A review of recent literature demonstrates
that by monitoring the fluorescence of dissolved organic matter (DOM), the ratios of
humic-like (Peak C) and protein-like (Peak T) fluorescence peaks can be used to identify
trace sewage contamination in river waters and estuaries, a situation analogous to
contamination detection in recycled water systems. Additionally, strong correlations have
been shown between Peak T and biochemical oxygen demand (BOD) in rivers, which is
indicative of water impacted by microbial activity and therefore of sewage impacted
systems. Hence, this review concludes that the sensitive detection of contamination events
in recycled water systems may be achieved by monitoring Peak T and/or Peak C fluorescence.
However, in such systems, effluent is treated to a high standard resulting in much
lower DOM concentrations and the impact of these advanced treatment processes on Peaks
T and C fluorescence is largely unknown and requires investigation. This review has
highlighted that further work is also required to determine (a) the stability and distinctiveness
of recycled water fluorescence in relation to the treatment processes utilised, (b)
the impact of matrix effects, particularly the impact of oxidation, (c) calibration issues for
online monitoring, and (d) the advanced data analytical techniques required, if any, to
improve detection of contamination events.