This thesis is broken into two parts. The first part, Chapters 1 - 7, focuses on work completed performing partial performance assessments in two case studies: the region of Peel in the Greater Toronto Area, and Tláhuac, Mexico. In both, pressure transients were monitored using high-speed sensors. The second part, Chapters 8 - 10, proposes a framework for performance assessments of water transmission and distribution systems, primarily applicable to analysis and operation yet useful in (re)design or additional design work as well. The framework is a synthesis of concepts ranging from fuzzy engineering to psychology and human factors, and will be of particular interest to larger, more sophisticated water utilities who may have a general understanding of their systems but lack specific insights in its operation and operational effectiveness. Careful consideration is given to not only the type of information and possible information fusion, but also details of necessary software and hardware, including possibilities for the system architecture.

This thesis is broken into two parts. The first part, Chapters 1 - 7, focuses on work completed performing partial performance assessments in two case studies: the region of Peel in the Greater Toronto Area, and Tláhuac, Mexico. In both, pressure transients were monitored using high-speed sensors. The second part, Chapters 8 - 10, proposes a framework for performance assessments of water transmission and distribution systems, primarily applicable to analysis and operation yet useful in (re)design or additional design work as well. The framework is a synthesis of concepts ranging from fuzzy engineering to psychology and human factors, and will be of particular interest to larger, more sophisticated water utilities who may have a general understanding of their systems but lack specific insights in its operation and operational effectiveness. Careful consideration is given to not only the type of information and possible information fusion, but also details of necessary software and hardware, including possibilities for the system architecture.

Drinking water distribution systems (WDSs) hold a particularly critical and strategic position in preserving public health and industrial growth. Despite the ubiquity of this infrastructure, its importance for public health, and increased risk of terrorism, several aspects of emergency management for WDSs remain at an undeveloped stage. A set of methods is developed to analyze the risk and consequences of WDS contamination events and develop emergency response support tools. Monte Carlo and optimization schemes are developed to evaluate contamination risk of WDSs for generation of critical contamination scenarios. A multicriteria optimization approach is proposed that treats likelihood and consequences as independent risk measures to find an ensemble of uniformly-distributed critical scenarios. This approach provides insight into system risk and potential mitigation options not available under maximum risk or maximum consequences analyses. Static multiobjective simulation-optimization schemes are developed for generation of optimal response mechanisms for contamination incidents with twoconflicting objectives of minimization of health consequences and impacts on non-consumptive water uses. Performance of contaminant flushing and containment are investigated. Pressure-driven hydraulic analysis is performed to simulate the complicated system hydraulics under pressure-deficit conditions. Performance of a novel preventive response action ? injection of food-grade dye directly into drinking water ? for mitigation of health impacts as a contamination threat unfolds is explored. The emergency response is formulated as a multiobjective optimization problem for the minimization of risks to life with minimum false warning and cost. A multiobjective optimization scheme is used for the management of contamination events for diverse contaminant agents without interruption of firefighting. A dynamic modeling scheme is developed that accounts for the time-varying behavior of the system during an emergency. Effects of actions taken by the managers and consumers as well as the changing perceived contaminant source attributes are included in the simulation model to provide a realistic picture of the dynamic environment. A dynamic optimization scheme is coupled with the simulation model to identify and update the optimal response recommendations during the emergency. Machine learning approaches are employed for real-time characterization of contaminant sources and identification of effective response strategies for a timely and effective response to contamination incidents and threats. In contrast to traditional approaches that perform whole analysis after a contamination event occurs, proposed machine learning methods gain system knowledge in advance and use this extracted information to identify contamination attributes after an incident occurs.

