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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.
1

Sources of human pathogens in urban waters

Younis Hussein, Mariam January 2009 (has links)
<p>The presence of human pathogens in water indicates the sanitary risk associated with different types of water utilization. This study surveyed the sources of human pathogens in urban waters. In order to evaluate the microbiological water quality of urban water, the enumeration of various indicator bacteria (total coliform, fecal coliform, E.coli and enterococci) is usually used.</p><p>The abundance of indicator bacteria in urban water indicates the level of fecal contamination and the presence of other human pathogens such as protozoan pathogens (Giardia lamblia & Cryptosporidium parvum).</p><p>Fecal pollution of urban waters can be from human and animal origin. Point sources of fecal contamination in an urbanized area are the effluents of urban wastewater treatment plants. While non-point sources are usually originated from diffuse sources such as (runoff from roads, parking lots, pets, leaks, failing septic systems and illegal sewer connections to storm drains). urban stormwater is considered as a major carrier for delivering human pathogens from diffuse sources to receiving waters. Increases in urban stormwater volumes have resulted from increasing urbanization and growth of impervious surfaces.</p><p>In order to reduce high amounts of human pathogens in urban waters, different methods are used nowadays to develop urban wastewater treatment plants technologies and urban stormwater management practices.</p>
2

Sources of human pathogens in urban waters

Younis Hussein, Mariam January 2009 (has links)
The presence of human pathogens in water indicates the sanitary risk associated with different types of water utilization. This study surveyed the sources of human pathogens in urban waters. In order to evaluate the microbiological water quality of urban water, the enumeration of various indicator bacteria (total coliform, fecal coliform, E.coli and enterococci) is usually used. The abundance of indicator bacteria in urban water indicates the level of fecal contamination and the presence of other human pathogens such as protozoan pathogens (Giardia lamblia & Cryptosporidium parvum). Fecal pollution of urban waters can be from human and animal origin. Point sources of fecal contamination in an urbanized area are the effluents of urban wastewater treatment plants. While non-point sources are usually originated from diffuse sources such as (runoff from roads, parking lots, pets, leaks, failing septic systems and illegal sewer connections to storm drains). urban stormwater is considered as a major carrier for delivering human pathogens from diffuse sources to receiving waters. Increases in urban stormwater volumes have resulted from increasing urbanization and growth of impervious surfaces. In order to reduce high amounts of human pathogens in urban waters, different methods are used nowadays to develop urban wastewater treatment plants technologies and urban stormwater management practices.
3

The impact of innovative effluent permitting policy on urban wastewater system performance

Meng, Fanlin January 2015 (has links)
This thesis investigates innovative effluent point-source permitting approaches from an integrated urban wastewater system (UWWS) perspective, and demonstrates that three proposed permitting approaches based on optimal operational or control strategies of the wastewater system are effective in delivering multiple and balanced environmental benefits (water quality, GHG emissions) in a cost-efficient manner. Traditional permitting policy and current flexible permitting practices are first reviewed, and opportunities for permitting from an integrated UWWS perspective are identified. An operational strategy-based permitting approach is first developed by a four-step permitting framework. Based on integrated UWWS modelling, operational strategies are optimised with objectives including minimisation of operational cost, variability of treatment efficiency and environmental risk, subject to compliance of environmental water quality standards. As trade-offs exist between the three objectives, the optimal solutions are screened according to the decision-makers’ preference and permits are derived based on the selected solutions. The advantages of this permitting approach over the traditional regulatory method are: a) cost-effectiveness is considered in decision-making, and b) permitting based on operational strategies is more reliable in delivering desirable environmental outcomes. In the studied case, the selected operational strategies achieve over 78% lower environmental risk with at least 7% lower operational cost than the baseline scenario; in comparison, the traditional end-of-pipe limits can lead to expensive solutions with no better environmental water quality. The developed permitting framework facilitates the derivation of sustainable solutions as: a) stakeholders are involved at all points of the decision-making process, so that various impacts of the operation of the UWWS can be considered, and b) multi-objective optimisation algorithm and visual analytics tool are employed to efficiently optimise and select high performance operational solutions. The second proposed permitting approach is based on optimal integrated real time control (RTC) strategies. Permits are developed by a three-step decision-making analysis framework similar to the first approach. An off-line model-based predictive aeration control strategy is investigated for the case study, and further benefits (9% lower environmental risk and 0.6% less cost) are achieved by an optimal RTC strategy exploiting the dynamic assimilation capacity of the environment. A similar permitting approach, but simpler than the first two methods, is developed to derive operational/control strategy-based permits by an integrated cost-risk analysis framework. Less comprehensive modelling and optimisation skills are needed as it couples a dynamic wastewater system model and a stochastic permitting model and uses sensitivity analysis and scenario analysis to optimise operational/control strategies, hence this approach can be a good option to develop risk-based cost-effective permits without intensive resources. Finally, roadmaps for the implementation of the three innovative permitting approaches are discussed. Current performance-based regulations and self-monitoring schemes are used as examples to visualise the new way of permitting. The viability of the proposed methods as alternative regulation approaches are evaluated against the core competencies of modern policy-making.
4

