Purifier bottles

Joe Talmadge · Jun 17, 2004

Hi folks,

I did a search on this, but couldn't find any threads with current info.
I'm going somewhere where I'll be doing some hiking, and the water is suspect. Not sure what nasties are in it, but I'm pretty sure viruses are part of the problem.

I've been considering getting one of those water bottles filters, for carry on day hikes (this won't be the main water source). Something like this:

http://www.katadyn.ch/site/us/home/outdoor_products/our_products/ultrlight_series/exstream_bottle/

The last thread in here that I saw on these bottles, there was a complaint that the filters in these bottles were too coarse. But things have changed -- as you can see, the katadyn bottles not only claim to filter out all big nasties, but also claim to be bona fide purifiers that kill viruses as well. Do you believe them?

What I could do, to be doubly sure, is bring some of those Miox tablets with me, and drop them in the water. Supposedly, it kills viruses in 15 minutes, but takes up to 4 hours for the tough cysts. So, I use the Miox tablets to quickly kill the viruses, then use the water bottle to filter out the rest of the nasties.

Thanks,

Joe

alco141 · Jun 17, 2004

i tried one of the waterbottle/filter combo's once, did not like ti much, although it was not the one you are talking about.

alex

storyville · Jun 17, 2004

Hey Joe,

The Katadyn bottles function very reliably as filter and purifier, and they get rid of everything instantly: the filter catches the protozoa and bacteria, and the carbon element kills the viruses. Nothing gimmicky here, it is a proven system simply adapted to the shape of a water bottle. I'm not sure what "too coarse" means (pore size?), but it should do well for day hikes esp. if you have another main water source. The main concern is that they filter water very slowly (0.3 liters per minute maximum), so you can't count on them for filtering large volumes of water, i.e., for filling, say, a 100 oz/ 3 liter Camelbak style bladder. (It would take something like 30+ minutes.) So not good for very hot weather conditions. The secondary concern is that they tend to clog a bit faster than pump style filters. To extend its usable life, it's best to skim from the surface of a still water source connected to a moving water source (i.e., a pool adjacent to a stream or river). Not only do bigger particles (dirt, etc.) sink to the bottom, so do the most common cysts like giardia and even crypto as they are relatively "heavy" compared to (less common) bacteria.

By "Miox tablets" I assume you're referring to the Katadyn Micropurs? They are technically a chlorine dioxide treatment, which may be the same thing as mixed oxidation ("miox") but I believe MIOX is a trademark of the MIOX Corp. which makes a kick-ass but expensive purifier sold through MSR. In any case, using a Katadyn bottle and Micropur tablet is unnecessarily redundant, esp. since the bottle works instantly w/out the long time window. The Micropurs are a great, inexpensive back-up, though; and they would be better for treating larger volumes of water.

Incidentally, RE viruses: Don't know where you'll be hiking, but while viruses are a big concern in developing/ underdeveloped countries, they are still extremely rare in US/ Canadian water sources. The most common viral source is human feces. Water sources near urban areas obviously run a higher risk, but even there protos and bacteria are far more common. (Viruses have a short lifespan and do not reproduce in water.)

My 2¢
Glen

Sundsvall · Jun 17, 2004

storyville said:
Hey Joe,

(Viruses have a short lifespan and do not reproduce in water.)

My 2¢
Glen

Viruses are technically not alive until they find a host. They are freely floating RNA or DNA fragments, thus they are immortal.

Joe Talmadge · Jun 17, 2004

Thanks guys. It's indeed an underdeveloped country, and there are viruses in the water. I realize these bottles can't do huge volumes, it's a backup. And yes, I meant the Micropurs as backup to the purification bottle.

Does this purifier filter out chemicals, ala a charcoal filter? I don't understand whether "carbon element" refers to charcoal or something else.

Joe

storyville · Jun 18, 2004

Joe,

Yes, the charcoal in filters is an active carbon element. The Katadyn, and filters by other reputable makers, will easily screen metals (e.g., lead, copper, iron) just like home-use filters like a Brita drip system. But I don't know about the effectiveness of filters/ purifiers against things like pesticides or fertilizer; they should effectively filter out any solids but I don't know about chemical content. If you know what chemicals may be neutralized by charcoal, and/or how, please do share!

If at all possible, of course, it's best to collect water upstream of farmlands, factories, logging mills, etc. Locals may know about hazards in nearby water sources. Also, the Micropur pills will not, of course, screen out metals or other solids.

Sundsvall,

Viruses are not a concern until they have been cultivated in a host, yes? As for "immortality": Medical professionals I've spoken with (including my neighbor, a virologist in the Biology Dept. at UC Irvine) and commonly available text sources (e.g., CDC website, Lifespan.org, MadSci.org) all refer to the "lifespan" of viruses, where and how long they "live," how they can be "killed" (or better, avoided), etc. Do you believe this language is misleading?

