• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 25
  • 19
  • 3
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 73
  • 73
  • 18
  • 16
  • 15
  • 13
  • 12
  • 11
  • 10
  • 10
  • 9
  • 9
  • 8
  • 7
  • 6
  • 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.
31

Drivers and Barriers to Circular Water Economy Implementation in Ohio

Hull, MacKenzie S. January 2022 (has links)
No description available.
32

Water crisis in cities : an investigation into the contribution of water demand management towards mitigating the scarcity of potable water in the city of Bulawayo

Khumalo, Sihlanganiso 11 1900 (has links)
The study investigates the contribution of WDM towards mitigating scarcity of potable water in cities with particular reference to Bulawayo.WDM origins and its successes are traced. The study classifies scarcity representations into four categories and reveals that the scarcity in Bulawayo satisfies all the four representations hence calls it total scarcity. The research employed document study, questionnaires, interviews and a focus group to collect data. Document study revealed that water restrictions successfully mitigate the scarcity in Bulawayo. Field work partially confirmed the usefulness of WDM in the life of the city and revealed the need to synchronize the conceptualizations of WDM among different stakeholders in order for the paradigm to do even more in terms of mitigating scarcity. The results were interpreted in terms of TPB. The key recommendation of the study is that the city invests in water use behaviour change in order to realise huge water savings. / Development Studies / M.A. (Development Studies)
33

Water crisis in cities : an investigation into the contribution of water demand management towards mitigating the scarcity of potable water in the city of Bulawayo

Khumalo, Sihlanganiso 11 1900 (has links)
The study investigates the contribution of WDM towards mitigating scarcity of potable water in cities with particular reference to Bulawayo.WDM origins and its successes are traced. The study classifies scarcity representations into four categories and reveals that the scarcity in Bulawayo satisfies all the four representations hence calls it total scarcity. The research employed document study, questionnaires, interviews and a focus group to collect data. Document study revealed that water restrictions successfully mitigate the scarcity in Bulawayo. Field work partially confirmed the usefulness of WDM in the life of the city and revealed the need to synchronize the conceptualizations of WDM among different stakeholders in order for the paradigm to do even more in terms of mitigating scarcity. The results were interpreted in terms of TPB. The key recommendation of the study is that the city invests in water use behaviour change in order to realise huge water savings. / Development Studies / M.A. (Development Studies)
34

Management of the re-routing of water destined for domestic use by the city of Potchefstroom / Elrista Annandale

Annandale, Elrista January 2014 (has links)
Water is an essential element for life and crucial to survival. South Africa is a semi-arid country and therefore water should be protected and managed effectively by all residents of the country. In the 1830s the Mooi River was the key reason for the Voortrekkers to establish Potchefstroom at a locality adjacent to this river. The Voortrekkers noticed the dolomitic outcroppings in the vicinity, but still opted to reside next to the river for it provided easily accessible water and fertile soil. Since the 1830s water legislation regulating the management and use of the water in the Mooi River has been amended innumerable times to bring us to the current situation of Potchefstroom’s water (mis)management by the role-players and stakeholders of the water source. As a resident of Potchefstroom, the researcher has a keen interest in the origin of the city’s water sources, the re-routing of the water from the origin to the water purification unit via the open-on-top cement canal system, and the overall management of these canals and their servitudes. In order to conduct a research study on the Mooi River’s water re-routing canals and servitudes, the following research methods were applied: The researcher performed a comprehensive literature review, conducted fieldwork, held interviews with landowners and experts in the geographical area of the Mooi River Valley, and performed statistical analyses as well as content analyses of the findings. Some of the most alarming findings include the lack of co-operative governance between water users and – authorities, and the current public management and disaster risk management challenges in the re-routing of water from Klerkskraal Dam down to the water purification plant of Potchefstroom. It is recommended that the major stakeholders of the Mooi River Valley, e.g. the disaster management centre in Potchefstroom, the Department of Water and Sanitation’s (DWS) regional offices in Potchefstroom, as well as the Tlokwe Local Municipality need to join forces for a combined effort to accomplish the overarching research objective of achieving improved cooperative municipal governance and Integrated Water Resources Management (IWRM) to eventually ensure the safe and effective re-routing of water from the Klerkskraal Dam to the Potchefstroom water purification plant. Note: Since July 2014 the Department of Water Affairs (DWA) has changed to the Department of Water and Sanitation (DWS). / MA (Public Management and Governance), North-West University, Potchefstroom Campus, 2015
35

