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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.
11

Substainable water resource management in Singapore /

Tang, Sidney. January 2001 (has links) (PDF)
Thesis (M.Env.St)--University of Adelaide, Dept. of Geographical and Environmental Studies, 2001. / Bibliography: leaves 61-64.
12

Optimal reservoir operation for drought management

Kleopa, Xenia A. January 1990 (has links)
Thesis (M.S.)--Ohio University, March, 1990. / Title from PDF t.p.
13

Endocrine disruption in the fathead minnow (Pimphales promelas) following a series of upgrades to a wastewater treatment facility

Baroffio, Angelina Free 16 December 2015 (has links)
<p>This study aimed to characterize the impact of treatment infrastructure upgrades on the occurrence of endocrine disrupting chemicals (EDCs) discharged by a wastewater treatment plant (WWTP) effluent and their subsequent effects on fish endocrine function. This site has been evaluated before and after two major upgrades in wastewater treatment infrastructure, which were implemented in 2007 and 2012. Our study assessed the potential impacts on the Boulder Creek receiving water, as well as identified and evaluated the extent of estrogenic endocrine disruption in the native fathead minnow (Pimephales promelas) that may be occurring after the implementation of the 2012 upgrade. We conducted an integrative, 8-week, on-site, continuous-flow, exposure experiment using adult male fathead minnows to assess in vivo estrogenicity of the WWTP effluent water, relative to reference water and results from prior years (both pre- and post-upgrade). We collected data for a wide array of biological endpoints. Results for plasma vitellogenin concentrations and sperm development were emphasized. It was found that in vivo effluent estrogenicity following the 2012 upgrade was insignificant in comparison to pre-upgrade levels. However, the occurrence of an extreme flood event in the Boulder area resulted in the detection of some significant effluent estrogenicity, indicating that such conditions may impact the ability of WWTPs to effectively remove estrogenic EDCs from the effluent.
14

Comparison of Bacterial and Viral Reduction across Different Wastewater Treatment Processes

Vagadia, Aayushi R. 17 January 2019 (has links)
<p> Today billions of people live without access to basic sanitation facilities, and thousands die every week due to diseases caused by fecal contamination associated with improper sanitation. It has thus become crucial for decision makers to have access to relevant and sufficient data to implement appropriate solutions to these problems. The Global Water Pathogen Project <u> http://www.waterpathogens.org/</u> is dedicated to providing an up-to-date source of data on pathogen reduction associated with different sanitation technologies that are important if the world is to achieve the Sustainable Development Goals (SDGs) related to health and sanitation provision. In this research, a subset of the Global Water Pathogen Project (GWPP) data is used to access the reduction of bacteria and viruses across different mechanical and natural sanitation technologies. The order of expected removal for bacteria during wastewater treatment was reported as highest for a membrane bioreactor (4.4 log10), waste stabilization pond (2.3 log10), conventional activated sludge (1.43 log10), anaerobic anoxic oxic activated sludge (1.9 log10), trickling filter (1.16 log10), and upflow anaerobic sludge blanket reactor (1.2 log10). </p><p> Furthermore, the order of expected removal for viruses was reported as highest for a membrane bioreactor (3.3 log10), conventional activated sludge (1.84 log10), anaerobic anoxic oxic activated sludge (1.67 log10), waste stabilization pond (1 log10), upflow anaerobic sludge blanket reactor (0.3 log10) and trickling filter (0.29 log10). It was found that hydraulic retention time (HRT) had a statistically significant relation to the reduction of bacteria in an anaerobic, anoxic oxic treatment system. Similarly, a significant relation was found between the number of waste stabilization ponds in series and the expected reduction of bacteria. HRT was also found to be a significant factor in virus reduction in waste stabilization ponds. Additionally, it was observed that waste stabilization ponds, trickling filters, and UASB reactors could obtain a greater reduction in bacteria (5&ndash;7 log10) when combined with additional treatment (e.g., chemical disinfection or use of maturation ponds). Also, mechanized systems, such as activated sludge systems and membrane bioreactors, obtained a greater reduction (2&ndash;3 log10) of viruses when compared to a natural system. It was concluded that the selection of the best suitable technology for pathogen reduction depends on environmental, design, and operational factors as well as considering the performance of specific wastewater treatment systems individually as well as when combined with other treatment technologies that may provide added removal of microbial constituents. </p><p>
15

