Abstract

The measured response of rapid biochemical oxygen demand (BOD) biosensors is often not identical to those measured using the conventional 5-day BOD assay. This paper highlights the efficacy of using both glucose–glutamic acid (GGA) and Organisation for Economic Cooperation and Development (OECD) BOD standards as a rapid screen for microorganisms most likely to reliably predict real effluent BODs when used in rapid BOD devices. Using these two synthetic BOD standards, a microorganism was identified that produced comparable BOD response profiles for two assays, the MICREDOX® assay and the conventional 5-day BOD5 test. A factorial experimental design systematically evaluated the impact of four factors (microbial strain, growth media composition, media strength, and microbial growth phase) on the BOD response profiles using GGA and OECD synthetic standard substrates. An outlier was identified that showed an improved correlation between the MICREDOX® BOD (BODsens) and BOD5 assays for both the synthetic standards and for real wastewater samples. Microbial strain was the dominant factor influencing BODsens values, with Arthrobacter globiformis single cultures clearly demonstrating superior rapid BODsens response profiles for both synthetic and real waste samples. It was the only microorganism to approach the BOD5 response for the OECD substrate (171 mg O2 L−1), and also reported BOD values for real waste samples that were comparable to those produced by the BOD5 test, including discriminating between filtered and unfiltered samples.

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