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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.
1

What affects public acceptance of recycled and desalinated water?

Dolnicar, Sara, Hurlimann, Anna, Grün, Bettina 01 1900 (has links) (PDF)
This paper identifies factors that are associated with higher levels of public acceptance for recycled and desalinated water. For the first time, a wide range of hypothesized factors, both of socio-demographic and psychographic nature, are included simultaneously. The key results, based on a survey study of about 3000 respondents are that: (1) drivers of the stated likelihood of using desalinated water differ somewhat from drivers of the stated likelihood of using recycled water; (2) positive perceptions of, and knowledge about, the respective water source are key drivers for the stated likelihood of usage; and (3) awareness of water scarcity, as well as prior experience with using water from alternative sources, increases the stated likelihood of use. Practical recommendations for public policy makers, such as key messages to be communicated to the public, are derived. (authors' abstract)
2

Trace element contaminants in the Kuwait water production system

Al Anqah, Laila January 1996 (has links)
Fresh water in Kuwait is produced by non- conventional methods. About 95% of this water comes from desalinated seawater using multi-stage flash distillation technique and the remainder comes from underground brackish water. The blended water containes organic, inorganic and trace metal impurities within the recommended international standard limits. The purpose of this work is to identify the source of selected trace metals present in the drinking water in Kuwait. Chromium, copper, iron, lead, manganese, nickel, vanadium and zinc have been analysed using atomic absorption spectroscopy (AAS) and inductively coupled plasma mass spectroscopy (ICPMS). Efforts were made to improve the preconcentration of the selected metals and their separation from the high concentration of salts in seawater which affect the accuracy and cause major interference in the analysis. Solid-liquid extraction (chelex-100 resin) and liquid-liquid extraction (methyl iso-butyl ketone and freon) with and without back-extraction into nitric acid were investigated. Liquid-liquid extraction without back-extraction proved to give optimum recovery of the selected metals. Results confirmed that both AAS and ICP-MS are suitable for the analysis of trace metals in Kuwait's waters. Although AAS technique proved to be more accurate in analysing the selected metals than ICP-MS, the latter was adopted since its accuracy is acceptable (1.1-4.4%) and it is easier and faster than the former technique. The study revealed that the source of copper, iron, nickel and zinc is the construction materials of the distillation plants, while the source of lead and vanadium is the brackish water. Manganese and chromium concentrations are very low in all sources. No direct relationship between the metal concentration in the seawater and the distillate could be deduced.
3

Análisis y evaluación de la calidad del agua potable para la ciudad de Antofagasta bajo el contexto del suministro de agua desalada

Zúñiga Copano, Maximiliano January 2018 (has links)
Memoria para optar al título de Geógrafo / La presente investigación evalúa la calidad del agua potable para la ciudad de Antofagasta, Región de Antofagasta durante el periodo 2007 – 2016, en el contexto del suministro de distintos tipos de agua potable para la ciudad (desalada, de cordillera o una mezcla de ambas), en específico el suministro de agua potable desalada. Para esto se analizaron los datos de muestras para el periodo de estudio a través de la normativa chilena y fueron evaluados a partir de un índice global de calidad de agua potable. Además, se determinó la percepción de la población entorno a los distintos tipos agua potable de Antofagasta como herramienta complementaria a la evaluación de la calidad. Los resultados obtenidos revelaron que durante el periodo de estudio la calidad del agua potable para Antofagasta se encontró entre los márgenes aceptables de la normativa chilena y no presentó significativas diferencias a partir de los distintos tipos de agua, ya que cumple la normativa a grandes rasgos y presenta una cantidad menor de incumplimientos, pero presenta deficiencias en cuanto a los parámetros organolépticos (olor, sabor, color), lo cual se ve reflejado notoriamente en la percepción de los consumidores, además, se mantienen importantes interrogantes en cuanto a la capacidad de la normativa chilena de evaluar el agua potable desalada para la ciudad de Antofagasta, particularmente desde el contexto de salud de sus ciudadanos. / The present investigation evaluates the drinking water quality for the city of Antofagasta, region of Antofagasta during the period 2007 – 2016, under the context of different types of drinking water supplies, (desalinated, mountain or a mixture) specifically the desalinated drinking water. Water quality data for the study period was analyzed according to the Chilean drinking water guidelines, and then evaluated through a global drinking water quality index. The public perception to the different water supplies was also determined as a complementary tool for measuring water quality. The results showed that during the study period the drinking water quality for Antofagasta was acceptable in terms of the guidelines, because it did not manifest large differences regarding the types of water and had a few minor breaches. Yet it still showed deficiencies regarding organoleptic parameters (odor, taste, color), which was heavily reflected on consumers perception. Nonetheless, important questions remains regarding the capacity for the Chilean guidelines to evaluate desalinated water as drinking water for the city of Antofagasta, particularly from the city’s citizens context of health.
4