Source Protection and Drinking Water Quality in the Comarca Ngabe-Bugle, Panama

Miller, Leigh Burgess 23 June 2017 (has links)
<p> The goal of this study was to identify practical, cost-effective drinking water source protection measures in the Comarca Ng&auml;be-Bugl&eacute;, a remote indigenous region of Panama. Water samples from 40 spring captures were tested for <i>E. coli</i> and total coliforms, and quality results were then compared with maintenance and source protection criteria using odds ratios. The water was contaminated; only two samples passed Panamanian drinking water standards--0 CFU/100 ml for <i>E. coli</i> and 3 CFU/100 ml for total coliforms. Mean <i>E. coli</i> was 187 CFU/100 ml and mean total coliforms was 2036 CFU/100 ml. Few odds ratio tests of source protection practices produced statistically significant results. However, the presence of animals within ten meters of the source and cleaning out the spring capture structure had statistically significant relationships with water quality at some contamination thresholds. Surprisingly, at one threshold, the presence of surface water near the spring was unrelated to water quality. Protecting water sources from livestock can be complicated in this region by ambiguous land tenure laws. Likewise, cleaning and basic maintenance are often done on a volunteer basis, and thus subject to the limitations of the community management model. Panamanian and foreign organizations seeking to improve drinking water source quality should consider these complex issues and offer financial and technical support as they encourage source protection improvements.</p>
16

A Novel Aquatic Sensor and Network

Davis, James 19 January 2017 (has links)
<p> Water quality monitoring is essential to human health, ecological stability, and scientific research but remains hampered by Large, expensive, inflexible, and sometimes unreliable systems. To address these problems, an open source, flexible, and inexpensive sonde was designed and created capable of meeting research needs, along with a buoy system to support its use. A new optical UV based sensor was created to help measure phosphate ion levels. Together these technologies could further ecological research and help safeguard ecosystems.</p>
17

Analysis of Uncertainty in Water Management and Wastewater-based Population Health Assessments

January 2019 (has links)
abstract: Uncertainty is inherent in predictive decision-making, both with respect to forecasting plausible future conditions based on a historic record, and with respect to backcasting likely upstream states from downstream observations. In the first chapter, I evaluated the status of current water resources management policy in the United States (U.S.) with respect to its integration of projective uncertainty into state-level flooding, drought, supply and demand, and climate guidance. I found uncertainty largely absent and discussed only qualitatively rather than quantitatively. In the second chapter, I turned to uncertainty in the interpretation of downstream observations as indicators of upstream behaviors in the field of Wastewater-Based Epidemiology (WBE), which has made possible the near real-time, yet anonymous, monitoring of public health via measurements of biomarkers excreted to wastewater. I found globally, seasonality of air and soil temperature causes biomarker degradation to vary up to 13-fold over the course of a year, constituting part of the background processes WBE must address, or detrend, prior to decision-making. To determine whether the seasonal change in degradation rates was introducing previously unaccounted for uncertainty with respect to differences in observed summertime and winter-time populations, I evaluated demographic indicators recorded by the Census Bureau for correlation with their distance from all major wastewater treatment plants across the U.S. The analysis identified statistically significant correlation for household income, education attainment, unemployment, military service, and the absence of health insurance. Finally, the model was applied to a city-wide case study to test whether temperature could explain some of the trends observed in monthly observations of two opiate compounds. Modeling suggests some of the monthly changes were attributed to natural temperature fluctuation rather than to trends in the substances’ consumption, and that uncertainty regarding discharge location can dominate even relative observed differences in opiate detections. In summary, my work has found temperature an important modulator of WBE results, influencing both the type of populations observed and the likelihood of upstream behaviors disproportionally magnified or obscured, particularly for the more labile biomarkers. There exists significant potential for improving the understanding of empirical observations via numerical modeling and the application of spatial analysis tools. / Dissertation/Thesis / Doctoral Dissertation Biological Design 2019
18

