Effect of HRT and external resistances on power generation of sidestream microbial fuel cell with CNT-coated SSM anode treating actual fermentation filtrate of municipal sludge

A microbial fuel cell (MFC) with multiwall carbon nanotube (CNT) coated stainless steel mesh (SSM) coated anode (S-MFC) was operated with a filtrate generated by the fermentation of municipal primary sludge. The S-MFC's maximum power density (MPD: 69.8-164.9 W/m(3)) and energy recovery (ER: 0.15-0.60 kWh/kgCOD) were 7-21 times higher than those (3.8-27.3 W/m(3) and 0.01-0.11 kWh/kgCOD) of MFC with a graphite felt as an anode (G-MFC). The microbial communities of S- and G-MFCs varied slightly depending on the electrode material. Chloroflexi (23.5%) was dominant in S-MFC, and Proteobacteria (25.3%) in G-MFC. Fermenting bacteria such as Rhodanobacter lindaniclasticus and Anaerolineaceae bacterium were dominated by continuous non-electrochemically active bacteria invasion because the actual fermentation filtrate was directly utilized as the substrate. Nevertheless, the CNT-coated SSM anode and the fermentation filtrate of primary sludge improved the power generation in MFC, which demonstrates the significant potential of this sidestream process for sludge treatment. (C) 2019 Elsevier B.V. All rights reserved.