LAUSR

Abstract Microbial Electrolysis Cells (MECs) are often documented for their ability to produce hydrogen through new sources and new configurations. However, few studies attempt to document the recovery of the bioanode after being exposed to operational failure conditions. This study attempted to compare the behavior and recovery of MECs after being exposed to four operational failure conditions: acidification, oxygenation, osmotic shock, and voltage reversal. For each failure condition, three time points were tested: before failure, immediately after failure, and after recovery efforts. Of the modes tested, acidification suffered the largest loss in performance and operational efficiency immediately after acidification, while osmotic shock suffered the second largest loss in performance. Oxygenation and voltage reversal showed negligible signs of loss in performance immediately after failure conditions and after the recovery period. Failure had a minimal effect on the removal of individual compounds under aeration and voltage reversal conditions. However, acetate accumulated after acidification, and propionic acid accumulated after osmotic shock. The findings here could be useful for determining if failure will require more significant repair efforts in commercially deployed devices. While acidification created permanent losses to performance, if device failure like oxygenation, osmotic shock, and voltage reversal is caught early (less than 15 minutes), full recovery without bioanode replacement is likely.