Characterisation of reverse osmosis permeates from municipal recycled water systems using fluorescence spectroscopy: Implications for integrity monitoring

Reverse osmosis (RO) permeates from three Australian water recycling plants were characterised using three-dimensional excitation–emission matrix (EEM) fluorescence spectroscopy. The plants differed in terms of their RO operational configurations: RO feed water and pretreatment processes. Intermediate permeates from multiple staged RO treatment processes could be distinguished using Peak C (λEx/Em= 340/426 nm) and Peak T1 (λEx/Em= 285/350 nm) fluorescence. Monte-Carlo analysis of Peak C and Peak T1 rejection showed typical rejection of over 98% and permeate fluorescence intensities were used to determine Peak C as the most suitable for RO monitoring purposes. The results of this work indicate that fluorescence monitoring is a promising technique for sensitive quantitative and qualitative performance monitoring of RO treatment processes.