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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

Estimation of the possible waste reduction by the implementation of SODIS : A numerical-, experimental- and social study executed in Ghana

Arvidsson, Daniel January 2013 (has links)
Lack of safe drinking water is one of the biggest humanitarian problems in the world today. Over one billion people in developing countries have no access to good quality drinking water, and subsequently, diarrhoea caused by unclean water leads to 1.8 million deaths of children under the age of five. That corresponds to 90 per cent of all deaths among children in that age group. However, by improving water and sanitation management, one tenth of all worldwide cases of disease can be prevented. In relation to this, the United Nations has launched the seventh millennium goal, which is to half the proportion of people lacking access to safe drinking water by year 2015 (compared with the proportion of year 2000). Therefore, it is important to both improve and develop water treatment techniques in order to achieve a sustainable development, especially in the third world.   Kofi Ansah and Edumafa are two villages on the Ghanaian countryside. Here, as in the rest of Ghana, it is common to drink water from throwaway plastic containers. This is because the water quality is poor in the stationary water sources such as tanks and wells etc. The plastic containers contribute to a big waste problem and it´s therefore desirable to improve the water quality in stationary water sources in order to reduce the waste problem that now is occurring.   Solar Disinfection, or SODIS, is a water treatment technique that is based on solar radiation. Water containers (usually PET bottles) are filled with water and then exposed to the sun for about six hours. The germicidal effect can be derived to thermal heating in combination with the sun’s ultraviolet radiation. The technique is suitable in the third world since the treatment procedure is both simple and inexpensive. The purpose of this study was to estimate the possible waste reduction regarding the small plastic containers by the implementation of SODIS as a water treatment technique, and evaluate if SODIS is an adequate way to improve the quality of water collected from stationary water distribution systems in Ghana.   The study has shown that SODIS is an adequate method for producing low health risk water at a household level in Ghana. A solar exposure of six hours is enough to reach a safe bacterial content within the treated water. It is also clear that SODIS could reduce the present waste problem regarding the throwaway plastic containers by more than 1600 plastic bags per person and year, and that the Ghanaians attitude to start performing SODIS is positive.   Further work should be aimed at implementing SODIS as a water treatment technique by teaching the Ghanaian people, especially in the rural areas, the importance of water and sanitation issues. The implementation of SODIS is a long term project that cannot be accomplished singlehandedly. It can be achieved by instructing certain people in the villages as to how the procedure is done. For this to be effective, these individuals should preferably be well educated and speak both English and the local language. These people can in turn educate and instruct the other villagers in how SODIS is executed and by doing so complete and secure a sustainable use of the technique. / Bristen på rent dricksvatten är ett av de största humanitära problemen världen står inför idag. Över en miljard människor i utvecklingsländer saknar tillgång till rent dricksvatten, och diarré orsakat av orent vatten leder varje år till 1,8 miljoner barn under fem års död. Det motsvarar 90 procent av alla dödsfall bland barn i den åldersgruppen. Vidare kan 10 procent av världens alla sjukdomsfall förebyggas genom förbättrad vatten- och sanitetshantering. I tillägg till detta har Förenta Nationerna lanserat det sjunde millenniemålet som är att halvera antalet människor utan tillgång till rent dricksvatten till år 2015 (jämfört med nivåerna år 2000). Det råder därför ingen tvekan om att det är viktigt att både förbättra och utveckla vattenreningstekniker, särskilt i tredje världen.   Kofi Ansah och Edumafa är två byar på den ghananska landsbygden. Där är det, som i resten av landet, vanligt att dricka sitt vatten ur engångsplastpåsar. Detta eftersom vattenkvalitén är undermålig i stationära vattenkällor, såsom tankar och brunnar etc. Plastpåsarna bidrar till ett omfattande avfallsproblem och det vore därför önskvärt att förbättra kvalitén hos vattnet från stationära källor för att på så vis minska plastanvändningen.   Solar Disinfection, eller SODIS, är en vattenreningsteknik som baseras på solstrålning. Vattenbehållare (vanligtvis PET-flaskor) fylls med vatten och exponeras sedan för solen i ungefär sex timmar. Den desinficerande effekten kan förklaras med termisk rening i kombination med solens ultravioletta strålning. Tekniken är lämplig i utvecklingsländer eftersom den är både enkel och billig att utföra. Studiens syfte var att uppskatta den potentiella avfallsreduceringen som skulle uppstå om man skulle implementera SODIS, samt att undersöka om SODIS är en lämplig vattenreningsteknik för att förbättra vattenkvalitén från stationära system i Ghana.   Studien har visat att SODIS är en lämplig metod för att producera vatten med en låg hälsorisk för små hushåll Ghana. Sex timmars solexponering är tillräckligt för att nå en säker bakterienivå hos det behandlade vattnet. Det är också tydligt att SODIS kan reducera avfallsproblemet gällande plastpåsarna med mer än 1600 plastpåsar per person och år samt att ghananernas inställning till SODIS är positiv.   Framtida arbete bör vara inriktat på att implementera SODIS genom att upplysa den ghananska befolkningen, särskilt på landsbygden, vikten av vatten- och sanitetsfrågor. En SODIS-implementering är ett långsiktigt projekt och kan inte åstadkommas ensamt. Det kan uppnås genom att instruera vissa människor i byarna hur tekniken går till. Dessa individer bör vara välutbildade och dessutom tala både engelska och det lokala språket. Dessa personer kan sedan lära och instruera övriga bybor hur SODIS går till och på så sätt fullborda och säkerställa ett hållbart användande av tekniken.
2

