Your choice for water purification

[Danneaux]

Hi All!

Which methods do you use to purify water, and why did you choose them over others?

Going through my gear lockers this afternoon, I am surprised at how much gear is devoted to water purification. I often travel in areas where water is suspect -- both for alkali contamination and for impurities such as water-borne pathogens, blastocysts, etc. For alkali, there's really no redress except avoidance, after first checking to see if it leaves a red mark after sitting on the skin for 30 or so minutes or -- even better! -- by using the pH test strips I take along for that purpose. In case of accidental ingestion, I also carry a small bottle with the same mix used by pioneers on the Oregon Trail to address alkali poisoning: vinegar, flour and water (it works!). Nice summary here: eHow.com http://www.ehow.com/list_6137988_diseases-people-oregon-trail.html#ixzz1nujfsV8F For an interesting story about how wild ducks in these areas can be affected (note the date), see: http://www.google.com/url?sa=t&rct=j&q=%22alkali+poisoning%22+from+water&source=web&cd=2&ved=0CDAQFjAB&url=http%3A%2F%2Fwww.fws.gov%2Fnews%2Fhistoric%2F1918%2F19180711a.pdf&ei=gipQT8mhKcKZiQKA_9m1Bg&usg=AFQjCNEImrn8SwHFv1P0dOxHBghJJWgpYg&cad=rja

For general water purification, I use a *mix* of methods, depending on water turbidity (cloudiness) and source:

1) Filter out sediments using a pre-filter or by settling and skimming, then...
2) Use Steri-Pen with pre-filter, adding a pinch of salt if water mineral content is too low for good electrical contact (I use the Steri-Pen Classic; the high-capacity rechargeable AA cells powering it can be recharged with my dynamo via the Tout Terrain The Plug 2).
and/or
3) Boil water to a rolling boil, cool, settle, decant.
4) Use chemical means -- chlorine or iodine pills or iodine drops, extending the waiting time if water is cold
5) SODIS -- SOlar DISinfection of water using my 1.5l clear plastic bottles. See: http://en.wikipedia.org/wiki/Solar_water_disinfection (check out the relate links available here). This works surprisingly well if it is hot and sunny and you wait long enough. And have clear bottles.

I used to also occasionally use a silver/iodine resin gravity-feed drip filter, but it was bog-slow, clogged often, and handled only a small quantity at a time.

I don't use the popular ceramic or other filters, as I have not had much luck with them. They seem to clog sooner or later, usually when they are most needed. The pump kind either required enormous effort to pump after a short while (and frequent cleaning to try and restore them, even when they only filtered settled water or pre-filtered/strained water) or simply clogged (if the gravity-feed type). Even if I took great care to not drop the ceramic filters, they ventually cracked, apparently from the severe vibration encountered on my version of ripio. The Steri-Pen lets me drink from horse and sheep troughs, wall seeps, springs, and scummy puddles contaminated with animal urine (zapping it after some pre-filtering and settling). It may not taste good, but it hasn't hurt me so long as I take care to use the Steri-Pen correctly and am cautious about incidental contamination.

With any method, it sure is hard to avoid incidental contamination...say unfiltered or unpurified water caught on bottle-cap threads, or opening the squirt nozzle on a bottle of clean water using fingers still-wet with contaminated water. I am really carefull to dry off a bottle so impure water won't run up the side as I tip the bottle to drink. And, I always clean my hands before and after purifying water. I don't have an obsessive-compulsive nature, but I sure use care to avoid getting water-sick in the middle of nowhere.

For travel in towns with known-good water supplies, I have found I sometimes develop an upset GI tract unless I take care to sample the water frequently as I travel. My pet theory is I can adjust to small changes in adjacent water supplies, but have trouble adjusting to changes in water sources located some distance apart. It may just be a comforting thought, but it seems to work for me.

So, what's your preferred method for treating sketchy water? Any methods that just plain didn't work? Any horror stories to serve as a caution?

Best,

Dan.

[mylesau]

Purification tablets (Aquatabs) and Solar - 2 x 1.5l clear plastic soft drink bottle strapped to the bike.  That's it for me.  Never had problems and have had to resort to some dodgy looking water at times.

Floaties are just added protein and dirt/turbidity gives it some character...

I would probably think this through a bit harder if I were travelling through certain parts of the world.

My view based on experience of others I know and respect:
* I wouldn't bother with the likes of a Steri-Pen - a bit hit and miss and I hate the idea of batteries.
* Filtration works - but keep it simple - a 'soft' bag with a filter using gravity will outperform/outlast a pump every time.

My views - not suggesting they are right for anyone else.

[Pavel]

I'm still holding out. There has to be a company that is hard at work on abetter system which corrects the major flaw in all of these "old" purification systems. They will get my business - like I said, I'm holding out.

Pond water in one end, beer out the other end or nuthin!!
They should call it "the Tap". How long, how bravely have we all waited!

