The performance of microbial anodes in municipal wastewater: Pre-grown multispecies biofilm vs. natural inocula.

In this study, different inoculation strategies for continuously operated microbial anodes are analyzed and compared. After 20daysof operation with municipal wastewater anodes pre-incubated with a biofilm of the exoelectrogenic species Geobacter and Shewanella showed current densities of (65±8) μA/cm ² . This is comparable to the current densities of non-inoculated anodes and anodes inoculated with sewage sludge. Analysis of the barcoded pre-grown multispecies biofilms reveal that 99% of the original biofilm was detached after 20daysof operation with municipal wastewater. This is in contrast to previous experiments where a pre-grown biofilm of exoelectrogens was operated in batch mode. To implement pre-grown biofilms in continuous systems it will thus be necessary to reveal a window of process parameters in which typical exoelectrogenic microorganisms including model organisms can be kept and/or enriched on anodes.
(Copyright © 2016. Published by Elsevier Ltd.)