A Practical Mechanism for Ethical Risk Assessment-A SoDIS Inspection

Gotterbarn, Don, Clear, Tony, Kwan, Choon T. 26 January 2009 (has links)
No description available.
3

The Uniqueness of Software Errors and Their Impact on Global Policy

Gotterbarn, Donald 01 January 1998 (has links)
The types of errors that emerge in the development and maintenance of sofhvare are essentially different from the types of errors that emerge in the development and maintenance of engineered hardware products. There is a set of standard responses to actual and potential hardware errors, including: engineering ethics codes, engineering practices, corporate policies and laws. The essential characteristics of software errors require new ethical, policy, and legal approaches to the development ofsoftvare in the global arena.
4

Utilização da técnica de desinfecção solar de água para inativação de Escherichia coli e Pseudomonas aeruginosa na região centro-oeste do Brasil

Brum, Bruno Ramos 24 February 2015 (has links)
Submitted by Jordan (jordanbiblio@gmail.com) on 2017-03-14T13:46:02Z No. of bitstreams: 1 DISS_2015_Bruno Ramos Brum.pdf: 1838440 bytes, checksum: 2c916a0f76662b4c7a8adc7f0fa75ba7 (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2017-03-14T16:06:01Z (GMT) No. of bitstreams: 1 DISS_2015_Bruno Ramos Brum.pdf: 1838440 bytes, checksum: 2c916a0f76662b4c7a8adc7f0fa75ba7 (MD5) / Made available in DSpace on 2017-03-14T16:06:01Z (GMT). No. of bitstreams: 1 DISS_2015_Bruno Ramos Brum.pdf: 1838440 bytes, checksum: 2c916a0f76662b4c7a8adc7f0fa75ba7 (MD5) Previous issue date: 2015-02-24 / O consumo de água contaminada por agentes microbianos patogênicos é responsável pela morte de dois milhões de pessoas todo o ano no mundo. Diante dessa problemática a desinfecção da água pela radiação solar é uma solução simples, de baixo custo e eficaz, que é praticada a nível doméstico, em muitos países em desenvolvimento. O objetivo deste estudo foi avaliar o tempo de decaimento bacteriano e a eficiência desta técnica na região Centro-Oeste do Brasil, com base na inativação de duas espécies bacterianas utilizando quatro sistemas diferentes para a desinfecção solar. Primeiramente se construiu três concentradores revestidos com espelho, lata de alumínio, tetra pak e ainda um sistema sem concentrador. Em seguida foi coletada água de poços rasos de uma comunidade localizada em Cuiabá, MT, que apresentaram contaminação microbiológica por coliformes totais e Escherichia coli para averiguar a eficácia da técnica, com água contaminada naturalmente. Depois deste feito realizou-se a contaminação em laboratório de água de poço estéril com cepas padrão de Escherichia coli, Pseudomonas aeruginosa e se aplicou a técnica, dessa vez com água contaminada de forma controlada. Quando se tinha boas condições climáticas e tempo aberto todos os sistemas utilizando água contaminada em laboratório apresentaram 100% de eficiência, o que já não ocorreu com água dos poços contaminados, onde a inativação dos microrganismos nem sempre atingiu uma boa desinfecção. A análise de variância da temperatura e a modelagem matemática mostraram que existe uma variação de temperatura significativa quando comparados os quatro tipos de sistemas utilizados, fator que não interfere na eficiência da desinfecção, visto que todos os tratamentos obtiveram 100% de eficácia na inativação dos microrganismos no experimento controlado. Os resultados sugerem que na região de estudo apenas a exposição de garrafas ao sol já é eficiente, além de mais barato quando se tem boas condições climáticas (tempo limpo). / The consumption of water contaminated by pathogenic microbial agents are responsible for the deaths of two million people every year worldwide. Faced with this problem the water disinfection by solar radiation is a simple, inexpensive and effective, which is practiced at the household level in many developing countries. The objective of this study was to evaluate the bacterial decay time and the efficiency of this technique in the Midwest region of Brazil, based on the inactivation of two bacterial species using four different systems for solar disinfection. First it built three hubs coated with mirror, aluminum can, tetra pak and still a no hub system. Then water was collected from shallow wells of a community located in Cuiabá, MT, who had microbiological contamination for total coliforms and Escherichia coli to determine the technical efficiency with contaminated water course. After this done took place contamination in sterile water well with standard laboratory strains of Escherichia coli, Pseudomonas aeruginosa and applied the technique, this time with contaminated water in a controlled manner. When it had good weather and open time all systems using water contaminated lab 100%, which no longer occurred with water from contaminated wells, where the inactivation of microorganisms is not always achieved a good disinfection. The temperature variance analysis and mathematical modeling showed that there is a significant temperature variation when comparing the four types of used systems, a factor that does not interfere with disinfection efficiency, as all treatments achieved 100% effective in the inactivation of microorganisms . The results suggest that the study area only to exposure to the sun bottles are already efficient, and cheaper when you have good weather conditions (clear weather).
5

