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Desenvolvimento e caracterização de um reator eletrolítico para desinfecção de águas contaminadas com escherichia coli. / Development and characterization of an electrolytic reactor for disinfection of water contaminated with escherichia coli.MEDEIROS, Mariana Rodrigues de. 16 August 2018 (has links)
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Previous issue date: 2018-04-10 / Capes / A inativação de bactérias patogênicas é um requisito fundamental no tratamento de
água potável. Os avanços na pesquisa de tratamento de água têm sido direcionados
para a aplicação de tecnologias que usam menos reagentes químicos, reduzindo
assim a formação de subprodutos tóxicos e reduzindo o tempo de operação. Para
tanto, objetivou-se projetar e avaliar a eficiência de um reator eletrolítico de bancada,
composto pelo par de eletrodos: esponja de níquel (ânodo) e fibra de carbono
(cátodo), operando de forma contínua, na desinfecção da bactéria indicadora
Escherichia coli (E. coli). Inicialmente, os ensaios foram realizados com água de
abastecimento público do LABDES/UFCG, contaminada em laboratório com uma
concentração constante, avaliando os efeitos da aplicação das diferenças de
potenciais (ddp) de 3,0 V, 5,0 V, 7,0 V e 9,0 V nos respectivos tempos médios de
residência (tm): 46,8 s, 65,4 s, 82,2 s e 121,8 s, estimados experimentalmente através
do método de injeção de uma solução traçadora (NaCl), nas vazões de 0,5, 1,0, 1,5 e
2,0 L.min-1, respectivamente, nos parâmetros físico-químicos e na desinfecção de E.
coli dessa água. Posteriormente, foi proposto o estudo do desempenho do reator em
relação aos mesmos parâmetros (condutividade elétrica, pH, turbidez e cor),
acrescentando a análise de concentração de cloreto (Cl-). Nessa etapa, foram
consideradas maiores faixas de ddp e um tempo médio de residência constante
(121,8s), e avaliando diferentes tipos de águas (deionizada, solução de NaCl, água
de abastecimento público de Campina Grande) sem e com contaminação de E. coli.
Os resultados obtidos, em termos de percentuais de desinfecção de E. coli na água
do LABDES, mostraram que sob as ddp de 5,0 e 7,0 V, esses percentuais foram de
99,84 e 99,40%, respectivamente para o maior tempo de residência (121,8 s). Nos
experimentos realizados com as outras águas, chegou-se a 100% de desinfecção de
E. coli na solução de NaCl contaminada com 103UFC.mL-1, nas densidades de
corrente de 9,4 e 11,89 mA.cm-2, respectivamente, e na água de abastecimento
público de Campina Grande nessa mesma ordem de concentração de bactéria, a
desinfecção se mostrou 100% eficaz nas densidades de corrente de 9,92, 11,1 e 11,7
mA.cm-2. Os resultados mostram que a proposta do trabalho em remover grande parte
ou 100% de E. coli de águas, principalmente as águas de consumo humano, foi
alcançada. / Inactivation of pathogenic bacteria is a fundamental requirement in the treatment of
drinking water. Advances in water treatment research have been directed toward the
application of technologies that use fewer chemical reagents, thereby reducing the
formation of toxic byproducts and reducing the time of operation. The objective of this
study was to design and evaluate the efficiency of an electrolytic bench reactor
composed of the electrode pair: nickel sponge (anode) and carbon fiber (cathode),
continuously operating in the disinfection of the indicator bacterium Escherichia coli (E.
coli). Initially, the tests were carried out with LABDES / UFCG public contaminated
water in a laboratory with a constant concentration, evaluating the effects of applying
the potential differences (ddp) of 3.0 V, 5.0 V, 7.0 V and 9,0 V in the respective average
residence times (tm): 46.8 s, 65.4 s, 82.2 s and 121.8 s, estimated experimentally by
the method of injection of a tracer solution (NaCl) at the flow rates of 0.5, 1.0, 1.5 and
2.0 L.min-1, respectively, in the physico-chemical parameters and in the disinfection of
E. coli from this water. Subsequently, it was proposed to study the performance of the
reactor in relation to the same parameters (electrical conductivity, pH, turbidity and
color), adding the analysis of chloride concentration (Cl-). In this step, we considered
greater ranges of ddp and a mean constant residence time (121.8s), and evaluating
different types of water (deionized, NaCl solution, public supply water of Campina
Grande) without and with E. contamination. coli. The results obtained, in terms of
percentages of disinfection of E. coli in LABDES water, showed that under the ddp of
5.0 and 7.0 V, these percentages were 99.84 and 99.40%, respectively, for the highest
time of residence (121.8 s). In the experiments performed with the other waters, 100%
disinfection of E. coli was achieved in NaCl solution contaminated with 103 CFU.mL
-1, at current densities of 9.4 and 11.89 mA.cm-2, respectively, and in the public supply
water of Campina Grande in the same order of concentration of bacteria, disinfection
was 100% efficient at current densities of 9.92, 11.1 and 11.7 mA.cm-2. The results show that the proposal of the work to remove much or 100% of E. coli from waters, mainly waters of human consumption, was reached.
