Improved performance of CEA microbial fuel cells with increased reactor size

Abstract

The performance of an over 10 times larger microbial fuel cell (MFC) with double cloth electrode assemblies (CEAs) during 63 days of continuous operation demonstrates that the excellent performance of CEA-MFCs can be further improved during scale-up. With a new separator material and U-shaped current collectors, the larger MFC produced a maximum power density of 4.30 W m À2 at a current density of 16.4 A m À2 , corresponding to a volumetric power density of 2.87 kW m À3 at 10.9 kA m À3 for a double CEA-MFC. The high current density led to a high average coulombic efficiency (CE) of 83.5% as well as a high potential COD removal rate of 93.5 kg m À3 d À1 . Energy efficiency is estimated in the range of 21-35%, depending on the operating voltage. The low-cost non-woven cloth separator further reduced the anode-cathode spacing and internal resistance, greatly enhancing the power generation. The enhanced self-production of bicarbonate buffer, which can be manipulated by adjusting hydraulic retention time and substrate concentration, also contributed to the improved performance. The results demonstrate the great potential of MFC technology in competing with methanogenic anaerobic digestion for waste-to-electricity and wastewater treatment.

Extracellular Electron Transfer Mediated by Flavins in Gram-positive Bacillus sp. WS-XY1 and Yeast Pichia stipitis

“…The presence of a certain amount of oxygen in anode chamber was reported to enhance the performance of microbial fuel cells [24,25]. In this work, we isolated functional microbes from micro-aerobic anode chamber to elucidate their electron transfer mechanism.…”

Microbial fuel cells for energy production from wastewaters: the way toward practical application

“…This makes it hard to realize the energy and economic revenues. Although a maximum volumetric power density of 2.87 kW/m 3 (normalized to the fuel cell volume) has been achieved in a 30 ml MFC with a cloth electrode assembly configuration (Fan et al, 2012), the value decreased substantially (typically to less than 35 W/m 3 ) when the fuel cell size was increased from milliliter-scale to liter-scale (Dekker et al, 2009). It has been suggested that MFCs should have to be able to produce at least 400 W/m 3 to be competitive with traditional anaerobic digestion , and to have an output of 1 kW/m 3 (at an organic loading rate of 10 kg-COD/(m 3 •d)) to achieve energy self-sufficiency (Rabaey and Verstraete, 2005).…”

“…From the economic point of view, expensive membranes, such as ion exchange membranes, ultra filtration membranes, and forward osmosis membranes are not suitable for use in large-scale MFCs. A promising low-cost separator material is non-woven cloth (Fan et al, 2012;Wang et al, 2013), but its mechanical strength and long-term stability still need to be improved. The development of low cost, proton transferable, and long-term stable separator materials is very important for large-scale MFCs in the future.…”

“…Low-cost cloths have been recommended to replace expensive membranes as an effective separator for large-scale applications. A cloth-electrodes assembly configuration has proved to enable reducing the anode-cathode spacing to 0.6 mm while greatly enhancing power generation (Fan et al, 2012). However, cloths may gradually be degraded by the microorganisms in the system, thus impairing the long-term stability of MFCs.…”

Célula Combustível Microbiana Usada Para Geração De Energia Elétrica a Partir De Lodo De Esgoto E Tensoativos Aniônicos

“…Uma possível fonte de energia renovável a ser empregada é a implementação de célula combustível microbiana (CCM), pois dentre suas aplicações destacamse exemplos relacionados à geração de energia elé-trica a partir do tratamento de águas residuárias ((DU;GU, 2007), (GHANGREKAR;SHINDE, 2007) e (FAN;HAN;LIU, 2012)). Esses sistemas podem ser operados com diferentes substratos, devido a flexibilidade dos micro-organismos que se utilizam destes substratos, de modo a degradá-los para a subsequente geração de eletricidade a partir de resíduos e biomassa ((ZHANG et al, 2009)).…”