Management of the re-routing of water destined for domestic use by the city of Potchefstroom / Elrista Annandale

Annandale, Elrista January 2014 (has links)
Water is an essential element for life and crucial to survival. South Africa is a semi-arid country and therefore water should be protected and managed effectively by all residents of the country. In the 1830s the Mooi River was the key reason for the Voortrekkers to establish Potchefstroom at a locality adjacent to this river. The Voortrekkers noticed the dolomitic outcroppings in the vicinity, but still opted to reside next to the river for it provided easily accessible water and fertile soil. Since the 1830s water legislation regulating the management and use of the water in the Mooi River has been amended innumerable times to bring us to the current situation of Potchefstroom’s water (mis)management by the role-players and stakeholders of the water source. As a resident of Potchefstroom, the researcher has a keen interest in the origin of the city’s water sources, the re-routing of the water from the origin to the water purification unit via the open-on-top cement canal system, and the overall management of these canals and their servitudes. In order to conduct a research study on the Mooi River’s water re-routing canals and servitudes, the following research methods were applied: The researcher performed a comprehensive literature review, conducted fieldwork, held interviews with landowners and experts in the geographical area of the Mooi River Valley, and performed statistical analyses as well as content analyses of the findings. Some of the most alarming findings include the lack of co-operative governance between water users and – authorities, and the current public management and disaster risk management challenges in the re-routing of water from Klerkskraal Dam down to the water purification plant of Potchefstroom. It is recommended that the major stakeholders of the Mooi River Valley, e.g. the disaster management centre in Potchefstroom, the Department of Water and Sanitation’s (DWS) regional offices in Potchefstroom, as well as the Tlokwe Local Municipality need to join forces for a combined effort to accomplish the overarching research objective of achieving improved cooperative municipal governance and Integrated Water Resources Management (IWRM) to eventually ensure the safe and effective re-routing of water from the Klerkskraal Dam to the Potchefstroom water purification plant. Note: Since July 2014 the Department of Water Affairs (DWA) has changed to the Department of Water and Sanitation (DWS). / MA (Public Management and Governance), North-West University, Potchefstroom Campus, 2015
36

Impact potentiel de l’utilisation de l’eau de pluie dans le bâtiment sur les consommations d’eau potable à l’échelle urbaine : le cas de l’agglomération parisienne / Potential impact of the use of rainwater within buildings on the consumption of drinking water at a city scale : case of Paris conurbation

