A BOD Sensor Using Immobilized Microbial Consortium in Alginate-Based Matrix for Rapid Detection of River Water Pollution

The development of a rapid sensor for Biochemical Oxygen Demand (BOD) is important for rapid determination of the degree of pollution in river water. A short-term BOD (BODst) has been developed using a consortium of locally isolated bacteria as the sensing element. YSI 52 Dissolved Oxygen Meter has been used to measure the oxygen uptake in the test solutions. Of the three alginate-based matrices, namely calcium alginate, calcium alginate-gluteraldehyde and polyvinyl alcohol-sodium alginate (PVA-SA), calcium alginate-gluteraldehyde was found to be the best microbial immobilization method. Typical response time of the developed BODst sensor was 8 minutes, and the immobilized microorganisms were suitable for single use. BOD response was observed at 37°C and pH7.0. For river waters, the BOD values estimated by the BODst biosensor correlated well with those determined by conventional BOD5 test using artificial wastewater (AWW) as the calibration solution.