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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.
291

Advective water quality model for urban watercourses.

Furumele, Musa Stefane January 1991 (has links)
A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineerrng, / As has happened throughout the world. environmental and water quality problems related to developing urban and industrial areas and associated accumulation of waste in built-up areas were the main factors in contributing to sanitary awareness in South Africa. The dwindling water resources and persistent deterioration of water quality, more severely in urban areas, necessitates the review the current practice of storm water management in South Africa. Reliable stormwater drainage models evaluating both the water quantity and quality could be essential in confronting the prevailing pollution problems. The objective of this project was conceived to be the development of a system for the simulation of water quality in urban watercourses, A personal computer compatible model for joint transportation of hydrograph and pollutographs in open channels was developed. The model comprises an operational data handling facility, a user friendly and interactive interface. The study revealed that: Urban and Industrial development results in complication of the urban water system. • Single objectivity approaches in management of urban watercourses are outdated . .. The proposed model is capable of simultaneously routing flood and pollutant condiment waves in open channels. Understanding of aspects of the water quality in urban watercourse can be greatly enhanced by the proposed model. The following recommendations were henceforth made: • Detailed study of the nature. quantity and sources of pollutants in the urban water system. .. Sophisticated (dynamic wave. supercritical flow, complicated ..................... hydrodynamic model snould be considered, • Biological and, chemical process in the urban watercourse be incorporated. • Linking of the water quality model to the storm water drainage model, / Andrew Chakane 2018
292

Técnica de gerenciamento da qualidade hídrica superficial baseada na otimização multiobjetivo / A technic of surface water quality management based on the multiobjective optimization

Albertin, Liliane Lazzari 09 May 2008 (has links)
Os problemas de gerenciamento da qualidade da água envolvem diversas aspirações dos usuários envolvidos, quer sejam eles os que usam o recurso hídrico para diluição de seus efluentes ou para seu consumo. Portanto, é raro que os modelos matemáticos usados para auxílio nas tomadas de decisões sejam expressos em termos de um único objetivo, como a maximização da eficiência econômica. Para o aproveitamento de um determinado sistema hídrico, deve ser considerada a distribuição eqüitativa, o uso racional, a maximização da eficiência econômica, a minimização dos impactos ambientais, entre outros. Neste contexto, três modelos de otimização multiobjetivo foram propostos e foram considerados a maximização da carga lançada pelas fontes poluidoras, a melhora qualitativa da água, e a minimização da magnitude das violações dos padrões de qualidade da água. A principal contribuição deste trabalho está na incorporação de uma restrição ao modelo de otimização multiobjetivo. A restrição proposta representa um índice que tem o intuito de distribuir eqüitativamente a eficiência do tratamento necessária entre as fontes de poluição. Sem a consideração de uma medida de eqüidade, a tentativa de maximizar a quantidade de efluentes lançados resultaria numa alocação de grandes quantidades de efluentes passíveis de serem lançados pelos usuários localizados mais a montante do rio, enquanto que os usuários à jusante deveriam tratar seus efluentes com um nível máximo de eficiência. O método utilizado para solucionar o problema foi o non-dominated sorting genetic algorithm e este estudo teve sua aplicação na bacia do rio Atibaia, SP. As soluções apresentadas pela otimização demonstram e comprovam os conflitos existentes e a competição entre os critérios considerados. O algoritmo genético demonstrou ser uma técnica efetiva para solucionar problemas de otimização multiobjetivo em aplicações de gerenciamento da qualidade da água, identificando as variáveis de decisão e a frente Pareto. / Problems of water quality management involve many aspirations of the users engaged, those that use water for wastewater dilution or for their consumption. Therefore, it is uncommon that decision-making mathematical models used are expressed in terms of a single objective, like the maximization of economic efficiency. Using a particular water system, one should consider the equitable distribution, the rational use, the maximization of economic efficiency, the minimization of environmental impacts, among others parameters. In this context, three models of multiobjective optimization were proposed and considered to maximize the wastewater discharge by point sources, the qualitative improvement of the water, minimizing the magnitude of the violations of water quality standards. The main contribution of this work was the incorporation of a restriction on the multiobjective optimization model. The proposed restriction is an index that intends to distribute equitably the efficiency of treatment needed between pollution sources. Without considering equity measure, the attempt to maximize waste discharge would result in an allocation of large quantities of waste to the upstream users, while the downstream dischargers would be required to treat their effluents at levels of maximum possible efficiency. The method used to solve the problem was the non-dominated sorting genetic algorithm (NSGA) and the case study was implemented in the Atibaia river basin, SP. The solutions presented by the optimization show and prove the existing conflicts and competition among the criteria considered. The genetic algorithm has been shown to be an effective technique for solving problems of multiobjective optimization in applications of water quality management, identifying the decision variables in Pareto front.
293

