Biofilm reactor based real-time analysis of biochemical oxygendemand

We reported a biofilm reactor (BFR) based analytical system for real-time biochemical oxygen demand (BOD) monitoring. It does not need a blank solution and other chemical reagents to operate. The initial dissolved oxygen (DO) in sample solution was measured as blank, while DO in the BFR effluent was measured as response. The DO difference obtained before and after the sample solution flowed through the BFR was regarded as an indicator of real-time BOD. The analytical performance of this reagent-free BFR system was equal to the previous BFR system operated using phosphate buffer saline (PBS) and high purity deionized water in reproducibility, accuracy and long-term stability. Besides, this method embraces many notable advantages, such as no secondary pollution. Additionally, the sample solutions are free from temperature controlling and air-saturation before injection. Significantly, this is a real-time BOD analysis method. This method was successfully carried out in a simulated emergency, and the obtained results agreed well with conventional BOD5. These advantages, coupled with simplicity in device, convenience in operation and minimal maintenance, make such a reagent-free BFR analytical system promising for practical BOD real-time warning.

► A biofilm reactor together with two oxygen probes was used for real-time analysis of biochemical oxygen demand.
► The system does not need blank solution to operate and requires no chemical reagent.
► This analytical method was validated to be free from washing.
► Organic residue was never a question in this method.
► The simplified procedures made it promising for real-time BOD warning/determination.