Bod measurement system with flowthrough electrode.

Biochemical oxygen demand (BOD) is one of the most important and widely used parameters in measurement of organic pollution. BOD determination by the conventional method requires five days and is too protracted and complicated for use in process control. We constructed a microbial sensor for BOD estimation consisting of immobilized yeast cells (Hansenula anomala) and an oxygen electrode. The electrode was carefully designed and a flowthrough measuring system constructed. A biosensor response time of less than 15 minutes was achieved. A linear relationship was observed between decrease in current and sample solution (GGA, model waste water) BOD over the range 1-45 mg/l. The biosensor service life exceeded one year, with a relative standard deviation of less than 6% of BOD at a concentration of 20 mg/l.