In situ microbial fuel cell-based biosensor for organic carbon

The biological oxygen demand (BOD) may be the most used test to assess the amount of pollutant organic matter in water; however, it is time and labor consuming, and is done ex-situ. A BOD biosensor based on the microbial fuel cell principle was tested for online and in situ monitoring of biodegradable organic content of domestic wastewater. A stable current density of 282 +/- 23 mA/m(2) was obtained with domestic wastewater containing a BOD5 of 317 +/- 15 mg O-2/L at 22 +/- 2 degrees C, 1.53 +/- 0.04 mS/cm and pH 6.9 +/- 0.1. The current density showed a linear relationship with BOD5 concentration ranging from 17 +/- 0.5 mg O-2/L to 78 +/- 7.6 mg O-2/L. The current generation from the BOD biosensor was dependent on the measurement conditions such as temperature, conductivity, and pH. Thus, a correction factor should be applied to measurements done under different environmental conditions from the ones used in the calibration. These results provide useful information for the development of a biosensor for real-time in situ monitoring of wastewater quality. (C) 2011 Elsevier B.V. All rights reserved.