998 resultados para Settleable solids reduction


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An exploratory investigation was conducted on the effects of application of ozone on the removal of organic and inorganic contaminants and the reduction of settleable solids in urban lake sediments. Homogenized sediment samples were treated in a batch reactor with an external recirculation loop and ozone feed from a Venturi injector. The ozone generating system was fed with ambient air with small footprint and operational simplicity. Ozone mass application (g/h) and contact time (min) were varied over wide ranges during testing. The effects of the ozone mass applied per unit time and the contact time on contaminant removal efficiencies were analyzed and a trade-off between the costs of ozonation and of solids treatment and disposal was proposed. The minimum ozone mass application required for total contaminant removal apparently depended on the type of organic contaminant present. An apparent influence of inorganic contaminant speciation on the removal efficiency was found and discussed.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Avaliar o desenvolvimento do processo de compostagem utilizando como substrato à fração sólida da água residuária de suinocultura foi o objetivo deste trabalho. Para a obtenção da fração sólida, a água residuária de suinocultura foi submetida ao peneiramento, utilizando-se de peneira com malha de 1 milímetro. Após separação, a fração sólida foi utilizada para a confecção de três leiras de compostagem, em pátio com piso de concreto e cobertura plástica. Durante a compostagem da fração sólida da água residuária de suinocultura, foram avaliados: temperatura, reduções de sólidos totais (ST), sólidos voláteis (SV), demanda química de oxigênio (DQO), carbono orgânico, matéria orgânica compostável (MOC), matéria orgânica resistente à compostagem (MORC), números mais prováveis (NMPs) de coliformes totais e coliformes termotolerantes, além do volume e dos teores de nutrientes no composto. A compostagem mostrou-se eficiente no tratamento da fração sólida da água residuária de suinocultura devido à elevada minimização do poder poluente dos dejetos, observando-se reduções de 71,24% nos teores de ST, 64,55% no volume, 56,89% no teor de DQO e 56,89% na MOC. Foram verificadas reduções de 100% nos NMPs de coliformes totais e termotolerantes, o que possibilita seu uso como adubo orgânico.

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A viability study of an electrolytic process for the transformation of organic matter and free sulphide contained in wastewater from a fowl slaughterhouse in order to minimise odours was carried out Cast iron and aluminium electrodes were tried at 7.09 mA/cm2, under strong agitation, at 297 K. Conductivity, pH, chemical oxygen demand (COD), amount of settleable solids, and sulphide content were monitored with electrolysis duration. The cast iron electrodes were found to be viable for the elimination of soluble sulphides in the wastewater, leading to the elimination of its strong odour after short times of electrolysis. A significant decrease in COD was also attained.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Zootecnia - FCAV

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This study used a multi-analytical approach based on traditional microbiological methods for cultivation and isolation of heterotrophic bacteria in the laboratory associated with the molecular identification of the isolates and physicochemical analysis of environmental samples. The model chosen for data integration was supported by knowledge from computational neuroscience, and composed by three modules: (i) microbiological parameters, contemplating taxonomic data obtained from the partial sequencing of the 16S rRNA gene from 80 colonies of heterotrophic bacteria isolated by plating method in PCA media. For bacterial colonies isolation were used water samples from Atibaia and Jaguarí rivers collected at the site of water captation for use in effluent treatment, upstream from the entrance of treated effluent from the Paulínia refinery (REPLAN/Petrobras) located in the Paulínia-SP municipality, from the output of the biological treatment plant with stabilization pond and from the raw refinery wastewater; (ii) chemical parameters, ending measures of dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD), chloride, acidity CaCO3, alkalinity, ammonia, nitrite, nitrate, dissolved ions, sulfides, oils and greases; and (iii) physical parameters, comprising the pH determination, conductivity, temperature, transparency, settleable solids, suspended and soluble solids, volatile material, remaining fixing material (RFM), apparent color and turbidity. The results revealed interesting theoretical relationships involving two families of bacteria (Carnobacteriaceae and Aeromonadaceae). Carnobacteriaceae revealed positive theoretical relationships with COD, BOD, nitrate, chloride, temperature, conductivity and apparent color and negative theoretical relationships with the OD. Positive theoretical relationships were shown between Aeromonadaceae and OD and nitrate, while this bacterial family showed negative theoretical...