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Booster Disinfection In Water Distribution NetworksSert, Caglayan 01 July 2009 (has links) (PDF)
Disinfection of the municipal water systems is mostly achieved by means of chlorine
addition at water treatment plants known as sources. Thus, there should be an adequate
chlorine concentration at the source for an effective disinfection throughout the system
by considering upper and lower limits of disinfectant. However, since the disinfectants
are reactive and decays through the system, chlorine added at the source may not
be enough to maintain desired disinfectant residuals which may lead to water quality
problems in the water distribution system. Moreover, the disinfectants such as chlorine
has also an effect to be carcinogen due to formation of disinfectant by-products. Thus,
the system should balance the amount of disinfectant supplied while minimizing the
health risk. In such a case, it is recommended that one or more booster disinfection
stations can be located throughout the system. Such a method can provide more uniform
distribution of the chlorine concentration while reducing the amount of the disinfectant
used. In this thesis, optimum scheduling, and injection rates of the booster disinfection
stations have been searched. The objective is to minimize the injected mass dosage
rate subjected to the provision of adequate and more uniform residual concentration in
the network. Determination of variable network hydraulics and chlorine concentrations
is held out by EPANET network simulation sofware. A C++ code was developed to
interface with EPANET by means of the EPANET Programmer' / s Toolkit for linear optimization of the disinfectant mass dosage rate applied to the network.
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Desinfec??o solar de ?gua para comunidades de baixa rendaFelix, Lorna Falc?o 11 August 2010 (has links)
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Previous issue date: 2010-08-11 / The use of solar energy for water disinfection, and is accessible to disadvantaged communities because of its low cost, has the advantage of using disposable materials such as bottles of polyethylene terephthalate (PET). We present a study that used two methods of disinfection: the methodology proposed by the project Solar Water Disinfection (SODIS), which consisted of water disinfection by solar radiation and temperature and the methodology which the temperature of the water for disinfection. In both, we seek to eliminate microorganisms that cause serious diseases such as dysentery, typhoid, cholera, etc. Water samples were collected in the community of Bass, where the population has low income and the incidence of waterborne diseases is high. The experiments were divided into two stages. In step 1 we studied the feasibility of disinfection and in step 2 the feasibility of the pilot plant to obtain adequate levels of disinfection temperatures desired. The results showed the efficiency of the disinfection process, reaching an average of 80 to 100% death of microorganisms, but regrowth was observed in some samples. Finally on the good results of stage 1, is designed and built and tested in an experimental pilot plant, which has shown to be feasible to promote water disinfection through the use of solar energy. The water after treatment is in accordance with the limits established by Brazilian legislation for clean water, maintaining a positive performance for the disinfection and acceptable levels of bacterial regrowth / A utiliza??o da energia solar para desinfec??o de ?gua, al?m de ser acess?vel para comunidades menos favorecidas pelo seu baixo custo, tem a vantagem de utilizar materiais descart?veis como garrafas de politereftalato de etileno (PET). Apresenta-se um estudo que utilizou duas metodologias de desinfec??o: a metodologia proposta pelo projeto Solar Water Disinfection (SODIS) que consistiu na desinfec??o da ?gua pela radia??o solar e pela temperatura e a metodologia que utilizou a temperatura da ?gua para a desinfec??o. Em ambas, busca-se eliminar microrganismos causadores de s?rias doen?as como disenterias, febre tif?ide, c?lera, etc. As amostras de ?gua foram coletadas na comunidade do Robalo, local onde a popula??o possui baixa renda e a incid?ncia de doen?as de veicula??o h?drica ? alta. Os experimentos foram divididos em duas etapas: Na etapa 1 estudou-se a viabilidade da desinfec??o e na etapa 2 a viabilidade da planta piloto na obten??o de n?veis de temperaturas adequados ? desinfec??o pretendida. Os resultados obtidos mostraram a efici?ncia do processo de desinfec??o, atingindo uma m?dia de 80 a 100% de morte dos microorganismos, por?m foi observado recrescimento em algumas amostras. Finalmente, diante dos bons resultados da etapa 1, projetou-se, construiu-se e ensaiou-se uma planta piloto experimental, que demonstrou-se vi?vel para promover a desinfec??o de ?gua atrav?s do uso da energia solar. A ?gua, ap?s o tratamento, encontra-se de acordo com os limites estabelecidos pela legisla??o brasileira para ?gua tratada, mantendo um desempenho favor?vel na desinfec??o e ?ndices aceit?veis do recrescimento bacteriano
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