It is similar to the reverse osmosis method, but it is also a semi-permeable membrane, but it cannot control the removal of ions, because the pore diameter of the membrane is larger, between 10 and 200A.
Bacteria, viruses, pyrogen and particles can only be excluded, and water-soluble ions cannot be filtered.
The main function of the filtration method is to act as a pretreatment of reverse osmosis to prevent the reverse osmosis membrane from being contaminated by bacteria.
It can also be used in the final steps of water treatment to prevent upstream water from being contaminated by bacteria in the pipeline.
In general, it is used to judge whether the filter membrane is effective by means of the difference between water pressure and water pressure, which is similar to the activated carbon, which is usually used to remove impurities attached to it.
Distillation is ancient but also efficient water treatment method, it can remove any volatile impurities, but cannot be ruled out volatile pollutants, it takes a lot of water storage tank to store, the water storage tank and pipeline is the important cause of pollution, the blood dialysis water don't use this way to deal with.