Water is one of the main needs and a source of life. This can be seen from the ratio of land and sea on earth where 71% is the ocean (Arifin, 2019), and the water content in the human body is more than 70% (Muhammad Syahid, 2019). With its abundant availability; however, not all water can be directly consumed by humans. For example, with high salinity, sea water cannot be directly consumed. Water does not only come from earth but it can also come from the rain. Based on this, the content or substances dissolved in water actually vary depending on where the source is.
Water quality can be examined based on the content or substances dissolved in it, either organic or pollutant substances that make water unfit for human consumption. The quality of polluted or unfitted drinking water for consumption can cause imperfect cell metabolism and disease for those who consume it.
Due to the problem and the main need for water, many water treatment systems have been created, including: Disinfectant (boiled, Chlorinated, Ozonized, Ultra Violet Light), Distillation, Microfiltration, and Filtering (Activated Alumina, Activated Carbon, Anion & Cation Exchange). In general, Reverse Osmosis (RO) is widely used in technology.
What is RO water? RO water is produced or treated water using a filtration technique with a very low filtration rate of 0.001 micron where the size of bacteria is 0.2 to 1 micron, and viruses are between 0.02 to 0.4 micron. By using the RO technique, it is expected to get the best quality water that can be consumed by humans.
At the beginning of its development, RO was used to desalinate seawater and remove almost all contaminants from the water to be treated.
RO effectively removes health-related contaminants such as arsenic, asbestos, atrazine (herbicide/pesticide), fluoride, lead, mercury, nitrate, radium, and others.
RO is carried out by applying high pressure to water and flowing it through a semi-permeable membrane until ion separation occurs. With the separation of ions, the water molecules form a barrier that allows other water molecules to pass through and block the movement of most contaminants. The rate of rejection of these contaminants varies from 85% to 95%, depending on the initial water quality before treatment.
From the various drinking water purification technologies above, it can be concluded that many effective technologies and methods are to remove some contaminants, but no single technology can remove all pollutants.