Water purification methods:
Several RO water system are commonly used in water purification. Their effectiveness depends on the type of contaminant supposed to remove and the type of application that purified water is assigned to.
• Filtration: Many types of filtration exist
o Common filtration: Also called particle filtration, it can use any filtering device, since a sand filter of 1 mm to a 1 micron.
o Micro filtration: Uses devices from 1 to 0.1 microns to filter bacteria and viruses.
o Ultra Filtration: Removes pyrogens, endotoxins, and fragments of DNA and RNA.
o Reverse osmosis: Often referred to by RO, reverse osmosis is the most refined liquid filtration level. Instead of a filter, this is to use a semi permeable membrane that allows only the solvent to pass through.
• Distillation: The oldest method of purification. It is cheap, but this it can’t be used for processes using water on demand. Water must be distilled and then stored for later use, making it again prone to contamination from improper storage.
• Adsorption on activated carbon: Operates as a magnet for chloride and organic components.
• Ultraviolet radiation: At a certain wavelength, this can cause infertility bacteria and the destruction of other microorganisms. There are two types of UV radiation.
o The first, so-called “254 nm” alter the nucleic acid (DNA) viruses, bacteria, parasites to prohibit reproduction, so they are considered inactivated.
o The second, so-called “254 and 185 nm” allows, through a radical reaction using oxygen dissolved in water, to oxidize the oxidizable organic matter, which will be removed by the ion exchange resins.
The difference between the two types of UV is the type of quartz that allows the wave 185 nm to pass through or not.
• Deionization: Also known as ion exchange, it is used to produce purified water on demand; it requires passing water through the resin layers. The negatively charged resin removes positive ions, while the positively charged resin removes negative ions.