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This study used a multi-analytical approach based on traditional microbiological methods for cultivation and isolation of heterotrophic bacteria in the laboratory associated with the molecular identification of the isolates and physicochemical analysis of environmental samples. The model chosen for data integration was supported by knowledge from computational neuroscience, and composed by three modules: (i) microbiological parameters, contemplating taxonomic data obtained from the partial sequencing of the 16S rRNA gene from 80 colonies of heterotrophic bacteria isolated by plating method in PCA media. For bacterial colonies isolation were used water samples from Atibaia and Jaguarí rivers collected at the site of water captation for use in effluent treatment, upstream from the entrance of treated effluent from the Paulínia refinery (REPLAN/Petrobras) located in the Paulínia-SP municipality, from the output of the biological treatment plant with stabilization pond and from the raw refinery wastewater; (ii) chemical parameters, ending measures of dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD), chloride, acidity CaCO3, alkalinity, ammonia, nitrite, nitrate, dissolved ions, sulfides, oils and greases; and (iii) physical parameters, comprising the pH determination, conductivity, temperature, transparency, settleable solids, suspended and soluble solids, volatile material, remaining fixing material (RFM), apparent color and turbidity. The results revealed interesting theoretical relationships involving two families of bacteria (Carnobacteriaceae and Aeromonadaceae). Carnobacteriaceae revealed positive theoretical relationships with COD, BOD, nitrate, chloride, temperature, conductivity and apparent color and negative theoretical relationships with the OD. Positive theoretical relationships were shown between Aeromonadaceae and OD and nitrate, while this bacterial family showed negative theoretical...

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El río Mendoza conforma el oasis norte que es el más importante de la provincia. El crecimiento urbano ha avanzado sobre áreas originalmente agrícolas, rodeando la red de canales y desagües, que también recibe los desagües pluviales urbanos, producto de tormentas convectivas. La actividad antropogénica utiliza el recurso para bebida, saneamiento, riego, recreación, etc., y vuelca sus excedentes a la red, contaminándola. Para conocer la calidad del agua de esta cuenca se seleccionaron, estratégicamente, 15 sitios de muestreo: 3 a lo largo del río y a partir del dique derivador Cipolletti (R_I a R_III), 5 en la red de canales (C_I a C_V) y 7 ubicados en los colectores de drenaje (D_I a D_VII). Se realizaron los siguientes análisis físico-químicos y microbiológicos; en el río y en la red de canales: conductividad eléctrica, temperatura, pH, aniones y cationes (cálculo de RAS), oxígeno disuelto (OD), sólidos sedimentables, demanda química de oxígeno (DQO), bacterias aerobias mesófilas (BAM), coliformes totales y fecales y metales pesados. En la red de drenaje sólo se realizaron los cuatro primeros. Los resultados de los análisis, se incorporaron a una base de datos y se sometieron a un análisis estadístico descriptivo e inferencial. Este último consistió en la aplicación de diversas pruebas en busca de posibles diferencias entre los sitios de muestreo, para cada variable respuesta, a un α = 0.05. Se realizó el análisis de la varianza de efectos fijos y de efectos aleatorios y se probaron los supuestos de homocedasticidad y de normalidad de los errores. En el caso de violación de los supuestos, se utilizó la prueba de Kruskal- Wallis. Se compararon los siguientes sitios de muestreo entre sí: ríos, R_I-canales y drenajes. Se concluyó que hay un aumento significativo de la salinidad y la sodicidad en R_II, que los cambios de calidad ocurridos entre R_II y R_III podrían deberse al aporte de otras aguas. Con respecto a la comparación de los parámetros entre la cabeza del sistema (R_I) y la red de canales se puede decir que los aportes realizados por los escurrimientos urbanos ubicados hacia el oeste del canal Cacique Guaymallén, sumados a los vuelcos de Campo Espejo (detectados en C_II), incrementan significativamente la salinidad (+55 %) y sodicidad del agua (+95 %) respecto del punto R_I, aunque el valor de sodicidad sigue siendo bajo. También se han encontrado incrementos de salinidad (+80 %), de DQO (+1159 %) y BAM (+2873 %) con lógica disminución de OD (-58 %) en el punto C_V (canal Auxiliar Tulumaya) respecto del punto R_I, ocasionados por aportes urbanos (Gran Mendoza) sumados a la carga contaminante del canal Pescara. Los metales pesados no presentan grandes diferencias entre sitios de muestreo.

