What Is The Best Technology For A Water Purifier?
We drink water through out the day, use it in tea and coffee, cook with it and wash our fruit and vegetables with it yet we rarely stop to consider what is in it. Of course periodically we can smell the unmistakable smell of chlorine so we know there is something other than pure water coming out of the tap. But, what else is in it?
A recent newspaper article reported that drinking water quality in one Australian state had 200 incidents where the water failed the state's water quality tests. The "incidents" included the failure of disinfection equipment at water plants, the presence of metals such as aluminium and lead, the presence of blue-green algae, and foul tasting water. While these may be exceptional circumstances, having a water purifier installed at home means you never have to worry about them.
What sort of water purifier should we use?
While there are many, many different types of household water purifier on the market they tend to fall into one or more of the following categories: Granular Activated Carbon (GAC) and carbon block, Ultraviolet radiation, Distillation and Reverse Osmosis. In some cases a combination of these methods may be used, for example, GAC and UV.
Granular Activated Carbon and Carbon Block
Most GAC devices are water filters rather than water purifiers. They remove odours and some aesthetic contaminants. The degree to which they remove bacteria, chemicals such as pesticides, depends on their construction and the age of the filter cartridge. Filters that are near the end of their useful life can allow contaminants to pass through. Further they can also allow bacteria to breed in the filter cartridge especially if the filter is not used for a period of time. Thus the water coming out can be more microbilogically contaminated than the water going in. If you are using one of the many forms of carbon filters it is important to change the filter cartridge at the recommended intervals to minimise the possibility of water contamination.
While ultraviolet (UV) radiation can destroy (or, more accurately, inactivate) bacteria it has little effect on other contaminants. Its effectiveness in destroying bacteria depends on the turbidity of the water and the length of time the water is exposed to the UV radiation. For this reason it is generally used after the water has undergone other filtration methods (such as Carbon Block). It requires a power source for the UV light.
Distillation is a relatively energy-intensive method. It involves heating the water until it vaporises and then condensing the water on a cool surface and collecting the runoff. It is not guaranteed to remove all contaminants as those with similar boiling points to water will also vaporise and condense with the water. Further the boiling process can cause minute droplets of unvaporised water to be carried with the steam. It also tends not to remove odours.
Reverse Osmosis water purifiers have one distinctive advantage - they can desalinate water. The downside to this ability is that when filtering drinking water they also remove all beneficial minerals. There ability to remove bacteria is dependent on the quality and condition of the semi-permeable membrane. While they remove many chemicals they are often not effective against the organic contaminants commonly found in drinking water. Further, they produce anywhere from 3 to 10 litres of waste water for every litre of filtered water.
Is there any alternative?
Yes there is. A number of international airlines provide purified water to their passengers using the proprietary "Structured Matrix" technology developed by General Ecology, Inc. The "Structured Matrix" uses three mechanisms to instantly purify water: Ultrafine microstraining, Broad spectrum molecular capture, and Electrostatic removal. All of these purification mechanisms work together to remove viruses, disease bacteria and other contaminants far smaller than submicron microfiltration alone can remove. In fact, the purification technology has been independently certified to meet US EPA standards for the removal of bacteria, cysts and viruses from drinking water without requiring the use of chemicals or electricity, and without requiring a waiting time or producing waste water.
More information and a comparison of the effectiveness of contaminant removal for each of these filtration/purification methods can be found at CrystalClearWater.com.au