Avaliação do sistema de tratamento de esgoto doméstico pelo processo de escoamento superficial, pós UASB, da remoção de N e P e da desinfecção via SODIS / Evaluation of a UASB wastewater system treatment, followed by an overland system in the removal of N and P and the solar radiation disinfection system SODIS

Cabanellas, Cláudia Figueiredo Garrido 28 February 2013 (has links)
Made available in DSpace on 2015-03-26T12:31:28Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2840967 bytes, checksum: 92d732eeb2095a64c55f199a2657bd40 (MD5) Previous issue date: 2013-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study was to evaluate a wastewater treatment system consisting of a primary system, followed by UASB and an overland flow system cultivated with grass Tifton 85, during one year; to analyze the balance of nutrients in the overland flow system and to evaluate the performance of a solar radiation wastewater disinfection system - SODIS. Every 30 to 35 days samples of the influent and the effluent of the UASB, the overland flow system, the grass, the soil, at the depths 0-15 cm and 15-30 cm, and the volatilized nitrogen were collected. It was found that the UASB efficiencies were: BOD 95 and 86%, COD 93 and 88%, NTK 40 and 31%, N-org 85% and 79%, total alkalinity of 193 and 202 mg.L-1, , sulfides 92% and 80%, and SS 97% and 91%, respectively, for the rain and te dry seasons. The overland flow system presented the following efficiencies: BOD 62 and 85%, COD 71 and 72%, ST 6 and 21%, Norg 14 and 35%, NTK 46 and 54%, N- NH3 48 and 21%, PT 46% and 46%, E. coli 1 log unit e 2 log unit, for the rain and the dry seasons, respectively. There was no movement of the elements studied along the first 30 cm of soil. The TKN reduced and the NO3 - increased along the ramp of the overland flow system. The nitrogen volatilization was 0,42% and 0,36%, for the rain and the dry seasons, respectively. There was a reduction of 55% of the Pt in the overland flow system, showing the capacity of Pt absorption for the grass. The grass protein ranged from 13 to 22%. The depths of 15, 20 and 25 cm were tested in the pilot solar radiation disinfection system (SODIS). The wastewater presented an average turbidity of 26 NTU, TSS of 23 mg / L, and 105 to 107 NMP/100ml of E. coli. In the rain season, with a 24 hours of exposure to solar radiation occurred a removal of approximately 4 log of E. coli, when the daily average solar radiation was 25 MJ/m2. In the dry season, after 24 hours of solar exposure approximately 2 log of E. coli was removed, for an average solar radiation of 10 MJ/m2. The E. Coli population reduction was higher for lower depths e the SODIS. The SODIS was not effective to remove the helminthes eggs. / O objetivo deste trabalho foi avaliar um sistema de tratamento de esgoto doméstico, constituído por sistema preliminar, seguido por reator UASB e rampa de escoamento superficial cultivada com gramínea Tifton 85, durante um ano; analisar o balanço de nutrientes na rampa de escoamento superficial e avaliar o desempenho do reator SODIS, para desinfecção do efluente do sistema. Foram coletadas amostras, a cada 30 a 35 dias, do afluente e efluentes do UASB e da rampa de escoamento superficial, da gramínea, do solo, nas profundidades 0-15 cm e 15-30 cm, e do nitrogênio volatilizado. No reator UASB as eficiências foram: DBO 95 e 86%, DQO 93 e 88%, NTK 40 e 31%, N-org de 85% e 79%, alcalinidade total 193 mg.L-1 e 202 mg.L-1, sulfetos 92% e 80%, SS 97% e 91%, respectivamente, para as estações chuvosa e seca. Na rampa de escoamento superficial, obtiveram-se eficiências de: DBO 62% e 85%, DQO 71% e 72%, ST 6% e 21%, N-org 14% e 35%, NTK 46% e 54%, N-NH3 48% e 21%, PT 46% e 46%, E. coli 1 unidade log e 2 unidades log, nas estações chuvosa e seca, respectivamente. Não foi observado deslocamento dos elementos analisados na camada de 0 a 30 cm do solo. Verificou-se redução do NTK e acréscimo do NO3 - ao longo da rampa. A volatilização de nitrogênio foi de 0,42 e 0,36%, nos período chuvoso e seco, respectivamente. Houve redução de 55% do Pt no efluente da rampa, demostrando a capacidade de remoção deste elemento pela gramínea. Os valores de proteína bruta na forrageira variaram de 13 a 22 %. Foram avaliadas as laminas de 15, 20 e 25 cm no sistema piloto (SODIS) instalado após o sistema de escoamento superficial, cujo afluente apresentava turbidez média de 26 NTU, SST de 23 mgL-1 e concentrações de E. coli de 105 e 107 NMP 100ml-1. Observou-se que, na estação chuvosa, nas 24 horas de exposição à radiação solar (25 MJm-2) ocorreu remoção de aproximadamente 4 Unidades logarítmicas de E. coli e na estação seca 2 unidades logarítmicas de E. coli com 10 MJm-2 . A redução da população de E. coli é menor para maiores lâminas do efluente no SODIS. Não houve redução de ovos de helmintos no efluente da rampa após 24 h de exposição à radiação solar.
6