Belmeziti, Ali 06 July 2012 (has links)
Ce travail de recherche vise à appréhender les effets engendrés à terme sur la gestion urbaine de l'eau par le développement progressif de la pratique de récupération et d'utilisation de l'eau de pluie (RUEP), et plus particulièrement sur l'alimentation en eau potable. Il est réalisé de manière prospective à l'échelle de l'agglomération parisienne. Plus largement, cette recherche constitue une contribution au débat ouvert depuis quelques années relatif à la remise en question progressive du modèle centralisé de gestion de l'eau en milieu urbain. Après une description de la pratique urbaine de REUP, ce travail établit un état de l'art des outils et des méthodes scientifiques s'y rapportant, et suggère de se focaliser sur le développement d'une approche de changement d'échelles. L'objectif est de produire, à une échelle urbaine, une estimation significative des économies d'eau potable réalisables en substituant à celle-ci de l'eau de pluie récupérée pour des usages ne requérant pas une qualité d'eau alimentaire. Pour ce faire, nous proposons une approche basée sur l'évaluation séquentielle à l'aide d'une échelle intermédiaire (la commune), d'une logique de regroupement de bâtiments aux caractéristiques comparables au regard de la RUEP et de quatre principes (distinction, agrégation, majoration, hiérarchisation).Sur l'agglomération de Paris, la méthodologie mise en œuvre montre que l'eau de pluie récupérée est susceptible de représenter un potentiel équivalent à 65% des besoins en eau non potable et à 11% du volume d'eau potable distribué. Le travail met également en évidence que le secteur résidentiel constitue le gisement principal de ce potentiel, car il détient 2/3 du potentiel global de l'agglomération. Une première analyse du système d'acteurs impliqués dans la RUEP en milieu urbain complète ce travail. Cette analyse permet de dégager un sous ensemble particulier d'acteurs qui ont la capacité d'effectuer une action « levier » sur la diffusion de cette pratique sur une échelle urbaine, soit directement en raison de leur capacité d'action collective (un ensemble de bâtiments par exemple), soit indirectement au travers de leur capacité d'influencer sur les propriétaires des bâtiments (mécanismes d'incitation notamment).Au final, ce travail permet de situer la RUEP en milieu urbain au sein du débat général portant sur les mutations que connaît la ville d'aujourd'hui / This research aims at assessing the effects generated, on management of urban water in the long term, by progressive development of rainwater harvesting (RWH), and more particularly on the drinking water supply. It is carried out in a prospective way on the scale of Paris and its suburbs. On the whole, this research contributes to a controversy about the validity of a centralized model of management of water in an urban environment. After a description of the RWH in urban areas, this report presents state of the art tools and scientific methods, and focuses on the development of a scaling approach. The objective is to produce, a significant assessment of potential potable water savings (PPWS), on an urban scale by substituting part of it by rainwater recovered for uses which do not require such quality. With this aim, we propose an approach based on sequential evaluation using an intermediate scale (the municipality), on merging of buildings with similar characteristics related to RWH and four methodological principles (modeling, aggregation, increase, Ranking strategy)Applied to the Paris agglomeration, the implemented methodology shows that the recovered rainwater volume is likely to represent a potential equivalent of 65% of the demands for non-drinking water and of 11% of the drinking water distributed. This research also highlights that the residential sector constitutes the major contribution of this potential, because it holds 2/3 of the total potential to the Paris agglomeration. The first analysis of the system of actors implied in the RWH in urban environment has also been developed. This analysis makes it possible to identify a specific subset of actors who have the capacity to carry out an “lever” action in generalizing this practice on an urban scale, either directly because of their capacity of leading a collective action (for a set of buildings for example), or indirectly through their capacity to act on the owners of the buildings (by incentive mechanisms in particular).Finally, this work positions RWH in on urban environment within the general debate related to the evolution of present cities
37

Modelo para tomada de decisão entre a produção de água não potável em edifícios e a produção de água potável pelo Sistema Produtor São Lourenço. / Decision making model between the non-potable water production in buildings and the drinking water production by the São Lourenço Producer System.

