Reverse osmosis water filtration involves the use of a semi-permeable membrane to screen out impurities. Originally developed as a means of separating salt from seawater, bottled-water companies now employ reverse osmosis filtration to safeguard their products from microorganisms and other pollutants. Home-based reverse osmosis filters also have grown in popularity in recent years. In addition, many hunters and backpackers purchase handheld reverse osmosis filtration units that enable them to safely use naturally occurring water sources during extended back-country trips.
Pathway to Purity
Most reverse osmosis water filtration units include a pre-filter that traps sediments, silt and other large particles. Pressurized water is then forced through the unit's cellophane-like membrane, which strains out impurities and contaminants as small as .001 microns in size. The water usually receives a final scrubbing in a carbon filter before it is ready to drink. The pre-filter, membrane and carbon should be changed periodically for the best results.
Benefits and Disadvantages
Reverse osmosis filtration effectively removes many potentially deleterious waterborne pathogens, as well as pesticides and pollutants such as chlorine, copper, nitrates, lead and arsenic. On the negative side, reverse osmosis water filtration is more costly and wasteful than other conventional treatment technologies. A home-based reverse osmosis filter may use several gallons of water to distill a single gallon of drinking water. Some naysayers also contend that reverse osmosis water filtration is actually too efficient because its removes minerals like magnesium and calcium that people need to stay healthy.