AvaliaÃÃo do Processo de DesinfecÃÃo Solar (SODIS) e de sua Viabilidade Social no Estado do Cearà / Solar Disinfection Evaluation and its Social Viability at State of CearÃ, Brazil

Marcio Pessoa Botto 14 August 2006 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Apesar da importÃncia do saneamento ambiental para o bem-estar do homem e para a conservaÃÃo dos recursos naturais, uma grande parcela da populaÃÃo mundial nÃo tem acesso aos serviÃos bÃsicos de saneamento. Uma tÃcnica caseira que vem sendo estudada e aplicada em paÃses em desenvolvimento, como uma tecnologia segura para o tratamento microbiolÃgico de Ãgua à a desinfecÃÃo solar, SODIS. Este mÃtodo utiliza apenas o sol e garrafas PET como insumo. Atualmente, cerca de um milhÃo de pessoas utiliza regularmente o SODIS em 20 diferentes paÃses. O presente estudo avaliou a eficiÃncia de inativaÃÃo de coliformes termotolerantes segundo o efeito da aerobiose, por meio da agitaÃÃo manual das garrafas e da utilizaÃÃo de diferentes superfÃcies de exposiÃÃo sob as condiÃÃes climÃticas do Estado do CearÃ, bem como a viabilidade social deste mÃtodo em quatro comunidades inseridas em cenÃrios distintos (rural, litorÃno e urbano). Para tanto, compararam-se amostras agitadas e nÃo agitadas, e amostras expostas sobre superfÃcies distintas: concreto pintado de branco, concreto pintado de preto, telha de barro, telha de amianto e bacias de alumÃnio. Para o estudo da viabilidade social, foram aplicados questionÃrios aos usuÃrios do mÃtodo e analisadas amostras da Ãgua bruta e tratada pelo mÃtodo SODIS. Verificou-se que apesar da agitaÃÃo aferir uma concentraÃÃo de 0,75mg/L a mais de OD nas amostras agitadas, esse efeito nÃo foi capaz de aumentar significativamente a eficiÃncia de inativaÃÃo para essas amostras. O decaimento mÃdio bacteriano das amostras agitadas foi 1,10 vezes maior comparado Ãs amostras nÃo agitadas. Os dados obtidos na etapa de superfÃcie indicaram que tambÃm nÃo hà diferenÃa significativa (teste T de Student, nivel de confianÃa 0,05) de inativaÃÃo em expor as garrafas sobre qualquer uma das superfÃcies pesquisadas. O decaimento mÃdio bacteriano foi de: 0,3049h-1, 0,2624h-1, 0,3152h-1, 0,2747h-1, 0,2874h-1, respectivamente, para as amostras sobre o concreto pintado de branco, concreto pintado de preto, telha de amianto, telha de barro e bacia de alumÃnio. A mÃxima temperatura da Ãgua foi de 44ÂC e ainda assim obteve-se mais de 99,99% de remoÃÃo de coliformes termotolerantes em todos os ensaios. Em 67% dos ensaios, o SODIS foi capaz de inativar completamente concentraÃÃes de coliformes termotolerantes acima de 105 NMP.100mL-1 durante as seis horas de exposiÃÃo. O estudo de campo mostrou que o SODIS melhorou a qualidade microbiolÃgica da Ãgua das quatro comunidades pesquisadas. No entanto, a permanÃncia e em alguns casos a proliferaÃÃo do indicador foi verificado quando os usuÃrios expuseram as garrafas em locais sombreados. O SODIS foi bem aceito nas comunidades rurais e litorÃneas, atingindo nÃveis de aceitaÃÃo acima de 45%, se comparado aos da comunidade urbana, com apenas 8%. AlÃm da grande aceitaÃÃo do mÃtodo, mais de 80% dos usuÃrios responderam que iriam continuar a usar o SODIS. / Despite the importance of sanitation for well-being of the mankind and the natural resources conservation, still today a large number of people do not have access to wastewater system neither to public water supply. One technique which has being studied and applied in developing countries as a safe household water treatment method is solar disinfection, SODIS. The only two elements demanded to this method are PET bottles and the sun. Nowadays, around one million people use SODIS regularly in 20 different countries. This study evaluated the feacal coliform bacteria inactivation efficiency according to the effect of bottlesâ agitation and the use of differents exposition surfaces under of State of Cearà climatic conditions, as well as SODIS social viability in four communities at distinct geographical location (peri-urban, rural and coastal). To achieve this, agitated and non-agitated samples and five diferrents surfaces: concrete spotted in white color, concrete spotted in black color, abobe roofing tile, asbestos roofing tile and aluminum basins were investigated. To evaluate social acceptability, questionnaires had been applied to all users SODIS and raw water and treated water by SODIS were analyzed. It was verified that despite the agitation surveying a concentration more than 0,75mg/L of OD in the agitated samples, this effect was not capable to increase significantly the inactivation efficiency in these samples. The mean decay constant for bacterial population in agitated bottles was found to be a factor of 1.10 higher than in non-agitated bottles. The surface investigation indicated that no significant difference (paired StudentÂs T-test at P=0,05 significance level of log10 transformed data) in inactivating feacal coliforms by exposing the bottles over the five surfaces examined were observed. The mean decay constant for bacterial population was: 0,3049h-1, 0,2624h-1, 0,3152h-1, 0,2747h-1, 0,2874h-1, respectively for the sample exposed over concrete spotted in white color, concrete spotted in black color, abobe roofing tile, asbestos roofing tile and aluminum basins. The maximum water temperature reached was 44ÂC and still thus, it was obtained reduction more than 99.99% of feacal coliforms. In 67% of the assays, SODIS was capable to completely inactivate concentrations of feacal coliforms above 105 NMP.100mL-1 within six hours of exposition. The field study had shown that SODIS improved the microbiological water quality in the four communities. However, the permanence and in some cases the increase of feacal coliforms was verified when the users exposed the bottles in shaded areas. SODIS was well received in rural and coastal communities reaching acceptance levels over than 45%, compared to urban community, with only 8%. Beyond the great acceptance of the method, over 80% of the users answered that they would continue to use SODIS.
7

Desinfecção solar da água: avaliação da técnica "SODIS" aplicada a águas de chuva, poço e manancial superficial, nas condições climáticas de verão na região de Porto Alegre, RS

