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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.
191

On the Distributional Implications of Safe Drinking Water Standards

Cory, Dennis C., Taylor, Lester D. 28 March 2017 (has links)
The provision of safe drinking water provides a dramatic example of the inherent complexity involved in incorporating environmental justice (EJ) considerations into the implementation and enforcement of new environmental standards. To promote substantive EJ, implementation policy must be concerned with the net risk reduction of new and revised regulations. The regulatory concern is that higher water bills for low-income customers of small public water systems may result in less disposable income for other health-related goods and services. In the net, this trade-off may be welfare decreasing, not increasing. Advocates of Health–Health Analysis have argued that the reduction in health-related spending creates a problem for traditional benefit-cost analysis since the long-run health implications of this reduction are not considered. The results of this investigation tend to support this contention. An evaluation of the internal structure of consumption expenditures reveals that low-expenditure households can be expected to react to an increase in the relative price of housing-related goods and services due to a water-rate hike by reducing both housing and health-related expenditures. That is, the representative low-expenditure household re-establishes equilibrium by not only decreasing housing-related spending, but also by decreasing spending on health-related expenditures in a modest but significant way. These results reflect the fact that expenditures on housing are a major proportion of overall household spending, and that accommodating drinking water surcharges exacerbates both health and food security concerns for low-expenditures households.
192

Biofilm Detection through the use of Factor Analysis and Principal Component Analysis

Unknown Date (has links)
Safe drinking water is paramount to a healthy society. Close to a hundred contaminants are regulated by the government. Utilities are using chloramines to disinfect water to reduce harmful byproducts that may present themselves with the use of chlorine alone. Using chlorine and ammonia to disinfect, ammonia oxidizing bacteria can present themselves in an unsuspecting utilities distribution network. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection
193

Dispersive liquid-liquid micro-extraction coupled with gas chromatography for the detection of trihalomethanes in different water sources in the Western Cape, South Africa

Lane, Marshalle January 2018 (has links)
Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2018. / Trihalomethanes (THMs) are a group of four compounds that are formed, along with other disinfected by-products. This happens when chloride or other disinfectants are used to control microbial contamination in drinking water, which then reacts with natural organic or inorganic substances in water. Trihalomethanes are better known by their common names such as chloroform, bromodichloromethane, chlorodibromomethane and bromoform. These four compounds are known to be classified as cancer group B carcinogens (shown to cause cancer in laboratory animals). Trihalomethane levels tend to increase with pH, temperature, time and the level of “precursors" present. Precursors are known to be organic substances which react with chloride to form THMs. One significant way of reducing the amount of THMs in water is to eliminate or reduce chlorination before filtrations and reduce precursors. There are guideline limits for THMs in the SANS 241:2015 document, but they are not continuously monitored and their levels in natural water are not known. The aim of this study is to develop a rapid, fast and reliable liquid-liquid microextraction technique, to determine the presence of THMs in natural water sources. This study particularly focuses on different water sources e.g. river, underground, borehole and chlorinated water. Chlorinated water is the water that has been presumably treated for bacteria and fungus growth. The results that were obtained for chlorinated water are as follow, 10.120 μg/L − 11.654 μg/L for chloroform, 2.214 μg/L - 2.666 μg/L for bromodichloromethane, 0.819 μg/L − 0.895 μg/L chlorodibromomethane and 0.103 μg/L - 0.135 μg/L for bromoform from validation data. All these THMs concentrations have been found to be below the SANS 241:2015 limits. Natural water shows a very high affinity for chloroform. This is what is expected under normal conditions as chloroform is the most abundant THM of all THMs present in natural water. The liquid-liquid microextraction technique that was optimized and used for the determination of THMs in this study is a rapid, simple and inexpensive technique that provides low limits of detection (LOD) e.g. 0.1999 μg/L chlorodibromomethane and 0.2056 μg/L bromoform and wide dynamic range (LOQ) of 0.6664 μg/L chlorodibromomethane and 0.6854 μg/L bromoform for the determination of THMs.
194

Short term forecasting of algal blooms in drinking water reservoirs using artificial neural networks / Hugh Edward Campbell Wilson.