[stutho]

Hi Dan,

I spend a fair amount of time wild camping without access to purified water.  the systems I uses are:

1. Katerdan katadyn pocket water filter  If you are spending multi weeks away from purified water then this is the one to go for.  it is VERY robust and filters the water much quicker than most other filters and will take out all the bacteria and cysts inc Giardia and Cryptosporidium.  Some people are put off this filter because it doesn't filter out viruses (no filter only solution does)  However if you look into the subject more closely you will find that water born virus infection is almost never a problem  especially when you have filter out all the particulate matter - especially outside of urban areas.  The down side is that all that robustness adds to it weight 550grams!!  However When I know that I am going to be more than a few days away from clean water this is unit that I depend on.

2. I some times use Chlorine Dioxide Drops  good points is that they are cheep and light and there is almost no taint  to the water.  Bad points is that they it is a faff to use.  you have to mix 10 drops of each solution in one of the caps wait 10 minuets  then add mix to the water and wait a further 20 minutes (check the instructions as this is from memory)  So for the first 10 minutes you cant even carry on walking as you dont now have a cap on one of your bottle.  I suppose you could carry a separate screw top bottle but it is still a fiddly system.  I use them when going for 1 or 2 night out any longer and I use a different system.

3. If I am bush-crafting rather than hillwalking I use a millbank bag and boil the water over an open fire.  I do this last thing at night and then pour the water into my bottle then rap the bottle in something and shove it in my sleeping bag - toasty warm!

4. As a backup I also often carry some Chlorine Dioxide Tablets  These taste much better than Chlorine tablets but are also much more expensive.

I have considered several times getting a UV pen to sterilise water. I continue to here good things about them and  I think if I travelled mainly in an urban environment this would prove a good solution, as it a great deal lighter than the Katadyn. However when it comes down to it,  and especially in the wild,  I don't want to entrust my life to what amounts to a light bulb and battery system!

[Danneaux]

Hi All,

Hearing about other ways to do things is always valuable, and often causes me to take a second look at methods that may not have worked well for me. <nods> I agree; one solution often isn't enough, and with something as important as avoiding water-borne/caused illness on-tour, I just don't want to take any chances; hence my range of (heavy) solutions. I do love my Steri-Pen, but would never trust it as my sole solution for the very reasons Myles mentioned. Stuart, you put it nicely...

especially in the wild,  I don't want to entrust my life to what amounts to a light bulb and battery system!

Yep! Belt-and-suspenders for me!

Stuart, I'll take another look at the Katadyn. I haven't used that model, and the weight would surely be worth it if it is more robust than the other filters I've tried.

Some of the newer chemical-treatment pills offer a taste-neutralizer that really helps the treated product go down more easily. They also make time elastic; the minutes pass more slowly than when you're waiting for a drink of water!

Stuart, I need your help to understand a term unfamiliar to me...please, what is a "millbank bag"? I found a definition here: http://en.wikipedia.org/wiki/Millbank_bag and gather it is a canvas-like bag used for rough filtration? Do you have to clean it? Can it be dried? Can you tell me a bit more about it? Thanks!

Best,

Dan.

[Danneaux]

I asked...

please, what is a "millbank bag"?

I found: http://www.youtube.com/watch?v=iBHOQV7Brq0 ...and... http://www.youtube.com/watch?v=Xy762I7pbWs

Now I see! Surely clever, that! And, it beats using one of my spare socks for the purpose. 
 
Best,

Dan.

[stutho]

Sorry I missed the chance to reply to your millbank question.  I was AFK but yes basically yes it is a big sock it takes a while for the water to filter through but that is OK as you can be doing something else around your camp.  Millbank bags are suited to bush craft / static camp situations. I certainly don't take one when I am hillwalking or touring.    

With any method, it sure is hard to avoid incidental contamination...say unfiltered or unpurified water caught on bottle-cap threads, or opening the squirt nozzle on a bottle of clean water using fingers still-wet with contaminated water. I am really carefull to dry off a bottle so impure water won't run up the side as I tip the bottle to drink. And, I always clean my hands before and after purifying water.

If I am using a chemical treatment I always use a Nalgene water bottle (my main water container is a Source one bladder which is great by the way).  I fill up the bottle with dirty water put the chemical in and put top back on.  After the treatment time I turn the bottle upside down and slightly open the top to flush clean water and a little cleaning chemical over the threads of the bottle.  I now dry off the outside and consider the bottle fit to drink from.  

[StuntPilot]

On my continued quest to find equipment that can by powered by USB or solar for extended touring, I liked the idea of the Steri-Pen Freedom. It can be charged directly from The Plug 2 so would be an alternative to the Classic model.

http://www.steripen.com/freedom-travel

The MSR MiniWorks is mentioned by many bike tourers' blogs and seems to get good reviews. Also it is lighter than the Katadyne Pocket. Though I like the solid construction of the Pocket model.

http://cascadedesigns.com/en/msr/water-treatment-and-hydration/expedition-water-treatment-and-hydration/miniworks-ex-microfilter/product

[philb0412]

This is a great topic. Having had no experience of treating water before it is providing a good source of information for my upcoming trip.

