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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.
21

IWESS, an integrated water, energy and sanitation solution : A holistic approach to reach sustainability trough organic waste management for the Lake Victoria Basin, Kenya

Martinsson, Erik, Martinsson, Emil, Säf, Sören January 2008 (has links)
The process of allocating necessary resources like clean water, fuel/energy and food have resulted in an unsustainable use of natural resources causing problems with Soil erosion, soil fertility, desertification, deforestation, eutrophication and global warming. The purpose of this study was to gain information on the functional design of a waste management system enabling the organic components of domestic waste to be processed as useful resources while at the same time allow them to be re-circulated. The main part of this study was carried out at the Kendu SDA Hospital in the Rachyonyo district in western Kenya. For the case of this study two main objectives where chosen. The first was to develop a principal technological solution using three classed “appropriate technologies” found suitable for the purpose namely biogas, ecological water treatment systems and slow sand filtration. The second was to further analyse each included technology to further develop their potential to fit the concept. Results from the pilot facilities where then to be retrieved from the actual component selection and construction process itself, with performance analysis left for future studies. The main purpose of the biogas system study has been to evaluate the original ideas of overall concept, details, materials and construction methods. The 1 m3 biogas system has improved significantly during the development process and is today not far from an implementation, i.e. construction on a slightly larger scale. The biogas system developed during the project has proven to have potential for digestion of both latrine and kitchen waste. Using the two as fuel for the process does not only remove a problem – it grants several benefits. The ecological waste water treatment system main objective was to design and construct a pilot SSF-wetland. Results show that the construction process for smaller scaled SSF systems is simple and does not require trained personnel or specialized equipment and that significant cost reduction can be made by using locally available materials. The slow sand filtration sub system concept is called PT SCX and though still in the stage of development proved to have great potential concerning both efficiency and sustainability. The PT SCX comprises the advantages of slow sand filtration with further development of individual system solutions. It was adapted to enable both integration to the IWESS solution and stand alone installations purifying even highly turbid surface water sources to drinking water quality. The result from the study confirms the suitability of the three included technologies, ecological waste water treatment, biogas and slow sand filtration to work in an integrated system called IWESS- Integrated Water Energy and Sanitation Solution. The combined subsystems can together with source separated sewage offer full resource recovery enabling recirculation of both nutrients and water. In addition the system can be designed as a net producer of renewable and emission free energy.
22

IWESS, an integrated water, energy and sanitation solution : A holistic approach to reach sustainability trough organic waste management for the Lake Victoria Basin, Kenya

Martinsson, Erik, Martinsson, Emil, Säf, Sören January 2008 (has links)
<p>The process of allocating necessary resources like clean water, fuel/energy and food have resulted in an unsustainable use of natural resources causing problems with Soil erosion, soil fertility, desertification, deforestation, eutrophication and global warming. The purpose of this study was to gain information on the functional design of a waste management system enabling the organic components of domestic waste to be processed as useful resources while at the same time allow them to be re-circulated. The main part of this study was carried out at the Kendu SDA Hospital in the Rachyonyo district in western Kenya. For the case of this study two main objectives where chosen. The first was to develop a principal technological solution using three classed “appropriate technologies” found suitable for the purpose namely biogas, ecological water treatment systems and slow sand filtration. The second was to further analyse each included technology to further develop their potential to fit the concept. Results from the pilot facilities where then to be retrieved from the actual component selection and construction process itself, with performance analysis left for future studies.</p><p>The main purpose of the biogas system study has been to evaluate the original ideas of overall concept, details, materials and construction methods. The 1 m3 biogas system has improved significantly during the development process and is today not far from an implementation, i.e. construction on a slightly larger scale. The biogas system developed during the project has proven to have potential for digestion of both latrine and kitchen waste. Using the two as fuel for the process does not only remove a problem – it grants several benefits.</p><p>The ecological waste water treatment system main objective was to design and construct a pilot SSF-wetland. Results show that the construction process for smaller scaled SSF systems is simple and does not require trained personnel or specialized equipment and that significant cost reduction can be made by using locally available materials.</p><p>The slow sand filtration sub system concept is called PT SCX and though still in the stage of development proved to have great potential concerning both efficiency and sustainability. The PT SCX comprises the advantages of slow sand filtration with further development of individual system solutions. It was adapted to enable both integration to the IWESS solution and stand alone installations purifying even highly turbid surface water sources to drinking water quality.</p><p>The result from the study confirms the suitability of the three included technologies, ecological waste water treatment, biogas and slow sand filtration to work in an integrated system called IWESS- Integrated Water Energy and Sanitation Solution. The combined subsystems can together with source separated sewage offer full resource recovery enabling recirculation of both nutrients and water. In addition the system can be designed as a net producer of renewable and emission free energy.</p>
23