Effect of Electronic Water Treatment System on Calcium Carbonate Scaling

Unknown Date (has links)
Calcium carbonate precipitation and formation of clog particles inside the leachate collection pipe can cause catastrophic failures in landfill operation. This study focuses on quantifying the effectiveness of electronic scale control to reduce the clog formation within the pipe network. A field scale model (40ft × 20ft) was constructed, featuring side-by-side flow of electronically treated and untreated composite leachate. Data obtained in the first phase of this study indicate that electronic scale control system does not have any statistically significant effect on water quality parameters. The second phase of this study identified calcite (CaCO3) to be the predominant phase present in the precipitates using XRD/XRF diffraction pattern analyzed through a search match calculation program (MATCH! Version 3.2.0) which concur with the previous studies. Furthermore, Rietveld refinement using FullProf Suite confirms that there were no differences between the treated and untreated precipitate based on the phases identified in the respective samples. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
294

A lime softening system for individual-household use powered by solar energy

Unknown Date (has links)
A study conducted by the World Health Organization and United Nations Children's Fund, concluded that approximately 768 million people worldwide are not receiving sanitary drinking water suitable for consumption. While there are many water treatment methods, lime softening proves to be one of the more effective approaches as it removes a wide variety of harmful compounds including arsenic, lead, mercury, and cadmium under the correct conditions. The greatest issues with lime softening on a smaller scale include the complexity of the chemistry and need for monitoring. By designing the system for groundwater sources and with a smaller capacity, this thesis hoped to reduce the level of monitoring, chemical expertise, and cost needed for operation. While promising results occurred in the removal of arsenic and total hardness, this project was unable to obtain consistent results and final water samples with pH values between the recommended standard of 6.5 to 8. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection
295

The correlations between OSTDS sites and the pollution of the surface water bodies in Broward County

Unknown Date (has links)
Sampling data of many surface water bodies in Broward County tend to reveal abnormal levels of bacterial concentrations for total coliform, Escherichia coli and Enterococcus. Given the presence of septic systems in geohydrologically sensitive areas throughout the County, several studies (Morin 2005 and Bocca 2007) suggested a correlation in the high bacterial densities and the septic sites. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
296

Hydrodynamic and Water Quality Modeling of the Tigris River System in Iraq Using CE-QUAL-W2

