Degradação de matéria orgânica e inativação de coliformes totais em efluente anaeróbio por ozonização em reator Air-lift
The treatment of sanitary sewage is a matter of extreme importance due that in Brazil, only 40.8% of the sewage generated is adequately treated. In Brazil about 80% of the WWTPs use anaerobic digestion for the treatment of sewage, and only 21.8% of the WWTPs have pathogen disinfection systems. Thus,...
| Autor principal: | Pereira, Thiago Castanho |
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| Formato: | Trabalho de Conclusão de Curso (Graduação) |
| Idioma: | Português |
| Publicado em: |
Universidade Tecnológica Federal do Paraná
2020
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| Assuntos: | |
| Acesso em linha: |
http://repositorio.utfpr.edu.br/jspui/handle/1/9145 |
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| Resumo: |
The treatment of sanitary sewage is a matter of extreme importance due that in Brazil, only 40.8% of the sewage generated is adequately treated. In Brazil about 80% of the WWTPs use anaerobic digestion for the treatment of sewage, and only 21.8% of the WWTPs have pathogen disinfection systems. Thus, ozonation processes can be implemented to carry out the post-treatment and disinfection of anaerobic effluents. However, one of the limitations of the process is the mass transfer of the ozone at the gas-liquid interface. Replacement of bubble column reactors by air-lift reactors brings significant improvements in mass transfer. The present work had as objective to evaluate the ozonation process of anaerobic effluent, having as response variables the degradation of organic matter and inactivation of total coliforms. For the development of this paper, a central rotational compound design (DCCR) was used, using pH and time of contact as factors. Tests were carried out at pH 4; 4.9; 7; 9.1 and 10; and contact times ranging from 15 to 60 minutes. The degradation of organic matter was verified through Chemical Oxygen Demand (COD), Total Organic Carbon (TOC) and UVVis and Fluorescence spectroscopy. The inactivation of total coliforms and Escherichia coli was analyzed by performing cultures on chromogenic substrate and counting the most probable number (MPN) by the Colilert® Quanti-Tray® method. The experiments demonstrated a higher organic matter removal efficiency at pH 9.1 at a contact time of 56 minutes, achieving a 54% removal in terms of COD. The degradation of aromatic organic matter was observed through UV-Vis scanning spectra and emission and excitation matrices using fluorescence spectroscopy. The mass transfer of the ozone to the liquid medium obtained an average of 90%, with a maximum of 95% in the tests at pH 4. The inactivation of total coliforms reached an efficiency of 99.7% representing a decrease of 2.5 log units. The removal of E. coli showed an efficiency of 99.7%, with a decrease of 2.3 log units. In this way, it was possible to verify the efficiency of the air-lift reactor in the mass transfer and the efficiency of the ozonation in the removal of organic matter, aromatic compounds, and inactivation of bacteria. |
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