Patucci, Renato Augusto 17 May 2019 (has links)
O adensamento populacional que as metrópoles vivenciam contribui para reduzir a disponibilidade específica de água, medida em m³/hab.ano. Adicionalmente a este evento, quando o crescimento urbano ocorre de forma não planejada, isso impacta também a qualidade dos mananciais. Esses dois efeitos ocorrem de forma combinada, sobretudo na Região Metropolitana de São Paulo (RMSP). Como consequência observam-se opções de ampliação da capacidade de produção de água potável sucessivamente mais custosas, seja por processos mais caros para o tratamento de um manancial mais poluído, próximo ao centro consumidor, seja pela maior distância de um manancial não poluído, e maiores custos com obras, como ocorre atualmente na implantação do Sistema Produtor São Lourenço (SPSL). Esse processo de encarecimento das opções para ampliação do sistema centralizado de produção de água potável persistirá na RMSP, conforme a população continue a aumentar nas próximas décadas. Existem fontes alternativas com disponibilidade satisfatória, como a água residuária, que quando adequadamente tratadas, podem ser direcionadas para usos que não demandam água potável. Essa possibilidade tem sido aproveitada de forma crescente pelo mercado imobiliário em edifícios, através da instalação de sistemas prediais de água não potável (SPANP), e há diferentes tecnologias disponíveis se consolidando com custos em tendência de queda. Nesse contexto, o objetivo da pesquisa é formular um modelo matemático de tomada de decisão para verificar se a utilização de SPANP são viáveis em relação à implantação do SPSL. Para o desenvolvimento da pesquisa, realizou-se revisão bibliográfica para avaliar as experiências de implantação de SPANP com fonte de águas cinzas em diferentes localidades, bem como para estabelecer a comparação de produção de água potável em macroescala em relação à produção de água não potável em microescala. Foram coletados dados quanto aos custos de construção, operação e manutenção de um SPANP em operação em um edifício na RMSP, e o mesmo para o SPSL. Por meio dos princípios da Programação Inteira, foi formulado um modelo para a indicação de qual opção de sistema apresenta o menor custo total acumulado durante os 20 primeiros anos de operação. Foram simulados cinco cenários com a alteração das principais variáveis que influenciam o comportamento da viabilidade das opções, sendo que as simulações foram realizadas com o uso do software LINDOTM. Em quatro dos cinco cenários simulados, o SPSL foi a opção de menor custo acumulado no 20o ano de operação, indicando a maior probabilidade do mesmo ser a opção de implantação mais econômica no presente. No entanto, devido à tendência de encarecimento das alternativas de ampliação do sistema centralizado de produção de água potável e de redução de custos dos SPANP, essa conclusão não pode ser adotada automaticamente quanto ao próximo sistema centralizado de água potável planejado para ser implantado. / The population agglomeration phenomenon that the metropolises pass through, reduces the water availability measured by the indicator m³/hab.year. Additionally, when urban growth happen in an unplanned way, it also impacts the quality of the water sources. These two effects occur in a combined way, especially in the São Paulo Metropolitan Region (SPMR). As a consequence, the options for expanding the production capacity of drinking water are successively more costly, either by more expensive processes for the treatment of a more polluted source, near the consumer center, or by the larger distance of an unpolluted source, and higer costs with construction, as it is currently happening in the implementation of the São Lourenço Producer System (SLPS). The process that is turning expensive the options for expanding the centralized drinking water system will persist in the SPMR as the population continues to increase in the coming decades. There are alternative sources with satisfactory availability, such as wastewater, which when properly treated, can be directed to uses that do not require potable water. This possibility has been used more and more by the real estate market in buildings, through the installation of non-potable water systems (NPWS), and there are different technologies available in consolidation with falling costs. Thus, the objective of the research is to formulate a mathematical decision making model to verify if the use of NPWS are viable in relation to the implementation of the SLPS. For the development of the research, a bibliographical review was carried out to evaluate the experiences of implementation of NPWS with source of gray water in different localities, as well as to establish the comparison of production of drinking water in macro scale in relation to the production of non-potable water in micro scale. Data were collected on the costs of construction, operation and maintenance of NPWS in a building in the SPMR, and the same for SLPS. Through the principles of Integer Programming, a model was formulated to indicate which system option has the lowest accumulated total cost during the first 20 years of operation. Five scenarios were simulated with the change of the main variables that influence the viability behavior of the options, the simulations were performed using LINDOTM software. In four of the five simulated scenarios, SLPS was the lowest accumulated cost option in the 20th year of operation, indicating that it is more likely to be the most economical deployment option in the present. However, due to the rising cost of alternatives for the expansion of the centralized drinking water production system and the cost reduction of NPWSs, this conclusion cannot be automatically adopted for the next centralized drinking water system planned to be implemented.
38

Sistema automatizado baseado em língua eletrônica para monitoração de água para abastecimento urbano. / Automated system based on electronic tongue system for urban water supply monitoring.

