Direct capillary nanofiltration — a new high-grade purification concept Original Research Article

Capillary nanofiltration (NF) enables raw water to be treated in a single step to produce high quality permeate. The permeate can be used as process water for the industry. Trial studies show that a stable operation is achievable using capillary NF without pretreatment (in other words direct NF), that the technique saves energy, that there is a low use of chemicals and that the permeate is of a high quality. The capillary NF membrane module combines the favorable cleaning properties of capillary ultrafiltration membranes with the favorable separation properties of NF membranes in terms of the removal of bacteria, viruses, color, hardness and pesticides.