I first investigated the Katadyn hiker, but then was erring towards a ceramic filter. I had hoped a ceramic filter, like the Katadyn mini or pocket would be a good investment, giving me years worth of cycle touring clean water just by pumping. Thus being a very green and environmentally friendly investment solution.

However, Dan, your comments about ceramic filters requiring a great effort and their dubious lifespan have now caused me to rethink before I invest. Have other people had similar experiences with ceramic filters?

[Danneaux]

Hi Phil and All,

However, Dan, your comments about ceramic filters requiring a great effort and their dubious lifespan have now caused me to rethink before I invest...

I hope my words haven't fostered the impression all ceramic filters are suspect; in truth, reviews on the 'Net by users and retailer sites indicate they are the first and most reliable choice for many people, who remain very happy with the concept and find them reliable.

That said, I thought it only fair to indicate my experience as a data point to consider. The ones I've tried haven't had a very long lifespan, either as a result of clogging or cracking. I do wish I knew why this was so, as I kind of had my heart set on a Ray Jardine-like gravity-feed filtering system for camp use. ( http://www.backpackinglight.com/cgi-bin/backpackinglight/reviews/display_reviews.html?forum_thread_id=1301&skip_to_post=8086 ). I figure there must be some flaw in my technique or use for my experience to be at variance with so many, though there is a subset of users who have had the same experience. I did take care to pack the filter carefully in my bags, padded by some clothing, and I also took care to carefully pre-filter debris from my water to prevent clogging. I am developing a theory that my clogging may have been caused by high mineral concentrations in the water where I tour, and that led to excessive pressure when I pump hard to avoid the clog. It is possible to build high internal hydraulic pressure at the filter, and I suspect it was my pumping effort on a partially mineral-clogged filter that caused the cracking -- not direct vibration while traveling (I never handled the thing roughly or dropped it). It may also be down to variations in pumping technique. I do know I manage to bottom-out my floor pump on each stroke, and that could surely crack a ceramic filter if the filter also served as a bottom-stroke travel stop.

And, yes, I'm the first to admit the thought of relying only on batteries and circuitry to purify my water makes me er, queasy. That's why I think it is really necessary to also carry at least one backup. The Steri-Pen works great when it works, which has been nearly all the time for me. There are some conditions where it just...does not. One example is where the water is too free of minerals to allow proper conductivity between the electrodes (fresh snowmelt, clear alpine streams). In that case, a pinch of salt is needed to make electrical contact. Easily addressed -- if you have the salt. The thing also swills batteries, and ordinary Alkaline AA cells just won't do the job, so one needs either high-capacity lithium disposable cells or (my choice) high-capacity rechargeables. <-- I understand this is one reason why Steri-Pen introduced the later model that used CR123 batteries; it proved more reliable to operate than those using AA Alkaline cells, which just aren't up to the job. I went with the Classic because a) I knew I could use rechargeable cells and b) it was on sale at ~60% reduction (which always appeals to me). There is another factor for those considering a Steri-Pen and that is user familiarity. I always play with mine just before a trip so I can be sure I have a handle on what it takes to use it correctly, as it is pretty easy to use it incorrectly -- it has to be turned on properly, the probes have to be immersed at the time, and it is absolutely critical to make sure the confirmation LED is properly lit...and it is hard to see in bright sunlight, requiring a cupped hand to make fully visible.  Still, it has been an extremely useful means to purify water in my circumstances, and unlike many, I've had good luck with it. It is nice to have clean water in only ~90 seconds, but it can always be dropped, and I don't think it would bounce too well. Belt-and-suspenders time! Call out the backup methods when/if that sad event happens.

By all means, Phil, I'd encourage you to consider all methods for water purification and definitely carry more than one as a backup. Water purity is critical on a bike tour, as the consequences of bad water can surely be devastating (diarrhoea, leading to advanced dehydration and electrolyte imbalance, which can even be life-threatening. Amoebic dysentery is no fun). At minimum, I'd suggest taking chemicals (pills, drops) as a lightweight backup plan to whatever you choose for a primary means of water purification.

I'm surely looking forward to hearing more from you as your trip-departure approaches, and more yet when you are on the road (if possible). All best wishes your way for a safe, fun, and happy adventure. How wonderful to contemplate!

Richard, that Steri-Pen Freedom surely looks the business in terms of a rechargeable solution. Why, oh why does the hand of Fate conspire to bring the most wonderful items to market after I make my purchases?   (lament of the Early Adopter). I know! I'm funding further research-and-development so others may benefit!   Ah, me. Well, I can recharge the batteries on mine (apart from the unit itself), so I get there in the end.    Good research, Richard; keep 'em coming...we're getting ever closer to Electrical Independence Through Bicycle Touring.  

Best,

Dan.