跳至主要内容

Carbon Drinking Water Filters

Carbon is one of the oldest technologies available for drinking water filtration.  Sanskrit texts from 2,000 B.C. speak about filtering water over charcoal and examples exist in Egyptian tombs as well.
Carbon was, and is, a pretty effective technology for filtering out turbidity, or unclear water, and will improve the taste and odor profile in water.  In fact, most modern membrane technology will use carbon as a pre-filter, post-filter, or both.

How Carbon Filters Work

What carbon does well is largely a property of its physical structure.  It is extremely porous.  One pound of carbon will have up to 100 acres of surface area.
How it actually works is through a process of adsorption where something is getting trapped in that extremely porous surface of the carbon.
In addition to the sediment, taste and odor use written about over 4,000 years ago, carbon is also effective at the reduction of a few other contaminants:

Volatile Organic Compounds (VOCs)

The EPA houses these nasty chemicals under a list of 32 compounds.  Many might be somewhat familiar and include benzene, carbon tetrachloride, dioxin, styrene, toluene, chloroform, and vinyl chloride.  One of the other 32 items is total trihalomethanes (TTHMs).  It’s the TTHMs list where things get weird, that “one thing” is actually contaminants numbering in the thousands of compounds and many are the byproducts of disinfection, primarily from the use of chlorine.

Chlorine

Carbon is actually great at removing chlorine.  However, the Chemical Manufacturers Association and it’s lobbyists have absolutely promised us that it is not a health hazard, merely an aesthetic preference.  Regardless, carbon is great at removing chlorine given a slow enough flow rate over the media bed.
In a related story, I probably should have someone else start my car for the next few weeks.  I’d probably be safer double-crossing a crime family than dare upset the Chemical Manufacturers Association or say anything about the countless amount of research on chlorine and cancer rates.

What Carbon Isn’t Good At

Carbon is virtually useless when it comes to the removal of dissolved compounds.  If you take the carbon gravel you’ll find in a pitcher-style filter or refrigerator filter, these aren’t going to significantly touch dissolved inorganic compounds or lead, copper, and mercury.
Similarly, these charcoal filters aren’t going to reduce the suspended salts or radionuclides.  Probably three of the biggest hot-button issues that are not addressed at all by carbon are nitrates, flouride, and sodium.

Pathogen Control

In the EPA’s microbiological control side of things, there are four characteristics:  turbidity (floating stuff), cysts (cryptosporidium & giardia), bacteria and viruses.  Carbon is pretty good on the first.
For the rest, carbon is not only ineffective, but possibly counterproductive.  That same porous property of carbon will catch some bacteria.  And it’s dark, damp and temperature controlled.  That’s also the recipe for growing some species of bacteria.  Using your basic carbon filter on water with pathogens or simply using that filter for too long can be far more dangerous than one would think.
That “reset” button on the front of the refrigerator is removing the warning light, not the problem.

Selecting a Carbon Filter

Carbon is really, really basic.  It is a matter of only a few characteristics.

Construction / Density

Cut open a Brita filter or your refrigerator filter.  Most of those are the same gravel you’ll use in a fish tank.  Water is extremely lazy.  Given the choice between fighting through your intermittent gravel or just going around it, that water is going to go straight into your glass.
You’ll find other higher quality filters that are extremely dense, filtering down to as small as 0.5 microns.  In general, high-density carbon blocks will outperform the gravels and many of the loose granulated activated carbon (GAC).

Flow Rate / Contact Time

Like all physical treatment, if water goes over the media bed too fast, virtually nothing is filtered.  You can’t take a small filter, tie it in before the water softener, and expect to have any results going through the system.  So the efficacy of an 18″ block carbon filter will be far, far greater than that of a 4″ long gravel Brita-style filter.

 “The Extras”

While carbon is not only ineffective, but counterproductive, in dealing with pathogens, some of the better filters will combine use silver for its bacteriostatic properties.  You can actually get to pretty decent filtration with some carbon filters.

Keys on Carbon Filters

Like any water technology, look for the certifications.  If they’re not presented front and center on the marketing material, there is probably a reason.  Most are merely taste and odor filters making your filter about 4,000 years old.
Probably the other big issue is the replacement life.  Some of these manufacturers will speak to 10,000 gallons of chlorine reduction capability, but if the VOC and TTHM life is diminishing at 1,000, when should you replace it?

评论

发表评论

此博客中的热门博文

HOW TO STERILIZE WATER DURING AN EMERGENCY Would you know how to sterilize water during an emergency? Although uncommon in Canada, hurricanes, floods and even water mains breaking can interrupt regular water service. Typically, in an emergency situation, the authorities recommend that you drink sterilized water, or bottled water, to avoid any disease-causing microorganisms and harmful pollutants that could be in your water. The following steps will help you sterilize water that you do have available. In the event of an emergency situation, use only sterilized water for drinking, cleaning, preparing meals, cooking, and brushing your teeth. Just a few drops of contaminated water is enough to make you sick. Methods to Sterilize Water: 1 ) Boiling:  If have power during the emergency situation, boiling your water is a good way to sterilize water. Let cloudy water settle. You can filter it through a coffee filter or paper towel to get rid of sediment. Bring the water to a...
发表评论
阅读全文

What Is Better For You- Bottled Water Or Tap Water?

Everyone knows that drinking an adequate amount of water is critical to our survival, but should we worry about whether we get our water from a bottle with a nice label or from the kitchen sink? According to Mr. Benjamin Grumbles, the head of the United States Environmental Protection Agency’s water programs says “It’s an urban myth that bottled water is safer than tap water .” Many consumers admit to actually drinking both tap water and bottled water. For most people, if you have a filter at home, you probably could not distinguish the taste between the two. Nearly half of bottled water comes from a tap not the artisan springs and beautiful tropical waterfalls as we would like to imagine. In those cases, the water is filtered in many of the same ways as a home water filter works, except on a much larger scale. Chlorine and other contaminants are removed from the water prior to bottling. If you are still trying to decide between the two, there is no question that tap water is bett...
发表评论
阅读全文

Is your water filter counterfeit?

Is it time to change your refrigerator’s water filter? Be careful about where you buy the replacement. Many consumers, perhaps attracted by lower prices, are being duped into purchasing counterfeit water filters. These convincing but fake filters, which can be nearly impossible to distinguish from the real thing, may put consumers’ health and property at risk. Only one of these filters is genuine. Can you tell the difference? AHAM and its refrigerator members Amana, Beko, Blomberg, Bosch, Electrolux, Frigidaire, Gaggenau, GE, Jenn-Air, KitchenAid, LG, Maytag, Miele, Samsung, Sub-Zero Wolf, Thermador and Whirlpool, along with testing and certification organization NSF International and the Water Quality Association, in the  Filter It Out  campaign to call awareness to the significant problem of counterfeit and deceptively labeled refrigerator water filters. The problem Counterfeit water filters are being sold online every day. But even though these products may ap...
发表评论
阅读全文