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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.
511

Biological and chemical monitoring of three streams in the area of Blacksburg, Virginia

Hayles, Virginia Mosby 30 October 2008 (has links)
This study compares the sensitivity of biological and chemical parameters for monitoring water quality, examines several methods of analyzing diversity of the aquatic organisms and attempts to assess water quality in the three streams investigated. The Cairns-Dickson DI<sub>T</sub> diversity index was applied to two trophic levels of aquatic organisms and the results were compared to ascertain whether this diversity index is applicable to all levels of the trophic\structure or of greater use for a particular level. Two diversity indices, Cairns-Dickson DI<sub>T</sub> and Wilhm-Dorris d̅, were used to analyze the same component of the biological community and the results of these two indices were compared. A correlation test was performed among chemical and biological data and among chemical parameters. / Master of Science
512

Disinfectants and Plumbing Materials: Effects on the Sensory and Chemical Characteristics of Drinking Water

Durand, Monique Lucia 29 December 2005 (has links)
The distribution system is the primary cause of taste and odor complaints in drinking water. This research examined the ability of small diameter pipes used in home plumbing to affect drinking water quality. The properties of the materials were investigated in the absence of disinfectant and the presence of either chlorine or chloramines. A panel was trained in flavor profile analysis (FPA) according to Standard Methods 2170B and used to assess the sensory properties of all samples. Chemical analyses were performed to determine disinfectants, total organic carbon (TOC), pH and specific organic contaminants. The first part of this study investigated PEX pipes manufactured by the silane (PEX-b) and peroxide (PEX-a) cross-linking technology, using the utility quick test (UQT) method. Silane PEX-b had a greater effect on water quality properties such as odor, TOC and residual disinfectant demand than peroxide-linked PEX-a. Chemical analysis revealed that PEX pipes can contribute fuel oxygenates such as ETBE (PEX-b) and possibly MTBE (PEX-a) to drinking water. PEX pipes did not contribute any significant trihalomethanes to drinking water. This study showed that the type of PEX used in homes will determine the extent to which drinking water quality is affected. The second part of this study used simulated plumbing rigs to investigate seven different materials under low flow and stagnant conditions; chlorinated polyvinyl chloride, cross-linked polyethylene, polyethylene, epoxy-lined copper, copper, stainless steel, galvanized iron and glass (control). Results showed that these plumbing materials have the potential to affect water quality characteristics such as TOC concentrations, residual disinfectant and odor when newly installed in homes. A high TOC concentration was consistent with the presence of a distinct odor or a high FPA intensity rating. Galvanized iron produced the worst odors that were consistently described as "motor oil". Polyethylene generated more intense plumbing associated odors than PEX or cPVC plastic material. cPVC and copper generated the least odors. Both copper pipe and epoxy-lined copper consumed residual chlorine and chloramines. / Master of Science
513

Impact of an Epoxy Pipe Lining Material on Distribution System Water Quality

Pierce, Ryan Michael 16 June 2009 (has links)
Corrosion of iron and copper pipes can produce leaks and loss of efficiency in the water distribution system, elevate levels of contaminants at the tap, and cost billions of dollars annually in pipe replacement or rehabilitation. In situ pipe rehabilitation using cement mortar, polyurethane, and epoxy is a commonly employed method of dealing with aging yet structurally sound pipes because it is less expensive and less invasive than replacing pipe infrastructure. Although epoxy has been shown to be an effective solution to pipe corrosion, little research has been conducted regarding its impact on a comprehensive list of water quality parameters. This research addressed that gap in the literature by conducting short-term immersion tests in which new epoxy linings were exposed to reference tap waters containing one of three disinfectant treatments: no disinfectant, free chlorine, or chloramines. As a comparison, an aged epoxy-lined field sample was also tested. Water exposed to the liners under stagnant conditions was analyzed for the following water quality parameters: pH, ammonia, alkalinity, hardness, metals, disinfectant consumption, total organic carbon (TOC), semi-volatile organic compounds (SVOCs), disinfectant byproduct (DBP) formation, and odor. Results of the study showed relatively low impacts on water quality, as all USEPA drinking water regulations were met. Impacts were highest during the first 24 hour exposure period during which time significant disinfectant consumption was shown (> 90% free chlorine consumed, 13% chloramines consumed), high TOC was leached (2.6-6.2 mg/L), trihalomethanes and haloacetic acids were formed (both < 15 ug/L), Bisphenol-A, an endocrine disrupter, was detected (< 35 ug/L), and odor was reported by panelists at a moderate intensity and described as sweet/chemical/burning/chlorinous. Impacts were much less after the initial 24 hours, although odor remained noticeable throughout the 30 day study. Overall, water quality impacts were greatest in chlorinated waters and both new and aged epoxy showed slight differences in results. / Master of Science
514

