Sustainable, Chemical-Free Drinking Water Production with Hollow-Fiber Nanofiltration at the Largest Dutch Utility

Hollow-fiber nanofiltration (HFNF) membranes with alternating polyelectrolyte nanolayer construction on polyethersulfone support are demonstrated as a sustainable alternative to spiral-wound NF/RO for treating eutrophic surface water. HFNF architecture enables inside-out crossflow operation with low fouling tendency, tolerance to hypochlorite exposure (up to 250,000 ppm-hours), and effective removal of organics, micropollutants, and pesticides without requiring extensive pretreatment. The chemical-free treatment scheme combines sand filtration pretreatment, HFNF, and GAC posttreatment to produce drinking water meeting safety standards while minimizing disinfection byproducts and emerging contaminants. HFNF’s selective rejection of divalent ions (MWCO range 400–800 Da) reduces concentrate monovalent ion accumulation compared to RO, simplifying discharge management and lowering total cost of ownership.