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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.
201

Monitoring biostability and biofilm formation potential in drinking water distribution systems

Useh, Kowho Pearl January 2017 (has links)
A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. August, 2017 / The foremost aim of potable water treatment is to produce water that does not pose a health risk when consumed and/or otherwise used. Nevertheless, research has established that the quality of treated water deteriorates during distribution. The nature and extent of this deterioration varies from system to system and from time to time. The aim of this research study was to monitor the parameters that are known to significantly affect biostability and biofilm formation potential in drinking water distribution systems. Biweekly water samples were collected from thirteen sites, across a section of Johannesburg Water’s network, between September 2015 and August 2016. All samples were assayed for a suite of fifteen water quality parameters using standard methods. Heightened temperature, dearth of chlorine residuals, availability of biodegradable dissolved organic carbon (BDOC), and advanced water age all engendered the loss of biostability (instability). Biostability controlling parameters varied seasonally and spatially. Samples collected during spring and summer, in general, were most likely to be characterized by instability than samples collected during winter and autumn. Samples collected from sites RW80, RW81, RW82, RW83, RW104 and RW253 were more prone to instability compared to samples from other sites. From the results, it is clear that chlorine residuals ought to be kept above 0.2 mg/l, and, BDOC below 0.3mg/l to prevent the loss of heterotrophic stability in distributed water. BDOC concentrations can be decreased by, flushing the pipes, cleaning reservoirs regularly and by further treating feed water before distributing. Booster disinfection can be relied upon to ensure that chlorine residuals are maintained throughout the network. Apart from potential health risks, biological instability and biofilm growth can result in non-compliance with regulations. / MT2018
202

Análise da sustentabilidade ambiental do sistema de classificação das águas doces superficiais / Analysis of environmental sustainability of the superficial freshwater classification system

Pizella, Denise Gallo 22 August 2006 (has links)
O Brasil é um país dotado de grandes reservas hídricas superficiais e biodiversidade aquática, apesar de sua distribuição desigual entre as diversas regiões hidrográficas. Tendo em vista o conceito de desenvolvimento sustentável presente em diversos tratados internacionais de meio ambiente e recursos hídricos, objetivados à preservação dos ecossistemas aquáticos juntamente com a distribuição eqüitativa dos benefícios advindos da utilização dos recursos hídricos, a política nacional de recursos hídricos (Lei n° 9433/97) estabeleceu os objetivos e os instrumentos regulatórios e econômicos que norteiam a gestão hídrica brasileira, tendo por pressuposto a utilização sustentável destes recursos. Dentre os instrumentos criados para tanto, destacam-se neste trabalho a definição de padrões de qualidade para as águas superficiais, regulamentada pela Resolução CONAMA nº 20/86 e revogada pela Resolução CONAMA nº 357/05, e o enquadramento dos corpos de água superficiais, regulamentado pela Resolução CNRH n° 12/00. A partir do conhecimento sobre os novos paradigmas que estruturam os sistemas de gestão da qualidade hídrica em países com tradição em sua implementação, procurou-se desenvolver uma análise crítica do sistema de gestão da qualidade hídrica brasileiro, com enfoque para os sistemas de classificação das águas doces superficiais, considerando-se os objetivos e critérios de qualidade hídrica adotados e os sistemas de monitoramento. Para a realização dos objetivos propostos, procedeu-se à revisão bibliográfica dos documentos balizadores dos objetivos da gestão hídrica em âmbito mundial, buscando-se identificar os princípios que norteiam os sistemas de gestão da qualidade hídrica em escala global; análise dos sistemas de gestão da qualidade hídrica em países de referência, como Estados Unidos da América, Canadá, União Européia, Reino Unido, França, Austrália e Nova Zelândia, com intuito de identificar as novas tendências de gestão da qualidade hídrica; análise do sistema de gestão da qualidade hídrica brasileira nos aspectos de disponibilidades e demandas, organização institucional e legal, objetivos, parâmetros e padrões de qualidade, sistema de classificação e enquadramento dos corpos de água doce superficiais, buscando-se identificar os principais problemas e desafios de gerenciamento. Constataram-se entraves de ordem técnica, legal, econômica, social e institucional, como: falta de articulação entre os instrumentos das políticas hídrica e ambiental e entre órgãos gestores; dificuldades no estabelecimento de comitês e as agências de bacias, indispensáveis para a eficácia do sistema; incongruência entre objetivos de qualidade hídrica protetivos e a existência de classes de qualidade permissivas; desenvolvimento de padrões de qualidade hídrica considerando apenas as características físico-químicas e microbiológicas da água, em detrimento de suas características ecossistêmicas; além da defasagem no sistema de informações ambientais e no monitoramento da qualidade hídrica em todo o território. A partir do diagnóstico realizado neste trabalho, buscou-se levantar recomendações para o aperfeiçoamento do sistema tendo em vista o cumprimento dos objetivos de sustentabilidade ambiental das políticas ambiental e hídrica brasileiras. / Brazil is a country endowed with great superficial water reserves and aquatic biodiversity, despite its unequal distribution among diverse hydrographic regions. In view of the sustainable development concept established in many international environment and water treated, objectified to the aquatic ecosystems preservation and the equitable distribution of the water uses benefits, the national water policy (Law nº 9433/97) determined the objectives and the regulatory and economic instruments that guide the sustainable use of these resources. Among these instruments, are distinguished in this work those directly related to the water quality management, as the definition of superficial water quality standards, regulated in CONAMA Resolution nº 20/86 (revoked by CONAMA Resolution nº 357/05), and the superficial water bodies framing, regulated in CNRH Resolution nº 12/00. From the knowledge on the new paradigms that structuralize the water quality management systems in countries with tradition in its implementation, it was looked to develop a critical analysis of the brazilian water quality management system, under the institutional point of view and of the instruments legally constituted to implement it, with approach for the superficial freshwater classification systems, considering the objectives and criteria of water quality adopted and the monitoring systems. For the accomplishment of the objectives considered in this work, it was proceeded the bibliographical revision from documents makers of the water management objectives in a world-wide scope, searching to identify the principles that guide the water quality management systems in a global scale; analysis of water quality management systems in reference countries, as United States of America, Canada, European Union, United Kingdom, France, Australia and New Zealand, with intention to identify the new trends of water quality management; analysis of brazilian water quality management system in the aspects of availabilities and demands, institutional and legal organization, objectives, parameters and water standards, classification system and superficial freshwater framing, searching to identify the main problems and challenges of management. There were evidenced technical, legal, economic, social and institutional impediments, as: articulation lack between water and environment policies instruments and between managing agencies; difficulties in the establishment of committees and basins agencies, indispensables for the system effectiveness; incongruity among water quality protective objectives and the existence of permissive quality classes; development of water quality standards considering only the water microbiological and physicist-chemistries proprieties, disrespecting its ecosystem characteristics; beyond the imbalance in the environment information and water quality monitoring systems in all country. From the diagnosis carried through in this work, one searched to raise recommendations for the perfectioning of the system in view of the fulfilment of Brazilian water and environmental policies sustainability objectives.
203

