Estudo comparativo entre decantadores de fluxo horizontal e de fluxo laminar

A partir da década de 70 tem sido grande o uso de sistemas de decantação acelerada de fluxo laminar, tanto com módulos tubulares como com placas paralelas. Também têm sido vários os casos de adaptações de decantadores tipo convencional para laminar. Estas adaptações têm-se mostrado mais econômicas em estudos alternativos com a construção de novos de cantadores convencionais. O presente trabalho mostra como estão funcionando um grupo de decantadores de fluxo laminar e um grupo de decantadores. tipo convencional; analisa o comportamento de decantadores em relação ao seu grupo e confronta o comportamento dos dois tipos de decantação. Estas análises indicam que tanto um tipo como o outro, apresenta em geral boa eficiência de remoção de turbidez, de cor e de resíduos. Entretanto, mostram que os decantadores tipo laminar, são mais constantes na eficiência de remoção de turbidez, enquanto que os do tipo convencional chegam a apresentar eficiência excelente de remoção de turbidez, mas apresentam também, por vezes, eficiência péssima, não mantendo um padrão de tratamento.The settling basins of high - rate sedimentation with laminar flow have been very used since the last decade. For these basins it has been applied the inclined tubes as much as the parallel plates. It has also been usual adaptations of conventional basins by inserting inclined tubes or parallel plates. These adaptations are cheaper than the building of new conventional basins. This dissertation presents the performance results of a set of settling basins of high-rate sedimentation with laminar flow and of a set of conventional settling basins. It analyses the performance of each basin related to the others of the some set and also compare the results of both sets. These studies show that both types of settling basins are efficient for removing turbidity, color and solid residues. However, the results show that the basins with laminar flow present more constant efficiency in removing the turbidity than the conventional type basins. The last ones are sometimes highly efficient and sometimes present very low efficiency for removing the turbidity

Biodegradation of hepatotoxin (D-Leu1) - microcystin-LR by bacteria in carbon biological filters

A persistência das microcistinas (MCs) em ambientes aquáticos e sua difícil remoção no tratamento convencional de água representam um desafio às companhias de saneamento. Contudo, as MCs são susceptíveis à degradação por bactérias presentes na água, sedimentos e efluentes de esgotos. Neste estudo, avaliou-se a biodegradação de MCs por microrganismos presentes em filtros de carvão com atividade biológica (CAB) e sua identificação filogenética pelo sequenciamento do gene 16S RNA. Foi utilizada uma água de estudo contendo MCs com diferentes composições, acrescida de efluente de filtros CAB. Os resultados demonstraram que as MCs foram biodegradadas por microrganismos presentes no biofilme. Este estudo infere sobre a capacidade de biodegradação de MCs por bactérias presentes em filtros CAB e o possível uso destes microorganismos como alternativa de remoção de MCs no tratamento de água potável.The persistence of MCs in aquatic environments and their difficult removal in the conventional water treatment is a challenge to companies of sanitation. However, the MCs are susceptible to degradation by bacteria present in water, sediment and sewage effluents. In this study, we investigated the biodegradation of MCs by microorganism present in carbon filters with biological activity (BAC) and their phylogenetic identification by sequencing gene 16S RNA. A study of water containing MCs was used, with different compositions, plus a filters BAC effluent. The results showed that of MCs were biodegraded by microorganism present in the biofilm. This study provides the ability to complete biodegradation of MCs by bacteria present in BAC filters and the possible use of these microorganisms as alternative of the removal of MCs in the treatment of drinking wate

not available

A presença de substâncias húmicas na água de abastecimento tem recebido a atenção de diversos pesquisadores nas últimas décadas, pois pode gerar subprodutos ao ser exposta a agentes oxidantes e desinfetantes. A filtração em múltiplas etapas (FiME) se apresenta como uma alternativa para realizar o tratamento de água de comunidades de pequeno porte, entretanto, a eficiência quanto à remoção de cor verdadeira associada ao carbono orgânico dissolvido ou às substâncias húmicas, tem sido questionada ou relatada como baixa. A filtração lenta com pré-ozonização vem sendo utilizada, pois o ozônio atua nas moléculas da matéria orgânica, aumentando sua biodegradabilidade e seus subprodutos desaparecem logo após a aplicação. A aplicação conjunta do ozônio e peróxido de hidrogênio, tem o objetivo de produzir espécies com radicais livres, de vida curta, que sejam altamente reativos e possam oxidar a maior parte das substâncias presentes na água natural. A presente pesquisa avaliou a remoção de substâncias húmicas na filtração lenta, utilizando para essa avaliação parâmetros indiretos como cor verdadeira, absorvância 254 nm e carbono orgânico dissolvido. Foram realizados cinco ensaios utilizando quatro filtros lentos, sendo dois com camada de carvão ativado granular (CAG), em que foram ensaiadas várias alternativas de pré-oxidação com ozônio e peróxido de hidrogênio. Obteve-se, como principal conclusão, que os filtros lentos com CAG, precedidos de oxidação com ozônio e depois peróxido de hidrogênio, em dosagens adequadas, apresentaram remoção média de cor verdadeira de 64% da cor inicial. Concluiu-se, também, que o peróxido de hidrogênio afeta o desenvolvimento da camada biológica, interferindo no desenvolvimento da perda de carga, na remoção de turbidez e na remoção de substâncias húmicas.The presence of humic substances in the water of supply has been received attention of several researchers in the last decades, because it can generate by-products when being exposed to oxidants and disinfectant. The multistage filtration (FiME) is an alternative considered to achieve water treatment for small size rural communities, however, the efficiency with relationship to the removal of true color associated to the dissolved organic carbon or to the humic substances, it has been questioned or reported as low. The slow filtration with pre-ozonation is being used, since the ozone acted in the molecules of the organic matter of high molecular weight, increasing its biodegradability and by-products disappear soon after the application. The combined application of the ozone and hydrogen peroxide have the objective of producing species with free radicals, of short-lived, that are highly reagents and can oxidize most of the present substances in the natural water. The present research it evaluated the removal of humic substances in the slow sand filtration, using for that evaluation indirect parameters as true color, absorbance 254 nm and dissolved organic carbon. Five experiments were realized using four slow filters, being two with layer of activated carbon to granulate (CAG), in that several pre-oxidation alternatives were rehearsed with ozone and peróxido of hydrogen. It was obtained, as main conclusion that the slow filters with CAG preceded ofoxidation with ozone and hydrogen peroxide, in appropriate dosagens, presented medium removal of true color of 64% of the initial color. It was also concludes that the hydrogen peroxide interferes the development of the biological layer, interfering in the development of the loss of head, in the turbidity removal and in the removal of humic substances

