50 m to the place of the discard of sludge. The descriptive analysis showed to be predominant the concentration of some metals during the discharge, as manganese. The analysis of the benthonic organisms pointed out that the groups observed as typical of the area were not directly affected by sludge discharge. The present study did not detect indications that the contamination verified reached Ribeira de Iguape River. However, the systematic discharging of the sludge may commit at long date the water quality of the receiving watercourse.
25

Étude de la Nitrification partielle d'eaux ammoniacales dans un bioréacteur membranaire/Partial nitrification study on ammonia solutions using a Membrane Bioreactor

Kouakou, N'Guessan Edouard 16 February 2007 (has links)
Nitrogen is the major component of biosphere. Paradoxically, nitrogen pollution is the concern globally. Ammonia pollution is due to its unceasing rejection into nature such as groundwater, current water and the atmosphere. This phenomenon constitutes a threat for the humanity, land and aquatic flora, and consequently disturbs the balance of natural ecosystem. Recently, that situation has lead to develop various techniques and/or technologies for ammonia removal from municipal and industrial wastewaters. Particularly in the environmental biotechnology area, two main objectives were recently aimed in many research activities: the development of new configurations of competitive bioreactors and the monitoring of partial nitrification process, which are the fundamental basis of this thesis project. In this study, the partial ammonium oxidation process, also called nitrite route, was studied in a 60 litre jet-loop submerged membrane bioreactor pilot plant. The research was organized around six chapters. An exhaustive literature review of the state-of- art of the biological nitrification process and the membrane technologies was performed. The materials and measurement methods were presented. The colorimetric method, the chromatography analysis, the biomass estimation by the suspended solids (SS), the aggregates size measurement, the gas holdup, the gas-liquid mass transfer, the bubbles gas diameter determination, the medium rheology aspects, etc., and the complete equipment of the bioreactor were studied in detail. The plant automation functioning was also studied. Membrane module (Mitsubishi Sterapore-L) characterization was carried out and three characteristic parameters were estimated: the membrane intrinsic resistance Rm, the membrane permeability Lp and the membrane porosity εm. Estimations revealed good agreement between experimental results and theoretical methods based on the Darcys law and the Carman-Kozeny law applicable in microfiltration system. Hydrodynamics and aeration aspects were studied. The mixing in the jet-loop system was characterized by the mixing time (tmix) and the circulation time (tc), respectively. The results showed that the characteristic times (tmix and tc) decrease with an increase in input gas flowrate and the circulated liquid flowrate. A model correlation involving the air and the combined liquid effects was proposed to describe the circulation time evolution. The classical non-steady state clean water test was used to determine the gas-liquid mass transfer coefficient (kLa). It was found to be influenced by the combined action of air and recirculated-liquid flowrates and a correlation has been proposed to describe their influence. The interpretation of kLa results and the system mixing data showed that the developed reactor corresponds to a near perfect mixing tank. This criterion was satisfactorily verified by literature data. The gas holdup (εg) was directly measured by the volume expansion method. In the absence of liquid circulation, εg ranged between 1 and 4% for the investigated range of gas liquid superficial velocities. It was found to increase linearly with the air superficial velocity, which corresponds to the bubbly flow regime. However, in the presence of liquid flowrate, εg slightly increased (from 1 to 6%) with increase in the superficial liquid velocity. A model has been proposed to correlate εg and the air and the recirculated-liquid velocities. The average diameter of the bubbles gas (dB) in the system was also estimated by the Leibson theoretical model based on the Reynolds number at the orifice of the gas distributor. Finally, biological aspects were studied. Respirometry measurements were conducted to characterize the process medium. The mass transfer, the gas holdup and the medium viscosity were determined. The obtained data allowed estimating the α factor and the β factor, respectively. The interaction of the growth of microorganisms into the process and the membrane performance was also investigated and a correlation model was proposed to describe membrane fouling with time. The optimal conditions for ammonium partial oxidation were determined using process monitoring and simulation. Dissolved oxygen (DO), temperature (T) and hydraulic retention time (HRT) were selected to achieve a high nitrite accumulation in the system. The results obtained showed that the selected parameters should be fixed at DO ≈ 2 mgO2.l-1, HRT ≈ 6 7 h and T = 30°C, respectively. The partial nitrification was simulated by the use of the TwoPopNitrification model included into the BioWin 2.2 software. For these simulations, a sequencing ammonia oxidation assumption was adopted: the nitrozation followed by the nitration step, respectively. The corresponding kinetics and stoichiometric constants were estimated by combining literature data and experimental nitrification results. For these estimates, the ammonium oxidation was monitored on several process samples taken at different times. The estimates were also delivered by monitoring the ammonium oxidation on the process operated in the batch mode. The plotting of simulations and experimental results revealed good agreement. In order to investigate the process performance in terms of biological stability, a long time period (≈ 600 days) was simulated. The results showed that a high stable nitrite accumulation (> 95%) could be achieved when the above optimal conditions are imposed to the system. However, after a long time, the accumulated nitrite is converted into nitrate and then the system is disrupted. For the simulated experimental conditions, the process disruption period was located between 180 and 350 days. At this period, a corresponding theoretical purge flowrate was found to range between 0.15 10-3 m3.d-1 and 3.0 10-3 m3.d-1. Simulations also showed that increasing the purge flowrate decreases the sludge retention time and then favours nitrite accumulation into the process. That is an interesting strategy to increase the performance of the biological partial nitrification process.
26