Land-use on water quality of the Bottelary River in Cape Town, Western Cape

Itoba Tombo, Elie Fereche January 2010 (has links)
Thesis (MTech (Environmental Management))--Cape Peninsula University of Technology, 2010 / Freshwater scarcity and river pollution has become a serious challenge for governments and scientists. Worldwide, governments have a responsibility to provide their populations with enough clean water for their domestic needs. Scientists will have an enormous task to find a way to purify polluted water, because of its vital role in human lives and an increasing demand for water consumption due to population growth. Although the water from the Bottelary River is used on a daily basis for farming activities, its pollution level as well as spatial distribution of effluents in the catchment is unknown. In the present study, I took monthly water samples from six sampling points for laboratory analysis. The laboratory determined concentration levels of phosphorous, chloride, nitrate, and nitrate nitrogen (N03N), as well as the chemical oxygen demand (COD) and suspended solids from the samples. On the same occasion's pH, dissolved oxygen, electrical conductivity and temperature were measured in-situ using a multi-parameter reader. The results were then compared with the South African Water Quality Guidelines for Aquatic Ecosystems and for irrigation (DWAF, 1996a, 1996c). The non-point pollution source (NPS) model was used to generate predictions of the pollution level from the land-uses and use the data obtained from the field to validate the model predictions. Finally, I performed a two-factorial A One-way Analysis of Variance (ANOVA) without replication to assess the spatial and temporal variation of the measured variables along the river. The findings of the study have shown that the concentration levels of some compounds are below the Target Water Quality Range (TWQR) set by the Department of Water Affairs and Forestry (DWAF, 1996a, 1996b, 1996c) while, the concentrations of chloride, total nitrogen and water quality variables such as electrical conductivity, suspended solids, are higher than the TWQR (DWAF, 1996a, 1996b, 1996c). Based on the above findings water of the Bottelary River can have negative effects on the environment and human lives because of the concentration level of these compounds. It was therefore recommended that, environmentally friendly measures and practices must be undertaken in order to decrease the pollution and avoid further pollution of the river.
204

Ecological water quality assessment and science-driven policy : investigating the EU Water Framework Directive and river basin governance in China

Mao, Feng January 2015 (has links)
No description available.
205

Assessing a Fluorescence Spectroscopy Method for In-Situ Microbial Drinking Water Quality

