Biochemical oxygen demand (BOD) serves as an important indicator in water quality monitoring. It provides valuable information for studying biology and conducting environmental impact assessments, making it the preferred method for environmental applications. Currently, the most common approach for BOD monitoring is the BOD5 standard detection method. However, this method has several drawbacks, like a long 5-day culture time, extended detection duration, complex operations, and low reproducibility of results. To address these issues, our study introduces a rapid BOD detection method, that focused on optimizing microbial immobilized particles and their detection capabilities. The method demonstrated better detection accuracy, stability, and reproducibility, with results available in less than 8 min. Our customization includes: •Prepared the particles using the cross-linking-embedding method by adding specific modifiers which are Polyvinyl Alcohol (PVA) and diatomite.•Improved the detection results, reducing the overall detection error by over 10%.•Confirmed our method' effectiveness in rapidly detecting BOD solution prepared in the lab, outsourced BOD standard solution and actual waste water samples with high accuracy.