The diploma thesis deals with the rate of free chlorine dacay in the water supply systems. In the general part of the work are mentioned the forms of chlorine that can be encountered in its use for disinfection of drinking water. Another chapter is the modeling of chlorine decomposition in water during pipeline distribution. This chapter deals with the kinetic reactions of chlorine and their orders, and subsequently with factors influencing the rate of chlorine loss. Closer deals with pipe wall chlorine decay and the bulk water flow chlorine decay. The second part of the diploma thesis is focused on determining the constant kb, which is the rate coefficient of loss of chlorine in the pipeline caused by the flow of water. The work contains several researches of various world studies that deal with this issue. The following is a step-by-step guide to performing this test. The last part deals with the case studies at the waterworks in Kateřinice and Brno. On these tapes the chlorine concentration was measured over time and a constant kb was determined based on these results, expressing the rate of free chlorine decay in bulk water flow.

While free (breakpoint) chlorination is widely utilized in humanitarian water treatment, a main challenge limiting its effective application is in determining the initial dose to satisfy both health requirements and aesthetic considerations (i.e. taste and odour). International guidelines and studies showed varying recommendations for the initial chlorine dose and many did not consider chlorine decay during water transportation and storage for up to 24 hours. The main objective of this thesis is to develop a tool for humanitarian staff to accurately determine the initial chlorine dose for achieving free chlorine residual (FCR) objectives with the limited instrumentation and information in the field. The first manuscript included in the thesis gathered and evaluated seven basic chlorine decay models’ applicability in humanitarian treatment contexts. All seven models were found able to accurately describe chlorine decay in water representative of humanitarian treatment contexts with more than half of the regression resulted in R2 over 0.95. However, each model had its own limitations, which were discussed. The second manuscript involved conducting extensive chlorine decay tests in water with different characteristics, explored the relationships between the estimated chlorine decay constant and several water parameters including pH, turbidity, ultraviolet absorption at 254 nm wavelength (UVA254), temperature and 30-minute chlorine demand. It was found that the UVA254 of water followed linear and exponential relationships with the decay constant in Feben and Taras’s empirical model and that in the first order model respectively. Arrhenius-type relations were verified between the decay constant and water’s temperature. A model developed to predict FCR decay in water with known 30-minute chlorine demand accurately predicted FCR level in synthetic water (with humic acid being the main constituent) but underpredicted FCR decay in water with additional chlorine consuming matter. Further research on additional chlorine decay mechanisms are needed to expand the applicability of the model. / Graduate / 2021-04-13

No description available.

No description available.