Carvajal, Ruth Angelic Reyes January 2015 (has links)
SODIS (Solar Water Disinfection) é uma tecnologia simples para tratamento de água no pontode- uso, sendo uma alternativa importante para disponibilizar água em situações de emergência ou onde não há acesso à água potável. A ação concomitante entre a temperatura e a radiação ultra violeta do sol provoca a morte dos microorganismos presentes na água. Este estudo avaliou a eficiência de inativação de coliformes totais e Escherichia coli pela técnica SODIS para as águas de chuva (coletada em telhado), de poço freático e de manancial superficial (reservatório), sob as condições climáticas de verão de Porto Alegre, RS. Foram ainda, realizados ensaios para verificar se ocorreu o recrescimento dos microorganismos após 24 e 48 horas do término da exposição ao sol. Também foram determinadas as constantes de decaimento das bactérias utilizando a Lei de Chick para representar o declínio dos microorganismos. Os ensaios de SODIS foram realizados em batelada, utilizando garrafas PET transparentes de 1,5 L, expostas ao sol por um período de 6 h. O mesmo número de garrafas era mantido à sombra pelo mesmo período, como controle. As temperaturas do ar e da água e a radiação ultravioleta foram monitoradas ao longo dos ensaios. Os valores médios de remoção de concentrações de E. coli no SODIS nas amostras das águas analisadas variaram entre 98,8 a maior do que 99,99%; para coliformes totais as reduções médias nas amostras variaram entre 90,00 – 99,99%. Não houve recrescimento de microorganismos após 24 e 48 horas seguindo-se ao término da exposição solar. As constantes de decaimento para coliformes totais e E. coli foram, respectivamente, 0,2979 h-1 e 0,9397 h-1, confirmando as observações de que E. coli é mais sensível a desinfecção. Os coeficientes de determinação para a equação da Lei de Chick foram de 0,938 (E. coli) e 0,877 (coliformes totais). Os resultados da pesquisa indicam que as águas de chuva e de poço freático tratadas com SODIS atingiram os padrões microbiológicos recomendados pela Organização Mundial da Saúde, o que não ocorreu com as amostras de água do reservatório superficial estudado. / SODIS (Solar Water Disinfection) is a simple techhnology for point-of-use drinking water treatment, and can be used during emergencies or in sites without running water. The joint action of high temperature and ultraviolet radiation causes the die-off of microrganisms. This study evaluated the removal of total coliforms and Escherichia coli using SODIS to disinfect water from rain (collected in roofs), from well and from surface water (reservoir) under the climate conditions of Porto Alegre, RS. Essays were also conducted to see if bacteria regrowth occurred after 24 and 48 h after the end of the SODIS test. In addition, bacterial decay coefficients were calculated using the Chick´s Law as model. SODIS essays were performed in batch reactors using 1.5 L transparent PET bottles exposed to the sunlight for 6 h.The same number of bottles were kept in the shadow, as a control. Air and water temperatures and ultraviolet radiation were monitored hourly. E. coli mean removals in samples from the three sources of water varied between 98,8% to greater than 99,99%. The mean reductions for total coliforms varied between 90.0% to 99.99%. Microorganism regrowth was not observed after 24 and 48 h. Decay coefficients for coliforms and E. coli were, respectively, 0.2979 h-1 e 0.9397 h-1, confirming the observation that E. coli is more sensitive than total coliforms to SODIS. Coefficients of determination for Chick´s Law equation were 0.938 (E. coli) and 0.877 (total coliform). The results from this research indicate that water from rain and well , but not reservoir, achieved the World´s Health Organization drinking water guidelines for drinking water with low risk of disease acquisition.
8

