An Introduction to Potable Water:
When we drink our usual glass of water every day, rarely do we give much thought to the process of producing it. Many of us may not realize there are different types of water we consume regularly and that these differences impact our taste experience or preferences, and most importantly, how safe that water is to drink.
The most important concern for any kind of drinking water should be whether it is potable or safe to drink. From the source of our water up to the point of drinking, there can be several harmful microorganisms and chemicals that can contaminate that water.
Most Common Treated Water: Chlorinated Water
The most basic type of drinking water that fulfills the potability requirement is chlorinated water. Treating water with chlorine kills most microorganisms in a fairly inexpensive manner. This is why most of our tap water at home is chlorinated. However, while chlorination is effective in killing harmful microorganisms, it cannot remove any existing chemicals that may be present in the water. This fact is especially important when it comes to well water, where there is usually a lack of comprehensive water testing. There can be different chemical contaminants that may have leached into the water.
Since chlorination is commonly applied at the water distribution source, there needs to be sufficient residual chlorine to ensure that water is free from microbial contamination up to the point of use. The Philippine National Standards for Drinking Water of 2017 requires water distribution companies to maintain a residual chlorine level of 0.5-1.5 mg/L. A consequence of this requirement is that the residual chlorine also gives off the typical “swimming pool smell and taste” to the water, thus impacting our drinking experience.
Alternative Treatments for Potable Water: UV, UF, and RO
A newer type of water treatment for potable water is through Ultraviolet Light. This technology is referred to by many names: UV Sterilization, UV Disinfection, UV Radiation, or simply UV Treatment. They all refer to the same technology. The way it works is that the UV light emitted by a lamp damages the replication ability of different microorganisms, effectively inactivating them. It is different from chlorination which damages the microbes’ physical structure directly, but both render the harmful microorganisms incapable of causing harm and disease to water when ingested.
The advantage UV treatment has over chlorine is that it does not impart any off-flavors to the water. The UV treatment can also be placed closest to the point of use of the drinking water in the treatment process, lessening the risk of contamination in between.
However, not all UV lamps are created equal. A certain wavelength, which is a measurement of the kind of UV light emitted, needs to be reached to effectively inactivate microorganisms. Apart from the wavelength, there should be sufficient intensity and contact time between the UV light and the water to be treated. These can be measured directly with a UV light monitor.
The most widely used water treatment in commercial and industrial settings for potable water is Reverse Osmosis or “RO”. This technology uses a membrane with very fine pores, averaging 0.0001 microns in size. It can remove not only microorganisms but also dissolved minerals from the water.
Unlike disinfectants, RO works by physically removing the unwanted contaminants from the water, instead of killing or inactivating them. As a reference, bacteria are generally 1-5 microns in size. By physically removing the contaminants, RO also has the advantage of not imparting any off-flavors and even has the added benefit of improving the taste of the water for sources with relatively high dissolved minerals.
At Numa, we have two models of water purifiers: UF and RO. The UF model uses an Ultra Filtration System, which filters out impurities up to 0.1 microns in size. This effectively removes up to 99.999% of bacteria just on size alone. But we wanted to increase the safety of our water even further, so we added a UV Sterilizer in case any bacteria or virus makes it through the UF filter.
The RO model uses the RO membrane to physically remove contaminants and impurities up to 0.0001 microns in size. Between the two, we recommend the UF for treating a municipal water supply, where the water has already been pre-treated for chemical contaminants that are small enough to bypass the UF filter.
We recommend the RO for areas with deep well water supply, or areas with high dissolved minerals in their water supply (i.e. >300 ppm in Total Dissolved Solids). When used correctly, you can be assured that the water from either system is extremely safe and will give you peace of mind with every glass.
Kommentare