Avaliação da transferência de metano no sentido gás-líquido e da capacidade de suprimento da desnitrificação biológica de esgoto sanitário com doadores endógenos de elétrons (metano e sulfeto de hidrogênio)
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Data
2015-02-27
Autores
Morais, Thiago Nelo
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Universidade Federal do Espírito Santo
Resumo
This paper presents a simulation of the biological denitrification capacity of sewage through endogenous sources of electrons (methane and sulfide produced in their own treatment system) by simulating a hybrid treatment system. The present methane in the biogas produced in the anaerobic reactor can be used in the denitrification step through its transfer to the liquid phase. This transfer, however, has limitations that may compromise its use as the sole source of electrons. For this reason, one of the stages of this study aimed to evaluate the methane transfer capacity in the gas-liquid direction. The results demonstrate the increase in Specific Transfer Rate (STR) with increasing biogas application rate. However, this increase was not proportional, which implies a reduction in Specific Transfer Efficiency (STE) with increasing biogas application rate. In the second stage of the study, is simulated the use of the methane and sulfide produced in the anaerobic stage as electron donors for biological denitrification of wastewater in a hybrid system in seven different scenarios where they were exchanged important factors to the process. In all scenarios it considered the stoichiometric ratio via denitrifying in the simulation. When considering the possibility of providing all the recovered methane in the biogas to denitrification was achieved final effluent with zero levels of N-NO3 - . This consideration, however, leads to the overestimation of the potential use of this electron donor. The use of methane and sulfide dissolved in the effluent from the UASB reactor and recovered as methane and biogas can be effectively supplied to the system presented removal capacity of 13.8 mg.L -1 of N-NO3 - , 8.44 mg.L-1 of N-NO3 - and 6.42 mg.L -1 of N-NO3 - or 49.1%, 30.0% and 22.9% of N-NO3 - throughout the system, respectively, in the cancellation capability of nitrate levels the conditioned effluent used together these electron donors. Even if the relationship C/N and S/N are higher than those practices and could lead to stoichiometric limitations of the carrying capacity of the biological denitrification with endogenous sources of electrons, these sources can be used to reduce the need for exogenous donors electrons and thus the treatment costs, enhancing the promotion of the use of this technology in the treatment of sewage.
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Palavras-chave
methane , sulfide , mass transfer , biological denitrification , Gás-líquido , Desnitrificação , Metano , Sulfeto de hidrogênio , Esgotos , transferência de massa , desnitrificação biológica
Citação
MORAIS, Thiago Nelo. Avaliação da transferência de metano no sentido gás-líquido e da capacidade de suprimento da desnitrificação biológica de esgoto sanitário com doadores endógenos de elétrons (metano e sulfeto de hidrogênio). 2015. 96 f. Dissertação (Mestrado Profissional em Engenharia e Desenvolvimento Sustentável) - Programa de Pós-Graduação em Engenharia e Desenvolvimento Sustentável, Universidade Federal do Espírito Santo, Vitória, 2015.