Guilherme de Souza Braga 12 December 2011 (has links)
A presente tese trata do desenvolvimento de uma língua eletrônica (LE) e da avaliação de seu uso na detecção de 2-metilisoborneol (MIB), geosmina (GEO) e isoborneol (ISO) em amostras de água. A água abastecida à região metropolitana de São Paulo provém de mananciais, os quais estão sujeitos à ploriferação de algas (eutrofização). Muitas delas podem ser tóxicas e ainda produzir compostos, como MIB e GEO, substâncias reconhecidas por provocar gosto e odor desagradáveis na água que consumimos. De fato, a presença de MIB e GEO na água é uma das maiores fontes de reclamação por parte dos consumidores junto à companhia de saneamento e abastecimento de São Paulo (SABESP). Apesar disso, ainda não existem tecnologias que possam ser aplicadas para a detecção in locu dessas substâncias. A LE usada nesta tese foi baseada em um arranjo de sensores químicos não-específicos, formados por microeletrodos interdigitados de ouro recobertos com filmes poliméricos nanoestruturados depositados pela técnica de automontagem e interrogados sob regime de corrente alternada. A calibração da LE foi realizada com soluções de concentração determinada de GEO, MIB e ISO preparadas em água destilada, mineral e de torneira. Foram avaliadas tanto soluções individuais contendo um único contaminante, quanto misturas contendo MIB e GEO. A resposta elétrica dos sensores (medidas de capacitância), foram interpretadas por análise das componentes principais (PCA) e por lógica Fuzzy, com as quais a LE consegue discriminar as diversas amostras com relativa facilidade e confiabilidade. Dentre as principais observações dessa investigação, notou-se que a LE desenvolvida consegue detectar MIB e GEO em amostras de água reais em concentrações tão baixas quanto 20 ng L-1. Os gráficos de PCA mostram a separação das amostras em clusters relativamente pequenos, bem separados e sem sobreposição. A LE é capaz de identificar de forma direta, a partir de variações na primeira componente principal, variações na razão molar nGEO/nMIB em misturas de MIB e GEO. Em um caso mais próximo da realidade, a LE consegue discriminar com relativa facilidade, amostras de água fornecidas pela SABESP, coletadas do sistema Guarapiranga antes e após a estação de tratamento. As taxas de acerto da LE usando os controladores Fuzzy desenvolvidos são próximas de 100% para a maioria das amostras. A menor taxa de acerto (93,33%) ocorreu com as amostras preparadas em água de torneira. Adicionalmente, nenhuma amostra de água pura foi classificada como contendo algum contaminante, ou seja, não houve falsos positivos. Conclui-se, portanto que a LE desenvolvida, tanto em termos de sensores quanto de análise de dados, apresenta potencial para monitoramento de MIB e GEO nos reservatórios de água, fornecendo em tempo real e in loco informações sobre a qualidade da água provinda da estação de tratamento. A tese também apresenta alguns resultados da preparação de filmes poliméricos com impressão molecular para aplicação em sensores específicos, obtidos durante o estágio na Universidade Autônoma de Barcelona. / Water from São Paulo metropolitan area comes from water reservoirs, which are prone to algae bloom (eutrophication). These algae can be toxic and produce compounds, such as geosmin (GEO) and 2-methylisoborneol (MIB) that give unpleasant taste and odour to the water supplied to consumers. In fact, their presence in water is one of the major complains of consumers to São Paulo\'s water company (SABESP). Despite that, technologies that can be applied for monitoring these substances in real time and in locu are still not available. In this sense, the present thesis work has focused on the development of an electronic tongue system (ET) and evaluate its performance on detecting MIB, GEO and isoborneol (ISO) in water samples. The ET is based on an array of non-specific chemical sensors, which are made of gold interdigitated microelectrodes covered with nanostructured polymeric films deposited via the layer-by-layer technique and interrogated in alternate current regime. The ET calibration was conducted by analyzing distilled, mineral and tap water samples tainted with known concentrations of MIB, GEO and ISO. The samples were solutions with a single tainting compound and solutions containing MIB and GEO mixed together. The sensors\' electrical response (capacitance measurements) was interpreted by principal component analysis (PCA) and Fuzzy logic. Among the main features of this work, the present ET presents a detection limit of about 20 ng L-1 for both tainting compounds. The ET can also discriminate with great easiness and confiability individual and mixture samples. PCA plots show that samples are grouped into relatively small and well-separeted clusters (no overlapping). The ET is also capable of detect, based on changes on the first principal component, changes in the nGEO/nMIB molar ratio of mixed samples. Also, the ET can discriminate with great easiness, water samples supplied by SABESP, collected at Guarapiranga\'s reservoir, before and after the water treatment plant. The influence of the water type on the sensors\' response has little significance when the Fuzzy controller is employed. The ET with the Fuzzy controller presents an excellent performance with very low error rates: 0.25% (distilled water), 5% (mineral water) and 6.66% (tap water). Besides that, Fuzzy logic results can be displayed in simpler plots which ensures easier readings of hit and error rates of the ET. Also, the numeric values (compound concentration) can be replaced by linguistic variables such as proper and improper. Finally, it can be concluded that the ET developed herein, when considering sensor and data analysis, shows a great potential for monitoring MIB and GEO in water reservoirs, providing in real time and in locu information about water quality in treatment stations. This thesis also presents the study on the assembly of molecularly imprinted polymeric films to be used in specific chemical sensors, carried out during the internship at the Universidade Autonoma de Barcelona.
39

