Osmotically-induced Cleaning of Fouled Reverse Osmosis Membranes in Desalination
Author(s)
Labban, Omar
Goon, Grace Swee See
Foo, Zi Hao
Zhao, Xuanhe
Lienhard, John H
Date Issued
October 2019
Publisher
International Desalination Association
Citation
Labban, Omar et al. "Osmotically-induced Cleaning of Fouled Reverse Osmosis Membranes in Desalination." The International Desalination Association World Congress on Desalination and Water Reuse 2019, October 2019, Dubai, UAE.
Version
Author's final manuscript
Abstract
To counteract the effects of fouling, desalination plant operators ultimately resort to chemical cleaning, which
incurs system downtime, risk of membrane damage, and the generation of chemical waste. Driven by these
limitations, chemical-free cleaning has emerged as a potential alternative. Recent works have demonstrated the
viability of osmotically-induced cleaning (OIC), where a membrane effectively undergoes osmotic backwashing.
In light of conflicting reports, however, a deeper analysis and understanding of the underlying mechanisms
involved is necessary. In this work, the effectiveness of OIC is examined, underlying mechanisms are elucidated,
and potential applicability in the presence of spacers is investigated. Sodium alginate is adopted as a model
organic foulant and commercial RO membranes are operated to emulate fouling conditions in practice. Video
footage is presented to document the cleaning procedure and refine our understanding, while important
observations are noted. Experimental results demonstrate effective cleaning, demonstrating a flux recovery of 10-
30% depending on experimental conditions, while membrane integrity is preserved. To investigate the effect of
OIC on biofilms, a real biofilm of Cobetia marina is exposed to solutions of higher salinity. The results indicate
that while exposure to higher salinities does impact the biofilm spread and bacterial count, the method is far from
completely eliminating the biofilm or preventing its regrowth once operation is resumed.
Keywords: Reverse osmosis; Membrane fouling; Chemical-free cleaning; Osmotically-induced foulant
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
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Creative Commons Attribution-Noncommercial-Share Alike
Persistent DSpace Link
DOI of Published Version
https://wc.idadesal.org/wp-content/uploads/2019/10/IDA-WC19-Tuesday-2.pdf