Al Murib, Muhanned 21 March 2018 (has links)
The Tigris River is one of two primary rivers in Iraq and is, along with the Euphrates, the main source for drinking and irrigation water in the country. The Tigris River originates in the Taurus Mountains in Turkey, and is 1850 km long. The majority of the river lies within Iraq. The river passes through, and is the primary drinking water source for major cities such as Mosul, Baeji, Samarra, Baghdad (the capital), and Kut. The Tigris River joins the Euphrates River in Qurna city within Basra province to form the Shatt Al-Arab River which eventually discharges into the Persian Gulf. As a result of fluctuations in flow rate along the Tigris River that cause both potential flooding and drought, Mosul Dam was built on the mainstem of the Tigris River upstream of the city of Mosul and was operated starting in July 1986 to control the river flow and to generate hydroelectricity. Some canals were also constructed to divert excess fresh water from the mainstem of the river at Samarra Barrage located 125 km north (upstream) of Baghdad to Tharthar Lake, an artificial lake located 100 km northwest Baghdad city. The Tigris-Tharthar canal, 75 km long, was constructed in 1956 to divert excess water from Samarra Barrage to Tharthar Lake and to prevent potential flooding in Baghdad. During dry seasons, high total dissolved solids (TDS) water is diverted from Tharthar Lake into the mainstem of the Tigris River through the 65 km long Tharthar-Tigris canal, which is located 25 km upstream Baghdad. Due to rapid population growth and increasing industrial activates, the Tigris River is also facing many water quality challenges from inflows of contaminated wastewater from treatment plant stations. A water quality model that simulates the Tigris River system is therefore needed to study the effects of these discharges and how water quality of the Tigris River could be managed. To address this issue, CE-QUAL-W2 was used to develop a 2-D (longitudinal and vertical) hydrodynamic and water quality model of the mainstem Tigris River from Mosul Dam (Rkm 0) to Kut Barrage (Rkm 880). In addition, Tharthar Lake and its canals were modeled. A full suite of hydrodynamic and water quality variables were simulated for the year 2009, including flowrates, water level, and water temperature. Additionally, water quality constituents such as total dissolved solids (TDS), phosphate (PO4), ammonium (NH4), nitrate (NO3), biochemical oxygen demand (BOD), chlorophyll-a (Chl-a), and dissolved oxygen (DO) were also simulated. Bathymetry of the Tigris River and field data such as flowrate, water level, TDS, NO3 were obtained from the Ministry of Water Resources in Iraq, while surface water temperatures of the Tigris River were estimated remotely using Landsat satellites. These satellites provided a continuous observation record of remote sites. Other water quality field data, such as PO4, NH4, BOD, and DO, were estimated from literature values. Meteorological data, including, wind speed, wind direction, air and dew point temperatures, cloud cover, and solar radiation were obtained from the Iraqi Ministry of Transportation, the General Organization for Meteorology and Seismic Monitoring. Model predictions of flow and water level were compared to field data at three stations along the mainstem of the Tigris River, including Baeji, downstream of Samarra Barrage, and Baghdad. The absolute mean error in the flow varied from 12.6 to 3.4 m3/s and the water level absolute mean error varied from 0.036 to 0.018 m. The percentage error of the overall flowrate at Baeji, downstream Samarra Barrage and Baghdad was 1.9%, 0.8%, and 0.8% respectively. Injecting a conservative tracer at Mosul Dam showed that a parcel of water reaches to Baeji, Samarra Barrage, Baghdad, and Kut Barrage after approximately 3 days, 5 days, 10 days, and 19 days, respectively. Water temperature field data in Iraq are limited and there was no archive of existing field data. Therefore, I obtained estimates of surface water temperature on the Tigris River using the thermal band of the Landsat satellite, one of a series of satellites launched by the National Aeronautics and Space Administration (NASA). The calibration between satellite data and water temperature was validated using sparse field data from 2004, and the calibration then applied to 82 Landsat images from the