Fluorescence monitoring for cross-connection detection in water reuse systems: Australian case studies

摘要

A rapid, highly sensitive method for detection of cross-connections between recycled andnpotable water in dual reticulation systems is required. The aim of this research was to determinenthe potential of fluorescence spectroscopy as a monitoring tool at three Australian dualndistribution (drinking and recycled water) systems. Weekly grab samples of recycled and potablenwater were obtained over 12 weeks at each site and analysed for fluorescence excitation-nemission matrix (EEM) spectroscopy, UV254, dissolved organic carbon (DOC), electricalnconductivity and pH. Fluorescence EEM spectroscopy was able to differentiate between recyclednand potable water at each site by monitoring the protein-like fluorescence at peak T—annexcitation-emission wavelength pair of lex/em ¼ 300/350 nm. While electrical conductivity wasnalso able to distinguish between recycled and potable water, the differentiation was greatestnwhen using fluorescence. For example, the peak T fluorescence in recycled water was up ton10 times that of potable water in comparison with electrical conductivity that had a maximumn5 times differentiation. Furthermore, by comparing the protein-like fluorescence at peak T andnhumic-like fluorescence at peak A (lex/em ¼ 235/426 nm), the three different recycled waternsystems were able to be differentiated. Overall, fluorescence shows promise as a monitoring toolnfor detecting cross-connections.