This process has the advantage of retaining beneficial mineral salts in the water, experiencing little rejection. They are cleaned by recirculation in inverse direction. They work with pressures lower than those they operate in inverse osmosis. They improve the natural taste of water since they only remove impurities and keep water filtered within the standards of microbiological purification. For example, a membrane of extreme filtration in a battery of filters of 20 and 5 micron cartridges can be used at the outlet.
The extreme filtration cartridge is simply a fiber mallet hydrophilously bound to capillary membrane filters. These filtering capillaries have a very porous asymmetric structure in which the feeding water follows the way of great pores outside the wall whereas small pores are within the internal wall. This Ster-O-Tap system patented as a low pressure membrane has a membrane technology unique in its type for its high averages of flow with minimum operative pressure and a rigid control on the measurement of pores which makes it very effective for microbiological control.