Abordagem sistêmica do sistema de tratamento de água de Registro, São Paulo, com ênfase na avaliação do impacto do descarte dos resíduos na bacia hidrográfica do Rio Ribeira de Iguape / Sistemic approach of water treatment plant of Registro, São Paulo, focusing the evaluation of the impact of the discharge of solid residues in Ribeira de Iguape River Basin

Edson Luís Tocaia dos Reis 20 February 2006 (has links)
A crescente preocupação dos órgãos de vigilância ambiental e sanitária sobre a segurança e a qualidade dos recursos hídricos tem orientado o desenvolvimento de diversas pesquisas voltadas para uma revisão do padrão tecnológico atual, quanto à gestão de resíduos gerados em estações de tratamento de água. Neste trabalho, foram avaliadas as principais características dos resíduos gerados em um sistema de tratamento de água de ciclo completo na cidade de Registro (SP) e sua correlação com a qualidade do meio hídrico, pelo estudo dos efeitos físico-químicos de seu descarte na qualidade da água e do sedimento da Bacia Hidrográfica do rio Ribeira de Iguape. Um programa de monitoramento da microbacia foi estabelecido, verificando-se o atendimento dos elementos analisados ás exigências de legislações federais, como a Resolução CONAMA 357/2005 e a Portaria 518. Foram constatadas alterações na qualidade da água superficial do corpo d\'água receptor em períodos de até 4 horas, após o despejo, e para uma distância de até 50 m a jusante do descarte do lodo da ETA. A análise descritiva mostrou ser predominante a concentração de alguns metais durante o descarte, como o manganês. A análise dos organismos bentônicos apresentou uma indicação de que os grupos observados não foram diretamente afetados pelo despejo do lodo da ETA. O presente trabalho não detectou indícios de que a contaminação constatada no local de despejo atingisse o rio Ribeira de Iguape, porém, a presença de alumínio em amostras de sedimento próximo ao local de descarte mostrou que o descarte sistemático do lodo pode comprometer em longo prazo a qualidade da água do corpo d\'água receptor. / The growing concern of environmental and sanitary surveillance about the safety and the quality in the hydric resources, guides the development of many researches to a revision of the current technological pattern, related to the administration of residues generated in the water treatment plants. This work evaluated main characteristics of the residues generated in water treatment plant with complete cycle in the Registro town (SP) and the correlation with quality of the environment, by studying physical-chemical effects of its discharge in the quality of water and sediment of Ribeira de Iguape River Basin. A monitoring program was established, verifying the attendance of the elements analyzed to the demands of federal legislations, such as Resolução CONAMA 357/2005 and Portaria 518. Some alterations were verified in the quality of superficial water of the receiving watercourse, in periods up to 4 hours after the discharge and for a distance of 50 m to the place of the discard of sludge. The descriptive analysis showed to be predominant the concentration of some metals during the discharge, as manganese. The analysis of the benthonic organisms pointed out that the groups observed as typical of the area were not directly affected by sludge discharge. The present study did not detect indications that the contamination verified reached Ribeira de Iguape River. However, the systematic discharging of the sludge may commit at long date the water quality of the receiving watercourse.
27

Termické zpracování kalů z ČOV / Sewage sludge incineration

Švehlová, Tereza January 2014 (has links)
The master´s thesis deals with the problem of sewage sludge from wastewater treatment plants and their subsequent incineration. Main aim is compare some possibilities of the energy use of mechanically dewatered sewage sludge and sewage sludge with previous anaerobic pre-treatment for various levels of drying sludge.

Page generated in 0.0325 seconds