Modelling the performance of an integrated urban wastewater system under future conditions

Astaraie Imani, Maryam January 2012 (has links)
The performance of the Integrated Urban Wastewater Systems (IUWS) including: sewer system, WWTP and river, in both operational control and design, under unavoidable future climate change and urbanisation is a concern for water engineers which still needs to be improved. Additionally, with regard to the recent attention around the world to the environment, the quality of water, as the main component of that, has received significant attention as it can have impacts on health of human life, aquatic life and so on. Hence, the necessity of improving systems performance under the future changes to maintain the quality of water is observed. The research presented in this thesis describes the development of risk-based and non-risk-based models to improve the operational control and design of the IUWS under future climate change and urbanisation aiming to maintain the quality of water in recipients. In this thesis, impacts of climate change and urbanisation on the IUWS performance in terms of the receiving water quality was investigated. In the line with this, different indicators of climate change and urbanisation were selected for evaluation. Also the performance of the IUWS under future climate change and urbanisation was improved by development of a novel non-risk-based operational control and design models aiming to maintain the quality of water in the river to meet the water quality standards in the recipient. This is initiated by applying a scenario-based approach to describe the possible features of future climate change and /or urbanisation. Additionally the performance of the IUWS under future climate change and urbanisation was improved by development of a novel risk-based operational control and design models to reduce the risk of water quality failures to maintain the health of aquatic life. This is initiated by considering the uncertainties involved with the urbanisation parameters considered. The risk concept is applied to estimate the risk of water quality breaches for the aquatic life. Also due to the complexity and time-demanding nature of the IUWS simulation models (which are called about the optimisation process), there is the concern about excessive running times in this study. The novel “MOGA-ANNβ” algorithm was developed for the optimisation process throughout the thesis to speed it up while preserving the accuracy. The meta-model developed was tested and its performance was evaluated. In this study, the results obtained from the impact analysis of the future climate change and urbanisation (on the performance of the IUWS) showed that the future conditions have potential to influence the performance of the IUWS in both quality and quantity of water. In line with this, selecting proper future conditions’ parameters is important for the system impact analysis. Also the observations demonstrated that the system improvement is required under future conditions. In line with this, the results showed that both risk-based and non-risk-based operational control optimisation of the IUWS in isolation is not good enough to cope with the future conditions and therefore the IUWS design optimisation was carried out to improve the system performance. The riskbased design improvement of the IUWS in this study showed a better potential than the non-risk-based design improvement to meet all the water quality criteria considered in this study.
5

Avaluació del paradigma d'agents en la gestió d'un sistema complex d'aigües residuals

Verdaguer Planas, Marta 21 December 2012 (has links)
The thesis presents and evaluates the application of the paradigm of agents to the management of the urban wastewater system. The system is conceptualised as a multi-agent system from the development of the models of agents and communication paths. In the development, it has become obvious that coordination (of volumes and pollutant loads) between all the wastewater treatment inputs and the available capacity of the treatment is a key point in the system’s performance. To consider this factor, a coordinating agent is defined. This agent executes the coordination of inputs and the prioritisation of industrial wastewaters when the treatment does not have sufficient available capacity. The prioritisation is solved by a meta-heuristic of ant colony optimisation, which has been instantiated by four algorithmic versions. Finally, the system has been implemented and consecutive cycles of simulation have been executed with the conclusion that the paradigm of agents is a feasible proposal. / La tesi presenta i avalua l’aplicació del paradigma d’agents en la gestió d’un sistema d’aigües residuals urbanes. El sistema es conceptualitza com a sistema multiagent a partir del desenvolupament dels models d’agents i d’enllaços de comunicació. En el desenvolupament s’evidencia que la coordinació (de volums i càrregues contaminants) entre totes les aportacions d’aigües residuals al tractament i la capacitat disponible d’aquest, constitueix un punt clau del funcionament del sistema. Per tal de considerar-ho, es defineix un agent Coordinador que executa la coordinació de les aportacions al tractament i a més, la priorització dels efluents industrials quan el tractament no disposa de capacitat suficient per admetre totes les propostes d’aportacions. La priorització es resol emprant una metaheurística d’optimització de colònia de formigues, la qual s’instancia mitjançant quatre versions algorísmiques diferents. Per últim, s’implementa el sistema i s’executen cicles consecutius de simulació mostrant com el paradigma constitueix una proposta factible.
6

