Desidratação térmica de lodo de esgoto através da queima do biogás : metodologia para ETE's de pequeno porte
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Data
2015-02-10
Autores
Girondoli, Ludimila Marvila
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Universidade Federal do Espírito Santo
Resumo
Currently the choice of Sewage Treatment Plant (STP) typology should consider the technological, economic and community requirements. Research solutions that seek sustainability is required in the process of sewage treatment, mainly related to waste generated in the process. In this conception, the association of biogas as a heat source for the treatment of sludge, both waste generated in UASB, becomes an alternative to be explored since there is no effective application of this association in Brazilian sanitation companies, especially in small STP. The objective of the study was to evaluate the feasibility of thermal dewateringthrough burning biogas on the dryingbed, to reduce moisture and pathogen’s concentration of biological sludge made in small STP. Having as a study case the STP from Piaçu. Sludge samples were collected and analyzed over 21 days of drying to the parameters: moisture, total solids, volatile solids, fecal coliform, viable helminths eggs and Salmonella sp infour repetitions, during the months of June to September, 2014. In relation to moisture , the values found for the bed with burning biogas (average 15%) was significantly lower than those bed of without burning (mean 28.3%). For microbiological parameters, there was the inactivation of viable helminths eggs, fulfilling the standard limited by 357/2006 Resolution of Conama. However, for Salmonella sp and fecal coliform parameters, the heat from the burning of biogas was not enough to raise the sludge mass temperature and promote the lethality of these microorganisms in order to fulfill the Resolution. With the methodology adopted it was found that there would be a reduction of about 80% of the costs with adequate sludge disposal of Piaçu STP and the financial return on investment would be achieved in about 4 years. However, the methodology adopted in this study for dewatering the sludge through the heat from the burning of biogas, showed satisfactory results being an alternative technique, environmentally andeconomically viable of energy use of biogas for small STP.
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Sewage sludge , Thermal dewatering , Sustainability , Biogas , Lodo de esgoto , Desidratação térmica