Water Purification 101
If your water comes from a private source, such as a ground well or flowing spring, there are some important facts you should know.
- v People drawing water from private wells are responsible for assuring that the water is safe for consumption.
- v The U.S. Environmental Protection Agency only requires that municipal water sources be tested for about 80 of the 75,000 known contaminants.
- v The standards for safe drinking water are established for a 175-pound healthy adult and may not be satisfactory for children, women who are pregnant or nursing, or adults with compromised immune systems.
There are many methods that can be used to purify water and each one is best for removing a certain type of impurity or contaminant but may not be effective at all for others. Some of the more common water purification technologies are:
- v Distilliation - Water is heated to boiling and then cooled to condense the water vapor. Impurities are filtered out by the evaporation
- o Effective for: bacteria, lead, nitrate, sodium chloride, organic chemicals and pesticides
- o Pros: removes a wide range of contaminants, reusable
- o Cons: slow, requires a large amount of water and energy
- v Carbon Filtration - Water is passed through an activated carbon filter that absorbs odors, flavors, organic compounds and many hazardous chemicals
- o Effective for: hydrogen sulfide, radon, chlorine, volatile organic compounds, pesticides, benzene, colors and orders
- o Pros: removes objectionable odors and flavors
- o Cons: won’t remove heavy metals and the filter must be replaced periodically
- v Ion Exchange - water is percolated through a layer of resin beads that have a sodium exchange coating to “soften” water before using other treatment methods
- o Effective for: nitrates, sulfates, fluorides, iron, magnesium, calcium and manganese
- o Pros: removes dissolved minerals and metals effectively at a relatively low initial cost
- o Cons: doesn’t remove bacteria - in fact, beads can become breading ground for bacteria
- v Micro Filtration - water is passed through a porous filter to remove sediments and suspended materials
- o Effective for: sediments
- o Pros: removes all suspended impurities larger than filter pore size
- o Cons: doesn’t removed dissolved contaminants
- v Ultraviolet Radiation - low level ultraviolet light kills bacterial and viral pathogens but leaves no radioactive trace
- o Effective for: bacteria, viruses
- o Pros: sanitizes water
- o Cons: doesn’t remove suspended particles or ions
As you can see, no single purification method removes ALL the contaminants from water and you may have to employ several methods to make your water safe for drinking and cooking.
