Design and development of real-time bioelectrochemical sensor for wastewater monitoring with integrated alarm notification

Abstract

Bioelectrochemical sensors are a class of biosensors that use microbial metabolism to convert chemical signals from an analyte into a measurable electrical signal. Currently, conventional wastewater monitoring methods rely on chemical analysis, which are time consuming, costly, and typically performed off-site. Hence, bioelectrochemical sensors are a perfect candidate to address this issue due to their ability to provide rapid feedback on the presence of pollutants through electricity production. In this work, a two-electrode microbial electrochemical sensor (MESe) with modified anodes (carbon powder-coated, flame oxidised, acid bleached) were developed and tested against multiple pollutants. MESe with carbon powder-coated anode achieved the highest accuracy (R2) in the pollutant test ranging from 0.5891 to 0.9754 when correlated with chemical oxygen demand (COD) data. However, MESe often encountered signal issues due to blockages between the anode and cathode. To address this, a tubular-type MFCSe with modified air-cathodes (0.5 – 2.0 mg cm-2 PtC loading rate) was proposed to improve the MESe design, which demonstrated higher accuracy even without external power supply. MFCSe with 1.5 mg cm-2 PtC obtained the highest accuracy ranging from 0.8248 to 0.9655 when correlated with COD data. Cloud platform with alarm notification system was established to allow real-time online monitoring and two mathematical models (anomaly detection and change point detection) were integrated with the notification system to allow unmanned supervision. The MFCSe, along with its alarm notification system, was successfully deployed at an actual municipal wastewater treatment facility. This comprehensive system demonstrated its capability to detect and send an alarm for various operational scenarios, including fresh and diluted influent, mechanical disturbances, and surrounding noises.