Cross-Flow Membrane Filtration is a method of removing the majority of dissolved salts, organics, viruses, bacteria and pathogens from water. Various membranes types include: Micro Filtration (MF) 0.01-1.0 Microns Ultra Filtration (UF) 0.005-0.1 Microns Nano Filtration (NF) 0.001-0.01 Microns Reverse Osmosis (RO) 0.0001 Microns (rating are approx. : 1 micron = 0.001 mm) MF and RO are the mostly commonly used Types, sometimes together in series. Because of the very small particles and Ions being removed, a Membrane system can only “filter” part of the total flow; some of the water must be used to flush the contaminants to waste otherwise the Membrane will be quickly fouled.