A new upgraded biogas production process: Coupling microbial electrolysis cell and anaerobic digestion in single-chamber, barrel-shape stainless steel reactor

Enhanced methane production in an anaerobic digestion and microbial electrolysis cell coupled system with co-cultivation of Geobacter and Methanosarcina

“…1b). The maximum COD removal rate in the AD-MEC-G reactor (216.8 mg COD/(L·hr)) was enhanced by 29.6% compared to our previous study (AD-MEC system) of 167.3 mg COD/(L·hr) (Bo et al, 2014).…”

“…1a, the cumulative methane volume in the AD-MEC-G system achieved 642.9 mL in 72 hr, showing a methane yield of 360.2 mL/g-COD, which was increased by 59.7% and 32.4% compared to the AD (225.5 mL/g-COD) and AD-G (272.7 mL/g-COD) reactors, respectively. The result is also higher than that obtained in an AD-MEC reactor (289.6 mL/g-COD) (Bo et al, 2014). We obtained a 24.1% increment by co-cultivating Geobacter and Methanosarcina.…”

“…Moreover, Fig. 1d shows that hydrogen gas was detected in the AD-MEC-G reactor, which has been proved to drive carbon dioxide to methane conversion in AD-MEC systems (Bo et al, 2014). In addition, a recent study showed that with the presence of Geobacter, DIET becomes an important way for methane production in bioelectrochemical systems (Zhao et al, 2015).…”

“…A new technology which couples an anaerobic digester (AD) with a microbial electrolysis cell (MEC) has been developed to increase the production and purity of biogas simultaneously (Bo et al, 2014;Cheng et al, 2009;Logan and Rabaey, 2012). Our previous study demonstrated that redundant carbon dioxide produced from AD can be in situ converted to additional methane by electromethanogens utilizing hydrogen formed from MEC as an electron donor, generating high quality biogas (Bo et al, 2014).…”

“…In recent years, Geobacter has been observed to be able to directly transfer electrons to methanogens, such as Methanosaeta and Methanosarcina, to reduce carbon dioxide to methane Reguera et al, 2005;Rotaru et al, 2014a,b;Zhao et al, 2015). Generally, carbon dioxide reduction to methane is processed via sequential pathways: electron to proton transfer, hydrogen formation and carbon dioxide reduction (Bo et al, 2014). The new pathway (direct interspecies electron transfer, DIET) without the step of hydrogen formation is apparently more efficient than the traditional pathway.…”