The application of fluorescence spectroscopy to organic matter characterisation in drinking water treatment

Abstract

Key to effective disinfection byproduct (DBP) management is source water control and management, and more specifically, organic matter (OM) control and management. However, the content and character of OM in source waters is spatially and temporally variable, and the prediction of its composition is challenging. Water treatment companies require adequate analytical techniques for OM characterisation to maintain the operation of the water supply and treatment systems adjusted to constantly changing environmental conditions. There is a requirement, therefore, for an improved understanding of OM composition and character in source water, how that composition and character varies with flow conditions, and how this impacts on drinking water treatment. This paper demonstrates that fluorescence spectroscopy offers a potential alternative to other analytical methods of OM characterisation. The advantages of fluorescence include rapid, sensitive and selective characterisation of OM, no sample pre-treatment, small sample volume, and the potential for on-line monitoring incorporation. Fluorescence can provide useful information on OM reactivity and treatability together with an indication of the OM sources (allochthonous or autochthonous). The paper discusses a body of literature which has identified relationships between fluorescence spectra and OM physico-chemical properties (i.e. degree of hydrophobicity, microbial content), has applied fluorescence spectroscopy to characterise the changes in OM upon disinfection, and has related the fluorescence properties to DBP formation. Further work is required in the robust management of data arising from fluorescence spectroscopy analysis and, in particular, Excitation Emission Matrices. Consideration must be given as to how the data might best be employed to greatest effect on a routine basis at WTW.

Portable LED fluorescence instrumentation for the rapid assessment of potable water quality

“…TOC is often synonymous with natural organic matter (NOM) because organic contaminants in naturally sourced water supply systems generally represent an insignificant fraction of the TOC (Leenheer and Croué, 2003). More sophisticated analytical techniques which differentiate physico-chemical properties are also available, including: resin abstraction (used principally to determine hydrophobicity), high performance size exclusion chromatography (HPSEC), gas-chromatography-mass spectrometry (GC-MS) and UVvisible absorbance optical properties (Chin et al, 1994;Visco et al, 2005;Bridgeman et al, 2011). Such techniques are predominantly laboratory-based and labour intensive, requiring extensive sample preparation and analysis, rendering them impractical in studies involving many sampling sites or frequent monitoring.…”

Cross-connection detection in Australian dual reticulation systems by monitoring inherent fluorescent organic matter

“…An emerging alternative approach to monitoring, characterizing and tracking aquatic DOC is by way of a number of fluorescence-based techniques [64][65][66][67][68]. Fluorescence analysis of organic matter has been continually evolving over the last 20 years of water science research, and is currently showing great promise for detailed characterization of many different water sources.…”

“…In non-impacted river waters, DOM is predominantly derived from plant material, whereas sewage-derived DOM has been linked to having microbial origins [108]. The research applications of aquatic fluorescence tracking have also been extended to include drinking water sources [68]. Several fluorescence studies have recently been undertaken to investigate the performance of drinking water treatment processes and have been able to successfully detect membrane fouling events [109,110] as well as to quantify organic matter removal and efficiency [111][112][113][114].…”

Calibration, standardization, and quantitative analysis of multidimensional fluorescence (MDF) measurements on complex mixtures (IUPAC Technical Report)

“…The initial and final steps in the implementation of EEM/SFS-based analytical methods generally requires the use of chemometrics, first to assess the reproducibility and robustness of the measurement itself, and second to produce an output in terms of a qualitative result or quantitative value. The second aspect is outside the scope of this paper, but there are many reviews available describing the various applications in biotechnology, food science [71], and environmental analysis [72][73][74][75][76][77], for example. The application of chemometrics to the fluorescence data analysis used for calibration/standardization can generally be split into four distinct elements or steps: 1.…”