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  • 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.
41

Sustainability of Community-Managed Rural Water Supply Systems in Amazonas, Peru: Assessing Monitoring Tools and External Support Provision

Mangum, Jacob E. 26 October 2017 (has links)
Globally, there is still a large number of people without access to safe drinking water; a known health risk. In rural areas of countries like Peru, when potable water systems are built the responsibility for maintaining these systems is given to volunteer water committees. Despite its prevalence as a management model, there is a consensus that community management alone cannot ensure sustainable water service. Therefore, the overall goal of this research is to assess the sustainability of community-managed water systems in rural areas of the department of Amazonas, Peru. Specifically, this research examines two mechanisms that have been shown to improve the sustainability of rural water systems: 1) monitoring for asset management and service delivery, and 2) provision of long-term external support. In Amazonas, three sustainability assessment tools have been used recently to monitor the service level and management of water systems. These assessment tools are: the Rural Water and Sanitation Information System (SIASAR, in Spanish), Tracers in Rural Water and Sanitation (Trazadores, in Spanish), and the Diagnostic Survey for Water Supply and Sanitation (Diagnostico, in Spanish). The three tools were assessed using a question mapping technique as well as a sustainability assessment tool evaluation matrix. This analysis identified the SIASAR assessment tool to be the most appropriate for ensuring sustainability of rural water supply systems. This research also used the data collected with the SIASAR and Trazadores assessment tools to assess the state of community-managed rural water systems in Amazonas. The analysis showed that 81% of systems in the SIASAR analysis and 58% of systems in the Trazadores analysis have deficiencies that are beyond the ability of the water committee to overcome. In recent years, the Peruvian government has prioritized the creation of an office in each district dedicated to providing external technical support to local water committees. This office, called the Área Técnica Municipal de Agua y Saneamiento (ATM), is charged with formalizing and training water committees which are given the name, Juntas Administradoras de los Servicios de Saneamiento (JASS). In order to examine the provision of long-term external support provided by the ATM to the JASS, field research was conducted in six districts in Amazonas. Valuable anecdotal evidence was provided by the field research that helped to form recommendations for strengthening the capacity of the ATM office at the local municipal level. The results of this research demonstrate that currently a large number of community-managed rural water systems in Amazonas are not sustainable but that the prioritization of monitoring and external support is an encouraging sign. If these mechanisms continue to be prioritized then it is highly likely that water systems throughout Amazonas and Peru will become more sustainable, bringing benefits to millions of Peruvians in rural areas.
42

Creating a New Model to Predict Cooling Tower Performance and Determining Energy Saving Opportunities through Economizer Operation

Yedatore Venkatesh, Pranav 17 July 2015 (has links)
Cooling towers form an important part of chilled water systems and perform the function of rejecting the heat to the atmosphere. These systems are often not operated optimally, and cooling towers being an integral part of the system present a significant area to study and determine possible energy saving measures. Operation of cooling towers in economizer mode in winter and variable frequency drives (VFDs) on cooling tower fans are measures that can provide considerable energy savings. The chilled water system analysis tool (CWSAT) software is developed as a primary screening tool for energy evaluation for chilled water systems and quantifies the energy usage of the various components and typical measures that can be applied to these systems to conserve energy, all while requiring minimum number of inputs to analyze component-wise energy consumption and incurred overall cost. A careful investigation of the current model in CWSAT indicates that the prediction capability of the model at lower wet bulb temperatures and at low fan power is not very accurate. A new model for accurate tower performance prediction is imperative, since economizer operation occurs at low temperatures and most cooling towers come equipped with VFDs. In this thesis, a new model to predict cooling tower performance is created to give a more accurate prediction of energy savings for a tower. Further the economic feasibility of having additional cooling tower capacity to allow for economizer cooling, in light of reduced tower capacity at lower temperatures is investigated.
43

Clean water for all: The demographics of urban and rural safe drinking water challenges in Virginia, USA and San Rafael Las Flores, Guatemala

