I’m in the market for a water filter and have narrowed down my selection to a couple of high-end activated carbon models that purport to remove chlorine, sediment, odor, asbestos (whatever), VOCs, and assorted chemicals from my water. (Not sure if the hydrogen remains, but that’s another matter.)
These filters are so effective they achieve 90-98 percent reductions in most everything.
Question is: do they also remove the fluoride? And is the fluoride I receive from brushing my teeth twice daily enough for decay prevention? (I am an adult.)
Not too long ago, my dad was shopping around for some storage/manufacturing space. A couple ten thousand square feet… nothing big but not something he could find in the local commercial/industrial parks.
One great deal he came across was a million+ sq foot facility that the parent company had just finished but was abandoning due to a need to relocate their operations. What was their operation? IC manufacturing. They’d chosen the location because the local water supply was unfluoridated and naturally low in F. Nuts to them, the council decided to start adding F, and it was cheaper to abandon the facility and rebuild elsewhere than to buy the filters necessary to remove the F.
Granted they needed absurdly superduper pure water. The last 0.1% is more expensive to remove than the first 99%, regardless of the impurity.
You might want to look into a seperate fluoride removing ion exchanger to put in series after the water filter. A quick look at froogle reveals a variety of filters that do claim to remove F (and they’re all two step at least, imagine that), for about $150-250. A quick look at regular water filters puts them in a range of $50-$75. So probably about 4 times more expensive than the filters you’re looking at now.
According to this site, activated carbon filters do not remove fluoride. You need an activated alumina filter. Or a steam distillation or reverse osmosis unit… those work, too.
Despite my mother’s admonition of never answering a question with a question, I must inquire what you are trying to remove?
Hardness (calcium and magnesium), iron, taste and odor compounds (e.g., H2S), etc.
While I await your response I must warn you that any filter, including GAC or its cousin Powdered activated carbon - PAC), must be cleaned or replaced to remain effective. Improperly used filters can become breeding grounds for bacteria.
Sorry - I should have combined these responses into one but I didn’t read ahead.
I do not mean to dispute you, however, the economics of what you describe don’t make sense. The cost of reverse osmosis (absent data on daily volume of treated water required, etc) would most likely be in the $0.75 to $2.50/1000 gallon range for a life cycle cost representing both capital and operating costs over a 10 year period. The capital cost alone for putting up the building must have been at least $$5-$10/square foot. Since IC facilities require high purity water they would have required some type of water treatment facility with or without the fluoride. As I said the cost of abandoning versus treatment don’t quite jive. I wonder if the issue may have been some underlying political (or other) issues?
I wouldn’t be surprised if the facts got mangled by my third or fourth hand account, but it makes sense to me.
I will say this, look at the costs and capacities of activated alumina filters compared to activated carbon filters of the same size. Finding out you’re going to be burning through more expensive filters at a much higher rate than you originally projected might just be a deal breaker.
Also could be the projected profits from leasing out the space were greater than the projected losses from dealing with the fluoride.
The dosage rate for fluoride addition to drinking water is nominally to achieve a final concentration of approximately 1 mg/l (or ppm) and in fact naturally occuring fluroide levels normally significantly above this would require treatment, in public water supplies, for removal of fluoride. Also, not to belabor the point, but the requirements for ultrapure (read deionized by either distillation, ion exchange, reverse osmosis, etc.) water are not going to made or broken by the minor contribution of 1 mg/l of a constituent. Most natural fresh water sources contain at least several hundred parts per million of dissolved solids.
Yes, but don’t mind me–I just started this thread
Let me rephrase. I’m not interested in removing fluoride. I want to keep it. I’m concerned that running drinking water through a three-filter system will also remove the healthful nutrients and fluoride, as well.
I don’t know how much calcium and other healtful minerals we get from drinking water. Does anyone know?
