Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2008. / Submitted by Diogo Trindade Fóis (diogo_fois@hotmail.com) on 2009-10-01T11:20:46Z
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Previous issue date: 2008-12-18 / O emprego de reatores UASB em estações de tratamento de esgotos no Distrito Federal vem sendo bastante difundido desde o início dos anos 1990, atendendo mais de um milhão de habitantes (POE/CAESB, 2005). Por outro lado, os problemas relativos ao manejo adequado do lodo produzido nos reatores ainda não foram suficientemente solucionados, gerando demandas crescentes de operação e manutenção. Ao avaliar a influência da operação de descarte de lodo no desempenho dos reatores UASB no DF, pretendeu-se determinar uma rotina eficiente de descarte de lodo que minimiza os problemas operacionais observados. Por meio da avaliação do desempenho dos reatores UASB da estação de tratamento de esgotos do Gama, submetidos a diferentes rotinas de descarte de lodo, buscou-se uma forma de generalização dos resultados para as demais estações de tratamento de esgotos do DF. Após monitoramento de dois reatores UASB da ETE Gama, avaliando os impactos da suspensão do descarte programado de lodo em uma das unidades, verificaram-se remoções médias de 69% de DQO, 86% de DBO e 58% para SST, superiores às observadas durante a operação regularmente adotada (DQO = 61%, DBO = 81%, SST = 44%). A análise estatística, por meio do teste t de Student, revelou que as duas modalidades de operação produziram efluentes de características distintas para DBO e DQO, nos níveis de 5 e 10% de significância e semelhantes para SST e sólidos sedimentáveis, apenas no nível de 5%. Observou-se que o excesso de escuma superficial é preocupante, podendo ter origem no fraco desempenho do tratamento preliminar e na ausência de uma estratégia de descarte de lodos bem definida. Utilizando uma metodologia proposta para amostragem do lodo e da escuma, foi definida uma rotina de periodicidade mensal para os descartes de lodo nos reatores. São ainda sugeridas alterações de projeto nos sistemas de descarte de escuma e para amostragem de lodo nos reatores UASB, buscando reduzir os gastos operacionais e de manutenção das unidades. _______________________________________________________________________________ ABSTRACT / The use of UASB reactors as units of sewage treatment plants (STP) in the Federal District, Brazil, has been much disseminated since the beginning of the years 90, receiving sewage from more than a million inhabitants (POE/CAESB, 2005). On the other hand, the problems related to the appropriate handling of the sludge produced in the UASB reactors were not yet completely solved, generating growing demands on operation and maintenance. When evaluating the local influence of the operation of sludge discard in the UASB reactors’ performance, it was intended to determine an efficient routine of sludge discard for minimizing the observed operational problems. Through the evaluation of the performance of the UASB reactors existing in the Gama sewage treatment plant, which were submitted to different routines of sludge discard, it was searched for a generalization of these results for other sewage treatment plants in the Federal District. Monitoring two UASB reactors in the Gama STP to evaluating the impacts of stopping the intentional discard of sludge in one of the units, it was verified removal efficiencies of 69% for COD, 86% for BOD, and 58% for TSS, which were higher than the observed ones during the regular operation (COD = 61%, BOD = 81%, TSS = 44%). The statistical analysis, using the Student test, showed that the two modalities of UASB reactors operation had produced effluents with distinct characteristics for BOD and COD, in the 5 and 10% significance levels, and that they were similar for SST and Settable Solids, only in the 5% significance level. It was observed that the excess of superficial scum is a problem, which may have its origin in the poor performance of the preliminary treatment and in the absence of a well defined strategy of sludge discard. Employing the proposed methodology for sampling the sludge and the scum inside the UASB reactors, an operational routine of monthly regularity for the sludge discards has been defined for the UASB reactors. Also, project alterations in the systems of discarding of scum and for sampling of sludge in the UASB reactors were suggested, looking for reducing the operational and maintenance expenses.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.unb.br:10482/3592 |
| Date | 18 December 2008 |
| Creators | Ramos, Ricardo Augusto |
| Contributors | Souza, Marco Antonio Almeida de |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UnB, instname:Universidade de Brasília, instacron:UNB |
| Rights | info:eu-repo/semantics/openAccess |
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