Sistema de filtração lenta no tratamento de percolado do aterro sanitario de Limeira-SP / Slow sand filter in the treatment of leachate of the sanitary landfill of Limeira -SP

Pelegrini, Nubia Natalia de Brito 17 February 2006 (has links)
Orientador: Jose Euclides Stipp Paterniani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-06T12:32:37Z (GMT). No. of bitstreams: 1 Pelegrini_NubiaNataliadeBrito_M.pdf: 1010430 bytes, checksum: 1a5af5bc021dbf527427add6944a6e6d (MD5) Previous issue date: 2006 / Resumo: A disposição final de resíduos sólidos é uma prática que ainda traz sérios impactos ao meio ambiente. Nos aterros sanitários, os resíduos passam por processos físicos, químicos e biológicos de decomposição, gerando uma fração gasosa (composta principalmente por gases dióxido de carbono e metano) e uma fase líquida conhecida como chorume (ou percolado de aterro sanitário). O chorume de lixo é um líquido com elevado potencial poluente, os métodos convencionais utilizados em seu tratamento têm descartado-o com intensa coloração e alta toxicidade. Este trabalho teve como objetivo implantar em escala piloto um sistema de filtração lenta precedido de uma pré-filtração, apenas em manta sintética não tecida, para o tratamento de chorume de lixo ¿in natura¿, proveniente do aterro sanitário da cidade de Limeira-SP. O filtro lento foi constituído por um tanque cilíndrico de plástico tendo como meio filtrante areia e mantas sintéticas não tecidas. A taxa de filtração adotada durante os experimentos foi de 3 m3/m2.dia. O sistema de tratamento em estudo apresentou reduções consideráveis dos valores de alguns parâmetros de controle ambiental indicando a possibilidade do uso da filtração lenta para remediação de águas residuárias. As principais reduções obtidas referem-se a 40% de turbidez, 21% da coloração, 35% de dureza, 35% de carbono orgânico total (TOC) e reduções consideráveis de metais pesados (60% de cádmio, 30% de chumbo, 25% de cobre e 30% de cromo). Com relação à reutilização do chorume tratado em atividades agrícolas ainda são necessárias maiores reduções dos valores de parâmetros analíticos através da complementação com outras tecnologias de tratamento / Abstract: The final disposition of solids residues is a practice that still brings serious impacts to the environment. In sanitary landfill, the residues goes through physical, chemical and biological decomposition processes, generating into a gas phase (mainly composed by CH4 and CO2) and a liquid phase known as leachate. The waste leachate is a liquid with high pollutant potential. The conventional methods used in the treatment this residue have discarded him with intense coloration and high toxicity. This work had as objective implant in pilot scale a system of slow sand filtration preceded of a pré-filtration, only in non-woven synthetic fabrics, for the waste leachate treatment in natura, originating from the sanitary landfill of the city of Limeira-SP. The slow sand filter is constituted by a plastic cylindrical tank, sands and non-woven synthetic fabrics. The filtration rate adopted during the experiments it was of 3 m3/m2.dia. The treatment system in study presented considerable reductions of some values of environmental parameters control indicating the possibility of the use of the slow filtration for remediação of wastewaters. The main obtained reductions were 40% of turbidity, 21% of color, 35% of hardness, 35% of total organic carbon (TOC) and reductions considerably of heavy metals (60% of cadmium, 30% of lead, 25% of cupper and 30% of chrome). For the reuse of the treated leachate in agricultural activities are necessary larger reductions of some values of analytic parameters through the complementation with other treatment technologies. eywords: Landfill Leachate, Sanitary Landfill, Slow Sand Filtration, Reuse / Mestrado / Agua e Solo / Mestre em Engenharia Agrícola
24