The stakeholder value and pedagogical validity of industry certification

Hitchcock, Leo Unknown Date (has links)
In December 2004, at the SoDIS® (Software Development Impact Statements) symposium in Auckland, an industry certification as a method of credentialing teachers and analysis of SoDIS was mooted. SoDIS, a process of ethics-based risk assessment and analysis of downstream risk to project and software stakeholders, including the public, is currently in the process of progressing from prototype to commercial product. Certification was proposed to ensure the integrity of the process and the quality of service to stakeholders.Certification sponsored by industry, commercial organisation, or professional association (collectively referred to as industry certification, or certification) has been a form of credentialing for over half a century. Industry certification was adopted by the IT industry when Novell, Inc. began testing and certifying IT industry and IT network professionals in 1986 (Cosgrove, 2004; Novell, 1996). Global certification testing centres were established in 1990 by Drake International (now Thomson Prometric) (Foster, 2005).During the 1990s, industry certification became a veritable juggernaut: a "multi-billion dollar business" (Cosgrove, 2004, p. 486), an industry that has arisen in its own right (Adelman, 2000) and driven by several dynamics (Hitchcock, 2005). In 2000 there were over 300 discrete IT certifications with approximately 1.6 million individuals holding approximately 2.4 million IT certifications (Aldelman, 2000). The total number of available certifications is impossible to quantify (Knapp & Gallery, 2003). Many academic institutions both at tertiary and secondary level are integrating industry certification, especially IT certification, into their curricula.Is industry certification, however, a pedagogically robust form of credentialing? Does it have value to its stakeholders? Is it an appropriate form of credentialing for the SoDIS process? This research, using both Phenomenography and Interpretive Phenomenological Analysis (IPA) as a joint methodology, focuses on the experiences of actors with the phenomenon of industry certification and extracts both the essence of the understanding and perceptions of the value and validity of industry certification, and the essence of industry certification itself.Due to the vast amount of literature found describing industry actors' perceptions of and experiences within the phenomenon, the research is predominantly literature-based. Further data was collected from interviews with a small, purposive sample of industry certification holders and employers, with the research further informed by my own experiences within the domain which is the focus of the research. The methodology paradigm is interpretive: the research aims to interpret the social construction that is the phenomenon of industry certification.While this research does not attempt to single out specific industry certifications to determine their value or pedagogical robustness, the findings suggest that, in general, well designed and well administered certifications with integrity and rigour of assessment processes, are indeed pedagogically sound, with significant value. The research identifies both benefit and criticism elements of typical certifications, along with elements of the various certification programmes categorised into standard (typical), and more rigorous (less typical) certification programmes.The research develops and presents a paradigm for building an appropriate vendor specific or vendor neutral certification programme that is pedagogically sound with value for its stakeholders. The contrasts and complementary aspects of industry certification and academic qualifications are highlighted. It is therefore concluded, and supported by data from the interviews, that such a credential is indeed appropriate for teachers and analysts of SoDIS.
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Exploring Pretreatments for the Solar Water Disinfection (SODIS) Process

Hirtle, Lacey Elizabeth January 2008 (has links)
