Feb 28, 2007 at 8:01 pm #1222099
The US Army Center for Health Promotion and Preventative Medicine has released a report on the performance of commercial individual water purifiers (IWP)
The test was done on a scale and level of detail that only the bottommless pockets of the US government could fund. They tested 48 mechanical filters and 14 chemical disinfectants against 6 test criteria.
The results are summarized here:
"(1) Consider the SweetWater® Purifier from Mountain Safety Research, Inc., as the highest-scoring overall filter-based IWP.
(2) Consider the Micropur MP 1 Tablets from Katadyn North America, Inc., as the highest-scoring overall disinfectant-based IWP. It removes all four pathogens of interest, and is
This should give smug satisfaction to those of you who chose these two systems basd on your own research, and valuable guidance to those of you still considering which system(s) to buy.
You can see a summary here;
And follow the "Project Report" link for the full 664 page report.Mar 1, 2007 at 2:24 am #1380534
I believe the Sweetwater Purifier is really a two-step system. First, filter with the pump filter (i own the filter and have used it), and then treat with a Sweetwater chemical (bleach-like, IIRC).
As i said i've used the filter, and when the water is really, really suspect, i've dosed with AqM instead of the Sweetwater "bleach"(???) – "same difference", as the oxymoronic saying goes.
Alternatively, i've used UV-C as the second step after filtering. Chems & UV-C alone, at the dosing levels normally used, will NOT handle larger, more rarely encountered parasites.
As i've mentioned multiple times of the past 2+ yrs, a two-step approach is the only surefire way of theorectically eliminating ALL potential pathogens.
Boiling for a long enough period of time – 2-5 minutes to make sure one nails everything. However, simmering for 10minutes is required to be sure to denature some thermolabile exotoxins which are NOT expected to be encountered in water, but in some contaminated foodstuffs. Some endotoxins encountered in contaminated foodstuffs are thermostabile and aren't affected by heat. Boiling is a sufficient, but fuel inefficient one-step means of purification. This 2-5 minutes is probably a better guideline for a disaster situation (raw septage contaminated water supply for instance) than for normal not-pure backcountry water – in which a "pasteurization" approach might be sufficient, just heat the water to 180F (hard to judge w/o a thermometer) to 212F (easier to visually determine) and you're done.
now, however, there are some filters (First Need Deluxe, and Katadyn ExStream, Sawyer Purifier) that contain an antiviral stage and purport to be a one-step solution.
Chem. contamination is addressed, in part, with an activated charcoal stage in the First Need & Katadyn products. My Sweetwater system doesn't address this type of contamination.Mar 1, 2007 at 4:52 am #1380542
@garkjrLocale: Southwestern Ohio
Isn't the Army the same folks who, at the height of Vietnam, ran an ad asking "Can you qualify to be an infantryman?"; at the time, walking and talking pretty much did it. (Just a humorous aside from an Air Force vet – we also bait the Navy by getting them to tell us the difference between "ship" and "boat"; after the lengthy explanation, we shrug and say, "Oh. We just call them all "targets.")Mar 1, 2007 at 5:08 am #1380543
Ben 2 WorldParticipant
@ben2worldLocale: So Cal
I toured one of those new fangled 'invisible' frigates one time. I asked three different sailors about the correlation between 'knots' and 'mph" — and I got three different answers. Scary.Mar 1, 2007 at 6:30 am #1380551
As told to me by a current Marine so consider the source:
If you ask the military to "secure a building"…
The Marines will go room to room until all the bad guys are gone.
The Army will set up guards to make sure no one goes in or out.
The Navy would put up yellow caution tape around the building.
The Air Force would make sure the building lease is set for the next 4 years.Mar 1, 2007 at 8:01 am #1380560
@garkjrLocale: Southwestern Ohio
Naturally, the Air Force is interested in the lease. Remember when they first started talking about a neutron bomb? It was defined as a weapon that would kill everyone, but leave the real estate intact. Very much unlike the old-style nukes I was involved with: Q: Can you attack the same place twice with a nuke? A: No. After you attack it the first time, the same place isn't there anymore.Mar 1, 2007 at 8:09 am #1380562
back in the day, the USMC had this recruiting slogan, "The Marines are looking for a few good men!". We used to say then, that the Marines already have a few good men,…Navy Corpsman!!!
The Corps is great. Semper Fi!Mar 1, 2007 at 7:40 pm #1380651
If I am redundant, I apologize. Hit a wrong button and may be posting twice.
The USACHPPM document is large but does not stand alone. It is also a bit aged by now. The products were used according to the manufacturer's directions. The Engelhard pills are on 4 hour time release in order for them to release their faux chlorine dioxide over time to accomodate type2 water–you know the dark mud puddles that no one drinks anyway. Anyway, there would be a full four wait for a full release of chemicals because the pills are set up to release over time. The pills are also foul unless they are left to sit over night. Does any filter that can filter most virus not clog very easily? This does not seem a practical solution. Seems the best approach would be a very simple filter combined with a chlorine dioxide product OR use pretty clean water and use chlorine dioxide.