The formation of an objectionable "swampy" odour in drinking water distribution systems in Perth, Western Australia, was first described by Wajon and co-authors in the mid-1980s (Wajon et al., 1985; Wajon et al., 1986; Wajon et al, 1988). These authors established that the odour, variously described as "swampy", "sewage" or "cooked vegetable" was caused by dimethyltrisulfide (DMTS) which has an odour threshold concentration of 10 nanograms per litre (ng/L). Investigations described in the present Thesis extend the work of Wajon and co-workers in attempting to establish the origin and cause of DMTS formation in Perth drinking water distribution systems.The DMTS problem appeared to be confined to water originating from a particular type of groundwater, specifically groundwater sourced from shallow, unconfined aquifers, which contain relatively high concentrations of sulfide, dissolved natural organic matter (NOM) and dissolved iron. DMTS was not present in the groundwater, but only formed in the distribution system, after treatment of groundwater via alum coagulation-filtration and oxidation processes. One objective of the present work was to determine the reasons for the observed association between DMTS formation and this specific groundwater type. A primary focus was to investigate the chemistry and biochemistry of sulfur species and NOM which might act as precursors to DMTS. The work was driven by the view that increased understanding of the problem might lead to more effective and acceptable treatment solutions than those presently in use.The observation that DMTS forms in distributed water that originates from groundwater, but not in water from surface sources has led to the hypothesis that groundwater NOM may contain precursor(s) to DMTS For example, it was proposed that methyl esters and ethers within humic substances might be a source of methyl groups that ++ / could participate in DMTS formation in distributed water (Wajon and Heitz, 1995; Wajon and Wilmot, 1992). Further, comparison of levels of reduced sulfur with levels of dissolved organic carbon (DOC) in groundwaters feeding Wanneroo GWTP revealed that a positive correlation between these two parameters existed. This observation provided further impetus to examine the nature of NOM in these groundwater systems. In the present study (discussed in Chapter 3), NOM from two Perth drinking water sources was isolated and characterised, with the aim of identifying major differences in structure and/or functional groups that might influence DMTS formation. NOM was isolated from water samples using ultrafiltration, and characterised using pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) and offline- thermochemolysis/methylation (TCM). Pyrolysis of groundwater NOM yielded a high proportion of organosulfur compounds, primarily methyl thiophenes and sulfur gases, but did not yield detectable amounts of methoxy-aromatic compounds. Analysis by TCM yielded sulfur compounds tentatively identified as the methyl esters of methylthiopropanoate and methylthiobutanoate, compounds that may arise as degradation products of dimethylsulfoniopropionate (DMSP), an algal odmoregulator Compounds such as DMPS could potentially undergo reactions to form DMTS in distributed water.The task of investigating the formation of nanogram-per-litre concentrations of DMTS demanded the development of new analytical procedures that could be used to determine similarly low concentrations of DMTS precursors. Evidence existed to suggest that inorganic polysulfides could be plausible precursor compounds, and since no technique existed to analyse and quantify individual polysulfide homologues a new technique needed to be developed and verified. The technique, first used in a semiquantitative manner by ++ / Wajon and Heitz (1995), utilizes methyl iodide to derivatise polysulfides in-situ. The technique was developed further and shown to be quantitative and specific for inorganic polysulfides. Further, a new procedure for the determination of d i methyl polysulfides (DMPSs; CH3SnCH3, where n = 2-5), based on purge and trap was developed. In this new procedure analytes were trapped on a "Grob" activated charcoal tube, which was integrated into a commercially available, automated purge and trap instrument. Perdeuterated analogues of the DMPS analytes were synthesized and used as internal standards. These modifications resulted in a more rapid and robust procedure than the previously used procedures, vii which were based on closed loop stripping analysis (CLSA). Validation of the precision, accuracy, linearity and robustness of the new procedures for both inorganic polysulfides and dimethylpolysulfides is described in Chapter 4.Previous authors (Wajon and Heitz, 1995; Wajon and Wilmot, 1992; Wilmot and Wajon, 1997) hypothesized that DMTS could arise in the distribution system from residual polysulfides or other reduced sulfur compounds originating from groundwater. The latter authors showed that a small proportion of sulfide in the