in a countercurrent direction to the water falling through packing material in the degasifier. The air effectively strips the unwanted gases from the water. Disinfection and stabilisation The permeate water from a NF separation is demineralised and may be disposed to large changes in pH, thus providing a substantial risk of corrosion in piping and other equipment components. To increase the stability of the water, chemical addition of alkaline solutions such as lime and caustic soda is employed. Furthermore, disinfectants such as chlorine or chloroamine are added to the permeate, as well as phosphate or fluoride corrosion inhibitors in some cases. Research trends Challenges in nanofiltration (NF) technology include minimising membrane fouling and reducing energy requirements. Thin film composite membranes (TFC), which consist of a number of extremely thin selective layers interfacially polymerized over a microporous substrate, have had commercial success in industrial membrane applications. Electrospunnanofibrous membrane layers (ENMs) enhances permeate flux. Energy-efficient alternatives to the commonly used spiral wound arrangement are hollow fibre membranes, which require less pre-treatment. Titanium Dioxide nanoparticles have been used to minimize for membrane fouling. See also References External links Project ETAP-ERN, that uses renewable energies for desalinization. Nano based methods to improve water quality - Hawk's Perch Technical Writing, LLC Nanotechnology Water treatment Filters Water desalination Membrane technology