Biochemical oxygen demand measurement by mediator method in flow system

Area of Science:

• Environmental Science
• Analytical Chemistry
• Biotechnology

Background:

• Mediator-based biochemical oxygen demand (BOD) measurement (BODMed) emerged recently.
• No flow system for BODMed has been previously reported, limiting its application.
• Conventional BOD5 methods are time-consuming and may require sample dilution.

Purpose of the Study:

• To develop and characterize the first flow system for mediator-based BOD measurement (BOD(Med)-FS).
• To evaluate the analytical performance and stability of the developed BOD(Med)-FS.
• To compare the accuracy of BOD(Med)-FS with the conventional BOD5 method using real wastewater samples.

Main Methods:

• Development of a flow system utilizing potassium ferricyanide as the mediator and carbon fiber felt for microbial immobilization.
• Determination of BOD values for glucose-glutamic acid (GGA) standard solutions.
• Analysis of real samples from a local wastewater treatment plant (WWTP).

Main Results:

• The BOD(Med)-FS can determine BOD values within 30 minutes.
• It exhibits a wide analytical linear range (2–200 mg L⁻¹) for GGA standards without dilution.
• The system demonstrates long-term operational stability (up to 2 months) and comparable accuracy to the conventional BOD5 method.

Conclusions:

• The developed BOD(Med)-FS represents a significant advancement in rapid and stable BOD measurement.
• This method offers improved efficiency and a broader analytical range compared to existing BODMed techniques.
• BOD(Med)-FS shows potential for reliable on-site monitoring of wastewater quality.