O uso do cloro como desinfetante em sistemas de água para abastecimento é prática comum nas estações de tratamento de água. Introduzido durante o processo de tratamento, o cloro participa de diversas reações com compostos de naturezas orgânicos e inorgânicos no interior das tubulações. Tais reações ocorrem na massa líquida e junto às paredes das tubulações e são responsáveis pelo decaimento do cloro ao longo das redes. Visualizando a modelagem como uma ferramenta eficiente para gerenciar o cloro residual em sistemas de distribuição de água, muitos estudos foram realizados e reportados pela literatura, assumindo que os efeitos de decaimento de cloro podem ser bem representados pelos coeficientes kb e kw. Entretanto, a determinação de valores para parâmetros em questão não é uma tarefa fácil, devido à complexidade dos sistemas enfocados em termos da diversidade de materiais das tubulações e mananciais (superficiais e subterrâneos). No Brasil, apesar de legislação recente estabelecer limites restritivos para o cloro na água potável (após desinfecção, a concentração de cloro deve observar a concentração mínima de 0,5 mg/L, sendo o mínimo nível aceito em sistemas de distribuição de 0,2 mg/L e o máximo de 2,0 mg/L), poucos estudos enfocam a avaliação dos parâmetros de decaimento. Esta pesquisa apresenta a aplicação de um modelo inverso elaborado para determinar a ordem para o modelo de decaimento do cloro e os valores globais e/ou locais para o kb e o kw. Sendo programado com o suporte do simulador de EPANET 2 (toolkit) e os algoritmos genéticos como ferramenta de otimização, implementado através da biblioteca de GAlib C++. Os estudos foram realizados em dois sistemas reais da distribuição da água em que foram considerados parâmetros globais e parâmetros específicos da qualidade. Para a investigação da determinação de parâmetros de decaimento de cloro em sistemas de distribuição com vazamento em função da pressão, foi adotada uma rede hipotética com três fontes de cloro. Esse sistema permitiu a calibração e a validação do modelo, assim como a avaliação da influência hidráulica na determinação dos resultados de qualidade de água. / The use of chlorine as disinfectant in water supply systems has been a common practice adopted by the water industry. Introduced during the treatment process, chlorine participates in several reactions with compounds of organic and inorganic nature inside the pipes. Such reactions that occur in the bulk and the wall of the pipes are responsible for chlorine decay along the networks. Visualizing the modeling as an efficient tool to manage the chlorine residual in water distribution systems, many studies have been conducted and reported by the literature, assuming that the chlorine decay effects can be well represented by the decay coefficients kb and kw. However, the determination of values for theses parameters is not an easy task, due to the complexity of the focused systems in terms of pipe materials and water supply sources diversity (surface water and groundwater). In Brazil, instead of recent legislation stating more strict limits for chlorine in drinking water (after disinfection, chlorine concentration has to observe the minimum concentration of 0.5 mg/L, being the minimum accepted level in the distribution system of 0.2 mg/L and the maximum of 2.0 mg/L), few studies focus on the evaluation of the decay parameters. This research reports the application of an inverse model built to determine the order for chlorine decay model and the global and/or local values for kb and kw. It is codified with the support of EPANET 2 (Toolkit) simulator and technology of genetic algorithms as optimization tool, which is implemented by using the GAlib C++ library. The studies were conducted on two real water distribution systems considering both global and specific quality parameters. A hypothetical network with three sources of chlorine was studied too, admitting leakage as pressure function. This system permitted both calibration and validation of the model as well as the evaluation of hydraulic calibration influence on the water quality results.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-08-13T11:23:42Z No. of bitstreams: 2 Dissertação - Luciano de Oliveira - 2018.pdf: 5027134 bytes, checksum: a0469fdd822b10eda9e451f4b9c889b2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-08-13T11:51:19Z (GMT) No. of bitstreams: 2 Dissertação - Luciano de Oliveira - 2018.pdf: 5027134 bytes, checksum: a0469fdd822b10eda9e451f4b9c889b2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-08-13T11:51:19Z (GMT). No. of bitstreams: 2 Dissertação - Luciano de Oliveira - 2018.pdf: 5027134 bytes, checksum: a0469fdd822b10eda9e451f4b9c889b2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-07-13 / The chlorination process is the most used to promote disinfection of water intended for human consumption. During the course of chlorinated water in the supply systems, the concentration of free residual chlorine (FRC), whose reaction rate depends on the characteristics of the natural water, occurs. In this work, we studied the decay of the FRC concentration related to the reactions in the liquid mass in two types of water, of subterranean and superficial origin, with different concentrations of organic matter, with the perspective of the influence of the water travel time, dependent on consumption scenarios in real distribution networks, whose supply modules are characterized by low population density and that operate under the initial demand conditions predicted in the projects. The effect of temperature and total organic carbon on the values of mass decay kinetic constants (k b ), used in mathematical models that simulate water quality, was considered. The results showed that the variation of the kb values is directly proportional to the water temperature and the TOC. For initial concentrations close to 1.00 mg.L -1 , the values of the kinetic constants for waters from surface water sources maintained in the temperature ranges of 20 to 21 °C and 30 to 31 °C were respectively 0.0888 day -1 and 0.1200 day -1 for samples collected at the ETA filter output of the DAIAsystem and TOC value of 0.4798 mg.L -1 and equal to and 0.1680 day -1 and 0.3024 day -1 for the samples collected at the filter outputs of the Piancó and TOC system ETA of 0.8750 mg.L - . In samples of groundwater with TOC of 0.1740 mg.L -1 , maintained at the same temperature 1 ranges, the kinetic coefficients were 0.0264 day -1 and 0.0480 day -1 , respectively. Experiments for temperature between 30 and 31 °C and near test duration showed a significant difference in chlorine decay behavior in filtered water samples collected at conventional treatment plants, which showed a residual chlorine loss percentage of 64.81% in relation to the initial concentration of 1.08 mg.L -1 of disinfectant (ETA DAIA) and 33.65% in relation to the initial concentration of 1.05 mg.L -1 of disinfectant (ETA Piancó). Raw water samples from the underground spring lost 14.33% of the initial concentration of 1.04 mg.L -1 . The travel times for the most critical nodes and the minimum disinfectant concentrations at the entrance of the supply modules to comply with the legislation were 40 hours and 0.27-0.28 mg.L -1 for the distribution networks of the condominium Valley of the Birds and 144 hours and 0.30-0.36 mg.L -1 for the condominium Terras Alphaville. / O processo de cloração é o mais utilizado para promover a desinfecção das águas destinadas ao consumo humano. Durante o percurso da água clorada nos sistemas de abastecimento ocorre o decaimento da concentração do cloro residual livre (CRL), cuja taxa de reação depende das características da água natural. Neste trabalho estudou-se o decaimento da concentração do CRL relacionado às reações na massa líquida em dois tipos de águas, de origem subterrânea e superficial, com diferentes concentrações de matéria orgânica, com aperspectiva da influência do tempo de percurso da água, dependente de cenários de consumo em redes de distribuição reais, cujos módulos de abastecimento são caracterizados pelo baixo adensamento populacional e que operam nas condições iniciais de demanda previstas nos projetos. Considerou-se o efeito da temperatura e do carbono orgânico total sobre os valores das constantes cinéticas de decaimento em massa (k b ), utilizadas nos modelos matemáticos que simulam a qualidade da água. Os resultados mostraram que a variação dos valores de k b é diretamente proporcional à temperatura da água e ao COT. Para concentrações iniciais próximas a 1,00 mg.L -1 os valores das constantes cinéticas, para águas provenientes de mananciais superficiais mantidas nas faixas de temperatura de foram, respectivamente, iguais a 0,0888 20 a 21 °C e 30 a 31 °C, dia -1 e 0,1200 dia -1 para amostras coletas na saída do filtro da ETA do sistema DAIA e valor de COT de 0,4798 mg.L -1 e iguais a e 0,1680 dia -1 e 0,3024 dia -1 para as amostras coletas na saídas do filtro da ETA do sistema Piancó e COT de 0,8750 mg.L -1 . Em amostras de água subterrânea com COT de 0,1740 mg.L -1 , mantidas nas mesmas faixas de temperatura, os coeficientes cinéticos foram iguais a 0,0264 dia -1 e 0,0480 dia -1 , respectivamente. Os experimentos para temperatura entre 30 e 31 °C e tempos próximos de duração dos testes demonstraram diferença significativa no comportamento do decaimento do cloro em amostras de água filtrada coletadas nas estações de tratamento convencional que apresentaram porcentagem de perda de cloro residual de 64,81 % em relação à concentração inicial de 1,08 mg.L -1 de desinfetante (ETA DAIA) e 33,65 % em relação à concentração inicial de 1,05 mg.L -1 de desinfetante (ETA Piancó). Amostras de água bruta do manancial subterrâneo perderam 14,33 % da concentração inicial de 1,04 mg.L -1 . Os tempos de percurso para os nós mais críticos e as concentrações mínimas de desinfetante na entrada dos módulo de abastecimento para atendimento à legislação foram iguais a 40 horas e 0,27-0,28 mg.L -1 para as redes de distribuição do condomínio Vale dos Pássaros e 144 horas e 0,30-0,36 mg.L -1 para o condomínio Terras Alphaville.