The use of sunlight for water disinfection has been practiced since ancient times. Only in the last three decades has solar disinfection become widely recognized as a viable means of providing safe drinking water to the disadvantaged portion of the world’s population. The World Health Organization estimates that 1.6 million people die every year because of waterborne diseases. <br/><br/> The Swiss Federal Institute of Environmental Science and Technology and their Department of Water and Sanitation in Developing Countries have been instrumental in propagating the solar water disinfection (SODIS) process in developing countries. The reason for this technology being widely used and accepted is its ease of use and effectiveness: water is placed in clear plastic bottles and exposed to direct sunlight for approximately six hours. The microorganisms in the water absorb the sunlight and it, in turn at sufficient UV dosages, causes mutations to their genetic material, inhibiting reproduction. Although some pathogens may still be viable they are no longer infective. The result is microbiologically safe water. <br/><br/> Research to date has explored everything from which colour and size the SODIS containers should be to whether adding catalysts to the water before exposure improves disinfection. Apart from a few studies that examined the effect of shaking the bottles (to entrain air) before exposure, there has been limited research on pretreatments for enhancing solar disinfection. <br/><br/> The focus of this project was to explore two pretreatments for SODIS and determine how they affect the efficiency of the process. The first stage was to examine one of the currently used pretreatments: cleaning the water containers before use. The second stage was to develop an accessible, low-cost filtration technique to remove particles from the water before exposure to sunlight. Particles in the water disperse the light and protect the microorganisms from being inactivated, so it is important to have as few particles as possible; the recommended upper limit is 30 NTU for solar disinfection. In many instances, surface water with high turbidity (greater than 200 NTU) serves as the only source for drinking water in developing areas. <br/><br/> The first series of experiments in the current research evaluated if cleaning the bottles was necessary and if so, which cleaning agents would be most effective and available. The agents selected were 70% isopropyl alcohol, a soap-water mixture, and lime juice. The experiments demonstrated that cleaning with 70% isopropyl alcohol did not affect the process in any way. Cleaning with the soap-water mixture did have a slightly negative effect on the process; there was substantial microbial recovery when bottles were kept in the dark overnight. In the case of the lime juice, it actually inhibited the disinfection process. It is necessary to remove any debris that might exist within the containers before using them, but using a chemical cleaning agent or mechanically scrubbing can decrease the amount of disinfection that occurs during SODIS. Thus, it is suggested that using a chemical pretreatment is not necessary and has the potential to inhibit disinfection, especially without proper training or technical knowledge. <br/><br/> The second series of experiments identified the optimal design for a low-cost roughing filter that could be used to remove particles from water before exposure to sunlight. The roughing filter that was built from the same plastic pop bottles used for solar disinfection, as well as gravel and sand. It was constructed with three centimetres of gravel on the bottom of the pop bottle and then 17 cm of coarse sand was added on top to make the total filter height 20 cm. A 0.6 mm hole was made at approximately 1.5 cm from the bottom of the bottle using a standard sewing needle. Each filter run consisted of 10 L of water at approximately 200 NTU. Experimental results indicated that 95% removal of turbidity could be achieved. These roughing filters can be constructed from readily available and affordable materials in developing countries and produce an effluent water quality of less than 30 NTU when initial turbidities are greater than 200 NTU. <br/><br/> Finally, the third series of experiments focused on testing the newly developed roughing filter in series with SODIS to evaluate the system as a whole. The results confirmed that using the roughing filter, as a pretreatment to SODIS, is a highly effective means of improving the disinfection potential of the process. These roughing filters produce an effluent water quality of less than 30 NTU, which is required for SODIS, making them a viable pretreatment for turbid water intended for SODIS use.
10

