If the only problem with your water is grit, dirt, sediment, rust, or other such particles, a physical filter may be sufficient. Made of fiber, fabric, ceramic or other screening media, these simply catch particles--including, in some cases, small organisms like cysts and some bacteria. Don't rely upon them to handle disease-causing organisms, VOCs, metals or the like.
If your water tastes, smells, or looks bad, a filter containing activated carbon (AC) may solve the problem. If you want to remove chlorine, pesticides, herbicides, radon, trihalomethanes (THMs) and some inorganic chemicals, carbon may do the trick, too. Some --but not all-- carbon filters are effective at reducing lead content. Check the certification of the unit you're interested in buying and, if claims are made regarding lead removal, be sure they're substantiated. You can't rely upon a conventional carbon filter to remove salts, nitrates, nitrites, or some metals. And you shouldn't rely exclusively on one to remove organisms. In fact, be aware that a carbon filter will accumulate the contaminants removed from water and bacteria may even breed in it, so you must replace filter cartridges religiously, according to the manufacturer's recommendations. A carbon filter that contains pesticide silver may be registered--but is not endorsed--by the EPA. Studies show that these are not fully effective at eliminating bacterial growth or microbiological contaminants. Again, be sure any such claims are substantiated. Effectiveness of a particular carbon unit is a factor of the amount of activated carbon it contains. Although you can buy beneath-the-counter, countertop, and faucet-mounted styles, the $30 faucet-end models are only marginally effective. Whole-house systems are also available for $3000 or more. Such a system, known as point-of-entry (POE) is recommended for applications where a contaminant such as radon poses a threat to the entire house. If you must remove inorganic chemicals, such as salts, metals (including lead), minerals, nitrates, asbestos, and some organic chemicals, consider a reverse-osmosis (RO) filter. Actually, most models include carbon pre-filters and post-filters, too, which will catch sediment, pesticides, herbicides, THMs and radon. RO filters remove lead, but some don't remove chlorine (if this is claimed, request proof of performance). The carbon post-filter is used to improve the water's taste. Pre- and post-filter cartridges should be replaced yearly. Most RO filters are connected directly to plumbing, and are located beneath the sink. A small tank stores clean water until needed and tainted water drains out through a line connected to the sink trap. Drinking water flows through a special, separate sink-top spout. Some models have an automatic valve that eliminates the waste typically associated with RO filters--conventional models waste about 3 gallons for every gallon of pure water they produce. They generally cost upwards of $250. If you just want a portable, sink-top appliance that will rid water of most dissolved solids, such as salts, asbestos fibers, metals, minerals, particles, and some organic chemicals maybe an inexpensive distiller is right for you. Distillers heat water until it turns to steam then condense the steam back into water in a separate chamber, leaving behind anything that won't travel in the steam. Unless coupled with a carbon filter, they will not remove all chemical pollutants and all bacteria. Most have to be filled manually, they use considerable electricity to operate and they may take several hours to produce one gallon of water. Though prices range up to $1500, most are less than $400. Ultraviolet (UV) disinfection devices may kill bacteria and viruses, and clear the taste and odor of water, but they are not effective against chemical pollutants and may not work against cysts and spores. Ultraviolet is sometimes used in combination with carbon filters to kill bacteria. * Puratap Award-winning water purifier for clean, pure drinking tap water. www.puratap.com.au * Pure, Safe drinking water Katadyn-Steripen-Camelbak-Nalgene Hydration, Microfilters, Purifiers www.gear-up.com * Water Filter Systems Find Water Storage System Information & Resources Here! www.waterstoragesystem.net * Water Purifiers Hand made stoneware gravity fed water purifiers. Australian made. www.southerncrosspottery.com.au ********************************************************************** This message and its attachments may contain legally privileged or confidential information. If you are not the intended recipient, you must not disclose or use the information contained in it. If you have received this e-mail in error, please notify the sender immediately by return e-mail and delete the e-mail. Any content of this message and its attachments which does not relate to the official business of Eraring Energy must be taken not to have been sent or endorsed by Eraring Energy. No warranty is made that the e-mail or attachment(s) are free from computer virus or other defect. ********************************************************************** [Non-text portions of this message have been removed]
