A NOVEL BIOSENSOR BASED ON MICROBIAL ELECTROLYSIS CELL FOR RAPID ANALYSIS OF BIOCHEMICAL OXYGEN DEMAND

摘要

BOD measurement is often required for evaluation of water quality. Most used 5-day BOD measurement method is time consuming and requires skills. Although MFC based biosensors can measure BOD rapidly, they suffer oxygen leakage problem, damping the wide spread application. In this study, a novel biosensor for rapid determination of BOD was developed based on microbial electrolysis cell (MEC) technique, and its performance was evaluated. The biosensor utilized maximum current and coulomb yield as indicators of BOD level. For the best performance, system parameters were optimized as external applied voltage to be 0.7-0.9 volts, artificial BOD to be 10 to 100 mg/L when maximum current was measured and 10 to 400 mg/L when coulomb yield was measured. At the optimal conditions, the sensor responded to BOD linearly and was able to complete each measure in 10 min and 80-400 min respectively using maximum current and coulomb yield as BOD indicator. The repeatability of the system was high as indicated by relative standard deviation less than ±13%c for 6 measurements. For stability test, the system was stable over a period of 12 days as evaluated by relative standard deviation less than ±10.3%. These results demonstrated that MEC can be employed as a biosensor for on-line or off-line monitoring of BOD.