Amélioration de l’élimination des micropolluants organiques des eaux usées par traitements secondaire et tertiaire / Enhancement of the elimination of organic micropollutants from wastewater at secondary and tertiary stage

Tahar, Alexandre 12 July 2013 (has links)
La présence de micropolluants dans tous les milieux aquatiques est aujourd'hui une préoccupation importante. La réduction des émissions de micropolluants organiques vers le milieu aquatique par les stations d'épuration (STEP) domestiques est donc un enjeu important. Ce travail porte sur l'amélioration du traitement de ces substances par les traitements secondaires et tertiaires des STEP. En premier lieu, l'objectif a été de mieux comprendre les processus d'élimination des micropolluants organiques lors de leur passage au sein d'un procédé de type boues activées aération prolongée (BA-AP). Notre travail a consisté à proposer un outil permettant de prévoir a priori le comportement de substances organiques en BA-AP par rapport à certaines de leurs propriétés physico-chimiques (i.e. constante de Henry, log Dow, structure moléculaire). La démarche adoptée a consisté à sélectionner des données de rendements d'élimination fiables et robustes, puis à les associer aux caractéristiques physico-chimiques des substances. La méthode développée est simple ; elle nécessite de connaitre uniquement des paramètres physico-chimiques facilement accessibles et la structure moléculaire des substances. Elle constitue donc une alternative crédible aux méthodes faisant intervenir la modélisation. Cette méthode permet une prédiction a priori du niveau de traitement d'une substance (rendement supérieur ou inférieur à 70%) par les traitements secondaires existants. Dans un second temps, l'objectif a été de proposer une étape de traitement tertiaire, spécifique à l'élimination de micropolluants organiques réfractaires aux traitements secondaires. Le procédé proposé est une filtration sur support fin spécifique capable de retenir par des processus d'adsorption les substances ciblés (i.e. phytosanitaires et substances pharmaceutiques dont l'élimination est insuffisante en traitement secondaire conventionnel). Une étude bibliographique a permis tout d'abord de dresser un état des lieux sur les adsorbants utilisés et leur capacité d'adsorption. Suite à cette étude, la zéolite et l'argile expansée ont été retenus ; les potentialités d'adsorption de ces deux matériaux ont été étudiées à l'échelle laboratoire (tests en réacteur fermé) et à l'échelle pilote (suivi des performances de réacteurs à garnissage drainé à écoulement horizontal). Les tests d'adsorption en réacteur fermé montrent que les matériaux choisis (argile expansée et zéolite) possèdent une potentialité pour adsorber les substances étudiées (14 substances soient 10 pharmaceutiques et 4 pesticides). Le suivi des réacteurs ouvert confortent les résultats obtenus en réacteur fermé et démontrent que les matériaux étudiés possèdent un potentiel pour l'adsorption des substances ciblées, et ce y compris dans des conditions de filtration lente, proches des conditions réelles. Les résultats obtenus démontrent le potentiel de matériaux minéraux microporeux à éliminer des micropolluants organiques de la phase dissoute et ainsi à se substituer au charbon actif, matériau onéreux et peu adapté aux petites collectivités. / The aim of the present work was to propose solutions to reduce organic micropollutants emissions by wastewater treatment plants (WWTP). First, the objective was to improve the comprehension of micropollutants behaviour in nitrifying activated sludge process. The use of a reliable removal efficiency dataset allowed setting up a removal efficiency prediction method only from the micropollutants physico-chemical characteristics (i.e. log Kow, Henry constant and molecular structure). This method represents a first progress through a better micropollutants removal by the existing secondary WWTP. Second, the aim was to set up a tertiary stage process to enhance the removal of micropollutants refractory to conventional WWTP. This tertiary stage process is a filtration of the secondary effluent by adsorbent materials that could represent a credible alternative to expensive materials such as activated carbons. Experimental approaches at different scales (lab and pilot) demonstrated that some alternative materials such as expanded clay and zeolite have the potential to adsorb refractory substances (e.g. pesticids and pharmaceuticals) and thus to decrease the concentration of organic micropollutants in effluent.
7

Elimination de substances pharmaceutiques d'effluents urbains par un procédé d'oxydation avancée basé sur le radical sulfate / Elimination of pharmaceutical substances from urban wastewater effluent using sulfate radical based advanced oxidation process