The main thing I would like advice from Dr.Jordan–Why is the binding chemical in the Engelhard pill dichloroisocyan….. specifically forbidden for human consumption in EU? I was told at the OR show that this was the basis for the development of KW. Anyone know this history? Also I was told KW was made better this year but did not see an announcement.
Hey, we've come a long way past iodine and bleach but the pathogens are mutating also.Mar 2, 2007 at 2:12 am #1380687
@rcaffinLocale: Wollemi & Kosciusko NPs, Europe
> The US Army Center for Health Promotion and Preventative Medicine has released a report on the performance of commercial individual water purifiers (IWP)
> The test was done on a scale and level of detail that only the bottommless pockets of the US government could fund. They tested 48 mechanical filters and 14 chemical disinfectants against 6 test criteria.
Try filtering through a bandana and using a SteriPEN Adventurer. Kills everything, takes 90 seconds for 1 litre. Light weight. No residues.
Coincidentally, we have just published a Review of the Adventurer… :-)
CheersMar 2, 2007 at 2:20 am #1380690
>>"Does any filter that can filter most virus not clog very easily?"
good question. would seem that it would.
now, i'm sure if a very specific filter/product is being thought of in that quote? generally, though, with the possible exception of Sawyer's claim to actually "filter" viruses, the virus particles are NOT filtered (as in a mechanical barrier filter – y'all, know, it's the type that can clog).
some of these "one-step" filters/pumps use an iodized gel stage as the final stage after filtering to eradicate any virus particles present. it is not a filter, so it can't clog.
speaking of filtering, to avoid clogging, filtering can be accomplished in "steps" with a larger mesh pre-filter (which is very easily cleaned, even w/o resorting to backflushing) preventing larger matter from entering the filtering inlet tube, a smaller mesh pre-filter to handle sediment and such can come next, then the actual sub-micron filter to remove the eggs of larger parasites, protozoans, protozoan cysts, and bacteria (generally considered to be about the smallest organisms removed by a simple mechanical barrier filter of any configuration/design).
the one or two stage easily cleaned prefilter(s) helps to keep the sub-micron filter from clogging as readily.
UV-C (90s or less treatment time) or chems (generally just 15min dwell time after introduction into the filtered water) can then be used to eliminate viruses.Mar 2, 2007 at 9:57 am #1380754
@bjamesdLocale: South Coast of BC
Can someone enlighten me here?
A virus cannot live outside of another cell. So while the virus may be incredibly small, the effective size of filter or barrier required is the size of the cell the virus is living in. In fact, virii do not technically fit the definition of "alive" since they are not able to feed or reproduce themselves. They rely on the host cell to do that.
I remember the hubbub in the 80's when someone calculated that the pores in condoms are actually larger than the HIV virus. It was a frenzy until someone who had taken Grade 7 Biology pointed out that the pores needed only be smaller than the sperm cell in which the HIV was living.
Are waterborne virii somehow different? This is obviously an issue because people supposedly still get sick using 2 micron filters. Are waterborne virii living in cells that are smaller than 2 microns?Mar 2, 2007 at 11:05 am #1380772
Like Brian said, a virus doesn't conform to the standard definition of a living creature – no reproduction (apart from a host of an entirely different nature), no metabolism, no respiration (this has broad meaning and is sometimes lumped together with metabolism – don't think of this as only being identical with a human or a fish breathing), no response to stimuli (this can be rather broad in scope and meaning). So, the subject line of this Post is, admittedly, in one sense, a misnomer.
Viruses (or Virii, if you prefer – both are correct) enter cells through virus receptor sites on the cell. The protein sheath of the virus is able to afix itself to a somewhat complementary virus receptor site and injects its DNA or RNA (a virus has one or the other, not both) into the host cell. Some viruses also are encapsulated in a membrane which is often similar to a host cell's membrane or membranes of a host's cell's intracellular organelles.
Inside the host cell is where it takes over and splices the invading virus DNA or RNA into the host cell's DNA, and forces the host cell to replicate copies of the complete virus particle – nucleic acid core (DNA or RNA) and the protein sheath. Though some viruses may remain dormant for some time and not begin this replication cycle which results in destruction of the host cell.
When a sufficient number of virus copies are replicated, known as the "burst size", the cell can't hold anymore and ruptures, releasing the virus particles into the environment (that environment varies widely, it could be the blood stream, water, etc). For reference, the burst size for the T5 bacteriophage which infects the E. coli bacterium is ~200. The virus particles at this point are NOT inside of any cell, but for a time are free floating/roaming hoping to contact an acceptable host cell with an appropriate virus receptor site that is complementary, so to speak, to a portion of the virus's protein sheath, and the cycle begins all over again.