Drinking waters vary considerably in hardness, and the relative contribution of the two major cations that contribute to hardness (Mg and Ca) can vary also. But as a very general figure, your moderately hard drinking water might have around 40mg of Ca per liter. If the nutritional information from the back of my CVS vitamins is correct, that would mean that a liter of drinking water provides 4% of your daily 1g Ca requirement. That assumes the Ca is completely assimilable, of course. Even if you had a source of water with 100mg/l Ca, you’re still talking only 10% of your daily calcium in one liter.
That said, I agree with Waterman’s first post: We need to know what specifically you are trying to remove from your water and why before making any further recommendations.
Water impurities include the following general types:
a. Dissolved (and primarily ionized) such as calcium, chloride, etc.
b. Suspended inorganic matter
c. Soluble and insoluble organic constituents (may or may not be all VOC’s)
d. Microorganisms including bacteria and giardia, etc.
Most treatment methodologies are designed to focus on one type of removal for which they are the most cost effective solution. Granulated activated carbon (GAC or its sister powdered activated carbon - PAC) is most often used for trace removals of item c above. While it can remove “a” it is by no means the most efficient or cost effective way to achieve removal of dissolved inorganic constituents. GAC is not an effective means for removing item “b” and its efficacy for removing “d” is limited.
According to my vitamin bottle, the DV of iron is only 18 mg and I had thought that drinking water might be a significant source of iron in the diet, but according to this page
And since it seems like high levels of iron can lead to problems with staining and taste, I guess you’d be better off without the iron as long as you eat your green leafy vegetables.
Carnac, if you’re worried about lack of minerals in your filtered water, why not just add them back in once you’ve filtered it? That’s what some saltwater aquarists do when they prepare the water they use in their fish tanks. First they run the water through a very high-tech series of filters to remove essentially everything except H[SUB]2[/SUB]O, and then they add salt and other minerals back into the water in precisely the right quantities to keep their oh-so-expensive fish and corals happy. You could do something similar, right?
By the way, here’s a filter system similar to one I saw at a friend-of-a-friend’s house. He had a sediment filter, a carbon filter, a TFC reverse osmosis filter and finally a resin deionizer to suck up anything that might have snuck by the first three stages.
And what did he do with that water once he had gotten it to a level of purity not normally found outside of a chemistry lab? Dumped a bunch of salt into it…
Activated carbon filters do not effectively remove fluoride.
You might want to make sure that all that’s in your filters is activated carbon, though, if you’re concerned about it being removed.
Common treatment methodologies that “remove” dissolved constituents are distillation, evaporation, and reverse osmosis. These are capable of truly reducing the total dissolved solids (or mineral content) of natural waters. The first two methodologies are not “filters”. The latter is a membrane technology.
Softeners (ion exchange) exchange calcium and magnesium for sodium and hydrogen cycle ion exchange (rarely used in municipal water treatment) exchange calcium and magnesium for hydrogen. These systems do not reduce dissolved solids they just “exchange” constituents.
Filters, in the conventional sense, have been used to remove and reduce suspended solids from natural water bodies. Cloudy or turbid water requires filtration which is a separation of solid particles fom the water. Solids removal like this typically doesn’t impact dissolved solids.
Hydrogen sulfide (the smell of rotten eggs) is a gas that has a limited solubility in water is actually most effectively removed by chlorination and or air stripping. Total Organic Carbon (TOC) and other water soluble components of taste and odor problems are the constituents most commonly removed by use of Granualr or Powdered Activated Carbon.
The point of the above is that no one technology is truly effective in handling all categories of water contaminants. That is why it is so important to first identify what you want to remove and then develop a treatment methodology around that list.
FWIW, some communities have considered the use of GAC type of point-of-use filters that are discussed above and two reasons always emerge regarding their lack of support: 1) depending on individual users to properly operate and maintain the systems and 2) the cost to the users (not necessarily the community itself) would be higher.
Also, if you drink 2 liters of water a day containing 0.3 mg/l (which is the lower threshold for acceptance in public water supply) you will take in 0.6 mg/l of iron or about 3.3% of the 18 mg daily recommended intake.