THE ROLE OF INTERNAL WATER STORAGE DESIGN ON NITROGEN FATE

Donaghue, Adrienne, 0000-0003-4927-3408 January 2021 (has links)
Green stormwater infrastructure (GSI) is implemented in urban landscapes to manage stormwater quantity and quality. Bioretention is an infiltration-based GSI strategy and demonstrates variable performance for total nitrogen (TN) removal. Internal water storage (IWS) is a sub-grade design feature that uses an underdrain with an elevated outlet to force a submerged layer. When a carbon source is present, often woodchips, IWS facilitates denitrification—the microbial reduction of nitrate (NO3-) to nitrogen gas (N2). This work considers the impact of IWS underdrain configuration, geometry, and IWS media on hydraulics, TN, and NO3- removal to enhance IWS design. To explore the impact of underdrain height, three laboratory columns with underdrains located at the bottom (0 cm), middle (15 cm), and top (30 cm) of a gravel-woodchip IWS were coupled with USGS VS2DRTI simulations. For narrow IWS geometries, width to depth (w/d) ratio < 1, hydraulic efficiency (ev) decreased from 1.0 to 0.76 as underdrain height increased from the bottom (0 cm) to top (30 cm). Changes in ev were attributed to the presence of immobile (low flow) zones below raised underdrains that limited solute transport. The presence of immobile zones impacted NO3- removal efficiency which decreased from 63% (bottom underdrain) to 32% (top underdrain) for a hydraulic loading rate (HLR) of 2.5 cm/h. However, simulated scenarios beyond the lab scale revealed ev varied less than 10% for IWS w/d ratios > 1 and indicated flow dynamics observed for narrow columns do not always translate to wider field systems. Under transient flow conditions, minimizing effluent NO¬3- concentrations and loads ranked least to greatest in the order bottom > middle > top underdrain configurations and dual isotopes in NO3- confirmed the presence of denitrification in mobile zones. Laboratory columns with bottom underdrain configurations considered three IWS media compositions of gravel, gravel-woodchip, and gravel-woodchip-biochar. Synthetic stormwater was modified to include dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and trace organic nitrogen compounds. Under continuous flow conditions, NO3- removal efficiency ranked in the order gravel-woodchip (78%) > gravel-woodchip-biochar (61%) > gravel (-10%) for a HLR of 2.5 cm/h. During antecedent dry periods, the gravel-woodchip-biochar and gravel-woodchip IWS removed NO3- within 18 hours following a transient event. However, the presence of biochar resulted in ammonium (NH4+) generation and effluent concentrations exceeded levels toxic to aquatic life. High-frequency field monitoring of an IWS with a raised underdrain was performed for eight storms over ten months. IWS nitrogen concentrations during storm events revealed that peak TN concentration generally occurred within the first hour during the rising limb of the IWS water level and that TN was likely exported from the system in the form of DON and NO3-. Additionally, NH4+ washout from unsaturated soil occurred during February through May and was attributed to sodium dispersion due to road salt application. This work coupled laboratory columns, modeling, and field studies to address the complexities of nitrogen management in bioretention as impacted by IWS underdrain height, geometry, ev, media selection, absorbent amendments, and seasonal patterns. When approaching IWS design for water quality enhancements, practitioners are encouraged to consider all these variables but recognize that the desired TN removal will not be achieved in some cases. / Environmental Engineering
19

Water governance: a solution to all problems

Franks, Tom R. January 2006 (has links)
Yes / Water governance is a widely-used but ill-defined term. Our objective throughout this seminar series has been to analyse what it does mean and to question the consensus that seems to attach to it. In this paper for the final seminar I discuss what governance is not, I suggest what it is and I consider some propositions and issues that seem to have emerged from our meetings. In doing this, I appreciate that governance can mean different things to different people, but I suggest that, used in a specific way, it is a concept with particular value and significance for water development. / ESRC
20

Water governance ¿ what is the consensus?

Franks, Tom R. January 2004 (has links)
Yes / The concept of water governance is a firmly established part of the consensus on international water development, and has become a constant theme in the policy processes we are discussing in this seminar. Originating in its present format at about the time of the second World Water Forum in 2002, it was specifically restated at the International Conference on Freshwater in Bonn, 2001 (¿the essential key is stronger, better performing governance arrangements¿), and it featured prominently in the outputs from the Third World Water Forum in Kyoto, 2003. In the Alternative Water Forum, held here in Bradford just after the Kyoto event, we encouraged participants to analyse and critically debate the underlying ideas, In this paper I want to encourage this continuing analysis and debate. Like many of the issues we shall be discussing over the next couple of days, I believe it repays closer consideration, and that it encompasses a set of important ideas which must not be lost in constant re-iteration of a general theme. / ESRC

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