When free from the confines of a host cell, the virus particle is very susceptible to destruction from ionized chemicals, UV light, electro-static discharge, etc. Often, (always???) they are somewhat protected by other substances with which it may be associated such as mucus, droplet nuclei, etc.
Viruses range in sizes from 20 or so nanometers up to a bit over 200 nanometers, IIRC (but you should verify this as my memory is not too good anymore). In fact, there is actually some overlap in sizes b/t the smallest virus particles and the largest proteins! I've never come across the pore size of an expanded condom, so, i'll take your word for it.
Does this answer the very astute question that you posed?Mar 2, 2007 at 9:02 pm #1380838
@bjamesdLocale: South Coast of BC
Fascinating. I guess my biology teacher was oversimplifying.
Thanks for the info!Mar 3, 2007 at 2:51 am #1380855
@wildyorkieLocale: New York
I have read rhe review of the Steripen, and I do not believe that tetster evaluated the micirobiolgigal effiency of the purifiers. If someone has any field use data which would confirm the efficeancy of the Steripen then please enighten us.
Otherwise, it woud seem that the General Ecoolgy First Need Deluxeu purifer offers the best pepeformance without the addition of ididone or chloriene tearement. Moreoever, if a Micropur cholrine dioxide tablet is used to pretreat the water before rununning it through purifier, the result should provide
excellent qualiity water.
Perphaps the optimiun combiation whold be to use the the First Neeed Deluxe Purifier Ourifiet with the Katadyne MicroPur tabllet. The First Need coulb be used to treat water already teateted with Kayadyns MiroPur tablets. Hoopefuly this will revove any resisdual chlorine which may be a souce of mutagents or carcinsogens. The US Army cricicism was thet they were unsure how the Firts Neeed waould at perforn at high flow rates.Mar 3, 2007 at 5:07 am #1380858
My preference (it's NOT a dogma intended to be enforced on everyone) is to filter first, then treat w/either UV-C or chems.
Both modalities work far better on treated water due to the elimination of very tiny debris and biofilm that could shield the lil' buggers from both UV-C and chems.Mar 3, 2007 at 10:39 pm #1380944
@danepackerLocale: Mojave Desert
I will be using Katadyn tabs this summer.
1st I'll "filter" my water W/one (or 2 if the H2O is trubid) cofee filter in a funnel. Then add the Katadyn tabs. This will be a before bedtime job to give the tabs plenty of time to work all night.
EricMar 4, 2007 at 2:30 am #1380964
In fact, i recall DrJ mentioning this one to two years ago (he used AqM though, but it still applies to your choice of chem). What DrJ mentioned to save weight is that you could even HALVE the dose and DOUBLE the contact/dwell time – thus, stretching out the chem you are carrying to last twice as long for the same weight of chem. You won't even notice the added contact/dwell time since you'll be sleeping.
My only suggestion is to NOT take the HALVE/DOUBLE concept too far. A certain minimum level is probably required to accomplish your purification goal – even given unlimited contact time. Also, apropos to water purification is the Industrialist's motto, viz. "The solution to pollution is dilution!". It applies to the minimum level of chem req'd to properly disinfect water also.Mar 4, 2007 at 5:04 am #1380974
@einsteinxLocale: The Netherlands
Every now and than I like to call/mail sales reps to ask them difficult questions. About a year and a halve ago I asked the MSR sales rep and the Care+ sales rep to ask them about chemical water treatment and also about pore size of filters.
One of my arguments was that there are theories that virii have traveled through space on/in a meteor than crashing into planet earth and surviving than sparking live on earth.
I also reccolect to hear about a test (could be a myth though) where virii were put on the tip of a bullet that was than shot into a concrete(?) wall and surviving the many thousands of G-force.
My argument was that if a virus can survive that than why would a mild treatment as a chemical kill a virus?
Besides a virus isn't alive so how can you kill styh that's not alive.
Here's what I remember from the MSR guy, paraphrasing big time:
Virii our found in three forms: within cells, alone and a bunch together called a macro virus. IIRC anthrax is a macro.
The chemical will kill the cell and a virus won't survive without one for long, so a chemical will get rid of that virus for you. Cells are usually bigger than 0,2 micron so they'll be filtered out.
A single virus can excist but is incapsuled and will be inactive and have a short live. Leaving your water for half an hour will be enough for these virii not to do you harm (I'm not sure about this one)
Macro's are bigger than 0,2 microns so can be filtered. He specifically mentioned that the MIOX will "kill" anthrax though he mentioned a longer sitting time of up to 4 hours. I also remember that I mentioned this when I started visiting these fora and someone from MIOX responding and disagreeing on such a long sitting time.
