A batch-mode cube microbial fuel cell based “shock” biosensor for wastewater quality monitoring

A single chamber batch-mode cube microbial fuel cell (CMFC) was explored as a novel self-sustained biosensor for real-time monitoring the toxicity shocks (sudden change in toxins concentration) of representative toxic metals in wastewater influent. Four types of shocks, including chromium, iron, nitrate, and sodium acetate, were selected to represent the shocks of acute-toxic heavy metal, low-toxic metal, common nutrient, and organic contaminant in wastewater, respectively. Wastewater was used as the inoculum in CMFCs for anodic electrogenic bacteria that were fully acclimated within 3 days, which indicated that this self-powered sensor can be quickly adapted to wastewater. The results showed that the CMFC was able to distinguish shocks of toxins from non-toxins based on voltage signal changes. Anode open circuit potential (OCP) values were well correlated with the CMFC voltage changes, indicating that the voltage changes were mainly dependent on the activity of the electrogenic bacteria on the anode surfaces.