Exploratory analysis of excitation-emission matrix fluorescence spectra with self-organizing maps as a basis for determination of organic matter removal efficiency at water treatment works

Abstract

In the paper, the self-organizing map (SOM) was employed for the exploratory analysis of fluorescence excitation-emission data characterising organic matter removal efficiency at 16 water treatment works in the UK. Fluorescence spectroscopy was used to assess organic matter removal efficiency between raw and partially-treated (clarified) water to provide an indication of the potential for disinfection by-products (DBPs) formation. Fluorescence spectroscopy was utilized to evaluate quantitative and qualitative properties of organic matter removal. However, the substantial amount of fluorescence data generated impeded the interpretation process. Therefore a robust self-organizing map (SOM) technique was used to examine the fluorescence data and to reveal patterns in data distribution and correlations between organic matter properties and fluorescence variables. It was found that the SOM provided a good discrimination between water treatment sites on the base of spectral properties of organic matter. The distances between the units of the SOM map were indicative of the similarity of the fluorescence samples and thus demonstrated the relative changes in organic matter content between raw and clarified water. The higher efficiency of organic matter removal was demonstrated for the larger distances between raw and clarified samples on the map. It was also shown that organic matter removal was highly dependent on the raw water fluorescence properties, with higher efficiencies for higher emission wavelengths in visible and UV humic-like fluorescence centres.

Keywords

Fluorescence spectroscopy; Excitation-emission matrix; Organic matter removal; Self-organizing map; Drinking water treatment

Published in

Journal of Geophysical Research
2009, volume: 114, number: G4, article number: G00F07
Publisher: Wiley

SLU Authors

• Bieroza, Magdalena

  • University of Birmingham

UKÄ Subject classification

Environmental Sciences

Publication identifier

• DOI: https://doi.org/10.1029/2009JG000940

Permanent link to this page (URI)

https://res.slu.se/id/publ/78267