Determination of seawater biochemical oxygen demand based on in situ cultured biofilm reactor

Abstract

Biofilm reactor was in situ cultured with seawater can be used for in situ BOD monitoring. • Biofilm reactor (BFR) was in situ cultured with seawater. • The BFR can be used for in situ detection of BOD in high salinity seawater. • The prepared BFR has high sensitivity and low detection limit. • The prepared BFR exhibits non selective degradation of different organics. • The secondary pollution to the environment can be avoided. In this study, a biofilm reactor (BFR) was in situ cultured for rapid determination of biochemical oxygen demand (BOD) in seawater. The microorganism in situ cultured with seawater can tolerate the high salt concentration, which enhances the BFR survivability and stability under the extreme conditions. No phosphate buffer solution is needed to maintain the system and the secondary pollution can be avoided. The effects of temperature and flow rate on BFR were optimized. In addition, the prepared BFR exhibits undifferentiated biodegradable ability for a wide range of organic substrates. Under the optimal conditions, it displays a wide linear range of 1.0–8.0 mgL -1 BOD with a correlation coefficient of 0.9776. The detection limit was 0.3 mg/L at the signal to noise ratio of 3. The 16S-rRNA gene sequencing technology was used to analyze the microbial species in BFR and Huangmao seawater. The results showed that the BFR can meet the requirements of rapid BOD determination for seawater.