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

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.

Automated summary

This study cultivated a biofilm reactor in situ for rapid determination of biochemical oxygen demand in seawater, without the need for phosphate buffer solution to avoid secondary pollution. Optimal effects of temperature and flow rate were observed, showing a wide linear range and high detection sensitivity under the optimal conditions.