AWWA MTC57636

A systematic investigation of the role of feed water recovery in combined (colloidal plus natural organic matter (NOM)) fouling of nanofiltration (NF) membranes is reported in this paper. A brief mathematical expression relating NF product water recovery to feed water concentration factors enables both qualitative and quantitative analyses of membrane fouling, which can be related to full-scale NF systems. Permeate disposal fouling experiments were carried out with a thin-film composite NF membrane and a bench-scale, crossflow membrane unit at various combinations of solution chemistries and hydrodynamic conditions. Results demonstrate that the effects of ionic strength, divalent ions (Ca2+), and initial flux on the fouling behavior are quite different in combined (colloids plus NOM) fouling compared to individual colloid and NOM fouling. Includes 8 references, figures.