Water is the essence of life on earth. It makes up to 75% of the human brain and 75% of the trees. About 97% of the world’s water is either salty or undrinkable, 2% is frozen in ice caps and glaciers, and only 1% is available for humans.
But, due to its solvent nature, this 1% water also becomes contaminated and leads to many health problems. Dirt, germs, and chemical solvents are the major pollutants which make water polluted and render it unfit for human consumption. Hence, the need for a good water purifying system that can treat water and make it suitable for drinking.
There are three water purifying mechanisms – RO, UV and UF available in the market today. Let’s explore them, understand how they are different from one another and find out which is the best option to provide safe and pure drinking water.
Types of Water Filters
If the only problem with your water is grit, dirt, sediment, rust, or other such particles, a screening filter may be sufficient. Made of fiber, fabric, ceramic, or another screening medium, these simply catch particles—including, in some cases, small organisms like cysts and some bacteria. But don’t rely on them to handle disease-causing organisms, VOCs, metals, or the like.
Carbon Water Filters
If your water tastes, smells, or looks bad, a filter containing activated carbon (AC) may solve the problem. If you want to remove chlorine, pesticides, herbicides, radon, trihalomethanes (THMs), and some inorganic chemicals, carbon may do the trick.
Some, but not all, carbon filters are effective at reducing lead content. Solid-block and pre-coat absorption filters trap lead. Check the certification of the unit you’re interested in buying and, if claims are made regarding lead removal, ask for proof.
You can’t rely on a conventional carbon filter to remove salts, nitrates, nitrites, and some metals. And you shouldn’t rely exclusively on one to remove organisms. In fact, be aware that a carbon filter will accumulate the contaminants removed from water, and bacteria may even breed in it, so you must replace filter cartridges religiously, according to the manufacturer’s recommendations.
A carbon filter that contains pesticide silver may be registered—but, remember, is not endorsed—by the EPA. Studies show that these are not fully effective at eliminating bacterial growth or microbiological contaminants. Again, be sure any such claims are substantiated.
Effectiveness of a particular carbon unit is a factor of the amount of activated carbon it contains. You can buy whole-house, under-counter, countertop, and faucet-mounted styles, but the $30 faucet-end models are only marginally effective. Known as point-of-entry (POE) systems, whole-house units are recommended where a contaminant such as radon poses a threat to the entire household.
Reverse Osmosis Water Filters
If you must remove inorganic chemicals such as salts, metals (including lead), minerals, nitrates, asbestos, and some organic chemicals, consider a reverse-osmosis (RO) water filter.
Actually, most models include carbon pre-filters and post-filters, which will catch sediment, pesticides, herbicides, THMs, and radon. RO filters remove lead, but some don’t remove chlorine (if this is claimed, request proof of performance). The carbon post-filter is used to improve the water’s taste. Pre- and post-filter cartridges should be replaced annually.
Most RO filters are connected directly to plumbing and are located beneath the sink. A small tank stores clean water until needed, and tainted water drains out through a line connected to the sink trap. Drinking water flows through a special, separate sink-top spout. Some models have an automatic valve that eliminates the waste typically associated with RO filters—conventional models waste about 3 gallons for every gallon of water they produce. They generally cost from $200 to $400.
If you just want a portable, sink-top appliance that will rid water of most dissolved solids, such as salts, asbestos fibers, metals, minerals, particles, and some organic chemicals, an inexpensive water distiller may be just the thing. Distillers heat water until it turns to steam and then condenses the steam back into water in a separate chamber, leaving behind anything that won’t travel in the steam.
Unless coupled with a carbon filter, they will not remove all chemical pollutants and all bacteria. Most have to be filled manually, they use a considerable amount of electricity to operate, and they may take several hours to produce 1 gallon of water. Prices range from about $80 to $400—most popular models are about $200.
UV Water Purifiers
Ultraviolet (UV) disinfection water filters, which typically cost $150 or more, may kill bacteria and viruses, and clear the taste and odor of water, but they are not effective against chemical pollutants and may not work against cysts and spores. UV may be combined with carbon filters to kill bacteria; these units tend to cost from $300 to $700.
Pointers to help you select the best purifier
1. Water Quality: Asses the quality of water and accordingly choose a filter which can purify it the best.
2. Electric/ Non-electric: If the place you live in has erratic power supply then you may consider an RO purifier or a UV with storage.
3. Storage: Not all purifiers have storage option. If you wish to collect purified water or your locality has power supply issues, you should opt for a storage type. The capacity of the storage tank may be an important factor too.
4. Purification technique: Each purification method has its limitations in eliminating all the impurities present in the water. Different purifiers use different methods of purification. Depending upon the type of water, impurities and contaminants the purification method has to be chosen accordingly. Modern purifiers use two or more purification technique to ensure better quality of water.
5. Stages of purification: No single technique of purification works good so water is purified in stages. Each stage uses a different purification technique. More the number of stages more cleaner the water.
6. Quality of purification: Purified water should be potable, odor free and free from all hazardous elements.
7. Ease of Operation: The operation should be simple and easy. It is not worth a struggle for just a glass of water
8. Quality of material used: The material should be food grade, non-toxic, rust proof and durable. Aluminum reacts with salts and minerals and poses health hazardous. ABS plastics are testified.
9. TDS: Water has some elements essential for our body. During purification process these are also eliminated completely at times. Some purifiers have TDS management where the essential minerals and salts are retained. TDS control adds the minerals at the last stage of purification.
10. Capacity: It’s the quantity of pure water the filter can purify in an Hour(L/hr).
11. Maximum duty cycle: Maximum water that can be purified in a day.
12. Purification capacity(life of the filter): is the total quantity of water it can purify. A filter change is recommended after that.
13. Wall mounting: You can choose from over the counter or wall mounting. Some purifiers have both the option.
14. Aesthetics: Some models have very sleek design. You can choose one matching your kitchen décor.
15. Annual Maintenance Contract(AMC): The filters need replacement after their life or time period. Its better if you opt for the AMC.
Auto shut off : Once the storage tank is filled up, the auto cut off valve cuts off the water inflow into the RO purifier.
Purity indicators: shows the purity of input and output water.
Voice Alerts: Alert for UV fail and filter change etc. If not changed then the purifier does not function ensuring the safety of your family.
Auto-Flushing System: The filter membrane is flushed and cleaned automatically. This enhances the life of the filter.
Hot & Cold Water: advanced purifiers come with this options with the program on touch panel.