Analysis of the Advantages and Disadvantages of Ro Reverse Osmosis Pure Water System

RO (Reverse Osmosis) water purifiers originated from American aerospace technology and were introduced to my country in the 1990s. Reverse osmosis is a membrane separation technology that uses a reverse osmosis membrane under pressure to separate the solvent and solute in a solution. Reverse osmosis applies pressure greater than the natural osmotic pressure to saline water (such as raw water), causing water to permeate from the side of higher concentration to the side of lower concentration, separating water molecules from other substances in the raw water. Because the micropores on the reverse osmosis membrane are extremely small, with a porosity of only 0.0001 μm, which is a few thousandths the size of bacteria and viruses, the water produced using this technology is pure water, containing no minerals or trace elements. Even urine filtered through it can be consumed directly. The rate at which water passes through the reverse osmosis membrane is extremely slow, so the water processing capacity is relatively small (4 tons of raw water = 1 ton of drinking water + 3 tons of wastewater).

The advantages of pure water are that it is free of bacteria and viruses, clean and hygienic, soft water, has a good taste, and is composed of small molecular clusters, making it easily absorbed by the human body. To demonstrate the purity of their water, some vendors have used electrolysis pens to test its conductivity, finding it to be ≤20 mΩ. Because it contains no minerals, pure water remains clear and transparent, while tap water or mineral water will show various colored precipitates, creating a stark contrast and misleading consumers, thus becoming a major selling point for water purifiers.

However, long-term consumption of large amounts of pure water, due to the concentration difference, can remove existing minerals from the body, causing calcium and trace element loss, thereby lowering immunity and increasing susceptibility to illness. Therefore, pure water is also called "nutrient-free water" and is known in the West as "bone-scraping water." The Shanghai Municipal Education Commission explicitly banned primary and secondary school students from drinking pure water as early as 1997.