Direct interspecies
electron transfer (DIET) is a breakthrough
that can surpass the limitations of anaerobic digestion. Conductive
materials and polarized bioelectrodes are known to induce DIET for
methane production but are still challenging to apply at a field scale.
Herein, compared to polarized bioelectrodes, electrostatic fields
that promote DIET were investigated in an anaerobic reactor with conductive
materials. As a conductive material, activated carbon enriched its
surface with electroactive microorganisms to induce DIET (cDIET).
cDIET improved the methane yield to 254.6 mL/g CODr, compared
to the control. However, polarized bioelectrodes induced electrode-mediated
DIET and biological DIET (bDIET), in addition to cDIET, improving
the methane yield to 310.7 mL/g CODr. Electrostatic fields
selectively promoted bDIET and cDIET for further methane production
compared to the polarized bioelectrodes. As the contribution of DIET
increased, the methane yield increased, and the substrate residue
decreased, resulting in a significant improvement in methane production.