Mahdi ahmed, Moussa 15 October 2013 (has links)
Ce travail est consacré à l’étude d’un procédé d’oxydation avancée (POA) basé sur la génération de radicaux sulfates (SO4•-) pour l’élimination de substances pharmaceutiques dans le cadre du traitement d’effluents urbains. Quatre substances pharmaceutiques azotées (carbamazépine, diclofénac, sulfaméthoxazole et ciprofloxacine) appartenant à des familles thérapeutiques différentes ont été choisies en tant que contaminants modèles. L’évaluation de la performance cinétique des procédés basés sur la génération de HO• (H2O2/Fe(II) et UV-C/H2O2) et de SO4•- (HSO5-/Co2+, UV-C/S2O82- et UV-C/HSO5-) a été conduite dans des effluents de stations d'épuration traités biologiquement. La comparaison des procédés non photochimiques et photochimiques a été conduite dans les mêmes conditions optimales et montre que les procédés générant des SO4•- sont moins inhibés par la matrice environnementale que les procédés produisant HO•. La réaction de transfert électronique est mise en évidence par l’identification de produits de transformation des contaminants d’étude par chromatographie liquide couplée à un spectromètre de masse à haute résolution. Le début d’oxydation démarre par un transfert d’un électron sur les groupements azotés générant ainsi un radical cation qui réagit avec l’eau ou l’O2. La dégradation du sulfaméthoxazole est le cas le plus évident grâce à sa fonction amine primaire (aniline) qui se transforme en fonction nitro. On peut par conséquent envisager des nouvelles stratégies de traitement des eaux usées urbaines par la génération de SO4•-. / This work is devoted to the study of an alternative advanced oxidation process (AOP) generating sulfate radical (SO4•-) for the removal of pharmaceuticals in municipal wastewater effluents. Four nitrogen containing pharmaceuticals (carbamazepine, diclofenac, sulfamethoxazole and ciprofloxacin) belonging to different therapeutic classes were chosen as model contaminants. The evaluation of the kinetic performance of processes based on the generation of HO• (H2O2/Fe(II) and UV-C/H2O2 ) and SO4•- (HSO5-/Co2+, UV-C/S2O82- and UV-C/HSO5- ) was conducted in biologically treated effluent. Comparison of photochemical and non- photochemical processes performed under the same optimal conditions showed that the processes generating SO4•- are less inhibited by the environmental matrix than processes producing HO•. This electron transfer reaction is demonstrated by the identification of transformation products using liquid chromatography coupled to high resolution mass spectrometer. Oxidation of parent compounds starts by an electron transfer reaction on the nitrogen groups thereby generating a cation radical which further reacts with water or O2. The sulfamethoxazole degradation pathway gives more insights into this mechanism due to the primary amine moiety (aniline) which is converted into nitro function. This treatment system can be regarded as a new strategy for the treatment of urban wastewater contaminated by pharmaceutical residues through the generation of SO4•-.
8

Sustainable Municipal Water and Wastewater Management Using System Dynamics

Rehan, Rashid 06 November 2014 (has links)
The overall goal of this research is to develop an integrated system dynamics framework for sustainable management of municipal water and wastewater systems. Canadian municipalities have traditionally relied on grants received from senior levels of government to finance construction of water supply and wastewater collection infrastructure. User fees for water and wastewater services were determined so as to recover only the operating expenditures with no allowance to recoup the capital costs of infrastructure. As the infrastructure assets started approaching the end of their service life, investments needed to rehabilitate these assets were deferred in the expectation of receiving further grants for this purpose. Hence, a significant backlog of deteriorated infrastructure has accumulated over the years. Recently enacted regulations require that all expenditures incurred on provision of water and wastewater services should ultimately be financed from user fee based revenues. Another piece of legislation provides for establishment of service performance standards. Urban water and wastewater systems involve interconnections among physical infrastructure, financial, and socio-political factors. Several interacting feedback loops are formed due to these interconnections and render the management of water and wastewater infrastructure as a complex, dynamic problem. Existing asset management tools in the literature are found inadequate to capture the influence of feedback loops. A novel system dynamics approach is used to develop a demonstration model for water and wastewater network management. Model results for a case study show significance of feedback loops for financial sustainability of the system. For example, user fees have to be substantially increased to achieve financial sustainability, especially when price elasticity of water demand is considered. A detailed causal loop diagram for management of wastewater collection networks is presented. The causal loop diagram lays out qualitative causal relationships among system components and identifies multiple interacting feedback loops. Based on this causal loop diagram, a system dynamics model comprised of a wastewater pipes sector, a finance sector, and a consumers sector, is developed. Policy levers are included in the model to facilitate formulation of different financing and rehabilitation strategies for the wastewater collection network. Financial and service performance indicators included in the model allow comparison of different financing and rehabilitation strategies. Data requirements for implementation of the model are discussed. The wastewater collection network model is implemented for a case study of a medium-sized Canadian municipality with a substantial backlog of deteriorated pipes. A methodology for parameterization of the model using existing data sources is presented. Simulation results indicate that different financing strategies ranging from no borrowing to full utilization of debt capacity can achieve similar total life-cycle costs but with significantly varying impacts for consumers in terms of service performance and financial burden. A detailed causal loop diagram for management of a watermain distribution network is employed to identify feedback loops. The causal loop diagram is then developed into a system dynamics model comprised of watermain pipes, financial, and consumer sectors. Data requirements for implementation of the model are discussed.
9

