Effect of Different Operating Conditions on MFC Performance

Abstract

Dual-chamber microbial fuel cells (MFCs) were established to study the effect of seed sludge, carbon sources, buffering solution and stirring on power generation performance. Scanning electron microscope (SEM) and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technologies were used to investigate the spatial distribution characteristics of bacterial community. The results showed that the MFC feeding with lactic acid obtained 0.57V of electromotive force, and 1.57 W/m3 of volumetric power density. It reached 0.62V and 2.07 W/m3 when the carbon source was changed to acetic acid. Compared with anaerobic sludge, aerobic sludge had higher maximum voltage and longer high voltage duration. The stirring and the adding buffer solution improved electricity generation. SEM and DGGE profiles indicated that a large number of bacilli were tightly bound to the anode surface. Microbial community structure on the membrane surface was more similar to suspended sludge than sediment and seed sludge. In conclusion, MFCs perform better with incubating aerobic sludge, feeding acetic acid, adding PBS buffer (50mmol/L) and stirring.

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“…A shortened lag time at the start period in the batch test was also observed. The improved electricity generation process with the help of the stirring operation was consistent with the previous report (Pham et al, 2008;Lu et al, 2013). This can be explained by the improved mass transfer in anode chamber under stirring condition, which facilitate the mixing of the microbes with the culture and increase the transfer rate of electrons (Pham et al, 2008;Lu et al, 2013).…”

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“…104,109 In addition, reactors inoculated with aerobic sludge have higher maximum voltages and longer high pressure durations than anaerobic sludge-inoculated reactors, which could be ascribed to the former containing a large number of facultative electrogenic bacteria. 47 Moreover, in three reactors inoculated with anaerobic sludge from a wastewater plant, rice paddy eld soil, and coastal lagoon sediment, the MFC inoculated with coastal lagoon sediment showed the highest performance in terms of the treatment time, and the results showed that the three different inoculum sources all contained functional electrical production groups, whereas different community members controlled the performances of the MFCs. 44 Therefore, it is concluded that the microbial constitution of the inoculum determines the BES performance.…”

“…45 However, the environmental media, especially soil or sediments, and the PEM or salt bridges have a huge internal resistance that hinders the transmission of protons, resulting in a proton transfer rate much lower than the anodic output rate and the cathodic consumption rate, thus producing a pH gradient from anode to cathode. 46,47 For example, proton accumulation occurred close to the anode, leading to the formation of an acid-alkaline transition zone from the anode to the cathode in a bioelectrochemical remediation system. 11 A suitable pH range is required for the survival of microorganisms, so the acid-base differentiation between the anode and cathode adversely affects the growth and activity of microorganisms.…”