Last note on viruses: Someone with more knowledge can chime in, but even in underdeveloped countries I believe viruses are vastly more likely to be transmitted by means other than water: e.g., not washing hands before eating (Hepatitis A), unprotected sex (Hepatitis A, HIV), eating raw or undercooked crustaceans (Norwalk virus), getting bitten by a mosquito (West Nile virus). To my knowledge, viruses can only be transmitted through water with high fecal content; and purifying or boiling will eliminate any water-borne virus.

2¢ more --
Glen

Sundsvall · Jun 18, 2004

storyville said:
Joe,
Sundsvall,

Viruses are not a concern until they have been cultivated in a host, yes? As for "immortality": Medical professionals I've spoken with (including my neighbor, a virologist in the Biology Dept. at UC Irvine) and commonly available text sources (e.g., CDC website, Lifespan.org, MadSci.org) all refer to the "lifespan" of viruses, where and how long they "live," how they can be "killed" (or better, avoided), etc. Do you believe this language is misleading?

Last note on viruses: Someone with more knowledge can chime in, but even in underdeveloped countries I believe viruses are vastly more likely to be transmitted by means other than water: e.g., not washing hands before eating (Hepatitis A), unprotected sex (Hepatitis A, HIV), eating raw or undercooked crustaceans (Norwalk virus), getting bitten by a mosquito (West Nile virus). To my knowledge, viruses can only be transmitted through water with high fecal content; and purifying or boiling will eliminate any water-borne virus.

2¢ more --
Glen

At any given moment there are a variety strains of strep and cold causing viruses. They are not alive, so they cannot be killed.

Unprotected sex and other body fluid transmission results in Hep B or C. Hep A comes from contaminated food.

HIV needs direct access to the circulatory system.

Viruses are strips of RNA and DNA. They invade a host and add their code to the messenger RNA to cause rapid production of the virus's DNA/RNA via mitosis. They also mutate the cell to enable it to attack surrounding cells and inject the viral code into them.

The lifespan the texts are referring to are the time it takes viral infected cells to die. The viral code itself doesn't die. It just blows in the wind.

Boiling water has enough power to denature virus code and destroy them. Water filters will not affect viruses at all.

Water purifiers use chemical and/or electrical catalysts to denature viruses.

This is the radical difference between purifiers and filters.

Just didn't want anyone to wonder why their water filter didn't clean out the viruses in the water.

Grapevine · Jul 9, 2004

Sorry for resurrecting this thread. I haven't been to this corner of the forums in a while so I had a lot of catchup reading. Thought I'd share what little I know about carbon adsorbsion. My knowledge comes from aquarium keeping, which is strange to apply to survival skills but we fish nuts are nerds when it comes to water filtration. I'm not too well versed in the real scientific geek stuff though.

Activated charcoal (actuallly carbon is the more correct term) adsorb certain molecules. Adsorbing involves a chemical link and not just a physical trapping, which would be absorbing. The carbon is very porous and as water passes through the minute pores, some chemical compounds would be trapped by oppositely charged molecules along the walls of the carbon's surfaces and pores. Once trapped by such electrical means, the chemicals can't physically be flushed out by water flow. What chemicals get trapped depend on what sort of carbon is used, how small grained it is, and how it was prepared. Not all activated carbon is the same.

I would be fairly confident that pesticides would be adsorbed by most of the activated carbon in water filters. The problem would be volume. The more contaminents, the quicker the carbon gets exhausted. Things like particulates (dirt and other things microscopic but not down to the molecular level) can also simply clog the carbon from adsorbing. Particulates should really be prefiltered out by a physical small mesh type filter so that the carbon can last longer. I don't know if those bottle systems do that. The amount of carbon that looks to be in those filters don't seem to be much. But the manufacturers should give some indication of how much water at varying quality you can expect to filter with one unit before you have to replace, no?

I frankly wouldn't be too concerned about chemical filtration. Unlikely that the volume of water you're concerned about, for the short amount of time you'd be drinking that volume, would be so saturated with pesticides as to be a problem. The carbon will get rid of foul tastes and odors though, which might be a good thing for a casual hike, but probably not that important in terms of survival.

Bacteria, viruses, and other biological nasties will not be filtered by carbon unless they were somehow physically trapped by the density of the carbon grains being packed tightly. Not a very sure method at all and shouldn't be relied on. Water finds its path around clogged areas and will sweep with it things not adsorbed.

I think a combination of carbon type filtration for chemicals, and water purifying for biological contaminants, is best if you're very unsure of the water supply. But do not do it simultaneously. Carbon may very well adsorb the iodine (not sure). It would certainly adsorb chlorine. I would do the tablets first, then after the appropriate time for the tablets to work run it through the carbon filter. If there weren't bad chemicals to be adsorbed, at least it'll adsorb the bad taste some.

If choosing between systems, I think the tablets are more important.