Fluorescence analysis of centralized water supply systems: Indications for rapid cross-connection detection and water...

Better insight into non-potable reclaimed water and drinking water can produce more reliable risk assessment and help to achieve sustainable water reuse in the long-term. This study illustrates the effectiveness of fluorescence excitation-emission matrix (EEM) for rapid cross-connection detection. Based on samples collected from three different sites of China, it is identified that the overall fluorescence intensity was 6-31 times of reclaimed to drinking water in water samples at all FRI regions. This is shown to be highly sensitive over conventional water quality parameters. Furthermore, based on parallel factor analysis (PARAFAC), humic acid and tryptophan are considered as the main components contributing to fluorescence both in secondary and tertiary effluents. Total fluorescence intensities as well as fluorescence peaks of EEM pairs were investigated. Under different mixing scenarios, it is found that the signal is distinguishable as low as 20% of reclaimed water. This study also offers possibility of exploring portable devices with identified fluorescence peaks in EEM regions for risk prevention and water quality monitoring at end user sites.