groundwater was not completely oxidised to sulfate during the water treatment process and proposed that this residual reduced sulfur fraction, which they referred to as non-sulfide reduced sulfur (NSRS) could contain precursors to DMTS. In a review of the chemistry of sulfide oxidation (Chapter 2) it was shown that the most likely forms of sulfur comprising the NSRS that enters the Wanneroo distribution system are organosulfur compounds and elemental sulfur, probably associated with organic matter in the form of a sulfur sol.Analysis of inorganic polysulfides in treated water, using the newly described method in Chapter 4, revealed that small ++ / amounts of these compounds (20-80 ng/L) were occasionally present in some samples. However, it was concluded that, since inorganic polysulfides could not survive water treatment processes, these compounds probably arose from traces of biofilm or pipe sediment that may have entered the water during sampling. It was proposed that the presence of biofilm particulates in water samples probably also accounted for observations that DMTS appeared to form in some water samples during storage of the sample. These studies are discussed in Chapter 5.The primary method of control of DMTS formation in the distribution system has been to maintain free chlorine residuals. However, the mechanisms by which this occurs have not been studied; the effectiveness of DMTS oxidation by chlorine, or how chlorine affects microbial processes that might form DMTS is not known. These issues are addressed in the final section of Chapter 5. Experiments to determine the effectiveness of oxidation of dimethyldisulfide (DMDS) and DIVITS (5 mu g/L) by free chlorine (0.2 to 0.6 mg/L) in distributed water showed that these substances are rapidly and completely oxidised in water containing a chlorine residual of more than 0.4 mg/L. However, slow regeneration of traces of DMDS and DIVITS after dissipation of free chlorine to non-detectable levels showed that these compounds were incompletely oxidised at the lower chlorine concentrations~ This provides some rationale for field observations that DIVITS occurs even where low, but measurable, chlorine residuals appear to exist (<0.2 mg/L).As was established in a review of the chemistry of reduced sulfur compounds Chapter 2), reducing conditions not present in the oxic bulk water are required for DMTS to form and to persist. It was therefore proposed that microbial reduction processes could generate anoxic microniches in the distribution system, within which ++ / DMTS production could occur. This hypothesis was investigated in Chapter 6; the new methods for analysis of organic and inorganic polysulfides were applied to the study of biofilms and deposits of colloidal material found in distribution pipes and storage reservoirs. The study demonstrated that these materials contained concentrations of methylated and inorganic polysulfides four to six orders of magnitude higher than those ever found in the bulk water phase. The results indicated that reducing conditions most probably exist within the biofilms and pipewall deposits, where these polysulfides were formed. The iron-rich pipe slimes appeared to protect the sulfur compounds against the oxidative effects of chlorine and dissolved oxygen. It was concluded that the organic and inorganic polysulfides most probably arise through microbial sulfate reduction processes that occur in anoxic microenvironments within the slimes and deposits.Microbial processes that lead to the formation of polysulfides and dimethylpolysuifides under conditions approximately representative of those in distribution systems were investigated in work described in Chapter 7. The aim of this work was to investigate the role of biofilms in the formation of DMTS and to determine the nature of chemical precursors which might stimulate these processes. Biofilms, artificially generated on synthetic supports within chambers filled with water from Wanneroo GWTP, were exposed to compounds thought to be potential DMTS precursors. The response of the systems in terms of production of methylated sulfur compounds was monitored. Conclusions of the study were that, under the test conditions, production of DMDS and DMTS could occur via several mechanisms and that these dimethyloligosulfides could be formed even without the addition of compounds containing sulfur or methyl moieties. DMTS did not form in the absence of ++ / biofilms and it was therefore concluded that minimisation of biofilm activity was a key in preventing DMTS formation. Outcomes of the work imply that environments within distribution systems are complex and dynamic, as perhaps manifested by the intermittent nature of the DMTS problem.Finally, in Chapter 8 the conclusions to the present studies are summarised. It is shown how they underpin the rationale for proposed new treatment solutions aimed at preventing DMTS problems in the Wanneroo zone, primarily by minimising microbial activity and biofilm formation within distribution systems.

