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When we’re in the back country on backpacking and canoeing trips we have to purify our water. I see providing safe drinking water as a group rather than an individual responsibility. It is also something that needs to be simple, as foolproof as possible and reasonably affordable.
I have tried several different filters and chemical treatments; all have had some significant drawbacks.
Chemical treatment requires careful measurement, timing the treatment and often results in a noticeable aftertaste.
Pump-type filters are prone to mechanical problems, need continual maintenance, are comparatively expensive, have complicated operating procedures and are slow in providing water for a large group of people. Pump type filters also need to be used at the water’s edge or require some sort of intermediate container to hold water.
We’ve been using the Katadyn Base Camp filter for the past several years and have found it to be simple and reliable. We carry one for every nine or ten people on backpacking and canoeing trips.
Gravity fed filters need no pumping. Simply fill the waterproof nylon reservoir with untreated water, hang it up and begin filling. Katadyn advertises that the filter delivers “up to 2.5 gallons of treated water in just 15 minutes”. Naturally as the filter ages the flow rate will reduce somewhat. A clip on the tubing acts as a spigot to control water flow.
The glasfiber filter elements are easy to replace and fairly inexpensive ($40.00 or so at this writing). We carry a spare filter element on weekend trips, and two spare elements on longer outings. It is important to prime the filter by allowing it to fill with water before using. We have also had instances when the filter seems to get air locked, but gentle pressure on the filled bag will aid in priming. If the untreated water has a fair amount of visible undissolved solids we use a collapsible bucket to allow the solids to settle before putting it in the filter. The filter weighs 22 ounces.
At around $70.00 the Base Camp is relatively inexpensive in comparison to pump-type filters. Even with replacing filters fairly often the price per person is very reasonable ($3.00-$4.00 per trip). More importantly the Base Camp Water Filter is easy to operate for even our youngest Scouts.
I was looking for such a system last summer when my Troop was doing a 4 day canoe trip. I had purchased 2 of these and they worked really great. Having 2 of them, filtering water in 5 gallon jugs was the best investment this Troop made and I would swear by them. The boys were able to fill them and filter water within 15-20 minutes and when we were all done the clean-up process was even easier. I definitely recommed this to anyone.
Our crew has never complained about a taste with Aquamira. My MIOX purifier did make the water smell like a swimming pool.
I have a couple of problems with filters. First, they assume that everything downstream of the filter is sterile, which is hilariously false in the backcountry. Second, something that is ineffective against a common pathogen doesn’t pass my risk management test.
Of course, washing hands is about 100X more important.
I don’t assume anything is sterile.
You have two or three groups of things downstream – water bottles, serving wear, and cook wear. Water bottles aren’t shared as a rule so the funk on them is your own. Serving wear gets sanitized with steramine and cook wear is heated to sterilizing temperatures.
We do agree that hand washing is the most important aspect of avoiding illness. We include a large pump container of waterless hand sanitizer. Everyone uses it before touching food and after ‘making like a cat’.
To my knowledge we’ve never had anyone contract a virus (or any other pathogen for that matter) over a decade or so of high adventure trips. The real danger for this has always been summer camp – too many people and too many common areas.
Except that it is ineffective against viruses.
I haven’t noticed any taste issues with chlorine dioxide, and the two-part liquid (Aquamira) is pretty cheap at $15 for 120 liters of treated water. Our crews have not had any issues with timing — you mix the two part solution before going down to fetch the water, when you come back, the five minutes have passed. Stack up all the water bottles in one spot, wait 15 minutes, then call “water’s ready”. Do this in the evening, and most bottles get overnight to kill those pesky cryptosporidium cysts.
The Centers for Disease Control has an excellent page on backcountry water treatment. The HTML version is hard to understand, so you really should look at the PDF version.
http://www.cdc.gov/healthywater/drinking/travel/backcountry_water_treatment.html
http://www.cdc.gov/healthywater/pdf/drinking/Backcountry_Water_Treatment.pdf
Here is a summary of the CDC’s table. On a 0-4 scale, where 0 is “ineffective”, here are the scores for cryptosporidium, giardia, bacteria, and viruses:
Boiling: 4, 4, 4, 4
Filtration 1 micron: 3, 3, 0, 0
Filtration 0.3 micron: 3, 3, 2, 0
Iodine or Chlorine: 0, 1-2, 3, 3
Chlorine dioxide: 1-2, 3, 3, 3
Filtration + disinfection: 4, 4, 4, 3
The Katadyn Base Camp is a 0.3 micron filter.
I’ve used Aquamira and it is a good system. We carry it to backup our filter system. We did have two basic concerns: aftertaste and the relative difficulty of use.
The Katadyn filter is a much simpler to use – fill it up and get filtered water – I am completely comfortable with Scouts using it unsupervised. The Aquamira treatment is more difficult and more prone to mistakes.
After filling water bottles with untreated water and treating with Aquamira the lid and mouth of the bottle still have untreated water on them, you’re supposed to apply the lid loosely and shake the bottle so a bit of the treatment sanitizes the lids and mouth of the bottle. With the filter the bottles don’t touch untreated water.
Cost wise they are both about the same Aquamira treats 30 gallons for $15 and the Katadyn reliably filters about 90 gallons per $40.00 cartridge.
All that being said the most bombproof way to treat water is boiling or filtering and treating. We never use treated water for cooking since it is boiled anyway and can treat drinking water with both filtering and Aquamira if it is suspect.
Great review…I have been thinking about investing in 2 of these…1 for me, and another for the troop. It’s a lot less “mechanical” so there wouldn’t be any repair kit that would need to be hauled along, or pieces to break.
As for the muddy/mucky water, could you filter it with some coffee filters? They weigh nothing, and a coffee filter has 1000 uses. Thanks for the review.