Análise microbiológica como controle de qualidade de processo aeróbio alimentado por efluente de reator UASB

• Autor(a) principal: Oliveira, Michelli Ferreira de
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: https://ri.ufs.br/jspui/handle/riufs/14058
• topic: Microbiota; Oxidação; Tratamento biológico; Processo combinado; Estação de tratamento; Civil engineering; ENGENHARIAS::ENGENHARIA CIVIL

The study of the microbiota that composes the biological wastewater treatment systems allows analysis of operating conditions and effluent quality, since microorganisms are highly sensitive to small variations in the environment. So, this work aimed to characterize the microbial community present in the combined system’s aeration tank, consisting of a UASB reactor followed by an oxidation ditch, used at the Wastewater Treatment Plant (WWTP) of the Federal University of Sergipe. Physical-chemical parameters of the WWTP were monitored and qualitative and quantitative microbiological examinations of the mixed liquor were carried out to evaluate the microbiota of the oxidation ditch. As a result, 39 bacterial isolates were obtained, which were subsequently evaluated in terms of protein profiles by MALDI-TOF, where 13 distinct genera that are characteristic of sewage treatment systems were identified. The predominant genus of bacteria were Acinetobacter, Bacillus, Enterococcus and Enterobacter. It was possible to infer that 63% of the identified bacteria are facultative and only 37% are aerobic. Genus of bacteria identified are very important for the treatment because they have properties of removing organic matter, nutrients and structuring biomass. The average number of heterotrophic bacteria found in the system was 9.40 x 107 CFU/mL. Few protozoa and metazoans were found due to the diluted samples collected. The temperature of the samples was in the range of 24 a 32oC considered optimal for bacterial activities and the pH values varied from neutral to slightly alkaline. The DO concentrations in the oxidation ditch varied from 0.6 and 0.8 mg/L, before the aerators were turned on, and between 1.7 and 4.4 mg/L, after being turned on. At the WWTP, the average efficiency of COD removal was 30%, while efficiency of total solids was 9%. These values are lower than that found in the literature for combined systems. The low frequency and diversity of microorganisms observed during the microscopic analysis indicate that the polishing of the treated effluent by these organisms is not being carried out properly, reducing the efficiency of the treatment. The correlation analysis between the microbiological and physical-chemical parameters indicated that there was a moderate positive correlation with the concentrations of DO and solids. Thus, it’s possible to infer these parameters influence the number of bacteria present in the mixed licour. So, it was concluded that the operational conditions of the WWTP influence the microbiological community found in this study. In addition, the amount of bacteria found and the low frequency of the appearance of protozoa and metazoans demonstrated that the efficiency of organic matter removal in the system is unsatisfactory.