Stacked-MFC into a typical septic tank used in public housing

ABSTRACT

To test the viability of incorporating a stacked-microbial fuel cell (SMFC) within a typical septic tank, 15 cartridges of MFCs with proton exchange membrane without catalysts were installed in a real system considered with a pretreatment. Both chemical oxygen demand (COD) removal and electricity generation using super capacitors by electricity storage were investigated under continuous flow mode. Three MFCs A1, B4 and C2 with 109.40 ± 34.25 mW/m³, 131.58 ± 27.75 mW/m³ and 124.01 ± 27.57 mW/m³, respectively, were chosen for testing. The organic loading rate was 0.24, 0.52 and 1.05 kg DQO/m³-d corresponding to 200, 500 and 1000 ppm. Total COD removal and total coulombic efficiency were 89.67 ± 5.19% and 48.07 ± 2.33%. The results of this study suggest that MFCs may be suitable for deployment in a septic tank. This research has demonstrated the great challenges in applying a stack of MFC in scale-up. R_int showed that anode resistances are higher than cathode; however, the configuration seems to be indicated for this kind of system depuration in developing countries. An electrochemical model must be developed for scale up which explains performance and electrochemical data. It is necessary to develop experiments in scale up and to test the feasibility of implementation.

KEYWORDS:

• stacked-microbial fuel cells
• scale-up
• septic tank

Acknowledgements

Support for this work was provided by the Mexican Council for Science and Technology (CONACYT) grant to carry out this study through the projects CONAVI-101284, Basic Science-106416, FINNOVA-217189 and by the scholarship 41777 awarded for master's studies.

Disclosure statement

No potential conflict of interest was reported by the authors.