Molecular interference for surface sites as a hidden driver of coagulation impairment in wastewater-impacted drinking water production
File(s)
Supporting information
Accepted version
Author(s)
Liu, Mengjie
Zhu, Baofeng
Graham, Nigel JD
Yu, Wenzheng
Type
Journal Article
Abstract
The presence of effluent organic matter (EfOM) in drinking water sources, a consequence of unplanned potable reuse, challenges the efficacy of conventional coagulation processes. This study employs a multi-scale analytical approach to reveal that EfOM does not simply increase organic loading but triggers a molecular-level interference with natural organic matter (NOM) for active sites on floc surfaces, manifested as preferential adsorption of EfOM components. Through integrated application of FT-ICR-MS, X-ray photoelectron spectroscopy, floc characterization, and contact angle measurements, we demonstrate that EfOM components, particularly lipid- and protein-like molecules, exhibit preferential adsorption onto reactive surface hydroxyl groups on aluminum flocs, thereby inhibiting the removal of aromatic, high-molecular-weight NOM fractions. This competitive adsorption enriches floc surfaces with hydrophilic C–O and COOH groups, elevating electrostatic repulsion and impairing inter-floc bridging, ultimately yielding smaller, less-settleable flocs. As a result, finished water contains a more diverse organic portfolio. It shows significant enrichment in heteroatomic (N, S, P) species characterized by high unsaturation and a low oxidation state, which are molecular features that have been previously linked in the literature to enhanced disinfection byproduct formation potential. Our study elucidates the mechanistic pathways linking molecular interference to impaired treatment performance, and underscores the need to develop advanced treatment strategies to mitigate downstream water quality risks.
Date Issued
2026-10-15
Date Acceptance
2026-07-09
Citation
Water Research, 2026, 305
ISSN
0043-1354
Publisher
Elsevier BV
Journal / Book Title
Water Research
Volume
305
Copyright Statement
Copyright © 2026 Elsevier Ltd. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Publication Status
Published
Article Number
126477
Date Publish Online
2026-07-10