Water Urbanism: Fish Market Design Proposal

Singh, Smakshi 09 February 2017 (has links)
The first civilizations we have ever heard of were along the banks of mighty rivers like Nile, Euphrates, Indus and Huang. These civilizations developed along rivers as riverfronts provided opportunities for tradeand transportation, fertile land to grow crops, water for drinking, washing, livestock and other domestic uses and food in the form of fish. Gradually, they came to define cities, became a part of identities of people, such as "India" from "Indus," while, providing a sense of place and connecting the populace to nature. Yet rivers have often ended up being abused and neglected in our course towards urbanization. It is this "neglect" that needs to be shunned. The relationship with the rivers needs to be re-forged. To develop a strategy for this shift in attitude, this research has chosen the case of Chesapeake Bay. Chesapeake Bay is an estuary lying inland from the Atlantic Ocean. It has mainland North America to its west and Delmarva Peninsula on the east. It is the largest Estuary in the United States. More than 150 major rivers and streams flow into the Chesapeake Bay. The estuary provides habitat to several species of wildlife and aquatic life. Today, this bay faces many issues such as nutrient and sediment pollution, Storm water runoff, lowering of shellfish species etc. One of the major causes of the polluted bay is storm water runoff. Storm water washes pollution off the roads and other surfaces and takes them to the water. Stormwater is generally more polluted in urban areas than rural areas. This thesis, attempts to demonstrate what can be done with a typical pixel in the whole mosaic of the bay . The Maine Avenue Fish Market, sitting just upstream to the now being developed Southwest Waterfront, seems a perfect choice for this endeavor. This market, a small urban waterfront space, is ideal for exploring ideas and solutions to avoid water pollution by stormwater, cleaning the quality of water and also, in the process, develop the area in relation to the city and its surroundings. This thesis aims to establish an ecological and social relationship between the natural resource and the urban life. / Master of Science / Rivers are extremely important to our eco system. They provide fertile land, water, opportunities for trade and transport, support various marine lives, provide an identity to a city or region etc. Inspite of being a vital component of our eco-system, rivers are being neglected and abused in our course towards urbanization. Today, rivers face several issues such as water pollution and lowering of marine life. In urban areas, water washes away pollution off the roads and flows into the river. This water run off from land is one of the major causes of the increasing water pollution. This thesis attempts to reduce water pollution by the suggesting sustainable methods to treat storm water, improving the quality of water, and also in this process develop the chosen site in respect to the city and revitalize the relation of the river of the city. The site I chose for this endeavor lies on the Potomac River of Washington DC. The Maine Avenue Fish Market, a small urban waterfront space, sitting just upstream to the now being developed Southwest Waterfront is being taken up to demonstrate possible ideas and solutions to clean the polluted Potomac River and also establish a relationship between the city and the river.
515

Optofluidic Detection of Aqueous Ammonia and Parasitic Cysts

Temkov, Melissa January 2022 (has links)
Water quality monitoring in Canada is essential to providing safe water to all. Indigenous and remote communities, many of which are under boiling drinking water advisories, lack availability and/or funding to water monitoring resources. A low-cost, point-of-care detection mechanism has been proposed for the detection of aqueous ammonia and protozoan parasites, which affect the safety of a source of water. An ammonia fluorescence responsive hydrogel, based on the fluorescence quenching of rare earth metal Europium (Eu3+) upon contact with aqueous ammonia, has been proposed to be incorporated into a microfluidic device, which utilizes shadow imaging and flow analysis to detect parasitic (oo)cysts of Cryptosporidium and Giardia, two of the most prevalent protozoan parasites which cause gastrointestinal illness around the world. Fabrication of the ammonia sensitive hydrogel was completed, and the essential components to the ammonia sensitivity were determined. Chemical analysis and solvent modifications found that Formamide is the essential solvent to maintain ammonia sensitivity. A literature review into the current detection mechanisms of Cryptosporidium and Giardia was completed to provide a reference and starting point for the development of the low-cost, point-of-care device proposed in this thesis. Baseline images of Cryptosporidium parvum and Giardia lamblia were captured to provide a reference for the development of a particle tracking algorithm to be used in the microfluidic device. The images captured highlight morphological features essential to developing a tracking mechanism based on the morphology of the (oo)cysts. / Thesis / Master of Science in Biomedical Engineering / Water quality monitoring for remote and Indigenous communities is needed to provide safe water to all. Detection of aqueous ammonia by fluorescent hydrogel, and parasitic cysts by flow analysis, provides a low-cost, point-of-care detection mechanism. A fluorescence responsive hydrogel for aqueous ammonia detection was produced and the essential components for ammonia responsiveness were determined. Detection mechanisms of parasites Cryptosporidium and Giardia, two of the most prevalent parasitic protozoans causing human gastrointestinal illness, were analyzed and compared. Baseline images of the parasitic (oo)cysts were captured by conventional microscopy for the training of particle tracking algorithms to be implemented into a microfluidic device. The microfluidic device detection mechanism will utilize shadow imaging and flow analysis to detect parasitic (oo)cysts.
516

Hydrogeology and contamination investigation of the West Branch of the Westport River Watershed

Hoagland, Matthew R. January 1988 (has links)
Thesis (M.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / Concentrations of enteric bacteria exceeding the State of Massachusetts water quality limits for shellfish harvesting without depuration have prompted the closure of nearly one third of the shellfish beds in the northern reaches of the West Branch of the Westport River Estuary. / 2999-01-01
517

A diagenetic two-layer eutrophication model for Tolo Harbour, Hong Kong

Feleke, Arega Woldemariam. January 2000 (has links)
published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy
518

A review of river water quality in Hong Kong

Cheng, Man-shun., 鄭文順. January 1998 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
519

A comparison of SAAS and chemical monitoring of the rivers of the Lesotho Highlands Water Project.

Rajele, Molefi Joseph January 2004 (has links)
The Lesotho Highlands Development Authority routinely uses the South African Scoring System version 4 (SASS4) in conjunction with water chemistry to monitor water quality of rivers in the Lesotho Highlands Water Project areas. The objective of this study was to test the efficiency of SASS4 in these areas.
520

Water quality trends in the Eerste River, Western Cape, 1990 - 2005.

Ngwenya, Faith January 2006 (has links)
<p>The Eerste River is a river system which has, over the years, been subjected to human interference. The purpose of this study was to investigatge temporal and spatial trends in the water quality of the Eerste River between 1990 and 2005. The study results revealed that the major trends in the water quality of the Eerste River are more spatial than temporal.</p>

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