Marcillo, Cristina Elizabeth 14 April 2020 (has links)
The United Nations established Sustainable Development Goal 6, universal access to safely managed drinking water and sanitation service, as a global goal for 2030. In rural areas, access lags significantly and progress is rarely examined concurrently between developed and developing nations. Therefore, this dissertation focuses on rural water system challenges in a developed nation, the US, and a developing nation, Guatemala. In the US, approximately 250 million Americans receive drinking water from community water systems (CWSs), theoretically safeguarded by the Safe Drinking Water Act (SDWA). There is mounting evidence that racial, ethnic, and socioeconomic disparities persist in US drinking water access and quality, but studies are limited by the exclusion of very small CWSs and a large geographic unit of analysis. A novel geospatial methodology was created to delineate system service areas at the zip code scale in Virginia and assess the influence of demographic characteristics on compliance with the SDWA from 2006 to 2016. Results reveal that monitoring and reporting violations are concentrated in private, rural systems that serve fewer than 500 people, while health-based violations were more likely in non-white communities, specifically those with higher proportions of Black, Native Hawaiian, and other Pacific Islanders. This study was completed in parallel with a household sampling campaign in rural San Rafael Las Flores, Guatemala. In Guatemala, no public access to water system compliance or quality information currently exists. With growing investment in mining industries and recognized naturally occurring arsenic in volcanic geology, citizens are eager for drinking water information. Survey results highlighted dissatisfaction with and distrust in most tap water sources. Consequently, residents regularly buy bottled water or collect water from untreated natural springs. Water quality results indicated that tap water from the central drinking water treatment plant contained higher levels of arsenic and other contaminants, when compared to most other sources. Though the settings are quite different, parallel investigation of rural drinking water system challenges in the US and Guatemala reveal common challenges and lessons. Moving forward, all nations would benefit from standard monitoring of drinking water access, quality, and compliance that allowed for intersectional investigations of environmental health inequities. / Doctor of Philosophy / In 2015, the United Nations established Sustainable Development Goal 6 which establishes safely managed drinking water and sanitation service for all as a global goal. Access to safe drinking water lags significantly in rural areas and can be complicated by intersecting social determinants of health (e.g. race, wealth). Rarely is progress in developed and developing nations examined concurrently, hindering an understanding of commonalities and an exchange of lessons. To this end, my dissertation focuses on rural water system challenges in a developed nation, the United States, and a developing nation, Guatemala. In the US, more than 250 million Americans receive in-home drinking water from one of 53,000 community water systems, with quality theoretically protected by the Safe Drinking Water Act (SDWA). Recent failures, such as the lead crisis in Flint, MI, have cast doubt on the equity and reliability of these utilities, especially in underserved areas. How can we ensure that all US communities receive equal protections under the Safe Drinking Water Act? Using publicly available data and geography, this work estimated service areas to determine whether SDWA violations related to surrounding community socio-demographics and/or system design. Results reveal that monitoring and reporting violations are significantly concentrated in private, rural systems that serve fewer than 500 people, while health-based violations were more likely in non-white communities, specifically those with higher proportions of Black, Native Hawaiian, and other Pacific Islanders. These findings illustrate potential issues of environmental justice within VA and advocate for future research to investigate potential structural causes. This work was completed in tandem with a household sampling campaign in rural San Rafael Las Flores, Guatemala. In Guatemala, there is currently no public access to water system compliance or quality information. With recognized naturally occurring carcinogenic elements in Guatemala's volcanic geology, such as arsenic, and heightened investment in extractive industries such as mining, that can compromise source water quality, citizens are eager for drinking water quality data. Survey results documented widespread dissatisfaction with and distrust in tap water quality. As a consequence, residents regularly buy bottled water or collect water from natural springs. Water quality results showed that tap water sourced from the central drinking water treatment plant contained significantly higher levels of arsenic and other contaminants when compared to most other tap sources. Community participation in long-term water monitoring and infrastructure decisions may help build trust in water sources. Though the regulatory, economic, and cultural settings are quite different, parallel investigation of rural drinking water system challenges in the US and Guatemala reveal common challenges and lessons. Moving forward, high, middle, and low-income nations all benefit from standard monitoring of drinking water access, quality, and compliance that allows for intersectional investigations of environmental health inequities.
44