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A concentração demográfica e de sistemas coletivos de esgotamento sanitário dentro do perímetro urbano da maioria dos municípios brasileiros, dificulta a viabilização do fornecimento de serviços de tratamento de esgotos domésticos à habitações e núcleos habitacionais isolados situados em áreas periurbanas e rurais, intensificando os danos provocados pela poluição de origem antrópica ao meio ambiente e à preservação da saúde pública. Para contribuir no equacionamento deste problema, o presente estudo teve por finalidade avaliar uma wetland construída híbrida em escala real, composta por uma unidade com fluxo contínuo subsuperficial vertical seguida por uma unidade de fluxo contínuo subsuperficial horizontal, cultivadas com capim Vetiver, para o tratamento de efluente proveniente de tanque séptico. A presente configuração experimental busca uma solução de baixo custo e simplificada para o tratamento descentralizado de esgotos domésticos. A estação experimental de tratamento de esgotos, parte integrante e um dos produtos da Rede Nacional de Tratamento de Esgotos Descentralizados RENTED, foi construída no Centro Tecnológico de Hidráulica CTH / Escola Politécnica EPUSP, campus Butantã da USP, em São Paulo. O esgoto bruto foi proveniente do Conjunto Residencial da USP e do restaurante central da Cidade Universitária. As vazões média e máxima de esgoto bruto, respectivamente, de 640L.d-1 e 1600L.d-1, foram aplicadas à entrada do TS de 5.000L e deste escoaram por gravidade à entrada da wetland construída híbrida, com TDH total de 2,8d e 1,1d, respectivamente, sob aplicação das vazões média e máxima de projeto. O monitoramento do experimento em campo, incluindo o período inicial de partida, durou 6 meses consecutivos. Foram avaliados os parâmetros físico-químicos e microbiológicos do esgoto bruto e do efluente do tanque séptico e das câmaras da wetland construída híbrida durante 97 dias consecutivos. Os resultados indicaram que tanto as mudas jovens quanto as adultas de capim Vetiver adaptaram-se bem às condições ambientais. As eficiências médias de remoção no efluente tratado final quanto à matéria orgânica carbonácea foram de 96 por cento para DBO5,20 e 90 por cento para DQO, 40 por cento para N-total, 23 por cento para N-amoniacal total, 60 por cento para P-total, 52 por cento para P-PO4, 74 por cento para SST, 96 por cento para SSV, 75 por cento para sólidos sedimentáveis, 44 por cento para SDV, 88 por cento para sulfeto total, e 97 por cento para óleos e graxas totais, variando entre 73 por cento a 100 por cento . Cerca de 80 por cento da fração orgânica da matéria nitrogenada presente no esgoto bruto foi removida. A remoção de coliformes termotolerantes foi, em média, de 2 e 3 unidades log, e de Escherichia Coli, média de 1 e 3 unidades log, respectivamente, sob aplicação das vazões máxima e média, Giardia sp, média de 99,995 por cento , Cryptosporidium sp, média de 98,7 por cento , Enterovírus, média de 99,6 por cento , e Ascaris sp, média de 0,10 ovo/L. A remoção de sulfetos propiciou a geração de efluente tratado sem odores desagradáveis. A diminuição da vazão aplicada e a elevação do TDH influenciaram positivamente no desempenho do sistema com relação às remoções dos parâmetros físico-químicos e microbiológicos. Com base no presente estudo, ficou evidente o benefício da associação de wetlands construídas com fluxo vertical e horizontal no tratamento de efluente de tanque séptico. O capim Vetiver apresentou bom potencial de utilização em wetlands 8 construídas para tratamento de esgotos domésticos. O sistema experimental de tratamento apresentou flexibilidade operacional, mantendo bom desempenho inclusive nos períodos de sobrecarga. A qualidade do efluente tratado final obtido no presente estudo atende às exigências de lançamento e aos padrões de emissão de efluentes líquidos em corpos dágua e em sistemas públicos de esgotamento sanitário definidos na legislação ambiental federal e do Estado de São Paulo. A tecnologia de wetlands construídas híbridas associada ao tratamento de efluentes de tanque séptico apresentou bom potencial para o tratamento descentralizado de esgotos domésticos, inclusive em regiões com pouca disponibilidade de área livre.