year 2009. Landsat estimates showed a bias of -2°C compared to model results in winter months, possibly due to uncertainty in Landsat estimations. The absolute mean errors of the CE-QUAL-W2 model predictions of water temperature compared to Landsat estimated temperatures were 0.9 and 1.0°C at Baeji and Baghdad respectively. Temperature calibration in the Tigris River system was highly sensitive to meteorological input data. Landsat Images were also used to estimate longitudinal variation in surface water temperature of Tharthar Lake. It was found that surface water temperature in Tharthar Lake varied longitudinally along the North-South axis with warmer temperatures in the lower part compared with the upper part of the lake. Total dissolved solids concentrations in the Tigris River significantly increased from Mosul Dam to Kut Barrage with peak concentrations of 900 mg/l and 1050 mg/l at Baghdad and Kut, respectively, due to high TDS water diverted from Tharthar Lake, irrigation return flow, urban runoff, and uncontrolled discharge of wastewater effluents. NO3 concentrations did not significantly increase between Samarra Barrage and Baghdad city. BOD concentrations within Baghdad were extremely high due to direct discharge of industrial wastewater into the mainstem of the Tigris River from outlets located within the city. Management scenarios were simulated with the model of the Tigris River system and were compared with the base model. The main scenarios implemented on the Tigris River system were altering upstream hydrology, increasing air temperature due to the effect of climate change, disconnecting Tharthar Lake from the Tigris River system, and simulating long-term effects on Tharthar Lake. Increasing upstream inflows caused a decrease in TDS concentrations from 495 mg/l to 470 mg/l over all the mainstem of the river. In addition, CBOD concentrations decreased somewhat from 5.9 mg/l to 5.74 mg/l. On the other hand, decreasing upstream flows caused a significant increase in average TDS concentrations over the entire Tigris mainstem from 495 mg/l to 527 mg/l. Also, an increase in CBOD concentrations from 5.9 mg/l to 6.2 mg/l was predicted over all the mainstem of the river. Implementing the climate change scenario on the base model of the Tigris River system showed a 5% increase in annually averaged water temperature from 20.7°C to 21.68°C over the mainstem river. Climate change scenarios produced no significant impacts on TDS and CBOD concentrations in the mainstem, while DO concentrations decreased from 8.15 mg/l to 7.98 mg/l with a slight increase in Chl-a concentration from 1.97 µg/l to 2 µg/l in the mainstem. Disconnecting Tharthar Lake from the system showed a remarkable 25% decrease in TDS concentrations, with an average concentration changed from 495 mg/l to 397 mg/l in the mainstem due to an extra 36% increase in flow discharged downstream of Samarra Barrage. Also, Chl-a concentration significantly decreased by 40% with an average concentration changed from 2 µg/l to 1.2 µg/l. Additionally, a 6-year model simulation of the Tigris River system was performed to evaluate the long-term effects on Tharthar Lake. No significant impact was observed in the average temperature of the lake. TDS concentrations in the lake decreased from 1239 mg/l to 1041 mg/l. PO4, NH4 and NO3 concentrations decreased by 2%, 66% and 26%, respectively. Chl-a concentration in Tharthar Lake decreased from 2.0 µg/l to 1.61 µg/l. After decreasing BOD concentrations of the Tigris River by 50%, BOD concentrations in the mainstem decreased by 24%, while DO concentrations increased by 2.8%. There were no significant impacts on Chl-a concentrations in the mainstem of the river. Finally, for a scenario where extremely low dissolved oxygen release from Mosul Dam in the summer, it was found that approximately 50 km below Mosul Dam was affected before DO concentrations reached an equilibrium concentration. For further work on the Tigris River system, it is recommended to model the Tigris River from Kut Barrage to the confluence with the Euphrates River, about 400 km long, and connect it with the current model to have a complete model of the Tigris River system from Mosul Dam to the confluence with the Euphrates River. This is necessary to manage water the entire system of the Tigris River and also to provide enough water with good quality in Basra.
297