Kapacitetsminskning hos långsamfiltren vid Lovö och Norsborgs vattenverk : Studie av påverkande faktorer samt åtgärdsförslag / Reduced slow sand filtration capacity at the water treatment plants at Lovö and Norsborg : Reasons and ways on increasing the capacity

Mellander, Mattis January 2015 (has links)
Invånarantalet i Stockholm ökar och därmed också efterfrågan på dricksvatten. Stockholm Vatten VA AB fastslog i sin senaste prognos att kapaciteten hos deras vattenverk i Norsborg och på Lovö kommer att vara otillräcklig inom femton år och därmed måste ökas. Båda vattenverken tar vatten från Mälaren och renar detta genom flockning, sedimentering, snabbfiltrering, långsamfiltrering, UV-bestrålning samt tillsats av kloramin. Baserat på de senaste årens drifterfarenheter har långsamfiltrens kapacitet skrivits ned och är ett begränsande produktionssteg på båda verken. Detta examensarbete syftade till att fastställa orsakerna till kapacitetsminskningen och föreslå åtgärder. Undersökningen begränsades till Lovö vattenverk, men resultaten anses relevanta även för Norsborgs vattenverk.   De senaste åren har långsamsandfiltrens drifttid mellan rensningar minskat och tryckfallet i genomsnitt ökat. Här sågs att tryckfallet direkt efter rensning var högre i den undersökta periodens slut än under periodens början. Då filtrens belastning undersöktes konstaterades att filtreringshastigheten inte ökat och vattenkvaliteten inte försämrats. Utifrån detta drogs slutsatsen att kapacitetsminskningen inte berodde på ökad belastning.    Med hjälp av rör satta i filtersanden kunde tryckfallets fördelning över filterbäddens djup undersökas. I två av de undersökta filtren sågs ett kraftigt tryckfall i filtrens undre del. Då provgropar grävdes i filtren sågs ett tydligt gråaktigt lager vid den nivå där tryckfallet skett. Analyser av sandprover från filtren tydde på att en ackumulering av finkorniga sandpartiklar och organiskt material samt en lågporositet, gav det gråa lagret en låg mättad hydraulisk konduktivitet. Ackumuleringen av finkorniga sandpartiklar skulle kunna bero på att finkornigt material lyfts från filtrens hörn, där sandlagret är tunnare, och fördelas över resterande delar av filtret vid återfyllnad efter rensning.   Mätningar av porositet visade att filterbädden kompakteras då det belastas av de fordon som används vid rensning. Resultaten tyder dock på att packningens utbredning och omfattning är sådan att den inte har någon större effekt på tryckfallet i filtret. / Stockholm is growing and with it the demand for drinking water. To meet the demand the capacity of the two water treatment plants in Norsborg and at Lovö must be increased. Both plants use water from the lake Mälaren which is treated using flocculation, sedimentation, rapid filtration, slow sand filtration, UV-light and the addition of chloramine. The estimated capacity of the slow sand filters has decreased at both plants during the last few years and is limiting the total production capacity. This study aims to find the cause of the capacity decrease and make suggestions for how the capacity could be increased. Only the water treatment plant at Lovö was examined in this study, but the results are considered to be relevant for the water treatment plant in Norsborg as well.   During recent years the runtime of the filters has been decreasing and the overall loss of hydraulic head has increased. In several filters it was noted that the hydraulic head loss after filter cleaning had increased over time. Filter load was examined during the period in which the loss in capacity took place. Neither had the filtration rate increased nor had the water quality decreased. A higher load could therefore be ruled out as the source of the capacity loss.   Hydraulic head loss distribution over the depth of the filter beds was examined using steel pipes placed in the filter bed at different depths. In two filters a large hydraulic head loss was found at a narrow section in the bottom of the filters. Holes were dug in the filter beds, from which a distinct grey layer could be observed. Sand analyses showed that an accumulation of fine sand particles and organic matter combined with a low porosity could have been what caused the large hydraulic head loss in the layer. This material could have originated from the corners of the filters. During filter refill, fine material was observed being suspended from the corners and spread across the filter.   Measurements of sand porosity suggested that the filter bed is compacted by the machines used to clean the filters. This however seemed to have a negligible effect on the hydraulic head loss in the filters.

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