Show simple item record

dc.contributor.authorSanawar, Huma
dc.contributor.authorPinel, I.
dc.contributor.authorFarhat, Nadia
dc.contributor.authorBucs, Szilard
dc.contributor.authorZlopasa, J.
dc.contributor.authorKruithof, J.C.
dc.contributor.authorWitkamp, Geert Jan
dc.contributor.authorvan Loosdrecht, Mark C.M.
dc.contributor.authorVrouwenvelder, Johannes S.
dc.identifier.citationSanawar H, Pinel I, Farhat NM, Bucs SS, Zlopasa J, et al. (2018) Enhanced biofilm solubilization by urea in reverse osmosis membrane systems. Water Research X. Available:
dc.description.abstractChemical cleaning is routinely performed in reverse osmosis (RO) plants for the regeneration of RO membranes that suffer from biofouling problems. The potential of urea as a chaotropic agent to enhance the solubilization of biofilm proteins has been reported briefly in the literature. In this paper the efficiency of urea cleaning for RO membrane systems has been compared to conventionally applied acid/alkali treatment. Preliminary assessment confirmed that urea did not damage the RO polyamide membranes and that the membrane cleaning efficiency increased with increasing concentrations of urea and temperature. Accelerated biofilm formation was carried out in membrane fouling simulators which were subsequently cleaned with (i) 0.01M sodium hydroxide (NaOH) and 0.1M hydrochloric acid (HCl) (typically applied in industry), (ii) urea (CO(NH2)2) and hydrochloric acid, or (iii) urea only (1340 g/Lwater). The pressure drop over the flow channel was used to evaluate the efficiency of the applied chemical cleanings. Biomass removal was evaluated by measuring chemical oxygen demand (COD), adenosine triphosphate (ATP), protein, and carbohydrate content from the membrane and spacer surfaces after cleaning. In addition to protein and carbohydrate quantification of the extracellular polymeric substances (EPS), fluorescence excitation−emission matrix (FEEM) spectroscopy was used to distinguish the difference in organic matter of the remaining biomass to assess biofilm solubilization efficacy of the different cleaning agents. Results indicated that two-stage CO(NH2)2/HCl cleaning was as effective as cleaning with NaOH/HCl in terms of restoring the feed channel pressure drop (>70% pressure drop decrease). One-stage cleaning with urea only was not as effective indicating the importance of the second-stage low pH acid cleaning in weakening the biofilm matrix. All three chemical cleaning protocols were equally effective in reducing the concentration of predominant EPS components protein and carbohydrate (>50% reduction in concentrations). However, urea-based cleaning strategies were more effective in solubilizing protein-like matter and tyrosine-containing proteins. Furthermore, ATP measurements showed that biomass inactivation was up to two-fold greater after treatment with urea-based chemical cleanings compared to the conventional acid/alkali treatment. The applicability of urea as an alternative, economical, eco-friendly and effective chemical cleaning agent for the control of biological fouling was successfully demonstrated.
dc.description.sponsorshipThe authors thank King Abdullah University of Science and Technology (KAUST) for funding this research project.
dc.publisherElsevier BV
dc.rightsUnder a Creative Commons license
dc.subjectReverse osmosis
dc.subjectmembrane fouling simulator
dc.subjectchemical cleaning
dc.titleEnhanced biofilm solubilization by urea in reverse osmosis membrane systems
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Division
dc.contributor.departmentEnvironmental Science and Engineering Program
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)
dc.identifier.journalWater Research X
dc.contributor.institutionDepartment of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
dc.contributor.institutionWetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, the Netherlands
kaust.personSanawar, Huma
kaust.personFarhat, Nadia
kaust.personBucs, Szilard
kaust.personWitkamp, Geert Jan
kaust.personVrouwenvelder, Johannes S.

Files in this item

Accepted Manuscript
JPEG image
Graphical abstract

This item appears in the following Collection(s)

Show simple item record

Under a Creative Commons license
Except where otherwise noted, this item's license is described as Under a Creative Commons license