Fouling and scaling in reverse osmosis desalination plants: A critical review of membrane autopsies, feedwater quality guidelines and assessment methods
Marc Philibert, Loreen O. Villacorte, Yuli Ekowati, Almotasembellah Abushaban, Sergio G. Salinas-Rodríguez
Abstract
Reverse osmosis (RO) desalination currently plays a vital role in addressing the critical and growing issue of water scarcity through desalination of brackish waters (BWRO) and seawater (SWRO). To ensure sustainable operation and longer membrane lifetime in an RO system, it is crucial to monitor and evaluate the feedwater quality of the desalination process. This article highlights the operational challenges faced by seawater and brackish water RO desalination plants through a review of full-scale plant membrane autopsies. The operational issues of particulate, colloidal, inorganic, organic, and biological fouling thus highlighted require to be managed and monitored for plants to perform efficiently. The paper then explores the potential and limitations of conventional and novel analytical methods such as modified fouling index (MFI), transparent exopolymer particles (TEP), liquid chromatography-organic carbon detection (LC-OCD), etc. as tools for the understanding and control of these issues. The application of these tools is then studied through a review of available RO feedwater quality which, compared to supplier and literature guidelines, allows to underscore the difficulties of matching these guidelines and finding proper control targets and measures for organic, biological, oxidative and inorganic fouling. Finally, the paper discusses an overview of areas of improvement on which to focus future research. • Reverse osmosis (RO) is increasingly applied to address water scarcity, but feedwater quality is crucial. • Operational issues observed in RO plants are discussed through a review of membrane autopsy literature. • Current and emerging RO feedwater assessment methods and guidelines are critically reviewed. • Supplier and proposed threshold guidelines of fouling/scaling potentials are discussed. • Comparison of guidelines with full-scale plant feedwater qualities highlight current limitations.