Transferência de metano no sentido gás-líquido com vistas ao atendimento da demanda carbonácea da desnitrificação de esgoto sanitário


IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia




This work presents a simulation of a hybrid system for waste water treatment, in order to explain the possible use of a carbon supply on denitrification from the methane produced in an anaerobic reactor and transferred to the liquid mass of a reactor that would be removing nitrogen. It was used the biogas produced in a UASB reactor, that passed through a storage and purifying process so its quality meets the requirements needed to the following trials. As a satisfactory quality was attained (reduction of 88% of CO2 and total elimination of H2S) the gas to liquid mass transference trials were started. The main goal was to evaluate the methane income to the liquid phase of the denitrification reactor. The increase of the biogas application rate led to an increase of the volumetric transfer coefficient values - KLa (12,63h-1, 18,16h-1 e 22,9h-1 for application rates of 10,7, 15,3 and 22,4 m3/m2.h respectively) and the Specific Transfer Rate STR (1,33g/h, 1,87g/h and 2,56g/h for application rates of 10,7, 15,3 e 22,4 m3/m2.h respectively), while there was a decrease of the Specific Transfer Efficiency - STE (13,83%, 13,63% and 11,63% for application rates of 10,7, 15,3 e 22,4 m3/m2.h respectively). It was also observed that the height of the water column (more specifically the position of the sample point in the reactor column) cause an influence in the response of the kinetic transfer parameters. This influence was related to the rising bubbles dynamics, especially to their coalescence. Once we had the data on the kinetics of methane transfer in the denitrification reactor, the inquiry on the carbon supply in the methane coupled to denitrification (process ME-Ds) started. The two main questions were: 1) does the system allows the capture of enough carbon as CH4 in order to fulfill the demand of carbon required in the ME-Ds processes? 2) Does the transfer rate of this carbon to the liquid phase of the reactor is capable to sustain the expected denitrification rates? It was verified that even when the quantity of carbon captured in enough, the maintenance of denitrification rates in a satisfactory level is limited due to the specific transfer kinetics. The preliminary conclusion of this research is that the denitrification of methane could be viable in a laboratory, but a waste water treatment based on ME-D technology would hardly be self-sustainable


biogás, relação c/n biogas desnitrificação acoplada ao uso de metano suplemento carbonáceo esgotos carbonic supplement mass transfer c/n relation transferência de massa methane coupled to denitrification engenharia sanitaria

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