Study of BOD microbial sensors for waste water treatment control

A microbial sensor consisting of immobilized yeast or bacterial cells and an oxygen electrode was developed for the estimation of biochemical oxygen demand (BOD). A flow-through system was used, and the response time was within 20 min. A linear relationship was observed between the relative current decrease and the BOD of the sample solution within the range of 1-45 mg/L. The storage lifetime was greater than 1 yr. The reproducibility was quite good, within 6% fsd at a concentration of 20 mg/L BOD. Satisfactory results were attained when the biosensor was applied to the determination of BOD in brewery-plant and glutamate-plant wastewater and in a river.