Occurrence and behaviors of fluorescence EEM-PARAFAC components in drinking water and wastewater treatment systems and their applications: a review

Abstract

Fluorescence excitation emission matrices-parallel factor analysis (EEM-PARAFAC) is a powerful tool for characterizing dissolved organic matter (DOM), and it is applied in a rapidly growing number of studies on drinking water and wastewater treatments. This paper presents an overview of recent findings about the occurrence and behavior of PARAFAC components in drinking water and wastewater treatments, as well as their feasibility for assessing the treatment performance and water quality including disinfection by-product formation potentials (DBPs FPs). A variety of humic-like, protein-like, and unique (e.g., pyrene-like) fluorescent components have been identified, providing valuable insights into the chemical composition of DOM and the effects of various treatment processes in engineered systems. Coagulation/flocculation-clarification preferentially removes humic-like components, and additional treatments such as biological activated carbon filtration, anion exchange, and UV irradiation can further remove DOM from drinking water. In contrast, biological treatments are more effective for protein-like components in wastewater treatments. PARAFAC components have been proven to be valuable as surrogates for conventional water quality parameter, to track the changes of organic matter quantity and quality in drinking water and wastewater treatments. They are also feasible for assessing formations of trihalomethanes and other DBPs and evaluating treatment system performance. Further studies of EEM-PARAFAC for assessing the effects of the raw water quality and variable treatment conditions on the removal of DOM, and the formation potentials of various emerging DBPs, are essential for optimizing the treatment processes to ensure treated water quality.

Characteristics of NOM Released to Water from Different Forest and Agricultural Soils

“…In coincidence with previous studies [8][9][10]20], two apparent peaks, reported to reflect humic acids (P1) and fulvic acids (P2) with Ex/Em at 325/445 nm and 230/445 nm, were found in all of the soils, while the obvious peak (P3) that represents the protein-like substances with Ex/Em at 230/370 nm appeared only in soils BF-1 and BF-2 (broadleaf forest) and PF-2 (paddy field).…”

“…Regarding the composition of NOM, in addition to the index of specific ultraviolet absorbance (SUVA), which reflects the extent of aromaticity of the constituting components [1,2,6,7], fluorescence excitation-emission matrix (EEM) spectroscopy is increasingly used to generate information that cannot be achieved either by TOC, UV260 or SUVA [8][9][10]. In addition to these, the molecular weight (MW) distribution of NOM can provide valuable information for better understanding the polydisperse nature of NOM and the removal behavior of the constituting components during various physicochemical water treatment processes [2,11,12].…”

Fluorescence spectroscopy for wastewater monitoring: A review

“…It separates the contribution of different fluorophores without 140 additional assumptions about their excitation and emission spectra (Cohen et al 2014). A thorough 141 description of PARAFAC method and components in wastewater is given by Yang et al (2015b).…”

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“…It is composed of myriads of organic compounds which play pivotal ecological and biogeochemical roles in the environment (Wang et al, 2014;Findlay and Sinsabaugh, 2003;Hansell and Carlson, 2002). Fluorescence excitation-emission matrix (EEFM) combined with parallel factor analysis (EEFM-PARAFAC) has become a popular tool for probing the fate of DOM and understanding its environmental behaviors in natural and engineered systems (Borisover et al, 2009;Ishii and Boyer, 2012;Stedmon et al, 2003;Yang et al, 2015).…”