204 resultados para Tratamento de águas residuais


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Water treatment uses chlorine for disinfection causing formation of trihalomethanes. In this work, an electrolytic water pre-treatment was studied and applied to the water from a fountainhead. The action against microorganisms was evaluated using cast-iron and aluminum electrodes. Assays were made in laboratory using the electrolytic treatment. After 5 min of electrolysis the heterotrophic bacteria count was below 500 cfu/mL and complete elimination of total and fecal coliforms was observed. Using electrolytic treatment as a pretreatment of conventional tap water treatment is proposed.

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Avaliou-se o efeito das águas residuárias de suinocultura com concentrações de sólidos suspensos totais em torno de 6.000 mg L-1 (DQOtotal variando de 7.557 a 11.640 mg L-1) no desempenho de processo anaeróbio em dois estágios compostos por reator compartimentado (ABR) e reator de fluxo ascendente com manta de lodo (UASB), instalados em série, em escala-piloto (volumes de 530 e 120 L, respectivamente), submetidos a tempos de detenção hidráulica (TDH) de 56 a 18 h no primeiro reator e de 13 a 4 h no segundo reator. As eficiências médias de remoção de DQOtotal variaram de 71,1 a 87,5% no reator ABR e de 41,5 a 50,1% no reator UASB, resultando em valores médios de 86,8 a 94,9% para o sistema de tratamento anaeróbio em dois estágios com carga orgânica volumétrica (COV), na faixa de 5,05 a 10,12 kg DQOtotal (m³ d)-1, no reator ABR, e de 2,83 a 9,63 kg DQOtotal (m³ d)-1, no reator UASB. As eficiências de remoção de SST e SSV foram da ordem de 95,6%. O teor de metano no biogás manteve-se acima de 70% para os dois reatores. A produção volumétrica de metano máxima de 0,755 m³ CH4 (m³ d)-1 ocorreu no reator 1, com COV de 10,12 kg DQOtotal (m³ d)-1 e TDH de 18 h. Os valores médios de pH variaram na faixa de 7,2 a 8,0 para os efluentes dos reatores 1 e 2. Os ácidos voláteis totais mantiveram-se estáveis com concentrações abaixo de 200 mg L-1. Com variações abruptas e acentuadas de concentrações de SST e DQOtotal do afluente, os reatores mantiveram as eficiências de remoção de DQO e sólidos suspensos, em torno de 70%, e a qualidade do biogás, com 80% de CH4.