Sharpe, Taylor Jeffery 11 August 2017 (has links)
Waterborne disease is a significant contributor to the global burden of disease, in particular among high-risk populations in developing nations. State-of-the-art methods for the enumeration of microbial pathogens in drinking water sources have important limitations, including high initial cost, 24-48 hour delays in results, high staffing and facility requirements, and training requirements which all become especially problematic in the developing nation context. A number of alternative approaches to microbial water quality testing have been proposed, with the goal of decreasing the required testing time, decreasing overall costs, leveraging appropriate technology approaches, or improving sensitivity or specificity of the water quality testing method. One approach that may offer solutions to some of these limitations involves the deployment of sensor networks using fluorescent spectroscopy to detect intrinsic protein fluorescence in water samples as a proxy for microbial activity. In recent years, a number of researchers have found significant and meaningful correlations between indicator bacteria species and the protein fluorescence of drinking water samples. Additionally, advances in the semiconductor industry could be used to drive down the cost of such sensors. This technology may also be extensible to other water quality parameters, including dissolved organic matter or the presence of fluorescent pollutants. In this thesis, a literature review describes the fundamentals of fluorescence spectroscopy, historical and recent work regarding the fluorescence of the amino acid tryptophan and associated bacterial fluorescence, possible mechanisms for this association, and potential applications of this technology for drinking water quality monitoring and waste water process control. Extensibility of the technology is also discussed. Next, experimental methodology in reproduction of similar results is described. Samples were taken from seven (7) surface water sources and tested using membrane filtration and an off-the-shelf fluorescence spectrometer to help examine the association between the presence of indicator bacteria and the tryptophan fluorescence of the water sample. The results, showing an association of R2 = 0.560, are compared to the results of recent similar experiments. Finally, two prototypes are described, including their design requirements and data from prototype testing. The results of the testing are briefly discussed, and next steps are outlined with the goal of developing a low-cost, in-situ microbial water quality sensor using fluorescence spectroscopy principles.
206

Parameter estimation using a genetic algorithm for complex catchment modelling systems.

Fang, Tianjun, Civil & Environmental Engineering, Faculty of Engineering, UNSW January 2007 (has links)
Implementation of physically distributed catchment modelling systems reshapes the fundamental philosophy of traditional calibration approaches by supporting the concept of equifinality. Arising from the concept of equifinality, alternative behavioural parameter sets within a given catchment modelling system structure can generate similar levels of simulation performance. This concept is motivated by the existence of a variety of uncertainties associated with a complex catchment modelling system, such as an imperfect model structure, measurement errors in both the input data and the recorded flows, and unknown, or poorly defined, interactions among parameters. However, the difficulty of searching for behavioural parameter sets increases as the complexity of the catchment modelling systems increases. This study undertook an investigation on the feasibility and robustness of a real-value coding genetic algorithm (GA) for calibrating the physically distributed Storm Water Management Model (SWMM) using the Centennial Park catchment in Sydney as a case study. It was found that a real-value coding GA was a robust technique suitable to search for behavioural parameter sets and, in particular, it was found that this approach was capable of identifying the promising range of values for spatially variable parameters. Moreover, the widespread use of physically distributed catchment modelling systems has highlighted the importance of estimating the uncertainty in the parameter values and in the predictions obtained from a complex catchment modelling system as well as in catchment averaged, or lumped, systems that have been the focus of many previous studies. Bayesian inference has been shown to be a tool suitable for parameter uncertainty estimation in catchment modelling. However, the application of Bayesian inference faces difficulties in complex high-dimensional systems where there is little if any a priori knowledge about the proposal distribution of the parameters. In this study, a real-value coding GA was used to undertake uncertainty estimation on spatially variable control parameters with little a priori knowledge about the proposal distribution of parameters. After 50,000 evaluations, the marginal posterior distributions of spatially variable parameters which are associated with behavioural parameter sets were identified. The performance of a behavioural parameter set under a range of hydrological conditions was evaluated. Updating of the marginal distributions of these control parameters was implemented by adding additional calibration data. Interactions among the spatially variable control parameters were investigated also. Results based on the Pearson Correlation method indicate no clear relationship between any two control parameters. However, a methodology to detect relationships among groups of parameters was developed. Application of this methodology suggests that the simulation performance of SWMM was influenced by combinations of parameter values rather than values of the individual parameters. Finally, the predictive uncertainty associated with the existence of behavioural parameter sets was considered. A number of alternative strategies were used to evaluate the predictive performance. Consideration of the results suggests that use of a small number of parameter sets randomly selected from the large number of behavioural parameter sets was the best strategy in terms of efficiently obtaining predictive performance.
207

