Study of a commercial multipurpose cell as MFC with pure Geobacter S. biofilms and synthetic wastewaters

JUAN MANUEL ORTIZ; BEATRIZ MAESTRO; GERMÁN DAVID SCHROTT; PABLO SEBASTIÁN BONANNI; JUAN PABLO BUSALMEN; ANTONIO ALDAZ; VICTOR CLIMENT; JUAN FELIU

Congreso; Electron transfer at the microbe-mineral interface; 2012

Wastewaters are classically processed under anaerobic conditions in order to transform organic matter into acetate and short-chain organic acids, and then are further converted into methane through an additional treatment to be used as energy source. That process could be modified by replacing such a methanogenic stage by an advanced microbial fuel cell system able to convert acetate into electricity at high rate by means of electrogenic biofilms, so in these cases MFC constitute an attractive option to couple wastewater treatment and energy recovery.   Among the microorganisms suitable for these purposes, bacteria belonging to the genera Geobacter have been described regarding their direct electron exchange with electrodes. The anode reaction involves acetate oxidation CH3COO- + 2 H2O → 2 CO2 + 7 H+ + 8 e- , that is combined with a suitable cathodic reaction.   This work shows results obtained with a commercial multipurpose cell (E-Cell,  model MP, area section 100 cm2) modified to be used as MFC, inoculated with cultures of G. sulfurreducens grown in solutions containing 10 mM acetate (electron donor) and 40 mM fumarate (electron aceptor), in anaerobic conditions at 30 oC. The MFC was running with synthetic wastewater (Sodium Acetate 10-20 mM) as feed stream, at batch mode with recirculation, with different anode materials (carbon particles, carbon felt), and using Na2SO4 0.1 M (potentiostatic mode) or FeCl3 0.1 M (fuel cell mode) as catholyte solutions.