Trigenerace a její využití v praxi / Trigeneration and its use in practice

Čupera, Pavel January 2009 (has links)
e master's thesis clarifies the concept of trigeneration and the principle of absorbing cooling. Compare the advantages and disadvantages of this method of manufacture cool with compressor cooling. It presents an overview of the implementation of a developing cold absorption and performance. Acquainted with the types of absorption chillers of the two leading suppliers, their characteristics and existing applications of these refrigeration units in operation in the Czech Republic and abroad. It also assesses the possibility of using these units in conjunction with a cogeneration unit powered by internal combustion engine. It follows from the economic assessment of costs and income of the absorption chillers and compressor chillers and on concrete examples and an assessment of the effectiveness of the various options.
45

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.
46

Avaliação de um sistema industrial de resfriamento de água. / Evaluation of an industrial system of cooling water.

Oikawa, Eduardo Hiroshi 19 March 2012 (has links)
Neste trabalho, foi estudado o desempenho de um sistema constituído de torres de resfriamento e a sua integração em uma planta industrial de hidrogenação de butadieno. Caracterizou-se o desempenho das torres de resfriamento com base em um modelo fenomenológico, cujos parâmetros foram obtidos a partir da medição de variáveis operacionais reais. O processo de hidrogenação foi configurado em um simulador de processos, sendo o caso base estabelecido nas condições de projeto. Elaborou-se um módulo específico referente às torres de resfriamento, que foi integrado ao processo configurado no simulador. Em seguida, analisaram-se as interações das condições operacionais da torre de resfriamento no desempenho do processo industrial. / In the present work, the performance of a system composed of a cooling tower integrated in butadiene hydrogenation plant was studied. An experimental investigation was made to characterize the cooling towers based on a phenomenological model and in real process conditions. The hydrogenation process was configured on a process simulator and design specifications were considered as base case. A cooling tower module was developed and integrated to the process simulator. The interaction of the cooling tower system and the plant operation was investigated.
47

An Approach To Urban River Rehabilitation For Coexistence Of River And Its Respective City: Porsuk River Case And City Of Eskisehir

Simsek, Gul 01 July 2011 (has links) (PDF)
All living things mostly the humans, as builders of civilizations, have always been in intrinsic bonds with water. This interaction between water (oceans, seas, lakes, rivers etc.) and settlements has existed since ancient civilizations. Among water resources, &lsquo / flowing waters&rsquo / such as rivers, streams, creeks, etc. have a prominent role as they are the lifeblood of most cities in terms of providing transportation, security, energy, irrigation, commerce, and recreation. By the late 19th century, developments of terrestrial transportation modes diminished the magnetism of rivers and riverfronts, and growing industries led to the deterioration of rivers. Owing to these reasons, along with many others, they turned into sewage channels, were covered up, and became water scopes detached from the urban life. Particularly since the 1970s, with more attention given to sustainability of resources, a greater awareness has grown of the vital role of urban rivers as a resource for humans and a lifeline for cities. After being neglected for decades, urban rivers have started to be rehabilitated to solve the related problems. The new approach to urban river rehabilitation beyond classical practices that aim at recovering the physical conditions of rivers has come to the fore to address the problems comprehensively. Instead of independent and one-dimensional practices, the urban rivers have become to be seen as a vital part of urban water system and of the city itself. While rehabilitating urban rivers, recovering river health can be ensured provided that the entire urban water ecosystem is taken into consideration. The ecocity approach is one of the major new approaches that geared toward achieving a healthy city, and sustainability of water system is the significant goal within this approach. In this regard, the thesis first asserts that the ecocity criteria are likely to give way to a more sustainable future for urban rivers. Besides being a part of the ecosystem, urban rivers have transformed together with the surrounding built environment throughout the history of cities. Significant focal elements of the urban pattern, urban rivers should be dealt with other urban focal points, with the introduced concept of river-city integration, which is proposed as the second assertion of the thesis. In this respect, the study attempts to investigate urban rivers and their rehabilitation in relation with both the ecocity approach, and the river-city integration concept. The research methodology in the present study involves comparative anaysis of best practices and case study analysis. Porsuk River and the city of Eskisehir, which the river passes through, were selected as a case for empirical study. Criteria sets that determined within the frames of ecocity and river-city integration, and the testing of the criteria in the case area offers an opportunity to contribute to literature of river and city coexistence.
48