O uso do cloro como desinfetante em sistemas de água para abastecimento é prática comum nas estações de tratamento de água. Introduzido durante o processo de tratamento, o cloro participa de diversas reações com compostos de naturezas orgânicos e inorgânicos no interior das tubulações. Tais reações ocorrem na massa líquida e junto às paredes das tubulações e são responsáveis pelo decaimento do cloro ao longo das redes. Visualizando a modelagem como uma ferramenta eficiente para gerenciar o cloro residual em sistemas de distribuição de água, muitos estudos foram realizados e reportados pela literatura, assumindo que os efeitos de decaimento de cloro podem ser bem representados pelos coeficientes kb e kw. Entretanto, a determinação de valores para parâmetros em questão não é uma tarefa fácil, devido à complexidade dos sistemas enfocados em termos da diversidade de materiais das tubulações e mananciais (superficiais e subterrâneos). No Brasil, apesar de legislação recente estabelecer limites restritivos para o cloro na água potável (após desinfecção, a concentração de cloro deve observar a concentração mínima de 0,5 mg/L, sendo o mínimo nível aceito em sistemas de distribuição de 0,2 mg/L e o máximo de 2,0 mg/L), poucos estudos enfocam a avaliação dos parâmetros de decaimento. Esta pesquisa apresenta a aplicação de um modelo inverso elaborado para determinar a ordem para o modelo de decaimento do cloro e os valores globais e/ou locais para o kb e o kw. Sendo programado com o suporte do simulador de EPANET 2 (toolkit) e os algoritmos genéticos como ferramenta de otimização, implementado através da biblioteca de GAlib C++. Os estudos foram realizados em dois sistemas reais da distribuição da água em que foram considerados parâmetros globais e parâmetros específicos da qualidade. Para a investigação da determinação de parâmetros de decaimento de cloro em sistemas de distribuição com vazamento em função da pressão, foi adotada uma rede hipotética com três fontes de cloro. Esse sistema permitiu a calibração e a validação do modelo, assim como a avaliação da influência hidráulica na determinação dos resultados de qualidade de água. / The use of chlorine as disinfectant in water supply systems has been a common practice adopted by the water industry. Introduced during the treatment process, chlorine participates in several reactions with compounds of organic and inorganic nature inside the pipes. Such reactions that occur in the bulk and the wall of the pipes are responsible for chlorine decay along the networks. Visualizing the modeling as an efficient tool to manage the chlorine residual in water distribution systems, many studies have been conducted and reported by the literature, assuming that the chlorine decay effects can be well represented by the decay coefficients kb and kw. However, the determination of values for theses parameters is not an easy task, due to the complexity of the focused systems in terms of pipe materials and water supply sources diversity (surface water and groundwater). In Brazil, instead of recent legislation stating more strict limits for chlorine in drinking water (after disinfection, chlorine concentration has to observe the minimum concentration of 0.5 mg/L, being the minimum accepted level in the distribution system of 0.2 mg/L and the maximum of 2.0 mg/L), few studies focus on the evaluation of the decay parameters. This research reports the application of an inverse model built to determine the order for chlorine decay model and the global and/or local values for kb and kw. It is codified with the support of EPANET 2 (Toolkit) simulator and technology of genetic algorithms as optimization tool, which is implemented by using the GAlib C++ library. The studies were conducted on two real water distribution systems considering both global and specific quality parameters. A hypothetical network with three sources of chlorine was studied too, admitting leakage as pressure function. This system permitted both calibration and validation of the model as well as the evaluation of hydraulic calibration influence on the water quality results.