Remoção de substâncias húmicas por meio da oxidação com ozônio e peróxido de hidrogênio e FiME

A filtração em múltiplas etapas (FiME) se apresenta como uma alternativa para realizar o tratamento de água de comunidades de pequeno porte, entretanto, a eficiência quanto à remoção de cor verdadeira associada ao carbono orgânico dissolvido (COD) ou às substâncias húmicas, tem sido questionada ou relatada como baixa. A presente pesquisa avaliou a remoção de substâncias húmicas na FiME com pré-oxidação, com ozônio e peróxido de hidrogênio, utilizando para essa avaliação parâmetros indiretos como cor verdadeira, absorvância UV (254 nm) e COD. Foram realizados cinco ensaios, utilizando quatro filtros lentos, sendo dois com camada de carvão ativado granular (CAG). Foram ensaiadas várias alternativas de pré-oxidação com ozônio e peróxido de hidrogênio. Foram obtidos bons resultados, tendo como principal conclusão que os filtros lentos com CAG, precedidos de oxidação com ozônio e depois peróxido de hidrogênio, apresentaram remoção média de cor verdadeira de 64%, mas que o peróxido de hidrogênio afeta o desenvolvimento da camada biológica, interferindo no desenvolvimento da perda de carga, na remoção de turbidez, na remoção de coliformes e na remoção de substâncias húmicas.The multistage filtration (FiME) is an alternative to accomplish water treatment for small communities, however, as for removal of true color associated to dissolved organic carbon (DOC) or humic substances, it have been questioned or reported as low efficiency. The present research evaluated the removal of humic substances in the FiME using ozone and hydrogen peroxide as a pre-oxidation, using for this indirect parameters how true color, UV absorbance (254nm) and DOC. Five experiments were conducted using four slow filters, from this two were composed the intermediate layer of granulate activated carbon (GAC). The assays were conducted with pre-oxidation alternatives using ozone and hydrogen peroxide in several applications forms. It was obtained good result, as main conclusion were the slow filters with GAC, preceded of oxidation with ozone and hydrogen peroxide in appropriate dosage, presented medium removal of true color of 64%, but that the hydrogen peroxide interfering in the development of the biological layer, in the increase of the head loss, in the turbidity removal, in the coliforms removal and in the humic substances removal

Electrolytic process applied with addition of salts for color removal in drinking water treatment

