Caracterização respirométrica da microbiota de um sistema de lodo ativado com aeração prolongada.

• Autor(a) principal: Paes, João Felipe Brandão Castanho
• Data de Publicação: 2018
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Ceará (UFC)
• Texto Completo: http://www.repositorio.ufc.br/handle/riufc/45597
• topic: Lodo ativado; Respirometria; Constantes cinéticas; Biodesfosfatação

Although the microscopic description of the activated sludge community has great importance for the evaluation of wastewater treatment plants (WWTP) conditions, the use of this practice is still incipient in Brazil, and the results are generally underutilized. In contrast, respirometry has proved to be a very accessible technique to evaluate reactions kinetics and verify the metabolic behavior of the microorganism species present in the biomass. Thus, in this study the respirometry technique was used to describe the microbiota of an activated sludge system with extended aeration of a sewage treatment plant that belongs to a company located in Fortaleza, Ceará by defining the kinetic constants of heterotrophic and autotrophic bacteria besides evaluating the activity of phosphorus accumulating organisms present in the sludge. In addition, the sludge cell decay process was evaluated. The substrates used were ethanol and sodium acetate for the heterotrophic, and ammonium chloride and sodium nitrite for the autotrophic ones. The temperature of the experiments was around 25°C, and the Monod model adapted by van Haandel was applied as a basis for calculating the biomass kinetic constants. The heterotrophic bacteria present in the sludge had higher affinity with ethanol than acetate, although the last one favored a higher growth rate, wich is compatible with other sludge from activated sludge systems with extended aeration. Regarding the autotrophic biomass, the kinetic constants values of the sludge were lower than expected. Nitrite oxidizing bacteria showed affinity to the substrate, allowing microbial growth even at low concentrations. Regarding the evaluation of the sludge phosphate biological removal process, the phosphorus accumulating bacteria presented low activity, indicating that the studied sludge has a low phosphorus removal capacity. Finally, the sludge is resistant to substrate scarcity, and its decay is slow. Most volatile suspended solids are possibly composed by inert material and does not have a good correlation with active sludge concentration (Xa).