PERFORMANCE EVALUATION AND IDENTIFICATION OF EXOELECTROGENS IN TWO TYPES OF MICROBIAL FUEL CELLS WITH DIFFERENT ANODE CONFIGURATION

Two microbial fuel cells (MCC) type PEM (proton exchange membrane) with different configuration at the anode were compared. The respective microbial samples which were isolated in order to identify the types of bacteria by amplification 16S gene. Sequencing of two clones showed the presence of alpha and beta proteobacteria as exoelectrogens. Such bacteria have been previously identified in activated sludge. The systems were operated in batch and mesophilic temperature intervals. CCM1 and CCM2 used carbon paper and granular graphite anodes, respectively. The substrate used was synthetic wastewater (ARS), containing glucose as carbon source, as well as using a mixed inoculum as biocatalyst; in the cathode chamber an O-2 saturated aqueous solution was used. The power density in CCM1 was 6W/m(3), with a COD (chemical O-2 demand) removal of 70%, while in CCM2 the observed average power density was similar to 48W/m(3) with a 95% COD removal. Both systems were evaluated during 120 days, the organic load was 4.7kg DQO/m3 per day and the HRT (hydraulic retention time) was of 24h.