In this paper the electrolytic process application as a water purification treatment stage from the Ipê neighborhood lake (Ilha Solteira –São Paulo, Brazil–) was evaluated. The treatment efficiency for apparent and true color removal, in samples by addition of humic substances, to reach different colors levels was determined. It was monitored the 1 g/L NaCl and TiO2 addition individual effect. The removal efficiency for each trial in samples taken from the electrolytic reactor each 10 minutes during one hour, were calculated.For the water sample with initial apparent color of 25 Hu, it was reduced up to 15 Hu –maximum permitted value according the Brazilian drinking water guidelines– after 30 reaction minutes. For the apparent water color with 66 Hu, with sodium chloride addition, a reduction up to 13 Hu was measured after one hour reaction. In the trials with humic substances addition, the apparent color removal for water with 708 and 247 Hu, were 87.3 % and 84.2 %, respectively, after 60 minutes of reaction.The results showed the electrolytic process performance with use of salts as a drinking water treatment stage, both for the apparent color reduction below the maximum permitted values defined by the legislation, as for its removal up to certain levels, treatment stage that should be complemented by additional stages. Se evaluó el proceso electrolítico como etapa de tratamiento para la potabilización de agua del lago del barrio Ipê (Ilha Solteira –São Paulo, Brasil–). Se determinó la eficiencia del tratamiento para la remoción de color aparente y verdadero sobre muestras a las que se adicionaron sustancias húmicas para alcanzar diversos niveles de color. Se evaluó el efecto individual de la adición de 1 g/L de NaCl y de TiO2. Para cada ensayo se calculó la eficiencia de remoción a partir de muestras tomadas del reactor electrolítico en intervalos de 10 minutos durante una hora. Para agua con color aparente inicial de 25 uH se redujo hasta 15uH –nivel máximo permitido por la norma brasilera de agua potable– en 30 minutos de reacción, para agua con 66 uH de color aparente, con adición de sal, se redujo hasta 13 uH en el término de una hora. En los ensayos con adición de sustancias húmicas, la remoción de color aparente para agua con 708 y 247 uH fue, respectivamente, de 87.3 y 84.2 % después de 60 minutos de reacción. Los resultados mostraron el desempeño del tratamiento electrolítico con uso de sales como etapa de potabilización del agua, tanto para alcanzar los niveles de color aparente establecidos por la legislación, como para su remoción hasta ciertos niveles, etapa de tratamiento que ha de ser complementada por otras posteriores

Utilización de columnas verticales de filtración de manta y arena como pre-tratamiento de un sistema de filtración lenta

Slow sand filtration is an efficient water treatment technique used for treating surface water with relatively low levels of contamination. Despite the slow sand filtration at pathogen, algae and cyanobacteria removal efficiency, it has some restrictions in relation to the required area for slow filters, and the cleaning activities for the filters and the stone pre-filters when used in the treatment. This research evaluated during 120 days the use of non woven & sand pre-filtration columns as part of a slow filtration process for the apparent color, turbidity, algae, cyanobacteria, phytoflagellates and diatomaceous. The columns shown an efficient removal of the monitored parameters and demonstrated as a vantage their faster and easier cleaning process and less awkward than the required to the stone pre-filters. The turbidity removal efficiency increased progressively during the experiment, especially after the first 35 days of the start; the apparent color removal by the pre-filtration columns was of 85%, and working together with the polishing of activated carbon columns was up to 95; the diatomaceous, phytoflagellates, algae and cyanobacteria removal by the columns achieve a weekly average of 95%, its recommended to use filtration rates lower to 1,5m(3)/m(2)/d.La Filtración Lenta es una eficiente técnica de tratamiento de agua superficial con relativamente bajos niveles de contaminación. Pese a su eficiencia en la remoción de patógenos, algas y cianobacterias presenta restricciones en cuanto al área necesaria de los filtros y su limpieza así como la de los pre-filtros de piedra usados en el tratamiento. En esta investigación se evaluó durante 120 días el uso de Columnas Verticales de Pre-Filtración de manta y arena como parte de un proceso de filtración lenta para la remoción de color aparente, turbiedad, algas, cianobacterias, fitoflagelados y diatomáceas. Las columnas evidenciaron una eficiente remoción de los parámetros monitoreados y demostraron como ventaja su procedimiento de limpieza más rápido y menos dispendioso que el requerido por los prefiltros de piedra. La eficiencia de remoción de la turbiedad se incrementó progresivamente en el experimento, especialmente después de 35 días de su inicio; la remoción de color aparente por las columnas de prefiltración fue del 85%, y junto a columnas de pulimento con carbón activado granular removieron hasta el 95%; la remoción de diatomáceas, fitoflagelados, algas y cianobacterias por las columnas alcanzó un promedio semanal de 95%, se recomienda utilizar tasas de filtración inferiores a 1,5m3 /m2 /d

Effects Of Microcurrent Therapy On Excisional Elastic Cartilage Defects In Young Rats

The effects of microcurrent application on the elastic cartilage defects in the outer ear of young animals were analyzed. Sixty male Wistar rats were divided into a control (CG) and a treated group (TG). An excisional lesion was created in the right outer ear of each animal. Daily treatment was started after 24 hand consisted of the application of a low-intensity (20 mu A) continuous electrical current to the site of injury for 5 min. The animals were euthanized after 7, 14 and 28 days of injury and the samples were submitted to analyses. In CG, areas of newly formed cartilage and intense basophilia were seen at 28 days, while in TG the same observations were made already at 14 days. The percentage of birefringent collagen fibers was higher in CG at 28 days. The number of connective tissue cells and granulocytes was significantly higher in TG. Ultrastructural analysis revealed the presence of chondrocytes in TG at 14 days, while these cells were observed in CG only at 28 days. Cuprolinic blue staining and the amount of glycosaminoglycans were significantly higher in TG at 14 days and 28 days. The amount of hydroxyproline was significantly higher in TG at all time points studied. The active isoform of MMP-2 was higher activity in TG at 14 days. Immunoblotting for type II collagen and decorin was positive in both groups and at all time points. The treatment stimulated the proliferation and differentiation of connective tissue cells, the deposition of glycosaminoglycans and collagen, and the structural reorganization of these elements during elastic cartilage repair. (C) 2016 Elsevier Ltd. All rights reserved.48322423