RESUMO
A very compact flat microbial fuel cell (MFC), with 64 cm2 each for the anode surface and the cathode surface and 1 cm3 each for the anode and cathode chambers, was tested for wastewater treatment with simultaneous electricity production with the ultimate goal of implementing an autonomous service in decentralized wastewater treatment systems. The MFC was operated with municipal wastewater in sequencing batch reactor mode with re-circulation. Current densities up to 407 W/m3 and a carbon removal of 83% were obtained. Interruption in the operation slightly decreased power density, while the re-circulation ratio did not influence power generation. The anode biofilm presented high conductivity, activity and diversity. The denaturing gradient gel electrophoresis band-pattern of the DNA showed the presence of several ribotypes with different species of Shewanellaceae and Geobacteraceae families.
Assuntos
Fontes de Energia Bioelétrica/microbiologia , Eliminação de Resíduos Líquidos/instrumentação , Eliminação de Resíduos Líquidos/métodos , Biofilmes , Carbono/química , Eletroforese em Gel de Gradiente Desnaturante , Condutividade Elétrica , Ferro/química , Viabilidade Microbiana , Microscopia Confocal , Águas Residuárias/química , Águas Residuárias/microbiologiaRESUMO
Recent studies reporting on the useful implementation of fungi in wastewater treatment plants triggered the need to improve fungi based systems. Therefore, it is crucial to investigate the conditions that promote their selection. The present work aims to study the effect of the organic loading rate on the growth of filamentous fungi. Three sequencing batch reactors (SBR), fed with an easily biodegradable substrate (acetate), were operated at different organic loading rates: 4.3 g COD L(-1) day(-1) (SBR1), 1.0 g COD L(-1) day(-1) (SBR2) and 0.5 g COD L(-1) day(-1) (SBR3). High amounts of fungal filaments were observed in the SBR operating at higher organic loading rate, as ascertained by direct microscopic inspection, while, at lower organic loading rates, overabundance of fungal filaments was not observed. Sequence retrieved from the isolated fungal filaments presented high similarity (99 %) to Galactomyces geotrichum.
