Rapid warning of emerging contaminants in reuse water using biocathode sensors

The proliferation of emerging contaminants (ECs) in the environment poses a major threat to the safety of reuse water. However, many ECs exist for which no corresponding control standards have been established. Here, we used polarity reversal to construct a biocathode sensor capable of early warning of ECs biotoxicity in aerobic reuse water with low organic concentrations. The baseline current and sensitivity of the biosensor in response to formaldehyde were enhanced by 25% and 23% using microbial fuel cell effluent as the inoculum. The microbial community explained that the inoculum primarily influenced the performance of the biosensor by modulating species abundance, function and interactions. More importantly, the successfully commissioned biocathode sensor demonstrated rapid warning capability (Response time less than 1.3 h) for ECs such as fluoride, disinfection by-products and antibiotics in an actual landscape reuse system. Further, the sensor could quantify the concentration of a single known contaminant. Our study demonstrated a method for rapid early warning of ECs in an oxygen-rich, low-organics environment, promoting innovative development of monitoring technologies for water ecology and environmental safety.