Algal-derived organic matter (AOM), particularly transparent exopolymer particles, has been suspected to facilitate biofilm development in membrane systems (e.g., seawater reverse osmosis). This study demonstrates the possible role of AOM on biofouling in membrane systems affected by marine algal blooms. The tendency of AOM from bloom-forming marine algae to adhere to membranes and its ability to enhance biofilm growth were measured using atomic force microscopy, flow cytometry, liquid chromatography and accelerated membrane biofouling experiments. Adhesion force measurements indicate that AOM tends to adhere to clean membranes and even more strongly to AOM-fouled membranes. Batch growth tests illustrate that the capacity of seawater to support bacterial growth can significantly increase with AOM concentration. Biofouling experiments with spiral wound and capillary membranes illustrate that when nutrients availability are not limited in the feed water, a high concentration of AOM – whether in suspension or attached to the membrane – can substantially accelerates biofouling. A significantly lower biofouling rate was observed on membranes exposed to feed water spiked only with AOM or easily biodegradable nutrients. The abovementioned findings indicate that AOM facilitates the onset of membrane biofouling primarily as a conditioning platform and to some extent as a nutrient source for biofilm-forming bacteria.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was financially supported by IHE Delft Institute for Water Education, Wetsus Centre of Excellence for Sustainable Water Technology and the Water Desalination and Reuse Center at KAUST. We acknowledge the analytical/technical support of Z. Nyambi, M. Gharaibeh E. Spruijt, E.I. Prest and S. Huber. We thank the two anonymous reviewers and L.H. Kim for their constructive feedback and the members of the Wetsus research theme “Biofouling” for fruitful discussions.