Thesis (MTech (Technology))--Cape Peninsula University of Technology, 2005 / Potable water, and especially the accessibility to it, is an essential part of everyday life. Of particular note, is the challenge that residents of remote rural African villages face in order to gain access to this basic requirement. Specifically, the rural areas in the Northern Cape (Province north of Cape Town) region in South Africa is one such example that illustrates this problem very well. In order to address the requirements for drinkable water, various types of water pumping technologies have been used. Up to now, the two competing water pumping systems, diesel and photovoltaic (PV), have been the primary technologies deployed in selected sites in the Northern Cape. The manual data collection of water pumping system data in the Northern Cape is fraught with impracticalities such as travel costs and requirements for skilled personnel. Therefore, as a preliminary step to accelerate development and testing, a local experimental laboratory PV water pumping rig was set-up within the Department of Mechanical Engineering at the Cape University of Technology. A short-term analysis was performed over a period of three weeks on the rig and the experimental results indicated the following: array efficiency of 16.3%, system efficiency of 15.0% and an average system efficiency of 1.47%. However, the results do indicate that long-term monitoring of PV water pumping systems can be suitable in serving to determine dynamic system performance and system life cycle costs. The purpose of this project is two-fold - firstly, to present the results on the work done on the experimental PV system.

O presente trabalho tem por objetivo apresentar o efeito da redução de pressões nas redes de distribuição sob as perdas reais de água. Para desenvolvimento do trabalho foram recolhidos dados de campo que permitiram avaliar as condições dos sistemas de distribuição e montar modelos matemáticos para realização de simulações hidráulicas. A partir dos modelos, se desenvolveram os estudos de caso para o Setor de Abastecimento de Ermelino Matarazzo (no município de São Paulo) e para o Setor Fonte (em Araraquara). No caso do Setor Ermelino, efetivamente implantaram-se subsetores controlados por válvulas redutoras de pressão (VRPs), obtendo-se reduções significativas na vazão fornecida à distribuição. Para o Setor Fonte, foram realizados estudos para reformulação da setorização existente e subdivisão em Distritos de Medição e Controle (DMCs) levando-se em conta todas as obras para melhoria e adequação do sistema de distribuição. A subsetorização proposta para o Setor Fonte não foi efetivamente implantada, mas os modelos desenvolvidos mostraram que apenas com a subdivisão do setor já é possível a redução nas pressões de distribuição e conseqüentemente redução das perdas reais. Para o Setor Ermelino optou-se pela solução com resultados imediatos através da instalação das válvulas: as perdas reais foram reduzidas, embora tenha significado que 80% da extensão de rede da zona alta do setor tenha ficado protegida por VRPs, o que sugere um desperdício de energia. Já no Setor Fonte buscou-se uma solução mais abrangente para otimização do sistema de distribuição e equilíbrio hidráulico do plano piezométrico, que também apresenta resultados satisfatórios na redução das perdas reais de água. Finalmente, concluiu-se, através dos resultados obtidos em ambos os estudos que a redução das pressões na distribuição está intimamente ligada à redução das perdas reais de água. A diferença entre eles é a abrangência dos estudos. É desejável que o imediatismo dos resultados obtidos pela instalação das VRPs seja confrontado com ações de longo prazo e que a utilização de VRPs seja acessória ao sistema de distribuição e não usada indiscriminadamente. / The following study aims to present the effect of pressure reducing in the distribution networks over the water real loss. For development of the studies, were collected field data that allowed to evaluate the distribution systems conditions and build mathematical models for hydraulic simulations. From the hydraulics models, were developed cases for the Water Supply Ermelino Matarazzo District (in São Paulo) and the Fonte District (in Araraquara). In the Ermelino Districts case, in fact were deployed pressure reducing valves (PRVs) sub-districts, resulting in significant reductions in the supplied flow to the distribution system. For the Fonte District, studies were developed to reformulate the existing sectorization and the subdivision into District Meter Areas (DMAs) taking into account all the activities for improvement and adjustment of the distribution system. The proposal to subdivide the Fonte District had not been effectively implemented, but the models developed showed that only the sub-sector division is enough to reduce the pressure distribution and therefore reduce real losses. For Ermelino District was chosen the solution with immediate results through the installation of the valves: the actual losses have been reduced, meaning that although 80% of the network extension of the High Service Area has been protected by PRVs, which suggests an energy waste. In the Fonte District sought an embracing solution for the distribution system optimizing and gain the best hydraulic balance of the piezometric plan, that also provides satisfactory results in the reduction of real losses. Finally, it was concluded through the results obtained in both studies that, the pressure reduction in distribution system is closely linked to the real losses reduction. The difference between them is the scope of the studies. It is desirable that the immediate results achieved by the PRVs installation be compared with long-term actions and, the use of PRVs should be an accessory to the distribution system and not used indiscriminately.

Orientador: Paulo Vatavuk / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-26T16:05:38Z (GMT). No. of bitstreams: 1 Costa_EdsonSeneda_M.pdf: 9039767 bytes, checksum: e9d0b4f243d44d427133eff873f18844 (MD5) Previous issue date: 2014 / Resumo: O problema de perdas de água em redes de abastecimento é um dos principais desafios dos gestores dos sistemas. Neste trabalho pretende-se avaliar um caso prático no qual a alteração do ponto de alimentação da rede de água possibilitou redução de perda de água devido à diminuição das pressões na área estudada. A região central do município de Cotia abastecido pelo setor Cotia-Jardim Atalaia, tinha o ponto de alimentação da rede situado em um local distante de seu ponto crítico alto. Devido ao crescimento populacional, este reservatório ficou com a demanda de água maior que a oferta, e, houve a necessidade de realizar a diminuição de sua área de atuação. Para resolver a questão, a área de estudo foi retirada do setor Cotia-Atalaia e passou a ser abastecida pelo setor Cotia-Centro que suportou o acréscimo de vazão. Com essa mudança, o novo ponto de alimentação da região central coincidiu com o ponto crítico alto e houve uma redução das perdas no período diurno. Durante a investigação do ocorrido, mediante modelagem matemática e medições de vazão e pressão em campo, ficou demonstrado que, em um Distrito de Medição e Controle (DMC), quando se tem um único ponto de alimentação e que seja pelo ponto crítico alto, há uma redução das pressões diurnas e, consequentemente, diminuem as taxas de vazamentos / Abstract: The problem of water loss in distribution systems is one of the main challenges faced by the system managers. The purpose of this work is to evaluate a practical case in which the change of the feed point of the network enabled a reduction of water loss due to the reduction of pressures in the studied area. The central region of the city of Cotia, supplied by the Cotia-Jardim Atalaia sector, had the main supply point located far from the critical (high elevation) point. Due to population growth, this tank had its water demand exceeded, and then the need for the reduction of its operating area appeared. To solve the issue, the study area was removed from Cotia-Jardim Atalaia sector and is now supplied by Cotia-Centro sector that accepted the flow increase. With this change, the new feed point of the central region matched the critical high point and there was a reduction in losses during the day. During the investigation of the incident by mathematical modeling and field flow and pressure measurements, it was shown that, in a District Metered Areas (DMA), when you have a single point of supply that matches the critical high point, there is a reduction in daytime pressures and thus a reduction of leakage rates / Mestrado / Recursos Hidricos, Energeticos e Ambientais / Mestre em Engenharia Civil

