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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.
161

River restoration in the upper Mississippi River Basin

O'Donnell, Thomas Kevin. January 2006 (has links)
Thesis (M.S.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 27, 2007) Includes bibliographical references.
162

Stormwaterbesoedeling in die Lourensrivier-opvanggebied

Habets, Maurice January 1993 (has links)
Thesis (Master Diploma (Civil engineering)--Cape Technikon, Cape Town,1993 / Stormwater pollution is a major problem in many of the areas where it is present. Due to the changing nature in terms of quality and quantity of stormwater, which has its origin in many different places, it is difficult to control and identify the source of pollution. Some of the pollutants present in stormwater run-off include oxygen-demanding substances, suspended solids, trace metals, toxic organic compounds (eg. chlorinated hydrocarbons), nutrients, refuse, plastics and pathogenic bacteria and viruses. This thesis identifies and discusses the problems in the Lourensriver catchment area, and produce practical solutions to decrease the pollution. The report consists of four sections. Part I : Part 2 : Part 3 : Part 4 : Evaluation of the existing area and identification of the problem. Literamre study. Control of Stormwater ie. storing, treatment and disposal. Presencation of steps to be followed to rectify the problem. If the findings and recommendations are followed, it should make a positive contribution to the wellbeing of the catchment area. The findings of this report could also be applied to areas with similar problems. The following recommendations are made for the Lourens River: " Monitor and strict implementation of the Wateract (1936). " In the Lower zone, pollution can be diluted and flushed out by ways of the closure of Melkschloot. " Design of any new development must take place in such a manner so as the stormwater discharge after development will be of the same quality and quantity as before construction. " Creation of permeable surfaces in established areas. " Delay of rainwater flow out of all areas. " Construction of additional sedimentation and detention dams for the storing and treatment of stormWater. " Awareness programmes to inform the public and industry. " Implementation of preventative measurements. " Establishment of controlling body's to ensure co-ordination betvieen various institutions and local government. " Monitor of run-off from industrial and agricultural terrain and identifying of unlawful practices. Strict anti-littering and dumping actions. Placing of waste storage bins in residential and industrial areas. Permits for the usage of poisons and the monitor there off. Encouragement of cleaning up actions and groups. Encouragement and increase of street cleaning operations. Construction of effective catchment basins to remove sol ids before it ends up in the stormwater pipes. Regular cleaning of catchment basins. Regular flushing of stormwater pipes. Construction of marshlands. Construction of reedbeds.
163

An integrated manual for the management, control and protection of the Vaal River Barrage reservoir

Van Wyk, Francois 29 January 2009 (has links)
M.Sc. / The Vaal River Barrage reservoir (VRBR) was constructed by Rand Water in 1923 for the purpose of ensuring an adequate raw water supply to meet the potable water requirements of the Pretoria, Witwatersrand and Vaal Triangle regions, and today this is still the main purpose of this body of water. Due to the strategic importance of the Vaal River Barrage catchment and the impact of activities in the catchment on water resources, it is seen as of the utmost importance for the authorities to make a joint effort and co-ordinate action to solve problems in the catchment. A number of different acts have reference to the management of the Barrage reservoir. These, together with Rand Water’s internal policies, are collated and described to provide a reference manual for the integrated management of the Vaal River Barrage reservoir. For completeness, all relevant policies are attached as appendices to the document.
164

The prediction of chlorine decay from potable water in pipeline systems

Viljoen, Ockert Jacobus 22 August 2012 (has links)
M.Ing. / The modelling of water quality in distribution systems is a relatively new field. It has become necessary to attend to the problem of water quality at the consumer's tap because water quality after treatment is not a guarantee for the water that reaches the consumer. It is increasingly important to design and manage distribution systems carefully to ensure safe drinking water up to the consumer's tap. This report gives the results and a discussion thereof on the chlorine decay in laboratory batch tests as well as on pipeline systems. Significant contributions were made to the different objectives of the study. Standardised test procedures for both free chlorine and monochloramine were developed. It was found that the n th-order, 1 parameter model described the decay of chlorine significantly better than did the generally assumed first order mathematical model. It was also found that the reaction orders are different for different water sources, and even different for the same water source at different times. It was also clear that the rate constants are dependent on temperature - the higher the temperature, the higher the decay rate constants. The reaction order for free chlorine varied from 0.36 to 1.22 with no apparent underlying pattern. For monochloramine, the reaction order fell into two distinctively different categories. For monochloramine decay up to 24 hours, the reaction order varied from 0.02 to 0.05. For monochloramine decay from 24 hours onwards, the reaction order varied from 0.92 to 0.95. As was expected, the free chlorine decay rates obtained in pipelines were higher than in parallel bulk decay rate tests. On the assumption that the bulk decay reaction order is equal to one, the mass transfer coefficient between the bulk flow and the pipe wall varied between 0.0065 m/h and 0.0457 m/h. Further research is highly recommended on the effect of secondary and tertiary chlorination as well as on more direct methods of estimating pipe wall-related chlorine reaction constants.
165

Isolation of Campylobacter from water and its fitness in an aquatic biofilm

Diergaardt, Sonya Marjorie 24 November 2005 (has links)
The full text of this thesis/dissertation is not available online. Please <a href="mailto:upetd@up.ac.za">contact us</a> if you need access. Read the abstract in the section 00front of this document. / Dissertation (MSc (Microbiology))--University of Pretoria, 2006. / Microbiology and Plant Pathology / unrestricted
166

Water quality monitoring of biological contaminants -- rapid, on-site detection technologies