O direito humano à água potável e a resolução de conflitos ambientais pelo Ministério Público

Barcellos, Rodrigo Alves 19 December 2017 (has links)
O estudo busca identificar a realidade dos litígios ambientais que envolvem o direito humano à água, apresentando mecanismos autocompositivos de resolução da conflituosidade, por meio da atuação do Ministério Público. Como recorte específico, a dissertação aborda a situação alarmante dos corpos hídricos da bacia hidrográfica do Rio Formoso, na região sudoeste do Estado do Tocantins. A base teórica do estudo focou nas contribuições de autores e pesquisadores nas áreas do direito ambiental, geografia, ecologia e agronomia. A base metodológica ateve-se ao levantamento bibliográfico, estatístico, análise documental e processual. Reconheceu-se que acesso à justiça não é acesso ao Poder Judiciário, mas à solução do litígio com agilidade, eficiência, adequação, profissionalismo e compromisso social. O direito à água potável envolve questão de justiça ambiental e o órgão constitucionalmente incumbido da defesa do regime democrático deve oferecer alternativas para assegurar a todos uma vida com dignidade, valor supremo de uma sociedade comprometida com a solução pacífica dos conflitos, conforme preâmbulo da Constituição. Após o estudo das bases principiológicas do Direito Ambiental e da gestão dos recursos hídricos, palmilharam-se os caminhos da excessiva litigiosidade que sobrecarrega os tribunais brasileiros para identificar a necessidade de ampliar conhecimentos acerca da moderna teoria do conflito como forma de inspirar a atuação dos integrantes do Ministério Público a adotar, preferencialmente, métodos autocompositivos de resolução de conflitos. / The study seeks to identify the reality of environmental disputes involving the human right to water, by presenting mechanisms for solving conflicts, through the work of the Public Prosecution Service. As a specific clipping, the dissertation addresses the alarming situation of the water bodies of the Rio Formoso hydrological basin, in the southwest region of the state of Tocantins. The theoretical background of the study was based on the contributions of authors and researchers in the areas of environmental law, geography, ecology and agronomy. The methodological basis was based on bibliographical, statistical, documental and procedural analysis. It was recognized that access to justice is not access to the Judiciary, but to the solution of the litigation with agility, efficiency, adequacy, professionalism and social commitment. The right to clean water involves a question of environmental justice and the body constitutionally mandated to defend the democratic regime must offer alternatives to ensure a dignified life for all, a supreme value of a society committed to the peaceful resolution of conflicts, according to the preamble of the Constitution. After studying the principles of Environmental Law and the management of water resources, the paths of excessive litigiousness that overload the Brazilian courts to identify the need to expand knowledge about the modern theory of conflict as a way of inspiring the action of the members of the Public Prosecutor's Office to adopt, preferably, self-composed methods of conflict resolution.
40

Sistema automatizado baseado em língua eletrônica para monitoração de água para abastecimento urbano. / Automated system based on electronic tongue system for urban water supply monitoring.

