Effect of extracellular polymeric substances (EPS) on membrane fouling: A case study of full-scale treatment plant

Severe and rapid fouling occurred in the ultrafiltration–reverse osmosis (UF–RO) system of an automotive company's treatment plant using water from Sapanca Lake, Turkey. Despite membrane replacement and additional pre-treatment, blockage reappeared within seconds of operation. To identify the cause, effluents from each treatment unit and 0.45 µm cartridge filters were analyzed using TOC, SDI, SEM, FTIR, and SMP–EPS analyses. Results revealed that carbohydrate-based extracellular polymeric substances (EPS) with gel-like structures and particle sizes exceeding 0.45 µm were the primary foulants. The investigated fouling event, which coincided with the spring season, was likely intensified by the increased microbial EPS release characteristic of algal blooms. Regular EPS monitoring is recommended to prevent similar fouling events in biologically active water sources.