Biological organisms need to consume water to live. However, water is not only necessary for life, it is integral in many aspects of our day-to-day existence. Though it is present in nature and ultimately recycled through a variety of natural processes, water can be found in several impure states. Often these impurities are due to the presence of salts, mineral ions, bacteria, and micro-organisms. While these impurities can complicate water’s ultimate usefulness, scientists have conceived ways to counteract the impurities. Water can be purified through a number of means, but those means often address only specific needs. The most commonly found purification procedures are deionization, distillation, and reverse osmosis. Additional treatments are used to make potable or drinkable water. Let’s discuss about deionized water first.
Deionized water is a name for water that is free of non-essential salts. These non-essential salts include such things as copper, calcium, sodium, bromide, and other minerals. Scientists refer to these as mineral ions. The complicated process for extricating these mineral ions is known as deionization. It has many applications in different settings.
The presence of these mineral ions is not necessarily due to mankind’s industry. They can be a byproduct found in nature. Water collects in pools underground. Chemists have characterized water as one of the best universal solvents available. Although it operates at slow speeds, water will eventually dissolve many substances. Salts that are not bound in less soluble molecules can be found in water. This is a natural effect. For example, in areas like southern Texas, the earth is rich with calcium deposits. Therefore, San Antonio’s ground water supply is high in calcium.
The deionization process is a scientifically fascinating yet simple method. Exposing water to electrically charged resins evokes a chemical reaction. This reaction results in the unwanted mineral ions forming molecules with these resins. Filtering out the deposits leaves the water in a much purer state.
Though the deionization process effectively removes mineral ions, it does not actually have an effect upon bacteria or other micro-organisms, which may also be present.
Distilled Water (DI Water)
In addition to the deionizing process, water can be purified through a classic chemistry procedure known as distillation. The process uses evaporation and condensation techniques to remove salts as well as some biological impurities. Unlike the procedure for making deionized water, it can also prove to be more time intensive. Evaporation requires energy, and this can be achieved by manipulating temperatures and pressures. Distillation focuses on adjusting temperature to achieve this result.
Distilling water is done through the simple process of boiling water, capturing the steam, and then condensing the steam in a separate container. This process can be done in the home with no technology apart from a heating element a pair of containers, and a medium to transfer the solution from one container to another. For example, a pot of water, near an empty pot, with a glass serving dish acting as the capturing vessel is a sufficient setup to distill water. Of course, additional glassware can both refine and streamline this process.
When boiling the water, impurities are either killed or left in the ever-diminishing supply of water. Ultimately, the supply vessel will retain the salt crystals and impurities. The destination vessel will receive a purified version of the solution. While the process relies only upon basic processes from chemistry, it is not a perfect solution. Depending upon the amount of impurities, the distillation process may need to be repeated to obtain the purest possible solution unlike deionized water process.
Reverse Osmosis (RO)
Like distillation, reverse osmosis purifies water through the use of a procedure perfected by chemists. Instead of manipulating temperatures, reverse osmosis uses a pressure-based system to remove impurities and therefore deliver purified water.
This is made possible by the use of a semipermeable membrane. The normal osmosis procedure relies upon the idea that a high-pressure system will filter through a membrane to fill a lower pressure area. By adjusting the membrane’s pore size, it can allow small particles through and retain larger sized particles. Reverse osmosis, however, uses a slightly difference process. Instead of relying upon membrane pore size, it uses solute concentration, pressure, and the water flux rate to deliver a purified drinking water.
This option is terrific for handling larger mineral ions, such as the salts found in seawater. Unfortunately, reverse osmosis does not perform a mineral ion extraction process with the same efficiency as deionization. In fact, the deionized form of water will be purer in less time than that generated through reverse osmosis. However, reverse osmosis serves a clear function and is less resource intensive than deionization.
Ground water always requires some kind of treatment to fit the physical and chemical qualifications to be considered potable or drinkable. These treatments can be performed on two levels: The community scale and the home scale. In some instances, water is purified at both levels. Although the specifics vary between the United States, Europe, and other nations of the world, the end result of these treatments is the same: The treatments provide a system by which water can be made drinkable.
On the community scale, water is subject to numerous purification schemes at water treatment facilities. These are often aimed to keep infectious contaminants to a minimum, using good bacteria and chemical processes to both remove the bad bacteria and potentially harmful chemicals.
On the home scale, citizens take the responsibility to make their own water supplies potable. For those using wells, this can include steps and mechanical and chemical processes to remove impurities in the ground. For those using a citywide water supply, this scale of treatment can include smaller scale filters that remove unwanted impurities from the delivered water.
Keeping sanitary water supply conditions is paramount to maintaining a healthy community. Drinking water that is not purified after being used to carry human and animal waste, detergents, or other harmful chemicals can have enormous ramifications upon a populace. Unsurprisingly, impure drinking water has historically been tied to several large-scale pandemics.