Tecnologias de baixo custo para tratamento de esgoto rural: reator UASB e fossa séptica econômica
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Data
2018-12-10
Autores
Franceschini, Guilherme
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Universidade Estadual Paulista (Unesp)
Resumo
A falta de tratamento de esgoto sanitário ainda é um dos principais problemas socioambientais da população brasileira, principalmente no contexto dos moradores da zona rural, onde há grande déficit de cobertura. A partir dessa realidade, buscou-se na literatura experiências de sistemas de baixo custo que contemplassem a demanda para o tratamento de esgoto unifamiliar. Identificou-se que as experiências existentes, principalmente no Brasil, são pouco relatadas frente à grande demanda por este tratamento. Neste sentido, a presente pesquisa teve o objetivo de avaliar a eficiência de duas tecnologias de baixo custo para o tratamento de esgoto unifamiliar, a Fossa Séptica Econômica (FSE) e o reator anaeróbio de fluxo ascendente (RAFA ou, em inglês, Upflow Anaerobic Sludge Blanquet, UASB), tendo em vista identificar vantagens e desvantagens de suas aplicações. Foram realizadas análises laboratoriais de amostras do afluente e da saída dos sistemas. Primeiramente os dados foram analisados de forma descritiva, por meio de gráficos e medidas resumo. Para avaliar a eficiência foi realizado o teste t – student e obtidos os intervalos de confiança. Tanto a FSE como o reator UASB evidenciaram-se com desempenho satisfatório quando comparados aos tanques sépticos convencionais, que seguem os parâmetros de dimensionamento da norma brasileira, e com reatores UASB operando com vazões maiores. Para a FSE que tratou todas as águas residuárias de uma residência, com exceção da máquina de lavar roupas, as eficiências de remoção para os parâmetros SST, DBO5 e DQO foram de 77,0 ± 23,7%, 58,4 ± 22,1% e 63,0 ± 22,9%, respectivamente. Já a FSE que tratou apenas água negra, teve eficiências de remoção de SST, DBO5 e DQO de 76,2 ± 18,9%, 55,3 ± 19,2% e 60,0 ± 15,6, respectivamente. O reator UASB, que também tratou apenas água negra, apresentou eficiências de remoção de SST, DBO5 e DQO de 77,8 ± 17,5%, 57,2 ± 19,0 e 50,0 ± 21,7%, respectivamente. Espera-se que o presente estudo contribua para a divulgação destas tecnologias que, devido ao seu caráter de baixo custo (e a FSE uma tecnologia social), fazem-se promissoras alternativas a serem incorporadas nas ações de políticas públicas voltadas ao tão deficitário serviço de saneamento básico nas diferentes configurações rurais de nosso país.
The lack of sanitary sewage treatment remain one of the main socio-environmental problems of the Brazilian population, especially in the context of rural dwellers, where there is a huge deficit of coverage. From this reality, we searched in the literature experiences of low cost systems that contemplated the demand for the treatment of single-family sewage. It was identified that the existing experiences, mainly in Brazil, are little reported in face of the great demand for this treatment. In this sense, the present research had the objective of evaluating the efficiency of two low-cost technologies for the treatment of single-family sewage, the Fossa Séptica Economica (FSE) and the Upflow Anaerobic Sludge Blanquet (UASB), in order to identify the advantages and disadvantages of their applications. Laboratory analyzes of tributary and outlet samples were performed. First, the data were analyzed in a descriptive way, by means of graphs and summary measures. To evaluate the efficiency, the student T test was performed and the confidence intervals were obtained. Both the FSE and the UASB reactor showed satisfactory performance when compared to conventional septic tanks, which follow the design parameters of the Brazilian standard, and with UASB reactors operating at higher flow rates. For the ESF that treated all household wastewaters, except for the washing machine, the removal efficiencies for the SST, BOD5 and COD parameters were 77.0 ± 23.7%, 58.4 ± 22.1% and 63.0 ± 22.9%, respectively. The FSE, which treated only black water, had SST, BOD and COD removal efficiencies of 76.2 ± 18.9%, 55.3 ± 19.2% and 60,0 ± 15.6, respectively. The UASB reactor, which also treated only black water, presented efficiencies of removal of SST, BOD5 and COD of 77.8 ± 17.5%, 57.2 ± 19.0 and 50.0 ± 21.7%, respectively. It expected that the present study to contribute to the dissemination of these technologies, which, due to their low cost nature (and the FSE a social technology), are promising alternatives to be incorporated in public policy actions directed at the sanitation in the different rural settings of our country
The lack of sanitary sewage treatment remain one of the main socio-environmental problems of the Brazilian population, especially in the context of rural dwellers, where there is a huge deficit of coverage. From this reality, we searched in the literature experiences of low cost systems that contemplated the demand for the treatment of single-family sewage. It was identified that the existing experiences, mainly in Brazil, are little reported in face of the great demand for this treatment. In this sense, the present research had the objective of evaluating the efficiency of two low-cost technologies for the treatment of single-family sewage, the Fossa Séptica Economica (FSE) and the Upflow Anaerobic Sludge Blanquet (UASB), in order to identify the advantages and disadvantages of their applications. Laboratory analyzes of tributary and outlet samples were performed. First, the data were analyzed in a descriptive way, by means of graphs and summary measures. To evaluate the efficiency, the student T test was performed and the confidence intervals were obtained. Both the FSE and the UASB reactor showed satisfactory performance when compared to conventional septic tanks, which follow the design parameters of the Brazilian standard, and with UASB reactors operating at higher flow rates. For the ESF that treated all household wastewaters, except for the washing machine, the removal efficiencies for the SST, BOD5 and COD parameters were 77.0 ± 23.7%, 58.4 ± 22.1% and 63.0 ± 22.9%, respectively. The FSE, which treated only black water, had SST, BOD and COD removal efficiencies of 76.2 ± 18.9%, 55.3 ± 19.2% and 60,0 ± 15.6, respectively. The UASB reactor, which also treated only black water, presented efficiencies of removal of SST, BOD5 and COD of 77.8 ± 17.5%, 57.2 ± 19.0 and 50.0 ± 21.7%, respectively. It expected that the present study to contribute to the dissemination of these technologies, which, due to their low cost nature (and the FSE a social technology), are promising alternatives to be incorporated in public policy actions directed at the sanitation in the different rural settings of our country
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Palavras-chave
Tecnologia social, Tratamento de esgoto unifamiliar, Baixo custo, Tratamento de esgoto rural, Baixa vazão