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Advisor(s)
Abstract(s)
O tratamento de águas residuais urbanas é uma temática atual e pertinente como medida de
mitigação da poluição das águas, os processos biológicos são aplicados nas ETAR a nível
secundário para remover matéria orgânica.
O estudo objetiva realizar a modelação numérica de reatores biológicos com lamas ativadas de
média carga, para tratamento de águas residuais urbanas com descarga em águas superficiais.
No desenvolvimento de um modelo para o processo de lamas ativadas distinguem-se quatro etapas:
seleção das características quantitativas e qualitativas do afluente, dependentes da população
atendida e de fatores culturais, económicos e sociais; a configuração do esquema de tratamento,
com decantador primário, tanque de arejamento e decantador secundário; o cumprimento das
legislações em vigor em Portugal e no Brasil para descarga em cursos de águas; e aplicação do
modelo de lamas ativadas, ASM1, sendo aplicado para as simulações o programa GPS-X 6.0.
Deste modo, foram realizadas no total 864 simulações, divididas por 4 cenários, que abrangem
ETAR de pequena a grande dimensão, com população de 10.000 a 200.000 hab, sendo que para
cada cenário foram consideradas 8 condições de A a H. Deste modo foram realizadas alterações
nas temperaturas, caudais e cargas poluidoras (CBO5 e SST) para os anos zero, dez e vinte.
Na configuração do sistema de tratamento foram considerados 3 níveis para a operação de
arejamento, recirculação de lamas e purga das lamas nos decantadores com base no QMÍN, QMÉD e
QPTA. No caso do tanque de arejamento, em que foram estudados 2 sistemas de arejamento: com
difusores e agitadores superficiais, os difusores apresentaram menor requerimento de potência.
A escolha da alternativa ótima para cada cenário foi definida a partir dos resultados que
apresentaram melhor qualidade no efluente final e menores custos no arejamento, recirculação e
tratamento de lamas. Em Portugal, onde ocorrem maiores capitações e menores concentrações nos
poluentes que no Paraná, a condição B (decantadores circulares) é superior às demais para os três
primeiros cenários, exceto no cenário 4 em que a condição D, com unidades retangulares,
demonstrou ser a melhor escolha. No Paraná, o formato retangular com a condição F demonstrou
ser a melhor opção para os cenários 1, 2 e 3, e no cenário 4 a geometria circular foi a mais eficiente.
The treatment of urban wastewater is a current and relevant theme as a measure to mitigate water pollution, biological processes are applied in WWTP at secondary level to remove organic matter. The study aims to perform the numerical modeling of biological reactors with activated sludge of medium load, for treatment of urban wastewater with discharge into surface waters. In the development of a model for the activated sludge process, four stages are distinguished: selection of the quantitative and qualitative characteristics of the affluent, dependent on the population served and the cultural, economic and social factors; the configuration of the treatment scheme, with primary decanter, aeration tank and secondary decanter; compliance with the legislation in force in Portugal and Brazil for discharge into water courses; and application of the activated sludge model, ASM1, using the GPS-X 6.0 program for the simulations. Thus, a total of 864 simulations were performed, divided into 4 scenarios, covering small to large WWTP, with a population of 10,000 to 200,000 inhabitants, with 8 conditions from A to H. Thus, changes were made in temperatures, flows and polluting loads (BOD5 and SST) for years zero, ten and twenty. In the configuration of the treatment system, 3 levels were considered for the aeration operation, sludge recirculation and sludge purge in the decanters based on QMÍN, QMÉD and QPTA. In the case of the aeration tank, in which 2 aeration systems were studied: with diffusers and surface agitators, the diffusers had a lower power requirement. The choice of the optimal alternative for each scenario was defined based on the results that presented better quality in the final effluent and lower costs in aeration, recirculation and sludge treatment. In Portugal, where there are higher capitation and lower concentrations of pollutants than in Paraná, condition B (circular decanters) is higher than to the others for the first three scenarios, except in scenario 4 where condition D, with rectangular units, proved to be the best choice. In Paraná, the rectangular format with condition F proved to be the best option for scenarios 1, 2 and 3, and in scenario 4 the circular geometry was the most efficient.
The treatment of urban wastewater is a current and relevant theme as a measure to mitigate water pollution, biological processes are applied in WWTP at secondary level to remove organic matter. The study aims to perform the numerical modeling of biological reactors with activated sludge of medium load, for treatment of urban wastewater with discharge into surface waters. In the development of a model for the activated sludge process, four stages are distinguished: selection of the quantitative and qualitative characteristics of the affluent, dependent on the population served and the cultural, economic and social factors; the configuration of the treatment scheme, with primary decanter, aeration tank and secondary decanter; compliance with the legislation in force in Portugal and Brazil for discharge into water courses; and application of the activated sludge model, ASM1, using the GPS-X 6.0 program for the simulations. Thus, a total of 864 simulations were performed, divided into 4 scenarios, covering small to large WWTP, with a population of 10,000 to 200,000 inhabitants, with 8 conditions from A to H. Thus, changes were made in temperatures, flows and polluting loads (BOD5 and SST) for years zero, ten and twenty. In the configuration of the treatment system, 3 levels were considered for the aeration operation, sludge recirculation and sludge purge in the decanters based on QMÍN, QMÉD and QPTA. In the case of the aeration tank, in which 2 aeration systems were studied: with diffusers and surface agitators, the diffusers had a lower power requirement. The choice of the optimal alternative for each scenario was defined based on the results that presented better quality in the final effluent and lower costs in aeration, recirculation and sludge treatment. In Portugal, where there are higher capitation and lower concentrations of pollutants than in Paraná, condition B (circular decanters) is higher than to the others for the first three scenarios, except in scenario 4 where condition D, with rectangular units, proved to be the best choice. In Paraná, the rectangular format with condition F proved to be the best option for scenarios 1, 2 and 3, and in scenario 4 the circular geometry was the most efficient.
Description
Trabalho Final de Mestrado para a obtenção do grau de Mestre em Engenharia Civil, área de especialização de Hidráulica
Keywords
Águas residuais urbanas ETAR Lamas ativadas Modelação ASM1 GPS-X Urban wastewater WWTP Activated sludge Modeling
Citation
FERNANDES, Otavio Felipe – Modelação de sistemas de tratamento biológico com lamas ativadas para águas residuais urbanas. Lisboa: Instituto Superior de Engenharia de Lisboa, 2021. Dissertação de Mestrado.
Publisher
Instituto Superior de Engenharia de Lisboa