Beyond the Aquifer : planning for San Antonio's future water supply

Laughlin, Nathan Daniel 24 November 2010 (has links)
This report examines water supply planning issues in San Antonio, Texas. San Antonio is unique among large cities in the United States in that it relies almost exclusively on a single source, the Edwards Aquifer, for its water supply. Because San Antonio’s water demand is projected to outgrow the Aquifer’s capacity, the city must consider other options to extend and augment its current water supply. After describing the hydrogeology and water supply history of San Antonio, this report explains the multitiered water planning structure and current and future water needs for the city. It then studies and evaluates three short-to-mid term water supply options. By continuing to develop its already successful water conservation programs and water reclamation system, San Antonio can delay the need for more costly and environmentally impactful water supply options down the road, and wisely manage the resources it already draws from. / text
49

Sistemas urbanos de água: avaliação de método para análise de sustentabilidade ambiental de projetos.

Figueiredo, Glauco Antônio Bologna Garcia de 31 March 2002 (has links)
Made available in DSpace on 2016-06-02T20:00:59Z (GMT). No. of bitstreams: 1 DissGABGF.pdf: 1168919 bytes, checksum: 5faa2f15b8855bdc75ae713156b8294a (MD5) Previous issue date: 2002-03-31 / Financiadora de Estudos e Projetos / The sustainable development concept has been used as a basic framework of urban planning processes. Due to its subjective components there were cases where the sustainability principles were used as marketing instruments, instead of an objective planning tool. As an attempt to reverse this situation the group for Sustainable and Strategic Urban Planning, from the São Carlos Federal University, studies way to apply sustainable development principles in the assessment and analysis of urban projects. In this thesis it was created a Method, which can be used in the evaluation of components of urban water system projects (water supply, wastewater collection and treatment, urban drainage, etc.). The Method is based on defined parameters and uses descriptive lists, flowcharts and interaction matrices to indicate sustainability tendencies (positive, negative or neutral). This model was applied in five different projects, which indicated some adjustments. The model was considered simple and effective. Another advantage of the Method is its modular character: new information and tools can be added, in order to obtain more complex analysis. Besides that, it can be used to evaluate the planning or performance of other sustainable systems. / O conceito de sustentabilidade tem sido proposto e utilizado como referência para o planejamento das atividades humanas e a democratização de decisões na sociedade. Entretanto, nem sempre é abordado de forma objetiva, e sua característica subjetiva permite que, muitas vezes, seja usado apenas como instrumento de propaganda. Visando contribuir para alterar esse quadro, vêm sendo desenvolvidos, pelo Grupo de Planejamento Estratégico e Sustentável do Meio Urbano (PESMU) da UFSCar, estudos para a obtenção de métodos que incorporem a questão da sustentabilidade na análise e avaliação de projetos no contexto urbano. No presente trabalho, é feita a avaliação de um Método desenvolvido para análise da sustentabilidade ambiental em projetos de sistemas urbanos de água (abastecimento, esgotamento, drenagem). Baseando-se em variáveis de controle previamente definidas, o Método faz uso de fichas de caracterização, fluxogramas e matriz de interação utilizadas em conjunto, apontando tendências favoráveis, desfavoráveis ou neutras de sustentabilidade ambiental. Foram feitas as aplicações práticas do Método em diferentes tipos de projetos e, a partir de uma análise dos resultados, foram propostos ajustes no mesmo. A utilização do Método mostrou-se viável, mesmo com algumas limitações detectadas. Entretanto, podem vir a ser incorporadas novas informações e ferramentas mais complexas, ampliando suas possibilidades de aplicação, principalmente para o planejamento de sistemas e o acompanhamento de seu desempenho, além de poder ser aplicado nas demais dimensões da sustentabilidade.
50

