Deciphering three-dimensional bioanode configuration for augmenting power generation and nitrogen removal in air–cathode microbial fuel cells.

[Display omitted] • Two 3D carbon felt anodes with engineering mesoscale structure are fabricated. • Power density and columbic efficiency are increased with the 3D anodes processing. • The active 3D anode biofilm is consisted of a number of functional bacteria. • The increased anode biomasses are achieved by using the 3D anodes. In this study, the engineering-oriented three-dimensional (3D) bioanode concept was applied, demonstrating that spiral-stairs-like/rolled carbon felt (SCF/RCF) configurations achieved good performances in air–cathode microbial fuel cells (ACMFCs). With the 3D anodes, ACMFCs generated significantly higher power densities of 1535 mW/m3 (SCF) and 1800 mW/m3 (RCF), compared with that of a traditional flat carbon felt anode (FCF, 315 mW/m3). The coulombic efficiency of 15.39 % at SCF anode and 14.34 % at RCF anode also is higher than the 7.93 % at FCF anode. The 3D anode ACMFCs exhibited favorable removal of chemical oxygen demand (96 % of SCF and RCF) and total nitrogen (97 % of SCF, 99 % of RCF). Further results show that three-dimensional anode structures could enrich more electrode surface biomass and diversify the biofilm microbial communities for promoting bioelectroactivity, denitrification, and nitrification. These results demonstrate that three-dimensional anodes with active biofilm is a promising strategy for creating scalable MFCs-based wastewater treatment system. [ABSTRACT FROM AUTHOR]