Single-chamber microbial fuel cells as on-line shock-sensors for volatile fatty acids in anaerobic digesters.

In anaerobic digesters (AD), volatile fatty acids (VFAs) concentration is a critical operative parameter, which is usually manually monitored to prevent inhibition of microbial consortia. An on-line VFAs monitoring system as early-warning for increasing concentrations would be of great help for operators. Here, air-cathode membraneless microbial fuel cells (MFCs) were investigated as potential biosensors, whose electrical signal instantaneously moves from its steady value with the accumulation of VFAs in the anodic solution.