a b s t r a c tThe combination of coagulation/flocculation and ultrafiltration in the process of drinking water treatment was investigated using natural (chitosan) and chemical (aluminum sulfate) coagulants. A 0.1 m singlechannel membrane was applied at pressures of 1 bar and 2 bar, using the principle of crossflow filtration. The final produced water quality was assessed considering the efficiency of removal of color, turbidity, COD, and compounds that absorb UV at 254 nm, among other physico-chemical and microbiological parameters. The coagulation/flocculation with chitosan as coagulant (CFQ) was efficient in removing compounds that add color and turbidity and that absorb UV at 254 nm, with levels that were very similar to those obtained with the coagulation/flocculation process with aluminum sulfate as coagulant (CFS). Performance evaluation of the hybrid systems (CFS-UF and CFQ-UF) showed that the permeate quality was increased when compared with individually operated systems (UF, CFS, and CFQ). The CFQ-UF process caused higher membrane fouling (79% at 2 bar), but yielded a higher stabilized permeate flux, which was approximately twice that achieved with CFS-UF. Based on the results, one can say that chitosan has a potential application as natural coagulant in CF-UF hybrid processes for treating drinking water with relatively high turbidity.
ABSTRACT. This work suggests the study of the coagulation diagram as a tool to verify the efficiency in removing color and turbidity of the water, using the Moringa oleifera Lam and the association of this biopolymer with the aluminium sulphate as coagulating agents. The assays were carried out in Jar Test, by varying the concentrations of coagulants and pH of coagulation. After the assays of coagulation/flocculation/sedimentation, samples were collected for the evaluation of the process efficiency. Best results were obtained at dose of 50 ppm of Moringa oleifera Lam. When associating the coagulants, the addition of the aluminium sulphate provided an increase in the efficiency of coagulation/flocculation, whose parameters of control used were color and turbidity. It was verified that the study of the coagulation diagram is useful, since it enables developing the assays in the optimal range, as a function of the raw water characteristics. The use of the Moringa oleifera Lam can be considered as an alternative technique to the conventional treatment.Keywords: water treatment, biopolymer, chemical coagulant, quality parameters.Diagramas de coagulação utilizando a Moringa oleifera Lam e o sulfato de alumínio, visando a remoção de cor e turbidez da água RESUMO. Este trabalho propõe o estudo dos diagramas de coagulação como ferramenta para verificar a eficiência de remoção de cor e turbidez da água bruta, utilizando como coagulante a Moringa oleifera Lam e a associação deste biopolímero com o sulfato de alumínio. Os ensaios foram realizados em Jar Test, variandose as concentrações dos coagulantes e o pH de coagulação. Após os ensaios de coagulação/ floculação/sedimentação, foram coletadas amostras para a avaliação da eficiência do processo. Os melhores resultados obtidos para os parâmetros avaliados corresponderam a uma dosagem de solução padrão de Moringa oleifera Lam equivalente a 50 ppm. Quando da associação dos coagulantes, a adição do sulfato de alumínio proporcionou um aumento na eficiência da coagulação/floculação, cujos parâmetros de controle utilizados foram cor e turbidez. Verificou-se que o estudo do diagrama de coagulação é útil, pois possibilita o desenvolvimento dos ensaios nas regiões ótimas, em função das características da água bruta. A utilização da Moringa oleifera Lam pode ser considerada como uma técnica alternativa ao tratamento convencional.Palavras-chave: tratamento de água, biopolímero, coagulante químico, parâmetros de qualidade.
RESUMO.Este trabalho tem como objetivo a avaliação dos benefícios da obtenção de água potável a partir de coagulantes naturais, em função da remoção dos parâmetros cor, turbidez e compostos com absorção em UV-254 nm, utilizando como agente coagulante o Tanfloc SS. Com esta finalidade, ensaios de coagulação/floculação/sedimentação foram realizados em aparelho "jar test", com água superficial de características de alta cor/turbidez. O pH de coagulação (3,0 a 9,0) e a concentração do coagulante (10,0 a 60,0 mg L -1 ) foram variados com a finalidade da construção dos diagramas de coagulação e a determinação das regiões de melhor eficiência de remoção de cor e turbidez. As condições de trabalho para o processo de coagulação/floculação/sedimentação foram fixadas de acordo com ensaios prévios. Com os dados obtidos, o diagrama de coagulação foi construído utilizando o programa 3DField 2.7.0.0. Com base nestes diagramas, para o coagulante Tanfloc SS, concluiu-se que as melhores remoções dos parâmetros estudados, em sua maioria, ocorreram para a faixa de pH entre 6,0 e 9,0 em todas as concentrações estudadas. Desta forma, constatou-se que a utilização de coagulantes orgânicos biodegradáveis é, portanto, uma alternativa técnica aos coagulantes convencionais, possuindo benefícios de saúde pública além de preservação ambiental.Palavras-chave: coagulantes naturais, taninos vegetais, Tanfloc, água potável.ABSTRACT. The benefits of using natural coagulants to obtain potable water. This work aims to evaluate the benefits of obtaining potable water from natural coagulants, in function of the removal of the parameters color, turbidity and compounds with absorbing in UV-254 nm, using Tanfloc SS as a coagulant. To that end, coagulation/flocculation/sedimentation tests were performed in jar test with surface water featuring high color/turbidity. The coagulation pH (3.0 to 9.0) and the concentration of coagulant (10.0 to 60.0 mg L -1 ) were varied with the purpose of constructing coagulation diagrams and determine regions of best efficiency for removal of color and turbidity. The working conditions for the process of coagulation/flocculation/sedimentation were set according to preliminary tests. With the data obtained, the coagulation diagram was built using the 3DField 2.7.0.0 software. Based on these diagrams, for the coagulant Tanfloc SS, it is concluded that the best removals of the parameters studied, in their majority, occurred in the range of pH between 6.0 and 9.0 in all the concentrations studied. Thus, it was noted that the use of biodegradable organic coagulant is therefore a technical alternative to conventional coagulants, with public health benefits in addition to environmental preservation.Key words: natural coagulants, vegetable tannin extracts, Tanfloc, potable water. IntroduçãoNa atualidade, os principais recursos hídricos utilizados para abastecimento público são mananciais superficiais cuja qualidade da água, na grande maioria das vezes, apresenta-se degradada.Nestas condições, a utilização de agentes floculantes t...