Braga, Guilherme de Souza 12 December 2011 (has links)
A presente tese trata do desenvolvimento de uma língua eletrônica (LE) e da avaliação de seu uso na detecção de 2-metilisoborneol (MIB), geosmina (GEO) e isoborneol (ISO) em amostras de água. A água abastecida à região metropolitana de São Paulo provém de mananciais, os quais estão sujeitos à ploriferação de algas (eutrofização). Muitas delas podem ser tóxicas e ainda produzir compostos, como MIB e GEO, substâncias reconhecidas por provocar gosto e odor desagradáveis na água que consumimos. De fato, a presença de MIB e GEO na água é uma das maiores fontes de reclamação por parte dos consumidores junto à companhia de saneamento e abastecimento de São Paulo (SABESP). Apesar disso, ainda não existem tecnologias que possam ser aplicadas para a detecção in locu dessas substâncias. A LE usada nesta tese foi baseada em um arranjo de sensores químicos não-específicos, formados por microeletrodos interdigitados de ouro recobertos com filmes poliméricos nanoestruturados depositados pela técnica de automontagem e interrogados sob regime de corrente alternada. A calibração da LE foi realizada com soluções de concentração determinada de GEO, MIB e ISO preparadas em água destilada, mineral e de torneira. Foram avaliadas tanto soluções individuais contendo um único contaminante, quanto misturas contendo MIB e GEO. A resposta elétrica dos sensores (medidas de capacitância), foram interpretadas por análise das componentes principais (PCA) e por lógica Fuzzy, com as quais a LE consegue discriminar as diversas amostras com relativa facilidade e confiabilidade. Dentre as principais observações dessa investigação, notou-se que a LE desenvolvida consegue detectar MIB e GEO em amostras de água reais em concentrações tão baixas quanto 20 ng L-1. Os gráficos de PCA mostram a separação das amostras em clusters relativamente pequenos, bem separados e sem sobreposição. A LE é capaz de identificar de forma direta, a partir de variações na primeira componente principal, variações na razão molar nGEO/nMIB em misturas de MIB e GEO. Em um caso mais próximo da realidade, a LE consegue discriminar com relativa facilidade, amostras de água fornecidas pela SABESP, coletadas do sistema Guarapiranga antes e após a estação de tratamento. As taxas de acerto da LE usando os controladores Fuzzy desenvolvidos são próximas de 100% para a maioria das amostras. A menor taxa de acerto (93,33%) ocorreu com as amostras preparadas em água de torneira. Adicionalmente, nenhuma amostra de água pura foi classificada como contendo algum contaminante, ou seja, não houve falsos positivos. Conclui-se, portanto que a LE desenvolvida, tanto em termos de sensores quanto de análise de dados, apresenta potencial para monitoramento de MIB e GEO nos reservatórios de água, fornecendo em tempo real e in loco informações sobre a qualidade da água provinda da estação de tratamento. A tese também apresenta alguns resultados da preparação de filmes poliméricos com impressão molecular para aplicação em sensores específicos, obtidos durante o estágio na Universidade Autônoma de Barcelona. / Water from São Paulo metropolitan area comes from water reservoirs, which are prone to algae bloom (eutrophication). These algae can be toxic and produce compounds, such as geosmin (GEO) and 2-methylisoborneol (MIB) that give unpleasant taste and odour to the water supplied to consumers. In fact, their presence in water is one of the major complains of consumers to São Paulo\'s water company (SABESP). Despite that, technologies that can be applied for monitoring these substances in real time and in locu are still not available. In this sense, the present thesis work has focused on the development of an electronic tongue system (ET) and evaluate its performance on detecting MIB, GEO and isoborneol (ISO) in water samples. The ET is based on an array of non-specific chemical sensors, which are made of gold interdigitated microelectrodes covered with nanostructured polymeric films deposited via the layer-by-layer technique and interrogated in alternate current regime. The ET calibration was conducted by analyzing distilled, mineral and tap water samples tainted with known concentrations of MIB, GEO and ISO. The samples were solutions with a single tainting compound and solutions containing MIB and GEO mixed together. The sensors\' electrical response (capacitance measurements) was interpreted by principal component analysis (PCA) and Fuzzy logic. Among the main features of this work, the present ET presents a detection limit of about 20 ng L-1 for both tainting compounds. The ET can also discriminate with great easiness and confiability individual and mixture samples. PCA plots show that samples are grouped into relatively small and well-separeted clusters (no overlapping). The ET is also capable of detect, based on changes on the first principal component, changes in the nGEO/nMIB molar ratio of mixed samples. Also, the ET can discriminate with great easiness, water samples supplied by SABESP, collected at Guarapiranga\'s reservoir, before and after the water treatment plant. The influence of the water type on the sensors\' response has little significance when the Fuzzy controller is employed. The ET with the Fuzzy controller presents an excellent performance with very low error rates: 0.25% (distilled water), 5% (mineral water) and 6.66% (tap water). Besides that, Fuzzy logic results can be displayed in simpler plots which ensures easier readings of hit and error rates of the ET. Also, the numeric values (compound concentration) can be replaced by linguistic variables such as proper and improper. Finally, it can be concluded that the ET developed herein, when considering sensor and data analysis, shows a great potential for monitoring MIB and GEO in water reservoirs, providing in real time and in locu information about water quality in treatment stations. This thesis also presents the study on the assembly of molecularly imprinted polymeric films to be used in specific chemical sensors, carried out during the internship at the Universidade Autonoma de Barcelona.

Page generated in 0.0554 seconds