A PARAFAC-Based Long-Term Assessment of DOM in a Multi-Coagulant Drinking Water Treatment Scheme

Abstract

A parallel factor (PARAFAC) analysis approach was used to study the character and composition of dissolved organic matter (DOM) in a multicoagulant (two aluminum-based coagulants) full scale drinking water treatment plant. A three year, long-term assessment was conducted based on deconstruction of the excitation-emission matrices (EEM) of over 1000 water samples collected before and after parallel coagulation treatment basins. Two humic moieties and a protein-like group were identified in the raw and treated waters. Apportionment of fluorophores was established using a novel approach based on the overall fluorescence intensity (OFI) of PARAFAC components. Uncorrected matrix correlation (UMC) revealed minimal changes of the fluorescence moieties after treatment (UMC > 0.98), and a comparable effect of both coagulants on the structure (UMC > 0.99) and distribution of these groups. Coagulation increased the proportion of the protein-like fluorophore and preferentially removed a humic-like group irrespective of the coagulant. Preference for this moiety was supported by a coagulant-affinity factor derived from the association between PARAFAC components after treatment. The suitability of a PARAFAC-based approach for coagulant evaluation/selection was demonstrated when compared to a dissolved organic carbon (DOC)-based criterion. This paper contributes to the understanding of the behavior of PARAFAC components in water treatment processes and presents several approaches for the future monitoring and control of coagulation at full scale treatment facilities.

Long-Term Comparison of Disinfection By-Product Formation Potential in a Full Scale Treatment Plant Utilizing a Multi-Coagulant Drinking Water Treatment Scheme

“…Coagulation of the raw water sample has been found to have little effect on the signature of the fluorophores but rather, decreases the fluorophore intensity which correlates to a decrease in DOC of the water [47]. The two different coagulants in this study exhibited different preferential removal of DOC.…”

“…for Alum and ACH, respectively. Studies have shown that fluorescence components that correlate to THM formation are humic-like components C1 and C2, while HAA formation correlates with humic-like components and microbial-derived component (C3) [17,47]. PARAFAC component scores, which have been shown to correlate with THM formation, were 10%-20% higher in ACH treated water than water treated with Alum.…”

State of the Art of Online Monitoring and Control of the Coagulation Process

“…Here the organic substances are characterized by excitation-emission matrices that are analyzed by multi-way techniques, in particular parallel factor analysis (PARAFAC) [31,32]. By evaluating data from a full-scale drinking water treatment plant, Sanchez et al [33] have demonstrated that this approach was suitable to evaluate the performance of two coagulants. Shutova et al [10] identified a number of fluorescence parameters that were useful to characterize the properties of organic substances with respect to treatability.…”

Fate and fouling characteristics of fluorescent dissolved organic matter in ultrafiltration of terrestrial humic substances

“…EEM-PARAFAC is very useful in tracing different sources/compositions of DOM. For example, Sanchez et al (2014) reported using EEM-PARAFAC that humic-like substances were preferentially removed from a bulk DOM by aluminum-based coagulation processes. Meanwhile, it was reported that protein-like fluorescent components were more effectively eliminated by membrane filtration than humic-like components (Shutova et al, 2014).…”