Assessing the environmental impacts of a complex urban water system based on the life cycle assessment framework : development of a versatile model and advanced water deprivation indicators / Évaluation des impacts environnementaux d'un système d'eau urbain complexe dans le cadre de l'analyse du cycle de vie (ACV) - Développement d'un modèle polyvalent et d'indicateurs de privation d'eau avancés : développement d'un modèle polyvalent et d'indicateurs de privation d'eau avancés

Loubet, Philippe 27 November 2014 (has links)
La gestion intégrée de l'eau à l'échelle des grandes villes est un réel défi. Cependant, la quantification des flux et des impacts environnementaux liés à l'utilisation de l'eau n'est pas encore suffisamment développée. Dans ce contexte, la question de recherche de la thèse est: "comment modéliser le système d'eau urbain complexe d'une mégapole pour l'évaluation de ses impacts sur l'environnement et des services fournis aux usagers de l'eau, dans le cadre de l'analyse du cycle de vie (ACV)?" Le cœur de la thèse est le développement d'un cadre général définissant les flux d'eau et les impacts environnementaux associés aux trois composants principaux du système d'eau urbain, à savoir, les technologies de l'eau, les usagers de l'eau et les ressources en eau. Le modèle proposé de système d'eau urbain (nommé WaLA) se construit à travers une approche modulaire permettant l'interopérabilité des trois composants. Le modèle fournit des indicateurs d'impacts et de services rendus qui peuvent être utiles aux décideurs et aux parties prenantes. Il simplifie l'évaluation des scénarios et diminue la complexité du système tout en assurant sa bonne représentation du point de vue de l'ACV. En plus de cet objectif principal, la thèse vise à raffiner les indicateurs d'impact sur la privation d'eau afin qu'ils soient pertinents pour les systèmes d'eau urbains. Une méthode qui permet d'évaluer la privation d'eau à l'échelle du sous bassin versant en intégrant les effets en aval a ainsi été développée. Cette méthode permet de différencier les impacts selon les points de prélèvements et de rejets dans un même bassin versant. Enfin, le modèle WaLA et les indicateurs associés sont mis en œuvre pour évaluer les impacts environnementaux du système d'eau urbain de la banlieue parisienne (périmètre du Syndicat des Eaux d'Ile-de-France). L'intérêt et l'applicabilité du modèle pour évaluer et comparer des scénarios actuels et prévisionnels sont ainsi démontrés. / To improve water management at the scale of large cities is a real challenge. However, the quantification of flows and environmental impacts linked to water use are not yet sufficiently developed. This is the objective of the thesis: “how to model complex urban water system of a megacity for assessing its environmental impacts in relation to the provided services to water users, within the life cycle assessment (LCA) framework?” The core of the thesis is the development of a generic framework defining water flows and environmental impacts associated with 3 categories of items – i.e., water technologies, water users and water resources – from a LCA point of view. The UWS model (termed WaLA) is built through a modular approach allowing the interoperation of these three components in an integrated way. The model provides indicators of impacts on services which may be useful to decision makers and stakeholders. It simplifies the evaluation of forecasting scenarios and decreases the complexity of the urban water system while ensuring its good representation from a LCA perspective. In addition to this main objective, the thesis also aims at refining water use impact indicators at a relevant scale for UWS. A methodology that assesses water deprivation at the sub-river basin scale in life cycle impact assessment (LCIA) integrating downstream cascade effects has been developed. It allows differentiating the withdrawal and release locations within a same river basin. The WaLA model and its associated indicators are applied to assess the environmental impacts of the water system of a Paris suburban area (perimeter of Syndicat des Eaux d'Île-de-France). It shows the interest and the applicability of the model for assessing and comparing baseline and forecasting scenarios.

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