Water, basic cleansing, Filters vs Purifiers http://www.beprepared.com/Articles/filvpur1.html Water Filters vs Water Purifiers ---------------------------------------------------------------------- ---------- What is the difference between water filters and purifiers? Consider cooking noodles as a comparison. Colanders are the water filtration of noodle cooking. A colander performs a rather passive but effective action. It just sits there as water is poured through it, catching the noodles you want separated out from the water. Another way to separate what you want from your boiling pot of noodles is to stick some tongs in and hunt for the noodles. That's almost how water purifiers work. They have components that contain chemicals which actively kill viruses and bacteria rather than straining them out. Most manufactured water purifiers also have a filtration element built in so that there are multiple stages of water cleansing. So filters strain out particles as water is forced through the filter and purifiers chemically kill the particulates. Is that all there is to say on the subject? Not hardly. Is one system more effective than another? The fact is that they each outperform the other in certain ways. Which bacteria and viruses does each system catch? Will you get sick if you have one and not the other? These are questions you will need answered in order to competently find a water cleansing system to meet your needs. Particulates and Water Cleansing Protozoa: only filters can treat for protozoa. The largest microorganism are Protozoa: single-celled microscopic amoebas. They can be cleaned out of drinking water by filters but not by purifiers. They are approximately 2 microns in size. (The measurement of micron is frequently referred to in water filtration and purification. The micron measurement is exactly one millionth of a meter --- minuscule, but about the size of disease-causing microorganisms). Protozoa, specifically the Giardia parasite, can cause "Beaver's fever", or giardiasis, an intestinal diarrhea illness. One good thing about protozoa is its large size. This makes it easy to filter out. Many of the leading filters on the market filter particles as small as 0.2 microns, meaning that they will catch protozoa. Interestingly, protozoa are immune to chemical purification treatments because of their hard, protective shell. This is one reason that many purifier manufacturers choose to also have some sort of filter element on their purifiers. Bacteria: both filters and purifiers can treat for most bacteria. Bacteria are the next largest particulates in water that can cause illness. Salmonella and E. Coli are some examples of bacteria. They are approximately 0.2 microns and larger in size, meaning that filters will be able to catch them as long as the filter pores are at least as small as 0.2 microns. Purifiers can also kill bacteria. Without catching bacteria a person will be in danger of getting Cholera and Typhoid Fever. Viruses: only purifiers can eliminate viruses. The next smallest particulates in the water are viruses. This is where filters drop out of the race. Viruses are so small (0.004 microns) that filters can't reliably catch them (some experts say viruses that small always "ride" on a host particle which is large enough for filters to catch, in which case filters would be effective in treating for viruses). Some examples of viruses are Hepatitis A, Polio, and the Norwalk Virus. They can be killed by purification, chemical disinfecting, and boiling. If you plan to do a lot of international traveling where you need to treat water before drinking you should get a water purifier. Viruses are more common outside the United States. Other Considerations There are other things to consider that should be investigated at the time of purchase. One is cost, of course. Costs vary. The prices for both filters and purifiers span from dollars to hundreds of dollars. Another consideration, related to cost, is the amount of cleansing the filter/purifier can do before parts need to be replaced. You can only strain so many pots of noodles before your colander is crammed full of noodles. Similarly, filters clog and need to be replaced. If you have a filter that needs frequent replacement it could become very costly. Also, you may not have access to the replacement elements during an emergency so filters that need frequent replacement of parts will become ineffective quickly. Another negative aspect of filters is that sometimes you can filter faster than the filtering element can clean. Filters work by pumping a handle manually. Sometimes you have to pump very slowly to catch all the particulates in the water. Impatient, forceful pumping can shove particles through the filter and into your drinking water. Purifiers have equally significant downfalls. Because the active ingredient for treating water in a purifier is iodine, some people should not drink water from a purifier. It is recommended that pregnant women or people with thyroid problems do not drink from iodine-treated water. Also, iodine can add a foul taste. Other Alternatives Many people resort to boiling water that they draw from streams or lakes. This is a very effective method of killing microorganisms. Its drawbacks include the time it takes to boil water over a fire and the inconvenience of having a pot handy and fuel available. Iodine tablets are another method used to treat water. It is inexpensive, compact, and will kill most microorganisms. Unfortunately it is less effective against Giardia and ineffective against Cryptosporidium. Iodine also takes 20 minutes and adds a foul taste. Conclusion Water filters and purifiers are two totally different Products that use two different methods to clean water. Each has different strengths and weaknesses. This article gives you a starting point. More in-depth information is available from retail stores that have these Products. Also, many water purifier/filter manufacturers will send out test results upon request. Resource: www.purwater.com/html/protlvls.htm Home ---------------------------------------------------------------------- ---------- 1-800-999-1863 Copyright Monday, August 13, 2001 Emergency Essentials 362 S Commerce Loop, Orem, UT 84058. Please address all questions and comments to Webmaster@beprepared.com