Exploring Pretreatments for the Solar Water Disinfection (SODIS) Process

Hirtle, Lacey Elizabeth January 2008 (has links)
The use of sunlight for water disinfection has been practiced since ancient times. Only in the last three decades has solar disinfection become widely recognized as a viable means of providing safe drinking water to the disadvantaged portion of the world’s population. The World Health Organization estimates that 1.6 million people die every year because of waterborne diseases. <br/><br/> The Swiss Federal Institute of Environmental Science and Technology and their Department of Water and Sanitation in Developing Countries have been instrumental in propagating the solar water disinfection (SODIS) process in developing countries. The reason for this technology being widely used and accepted is its ease of use and effectiveness: water is placed in clear plastic bottles and exposed to direct sunlight for approximately six hours. The microorganisms in the water absorb the sunlight and it, in turn at sufficient UV dosages, causes mutations to their genetic material, inhibiting reproduction. Although some pathogens may still be viable they are no longer infective. The result is microbiologically safe water. <br/><br/> Research to date has explored everything from which colour and size the SODIS containers should be to whether adding catalysts to the water before exposure improves disinfection. Apart from a few studies that examined the effect of shaking the bottles (to entrain air) before exposure, there has been limited research on pretreatments for enhancing solar disinfection. <br/><br/> The focus of this project was to explore two pretreatments for SODIS and determine how they affect the efficiency of the process. The first stage was to examine one of the currently used pretreatments: cleaning the water containers before use. The second stage was to develop an accessible, low-cost filtration technique to remove particles from the water before exposure to sunlight. Particles in the water disperse the light and protect the microorganisms from being inactivated, so it is important to have as few particles as possible; the recommended upper limit is 30 NTU for solar disinfection. In many instances, surface water with high turbidity (greater than 200 NTU) serves as the only source for drinking water in developing areas. <br/><br/> The first series of experiments in the current research evaluated if cleaning the bottles was necessary and if so, which cleaning agents would be most effective and available. The agents selected were 70% isopropyl alcohol, a soap-water mixture, and lime juice. The experiments demonstrated that cleaning with 70% isopropyl alcohol did not affect the process in any way. Cleaning with the soap-water mixture did have a slightly negative effect on the process; there was substantial microbial recovery when bottles were kept in the dark overnight. In the case of the lime juice, it actually inhibited the disinfection process. It is necessary to remove any debris that might exist within the containers before using them, but using a chemical cleaning agent or mechanically scrubbing can decrease the amount of disinfection that occurs during SODIS. Thus, it is suggested that using a chemical pretreatment is not necessary and has the potential to inhibit disinfection, especially without proper training or technical knowledge. <br/><br/> The second series of experiments identified the optimal design for a low-cost roughing filter that could be used to remove particles from water before exposure to sunlight. The roughing filter that was built from the same plastic pop bottles used for solar disinfection, as well as gravel and sand. It was constructed with three centimetres of gravel on the bottom of the pop bottle and then 17 cm of coarse sand was added on top to make the total filter height 20 cm. A 0.6 mm hole was made at approximately 1.5 cm from the bottom of the bottle using a standard sewing needle. Each filter run consisted of 10 L of water at approximately 200 NTU. Experimental results indicated that 95% removal of turbidity could be achieved. These roughing filters can be constructed from readily available and affordable materials in developing countries and produce an effluent water quality of less than 30 NTU when initial turbidities are greater than 200 NTU. <br/><br/> Finally, the third series of experiments focused on testing the newly developed roughing filter in series with SODIS to evaluate the system as a whole. The results confirmed that using the roughing filter, as a pretreatment to SODIS, is a highly effective means of improving the disinfection potential of the process. These roughing filters produce an effluent water quality of less than 30 NTU, which is required for SODIS, making them a viable pretreatment for turbid water intended for SODIS use.

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