Water filters and their efficiency

Discussion in 'Functional Gear & Equipment' started by duane, Sep 11, 2019.


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  1. duane

    duane Monkey+++

    In going down the Woodpile rat hole today, he mentioned a report on water filters, Water Filter Test Results | Best Choice for Backpacking, Survival & More , if you read one report on filters, you must read this one. Some of the most expensive do not filter viruses, some of the cheapest have the highest ratings, overall very well done. The test also mention that there are no official standards and while the advertising may be 100 % true, what they don't mention could kill you.
     
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  2. SB21

    SB21 Monkey+++

    I haven't read it all yet , but that's about the most info I've ever seen on water filters in 1 place . Great post .(y)
     
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  3. Bandit99

    Bandit99 Monkey+++ Site Supporter+

    Very well done article, actually, it's more a 'tutorial.' I got Giardia once before because we weren't boiling our water long enough, was climbing in Nepal so wood and gas was scarce; needless to say, never want that again. It's possible, I got Hep A also from water but I will never know that for sure, that was in Bosnia, also something I never want again... So, I have lots of LifeStraw and water bottle filters. My water storage is a 1500 gallon cistern but I know that is not near enough but one never has enough. The good news is I have a very deep well, 400+ feet so as long as I can apply power and fill the cistern once a day, I'm good. The bad news is I share the well with 5 other neighbors so I don't have full control over it. Back on topic...

    In my opinion, the most important bit of provided information :
    1. "Purifiers and filters are technically different...Water purifiers must remove, kill, or inactivate all types of disease causing organisms from the water, including viruses, according to the EPA. Filters, on the other hand, do not have to protect against viruses."

    2. The NSF standards in clear English plus a direct statement "NSF/ANSI 42 and 53 standards are not sufficient for portable water filters..."

    3. The number of purifiers/filters tested and their no nonsense findings, again, presented in plain English.

    I have saved this document and will refer to it when I select my next Purifier am going to look at a couple that ensure deletion of viruses like the Grayl, LifeStraw Mission or Renovo and also want to look into the Katadyn which I am not familiar with...

    Thanks, Duane!
     
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  4. john316

    john316 Monkey+++

    looks great................thanks a lot
     
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  5. DKR

    DKR Raconteur of the first stripe

    Ran across this recent (2019) piece on portable water filters.

    Duplicate of the above OP Post..
     
    Last edited by a moderator: Oct 26, 2020
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  6. Oddcaliber

    Oddcaliber Monkey+++

    Got a Katadyn and a Berkey. You never know what is in the water.
     
  7. DKR

    DKR Raconteur of the first stripe

    I would caution folks that have a virus issue with their water that a portable filter is like shooting craps with your health. I filter (Sawyer) then treat with chlorine dioxide. 30 min later, good to go unless the water is ice cold. Then you are most likely going to boil it anyway, so good either way.

    The reason iodine gets a bad rap (and is banned in the EU) for water treatment is the length of time need to kill Cryptosporidium (Protoza) and other parasites in the water.
    [Efficacy of iodine water purification tablets against Cryptosporidium oocysts and Giardia cysts - PubMed] "Only 10% were inactivated after a 20-minute exposure to iodine according to manufacturer's instructions; even after 240 minutes of exposure to iodine only 66-81% oocysts were inactivated. These data strongly suggest that iodine disinfection is not effective in inactivating Cryptosporidium oocysts in water. Because this organism is common in all surface waters, it is recommended that another method of treatment be used before ingestion."

    A Guide to Drinking Water Treatment and Sanitation for Backcountry and Travel Use | Camping, Hiking, Travel | Drinking Water | Healthy Water | CDC
    Money quote:
    If boiling water is not possible, a combination of filtration and chemical disinfection is the most effective pathogen reduction method in drinking water for backcountry or travel use. Manufacturer’s instructions must be followed.
    This CDC product points out that boiling is the most effective way of treating water.

    The Big Army view on iodine in water treatment (very sensitive to water temp)
    https://phc.amedd.army.mil/PHC Reso... of Individual Water Purification Devices.pdf

    As a side note, chlorine dioxide is now being sold as a surface disinfectant for COVID vurus.
    disinfection for virus and bacteria

    and in dental offices - Clinical use of Chlorine dioxide in the prevention of coronavirus spread through dental aerosols. some good data buried i the article.

    Be careful out there.
     
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  8. ColtCarbine

    ColtCarbine Monkey+++ Founding Member

    It's my understanding that boiling, disinfection and/or UV is what's needed for viruses not filters. Filters can reduce/eliminate bacteria and protozoa depending on the size of pores in the filter.
     
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  9. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    Correct, well almost... Most viruses are to small to get trapped in a Regular Filter... However an RO Filter will get some of the bigger ones..
     
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  10. DuxDawg

    DuxDawg Monkey+

  11. arleigh

    arleigh Goophy monkey

    I have a 2 filter system on my house, A house hold filter charcoal. and Britta filters on the kitchen and bathroom taps.
    So far as ou door filtering, it is run through a coffee filter first then through a Soyer. Or depending on the water's condition Boiled first then coffee filter and Soyer filter.
    Under less than optimal conditions using old storage, I have a 5-gallon bucket with screens and charcoal, washed sand and gravel as a pre-filter for the house, and the Britta filters secondarily. They are charcoal as well.
     
  12. 3M-TA3

    3M-TA3 Cold Wet Monkey Site Supporter++

    I have a Big Berkey w/ the finer black filters for home or camp use and Sawyer filters for mobile use. The Sawyer is great because you can attach it directly to most grocery style water bottles, like Smart Water, and then squeeze the water through the filter on demand. It can also be cleaned by back flushing it.

    I also have 3 or 4 bottles of Polar Pure, which is a super saturated iodine solution that has a big chunk of iodine to keep it recharged. When I was backpacking through Nepal decades ago I used my own home made version of Polar Pure as we could buy USP iodine those days. It kept me from getting sick there and that is saying a lot. Everything is most parts of rural (and even urban) parts of Asia I've been in seem to either be getting shat upon or already covered in it. Get your water from a river or stream? You don't even want to see what's upstream. Mainly, find out what part of the river the local village uses for toileting and go upstream of there. Yeah, iodine did the job just fine, even when I had to use water that had tiny things swimmin' in it.
     
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  13. DKR

    DKR Raconteur of the first stripe

    LOL - If you can see your water moving in the cup....it needs more work.
     
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  14. 3M-TA3

    3M-TA3 Cold Wet Monkey Site Supporter++

    The stuff was moving in the cup before the iodine and thankfully not after I gave it enough time to do it's job. No other choice for water that I could get to without water. Can't easily get USP iodine anymore I understand because it's used for producing one of the common street drugs. I do have to say for those considering using it that it does have a particular taste.

    Two of the people I was hiking with decided they didn't like it well enough to be strict with water treatment and paid the price. I also wound up chipping in some extra Imodium. The rest of us wound up looking for appropriate leaves until we found a village that had toilet paper. Locals just did their business in the river including cleaning using their left "unclean" hand, and I think just stocked it for us westerners.

    BTW. this is why you pass people on the right in Indo Asia. Passing on the left "unclean" side is very much an insult. Since I'm neitherhanded (equally clumsy with both hands) I accidentally paid someone with my left hand in a market in Kathmandu. I can still see the look in his eyes; not anger but humiliation. It took a while to apologize sufficiently, but I suspect he was being overly polite.
     
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