Identification of fouling materials in the microfiltration of seawater laden with marine algae

In this study, fouling materials were identified in the microfiltration (MF) of seawater laden with marine algae. To this end, raw seawater spiked with either the dinoflagellate species without cell walls (Heterosigma akashiwo) or with cell walls (Prorocentrum micans) was filtered through a laboratory-scale MF system. Based on the results, polysaccharides, which were excreted by the marine algae, accumulated within the MF system and subsequently resulted in membrane fouling. Cell walls are closely related with polysaccharide excretion. The dinoflagellate species without cell walls released more polysaccharides than those with cell walls based on the unit surface area of the species. High-performance size exclusion chromatography analysis revealed that organic substances (1.1 and 22 kDa, molecular weight) were accumulated in the MF system. These organic substances could be the biofouling …