Fouling of reverse osmosis membrane by organic substances in advanced wastewater reclamation

Bovine serum albumin(BSA) and sodium alginate were used to represent protein and polysaccharides.Orthogonal test with function of interaction was used to analyze the effects and their synergistic actions.Furthermore,scanning electron micrograph(SEM) was used to detect the organic fouling layer on membranes.The result shows that the impact of alginate on membrane fouling is more significant than that of BSA,and the synergistic influence between them can increase membrane fouling notably.Membrane fouling is more severe in the presence of Ca2+ compared to Mg2+ because of its ability to bridge organic substances,which can result in denser fouling layer.Increasing the ionic strength can lead to weaker electrostatic repulsion and rapid fouling.The images of membrane fouling surface illustrate that the gel of organic matter is thick and dense,which induces severe membrane fouling.