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Thread: Water filtering and chemical treatment

  1. #1

    Water filtering and chemical treatment

    Hi everyone,

    I have a question about treating water in the UK. I have read lots of advice about where to source water from for filtering and purification and that is to get it from the clearest possible flowing source.

    I was recently camping in South-east England and wanted to test my new MSR trailshot and chlorine dioxide tablets (I've never treated water before), the stream going through our campsite was fairly murky, surrounded by grazing animals and slow flowing. I decided not to test it on this water and wait until I was somewhere a bit more "wild". But, I am wondering, are the filtering and chemical treatment methods good enough to make this water safe? I imagine the risk would be fertiliser in this particular stream, and I understand nitrates can not be filtered out. But are they harmful to us? I am thinking of a hypothetical situation where this really was the only option.

    Thanks

  2. #2
    Ultra King Diddi's Avatar
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    Never drink or filter water below farms only above the highest.

  3. #3
    Quote Originally Posted by Diddi View Post
    Never drink or filter water below farms only above the highest.
    So even if it was the only option, in some extreme hypothetical situation, and the only other option was to not have any water? It can't be made safe by filtering and adding chemical dioxide tablets?

  4. #4
    I'd rather boil water in those extreme hypothetical situations. But it's better to avoid such.

  5. #5
    ‹bermensch
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    Then look ......Drinksafe Systems........Travel tap for really dirty water sources.........I'm still here.....

  6. #6
    Mini Goon
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    In terms of biological hazards, filtering and chemical treatment will do it. But with some farms there is a risk of chemicals which they won't usually solve. Nor will boiling.

    For most streams I'm happy with filtering alone.

  7. #7
    Super Moderator Metric Kate's Avatar
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    Yep, I'd filter water in preference to using chemical treatments, but I'd be cautious about water with potential pollution from farmyards!

  8. #8
    Mini Goon
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    This is an interesting chart: https://www.cdc.gov/healthywater/pdf..._Treatment.pdf

    It shows that boiling is the most sure, single-step, way of disinfecting water and is equivalent to a combination of filtering and purification tablets.

    However you have to look at what size filter you use. The filter sizes mentioned in that document are 1.0 and 0.3, whereas the Sawyer Mini filter goes down to 0.1 so should be even more effective against bacteria and protozoa, but not viruses.
    From what I can tell, the main dangers a UK backpacker, drinking from streams is likely to face are:

    1. Cryptosporidium, a protozoa which is commonly carried by sheep and other livestock. Given that the livestock use the majority of "wild" areas in the UK, this is a realistic threat. Something like 5500 cases a year. A decent filter should deal with this easily as it's quite a large organism in the scheme of these things.
    2. Weil's Disease, a bacterial infection spread by rat urine. More rare but potentially very serious. A suitably fine filter handles it.
    3. E.Coli, bacterial, again associated with livestock.

    There are other organisms, both parasitic and bacterial but these appear to be the main ones.

    In addition, there are risks where human sewage enters the chain. At that point you need to start worrying about viruses like norovirus and more worryingly hepatitis. Filters do not deal with viruses so are not suitable where human waste contamination is likely.

    So overall, a decent filter, used in the right locations and used carefully should be enough. If human waste is possible you can add tablets as well. If you're boiling for meals or a cup of tea then that pretty much sorts everything anyway. If there is chemical pollution, you're probably screwed.

  9. #9
    Ultra King Diddi's Avatar
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    *"If there is chemical pollution, you're probably screwed."
    Yep its the pesticides that'll get ya.
    Like smoking a cigarette the chemicals are there and you may "still be here" doesn't mean its not damaging you inside.

  10. #10
    Ultra King Mole's Avatar
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    Filters with a carbon filter element will significantly reduce chemicals in water.

    Many people have them in their kitchens to make tap water taste acceptable. ( Though these filters don't do bacteria/virus.)

    Drinksafe systems ( Seychelles filters) and , lifesaver bottles have this feature. As do others.
    I would use this type of filtering for lowland waters below farms etc.

  11. #11
    ‹bermensch
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    If you read the 'Technology' title on the Drinksafe Systems, explains it all....supplied to disaster areas.
    When I know water sources will appear undrinkable, I use the Sawyer first to take out the main sediment...so the Travel tap doesn't have to do this...extends life of the Travel Tap filter.
    The water is squeezed through the Sawyer into the Travel Tap and then again filtered into the saucepan/pot.
    Then boiled......again, as Mole says........guaranteed......

    BUT, remember to flush through the Sawyer after use or it will clog up.
    Dont let any filter dry out in storage either.....I store cool but moist and flush out often in clean water...but then I am using these filters every week.
    The filter of the Travel tap doesn't last long but is very safe.....

  12. #12
    ‹bermensch
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    AND....never use chemicals as a back up now.....used to in Nepal...iodine, but its been banned now...still got an emergency supply but it HAS to be an emergency to use this stuff.
    Chlorine doesn't kill everything......
    Modern day filters the answer now.....

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