Shedding light on water quality: prospect for real-time control Available to Purchase

Fluorescence spectroscopy has been used to measure gross water quality parameters and organic contaminants in a variety of water samples (surface, drinking and wastewater). Water samples exhibit characteristic fluorescence signatures and excitation and emission spectral data can be used to provide intensity data and “optical fluorescence fingerprints”. Sewage wastes exhibit broad band fluorescence centred at 350 nm and two relatively less intense bands at about 390 and 430 nm. Samples that have been treated in an aerobic digester show a substantial reduction in fluorescence around 350 nm. Normalised intensities in this region demonstrate good correlation with BOD, COD and TOC values (R² values between 0.85 and 0.91). Drinking and surface waters also demonstrate unique fluorescence characteristics, which provide individual characteristic fingerprints. Results are presented that demonstrate the usefulness of fluorescence spectroscopy for the qualitative and quantitative detection of certain organic species present in different water types. Tryptophan is quantified in drinking and surface waters at levels around 8 × 10^-9 mol l^-1. Optical fluorescence fingerprints are unique for particular water types and are readily altered in the presence of organic contaminants including phenol and pyrene. The possibility of using fluorescence techniques for the continuous noninvasive monitoring of water quality is discussed.