Realizing BOD detection of real wastewater by considering the bioelectrochemical degradability of organic pollutants in a bioelectrochemical system

Biochemical oxygen demand (BOD) is an important water quality indicator that needs in-time detection to evaluate organic pollution degrees of wastewaters and improve wastewater treatment process parameters. However, present BOD detections were time-consuming (over 5 d) or only able to be applied in component-fixed wastewater. In this study, bioelectrogenic coefficient (k) was first proposed to characterize the bioelectrochemical degradability of organic pollutants and used for realizing the BOD detection of wastewater with different organic pollutants. The electrochemical biosensor (EBS) was established based on the bioanode and linear voltammetry sweep. The EBS could directly detect BOD within 2.1 min for the BOD range of 4-160 mg L-1 with possible expansion of detectable range by sample dilution, enabling stable detections over 90 tests with relative standard deviations < 6.1%. Through the k-based and temperature-based correction, the EBS successfully detected BOD in artificial wastewater and four types of real wastewater with relative errors < 5.4% and < 14.6%, respectively. This new strategy could develop biosensors to realize quick, accurate and continuous BOD detection in real wastewater.