The natural organic matter (NOM) is a mixture of many organic compounds that can be dispersed in superficial water. The NOM is due to the compounds formed in the biologic degradation process of the vegetable organic matter and its interaction with the clay and the other hydrographic basin soil constituents, besides algae and other microorganism activity. Many researchers have obtained results that indicate that the coagulation/flocculation process is an effective process in the NOM reduction without committing the non-stabilization colloidal particles. So, with the intuit to guarantee a better final water quality in the water treatment plants, different studies were evaluated based on the coagulation diagram for obtaining the best concentration of the chitosan coagulant as function of the pH for the NOM removal for obtaining potable water. The data for the coagulation diagram construction will be obtained by a series of tests in a jar-test apparatus. Different concentrations of the coagulant solution (0.1% w/v of chitosan) will be studied. The pH will be varied (4.0 8.5) with sodium hydroxide solution (NaOH) and hydrochloric acid (HCl) 25 and 50%. The rapid mixture gradient, the coagulation time, the slow mixture gradient and the flocculation time will be maintained constant during this experiment. The process efficiency will be evaluated by the color, turbidity and compounds with absorption in UV-254nm removal. The best results of removal were found for the chitosan in the concentration of 1.0mg/L and pH between 4.0-5.0, approximately.
RESUMOObjetivou-se, neste trabalho, avaliar a persistência e a lixiviação de endossulfam no campo e sua degradação e formação do metabólito sulfato de endossulfam em condições de laboratório. Visando ao experimento da persistência e à lixiviação no campo, amostras de solo até a profundidade de 100 cm foram coletadas aos 0, 41, 74 e 125 dias após aplicação. Em laboratório amostras de solo nas profundidades de 0-30 e 50-70 cm foram incubadas a 30 ± 2 °C e 80% da capacidade de campo e os resíduos de endossulfam e sulfato de endossulfam foram quantificados em função do tempo para ajuste dos modelos de cinética de primeira ordem e do modelo bifásico. Observou-se, no campo, que o endossulfam não lixiviou para menos de 10 cm de profundidade e houve uma rápida dissipação resultando em uma quantidade remanescente no perfil do solo (100 cm) inferior a 1% da dose aplicada aos 41 dias após a aplicação. Em laboratório os valores de TD 50 para o endossulfam variaram de 17 a 26 dias e para o sulfato de endossulfam de 26 a 59 dias. O modelo de degradação bifásico mostrou-se superior ao de cinética de primeira ordem para descrever a degradação do endossulfam em laboratório. Palavras-chave: degradação, meia-vida, lixiviação, dissipaçãoPersistence of endosulfan and its metabolite endosulfan sulfate under field and laboratory conditions ABSTRACT This study aimed to evaluate endosulfan leaching and persistence in the field as well as its degradation and formation of the metabolite endosulfan sulfate under laboratory conditions. For the persistence experiment and leaching in the field, soil samples until 100 cm depth were collected at 0, 41, 74, and 125 days after application. In the laboratory, soil samples of 0-30 cm and 50-70 cm depth were incubated at 30 ± 2 ºC and 80% field capacity and endosulfan residues were quantified as a function of time for adjusting the first order kinetics and biphasic models. In the field, it was observed that endosulfan did not leach beyond 10 cm depth and there was a rapid dissipation resulting in a quantity in the soil profile (100 cm) less than 1% of the applied dose at 41 days after application. In laboratory TD 50 values for endosulfan ranged from 17 to 26 days and endosulfan sulfate 26-59 days. The biphasic decay model was superior to the first-order kinetics to describe the degradation of endosulfan in the laboratory.
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The objective of this study is to evaluate the perception of education professionals, before and after the application of theoretical and practical training based on active methodologies, on safety and prevention against fire and evacuation in disaster situations. The research method adopted is an action research, as it involves diagnosis, planning, action and evaluation to identify the perception of fire protection education professionals. The population consists of 29 education professionals and 75 students, aged between 4 and 5 years, from a private school in the city of Itabira-MG. The structured questionnaire technique is used for teachers and employees, applied before the project to measure the interviewees 'prior knowledge and after the project, to evaluate the effectiveness of the applied training, the teachers' perception of their and children's learning and the need for the topic to be an issue that the school community should constantly address as an important issue in the school calendar schedule. The results indicate that it is necessary to adopt safety training in schools and to keep this training constant. It is concluded that if teachers and school staff undergo regular training they will be able to act consciously, with students, in an emergency. That it is important to use scientific methods so that a broad and effective learning occurs and it is necessary to adopt the theme in the syllabus of schools.
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