View Full Version : Winter water treatment
300winmag
12-08-2010, 18:10
As I see it you have only 3 distinct water treatment options for winter.
1. boiling creek water or melting snow to a boil
2. UV ray treatment (SteriPen) Cold water does not affect its effectiveness BUT you should try to keep the batteries warm.
3. Chlorine dioxide tablets (Katadyn Micropur tabs) Here very cold water requires you to let it dissolve over 4 hours for max effectiveness unless you put it in warmed water.
Taking both #s 2 & 3 seem prudent. I do it all year long.
garlic08
12-08-2010, 18:45
There is another option. In my view, snow is perhaps the cleanest, purest substance on Earth (with some colorful, easily avoided exceptions). So no need to boil, in my opinion. Merely melting the stuff takes far less energy.
It's certainly prudent to have some treatment system for suspect surface water that won't freeze up.
Toolshed
12-08-2010, 21:09
There is another option. In my view, snow is perhaps the cleanest, purest substance on Earth (with some colorful, easily avoided exceptions). So no need to boil, in my opinion. Merely melting the stuff takes far less energy.
It's certainly prudent to have some treatment system for suspect surface water that won't freeze up.
Ditto on no need to boil. Also, always start with water or ice in the pot. If you start with just snow, you run a risk of scorching your pan especially with dry snow (assuming you are using something along the lines of a pressurized liquid fuel stove like a whisperlite for your winter activities).
I suppose it depends on your definition of winter, but I had good luck with my Katadyn pocket filter. It froze only twice on me on the southern AT, and as I had pumped it dry sideways per the instructions, I suspect it was due to a bit left in the spout. By making a double-boiler with my pot, I was able to defrost it in about 30 seconds. If any damage was done to the cartridge, I never noticed and used it till it wore out several thousands of gallons later. I tried to store my filter in a warmer place (buried deep in the pack or near me) during the day to help keep it warm, but there's only so many things you can keep warm. Compared to the fuel needed to melt snow, the weight savings were immense, and when the weather warmed up, as well as before it got cold, I had a good filter.
The two times it froze were a bit of an anomaly, yet on many of the days when it didn't freeze, the same weather would make my writing pen worthless and freeze any lighter not worn next to the skin. Granted it wasn't that cold, just cold for the southern AT; I'm a bit of weather wimp and never willing go out unless it's over -20F, as judged by my eyelashes.
I would be very weary of depending on batteries. Like a lighter, they tend to require extra care in cold weather.
Tipi Walter
12-09-2010, 09:05
The main question with filters like the Hiker is, does freezing and then thawing ruin its filtering ability? Any tests on this? I use an old PUR Hiker and take it out in the winter and of course at 0F it's useless unless I thaw it out either next to my body or inside the sleeping bag or by laying it out in the sun for an hour or two. Then it works okay, but I'm not sure if it is really working in purification mode.
Put me in the 'melting snow' camp. The water sources are often (not always) frozen in deep winter, anyway.... :)
Melting snow is definitely an option. I have done it on a number of occasions. I would not say, however, that it takes less energy. Melting snow as your main method of getting drinking water is very energy intensive, both fuel and physical/time. It takes a lot of snow to fill a water bottle. Also, if you don't plan to treat it, you still need to pay close attention to it's purity. Unlike flowing water, the same snow sits around for weeks, even months at a time and so can potentially become quite contaminated in some areas.
As mentioned, obviously, yellow snow is not you best choice, even more dangerous is pink snow (not really a problem here in the east I don't believe). It contains a fungus that can make you quite ill.
Also, I used to be in the camp of folks who thought it best to fill your pot in the evening, thinking that when frozen in the AM, I could just place it on the stove and be happy. It works, but someone reminded me of the Latent Heat from Physics for changing H2O from one state to another. It takes about double the calories (energy) to heat ice one degree as it does to heat water one degree. Thus you will expend twice as much fuel to melt ice as you would to just heat water. Check this out if you are interested:
http://www.school-for-champions.com/science/heat_ice_steam.htm
From my experience, filters are a pain in the butt all the time, but especially so in winter.
Anyway, just a few more things to consider.
Snowleopard
12-09-2010, 13:20
It's too hard to keep filters from freezing in the cold. Freezing water expands and it might crack the active part of the filter so it doesn't filter out the nasties anymore.
Chemical treatments take longer in cold temperatures. At 32F it would take a looooong time even if you have liquid water available.
The UV treatments, like steripen should work if you have liquid water, but batteries don't last as long in the cold (lithium batteries are a lot better than alkaline). This might be the easiest choice if you have access to liquid water.
Melting snow/ice takes a lot of fuel. If you have melt snow anyway you might as well boil it. Make an effort to find liquid water in winter, because it takes a lot of fuel just to melt snow/ice at 32F into liquid at 32F.