Drinking when travelling can quickly become a continuous quest, as this is our first vital need, and especially when visiting hot countries, or places with less developed sanitation infrastructures.
I first used water purification tablets when I climbed Mount Kenya in 2008. At the time, this was the only method I knew. I had to drink water from glacial lakes but also streams in which elephants may have peed, so this was the best option I knew of.
When you are very high in altitude, there are few animals, reducing the risk of direct water contamination. But there are still many bacteria potentially present. And I remember walking straight into an elephant footprint at lower altitudes when going to fill water tanks at the stream (being afraid or meeting it in person! as wild elephants can feel insecure when venturing to drink.) which meant that the same water could have been contaminated by fecal mater.
My experience of water purification systems has increased since then, and I thought it’d be useful to do a comparison.
An alternative to water purification can often be to buy bottled water, but as I want to reduce the amount of plastic and waste to a minimum in order to preserve our planet, I carry an aluminum water bottle with me at all times (e.g. Klean Kanteen is a great brand, without risks of having particles transfer into your water. I had other brands before but was seduced by this bottle when my girlfriend first discovered it in Canada last year), making more important to have a good water purification system. And when you are in remote areas such as in Patagonia where I trekked recently, or in a jungle in Indonesia, you may need to only rely on streams or other natural sources.
Why purify water ?
NB: in order to write this article and complement what I knew, I browsed a great resource on the REI website (LIEN: http://www.rei.com/learn/expert-advice/water-treatment-international.html)
Water-related problems can be caused by 3 types of pathogens, usually because of animal or human contamination, principally via fecal matter (poop):
- Protozoa and cysts (Cryptosporidium parvum, Giardia lamblia are the main ones). These single-cell parasites have a size between 1 and 20 microns
- Bacteria (Escherichia coli, Salmonella, Vibrio cholerae, Yersinia entercolitica, Leptospira interrogans and many more), with sizes between 0.1 and 10 microns
- Viruses (hepatitis A, rotavirus, enterovirus, norovirus). Those guys are extremely small between 0.005 and 0.1 micron, and are caused by human waste
Pumps (i.e. filters), act by physically separating protozoa and bacteria from water by pushing water through a ceramic cartridge with microscopic pores (between 0.2 and 0.4 microns). Water can flow through but protozoa, cysts and bacteria, can’t.
Viruses are much smaller and can still go through these pores, which is why this method needs to be complemented by another one. Killing viruses can be achieved either by boiling, “disinfecting” water with chemicals, or UV-based methods.
Spoiler alert: the method I recommend here, is therefore to use a UV device called Steripen, that effectively kills viruses, without all the drawbacks of the other methods. For the full comparision, here’s a detailed comparison between boiling, chemical-based, and UV-based methods:
Maybe the easiest method of all, and one that offers no doubt about potential harmful effects, but it is not the most practical.
Microorganisms and pathogens are killed in a few seconds when water reaches pasteurization temperatures (which are three: 60°C/131°F, 65°C/149°F and 70°C/158°F), so technically you don’t need to heat water up to 100°C, but it is just easier to do so because boiling provides visual evidence that the water has achieved a temperature above 70°C (how would you know for sure otherwise?)
- Effective against all waterborne pathogens. You can’t go wrong with this method.
- Need to have access to a heat source (a gas stove)
- You will be using up your gas supplies, you need to set up your stove, and have a pot handy
- You will have to wait before drinking the water, unless you want to drink it boiling!
NB: hepatitis A is extremely resistant. Even if we think it can be killed in less than 1 minute in water heated to 98°C/208°F, some health organizations and wilderness rangers still recommend at least 1 minute of boiling time to purify water, and 3 minutes at higher elevations, just to be sure.
3. Chemicals (Chlorine Dioxide Tablets)
The first chemical methods involved iodine and chlorine. More recent products contain Chlorine dioxide (e.g. Micropur tablets), which is better at killing bacteria and viruses than: they kill practically all water born viruses and bacteria, including Giardia, and Cryptosporidium. NB: the exact % is hard to find, if you know it, would love to hear from you in the comments!
Micropur is used in the form of a small pill containing chlorine dioxide, which effectively kill bacteria and viruses after only short contact times, and cysts (such as Giardia and Crypto) after longer periods.
- Very simple, light, and convenient. Just drop a tablet in 1L of water and wait.
- Wait time for Chlorine to be effective is usually 30 minutes, but can be as long as 4 hours if Cryptosporidium is a known risk. The colder and/or dirtier the water, the longer the recommended time.
- Water needs to be free of particles for chemicals to be effective, so you may need to filter first
- Water has a chlorine taste
- Not always effective against Cryptosporidium due to the bug’s egg like shell. More reliable options are UV light or boiling
- Over long periods of time, you will be drinking substantial amounts of Chlorine, which will weaken your immune system. I never like to put chemicals in my body! Why would this be good for you? That is just common sense too.
Drinking water that has been treated with Chlorine over a long period of time will make your immune system weaker, as the chemicals will build up in your body, which is not something I like.
This is a small pen-like device (a big larger, but with the same shape) that emits ultraviolet light to break the shells and DNA of bacteria and viruses present in the water. Short-wave UV light breaks their DNA, making them unable to reproduce and thus cause illness.
- No wait time is needed once water has been exposed to UV light.
- Causes no taste to the water.
- UV light is very effective against Cryptosporidium, the most treatment-resistant pest among protozoa and bacteria.
- The quartz lamp could break if your bag is taking shocks during travel (remember that public bus where they dropped your bag on the sidewalk at destination? Damn.) and if you don’t take sufficient care of the device.
- Batteries can run out. (The manufacturer recommends using lithium batteries or rechargeable NiCad batteries, the method I use since these are the same as what I power my flash lights with for photography, a great mutualized use!). However some travelers report a change of batteries may be needed almost every day if you purify a lot of water.
- Water needs to be free of particles for UV light to be able to interact with organisms and be effective. So you may need to filter it first.
I now use the SteriPEN every time I go somewhere I know I will need to purify my drinking water. The UV light is nice and it is fun to use. I even found that I could use the same batteries I used in my Nikon SB900 speedlights, and thus save on weight in my bags. Rechargeable batteries are even better for the SteriPEN as they deliver a higher Amp output. So this is a nice solution for a change!
Here’s a recap of the various water purification methods:
What is your experience with water purification methods when on autonomy treks in the wild or in remote countries? Have you also switched to the SteriPEN recently?
I’d love to hear your experience with it!