So filtering and/or chimicals should make your water drinkable.
I aslo asked about protozoa. These are bigg so should be stopped by any filter. I don't remember what they said about the effect of chemicals on protozoa.
I think a reason why people still get sick using 0,2 micron filters could be cross contamination.
EinsMar 5, 2007 at 8:24 am #1381123
1. i've heard about the "bullet" test. i think that HEAT is more of a factor during firing and during impact, than the G-forces during deceleration. I have no opinion about this test, though i'm a skeptical due to the heat generated. Protein begins to be denatured, or "cooked" so to speak – it's quaternary structure begins to change/"unravel" (as some have termed it) when exposed to even 130F (you can cook an egg even if the temp never rises above 140F). So, i have some doubts about the "bullet" test. Partially-attenuated (so-called "live" vaccines) and fully-attentuated (so-called "dead" vaccines) are sometimes made so by exposing the viral antigen in the vaccine to heat (though other means can be used also – e.g. chemical and even nowadays genetic).
2. Anthrax is definitely NOT a virus. I've cultured and examined it a number of times back in the very early 70's – way b/f the days of bio-terrorism. It is a relatively large gram-positive bacillus (i.e., rod shaped bacterium, as opposed to cocci/spherical-shaped and spirochetes/corkscrew-shaped/spiral-shaped) with a taxonomic name Bacillus anthracis. It is an aerobic "cousin" of the anaerobic pathogens Clostridium botulinum (etiological agent of botulism), Clostridium perfringens (causes "gas-gangrene" – very nasty if you ever have the chance to see and/or smell gas-gangrene), Clostridium tetani (the etiological agent of tetanus).
3. As i mentioned earlier, viruses can be found outside of host cells. Most don't last too, too long (hours or days). As such they are very susceptible to destruction by ionized chemicals, UV light, and electro-static discharge.Mar 5, 2007 at 4:32 pm #1381174
@robertm2sLocale: Lake Tahoe
Re: "One of my arguments was that there are theories that virii have traveled through space on/in a meteor then crashing into planet earth and surviving, then sparking life on Earth." The recollection of my senile, alcohol-ravaged brain is that while organic chemicals found on space debris might have seeded Earth with the building blocks of life, no virii or bacteria have ever been found on objects from space. I believe that Earth's first life must have been capable of reproduction without the help of another organism's cell, since by definition there were no other organisms. I think they say that most of Earth was cleared of delicate, complex organic molecules by the constant bombardment of asteroids and other objects, which turned the surface white hot. After cooling down and developing some surface water, perhaps organic chemicals from space combined with the water and were energized by lightning or hot vents, producing ME, and, oh yeah, other life. So, perhaps the space organic chemicals were assembled without ever being heated excessively?Mar 6, 2007 at 1:33 am #1381227
@rcaffinLocale: Wollemi & Kosciusko NPs, Europe
> I have read rhe review of the Steripen, and I do not believe that tetster evaluated the micirobiolgigal effiency of the purifiers.
You are quite right: I did not do microbiological tests myself. But there are several lab reports on the SteriPEN web site covering such tests, and I relied on those. I do not believe such reports get forged (the EPA would be on them big time!).
> If someone has any field use data which would confirm the efficeancy of the Steripen then please enighten us.
I am not sure what you mean here. Are you asking people to do microbiology tests in the field? Hum…
> General Ecoolgy First Need Deluxeu purifer offers the best pepeformance
Oh, it works fine: I have one. But the filter cartridge has a quite short life and the system is quite heavy – heavier than I am willing to carry if there are lighter suitable alternatives.
But, ymmvMar 6, 2007 at 2:33 am #1381233
@einsteinxLocale: The Netherlands
PJ and Robert,
Thanx for the info. Better answers than both sales reps I called. Now I don't say that virii are as resilliant as I mentioned in my previous post. I just like to ask these sales reps difficult questions to see if they can give me a good answer, so enhancing my knowledge, making it easier for me to help my customers.
EinsMay 14, 2008 at 12:15 am #1433177
@kreppartLocale: Pacific Northwest
The army report doesn't list Potable Aqua chlorine dioxide tabs, is it safe to assume they are equally as effective as the MicroPur tabs? Someone above in the thread said that all the tablets are made by the same manufacturer so if that's true it would stand to reason they're identical or nearly so.
Also is there any concern using chlorine dioxide on water with lots of tannins?May 14, 2008 at 6:08 am #1433191
I doubt the tablets are made by the same manufacturer. I bought some potable aqua tablets. The packaging is not as good to me and my tablets began to crumble in the packaging before I used them. Maybe I had a bad batch, but I won't be using them anymore.May 14, 2008 at 8:14 am #1433204
@dgpostonLocale: Texas / Colorado
These are the exact items I use based on careful research. I'm so proud of myself. :)
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