This study compared four different water main failure prediction models: a statistically simple model, a statistically complex model, a statistically complex model with modifications termed the 2019 model, and an age-based model. The statistically complex models compute the probability of failure based on age, size, internal pressure, length of pipe in corrosive soil, land use, and material of the. These two values are then used to prioritize a water main rehabilitation program to effectively use the municipality’s funds. The 2019 model calculates the probability of failure and consequence of failure differently than the statistically complex model by considering corrosive soil data instead of assuming all the pipes are in highly corrosive soil and average daily traffic volume data instead of using street classifications. The statistically simple model only uses the pipe age and material for probability of failure. The age-based model relies purely on the age of the pipe to determine its probability of failure. Consequences of failure are determined by the proximity of the pipe to highly trafficked streets, critical services, pipe replacement cost, and the flow capacity of the pipe. Risk of failure score is the product of the consequence of failure score and probability of failure score. Pipes are then ranked based on risk of failure scores to allow municipalities to determine their pipe rehabilitation schedule. The results showed that the statistically complex models were preferred because results varied between all four models. The 2019 model is preferred for long-term analysis because it can better account for future traffic growth using the average daily traffic volume. Corrosive soil data did not have a significant impact on the results, which can be attributed to the relatively small regression parameter for corrosive soil. The age-based model is not recommended because results of this study shows it places a significantly high number of pipes in the high and critical risk categories compared to the other models that account for more factors. This could result in the unnecessary replacement of pipes leading to an inefficient allocation of funds. Keywords: Risk of Failure, Consequence of Failure, Probability of Failure

Pipes in water distribution systems may change as they age. The accumulation of corrosion byproducts and suspended particles on the inside wall of aged pipes can increase pipe roughness and reduce pipe diameter. To quantify the hydraulic effects of irregular accumulation on the pipe walls, eleven aged pipes ranging in diameter from 0.020-m (0.75-in) to 0.100-m (4-in) and with varying degrees of turberculation were located and subjected to laboratory testing. The laboratory test results were used to determine a relationship between pipe diameter reduction and Hazen-Williams C. This relationship, combined with a manipulation of the Hazen-Williams equation, provided a simple and direct method for correcting the diameters of aged pipes in distribution models. Using EPANET 2, the importance of correcting pipe diameters when modeling water distribution systems containing aged pipes was investigated. Correcting the pipe diameters in the sample network reduced the modeled water age by up to 10% and changed the pattern of fluctuating water age that occurred as waters with different sources moved through the pipe network. In addition, two of the aforementioned aged pipes with diameters of 0.025-m (1-in) and 0.050-m (2-in) were modeled using Reynolds-Averaged Navier-Stokes (RANS) turbulence modeling. Flow was computed at Reynolds numbers ranging from 6700 to 31,000 using three turbulence models including a 4-equation v2-f model, and 2-equation realizable k-e; and k-ω models. In comparing the RANS results to the laboratory testing, the v2-f model was found to be most accurate, producing Darcy-Weisbach friction factors from 5% higher to 15% lower than laboratory-obtained values. The capability of RANS modeling to provide a detailed characterization of the flow in aged pipes was demonstrated. Large eddy simulation (LES) was also performed on a single 0.050-m (2-in) pipe at a Reynolds number of 6800. The Darcy-Weisbach friction factor calculated using LES was 20% less than obtained from experimental tests. Roughness elements smaller than the grid scale and deficiencies in the subgrid-scale model at modeling the complex three-dimensional flow structures due to the irregular pipe boundary were identified as likely sources of error. Even so, the utility of LES for describing complex flows was established.

No description available.