Wilson, Hugh Edward Campbell January 2004 (has links)
"April 2004" / Bibliography: p. 285-299. / xxviii, 299p : ill., map ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Artificial neural networks (ANNs), trained to make short term forecasts of algal blooms in lakes and rivers, are potentially useful decision making tools for the operational management of eutrophication. This thesis addresses the question of whether a standardised, gemeric ANN model representation can be developed to achieve this goal. It is argued that four requirements need to be addressed: i) compatibility of models with existing water quality monitoring regimes, ii) stability and repeatability of training outcomes, iii) realistic and meaningful estimates of model performance, and iv) explanation of predictions. / Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Environmental Biology, 2004
195

Dricksvattenkvalite i enskilda vattentäkter : Landskrona kommun

Larsson, Martin January 2008 (has links)
<p>Denna rapport är en sammanställning av de 100 undersökta enskilda brunnarna i Landskrona kommun vid årsskiftet 05/06. Det utfördes analyser på mikrobiologisk-, nitrat-, nitrit- och även kemiska bekämpningsmedelspåverkan. Syftet med denna rapport är att bearbeta och presentera analysresultaten av de 100 enskilda brunnarna i Landskrona kommun och försöka dra slutsatser kring dessa. Alla analysresultaten sammanställdes i tabeller och så småningom kundes vissa slutsatser dras kring varför resultatet såg ut som det gjorde. Resultatet visade att endast åtta av de 100 brunnarna var otjänliga gällande mikrobiologisk påverkan. Denna parameter är väldigt varierande beroende mycket på yttre omständigheter men det kan ge en indikation på att brunnen inte är tillräckligt tät och därför kan ytvatten tränga in i brunnen. När det gäller nitritpåverkan blev bara en brunn otjänlig. Men när det gällde nitrat var det istället 17 % av brunnarna som visade sig vara otjänliga. Detta är ändå ett relativt bra resultat beroende på hur landskapet ser ut i Skåne med stor påverkan från enskilda avlopp, jordbruk och gödsling. Sist men inte minst analyserades kemiska bekämpningsmedel och gav ett oroande resultat. Hela 35 % av brunnarna var otjänliga pga. kemiska bekämpningsmedel. Detta resultat är inget ovanligt utan kan genom danska undersökningar bara bekräftas. Kemiska bekämpningsmedel kan sprida sig långa sträckor och inte bara vid den plats där ämnena använts eller spillts. De slutsatser som kan dras genom denna undersökning är att grävda brunnar i ytliga jordlager löper störst risk att i framtiden bli otjänliga då dessa utsetts för störst påverkan av föroreningar och ytvatten. Brunnar placerade på gårdsplan är speciellt utsatta och är starkt påverkade av både mikroorganismer och kemiska bekämpningsmedel. När det gäller kemiska bekämpningsmedel är resultaten från Landskrona liknande de från både Danmark och övriga Skåne.</p> / <p>The problem with bad drinking water in wells are a wide problem in an landscape such as Skåne. The purpose of this report is to work up all the data from the different analysis regarding drinking water quality from wells in Landskrona municipality. The parameters that were analysed were microorganisms, the content of nitrate and nitrite and also the concentration of pesticides. Many reports in the field of the subject were collected to get a good picture and a better knowledge of the different problems that lie ahead. This resulted in various conclusions but some of the conclusions was confirmed from other examinations. That wells in the ground are more exposed than wells in mountain. The concentration of pesticides were very high in many of the wells wich shows that this will be a great problem for us to deal with in the future. Examinations in both Denmark and remaining parts of Sweden also show high concentration of pesticides. This only confirm that the problem isn’t just a local here in the municipality.</p>
196

Assessing the Treatment Efficiency of Advanced Purification Processes and the Feasibility of Wastewater Recycling in Three Drinking Water Treatment Plants

Lin, Yung-chang 07 August 2007 (has links)
The purposes of this study are¡G(1) comparing the treatment efficiency with advanced and traditional drinking water treatment plants in southern Taiwan¡F(2) assessing the treatment efficiency and formation of disinfection by-products in advanced water treatment processes¡F(3) assessing the feasibility of wastewater recycling and treatment efficiency of wastewater treatment units¡F(4) evaluating corrosion of drinking water transportation pipelines and reproducing of chlorination by-products. This study found that the removal efficiency of turbidity, iron, manganese, coliform group and total bacterial count were approximately 99% by advanced and traditional purification processes. The concentrations of ammonia-N (NH3-N), nitrite nitrogen and nitrate nitrogen were lower drinking water quality standard. Pellet softening process was designed following coagulation/sedimentation unit to increase 8~14% and 6~20% removal efficiency of alkalinity and total hardness (TH) concentrations. The removal efficiency of total dissolved solids (TDS) was approximately 3~15% by advanced water treatment processes better than traditional water treatment processes. In the formation of disinfection by-products (DBPs), the trihalomethanes (THMS) and haloacetic acid (HAA5) were efficiently decreased by advanced purification processes. Bromate concentrations which lower detection limit were treated by ozonation process during the study periods. Advanced treatment processes should control the dosage of ozone and post-chlorine to avoid production of DBPs. In wastewater reuse, the treatment efficiency of suspended solids (SS) was 48¡ã99%, respectively, showing the significant removal efficiency of the wastewater process. However, the removal efficiencies of NH3-N, total organic carbon (TOC) and chemical oxygen demand (COD) are limited by wastewater treatment processes. Because NH3-N, TOC and COD of the mixing supernatant and raw water are regulated raw water quality standards, supernatant reuse is feasible and workable during wastewater processes at this plant. Overall, analytical results indicated that supernatant reuse is feasible. The Chengcing Lake water treatment plant significantly reduced alkalinity, Ca2+ concentration and TH concentration via pellet softening treatment: however, reducing the Langelier saturation index (LSI) value of water could cause some adverse effects on distribution systems. Operational conditions by Pingding water treatment plant was added base to water can be tried to adjust pH to maintain a slightly positive LSI value, whereas for water with low hardness and alkalinity.
197