Shimizu, Kristen N. M. 01 January 2012 (has links)
Access to a safe drinking water supply is a critical issue in a number of places across the globe. Conventional water quality monitoring technologies are slow, often taking at least two days to produce results. In recent years, there has been extensive research into emerging technologies that provide real-time results; however, there is no technology which detects all classes of biological contaminants. Biological contaminants are 5 particularly difficult to detect and quantify due to low concentrations typically present. It is not feasible to identify all biological contaminants present in a water supply; therefore, it is necessary to determine which are of highest concern based factors such as health significance, infectivity, and prevalence. The intent of this research is to evaluate microbiological detection methods and technologies based on their applicability for continuous real-time detection. This research will complement current research on biological water quality monitoring technologies for use in developing regions or in the event of an emergency and will provide suggestions for future research efforts.
167

Down the Drain: A Story of Sewage

Ekman, Lisa 01 January 2010 (has links)
This creative nonfiction thesis tells a story of how water turns into waste. With Portland, Oregon as a base, the reader visits a wastewater treatment plant, several buried and lost streams, a high-tech sewage processor, stormwater education classes, a stormwater management conference, several "green" streets, sewage construction zones, and sewage-related parks. The thesis explores how Western sewage systems came to be, and how wastewater management might change in the future.
168

Development of Hybrid Inexact Optimization Models for Water Quality Management under Uncertainty

Zhang, Qianqian January 2021 (has links)
Water quality management (WQM) significantly affects water use and ecosystem health, which is helpful for achieving sustainability in environmental and economic aspects. However, the implementation of water quality management is still challenging in practice due to the uncertainty and nonlinearity existing in water systems, as well as the difficulty of the integration of simulation and optimization analyses. Therefore, effective optimization frameworks for handling nonlinearity, various uncertainties, and integrated complex water quality simulation models are highly desired. This dissertation tries to address such challenges by proposing new efficient hybrid inexact optimization models for water quality management under uncertainty through: i) developing an interval quadratic programming (IQP) model for handling both nonlinearity and uncertainty expressed as intervals for water quality management, and solving the developed model by three algorithms to compare and investigate the most effective and straightforward solution algorithm for IQP-WQM problems; ii) developing a simulation-based interval chance-constrained quadratic programming model, which is able to deal with nonlinearity and uncertainties with multiple formats, and implementing a real-world case study of phosphorus control in the central Grand River, Ontario, Canada; iii) proposing a data-driven interval credibility constrained quadratic programming model for water quality management by utilizing a data-driven surrogate model (i.e., inexact linear regression) to incorporate a complex water quality simulation model with the optimization framework to overcome challenges from the integrated simulation-optimization. The performance of the proposed frameworks/models was tested by different case studies and various mathematical techniques (e.g., sensitivity analysis). The results indicate the proposed models are capable of dealing with nonlinearity and various uncertainties, and significantly reducing the computational burden from simulation-optimization analysis. Coupling such efforts in developing efficient hybrid inexact optimization models for water quality management under uncertainty can provide useful tools to solve large-scale complex water quality management problems in a robust manner, and further provide reliable and effective decision supports for water quality planning and management. / Thesis / Doctor of Philosophy (PhD) / Water quality management plays a key role in facilitating environmental and economic sustainability. However, many challenges still exist in practical water quality management problems, such as various uncertainties and complexities, as well as complicated integrated simulation-optimization analysis. Therefore, the goal of this dissertation is to address such challenges by developing a set of efficient hybrid inexact optimization models for water quality management under uncertainty through: i) developing an interval quadratic programming model for water quality management, and investigating its effective and straightforward solution algorithms; ii) leveraging the power of data-driven modeling and proposing efficient data-driven optimization models based on hybrid inexact programming for water quality management. Robust and effective water quality planning schemes for large-scale water quality management problems can be obtained based on the proposed frameworks/models.
169

Design Considerations for Extended Aeration-Denitrification Facilities

Huttner, Frank Paul 01 January 1974 (has links) (PDF)
Design considerations and operating procedures were investigated for nitrogen removal in an extended aeration-denitrification facility. Both past and present removal efficiencies were evaluated for the facility, along with capital and operating cost data. The findings of this research indicate that at very long detention times, significant nitrification and denitrification occurred in the plant without the use of chemicals. Overall nitrogen, BOD5, and suspended solids removals were extremely high. The significance of this research is that future plants may achieve high rates of nitrogen removal through innovative design and operating procedures without the use of costly chemicals. However, capital costs needed to achieve longer detention items will have to be evaluated for the individual plant.
170

Filtration of Detained Stormwater through Sand and Alum Sludge for Water Quality Control

Cassagnol, Claude L. 01 July 1980 (has links) (PDF)
Stormwater detention systems as they are frequently designed do not provide good water quality control of stormwater runoff. A filtration media to be used in conjunction with detention ponds to improve their pollutant removal efficiencies was tested at the University of Central Florida and found to be effective. The filtration media, which consisted of a mixture of sand and alum sludge, substantially improved effluent water quality. Average reductions of over 80 % were observed in concentrations of dissolved orthophosphorus, total orthophosphorus and total phosphorus. Reductions were also experienced in iron, aluminum, copper and zinc concentrations. A prototype filtration model is presently being tested on the Lake Eola watershed in Orlando, Florida. A stormwater management and design aid computer program originally written by Tim Curran (Curran 1980) to calculate stormwater hydrographs and retention volumes, and updated by the author to also calculate detention volumes will incorporate results from the prototype study.

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