Estudo da aplicação de processos oxidativos avançados no tratamento de águas pluviais do Riacho das Águas Férreas – Maceió, AL / Study of application of advanced oxidative processes in stormwater treatment of Águas Férreas Creek – Maceió, AL

Araújo, Jenivaldo Lisboa de 30 August 2018 (has links)
The presDue to the system does not recognize equations and formulas the resumo and abstract can be found in the PDF file. / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Devido ao sistema não reconhecer equações e fórmulas o resumo e abstract encontra-se no arquivo em PDF.
10

Mise au point de techniques de traitement de données en continu pour l’identification des composantes de débit à l’exutoire des bassins versants urbains : étude de cas des bassins versants Django Rheinhardt et Ecully / Development of processing techniques for continuous data to identify flow components at the outlet of urban catchments : case study of Django Reinhardt and Ecully watershed

Dorval, Farah Altagracia 20 June 2011 (has links)
L’objectif de cette thèse est de développer, tester et valider des méthodes, techniques et outils permettant de traiter et décomposer les hydrogrammes en temps sec et en temps de pluie, dans le but de comprendre, de représenter et de prédire les dynamiques liées à ces composantes de débits sur des bassins versants urbanisés. Les données en continu de temps sec recueillies sur ces deux bassins versants Chassieu et Ecully ont été traitées à partir de la méthode de traitement des signaux bruités par ondelettes, puis analysées. L’utilisation de ces méthodes et l’analyse des données en continu a permis de mettre en évidence des composantes périodiques intra et inter journalières dans les débits mesurés. Ces composantes ont ensuite été caractérisées puis ont servi de base pour l’élaboration d’une typologie des hydrogrammes de temps sec relatif à chaque site d’étude. Des méthodes, techniques et outils de traitement, d’analyse de séries de données et de calage de modèles pluie-débit ont également été utilisés et deux modèles pluie-débit ont été proposés pour représenter : (i.) la composante liée aux eaux de ruissellement pour les deux sites d’études et (ii.) la composante d’eaux parasites d’infiltration événementielle. La typologie des hydrogrammes de temps sec ainsi que les modèles de production de flux d’eaux en périodes pluvieuses ont été implémentés dans une plate-forme de modélisation hydrologique appelée « Hydrobox ». Les débits simulés ont ensuite été confrontés aux débits mesurés. Les résultats de comparaison montrent l’intérêt de prendre en compte la signature particulière portée par chaque composante dans le but d’améliorer la compréhension et la représentation des dynamiques liées aux processus hydrologiques intervenant sur des bassins versants urbanisés. / The objective of this thesis is to develop, test and validate methods, techniques and tools which can process and decompose hydrographs in order to understand, represent and predict the dynamics associated with these flow components in urbanized watersheds. The development of the methodology is based on rainfall and runoff data including qualitatives measures of the flow rate (conductivity, pH and turbidity) continuously acquired as part of the Field Observatory for Urban Hydrology (OTHU) for two watersheds in Lyon: Django Reinhardt (Chassieu) and Ecully. The continuous data collected in dry weather period from these two watersheds were analyzed using wavelets transforms. These methods combined to signal treatments analysis helped to reveal periodic component in the measured flows. These components were then characterized and used as a basis for developing a typology of hydrographs of dry weather period for each study site. Methods, techniques and tools for processing and analyzing of data sets and calibrating of rainfall-runoff models have been used to propose two models which represent respectively: (i) the component related to the runoff contribution for the two study sites and (ii.) the component related to parasitic water infiltration. The typology of hydrographs for dry weather period, the rainfall-runoff model and the infiltration-inflow model were implemented in a platform for hydrological modeling called “Hydrobox”. The simulated and the measured flow values were then compared. The comparison results show the importance of taking into account the particular signature carried by each component in order to improve the understanding and representing the dynamics related to hydrological processes in urbanized watersheds.

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