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The water supply and treatment is considered as a great benefit considering that, if done efficiently, provides public health. However, considering the WTP (Water Treatment Plant) is an industry, with its inputs and waste generation, they must be constantly evaluated and monitored to verify the best and most appropriate way to process and dispose their waste, minimizing therefore the potential impacts to the environment. By volume, the most significant waste is the rapid filter backwash water. It is very common the disposal of this waste without treatment in water sources, which are used, for the most part, as a water supply source of a downstream population. This study evaluated quantitative and qualitative parameters in filter backwash water in three WTP - Itaitinga, Maranguape and Pacatuba, located in Ceará State, northeast of Brazil. It was found that the Maranguape WTP, in terms of treatment capacity, is the larger. The Itaitinga WTP is the one that consumes more water during filters washing. The Pacatuba WTP exhibited higher concentration of total suspended and settleable solids, COD and aluminum in the filters backwash water. It is noteworthy that the settleable solids and total suspended solids in all three WTP are above the effluent discharge standard recommended by Resolution 154/2002 of SEMACE (State Superintendent of Environment of Ceará). It was concluded that the filter backwash water from the study WTP exceeded the allowed values for legislation to be disposed directly into surface water bodies. It is suggested as an alternative to treat and recycle the filter backwashing water the construction of sludge settling ponds.

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A paradigm for internally driven matter is the active nematic liquid crystal, whereby the equations of a conventional nematic are supplemented by a minimal active stress that violates time-reversal symmetry. In practice, active fluids may have not only liquid-crystalline but also viscoelastic polymer degrees of freedom. Here we explore the resulting interplay by coupling an active nematic to a minimal model of polymer rheology. We find that adding a polymer can greatly increase the complexity of spontaneous flow, but can also have calming effects, thereby increasing the net throughput of spontaneous flow along a pipe (a ``drag-reduction'' effect). Remarkably, active turbulence can also arise after switching on activity in a sufficiently soft elastomeric solid.

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Background: Recommendations for the introduction of solids and fluids to an infant’s diet have changed over the past decade. Since these changes, there has been minimal research to determine patterns in the introduction of foods and fluids to infants. Methods: This retrospective cohort study surveyed mothers who birthed in Queensland, Australia, from February 1 to May 31, 2010, around 4 months postpartum. Frequencies of foods and fluids given to infants at 4, 8, 13, and 17 weeks were described. Logistic regression determined associations between infant feeding practices, the introduction of other foods and fluids at 17 weeks, and sociodemographic characteristics. Results: Response rate was 35.8%. At 17 weeks, 68% of infants were breastfed and 33% exclusively breastfed. Solids and water had been introduced in 8.6% and 35.0% of infants, respectively. The introduction of solids by 17 weeks was associated with younger maternal age and the infant being given water and infant formula at 4 weeks. The infant being given water at 17 weeks was associated with younger maternal age, the infant being given infant formula at 4 weeks, level of education, relative socioeconomic disadvantage, parity, and birth facility. Conclusion: Over the past decade, there has been a significant reduction in the proportion of infants in Australia who have been given solids by 17 weeks. Sociodemographic characteristics and formula feeding practices at 4 weeks were associated with the introduction of solids and water by 17 weeks. Further research should examine these barriers to improve compliance with current infant feeding recommendations.