Your choice for a water purifier may be influenced by the quality of your water. Quality varies from place to place -- consider having yours tested to see what impurities it contains. The results of such a test could affect your choice of filter and help you decide whether you actually need one. Keep in mind that a thorough test can easily cost more than a hundred dollars. I notice that when I turn the tap on in some locations, it smells like a pool because the chlorine is so strong. However, there are many instances where I might not be able to smell the chlorine but there are other unwanted additions to my water.
Chlorine and lead are the two most common contaminants. Chlorine produces by-products that contribute to cancer and birth defects. The chemical itself may contribute to heart disease. Lead is toxic even in small amounts. High-level lead poisoning can cause organ damage and stunt the nervous system, leading to mental retardation. In many cities, public health officials are finding water contaminated with cryptosporidium, a microbe that can cause great harm to people with compromised immune systems.
Filters and Purifiers Before buying any type of water purifier, be sure to check out the different kinds available. Filtration systems can vary greatly in quality, efficiency, and price. The cost and trouble of keeping them maintained is an important consideration.
Here are five systems available for purifying. Not one of them is perfect -- each has distinct strengths and drawbacks. Always read the labeling on the product to see what it claims to filter. (Remember that ice should also be made from purified water -- not from the tap.)
Steam distillation is the surest method for a water purifier. The liquid is heated to boiling, and the steam is collected and cooled until it condenses again without the impurities. This method works, but distillers are expensive, slow, and use power. Distillation does not remove some volatile organic compounds, such as benzene and radon -- so the distilled water should go through a carbon filter before use.
Carbon filtration is probably the most popular water purifier system. Units containing specially prepared, porous carbon attach under the sink or at the tap. It works fast, removing chlorine, toxic organic molecules, and bad tastes from H2O. Look for specially designed, solid block and precoat-activated carbon filters, which also effectively reduce heavy metals such as lead and mercury. (Not all carbon filtration systems capture heavy metals or minerals). The downside to carbon filtration is it stops working as soon as the carbon becomes saturated with contaminants. Also, as the carbon collects organic matter, it starts to become a breeding place for bacteria. The bacteria shoot out into your first glass of the day -- unless you take a minute to flush the filter first.
Ion exchange rids dissolved minerals and toxic metals, but it is less efficient at removing organic molecules. Charged particles in the filter exchange themselves for charged particles in the H2O. These filters normally employ sodium in the exchange, so unless there's another process to remove it later, you could end up with harmful levels of sodium in the purified H2O. This method also corrodes pipes and can cause high levels of copper, iron, and lead in drinking water. Not a good choice.
Ultraviolet Light Purifiers use ultraviolet light to kill microorganisms and have no effect on chemical toxins.
Reverse Osmosis removes minerals and toxic heavy metals like lead, along with organic contaminants (including cryptosporidium). In an RO unit, the fluid is forced through an osmotic membrane (also called a semipermeable membrane, because the holes allow small H2O molecules, but not contaminant molecules, to pass through). Bacteria are blocked out, and they don't grow on the filter. All things considered, I think this is a good way to go. However, you should know that the process is slow and wastes a lot of water. RO water is very corrosive to pipes, so place the system near the tap.
Links(opens new window)
Presious Pearls provides hexagonally structured water.
FiltersFast offers a wide variety of filters.