The role of water quality modelling in decision-making

McNamara, Leslie, University of Western Sydney, College of Health and Science, School of Natural Sciences January 2007 (has links)
Catchment management organisations often use computer-based water quality models to support their decision-making needs. However, literature suggests that model use by catchment managers can be highly problematical. Commonly reported issues that negatively impact upon the effectiveness of modelling for decision-making are data quality and availability, miscommunication between analysts and decision-makers, inappropriate treatment of uncertainty, excessive model complexity (‘sophistication’) or simplicity and poor modelling practice. The challenges that beset catchment managers are usually framed as technical problems that can be overcome by using or communicating the science that underlies the models more effectively. As a result, many of the problems associated with the use of models by catchment managers have not been adequately elucidated from the standpoint of a manager. This thesis examines the problem of modelling for decision-making from a fresh perspective. Systemic approaches to research are commonly used where the research problem is ill-defined, as it is here. ‘Action research’ is one qualitative, systemic methodology, and was used here as the guiding methodology to explore the model related problems faced by catchment managers. Action research involves recurrent cycles of planning, action, observation and reflection. The research was undertaken with the Sydney Catchment Authority (SCA), a New South Wales government agency responsible for water quality and catchment health in the drinking water catchments of Sydney, Australia. The SCA had expressed a particular need for tools to support the assessment of development applications with respect to potential impacts on water quality, and to prioritise rural land for remedial action to improve water quality in the drinking water catchments. The research had two broad aims that were:1.to develop two models differing in sophistication, and to use them to prioritise nutrient pollution sources and calculate nutrient loads; And, through the participatory development of the models, 2.to learn methodological lessons that catchment managers can apply to choose and use models more effectively. In this research, action was in the form of five planned activities, including: i. a review of relevant literature from diverse disciplines; ii. the holding of two workshops; the first exclusively involving SCA managers to identify their modelling needs, and the second involving water quality scientists and modelers to discuss methods for meeting the modelling needs; iii. the development and use of two export coefficient nutrient models; iv. a focus group discussion involving key staff in the SCA; and v. a review of published guidelines for good modelling practice in environmental management. Note was also taken of statements or behaviour at numerous meetings and seminars, mostly with SCA staff, that were relevant to the research questions. / Doctor of Philosophy (PhD)
208

Best practices in drinking water quality regulation elements of an Australian model

Moeller, Anthony. January 2001 (has links) (PDF)
Includes bibliographical references (p. 319-347) Mode of access: Internet via World Wide Web. Available at: http://business.unisa.edu.au/waterpolicylaw/documents/thesis.pdf Selected for archiving SSL
209

Geo-chemical budget models of the Penrith Lakes Scheme

Keogh, Andrew James, University of Western Sydney, College of Science, Technology and Environment, School of Engineering and Industrial Design January 2003 (has links)
The Penrith Lakes Scheme is a series of inter-connected lakes, produced by the rehabilitation of a sand and gravel quarry, for water quality treatment and recreational uses. Presently, 5 lakes are operational comprising 4 upstream lakes for treatment of storm-water and quarry discharge and a single downstream recreational lake as the Sydney International Regatta Centre used during the Sydney 2000 Olympic Games. This report is the result of a study, during 1998-2003, with an aim to develop dynamic budget models of water, sediments and nutrients for these lakes, providing suitable data for long-term management planning and evaluation of short-term operational management.Findings showed that while progressive reassessment and refinement will be required as management control increases, the approach provides the foundation modelling procedures and frame-work for suitable hydrological and water quality management of the Penrith Lakes Scheme, and may be extended to include further lakes, water sources and management strategies. / Doctor of Philosophy (PhD)
210

A catchment approach to managing agricultural pesticides in the environment : a case study with the herbicide atrazine

Popov, Vladislav H., University of Western Sydney, College of Science, Technology and Environment, School of Environment and Agriculture January 2005 (has links)
Surface water quality of the Liverpool Plains (NSW), a series of floodplains comprising the floodplain of the Mooki River, is poor despite the introduction of conservation tillage that has reduced soil erosion and, with it, the transport of sediment, nutrients and chemicals to streams.The aim of this thesis was to provide a basis for recommending the possible wider use of biofilters, by determining their effectiveness in reducing pollutant (mainly atrazine) transport at multiple scales in the Liverpool Plains, quantifying the importance of relevant processes, including the capacity of soil biofilters to degrade the retained pollutants, and evaluating the effect of pollutants on the biofilter vegetation. These objectives were explored in two sub-catchments within the Liverpool Plains, namely Big Jacks Creek and the Blackville.Soils are predominantly vertosols that crack deeply on drying, resulting in initially high infiltration rates on wetting and high water holding capacity. Field monitoring revealed that biofilters such as grassed waterways, natural grasslands or vegetated filter strips (VFS) positioned at multiple catchment scales can significantly reduce pollutant concentrations in runoff. The use of biofilters is discussed, along with other best management practices that will be needed to manage pesticide loads both at source and in the transport pathway. / Doctor of Philosophy (PhD)

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