Fan Cheng Meng, Pieh Yu Chang, Yi Hsiang Su
ABSTRACT Graphical abstract showing that, after one year of operation at the Jibei desalination plant, traditional chemicals with 2.5–4.0 h soaking and alkaline followed by acid cleaning achieved the best CIP performance. This study evaluates clean-in-place strategies for restoring membrane performance in the seawater reverse osmosis system at the Jibei desalination plant after one year of operation. The variables include chemical types, soaking and circulation durations, traditional versus commercial products, and the acid/alkaline sequence. Performance was evaluated using normalized differential pressure, normalized water permeability, and normalized salt passage. The results indicate that acid cleaning or alkaline cleaning alone provides limited recovery. Extending circulation and soaking durations to 2.5 to 4 hours enhances cleaning effectiveness; however, excessive soaking time to 8 hours decreased water permeability and increased salt passage. However, salt passage may be influenced by the chemical sequence. Although commercial products demonstrate effective cleaning, their costs are substantially higher than traditional chemicals, making traditional chemical more cost-effective. In this study, the commercial-product cost approximately 2.7 times higher than the traditional-chemical. In addition, alkaline cleaning followed by acid cleaning increased water permeability by 4.4% and reduced salt passage, outperforming the reverse sequence. Overall, for reverse osmosis systems operating in Jibei marine environment, it is recommended to use traditional chemical agents, control soaking durations between 2.5 and 4 hours, and perform alkaline cleaning followed by acid cleaning to achieve optimal performance recovery.