Sistema de captaÃÃo de energia solar para uma torre de dessalinizaÃÃo tÃrmica com recuperaÃÃo de calor / System of captation of solar energy for a tower of thermal dessalinizaÃÃo with heat recovery

RÃgio Davis Barros Alves 02 September 2009 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / This dissertation presents the experimental result of a system to absorb solar energy to heat up a desalination tower with heat recovery mechanism and a change made in the heated water distribution at the heat storage tank. The system to absorb solar energy consists of solar thermal flat plate collectors for high temperatures and it responsible for the conversion of solar radiation in thermal energy to heat up the water to be desalinated. The change made in the storage tank consists of the installation of a stainless steel pipe with holes equally spaced and arrangement to allow a better distribution of the hot water from the solar collectors in the heat storage tank. The desalination unit has two components: two high temperatures solar collectors and a desalination tower with six stages. In its operation, water is heated in the solar collectors and moves by natural convection to the storage tank, to the bottom of the tower. In the tank, the water transfers heat to the salty water in the first stage of the tower. This heated water transfer heat by evaporation, convection and radiation to the second stage and part of its energy is lost to the ambient. The condensed vapor on the walls of the stages flows down by gravity to be collected in a reservoir installed under the desalination tower. The heat received by the second stage is used to heat up the ater in this stage and the process is repeated in all stages. The performance of the desalination unit was satisfactory. The temperature in the storage tank reached values near 85ÂC and the water temperatures at the outlet of the solar collector were near 100ÂC. The daily production was 31 liters of desalinated water and the GOR-value (gain output ratio) was 1,54
5

Hälsorisker och kostnader i samband med avsaltat dricksvatten

Rahmani, Virginia January 2022 (has links)
I takt med att vattenbristen ökar har flera länder börjat använda avsaltning, en innovation som framställer rent men mineralfattigt vatten, för att möta vattenbehoven. Detta kandidatarbete ämnar att bidra med vidare kunskap kring avsaltat dricksvatten med bakgrund till tidigare forksning. Detta görs med hänsyn till tre ämnesområden där frågeställningarna är följande:  Vilka är de fundamentala processerna vid framställning av avsaltat dricksvatten? Vad finns det för hälsorisker med regelbunden konsumtion av avsaltat dricksvatten?  Hur bidrar olika faktorer till att kostnader i samband med avsaltat dricksvatten ökar och/eller minskar?  Denna studie fann att allt avsaltat dricksvatten går igenom tre grundläggande processer; förbehandling, avsaltning och remineralisering. Hälsoriskerna i samband med regelbunden konsumtion av avsaltat dricksvatten var; elektrolytavvikelse som kan leda till t.ex. cancer, 6 % större risk för ischemisk hjärtsjukdom, sköldkörtelproblem och ökad benskörhet. De olika faktorerna som bidrar till att kostnader i samband med avsaltat dricskvatten ökar och/eller minskar är:  Teknologins utveckling (Kostnader har minskat)  Bättre membranfilter (Kostnader har minskat)  Saltlaksavfall miljöpåverkan (Svårt att avgöra kostnder för)  Hälsopåverkan (Kostnader har ökat)  Val av vattenkälla (Påverkar kostnader för avsaltning)  Val av avsaltningsmetod (Påverkar kostnad för avsaltning)  Val av re-mineralisering (Påverkar kostnad för avsaltning)  Anläggningens storlek/kapacitet (Påverkar kostnad för avsaltning)  Val av energikällor (Påverkar kostnad för avsaltning)  Användandet av ERD (Kostnader har minskat)  Eftersom produktionen och konsumtionen av avsaltat dricksvatten förutspås öka bör myndigheter, såsom WHO, införa riktlinjer specifikt för avsaltat dricksvatten och dess mineralinnehåll. Dessutom har denna litteraturstudie kommit fram till slutsatsen att hälso- och miljöaspekter bör sammanvävas på ett bättre sätt med det avsalttade dricksvattnet. / As water scarcity increases, several countries have turned to the use of desalination, an innovation that produces clean but mineral-poor water in order to satisfy the water demands. This bachelor’s thesis aims to provide the reader with further knowledge about desalinated drinking water with background to previous research. This is done with regard to three questions:  What are the fundamental processes in the production of desalinated drinking water?  What are the health risks of regular consumption of desalinated drinking water?  How do various factors contribute to costs increasing and/or decreasing in relation to desalinated drinking water?  This study found that all desalinated drinking water goes throught three fundamental processes; pre-treament, desalination and remineralization. The healthrisks found in realtion to regular consumtion of desalinated drinking water was; electrolyte deviation which can lead to e.g. cancer, a 6% increase of iscehmic heart disease, poor thyroid condition and increased osteoporisis. The different factors that contribute to the costs of desalination increasing and/or decreasing are:  Technology development (costs have decreased) Better membrane filter (costs have decreased) Saline waste environmental impact (difficult to determine costs for) Health impact (costs have increased) Choice of water source (affects cost of desalination) Choice of desalination method (affects cost of desalination Choice of re-mineralization (affects cost of desalination) Plant size / capacity (affects desalination cost) Choice of energy sources (affects cost of desalination) Use of ERD (costs have decreased)  In addition as the production and consumtion of desalinated drinking water is predicted to increase, authorities, such as the WHO, should introduce guidelines specifically for desalinated drinking water and its mineral content. Furthermore, this literature study has come to the conclussion that health and enviorment components should be better interwoven with the production of desalinated drinking water.
6