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Avaliou-se o desempenho de um sistema combinado anaeróbio-aeróbio para o tratamento de águas residuárias de suinocultura, com concentrações médias de sólidos suspensos totais (SST) de 18.624 e 11.395 mg L-1. Foram utilizados quatro reatores anaeróbios horizontais com volume total de 49,5 L cada, um com manta de lodo (RAHML) e três de leito fixo (RAHLF), instalados em série e seguidos de um reator aeróbio operado em batelada sequencial (RBS) com volume total de 339 L e com alimentação contínua. Nos RAHLF, foram utilizados como meios suporte de anéis de bambu, anéis plásticos de eletroduto corrugado e anéis de bucha (Luffa cillyndrica), respectivamente. Os tempos de detenção hidráulica (TDH) e as cargas orgânicas volumétricas (COV) aplicadas no RAHML foram de 12 e 10 h e 53 e 61 g DQO (L d)-1, respectivamente. O RBS foi operado com ciclo de 24 h e COV de 0,34 e 0,50 g DQO (L d)-1. As eficiências médias de remoção de DQOtotal e SST para o conjunto de reatores anaeróbios horizontais, em série, foram de 96 e 99%, e de 96 e 95%, respectivamente. As maiores produções volumétricas de metano ocorreram nos RAHLF, com valores médios de até 0,744 m³ CH4 (m³ reator d)-1. A inclusão do RBS permitiu melhorar a qualidade do efluente e a estabilidade do sistema de tratamento, atingindo eficiências de remoção de DQOtotal e SST de 99 e 99%, e de 98 e 99%, respectivamente. No RBS, ocorreu nitrificação e desnitrificação, com remoções de N-amoniacal de até 65%.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Objective. To assess the potential for contamination of wastewaters from pig farming. Methods. Wastewaters from pig farming were stored in a tank. After 0, 30, 60, 90, and 120 days of hydraulic retention, they were added to lysimeters filled with argillaceous, sandy, or medium soil. Finally, these lysimeters were submitted to simulations of either a rainy season or a dry season. The number of colony-forming units (CFUs) of total coliforms, fecal coliforms, and fecal streptococci was measured in the effluents of the storage tank (for the various periods of hydraulic retention), in the percolate from the lysimeters, and in the three types of soil. The microbiological analyses were carried out using the membrane filter technique. The pH analyses were done potentiometrically. Results. For the three microorganisms, the largest decrease in bacterial counts in the storage tanks occurred with 90 or 120 days of retention. There was a marked decrease in the bacterial count in the percolates of the three soils. For the three soil types the greatest reduction in bacterial counts was found in medium soil, due to its acidity (pH < 7.0). Hydraulic retention was not sufficient to ensure the sanitary adequacy of the wastewaters and their use for irrigation, given that fecal coliform values were above 1 000 CFU per 100 mL. Therefore, adding the residues to the soil was considered a second stage of treatment. Conclusions. The retention of wastewaters followed by adding them to soil was effective in minimizing the contaminating effect of pig farming residues. The storage time for wastewaters from pig farming could be decreased from 120 to 90 days.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Engenharia Civil - FEIS

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This study was developed to evaluate the performance of different coagulant and pH dosages by applying the use of Dissolved Air Flotation (FAD) to enable its use in effluent treatment of the extraction process of palm oil. The study was developed in the laboratory, where studies about emulsions stability were made for the production of a synthetic effluent which best suit the characteristics of raw effluent. The synthetic water that would be used in the tests of FAD was produced, once the stability and characterization which best approached the raw wastewater was obtained. Trials tested three coagulant doses, combined with various pH ranges and five upward velocities (Va), finding an optimal range of this combination. Some operating parameters such as time and gradient of rapid mixing (20 s / 1000 s-1), time and gradient flotation (15 min / 60 s-1), chamber pressure saturation (450 kPa) and recirculation rate (20%) were set. In this way, samples were collected for analysis of the removal of turbidity parameters, suspended solids and oils and greases. This one is obtained by a correlation turbidity x oils and greases, referring to the previous analysis. The degree of removal obtained were 73,97% for turbidity, 51,4% for total suspended solids and 86,2% for oils and greases. Removal rates may be increased in later studies, by ranging the velocity gradient and flocculation parameters and the recirculation ratio, and by using lower flotation speeds to these effluent characteristics.

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Cassava wastewater, generated during cassava processing, is a highly polluting and toxic waste. This study aimed to assess the relationship of cassava treatment efficiency in two aerobic sequencing batch reactors, cylindrical plastics (31cm height x 9cm diameter), with 2.0 liters capacity and 1.5 liters of work volume, a ratio of diameter and height of the liquid 1:2.5, with a running time of 24 hours and stoppage aeration for 16 hours with average feed of 2,500 and 6,000 mg COD. L -1. COD, pH, SVI and F/M were analyzed. The results obtained in the two reactors showed an average reduction of 94.1% and 76.8% organic content, respectively; pH values showed a rising in the output pH values compared to entry ones; SVI values obtained: 54.1 mL/g, 99.3 mL/g, respectively in a F/M ratio values worked out of 0.4 d-1 and 1,1 d-1 , respectively. The results demonstrated that the process has generated considerable saving in energy consumption compared to traditional continuous systems, was efficient and did not affect the efficiency overly of the reactor.