The effects of using a cation exchange water softener on blood pressure

Kang, Ki Sung 29 August 1990 (has links)
Water in 70 percent of the cities in the United States is hard enough that softening is either required or recommended. It is estimated that approximately 30 percent of all homes in the United States use water softeners. Water softeners, the cation exchange types suited for residential use, exchange sodium for the calcium and magnesium in water. The increase in sodium levels in the softened water caused by cation exchange softening is a direct function of the hardness level of the untreated water. For people who use groundwater, which has a relatively high level of naturally occurring sodium, magnesium and calcium, the additional sodium from cation exchange water softeners may create health hazards for the general population and could adversely affect those who are sensitive to salt or on low sodium diets. To prevent potential health hazards for the general population, no consumption of softened water by cation exchange water softeners should be recommended. If soft water is needed for some practical reasons, a "Separate Water Line System" should be recommended for homeowners. / Graduation date: 1991
198

The capacity of Montreal Lake, SK to provide safe drinking water

Lebel, Pierre Mathieu 30 April 2008
Recent waterborne disease outbreaks in Canada have brought national awareness to drinking water safety. In particular, the long history of poor water quality plaguing First Nations communities has received substantial public attention. Despite several initiatives from the federal government and considerable financial support, the quality of drinking water on reserves has shown little improvement and continues to pose health risks. As a result, there is a growing interest in the ability of First Nations communities to effectively manage their drinking water resources. The purpose of this study was to assess the capacity of Montreal Lake, SK to provide its residents with safe drinking water, both now and into the future. This research employed a mixed methods approach in the examination of the communitys water system and management practices. Data sources included individual interviews, a public workshop, documents and inspection reports, and water quality data. Water system capacity was considered in terms of financial, human resources, institutional, social/political, and technical dimensions. An analytical framework was developed through a literature review where each dimension of capacity was rated based on a series of indicators. It was determined that there are no serious deficiencies in the management of Montreal Lakes drinking water. However, a number of flaws in each aspect drinking water management were detected. These include weak linkages between the agencies responsible for drinking water provision, and a low level of drinking water safety for community residents served by the truck haul distribution system. This research confirms the multi-dimensional aspects of water system capacity, reveals the necessity for the different levels of authority to work together, and provides an analytical framework which may be applicable to future studies examining First Nations and small-scale drinking water systems.
199

Body Fluid Analogues and Personal Care Products as Potential DBP Precursors

Wang, Zhen 25 August 2011 (has links)
Disinfection byproducts (DBPs), such as organic chloramines, THMs, HAAs, and nitrosamines, are formed during mandatory disinfection processes in drinking water treatment. Many of these DBPs have been shown to be potentially carcinogenic. Extensive research has been conducted on the occurrence and formation of these DBPs. However, there has been limited research on their relationships with each other, which may be important for the understanding of their formation mechanisms, and the nature of their precursors is still relatively unknown. Ultimately, this information will be key for the development of possible improvements in treatment technologies. Results of this study improve the understanding of DBP formation in swimming pool water. Some BFAs and PCP additives were identified as potential DBP precursors. Influence of BFAs and PCP additives on DBP formation in swimming pool water was also illustrated. Results provided feasible strategies to minimize DBP formation while maintaining the efficiency of disinfection.
200

Body Fluid Analogues and Personal Care Products as Potential DBP Precursors

Wang, Zhen 25 August 2011 (has links)
Disinfection byproducts (DBPs), such as organic chloramines, THMs, HAAs, and nitrosamines, are formed during mandatory disinfection processes in drinking water treatment. Many of these DBPs have been shown to be potentially carcinogenic. Extensive research has been conducted on the occurrence and formation of these DBPs. However, there has been limited research on their relationships with each other, which may be important for the understanding of their formation mechanisms, and the nature of their precursors is still relatively unknown. Ultimately, this information will be key for the development of possible improvements in treatment technologies. Results of this study improve the understanding of DBP formation in swimming pool water. Some BFAs and PCP additives were identified as potential DBP precursors. Influence of BFAs and PCP additives on DBP formation in swimming pool water was also illustrated. Results provided feasible strategies to minimize DBP formation while maintaining the efficiency of disinfection.

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