title: Early non-destructive biofouling detection and spatial distribution: Application of oxygen sensing optodes.
abstract: Biofouling is a serious problem in reverse osmosis/nanofiltration (RO/NF) applications, reducing membrane performance. Early detection of biofouling plays an essential role in an adequate anti-biofouling strategy. Presently, fouling of membrane filtration systems is mainly determined by measuring changes in pressure drop, which is not exclusively linked to biofouling. Non-destructive imaging of oxygen concentrations (i) is specific for biological activity of biofilms and (ii) may enable earlier detection of biofilm accumulation than pressure drop. The objective of this study was to test whether transparent luminescent planar O2 optodes, in combination with a simple imaging system, can be used for early non-destructive biofouling detection. This biofouling detection is done by mapping the two-dimensional distribution of O2 concentrations and O2 decrease rates inside a membrane fouling simulator (MFS). Results show that at an early stage, biofouling development was detected by the oxygen sensing optodes while no significant increase in pressure drop was yet observed. Additionally, optodes could detect spatial heterogeneities in biofouling distribution at a micro scale. Biofilm development started mainly at the feed spacer crossings. The spatial and quantitative information on biological activity will lead to better understanding of the biofouling processes, contributing to the development of more effective biofouling control strategies.
authors.affiliation: Water Desalination and Reuse Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia. Electronic address: Nadia.farhat@kaust.edu.sa.
authors.forename: N M
authors.initials: NM
authors.lastname: Farhat
authors.affiliation: Water Desalination and Reuse Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
authors.forename: M
authors.initials: M
authors.lastname: Staal
authors.affiliation: Water Desalination and Reuse Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
authors.forename: A
authors.initials: A
authors.lastname: Siddiqui
authors.affiliation: Graz University of Technology, Institute of Analytical Chemistry and Food Chemistry, Stremayrgasse 9, 8010 Graz, Austria.
authors.forename: S M
authors.initials: SM
authors.lastname: Borisov
authors.affiliation: Water Desalination and Reuse Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
authors.forename: Sz S
authors.initials: SS
authors.lastname: Bucs
authors.affiliation: Water Desalination and Reuse Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; Delft University of Technology, Faculty of Applied Sciences, Department of Biotechnology, Julianalaan 67, 2628 BC Delft, The Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands.
authors.forename: J S
authors.initials: JS
authors.lastname: Vrouwenvelder
mesh_terms: D018407:Bacterial Physiological Phenomena; D018441:Biofilms / Q000254:growth & development*; D057219:Biofouling; D005374:Filtration; D010100:Oxygen / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification
chemical_list: D010100:Oxygen
keywords: Desalination; Early warning; Imaging; Sensor; Water treatment