Post Treatment Alternatives For Stabilizing Desalinated Water

Douglas, Susaye 01 January 2009 (has links)
The use of brackish water and seawater desalination for augmenting potable water supplies has focused primarily on pre-treatment, process optimization, energy efficiency, and concentrate management. Much less has been documented regarding the impact of post-treatment requirements with respect to distribution system. The goals of this study were to review current literature on post-treatment of permeate water, use survey questionnaires to gather information on post-treatment water quality characteristics, gather operation information, review general capital and maintenance cost, and identify appropriate "lessons learned" with regards to post-treatment from water purveyors participating in the Project. A workshop was organized where experts from across the United States, Europe and the Caribbean active in brackish and seawater desalination, gathered to share technical knowledge regarding post-treatment stabilization, identify solutions for utilities experiencing problems with post-treatment, note lessons learned, and develop desalination water post-treatment guidelines. In addition, based on initial workshop discussions, the iodide content of reverse osmosis and nanofiltration permeate from two seawater desalination facilities was determined. The literature review identified that stabilization and disinfection are required desalination post-treatment processes, and typically are considerations when considering 1) blending, 2) re-mineralization, 3) disinfection, and 4) materials used for storage and transport of product water. Addition of chemicals can effectively achieve post-treatment goals although considerations relating to the quality of the chemical, dosage rates, and possible chemical reactions, such as possible formation of disinfection by-products, should be monitored and studied. The survey gathered information on brackish water and seawater desalination facilities with specific regards to their post-treatment operations. The information obtained was divided into seven sections 1) general desalination facility information, 2) plant characteristics with schematics, 3) post-treatment water quality, 4) permeate, blend, and point of entry quality, 5) post-treatment operation, 6) operation and maintenance costs, 7) and lessons learned. A major consideration obtained from the survey was that facilities should conduct post-treatment pilot studies in order to identify operational problems that may impact distributions systems prior to designing the plant. Effective design and regulation considerations will limit issues with permitting for the facility. The expert workshop identified fourteen priority issues pertaining to post-treatment. Priority issues were relating to post-treatment stabilization of permeate water, corrosion control, disinfection and the challenges relating to disinfection by-product (DBP) formation, water quality goals, blending, and the importance of informing the general public. For each priority issues guidelines/recommendations were developed for how facilities can effectively manage such issues if they arise. One of the key priorities identified in the workshop was related to blending of permeate and formation of DBPs. However, it was identified in the workshop that the impact of iodide on iodinated-DBP formation was unknown. Consequently, screening evaluations using a laboratory catalytic reduction method to determine iodide concentrations in the permeate of two of the workshop participants: Tampa Bay and Long Beach seawater desalination facilities. It was found that the permeate did contain iodide, although at levels near the detection limit of the analytical method (8 [micro]g/L).

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