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The Water Consumer’s Dilemma: From Filters to Distillers Part II

July 2nd, 2005

Treated Waters

Reverse Osmosis

Reverse osmosis is a method of treating water that utilizes a semi-permeable membrane to separate beneficial drinking water from less beneficial contaminants. Water is forced through the membrane, and the membrane blocks the passage of any contaminants that are physically larger than the water molecules. While this process is useful for treating water in which bacteria and heavy metals are the largest concerns, it is not ideal for purifying municipally treated water. In municipal water, most bacteria have already been killed or removed while chlorine has been added as a disinfectant. In the reverse osmosis process, contaminants like chlorine and volatile organic chemicals-whose physical size is smaller than that of water-pass through the membrane with the water. Economically speaking, reverse osmosis wastes about three gallons of water for every one gallon it purifies. While reverse osmosis is valuable for treating well water, it is certainly not the most economic or even safest drinking water choice.

Distillation

Water distillers boil water and capture the steam to remove any impurities from that water. The basic premise of the distillation system is that any contaminants with a lower boiling point than water will not become a part of the purified steam (which is later condensed into “pure” drinking water). While this process is useful for removing fluoride, bacteria, and heavy metals, it does not remove chlorine or volatile organic chemicals. These chemicals have a higher boiling point than water and travel safely with the purified steam into the condensation container. Distillation, also, is a wasteful process; approximately 75% of the starting water is discarded with the contaminants. Similarly to reverse osmosis, distillation is a useful process for treating well water, but it does not meet the economic or safety demands of a wise water consumer.

Filtration

Filtration has recently emerged as the most efficient and effective water treatment process. Using both physical and chemical filtration processes, a home water filter is capable of removing several of the most dangerous water contaminants, including chlorine. In physical filtration, water passes over the granular bed of a filter media that physically blocks the passage of contaminants. In chemical filtration, water passes over a specifically designed, ionic media that chemically attracts contaminants, encouraging them to break their bond with water molecules. Filtration wastes no water in its process. In addition, a point-of-use water filter can also remove lead that may have corroded into drinking water. For both economy and safety-if one is receiving municipally treated water-water filters provide the best drinking water product.

Entry Filed under: General Nutrition

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