Deciphering membrane biofouling induced by micro-/nano-plastics in nanofiltration: metagenomic insights and spacer-driven mitigations
File(s)
Accepted version
Supporting information
Author(s)
Liu, Xinhui
Yang, Yu
Graham, Nigel JD
Takizawa, Satoshi
Ng, How Yong
Type
Journal Article
Abstract
Nanofiltration (NF) is an effective process for micro-/nano-plastics (MNPs) interception, but the impact of accumulated MNPs on the microbial community structure and metabolic pathways of biofilms on NF membranes remains unclear. This provides uncertainty with respect to membrane biofouling behavior and the risks to efficient NF operations. In this study, the size-dependent (20 nm–25 μm) and concentration-dependent (0.1–50 mg·L−1) effects of MNPs on the biofouling of a NF membrane treating secondary wastewater effluent were studied. Three MNPs-tolerant, hypermetabolic and polystyrene-degradable genera (i.e., Acinetobacter, Novosphingobium and Asticcacaulis) were detected in biofilms as dominant taxonomic compositions. MNPs led to an increase of 19.3 %–76.7 % in biomass contents and a more rapid decrease in permeate flux, with 0.1 mg·L−1 of 80 nm NPs causing the most severe membrane biofouling. Metagenomic analysis revealed that MNPs upregulated enzymes involved in exopolysaccharide (ExoA/L/M/P/Q/X/Y/Z) and tyrosine (COMT, FeaB and AOC3) biosynthesis and quorum sensing (PhzF and CiaH/R), and suppressed cell motility pathways including flagellar assembly and bacterial chemotaxis. Novel types of perforated column spacer (PCS) enhanced the hydrodynamics of the membrane feed with a lower pressure drop and higher fluid velocity, introduced micro-jets and greater mass transfer inside feed channels, thus eliminating the deposition of MNPs and mitigating membrane biofouling. Overall, a greater understanding of the interaction mechanisms between MNPs and membrane biofouling in secondary effluent filtration will help develop more effective MNPs management strategies and achieve more sustainable NF operations.
Date Issued
2025-08-01
Date Acceptance
2025-04-18
Citation
Water Research, 2025, 281
ISSN
0043-1354
Publisher
Elsevier
Journal / Book Title
Water Research
Volume
281
Copyright Statement
Copyright © 2025 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies. 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
123682
Date Publish Online
2025-04-19