Participatory decision making : new democracy or new delirium?

Spriggs, Shelley, University of Western Sydney, Hawkesbury, Faculty of Environmental Management and Agriculture January 1999 (has links)
Ever since the laborious consultation process to set the National Greenhouse Response Strategy (1991-1992), stakeholder 'consultation' has been something Australian governments do. Or attempt to do. A recent trend in NSW in particular has been to expand the concept and practice of consultation to multi-party, collaborative decision-making, also referred to as participatory democracy. One such initiative officially begun in August 1997 is the River Management Committee (RMC) exercise. For this tremendous outlay of financial and human resources, the government is taking a punt that the committee will deliver better decisions, and more timely actions, on river flows and water quality in each of the major regulated river valleys in the state. The set up and first year of operation of the RMC exercise is the subject of this thesis. Specifically it examines the design of the process and its appropriateness to the task at hand; the reality of consensus decision-making amongst people with opposing views; the democratic ideal of participants learning to be 'other directed' in terms of putting aside their own positions to work for the common good; and affordability of such exercises from both the government and non-government participants' points of view. The themes emerging from this thesis have become the focus for further research. / Master of Science (Hons)
298

Engineering solutions to water quality problems in lakes

Morillo, Sebastian January 2008 (has links)
Lake restoration and management strategies focus on reducing the negative impacts of enriched or polluted inflows. These strategies become of paramount importance when lakes are used for recreational and/or drinking water purposes. Long term control of eutrophication and turbidity problems associated with large inflow loads is usually oriented to catchment management. Although it has been suggested that this is the correct long term approach, public concerns usually require a short term solution. In addition, due to political and economic costs related to changes in catchment management, in-lake restoration technologies have been emerging as a viable pretreatment option, complementary to water treatment plants, both reducing the operational costs of the water treatment plant and ameliorating the water residing in the lakes. This research investigates the effects of two in-lake technologies on the dynamics of inflowing rivers, where basin shape plays a significant role. The three lakes in this study suffer from eutrophication combined with a distinctive water quality problem: from turbidity in Silvan Reservoir (Australia), to heavy metal loads in Coeur d'Alene Lake (USA) and industrial wastes in Lake Como (Italy). Firstly, the influence of basin morphology, wind speed, and wind direction on the fate and transport of two rivers flowing into the L-shaped Coeur d'Alene Lake was examined, and it was shown that transport and mixing patterns in a lake can be greatly influenced by the shape of the lake, leading to important consequences for the plankton ecology in the lake. Secondly, in Silvan Reservoir we investigated the potential to modify the basin shape using vertical barriers, increasing the retention time and hence the barrier capacity to microbial pollution. A final in-lake technology was tested for Lake Como, using a downward pointing impeller to remove polluted water from the coastal margin. Lessons from these three examples indicate that there is significant potential for in-lake remediation at relatively low cost, over relatively short timescales.
299

Deciding to Recharge

Eden, Susanna January 1999 (has links)
Public water policy decision making tends to be too complex and dynamic to be described fully by traditional, rational models. Information intended to improve decisions often is rendered ineffective by a failure to understand the process. An alternative, holistic description of how such decisions actually are made is presented here and illustrated with a case study. The role of information in the process is highlighted. Development of a Regional Recharge Plan for Tucson, Arizona is analyzed as the case study. The description of how decisions are made is based on an image of public water policy decision making as 1) a structured, nested network of individuals and groups with connections to their environment through their senses, mediated by their knowledge; and 2) a nonlinear process in which decisions feed back to affect the preferences and intentions of the people involved, the structure of their interactions, and the environment in which they operate. The analytical components of this image are 1) the decision makers, 2) the relevant features of their environment, 3) the structure of their interactions, and 4) the products or outputs of their deliberations. Policy decisions analyzed by these components, in contrast to the traditional analysis, disclose a new set of relationships and suggest a new view of the uses of information. In context of information use, perhaps the most important output of the decision process is a shared interpretation of the policy issue. This interpretation sets the boundaries of the issue and the nature of issue-relevant information. Participants are unlikely to attend to information incompatible with the shared interpretation. Information is effective when used to shape the issue interpretation, fill specific gaps identified as issue-relevant during the process, rationalize choices, and reshape the issue interpretation as the issue environment evolves.
300

Faecal water pollution loads as a function of population growth in Sedibeng and Soshanguve, South Africa.

Teklehaimanot, Giorgis Zekristos. January 2013 (has links)
M. Tech. Water Care. / Aims determining whether inadequate treatment of wastewater and the faecal pollution load of effluents and receiving water bodies in Sedibeng District and Soshanguve peri-urban area of Tshwane Metropolitan Municipality were a function of population growth. To achieve the aim of this study, the following objectives were pursued: Assess the variation in nutrient load and compliance of the physicochemical quality of effluents and receiving water bodies in terms of the South African and World Health Organization standards. Furthermore, the water quality index was also used to assess the overall physicochemical quality status of effluent and receiving water bodies. Assess the compliance of the microbial quality of effluents of the four wastewater treatment plants and their respective receiving water bodies in terms of the South African and World Health Organization limits. Determine the prevalence of Salmonella Typhimurium, Shigella dysenteriae and Vibrio cholerae in the targeted wastewater treatment works effluent and their respective receiving water bodies. Determine the possible public health risks of Escherichia coli, Salmonella Typhimurium, Shigella dysenteriae and Vibrio cholerae infections that could be acquired due to ingestion of or exposure to untreated water from the targeted receiving water bodies. Capture information regarding population growth and wastewater treatment plants in Sedibeng District and Soshanguve peri-urban area of Tshwane Metropolitan Municipality and determine whether under performance of the targeted wastewater treatment works could be attributed to population growth.

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