No description available.

A water distribution system (WDS) is based in a network of interconnected hydraulic components to transport the water directly to the customers. Water must be treated in a Water Treatment Plant (WTP) to provide safe drinking water to consumers, free from pathogenic and other undesirable organisms. The disinfection is an important aspect in achieving safe drinking water and preventing the spread of waterborne diseases. Chlorine is the most commonly used disinfectant in conventional water treatment processes because of its low cost, its capacity to deactivate bacteria, and because it ensures residual concentrations in WDS to prevent microbiological contamination. Chlorine residual concentration is affected by a phenomenon known as chlorine decay, which means that chlorine reacts with other components along the system and its concentration decrease. Chlorine is measured at the output of the WTP and also in several considered points within the WDS to control the water quality in the system. Simulation and modeling methods help to predict in an effective way the chlorine concentration in the WDS. The purpose of the thesis is to assess chlorine concentration in some strategic points within the WDS by using the historical measured data of some water quality parameters that influence chlorine decay. Recent investigations of the water quality have shown the need of the use of non-linear modeling for chlorine decay prediction. Chlorine decay in a pipeline is a complex phenomenon so it requires techniques that can provide reliable and efficient representation of the complexity of this behavior. Statistical models based on Artificial Neural Networks (ANN) have been found appropriated for the investigation and solution of problems related with non-linearity in the chlorine decay prediction offering advantages over more conventional modeling techniques. In this sense, this thesis uses a specific neural network application to solve the problem of forecasting the residual chlorine