Experimental study of filterability behavior of model extracellular polymeric substance solutions in dead-end membrane filtration

A series of model extracellular polymeric substance (EPS) solutions was prepared by using sodium alginate, humic acid and some proteins on the basis of the components of actual EPS extracted from sludge for laboratory-scale SBR by the formaldehyde–NaOH method. The dead-end model filter of these solutions was carried out with 0.1 μm PVDF MF membrane under a transmembrane pressure of 0.1 MPa and the filterability behaviors of these solutions were also investigated. The experimental results showed that the filterability behaviors of BSA, β-lactoglobulin and lysozyme model solutions with five times the protein concentration in the actual EPS were similar with that of the actual EPS solution; in addition, the addition of sodium alginate and humic acid enhanced the rejection of proteins, and the values of αc of model solutions increased with the addition of sodium alginate or humic acid, and especially the values of αc of the model solution greatly increased with the addition of humic acid, and the presence of protein in the mixed components model solutions caused the decrease of the αc values of sodium alginate.