IoT-Based Tryptophan-like Fluorescence Portable Device to Monitor the Indicators for Microbial Quality by E. coli and Biochemical Oxygen Demand (BOD5)

Tryptophan-like fluorescence (TLF) is a key indicator of water contamination, particularly of microbial origin and biodegradable organic compounds. This study introduces an Internet of Things (IoT)-enabled portable device (IoT-TLF-PD) for real-time monitoring of microbial quality and biochemical oxygen demand (BOD5). The device was tested using surface water (S1), secondary wastewater (S2), and final wastewater effluents (S3). Results showed significant correlations between TLF intensity, Escherichia coli (E. coli) counts, and BOD5, with R2 values of 0.77 (S1), 0.61 (S2), and 0.76 (S3) for BOD5, and 0.60 (S2) to 0.68 (S3) for E. coli. Considering various water samples, a strong correlation was found between E. coli and BOD5 with TLF intensity normalized by total organic carbon (TOC) concentration (TLF intensity/TOC). The R2 value for E. coli was 0.92, and for BOD5, it was 0.77. This indicates the necessity of accounting for organic matter concentration when interpreting TLF intensity in water quality assessments. The study confirmed the potential of the IoT-TLF-PD to serve as a cost-effective, real-time indicator for assessing water quality, especially for detecting microbial contamination. This technology offers a valuable tool for environmental monitoring and water management.